150,735 results on '"soils"'
Search Results
2. Lateral kinematic properties of offshore pipe piles embedded in saturated soil considering soil plug effect.
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Li, Jiaxuan, Yang, Xiaoyan, Liu, Hao, Chen, Libo, Wu, Wenbing, Naggar, M. Hesham El, and Lu, Dagang
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DYNAMIC stiffness , *WATERLOGGING (Soils) , *MODULUS of rigidity , *FREQUENCIES of oscillating systems , *SOILS - Abstract
This study establishes a theoretical framework for analyzing the lateral oscillation of marine pipe piles. The additional mass model is introduced herein to consider the inertial fluctuation effect of the soil plug. Analytical mathematical methods are used to determine the complex impedance variation of the pile over a range of frequency effects. An investigation is performed to determine how the presence of soil plugs changes the lateral complex stiffness and natural frequency of pipe piles. Additionally, comparisons of the applicability of the plane strain model and continuous medium model have been conducted to enable the easy use of the theoretical model. The main conclusions can be drawn as (1) if the fluctuation inertia effect of the soil plug is not taken into consideration, the dynamic active length and the dynamic stiffness of the pipe pile will be underestimated; (2) for the soft soil, the plane strain model may give rise to substantial calculation errors attributed to them regardless of the vertical continuity of the soil, nevertheless, the calculation error decreases rapidly with the increase of soil shear modulus and vibration frequency. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Study on the Effect of Soil Type and Salinity on Water–Soil Characteristic Curves of Saline Soils Based on the Vapor Balance Technique.
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Zhao, Tianyu, Li, Lunji, Zhang, Huyuan, An, Liang, Liu, Wanming, Wang, Yingchun, and Nian, Tengfei
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SOIL salinity ,SOIL moisture ,SOIL classification ,SOILS ,VAPORS - Abstract
The soil–water characteristic curve (SWCC) describes the relationship between water content and soil suction, which is an important tool for determining the engineering properties of unsaturated soil. By measuring SWCC through vapor equilibrium technique, which could obtain soil suction up to 309 MPa, this paper explored the influences of the soil type and salt content on SWCC of saline soil. The experimental results illustrate that fine‐grained saline soil had a good water‐holding capacity, which had a higher air entry value and slower dehydrate rate. The study also brings out the observation that salt had negligible influence on soil suction and parameters effecting SWCC in low suction range; however, this effects was slight until it disappeared with the suction increasing. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Role of Clay Minerals in Natural Media Self-Regeneration from Organic Pollution-Prospects for Nature-Inspired Water Treatments.
- Author
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Azzouz, Abdelkrim, Dewez, David, Benghaffour, Amina, Hausler, Robert, and Roy, René
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BIOLOGICAL treatment of water , *PARTIAL oxidation , *CLAY soils , *CHEMICAL decomposition , *CLAY minerals - Abstract
Pollution from organic molecules is a major environmental issue that needs to be addressed because of the negative impacts of both the harmfulness of the molecule structures and the toxicity that can spread through natural media. This is mainly due to their unavoidable partial oxidation under exposure to air and solar radiation into diverse derivatives. Even when insoluble, the latter can be dispersed in aqueous media through solvatation and/or complexation with soluble species. Coagulation–flocculation, biological water treatments or adsorption on solids cannot result in a total elimination of organic pollutants. Chemical degradation by chlorine and/or oxygen-based oxidizing agents is not a viable approach due to incomplete mineralization into carbon dioxide and other oxides. A more judicious strategy resides in mimicking natural oxidation under ambient conditions. Soils and aqueous clay suspensions are known to display adsorptive and catalytic properties, and slow and complete self-regeneration can be achieved in an optimum time frame with a much slower pollution throughput. A deep knowledge of the behavior of aluminosilicates and of oxidizing species in soils and aquatic media allows us to gain an understanding of their roles in natural oxidative processes. Their individual and combined contributions will be discussed in the present critical analysis of the reported literature. [ABSTRACT FROM AUTHOR]
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- 2024
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5. An updated method for identifying the formative factors in soil structure.
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Anderson, Amber D., Burras, C. Lee, Turk, Judith, Young, Rebecca, Jelinski, Nic, Moorberg, Colby, Presley, DeAnn, Osterloh, Kris, Dere, Ashlee, and Clark, Kerry
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SOIL structure , *SOIL scientists , *SOIL science , *SOIL formation , *SOILS - Abstract
Soil structure is a standard component of pedon descriptions collected to characterize the nature and function of soils as a natural body. Soil structure is an important indicator of soil development and a predictor of water, air, and root movement throughout the profile. However, inconsistencies exist within the current standardized methodologies used to describe soil structure in the field, making soil structure data difficult to use and often confusing to students encountering these concepts for the first time. Therefore, we propose an updated method of soil structure description to add an interpretive component that clearly distinguishes geogenic, pedogenic, and human‐induced structures. This method employs terminology that communicates both observable morphology and the mechanism of formation. The updated method herein differentiates three classes of structure: (a) geogenic structural formation (GS), (b) natural pedological structural formation (current nomenclature), and (c) significant human‐induced structure changes from natural pedological structure. This updated approach improves the documentation of scientifically relevant soil morphology and communicates the processes involved in the formation of all forms of soil structure. As a result, this change eases description challenges around soil structure and interpretations common in soil science classes, including soil judging. Core Ideas: Soil structure falls into three categories: (1) natural pedogenic; (2) geogenic; and (3) human‐induced.Soil education would be improved by distinguishing formation factors for soil unit breaks.Experienced field soil scientists easily recognize these differences, but those just learning do not. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Putting the soil health principles to the test in Iowa.
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McDaniel, M. D. and Middleton, T. A.
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CONSERVATION of natural resources , *SOIL management , *SOIL conservation , *CARBON in soils , *SOILS - Abstract
One of the most popular soil conservation campaigns is based on the USDA Natural Resource Conservation Service's Soil Health Principles (NRCS‐SHPs). The NRCS‐SHP program identifies four principles—maximize presence of living roots, minimize disturbance, maximize soil cover, and maximize biodiversity—with the underlying assumption that the more principles one follows, the greater improvements in soil health. Despite the popularity of the NRCS‐SHPs, this underlying assumption has not been rigorously tested. To do so, we used nine long‐term experiments all located in central Iowa, but with varying degree of NRCS‐SHP adoption, to determine if greater adoption increases three slow‐changing (maximum water holding capacity, bulk density [BD], and soil organic carbon) and three dynamic (microbial biomass carbon [MBC], potentially mineralizable carbon [PMC], and permanganate oxidizable carbon [POXC]) soil health indicators. We regressed these indicators with a soil health principle score that can scale soil management based on adoption of the NRCS‐SHPs. Of the slow‐changing soil properties, increased adoption of NRCS‐SHPs only decreased soil BD (R2 = 0.22, p = 0.024). On the other hand, increased adoption of NRCS‐SHPs strongly predicted increases in both MBC and PMC and across two sampling dates (R2 > 0.23, p < 0.015); POXC, however, did not increase with greater adoption. The consistent increases in MBC and PMC with greater adoption of NRCS‐SHPs supports their usefulness as sensitive indicators of positive soil health change. Our study provides scientific evidence to support the NRCS‐SHPs concept, improving its usefulness as an extension campaign, and stands as a step toward evidence‐based soil conservation. Core Ideas: The NRCS Soil Health Principles (NRCS‐SHPs) combined effects stand untested.We used a novel metric and six soil health indicators across nine long‐term experiments in Iowa to test it.Soil organic carbon, permanganate oxidizable carbon, and water holding capacity did not relate to NRCS‐SHPs.Bulk density decreased with greater adoption of NRCS‐SHPs.Microbial biomass and potentially mineralizable carbon increased with NRCS‐SHPs adoption. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Analysis of the effect of breakable particle corners on uplift pile–soil interaction behaviors in calcareous sand.
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Peng, Yu, Yin, Zhen-Yu, Yang, Fengchun, Qu, Liming, and Ding, Xuanming
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SILICA sand , *CALCAREOUS soils , *STRESS concentration , *SAND , *SOILS - Abstract
The effect of breakable particle corners is often overlooked in research on pile–soil interaction, which hinders the understanding of the uplift pile behaviors in calcareous sand. This research examines the breakable corner effects on uplift pile–soil interaction in calcareous sand from macro to micro, through model tests and coupled discrete element method–finite difference method. Results revealed that compared to that in silica sand, the higher bearing capacity and relatively abrupt failure behavior of uplift piles in calcareous sands were attributed to the corner interlocking effect and corner breakage effect, respectively. The unstable load transmission along piles in calcareous sand was thoroughly explained by a coupled effect of corner interlocking and breakage. Furthermore, the reduction in effective contacts and alterations in soil skeletons were identified as critical factors contributing to the distinctive soil behaviors in calcareous sand. Moreover, the relative sliding distance of particles was found to be the key factor in determining the amount of corner breakages due to stress concentration at corners. Lastly, a positive feedback loop involving corner breakage effects was proposed, successfully explaining the distinctive phenomenon of uplift piles in calcareous sand. This study provides new perspectives to clarify distinctive pile–soil interaction behaviors in calcareous sand. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Free strain consolidation of soft ground improved by stone columns under time-dependent loading considering smear effects.
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Liu, Yang, Wu, Peichen, Yin, Jian-Hua, and Zheng, Jun-Jie
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PORE water pressure , *STONE columns , *PARTIAL differential equations , *SETTLEMENT of structures , *SOILS - Abstract
This paper presents a consolidation model for stone column-reinforced soft ground subjected to time-dependent loading under free strain condition. Smear effects and three types of loadings, namely, constant loading, ramp loading, and sinusoidal loading, are considered in the developed consolidation model, which is solved by a numerical method based on a partial differential equation solver. The applicability of the proposed consolidation model and the reliability of the numerical method are demonstrated and verified by well-predicting the consolidation behaviors of two practical engineering cases and one laboratory experiment. The verified model and the numerical method are then employed to investigate the effects of smear zone and time-dependent loading on consolidation characteristics of stone column-improved soft ground. The results indicate that the excess pore water pressure undergoes a sharp change at the interface between the smear zone and the undisturbed zone due to smear effects. The smaller the range of the smear zone, the faster the settlement of the composite foundation develops. The faster the loading rate, the faster the dissipation of excess pore water pressure and the faster the settlement develops. In addition, for the foundation subjected to sinusoidal loading, the higher loading frequency results in a larger amplitude corresponding to the excess pore water pressure and a smaller amplitude corresponding to the settlement of the soil. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Coupled influence of geosynthetic reinforcement and column configuration on failure dynamics in deep mixed columns under embankment loading.
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Zheng, Gang, lv, Lei, Yu, Xiaoxuan, and Zhou, Haizuo
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SHEAR strain , *FAILURE mode & effects analysis , *EMBANKMENTS , *GEOSYNTHETICS , *SOILS - Abstract
The design of column-supported embankments requires a comprehensive evaluation of overall stability and failure mechanisms. Previous research has investigated stress characteristics and failure modes of deep mixing (DM) columns under embankment loads. Depending on column configurations, those near the embankment toe experience flexural potential bending or tilting failure, while those closer to the centre are prone to shear failure. As column spacing decreases, a shift from bending to tilting failure occurs. Inadequate column bending capacity increases the risk of tilting-induced embankment collapse. This study initially showcases the efficacy of geosynthetics in mitigating tilting failure in columns with smaller spacings. The interaction between geosynthetics and diverse configurations on the failure mechanisms of DM columns is meticulously examined. A crucial shift in the failure mechanism from tilting to bending is facilitated by the application of conventional geosynthetics with tensile stiffness, particularly in scenarios with restricted spacing. Geosynthetics effectively mitigate lateral soil displacement, enhance column bending capacity, and intricately redistribute lateral pressures exerted on the columns. Ultimate load, shear strain, and stress are analysed both with and without geosynthetics. Lastly, the influence of geosynthetics on soil reaction distribution and internal forces within columns is deliberated. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Spatial variability of sulphur fractions in soils of agro-climatic zone-II, Himachal Himalaya, India.
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Suri, Deepika, Sharma, Vijay Kumar, Kumar, Pardeep, Kumar, Praveen, Sharma, Munish, and Butail, Nagender Pal
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SULFUR , *SOIL management , *PRINCIPAL components analysis , *SOILS , *CARBON in soils - Abstract
Estimating spatial variability of soil nutrients and their fractions is important for understanding their dynamic distribution under various pools. The present study was carried out to examine the spatial distribution of soil sulphur (S) fractions in agro-climatic zone-II (mid hills sub-humid) of Himachal Himalaya, India. The data were analysed with a classical and geostatistical approaches. The soil organic carbon varies from 2.8 to 22 g/kg and the S-fractions are positively correlated with organic carbon. The total-S varies from 72.6 to 513.9 mg/kg with a mean value of 260.9 mg/kg. The descriptive analysis showed that the coefficient of variation ranged from 8.5% to 52.9%. Semivariogram modelling represents that the best-fitted model was exponential and the nugget-to-sill ratio {(C0/C0 + C)} explains the spatial dependency, suggesting a moderate spatial dependence. The principal component analysis represents the three principal components that explain the 91% variance in the dataset. The higher concentration of sulphur is well correlated with soil organic carbon. The present study provides information to understand sulphur dynamics through their partitioning among various pools for effective soil resource management. [ABSTRACT FROM AUTHOR]
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- 2024
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11. A Cam Clay constitutive relation for semi-analytical elasto-plastic modeling of wheel-soil interaction for fast applications.
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Rahimi, Amir-Hossein, Azimi, Ali, and Goudarzi, Taha
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MULTIBODY systems , *CLAY , *VELOCITY , *SOILS - Abstract
AbstractIn this paper, a semi-analytical elasto-plastic (SAEP) model is proposed to simulate wheel motion on soft soil using a Modified Cam Clay (MCC) constitutive model. The focus is on enhancing computational efficiency by integrating the MCC model into the framework. The MCC-based model outperforms the Drucker-Prager with Cap hardening (DPC)-based model in terms of reduced computation time, stability, and convergence. Simulations with a 30% slip ratio show a significant reduction in solution time compared to the DPC-based model. For slip ratios of 50% and 90%, the computation time decreases even further. Overall, the MCC-based model demonstrates over 100 times reduction in the solution time compared to the DPC-based model, particularly with high slip ratios. Indeed, the DPC-based model was found to be highly sensitive to high values of slip ratios, whereas the MCC-based model is not. In comparison with existing methods in the literature, the proposed formulation is superior in terms of significantly reduced solution time and improved numerical stability, making it ideal for advanced applications where fast solutions are crucial. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Hybrid method for rainfall-induced regional landslide susceptibility mapping.
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Wu, Shuangyi, Wang, Huaan, Zhang, Jie, and Qin, Haijun
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LOGISTIC regression analysis , *REGRESSION analysis , *SOILS , *LANDSLIDE hazard analysis , *LANDSLIDES - Abstract
Landslide susceptibility maps can provide important information for managing regional landslide risks. Traditionally, data-driven and physically-based models are widely used for rainfall-induced landslide susceptibility mapping, but each method has limitations. In this study, a hybrid method that integrates a data-driven model and a physically-based model is proposed for rainfall-induced landslide susceptibility mapping, where the uncertainty in the soil properties can be explicitly considered. The proposed method is illustrated with landslide susceptibility mapping in Shengzhou County, Zhejiang Province, China. Logistic regression is used as the data-driven model, and the regional assessment of rainfall-induced landslides model (RARIL) is used as the physically-based model. Three hybrid models are developed. Hybrid model I, which considers soil parameters uncertainty, is compared with hybrid models II and III, which do not consider it. Results indicate that all the three hybrid models outperform the conventional logistic regression and RARIL models. Notably, hybrid model I, which considers the soil parameters uncertainty, outperforms hybrid models II and III, which do not consider it. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Distribution of phosphorus forms in soil amended with poultry litter of different ages and application rates: Agronomic and environmental perspectives.
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Chakraborty, Debolina, Prasad, Rishi, Feng, Hanxiao, Watts, Dexter B., and Torbert, H. Allen
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POULTRY litter , *PHOSPHATE fertilizers , *PHOSPHORUS in soils , *SOILS , *BIOAVAILABILITY - Abstract
Poultry litter (PL) can be used as a viable alternative to phosphate fertilizers. However, there is a lack of information about phosphorus (P) distribution in inorganic (Pi) and organic (Po) forms and its transformation in soils amended with PL of varying age (based on litter clean‐out frequency) and application rate. This study aimed to determine the effect of PL age and application rate on soil P forms and their bioavailability. Soils were amended with 5 and 10 Mg ha−1 PL using 6‐, 18‐, and 30‐month‐old litter and incubated for 6 months. Soil P fractionation was performed following the Hedley protocol. Soil P availability and soil P storage capacity (SPSC) were determined using Mehlich 3 (M3) extraction. Results indicated that P transformation from labile to stable P forms occurred over 150‐day incubation. Litter age had no significant effect on the distribution of soil P forms. However, the highly reactive Pi (HRPi) form was higher for treatments with 10 Mg ha−1 PL on Day 0, indicating a risk for P loss, which was also revealed by negative SPSC for those treatments. At Day 0, M3‐P was positively correlated to HRPi. However, from Day 30 to 150, M3‐P was strongly correlated to both HRPi and moderately reactive Pi (MRPi) forms, indicating MRPi contribution to soil P availability. The negative relationship between HRPi and SPSC further confirms that high HRPi on Day 0 may be an environmental concern. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Advances and perspectives of research on soil moisture response to afforestation: a review.
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Kong, Wei, Gao, Fei, Sun, Shikun, Lei, Yuhan, Gu, Jiali, and Luan, Xiaobo
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SOIL productivity , *SOIL moisture , *AFFORESTATION , *SOILS , *HETEROGENEITY - Abstract
The soil moisture (SM) balance is affected by afforestation. In this study, the CiteSpace software was used to review the literature on the impact of afforestation on SM, and we further present research findings on the Loess Plateau (LP) as follows: (1) the spatio-temporal heterogeneity of SM varies depending on the research scale; (2) the presence of a dried soil layer significantly hinders deep SM recharge; (3) the accumulation of net primary productivity (NPP) may be occurring at the expense of SM. The following research topics are discussed: (1) the recharge and consumption of deep SM in LP; (2) the green water footprint and its shortage of non-crop greenery for evaluating SM allocation and use; (3) the development of inclusive models encompassing different spatial scales to assess the limits of soil water carrying capacity for vegetation (SWCCV). [ABSTRACT FROM AUTHOR]
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- 2024
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15. Radon gas and geomorphic analysis as supportive tools for fault exploration: an example from the Aba South Fault basin, western Sichuan.
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Kang, Guichuan, He, Li, He, Zhengwei, Wu, Xiaoyi, and Guan, Sensen
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TECTONIC landforms , *MORPHOTECTONICS , *GAS analysis , *RADON , *SOILS , *GEOMORPHOLOGY - Abstract
Clarifying the response relationship between soil radon gas anomalies and active fault tectonic geomorphology, and to explore a rapid prediction method for concealed fractures, soil radon gas measurements and unmanned aerial vehicle micro-geomorphic scanning were carried out in the basin section of the Aba South Fault in western Sichuan. The areas of radon gas anomalies and tectonic features formed by fracture activities are highly consistent with the distribution areas of hidden fractures. It is concluded that the combination of soil radon gas measurements and tectonic geomorphologic analysis can rapidly and accurately predict hidden fractures covered by Quaternary sediments. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Vertical distribution of radioactive cesium rich microparticles in Fukushima soils.
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Tatsuno, Takahiro, Waki, Hiromichi, Kakuma, Minato, Nihei, Naoto, and Ohte, Nobuhito
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NUCLEAR power plant accidents , *SOIL depth , *CESIUM , *SOILS - Abstract
Radioactive cesium rich microparticles (CsMPs) could partially increase 137Cs concentration of the samples collected from the environment after the Fukushima Daiichi Nuclear Power Plant accident. In this study, we investigated the vertical distribution of CsMPs in soils collected from Fukushima Prefecture, Japan. The distribution of CsMPs was relatively large in the soil surface layer. However, the proportion of CsMPs in the RCs concentration at each soil depth was not large, less than 10%. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Assessment of radioactivity levels in soil of coastal dwellings in Odisha and Andhra Pradesh, India.
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Kumar, N. S. Siva, Raju, M. Kumar, Ratnaraju, M., Satyanarayana, G. V. V., VidyaSagar, D., and Das, N. Lakshmana
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GAMMA ray spectrometry , *ABSORBED dose , *RADIOACTIVITY , *RADIATION , *SOILS - Abstract
The activity concentrations of 238U, 232Th, and 40K were determined at 56 sites along the East Coast of India, near the Bay of Bengal, with 31 sites in Odisha and 25 in Andhra Pradesh. In Odisha, average concentrations were 109 ± 13 Bq kg−1 for 238U, 296 ± 27 Bq kg−1 for 232Th, and 450 ± 33 Bq kg−1 for 40K, while in Andhra Pradesh, they were 51 ± 13 Bq kg−1, 149 ± 16 Bq kg−1, and 236 ± 21 Bq kg−1, respectively. Absorbed dose rates and annual effective doses were higher outdoors and indoors in Odisha compared to Andhra Pradesh. The calculated radiological parameters exhibited elevated values at certain sampling locations; however, overall, the values generally complied with regulatory standards. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Decolonising the Earth: Anticolonial Environmentalism and the Soil of Empire.
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Davidson, Joe P. L. and Carreira da Silva, Filipe
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ENVIRONMENTALISM , *HUMANITY , *SOILS , *ECOLOGY , *COLONIES - Abstract
The relationship between humanity and the soil is an increasingly important topic in social theory. However, conceptualisations of the soil developed by anticolonial thinkers at the high point of the movement for self-determination between the 1940s and the 1970s have remained largely ignored. This is a shame, not least because theorists like Eric Williams, Walter Rodney, Suzanne Césaire and Amílcar Cabral were concerned with the soil. Building on recent work on human-soil relations and decolonial ecology, we argue that these four thinkers conceptualised the connection between soil, empire, and anticolonial revolt. Williams and Rodney ground understanding of soil degradation in global relations of economic power, while Césaire and Cabral reconceptualise postcolonial nationhood in terms of the mutability and diversity of the soil. The article concludes by suggesting that these two anticolonial counterpoints, global connectivity and more-than-human identification, anticipate and deepen contemporary attempts to decolonise ecological thinking. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Quantifying particle breakage through a shape factor of the particle size distribution.
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Salami, Younes, Konrad, Jean-Marie, and Jaafri, Reda
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PARTICLE size distribution , *GRANULAR materials , *SOIL granularity , *SLOPES (Soil mechanics) , *SOILS - Abstract
Quantifying the process of particle breakage is essential whenever a macroscopic investigation into the phenomenon is addressed. Some authors relate an indicator of the evolution of particle breakage, usually the surface created, to a measure of the mechanical loading. Others refer to the evolution of the particle size distribution (PSD) to better understand the problem. In this study, a shape factor of the PSD curve is used as a breakage parameter. The slope of the linear trendline of the PSD in a log-log plot was found to be reasonably representative of the shape of the PSD, for engineering granular materials. It was shown that the new breakage parameter is adapted to both well graded and uniformly graded materials, but cannot be used to describe gap-graded soils. This parameter is first studied from a micromechanical point of view, before being compared to three widely used breakage parameters: Hardin, Marsal and Einav's breakage parameters. The transition between these three parameters and the proposed parameter is provided. The main objective of this study is to allow the operation and utilisation of experimental results, which are reported in the literature through one of the available breakage parameters, or through PSD plots. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Multistep procedure for estimating non-linear soil response in low seismicity areas—a case study of Lucerne, Switzerland.
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Janusz, Paulina, Bergamo, Paolo, Bonilla, Luis Fabian, Panzera, Francesco, Roten, Daniel, Loviknes, Karina, and Fäh, Donat
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EARTHQUAKE hazard analysis , *GROUND motion , *CONE penetration tests , *THEORY of wave motion , *SOILS - Abstract
The impact of non-linear soil behaviour on seismic hazard in low-to-moderate seismicity areas is often neglected; however, it may become relevant for long return periods. In this study, we used fully non-linear 1-D simulations to estimate the site-specific non-linear soil response in the low seismicity area, using the city of Lucerne in Switzerland as an example. The constitutive model considers the development of pore pressure excess and requires calibration of complex soil models, including the soil dilatancy parameters. In the absence of laboratory measurements, we mainly used the cone penetration test data to estimate the model variables and perform inversion for the dilatancy parameters. Our findings, using Swiss building code-compatible input ground motions, suggest a high probability of strong non-linear behaviour and the possibility of liquefaction at high ground motion levels in the case study area. While the non-linearity observations from strong-motion recordings are not available in Lucerne, the comparison with empirical data from other sites and other methods shows similarity with our predictions. Moreover, we show that the site response modelled is largely influenced by the strong pore pressure effects produced in thin sandy water-saturated layers. In addition, we demonstrate that the variability of the results due to the input motion and the soil parameters is significant, but within reasonable bounds. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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21. Two-Scale Probabilistic Seismic Fragility Assessment for a Prestressed Concrete-Steel Hybrid Wind Turbine Tower with Incremental Dynamic and Multiple Stripe Analysis.
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Li, Zeyu, Xu, Bin, and Zhao, Ye
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WIND turbines , *SOIL classification , *STRIPES , *VELOCITY , *SOILS - Abstract
To evaluate the seismic performance of a prestressed concrete-steel hybrid (PCSH) wind turbine tower, the seismic fragility curves based on incremental dynamic analysis (IDA) and multiple stripe analysis (MSA) on a two-scale model are presented and compared. The peak ground acceleration (PGA) and peak lateral drift on the top of the tower are adopted as the intensity measure (IM) and engineering demand parameter (EDP) of analysis, respectively. Finally, the seismic performance of the PCSH tower subjected to seismic action at different soil is investigated. The fragility curves obtained by IDA and MSA methods are compared. [ABSTRACT FROM AUTHOR]
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- 2024
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22. The small-strain stiffness of a railway ballast.
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Altuhafi, Fatin N. and Coop, Matthew R.
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SHEAR strain , *MODULUS of elasticity , *MODULUS of rigidity , *SOILS , *RAILROADS - Abstract
The large particle sizes of railway ballast and rock fill have meant that conventional techniques used to measure the small-strain stiffness of finer geomaterials have not been adopted, with the consequence that their stiffnesses are poorly defined. In a series of tests on a UK railway ballast, simple adaptations were made to existing local strain measuring systems to account for the larger particle sizes. The study showed that the small-strain stiffnesses are different in second loading compared to virgin loading, but multiple cycles had little further effect on the stiffness. The large particle size was found rarely to have any detrimental effect on the quality of the strain measurements and the two independent measurements of axial strain taken at diametrically opposite locations were generally as consistent as for finer grained soils. As for other soils, the 'external' measurements of strain across the apparatus platens were of little use in determining stiffness. The presence of water did not have a significant effect on the behaviour, and this was confirmed by inter-particle loading tests on single particle contacts. Despite the use of lubricated end platens, there was a significant barrelling of the sample at large shear strains so that the internal measurement of the volumetric change diverged from the external measurement at large strains. The very small volumetric strains that occurred during isotropic loading meant that each sample could only be used to obtain one measurement of the virgin loading stiffness. [ABSTRACT FROM AUTHOR]
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- 2024
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23. Numerical investigation of fibre-optic sensing for sinkhole detection.
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Della Ragione, Gianluigi, Bilotta, Emilio, Xu, Xiaomin, Da silva burke, Talia S., Möller, Tobias, and Abadie, Christelle n.
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SINKHOLES , *SOIL particles , *GEOTECHNICAL engineering , *LAND subsidence , *SOILS - Abstract
This paper forms part of the SINEW (sinkhole early warning) project and continues the work conducted by Möller and co-workers in 2022, where 1g experiments demonstrated the feasibility of using distributed fibre-optic sensing (DFOS) for sinkhole early warning. Their experimental campaign highlighted an order of magnitude difference in the strain between the soil and the cable that remains unexplained and weakens confidence in the technology and/or the experimental method. This paper uses three-dimensional finite-element analyses to examine further this discrepancy and the soil–cable interface. The results support the experimental findings and demonstrate that the DFOS signature strain profile is induced by the horizontal movement of the ground, and enhanced when sufficient coupling at the soil–cable interface is achieved. This result holds when modelling is scaled to realistic confining pressure, and its significance is twofold. First, this needs to be accounted for in the DFOS laying technique. Second, particles of cohesionless soils undergo relatively high horizontal displacement away from the centre of the sinkhole, and this means that DFOS cables are able to detect subsidence away from the centre of the sinkhole. The paper illustrates this result and the signature strain profile expected in this case. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Analytical Solution for the Steady Seepage Field of a Circular Cofferdam in Nonhomogeneous Layered Soil.
- Author
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He, Zhen, Huang, Juan, Yu, Jun, Li, Dong-Kai, Zhang, Zhi-Zhong, and Zhang, Li
- Subjects
- *
ANALYTICAL solutions , *INTEGRAL equations , *BESSEL functions , *SOIL depth , *SOILS - Abstract
The analytical solution of the steady-state seepage field of a circular cofferdam in nonhomogeneous layered soil of finite depth is derived, including the head function, exit hydraulic gradient formula, and seepage flow formula. The head function is obtained by dividing the circular cofferdam seepage field into regions and then using the separated variable method combined with the Sturm–Liouville theory, and the unknown coefficients in the head function are determined by constructing a system of equations through the integral transformation of the Bessel function. Based on the head function, an analytical equation is also given for the exit hydraulic gradient and seepage flow. The accuracy of the proposed analytical solution is verified by a comparison with numerical results as well as with the results of other methods. The proposed analytical solution is a display analytical solution without singularities and can be used as an effective tool for the analysis of circular cofferdam seepage problems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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25. Unified Modeling for the Simple Shear Behavior of Clay and Sand Accounting for Principal Stress Rotations.
- Author
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Yuan, Ran, Yu, Hai-Hong, and Wang, Xiao-Wen
- Subjects
- *
CLAY , *SOILS , *SAND , *ROTATIONAL motion , *PLASTICS , *SAND waves - Abstract
Mechanical response of soils under simple shear conditions has long been a subject of significant interest in the field of geomechanics. When subjected to simple shear loading, soils experience rotations of the principal stress directions. To provide a unified description for the simple shear behavior of clay and sand, this paper proposes a novel critical state model that accounts for the influence of principal stress rotation (PSR), based on the unified critical state model for overconsolidated clay and sand with subloading surface (CASM-S). The novelty of the newly proposed model, which is named as CASM-SP, lies in its ability to consider the influence of direction of the stress increment when establishing the plastic flow rule that is suitable for both clay and sand. Therefore, the model can capture the mechanical response of soils resulting from the PSR loading mechanism, such as noncoaxial behaviors. Then, the newly proposed model is validated through the comparisons with a series of experimental data of clay and sand under both drained and undrained simple shear conditions. Results predicted by the CASM-SP model agree well with those from the experiments, demonstrating that CASM-SP can reasonably describe the simple shear behavior of both clay and sand. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. The effect of thermal treatment on the transformation and transportation of arsenic and cadmium in soil.
- Author
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Zhou, Fengping, Guo, Meina, Zhao, Nan, Xu, Qianting, Zhao, Tuokun, Zhang, Weihua, and Qiu, Rongliang
- Subjects
- *
ARSENIC , *BOILING-points , *HIGH temperatures , *SOILS , *SOIL acidity , *VOLATILE organic compounds , *CADMIUM - Abstract
• Thermal treatment alters soil properties, and then influences Cd and As transformation. • The calcinating process exhibits distinct volatilization behaviors for Cd and As. • TCLP-extractable Cd and As contents demonstrate adverse leaching tendencies following the calcination. Thermal treatment can effectively decontaminate soils but alter their properties. Previous research mainly focused on volatile organic compounds and metals, i.e. Hg, neglecting non-volatile metal(loid)s. This study aimed to investigate Cd and As transformation during aerobic and anaerobic calcination. The results showed that both aerobic and anaerobic calcination increased soil pH by reducing soil organic matter (SOM) content, which also influenced the cation exchange capacity (CEC) and the leaching behavior of Cd and As in the soil. The total concentrations of Cd and As in the calcined soils varied depending on the calcination temperature and atmosphere. When the aerobic calcination temperature exceeded 700 °C, Cd volatilized as CdCl 2 , while anaerobic calcination at relatively low temperatures (600 °C) involved reductive reactions, resulting in the formation of metallic Cd with a lower boiling point. Similarly, As volatilized at 800 °C aerobically and 600 °C anaerobically. The formation of As-based minerals, particularly Ca 3 (AsO 4) 2 , hindered its gasification, whereas anaerobic calcination promoted volatilization efficiency through the generation of C-As(III) based gaseous components with lower boiling points. Contrasting trends were observed in the TCLP-extractable Cd and As contents of the calcined soils. Over 70% of TCLP-extractable Cd contents were suppressed after thermal treatment, attributed to the elevated pH and reduced CEC of the soil, as well as volatilization. However, TCLP-extractable As contents increased with elevated temperatures, likely due to the desorption of AsO 4 3− and re-adsorption of gaseous As 2 O 3 during cooling. These findings have implications for assessing the environmental impact of thermal treatment and provide insights for remediation strategies concerning Cd and As-contaminated soils. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. 稻田土壤中病毒多样性研究.
- Author
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刘泽锟, 黄士轩, and 杨美艳
- Subjects
PADDY fields ,ENZYMES ,SOILS - Published
- 2024
- Full Text
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28. 不同坡位柑橘园土壤团聚体矿物结合态有机碳矿化特征.
- Author
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唐开钊, 张君耀, 吴 聪, 王 帅, 廖文娟, 尹力初, 周卫军, and 崔浩杰
- Subjects
SOIL structure ,MINERALIZATION ,CITRUS ,SOILS ,ORCHARDS - Published
- 2024
- Full Text
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29. 种植年限对枳壳根际微生物群落和土壤性质的影响.
- Author
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吴微微, 韩 雪, 王继朋, 孙年喜, and 李 勇
- Subjects
NUCLEOTIDE sequencing ,MICROBIAL communities ,SOILS - Published
- 2024
- Full Text
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30. Deciphering the Driving Mechanism and Regulatory Strategies of Antibiotic Resistance Genes Transmission in Lead-Contaminated Soil Microbial Communities by Multiple Remediation Methods.
- Author
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Wang, Yafei, Yu, Hang, Meng, Lingwei, Cao, Yuhui, Dong, Zhihao, Huang, Yushan, Zhu, Yimin, Ma, Qiao, Liu, Xiaonan, and Li, Wei
- Subjects
SOIL remediation ,DRUG resistance in bacteria ,GENES ,SOILS ,MAGNESIUM oxide - Abstract
Pb-contaminated soil poses inherent risks for the spread of antibiotic resistance genes (ARGs). However, few reports have investigated the distribution of lead resistance genes (LRGs), particularly their role in ARGs dynamics during Pb-contaminated soil remediation. This study explored the mechanisms driving ARGs variation under different remediation strategies. The results indicated that an increase in the total abundance of ARGs after applying montmorillonite (Imvite), the composite remediation agents of MgO and Ca(H
2 PO4 )2 (MgO-Ca(H2 PO4 )2 ), and the composite remediation agents of montmorillonite, MgO, and Ca(H2 PO4 )2 (Imvite-MgO-Ca(H2 PO4 )2 ). Bioelectrochemical systems (BES) effectively reduced ARGs abundance, and when combined with Imvite-MgO-Ca(H2 PO4 )2 , lowered the risk of ARGs proliferation linked to antibiotic deactivation. Changes in Pb concentration and pH reshaped microbial communities, impacting both LRGs and ARGs. To reduce the risk of ARGs proliferation and transmission during, various control strategies, such as modifying Pb stress, adjusting pH, and manipulating microbial community structure, have been proposed. The study provided theoretical foundation and practical strategies for controlling ARGs dissemination during the remediation of heavy metal-contaminated soil. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
31. Study on Frost Heave and Thaw Settlement Characteristics of Sanya Estuary Channel Soil Layer.
- Author
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Wu, Xiuwen, Hu, Jun, Shi, Junxin, Xiang, Hui, and Xia, Jiangtao
- Subjects
FROST heaving ,CLAY ,THAWING ,SOILS ,MELTING - Abstract
In order to explore the frost heave and thaw settlement characteristics of soil layers in the Sanya Estuary Channel Project, the frost heave rate and thaw settlement coefficient of gravel sand, fine sand, silty clay, and clay are obtained. The most unfavorable soil layers are then compared and analyzed. The variation law of frost heave and thaw settlement performance of the most unfavorable soil layer under different water content is studied. The results are as follows: (1) The freezing stage of the passage through the typical soil layer is divided into four stages: frost shrinkage, rapid frost heave, slow frost heave, and frost heave stability. The melting stage is divided into three stages: slow thaw settlement, rapid thaw settlement, and thaw settlement stability. (2) The most unfavorable soil layer in the typical soil layer of the Sanya Estuary Channel Project is silty clay, with a frost heave rate and thaw settlement coefficient of 4.51% and 5.88% at −28 °C. (3) The frost heave and thaw settlement performance of the most unfavorable soil layer is linearly related to water content. The larger the water content, the greater the frost heave rate and thaw settlement coefficient, and the more prone to damage. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Rammed Earth Techniques in China and the Mediterranean Area: A Comparative Analysis.
- Author
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Qi, Zhou, Lopez-Manzanares, Fernando Vegas, Mileto, Camilla, and Trizio, Francesca
- Subjects
COMPARATIVE studies ,SOILS - Abstract
Rammed earth techniques have a long history and are widely used in the Mediterranean and China. These traditional techniques developed independently in the two regions, producing differences and similarities. Tools and materials as two essential aspects are compared in this paper. For ease of movement and secure fixing, formworks comprise forms, end-stops, and retaining devices. The latter determines how the formwork is used. The formwork size represents the main difference and influences various aspects. Although the choice of the earth for construction is similar, the different local soil components and materials constitute essential differences in reinforcing rammed earth in the two areas. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Effects of moisture content and soil suction on the permanent deformation of tropical subgrade soils: experimental investigations and modelling.
- Author
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dos Santos, Thaís Aquino, Pinheiro, Rinaldo José Barbosa, and Specht, Luciano Pivoto
- Subjects
DEFORMATIONS (Mechanics) ,SOIL-Water Balance Model ,MOISTURE content of trees ,SOILS ,COMBINATORIAL designs & configurations - Abstract
This study presents the effects of moisture variation and the influence of matric suction on the permanent deformation (PD) of three tropical soils with different geological-geotechnical characteristics used in road subgrades in southern Brazil. The experimental programme consisted in determining the soil-water characteristic curves and in dynamic triaxial tests to obtain the PD in different compaction and post-compaction moisture contents. The variation of compaction moisture content caused microstructural changes, influencing the plastic behaviour of soils: the higher the initial moisture content, the greater their accumulated permanent deformations. As expected, the post-compaction moisture variation (wetting process) tended to increase the plastic deformation of materials, evidencing the influence of the suction variation on the performance of the soils studied. In addition, matric suction proved to be the best variable to represent the effects of moisture variation on the plastic behaviour of soils subjected to cyclic loading. Thus, a PD prediction model for tropical soils with the inclusion of this parameter was proposed. The model proved to be highly predictive and may become an important tool to be incorporated into current mechanistic-empirical design methods. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Seismic response of a mid-story isolated stilted structure in mountainous areas.
- Author
-
Li, Jianhua and Liu, Dewen
- Subjects
- *
SEISMIC response , *STRUCTURAL dynamics , *SLOPES (Soil mechanics) , *EARTHQUAKES , *SOILS - Abstract
Research on the SSI effect on flat sites has yielded many valuable conclusions. However, current research on the impacts of various special local terrains on structural dynamics remains limited. For mountainous areas, it is common to construct houses in a multi-step, climbing, and laterally staggered architectural form that follows the mountain terrain. Only through the analysis of the combined action of the upper and lower parts can the seismic performance of this type of structural form be better revealed; considering the influence of SSI effects will be closer to the actual seismic effects. Therefore, to identify the damage factors of the mid-story isolated stilted structures under earthquakes and provide optimized design plans for the structures, six models are established considering three slopes and two types of foundations based on the engineering case in Chongqing, China. Through the elastic-plastic time-history analysis under earthquakes in the down and transverse-slope directions, concludes, compared with not considering SSI, the seismic response of the mid-story isolated stilted structures considering SSI in mountainous areas is amplified. With the increase of the mountain slope, the seismic response of the structures considering SSI increases, and the amplification coefficients are between 1–1.8. The amplification coefficients of the structures without SSI are concentrated around 1, which is less influenced by the slope. The damage to the stilted isolated layer is mainly concentrated in the column and the beam end, and the maximum seismic response appears in the short columns. The foundation soil stress increases with the increase of the mountain slope. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Diverse methodologies of care: Thinking with and practising (soil) in situated, affective and enactive ways.
- Author
-
Sharp, Emma L., Yee, Kenzi, Makey, Leane, and Fisher, Karen
- Subjects
- *
REAL property sales & prices , *VALUATION of real property , *FOOD production , *SOILS , *AFFECT (Psychology) - Abstract
This research article outlines a provocation for diverse and experimentally open, situated approaches to exploring care and caring. The diversely positioned authors discuss this idea using the subject of soil, in the place and context of Aotearoa New Zealand. Little is known about the diversity of ways that everyday people value, or, have caring relationships for/with soil, among a plethora of research that positions soil ‘care’ around, for example, commercial food production, waste‐sinking, or property land value. To study diverse care in relation to soil, as with many relational subjects, requires equivalent diversity in the ways in which we might explore it. Here we outline the basis for diverse, situated methodologies that necessarily lead to a diversity of methods. This paper looks at the methodological imperatives that lead to exploring care, and discusses a variety of methods that generate different forms of ‘data’ with different forms of representation of that care. We observe that to holistically observe care relations with soil requires a diversity of methodologies, inherently ontological and epistemological – worldmaking. We discuss situated and enactive, affective approaches of Kaupapa Māori enquiry, monitoring and arts‐based approaches to ‘measure’ soil care taking place, in place, and contextualise this with our own author positionality. We discuss this suite of experimental, reflexive, affective and responsive ways to measure soil care that are contingent on that being cared about, for, with and by, and which reciprocally give care. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Artificial ground freezing for underground construction - a brief review of the theory, practice and challenge.
- Author
-
Mao, Huan, Huang, Jie, and Johnson, Drew W.
- Subjects
UNDERGROUND construction ,FREEZING ,EXCAVATION ,SOILS - Abstract
Since Artificial ground Freezing (AGF) appeared in the 1880s in the mining sector in Europe, it has been used for various construction applications worldwide. In recent years, it has been increasingly popular in urban projects due to its versatility and applicability to complicated site conditions. So far, it has been used to stabilize substrata to nearly 1,000 m below the ground surface, which is considered not possible for many other ground improvement technologies. Due to the growth in field applications, the practice and theories related to AGF have become more mature in the most recent two decades. The improvement in understanding of this topic is a result of lessons that have been learned through numerous projects, as well as a variety of comprehensive studies that have been completed. This paper reviews the existing practice, the recent development on AGF and the challenges of AGF. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Generalized tetanus complicated with Takotsubo-cardiomyopathy in a septuagenarian following a laceration injury with soil contamination – a case report.
- Author
-
Bandapaati, Sareesh, Mitrakrishnan, Rayno Navinan, Islam, Mazharul, and Memon, Usman
- Subjects
- *
TETANUS treatment , *HEART failure treatment , *MICROBIOLOGY of wounds , *SOILS , *TETANUS , *TAKOTSUBO cardiomyopathy , *HEART failure , *WOUND infections , *TRAUMATOLOGY diagnosis , *ENVIRONMENTAL exposure , *ARTIFICIAL respiration , *WOUND care , *KNEE injuries , *ACCIDENTAL falls , *CRITICAL care medicine , *CARDIAC rehabilitation , *TRISMUS , *INFECTIOUS disease transmission , *DISEASE complications , *SYMPTOMS , *OLD age - Abstract
Background: Tetanus is a clinical rarity due to the successful globally adopted childhood vaccination programme. The rising elderly population in the United Kingdom creates a subset of individuals whom are prone to develop Tetanus as they preceded this vaccination drive. Case summary: A 76 year old Caucasian lady presented with a soil contaminated laceration injury on her knee following a fall. Though she received urgent assessment and wound care, the relevance of the injury in the backdrop of her age was not appreciated and her tetanus post exposure prophylaxis was overlooked. She readmitted seeking further management 1 week later with an infected wound with Trismus and clinical features favoring Generalized tetanus. During her stay she developed Takotsubo-cardiomyopathy with congestive cardiac failure and required prolonged care in the intensive unit with mechanical ventilation and rehabilitation before being discharged home. Conclusion: First contact physicians should have a greater appreciation of the types of injuries and at-risk individuals who are more prone to develop tetanus upon exposure to ensure early and appropriate identification. There should be greater situational awareness with regard to the elderly in view of their heightened risk of development of tetanus specially those born before the vaccination drive. Knowledge regarding post exposure prophylaxis measures for tetanus should be regularly updated using local guidance to ensure awareness, so as to despite its rarity Tetanus remains an adequately appreciated disease. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. The mechanism of arsenic behaviour in the soil-plant system and its interaction with biogenic macroelements of plants under conditions of toxic stress.
- Author
-
Belogolova, Galina A., Baenguev, Boris A., Chuparina, Elena V., Pastukhov, Mikhail V., Prosekin, Sergey N., and Sokolnikova, Yulia V.
- Subjects
- *
ARSENIC compounds , *CHEMICAL speciation , *PHYTOTOXICITY , *ARSENIC , *POLLUTION , *SALT - Abstract
The mobility of arsenic compounds in the soil-plant system and its interaction with biogenic macroelements K, P, Ca, Mg, Si, S, Na in plants under conditions of toxic stress have been studied. This is illustrated by the wheatgrass
Elytrigia repens . It has been established that the root system is responsible for protecting the aerial part of wheatgrass from excess arsenic, and it is of great importance for phytostabilisation of arsenic pollution therefore indicating the increased tolerance of this plant. The intensity of As accumulation in plants depends on its speciation in the soil. Antagonism of the main essential elements (K, P) to the accumulation of As in wheatgrass shoots is observed. It can lead to disruption of metabolic processes in plant cells. It has been shown that changes in the K+/Na + values may lead to violation of osmotic processes in the aerial plant organs and contribute to their degradation not only under salt stress but also under the influence of higher concentrations of As in the plants. In areas intensively contaminated with arsenic, a decrease in the K/Na value in the above-ground organs of wheatgrass can be used as a criterion for the degree of phytotoxicity. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
39. Optimization of high-precision Bekker test plate structure for rarefied soils–example of deep-sea subsoils.
- Author
-
Wang, Teng, Tang, Peng, Xie, Baoqi, and Ma, Wenbo
- Subjects
- *
SOIL compaction , *BEARING capacity of soils , *COMPRESSION loads , *SUBSOILS , *SOILS - Abstract
AbstractThe Bekker apparatus is an important tool for measuring soil bearing capacity; however, it is not entirely suitable for deep-sea sediments, and the size of the loading plate can affect the accuracy of the Bekker bearing parameters. This paper employs the Coupled Eulerian-Lagrangian (CEL) method to explore how different conditions impact Bekker bearing parameters. As the size of the loading plate gradually increases, the soil compression mechanism and load path reach a relatively stable state, leading to the stabilization of Bekker bearing parameters. The study proposes a range of plate sizes for deep-sea soils with varying strengths, noting that the physical mechanisms of low-strength soils are relatively simple, making them more consistent with the ideal conditions described by Bekker’s theory. Furthermore, an analysis of the relationship between Bekker bearing parameters and penetration depth reveals that the parameters corresponding to different strength soils vary almost parallel with depth. This is attributed to the same settlement path, where the distribution of loads and the geometrical shapes of the supporting structures remain unchanged, resulting in a similar trend in the variation of Bekker parameters. The research findings provide a theoretical basis for analyzing the bearing capacity characteristics of soft deep-sea soils. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. New records of soil mites from Pakistan, with description of a new species (Acari: Laelapidae).
- Author
-
Khan, Ahmad Kamran, Halliday, Bruce, and Bashir, Muhammad Hamid
- Subjects
- *
PARASITIFORMES , *BIOGEOGRAPHY , *MITES , *SPECIES , *SOILS - Abstract
This paper records six species and five genera of mites in the family Laelapidae from soil in Punjab, Pakistan. Five species are recorded from Pakistan for the first time – Euandrolaelaps karawaiewi (Berlese, 1904), Gaeolaelaps minor (Costa, 1968), Gymnolaelaps kabitae Bhattacharyya, 1968, Ololaelaps translineatus (Barilo, 1991), and Stratiolaelaps scimitus (Womersley, 1956). Cosmolaelaps lutosus sp. nov. is described as a new species. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. 脲酶诱导碳酸钙沉积 (EICP) 减小三峡库区紫色土分离能力效果.
- Author
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刘德玉, 张 伦, 夏振尧, 张文琪, 向 瑞, 高 峰, and 肖 海
- Subjects
- *
SOIL conservation , *SOIL infiltration , *SOIL erosion , *MICROSCOPY , *EXPONENTIAL functions , *CALCIUM carbonate - Abstract
The Three Gorges Reservoir Area (TGRA) has often suffered the most serious soil erosion in recent years. Soil erosion control still remains on the purple soil, the main soil type for the sloping farmland in this area. Among them, enzyme- induced carbonate precipitation (EICP) can rely on the urease enzymes to catalyze urea. Specifically, the urea can be decomposed into ammonium and carbonate anions, and then precipitated the calcium carbonate (CaCO3) with the presence of carbonate anions and external calcium sources. EICP has been proven to efficiently strengthen the soil for less infiltration, in order to restore the rock and heritage. A promising approach can be regarded to effectively control soil erosion. However, the effect of EICP on the soil detachment capacity is still far from clear, especially for the response of soil detachment to the EICP concentration and maintenance time. Therefore, this study aims to clarify the effect of EICP solution concentration and maintenance duration on the soil detachment capacity of purple soil in the Three Gorges Reservoir Area. The purple soil in the TGRA was taken as the research material. The scouring experiments were conducted under five EICP solution concentrations (0 (for control check), 0.5, 1.0, 1.5, and 2.0 mol/L) at six maintenance durations (1, 7, 15, 30, 60, and 120 d), in order to estimate the soil detachment capacity. Also, the apparent cohesion and calcium carbonate content were measured at different experiment conditions. Moreover, the SEM was employed to reveal the micro-mechanism of erosion reduction by EICP. The results indicated that the soil detachment capacity of purple soil significantly decreased with the application of EICP solution. Compared with the CK, the soil detachment capacity decreased by 19.63%-86.92%, 38.79%-89.41%, 48.13%-89.91%, and 31.78%-84.49%, respectively, at the EICP solution concentration of 0.5, 1.0, 1.5 and 2.0 mol/L, with the most pronounced effect at the concentration of 1.5 mol/L. Additionally, the soil detachment capacity decreased rapidly, whereas, the subsequent slowly decreased as maintenance duration increased. Compared with the maintenance for 1 d, the decreases at 7, 15, 30, 60, and 120 d were 19.79%-84.08%, 33.81%-87.80%, 87.27%-94.21%, 91.41%-93.18%, and 91.18%-92.77%, respectively. Moreover, the reduction amplitude in the soil detachment capacity accounted for 85.79%-92.21% of the total reduction amplitude at the maintenance duration of 7 d under the application of the EICP solution. The apparent cohesion and calcium carbonate content of purple soil showed a trend of increase followed by a decrease with the increase of EICP solution concentration. Compared with the CK, the apparent cohesion increased by 43.70%-77.43%, 58.54%-101.21%, 77.06%-135.68%, and 64.08%-87.86%, respectively, at the EICP solution concentration of 0.5, 1.0, 1.5 and 2.0 mol/L, while the calcium carbonate content increased by 10.29-17.35 times, 11.12-23.00 times, 12.00-29.59 times and 10.88-24.35 times, respectively. Additionally, the apparent cohesion increased by 10.46%-36.38%, 21.98%-46.46%, 35.12%-55.41%, 45.15%-65.49%, and 48.61%-72.76%, respectively, at the maintenance for 7, 15, 30, 60 and 120 d, compared with the maintenance for 1 d. The content of calcium carbonate increased by 54.17%-133.48%, 60.94%-134.39%, 61.98%-134.84%, 61.46%-134.84%, and 62.50%-135.29%, respectively, at the maintenance for 7, 15, 30, 60 and 120 d under the application of EICP solution, compared with the stable content in the CK. The increase amplitude in the apparent cohesion and calcium carbonate content accounted for 37.59%-59.56% and 78.26%- 98.66% of the total increase amplitude, respectively, at the maintenance duration of 7 d. Additionally, the microscopic analysis exposed that the soil detachment capacity was reduced to aggregate the calcium carbonate in the soil surface under the application of EICP solution. Furthermore, the soil detachment capacity was better described by the apparent cohesion and calcium carbonate content with an exponential function. The findings can provide theoretical guidance to promote erosion control in the application of EICP on soil detachment of purple soil in the TGRA. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. 考虑有机质含量及分解度的草炭土导热系数模型改进.
- Author
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贺元源, 何玟, 王力, 王世梅, 吕岩, 徐燕, 陈 勇, and 张先伟
- Subjects
- *
FROZEN ground , *THERMAL conductivity , *TEMPERATURE distribution , *PARTICLE size distribution , *EARTH temperature - Abstract
Soil thermal conductivity is one of the most important parameters to determine the heat transfer performance of the soil layer, leading to the ground temperature distribution, soil environment, and crop growth. The composition of organic matter is directly related to the thermal conductivity of high organic soil. However, the current model of soil thermal conductivity cannot consider the organic matter content and decomposition degree. This study aims to analyze the influence of the undisturbed turfy soil on the thermal conductivity in the different layers. Additionally, more than 10 improved models of soil thermal conductivity were proposed and then compared on the turfy soil. The results indicate that: 1) The thermal conductivity in each layer of unfrozen turfy soil was similar (0.51~0.66 W/(m∙K)). There was a significant difference in the thermal conductivity among the layers (1.00~1.62 W/(m∙K)) after freezing, indicating that the freezing altered the composition of the soil. The higher proportion of components was found with the low heat transfer performance, due to more organic matter components and pores in turfy soil. The thermal conductivity of unfrozen turfy soil was lower than that of other organic soil with higher dry density. Most water in the soil was turned into ice after freezing, indicating the greatly improved thermal conductivity. The high content of water greatly contributed to the thermal conductivity of frozen turfy soil. Furthermore, a correlation analysis was carried out between the fundamental physical properties of turfy soil and the thermal conductivity. The soil particle size distribution, organic matter content, and decomposition degree depended mainly on the thermal conductivity of unfrozen turfy soil. 2) Most prediction models of soil thermal conductivity (Campbell, Johansen, and their derived models) failed to directly consider the proportion of organic matter components in the turfy soil, leading to overestimation of the thermal conductivity of organic matter in the solid phase. Alternatively, the soil thermal conductivity model was used to consider the dry density (Nikoosokhan model) and component weight (Tian model), indicating the excellent applicability to predict turfy soil. It indirectly quantified the low performance of heat transfer in the organic matter components and pores, according to the density differences after the calculation of soil thermal conductivity. The high level of accuracy was still difficult to achieve (RMSE>0.07 W/(m∙K) for unfrozen soil; RMSE>0.28 W/(m∙K) for frozen soil). 3) According to the soil properties, the parameters were introduced to characterize the turfy soil, including organic matter content (Oc) and decomposition degree (Dd), in order to improve the model of thermal conductivity. The improved model was obtained to comprehensively consider the low dry density, high water content, and high organic matter of turfy soil. The parameters were modified to reduce the overestimation of the thermal conductivity of organic matter components. Furthermore, a better prediction (R² > 0.75) of the soil thermal conductivity model was achieved for both unfrozen and frozen turfy soil with high organic matter, in terms of applicability and accuracy. The research findings can provide a strong theoretical reference for the thermophysical properties of seasonal frozen turfy soil with high organic matter in agricultural cultivation and engineering construction. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. On evaluating the hypothesis of shape similarity between soil particle-size distribution and water retention function.
- Author
-
Lazzaro, Ugo, Mazzitelli, Caterina, Sica, Benedetto, Di Fiore, Paola, Romano, Nunzio, and Nasta, Paolo
- Subjects
- *
WATER distribution , *SOIL moisture , *VOLCANIC soils , *WATERLOGGING (Soils) , *SOILS - Abstract
Two pedotransfer functions (PTFs) are available in the literature enabling the soil water retention function (WRF) to be estimated from knowledge of the soil particle-size distribution (PSD), oven-dry soil bulk density (rb), and saturated soil water content (qs): i) the Arya and Heitman model (PTF-AH), and ii) the Mohammadi and Vanclooster model (PTF-MV). These physicoempirical PTFs rely on the hypothesis of shape similarity between PSD and WRF, and do not require the calibration of the input parameters. In the first stage, twenty-seven PSD models were evaluated using 4,128 soil samples collected in Campania (southern Italy). These models were ranked according to the root mean square residuals (RMSR), corrected Akaike information criterion (AICc), and adjusted coefficient of determination (R2adj). In the second stage, three subsets of PSD and WRF data (DS-1, DS-2, and DS-3), comprising 282 soil samples, were used to evaluate the two PTFs using the best three PSD models selected in the first stage. The hypothesis of shape similarity was assumed as acceptable only when the RMSR value was lower than the field standard deviation of the WRFs (s*), which is viewed as a tolerance threshold and computed from the physically based scaling approach proposed by Kosugi and Hopmans (1998). In the first study area (DS- 1), characterized by a fairly uniform, loamy textured volcanic soil, the PTF-AH outperformed the PTF-MV and both PTFs provided reasonable performance within the acceptance threshold (i.e., RMSR < s*). In the other two heterogeneous field sites (DS-2 and DS-3, characterized by soil textural classes that span from clay and clay-loam to loam and even sandy-loam soils), the PTF-MV (with 3% to 6% RMSR surpassing s*) outperformed the PTF-AH (with 8% to 30% RMSR surpassing s*) and the majority of RMSR values were larger than those obtained in the original studies. The mean relative error (MRE) revealed that the PTF-MV systematically underestimates the measured WRFs, whereas the PTF-AH provided negative MRE values indicating an overall overestimation. The outcomes of our study provide a critical evaluation when using calibration-free PTFs to predict WRFs over large areas [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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44. Engineered metagrating as shield from surface Rayleigh waves.
- Author
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Liu, Wenlong and Zheng, Ran
- Subjects
- *
RAYLEIGH waves , *SEISMIC waves , *METAMATERIALS , *ENGINEERING , *SOILS - Abstract
Rayleigh wave isolation using metamaterials is a research hotspot in the engineering community, yet the development of relevant mitigation methods remains an open and challenging problem. Herein, we propose a new type of metasurface, known as an engineered metagrating, which is a special metasurface buried in soil and plays a role in shielding surface Rayleigh waves. Moreover, the total omnidirectional reflection characteristics and subwavelength properties exhibited by the proposed metasurface provide a more flexible reference for surface Rayleigh wave mitigation measures in practical engineering applications. This work can open new avenues for controlling the propagation of seismic surface waves. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Using geopolymer coated and uncoated geotextile as a hybrid method to improve uplift capacity of screw piles in cohesionless soil.
- Author
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Sarici, Talha and Ozcan, Mustafa
- Subjects
COATING processes ,NUMERICAL analysis ,SCREWS ,SOILS - Abstract
In this research, experimental studies and numerical analyses were carried out to investigate how the usage of geotextile and geopolymer coated geotextile as a hybrid method changes the uplift behavior of the screw piles in cohesionless soil. In this context, traditional pile behavior, the effect of different number of helixes and embedment depths on screw piles, the mechanism of geotextile and the effects of geopolymer coating process were investigated. In addition, experimental studies were modeled by using Plaxis 3D and parametric studies were carried out after verification between the results of experimental study and numerical analysis. In the numerical analysis, a segmented helix model consisting of four 90-degree slices was developed instead of the planar helixes commonly used in the literature. For further investigation of the effectiveness of hybrid method, parameters such as improvement ratios and breakout factors were calculated. When the results obtained within the scope of the study were evaluated, the geopolymer coating process increased the bearing capacity of the geotextile by 24 % at 27 % less elongation. It was also seen that uncoated and geopolymer coated geotextile increased the screw pile performance in terms of improvement ratios by 294 % and 364 %, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Study of a New Type of Large-Diameter Multi-Disc Soil Anchor and Its Bearing Characteristics and Creep Property.
- Author
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Wang, Jiawei, Xia, Hongbing, and Hua, Jing
- Subjects
BEARING capacity of soils ,SOIL creep ,SOILS ,CONTROL groups ,MORTAR - Abstract
This paper presents a new type of large-diameter multi-disc soil anchor and its cavity-forming tool. The large-diameter multi-disc soil anchor is obtained by adopting a toothed chain, centrifuging holes to form cavities, forming multiple cavities, placing a steel strand with centering support, injecting cement mortar, and curing. In order to study the uplift bearing characteristics and creep property of the large-diameter multi-plate soil anchor, the equal-diameter soil anchor was taken as the control group. The ultimate pull-out bearing capacity, vertical displacement, axial force, anchor plate bearing load, and side friction resistance were simulated and analyzed by FLAC3D 5.0 64-bit software, and the creep property test of the anchor bolt was carried out. The results show that under the same conditions, the ultimate pulling capacity of the large-diameter multi-disc soil anchor is 125% higher than that of the same-diameter soil anchor. The vertical displacement of the large-diameter multi-disc soil anchor decreases by 51.74% compared with that of the equal-diameter soil anchor when the ultimate uplift capacity is reached. The side friction resistance of the large-diameter multi-disc soil anchor is small and its growth rate is slow. When the ultimate pulling capacity is reached, the load sharing of the anchor disc accounts for 76.54% of the total load applied. The creep rate of the large-diameter multi-plate soil anchor bolt is 0.91 mm, and the creep rate of the equal-diameter soil anchor bolt is 1.69 mm. By fitting the data, it is found that the large-diameter multi-disc soil anchor provides a method to increase the anchorage force of the soil anchor, and the research on its bearing characteristics and creep property provides a theoretical basis for the application of the soil anchor. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Face Stability Analysis for Tunnels under Steady Unsaturated Seepage and Inhomogeneity Conditions.
- Author
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Xie, Yi, Liao, Hong, and Zhou, De
- Subjects
SAFETY factor in engineering ,WATERLOGGING (Soils) ,TUNNELS ,COHESION ,SOILS - Abstract
In the field of tunnels, the stability of tunnel faces is generally considered in dry, saturated and homogeneous soils. However, the actual condition of some soils has been found to be inhomogeneous, with unsaturated seepage. In this paper, an analytical method is applied to estimate the safety factor when the supporting force at the tunnel face is zero under steady unsaturated seepage and inhomogeneous conditions. This method combines kinematic limit analysis techniques with strength reduction techniques; an efficient stress formulation utilizing suction stress is employed to determine the apparent cohesive force to obtain the solution of the steady unsaturated seepage problem, and indicators of soil inhomogeneity are attributed to the effect on cohesion. A 3D log-spiral collapse mechanism is used to find the zero supporting pressure and determine the safety factor through an iterative method. This paper analyzes the effect of variations in the unsaturated parameters, inhomogeneity parameters and tunnel dimensional parameters on the stability of the tunnel face. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. A comparison between a proposed preconsolidated presheared flush (P.P.F) testing procedure and flush procedure to measure the drained residual strength.
- Author
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Djaafri, Djamel Eddine and Nouaouria, Mohamed Salah
- Subjects
FRICTION ,COST effectiveness ,SOILS ,DESIGN - Abstract
Due to its simple design and cost-effectiveness, Bromhead ring shear apparatus is widely used to assess the drained residual strength through various testing procedures such as single stage, preshearing, and multistage. However, when compared to back-calculated case histories, values obtained through these testing procedures were found to be higher due to wall friction. To address this, Stark and Vettel (Geotech Test J 15:24–32, 1992) have introduced the "Flush testing procedure" which involves adding remolded soil to the specimen and reconsolidate it, in order to minimize the wall friction. Although the procedure yielded satisfactory results, it is more time-consuming. This paper presents a comparison between a proposed preconsolidated presheared flush (P.P.F) and flush testing procedures. The test results showed that this procedure has successfully minimized the effect of wall friction, providing values lower than those obtained using the flush procedure in shorter time. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Numerical investigation of pile foundation systems employing an enhanced embedded finite element.
- Author
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Granitzer, Andreas-Nizar, Felic, Haris, Leo, Johannes, Stastny, Alexander, Tschuchnigg, Franz, Vrettos, Christos, and Zhou, Haizuo
- Subjects
BUILDING foundations ,COUPLING schemes ,BOUNDARY value problems ,ENGINEERING ,SOILS - Abstract
The design of large-scale pile foundation systems is routinely assisted by finite element simulations. To a large extent, both the modeling and the computational effort of such analyses are governed by the adopted pile modeling technique. The traditional approach to this problem fully resolves the pile and soil domain employing solid elements, resulting in considerable meshing constraints and high simulation runtimes that may be regarded as unbearable for many practical purposes. As an attractive alternative to circumvent these obstacles, embedded FE models have become increasingly popular in solving this modeling task, mainly due to their flexible meshing procedure and significantly enhanced runtime efficiency. In a preceding contribution, the authors have proposed an extended formulation that provides a rigorous framework to capture soilstructure interaction effects at the physical soil-pile contacts. As a key feature, the implemented combined soil-pile coupling scheme explicitly accounts for endpoint interaction. However, validation studies have been constrained to single pile analyses to date. The present work expands this validation scope to largescale boundary value problems involving multiple piles and investigates the model performance based on three different case studies. The results are compared to both, measurements and numerical benchmark solutions and provide exclusive insight into the numerical fidelity of the developed embedded FE model, with a view to increasing its potential for take-up in engineering practice. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Chemical, ecotoxicological characteristics, environmental fate, and treatment methods applied to cyanide-containing wastewater.
- Author
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Vaca-Escobar, Katherine, Arregui-Almeida, David, and Espinoza-Montero, Patricio
- Subjects
BIOGEOCHEMICAL cycles ,WASTE recycling ,CYANIDES ,SEWAGE ,SOILS - Abstract
The main chemical, ecotoxicological, and environmental fate characteristics of cyanide, along with its treatment methods for cyanide-contaminated wastewater, were thoroughly examined. A global biogeochemical cycle of cyanide is proposed, covering the key physicochemical processes occurring in aqueous, soil, and atmospheric environments. The principles, advantages, and disadvantages of various treatment methods—including chemical, physicochemical, electrochemical, photochemical, and biological approaches—are evaluated. Finally, the feasibility of reusing cyanide waste is explored. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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