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Clarifying the correlation between macro–microscopic granular parameters and establishing effective parameter calibration methods for determining granular microparameters is of great importance for numerical simulations of granular flows. Currently, there is a gap in the systematic study of small particles, using sandy soil as an example, and the development of rational and effective calibration methods. Through inter-particle friction experiments, particle–wall friction experiments, uniaxial compression experiments and numerical simulations, we studied the relationship between macroscopic and microscopic parameters. Based on these studies, appropriate empirical formulas were proposed, and based on the correlation of macroscopic and microscopic parameters, a method for calibrating microscopic parameters was presented. This approach uses empirical formulas for macroscopic and microscopic parameters in combination with the constraints imposed by the granular stiffness coefficient to calibrate granular parameters. This study provides a systematic process framework for the calibration of microscopic parameters of small particles, standardizing the parameter calibration process and improving both efficiency and quality. [ABSTRACT FROM AUTHOR]

The research on the concrete structure built with self-healing materials brings inspiration to increase the safety and sustainability of underground structures in the whole life cycle. The utilization of microencapsulated healing agents in self-healing concrete has demonstrated efficacy in the repair of microcracks within concrete structures. Nevertheless, there exists a dearth of effective methodologies for assessing the impact of microcapsule parameters on the mechanical properties of self-healing concrete. This study introduces an innovative three-dimensional micromechanical model that can be utilized to analyze the micromechanical response of microencapsulated self-healing concrete under tensile loading conditions. The 3D micromechanical model is accomplished through the utilization of the elastic secant compliance tensor. Subsequently, a comprehensive examination is undertaken to analyze the progression of damage-healing in self-healing concrete incorporating microcapsules. Finally, a parametric investigation is conducted to elucidate the impact of the micro-parameters on the mechanical behavior of self-healing concrete. The present discovery holds significant implications for the development of microencapsulated self-healing concrete for underground structures, particularly in terms of establishing appropriate parameters. [ABSTRACT FROM AUTHOR]

Revealing geological environment resilience (GER) under seawater intrusion (SWI) hazards is a prerequisite for solving groundwater resource depletion, land salinization, and ecological degradation in coastal cities. This study applies the resilience design approach based on urban complex adaptive systems theory to understand the impact of SWI on the geological environment. Taking SWI as the research object, the GER evaluation method under SWI disaster was established by selecting five elastic indexes: disturbance intensity, geological environment vulnerability, stress resistance, recovery, and adaptability. This method is used to evaluate the GER level of the coastal areas of Shenzhen in recent years under the impact of SWI hazards. The study found that there is a negative correlation between the intensity of disturbance and precipitation amount. The vulnerability is greater the closer the distance to the coastline and the shallower the depth of bedrock burial. Resistance is composed of early warning ability and disaster prevention ability, and the result is 10.07, which belongs to the medium level. The recovery is 1.49, which is at a relatively high level, indicating a high capacity for restoration ability. The adaptability increased from 3.03 to 3.13, so that the area of seawater intrusion is becoming smaller. GER is affected by precipitation amount and depth of bedrock burial; the greater the precipitation and the shallower the bedrock burial, the lower the GER. Precipitation amount significantly impacts the SWI situation in the eastern coastal area of Shenzhen. In the central region, the impact of precipitation on GER is less significant. However, in the western region, the depth of bedrock burial primarily affects GER. Compared to completely weathered granite, Pleistocene fluvial plain sediments are more susceptible to SWI effects in freshwater environments. This study contributes to a deeper understanding of the impact of SWI on the geological environment in coastal areas, providing decision-makers with the necessary knowledge to develop targeted and effective governance and prevention strategies. [ABSTRACT FROM AUTHOR]

A nonlinear (3 + 1) -dimensional nonlinear Geng equation that can be utilized to explain the dynamics of shallow-water waves in fluids is given special attention. Various wave solutions are produced with the aid of the Hirota bilinear and Cole–Hopf transformation techniques. By selecting the appropriate polynomial function and implementing the distinct transformations in bilinear form, bright lump waves, dark lump waves, and rogue waves (RWs) are generated. A positive quadratic transformation and cosine function are combined in Hirota bilinear form to evaluate the RW solutions. Typically, RWs have crests that are noticeably higher than those of surrounding waves. These waves are also known as killer, freak, or monster waves. The lump periodic solutions (LPSs) are obtained using a combination of the cosine and positive quadratic functions. The lump-one stripe solutions are computed by using a mix of positive quadratic and exponential transformations to the governing equation. The lump two-stripe solutions are obtained by using a mix of positive quadratic and exponential transformations to the governing equation. The interactional solutions of lump, kink, and periodic wave solutions are obtained. Additionally, mixed solutions with butterfly waves, X-waves and lump waves are computed. The Ma breather (MB), Kuznetsov–Ma breather (KMB), and generalized breathers GBs are generated. Furthermore, solitary wave solution is obtained and a relation for energy of the wave via ansatz function technique. [ABSTRACT FROM AUTHOR]

During the operation of the Salt Cavern Flow Battery (SCFB) system, the rock surrounding a salt cavern is subjected to erosion by the electrolyte. To study the creep characteristics of electrolyte-bearing salt rock under long-term triaxial cyclic loading in SCFB, a triaxial creep experiment with a cycle period of 1 day was conducted. The results indicated that, when not subjected to failure, the axial stress-strain curve of electrolyte-bearing sample undergoes only two phases of "sparse-dense", entering dense phase approximately 4 cycles earlier than that of sample without electrolyte. Under the same stress conditions, the strain generated in electrolyte-bearing salt rock surpasses that of sample without electrolyte, demonstrating an initial rapid increase followed by a gradual stabilization trend. The stress-strain curve of electrolyte-bearing sample in a single cycle can be divided into six stages. The number of cycles has almost no effect on the axial strain in stages I, IV, V and VI, and the axial strain in stages IV and VI is basically 0. Additionally, the elastic deformation generated in stage I is basically recovered in stage V. The strain in stage II gradually decreases and disappears in the 4th cycle, which is 13 cycles earlier than that of the sample without electrolyte. The creep rate of electrolyte-bearing sample shows a trend of "gradual decrease—basically stabilization" as the number of cycles increases, and the creep experiment contains only the decay creep stage and steady creep stage. Irreversible deformation of electrolyte-bearing sample exhibits a gradual decrease followed by stabilization with increasing number of cycles. The research findings hold significant implications for the stability analysis of SCFB systems. [ABSTRACT FROM AUTHOR]

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To enhance our understanding of soil behavior at critical states, considering that natural soil is composed of granular matter, a quasi-static inertia number taking soil compaction into account is proposed. In analyzing classical triaxial test data of soil, the scaling law of quasi-statically deforming grains at the critical state is explored; a simple linear relationship is found between the coefficient of friction and the proposed number. This scaling law describes quantitatively the influence of initial compaction, shear rate, confining pressure, and particle size on the frictional strength of granular soils when they reach the critical state. The number proposed is employed to describe the scaling of volumetric behavior of granular soils undergoing quasi-static deformation. The difference between the particle volume fraction at the critical state and that at the initial compacted state is also found to be linearly correlated with the quasi-static inertia number, for soil at the critical state. [ABSTRACT FROM AUTHOR]

Accurate prediction of excavation deformation and stress affects the safety of excavation engineering and the surrounding environment. However, the traditional calculation method ignores the influence of soil shear action and its nonlinear deformation characteristics. Therefore, this paper proposed a coupled analytical method for braced excavation considering the continuity of soil deformation and nonlinear pile–soil interaction. A nonlinear Pasternak two-parameter foundation model was developed based on the Pasternak foundation model and nonlinear p–y curves. The control differential equations for the excavation in the critical and embedded sections were derived. Also, the numerical solutions of excavation deformation and force under different boundary conditions were obtained by the finite difference method and Newton's iteration method. Further, the excavation calculation procedure considering the construction process and nonhomogeneity of soil was suggested. Through finite-element (FE) and engineering case analyses, the traditional calculation method overestimated the excavation deformation and internal force, while the proposed methods were consistent with the measured results. Finally, the effects of soil shear stiffness and initial foundation reaction modulus on the excavation were discussed, and we found that the two parameters had more significant impact on the wall bending moment than displacement. The results provide some reference for the design calculation of braced excavation. [ABSTRACT FROM AUTHOR]

Lycorma delicatula, a globally invasive pest, has caused considerable economic losses in many countries. Determining the potential distribution range of L. delicatula is crucial for its effective management and control; however, our understanding of this species remains limited. In this study, Maxent model with occurrence records and environmental variables were fit first and then optimized by selecting the best combination of feature classes and regularization multipliers using the lowest score of corrected Akaike information criterion. Subsequently, we predicted global suitable areas for L. delicatula both currently and in the future (2041–2060, 2061–2080, and 2081–2100). The results indicated that the mean temperature of the driest quarter is the most important environmental variable limiting L. delicatula distribution. Currently, the suitable areas are concentrated in East Asia (mainly in China, South Korea, and Japan), central and eastern United States, and southern Europe. Compared with current environmental conditions, in all future climate scenarios, the number of suitable areas for L. delicatula increased. In addition, we revealed that suitable areas are likely to expand northward in the future. Our study results suggest that policymakers and governments should prioritize the development of pest management measures in suitable areas for L. delicatula, especially in high suitable areas, to control this invasive pest and minimize global economic losses. [ABSTRACT FROM AUTHOR]

A large number of experimental studies have demonstrated that the permeability and damage of rock are not constant but rather functionally dependent on stresses or stress-induced deformation. Neglecting the influence of damage and permeability evolution on rock mechanics and sealing properties can result in an overestimation of the safety and stability of underground engineering, leading to an incomplete assessment of the risks associated with surrounding rock failure. To address this, the damage and permeability evolution functions of rock under compression were derived through a combination of experimental results and theoretical analysis, unifying the relationship between porosity and permeability in both porous media flow and fractured flow. Based on this, a fluid–solid coupled seepage model considering rock damage and permeability evolution was proposed. More importantly, this model was utilized to investigate the behavior of deformation, damage, and permeability, as well as their coupled effects. The model's validity was verified by comparing its numerical results with experimental data. The analysis results show that the evolution of permeability and porosity resulted from a competitive interaction between effective mean stress and stress-induced damage. When the effective mean stress was dominant, the permeability tended to decrease; otherwise, it followed an increasing trend. The damage evolution was primarily related to stress- and pressure-induced crack growth and irreversible deformation. Additionally, the influence of the seepage pressure on the strength, damage, and permeability of the investigated rock was evaluated. The model results reveal the damage and permeability evolution of the rock under compression, which has a certain guiding significance for the stability and safety analysis of rock in underground engineering. [ABSTRACT FROM AUTHOR]

Larvae of the beetle subfamily Rutelinae are poorly described in the literature. Notably, the morphology of the larvae of Callistethus plagiicollis Fairmaire has not previously been analyzed. Here, we report for the first time that these larvae feed on the tubers and roots of Gastrodia elata Blume, an important traditional Chinese herbal medicine, which causes a reduction in the yield and economic value of G. elata. We employed scanning electron microscopy and light microscopy to investigate the morphology and occurrence regularity of egg, larvae, pupae, and adult specimens of C. plagiicollis collected from the G. elata planting base in Guizhou Province, China, with a focus on the ultrastructure of mature larvae. The results revealed one generation of C. plagiicollis per year in the study area and three instar stages of larvae. Mature larvae were identified by the following characteristics: raster without palidia with a large number of hamate setae, antennal apex containing seven sensilla basiconica, larval haptomerum containing eight sensilla styloconica and four enlarged heli, and seven longitudinally arranged stridulatory teeth on the stipes of the maxilla. The combination of scanning electron and light microscopy effectively revealed the difference between membranous and sclerotized structures, ensuring accurate identification of C. plagiicollis larvae. By determining the feeding characteristics and occurrence regularity of C. plagiicollis, this study has implications for improved pest management in G. elata crops. Research Highlights: We identified C. plagiicollis as a new pest of G. elata, a traditional Chinese medicineScanning electron and light microscopy were combined to analyze the morphology of the mature larvae of C. plagiicollis for the first timeWe determined the feeding characteristics and occurrence regularity of C. plagiicollis, which can be used to develop effective pest management strategies [ABSTRACT FROM AUTHOR]

Foundation treatment piles are crucial for enhancing the bearing capacity and stability of weak foundations and are widely utilized in construction projects. However, owing to the complexity of geological conditions, traditional construction methods fail to meet the demand for low-carbon development. To address these challenges, this study introduced a comprehensive decision-making approach that considers the impact of stratum variability on greenhouse gas (GHG) emissions and pile bearing capacity from the design phase. During the design process, the GHG emissions and bearing capacities of deep cement mixing (DCM) and high-pressure jet grouting (HPJG) piles were quantitatively assessed by analyzing the environmental and performance impacts of foundation treatment piles related to materials, transportation, and equipment usage. The results suggest that the bearing capacity of piles in shallow strata is highly susceptible to stratum variability. Using piles with a diameter of 800 mm and a length of 20 m as an example, compared with DCM piles, HPJG piles demonstrated a superior bearing capacity; however, their total GHG emissions were 6.58% higher, primarily because of the extensive use of machinery during HPJG pile construction. The GHG emissions of foundation treatment piles in shallow strata were influenced more by geological variability than those in deep strata. Sensitivity analysis revealed that the pile diameter is a critical determinant of GHG emissions and bearing capacity. Based on the bearing capacity–GHG emission optimization framework, a foundation treatment strategy that integrates overlapping and spaced pile arrangements was introduced. This innovative construction method reduced the total GHG emissions by 22.7% compared with conventional methods. These research findings contribute to low-carbon design in the construction industry. [ABSTRACT FROM AUTHOR]

The unstable mechanical behavior of soil particles during suffusion, including migration and clogging of fine particles in porous media, is prone to induce seepage catastrophes. Mechanical behavior of migratory fines and porous soils during suffusion is significantly influenced by the particle shape, which remains unclear. In this study, a coupled computational fluid dynamics and the irregular discrete element method (CFD-iDEM) framework is developed to investigate the migration and clogging mechanisms. A series of numerical simulations that consider spheres and irregular particles with different levels of aspect ratio are carried out to elucidate the microscopic origins of shape effects on clogging. Migratory fine particles are discharged from the grain inlet and enter the coarse particle skeleton by imposing a downward seepage flow. The subsequent migration and clogging phenomena and microscopic mechanisms are investigated. The results reveal that irregular particles present varying degrees of ability to develop clogging clusters, and spheres are more prone to traverse deeper into soil skeleton. The proposed CFD-iDEM method is able to reproduce macroscopic phenomena of saturated porous medium as well as to analyze microscopic origins of fluid–particle interactions, which contributes to practical guidance for engineering applications. [ABSTRACT FROM AUTHOR]

For the excavation of a shallow tunnel in soft soil, the controllable range of the support pressure is narrow due to the small area of overburdened earth pressure, and passive failure of the tunnel face can be easily induced; therefore, the soft soil must be reinforced to increase the stability of the tunnel face. In this work, numerical simulation and theoretical analysis were adopted to explore the passive failure mechanism of a tunnel face in soft ground reinforced with a soil–cement wall. First, finite element analyses were conducted to investigate the passive failure mechanism. The impact of L1 (the distance between the tunnel face and soil–cement wall) on the passive failure mode was disclosed. Three types of failure modes—the full-penetration, partial-penetration, and non-penetration modes—were identified based on the shear failure zone and variation in Pp (the limit support pressure of passive failure) with L1. Then, analytical models based on the limit equilibrium method for the three passive failure modes were established, and formulas for predicting Pp were derived. The predictions by the formulas were validated by the numerical results, and their differences were within 10%. Both indicate that Pp achieved a maximum value when L1 = 0.2D (D is the diameter of tunnel); therefore, it is reasonable to choose a distance of 0.2D between cement walls in this engineering project. [ABSTRACT FROM AUTHOR]

This paper proposes a calculation method of displacement-dependent three-dimensional (3D) earth pressure on flexible walls of the foundation pits, further considering spatial effects, layered cohesive soil, and seepage effect on earth pressure. Based on improved Coulomb's earth pressure theory, the displacement-dependent 2D earth pressure model for flexible walls is established. By introducing the concepts of spatial influence factor and plane strain ratio (PSR), the calculation model of displacement-dependent earth pressure on flexible walls of foundation pit considering spatial effects is further proposed. And the displacement-controlled solutions of earth pressure under different boundary conditions are obtained. The proposed solution is verified by numerical simulations and reported test data of foundation pit and shows good agreement. The traditional 2D earth pressure theory underestimates and overestimates the active and passive earth pressure in the corner effect area of the excavation, respectively. Through parameter analysis and discussion, the parameter effects on 3D earth pressure are ranked as soil cohesion > soil friction angle > wall friction angles. The results of the study provide an important theoretical basis for the 3D design calculation of foundation pits. [ABSTRACT FROM AUTHOR]

Pseudostellaria heterophylla, a valuable Chinese herbal medicine, is widely cultivated in China, with a planted area of 5402.7 hm2 in Shibing County, Guizhou Province. The occurrence of leaf spot disease represents a significant challenge in the production area. In this study, 30 samples of P. heterophylla exhibiting symptoms of leaf spot were collected from three primary production areas in Guizhou Province. Following isolation and purification, 51 isolates were classified into two genera based on both cultural and conidial characteristics, along with ITS sequence data. Fourteen representative strains were selected for morphological and multigene molecular identification, which revealed that these representative strains were affiliated with Alternaria arborescens species complex (SC), Alternaria tenuissima, Alternaria gaisen, and Sclerotiophoma versabilis. The isolation rates of Alternaria and Sclerotiophoma were 84.3% and 15.7%, respectively. Pathogenicity tests confirmed the identity of the causal agents and demonstrated varying levels of aggressiveness among the different genera and species of pathogens towards P. heterophylla leaves. This study marks the first identification of A. arborescens SC, A. gaisen, and S. versabilis as pathogens causing leaf spot in P. heterophylla in China. [ABSTRACT FROM AUTHOR]

Particle shape in granular materials exhibits both polydisperse and multi-level characteristics, which are intrinsically linked to the mechanical behaviours of granular materials. This study develops a particle generation framework to achieve independent control of polydisperse distributions of roundness (second level of particle shape) and roughness (third level) while preserving form (first level) distributions. In this framework, a spherical harmonic amplitude-stretching (SH amplitude-stretching) technique is proposed to precisely control the form distributions. Two decisive factors for particle roundness and roughness are introduced, and two control coefficients are designed to determine their distributions. The applicability of the proposed framework is verified by employing the generated granular assemblies with varying distributions of particle roundness and roughness into DEM simulations for granular packing and repose angle tests. The simulation results demonstrate the independent effects of polydisperse distributions of particle roundness and roughness on packing density and repose angle, providing evidence of the effectiveness of the proposed framework. [ABSTRACT FROM AUTHOR]

This study conducted experiments on dry granular mass released on an inclined flume. The periodic acceleration and deceleration of the flow, that is, the stick-slip phenomenon, was observed during the experiments. To investigate the stick-slip motion mechanism, numerical simulations were conducted with the inclusion of the shear-strengthening μ(I)-rheology into the elasto-plastic models of granular flow. The stick-slip phenomenon was captured naturally without the modification of the empirical friction law. The results revealed that the competition between the rate strengthening implemented by the μ(I)-rheology and the gravitational acceleration along the inclined plane induces stick-slips. By considering the experimental results in combination with the simulation results, the effects of the particle size, gate size opening, surface roughness, and frictional parameters of μ(I)-rheology on the stick-slip phenomenon were elucidated. [ABSTRACT FROM AUTHOR]

Flexural performance of joints is critical for prefabricated structures. This study presents a novel channel steel-bolt (CB) joint for prefabricated subway stations. Full-scale tests are carried out to investigate the flexural behavior of the CB joint under the design loads of the test-case station. In addition, a three dimensional (3D) finite element (FE) model of the CB joint is established, incorporating viscous contact to simulate the bonding and detachment behaviors of the interface between channel steel and concrete. Based on the 3D FE model, the study examines the flexural bearing mechanism and influencing factors for the flexural performance of the CB joint. The results indicate that the flexural behavior of the CB joint exhibits significant nonlinear characteristics, which can be divided into four stages. To illustrate the piecewise linearity of the bending moment-rotational angle curve, a four-stage simplified model is proposed, which is easily applicable in engineering practice. The study reveals that axial force can enhance the flexural capacity of the CB joint, while the preload of the bolt has a negligible effect. The flexural capacity of the CB joint is approximate twice the value of the designed bending moment, demonstrating that the joint is suitable for the test-case station. [ABSTRACT FROM AUTHOR]

Climate change is a prominent factor reshaping the distribution of invasive species. Metcalfa pruinosa (Say 1830) (Hemiptera: Flatidae), native to North America, has invaded other continents and poses a serious threat to various agricultural crops and the human residential environment. Understanding the distribution of M. pruinosa based on climatic conditions is a critical first step to prevent its further invasion. Therefore, based on its occurrence records and associated environmental variables, a Maxent model was developed to predict suitable areas for this species in the present and future on a global scale. The model exhibited outstanding performance, with a mean area under the receiver operating characteristic curve and true skill statistic values of 0.9329 and 0.926, respectively. The model also indicated that annual precipitation (Bio12) and max temperature of the warmest month (Bio5) were the key environmental variables limiting the distribution of M. pruinosa. Moreover, the model revealed that the current suitable area is 1.01 × 107 km2 worldwide, with southern China, southern Europe, and the eastern United States predicted to be the primary and highly suitable areas in the latter 2 regions. This area is expected to increase under future climate scenarios, mainly in the northern direction. The study's findings contribute to our understanding of climate change's impact on M. pruinosa distribution, and they will aid governments in developing appropriate pest management strategies, including global monitoring and strict quarantine measures. [ABSTRACT FROM AUTHOR]

Underground excavation is usually accompanied by complex soil-structure interaction problems in practical engineering. This paper develops a novel multi-scale approach for investigating the soil arching effect through trapdoor tests. This approach adopts the finite element method (FEM) and smoothed particle hydrodynamics (SPH) method to handle the particle-rigid body interaction in the trapdoor tests, incorporating a micromechanical 3D-H model to derive the nonlinear material response required by the SPH method. The variation of the earth pressure on the trapdoor in simulations exhibits good agreement with those of the experiments. Extensive parametric analyzes are performed to assess the effects of soil height and inter-particle friction angle on the evolution of load transfer and soil deformation. Three deformation patterns are observed under different buried conditions, including the trapezoid, the triangle, and the equal settlement pattern. Results indicate that the planes of equal settlement develop progressively with the trapdoor movement and then enter the range of experimentally observed values. Additionally, three failure mechanisms are identified that correspond to the three deformation patterns. Due to the advantages of the micromechanical model, mesoscale behavior is captured. The anisotropy of stress distribution in the plastic region is found during the arching process. [ABSTRACT FROM AUTHOR]

Horizontal jet grouting columns (HJGCs) are commonly adopted to reinforce weak ground ahead of the tunnel excavation face. However, the dynamic mechanical response of the HJGCs during tunneling remains unclear. To provide a comprehensive understanding of HJGC reinforcement mechanisms and a basis for optimal design, a mechanical shell model for the HJGCs based on the two-parameter Pasternak foundation is initially established, and the analytical solutions for deflection and internal force are derived. Furthermore, the feasibility of the proposed model is validated through comparisons with numerical simulations based on an actual project. Subsequently, the mechanical behavior of the HJGCs and the sensitivity of the design parameters on the HJGCs deformation are examined. Additionally, the influence of various factors on tunnel face stability is deliberated. The findings suggest that the analytical solution derived from the proposed model aligns closely with the results obtained through numerical simulation. The longitudinal deflection pattern of the HJGCs is categorized into the airside impact zone, excavation disturbance zone, and forward stability zone. Significantly, the transverse deflection at the vault exhibits the greatest magnitude and gradually diminishes toward the arch foot. Longitudinally, the HJGCs reinforcement effectively serves as a spatial leverage mechanism, facilitating the redistribution of pressure within the spatial domain. In addition, the sequence of the impact levels of the discussed parameters or factors is presented individually. [ABSTRACT FROM AUTHOR]

China's bamboo output is closely associated with its national economy; however, it is currently rapidly declining due to damage from the pests Anaka burmensis and Cicadella viridis. Identifying regions that are environmentally suitable for these pests is a critical step in their effective control. Therefore, in this study, we used a Maxent model to predict their current and future potential areas of distribution (2021–2040, 2041–2060, and 2061–2080) and explored changes over time using distribution data and related environmental variables. The model results demonstrates that the current potential areas of distribution of A. burmensis are predominantly concentrated in several provinces of southern and central China, such as Guizhou, Guangxi, and Hubei, whereas the current potential areas of distribution of C. viridis are primarily in many provinces across southern, central, and northeastern China. In the future, the potential distribution of A. burmensis will increase and move minimally, whereas the potential distribution of C. viridis will decrease and move considerably. The results of the present study provide vital information for predicting the spread and outbreaks of C. viridis and A. burmensis and provide a reference framework for developing management strategies to control these two pests, thereby minimizing economic loss in the bamboo industry. [ABSTRACT FROM AUTHOR]

Objective To reveal Chlamydia ttachomatis (CT) infection and its associated factors among patients attending the infertility-related clinics in Bao'an District of Shenzhen in order to develop evidence-based strategies for interventions of CT in this population. Methods From April to December 2021, patients attending four infertility-related clinics in Bao'an District of Shenzhen were invited to participate in the survey using a recruitment approach. After an informed consent was obtained, each participant provided socio-demographic and behavioral information and urine samples for CT detection using a nucleic acid assay. Logistic regression was used to determine the factors associated with CT infection. Results Among a total of 954 participants, the prevalence of CT infection was 3.56 %. The logistic analysis showed that the risk factors of CT included individuals aged younger than 25 years (OR = 3. 91,95% CI: 1.58 ~ 9.67), having junior college education (OR = 4. 33,95% CI: 1.23 ~ 15.24) and having more than 2 sexual partners in the last year (OR = 4. 25,95% CI: 1.72 ~ 10.55). The participants (74.42%) were unaware of symptoms of CT infection and 73.90% never had any prior screening for CT. Conclusions The CT infection rate is relatively high among the infertility population in Bao'an District, Shenzhen. The sexually active age, relatively low educational level, and multiple sexual partners are risk factors for CT infection. At infertility clinics, CT screening along with health education should be given to people at high risk of CT infection in order to improve the reproductive health. [ABSTRACT FROM AUTHOR]

Slit-type barriers serve as active countermeasures against debris flow. However, the dynamic interaction between debris flows and slit-type barriers is extremely complicated. To model the fluid-solid behavior of debris flows, a coupled approach of smoothed particle hydrodynamics (SPH) and discrete element method (DEM) is developed. We use the model to investigate the dynamics of how debris flows impact slit-type barriers. The proposed approach is able to simulate the embedding of arbitrarily shaped particles in viscous debris flows. A GPU acceleration technique is employed to overcome large computational costs. The approach is first validated by comparing numerical results to experimental observations for some standard conditions. Subsequently, experiments of the impact of water-enriched debris on slit-type barriers are modeled and validated. Moreover, the effects of barrier arrangement, solid volume fraction and boulder shape on debris-barrier interactions are further explored. This study analyzes the interaction between debris flows and slit-type barriers by coupled SPH–DEM and provides insight into the optimal design of barriers. [ABSTRACT FROM AUTHOR]

Crack detection plays a critical role in ensuring road safety and maintenance. Traditional, manual, and semi-automatic detection methods have proven inefficient. Nowadays, the emergence of deep learning techniques has opened up new possibilities for automatic crack detection. However, there are few methods with both localization and segmentation abilities, and most perform poorly. The consistent nature of pavement over a small mileage range gives us the opportunity to make improvements. A novel data-augmentation strategy called CrackMover, specifically tailored for crack detection methods, is proposed. Experiments demonstrate the effectiveness of CrackMover for various methods. Moreover, this paper presents a new instance segmentation method for crack detection. It adopts a redesigned backbone network and incorporates a cascade structure for the region-based convolutional network (R-CNN) part. The experimental evaluation showcases significant performance improvements achieved by these approaches in crack detection. The proposed method achieves an average precision of 33.3%, surpassing Mask R-CNN with a Residual Network 50 backbone by 8.6%, proving its effectiveness in detecting crack distress. [ABSTRACT FROM AUTHOR]

Gastrodia elata Blume, a valuable traditional Chinese medicine with significant clinical and nutritional importance, is a fungal heterotrophic orchid. We present the first report of the mitochondrial genome structure and characteristics of 3 Scarabaeidae pests affecting G. elata : Sophrops peronosporus Gu & Zhang, Anomala rufiventris Kollar & Redtenbacher, and Callistethus plagiicollis Fairmaire. Each mitogenome contained 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and a control region, with no gene rearrangements observed. All 21 tRNAs, except trnS1 that lacks a dihydrouridine, had a stable cloverleaf secondary structure. Maximum likelihood and Bayesian inference analyses based on the 13 PCGs produced 2 topologically similar phylogenetic trees, both of with high nodal support. Larvae of these Scarabaeidae pests cause substantial damage by gnawing on the tubers and roots of G. elata , leading to reduced yield and compromised quality. These findings contribute to phylogenetic studies of Scarabaeidae, expand knowledge of G. elata pests, and offer valuable reference materials for their identification and control. [ABSTRACT FROM AUTHOR]

In this paper, a resilience assessment framework for microencapsulated self-healing cementitious composites is proposed based on a micromechanical damage-healing model. A 3D micromechanical analytical model is constructed to analyze the performance evolution during the damage-healing process of self-healing concrete. The resilience assessment of microencapsulated self-healing concrete is defined by virtue of the residual stiffness, self-healing effect on stiffness and damage cumulative on stiffness, which corresponds to three main features of resilience; namely, the robustness, recoverability and adaptability. The assessment results indicate that the release of healing agents within microcapsules and healing process of extended microcracks allows the microencapsulated self-healing concrete to have higher resilience than conventional concrete. Moreover, a parameter sensitivity analysis is conducted to investigate the influence of the healing efficiency, the applied initial damage and the fracture toughness of the repaired microcrack on resilience of microencapsulated self-healing concrete. The results indicate that higher healing efficiency and applied initial damage leads to high resilience, and fracture toughness of the repaired microcrack makes less difference to the results. The findings of this paper lay a theoretical foundation for the resilience design of self-healing material layer of underground structures. [ABSTRACT FROM AUTHOR]

The structural performance of shield tunnel structures is highly susceptible to degradation under complex environmental loads, with the most common manifestation being bolt preload loss. In this study, a shield tunnel numerical simulation model was established to analyze the seismic response of shield tunnels with varying degrees of bolt preload loss. Firstly, the deformation patterns of shield tunnel structures under seismic loads were analyzed. Subsequently, ellipticity and joint opening were selected as seismic resilience assessment indicators based on the mechanical response. A seismic resilience assessment model was then established, including three states: normal state, affected state, and recovered state. The results show a direct relationship between the recovery capacity of tunnel structures and the initial performance of the lining structure, as well as the magnitude of the load. The lower the degree of structure degradation, the greater the structural recovery capacity. Additionally, there is a positive correlation between residual deformation and the initial performance loss of shield tunnel structures, as well as the intensity of seismic loads. This study contributes to enriching the theoretical framework for the seismic resilience assessment of shield tunnels, which have significant implications and provide valuable references for engineering safety. [ABSTRACT FROM AUTHOR]

The apparent influence of stress states on rheological deformation should be considered in calculating consolidation behavior for natural structured soft clays. A novel nonparallel isotache model with naturally structural characteristics was developed in this study, taking into account the variation of secondary compression coefficient with stress state and collapse state of soil structure under the elastic viscoplastic framework. The proposed rheological model was used to couple the consolidation of multi-layered soft clays under various drainage conditions. The settlement solutions, degree of consolidation, and excess pore water pressure in a short time interval were derived mathematically, and the rheological consolidation solutions were programmed and calculated using a semi-analytical method. Good agreement with experimental results indicated that the model was reasonable, and the calculation method was efficient and accurate. A series of cases were presented to investigate the effects of model parameters, soil structure, and loading mode on rheological consolidation behavior. The variation law of soil parameters and state was also discussed. [ABSTRACT FROM AUTHOR]

The real-time control and prediction of attitude and moving trajectory in shield tunneling is challenging, especially in the small radius of curvature. The present study focuses on developing a method for predicting the attitude of a shield based on a new model that incorporates a wavelet transform (WT) into a random forest (RF) deep learning method. Daubechies (dbN) is selected among several wavelet bases to denoise the original tunneling parameters in the time and frequency domains, and optimal wavelet parameters for different input variables are obtained. The proposed WT–RF model was implemented and validated by a case study of the Shizimen Tunnel in Zhuhai, China. Sorted by the correlation coefficient between the input parameters and the output parameters, eight cases with different input parameter combinations were also selected for comparison. The results revealed that the developed wavelet signal denoiser-RF model can successfully predict the shield attitude parameters and that using a suitable combination of input parameters can greatly improve the prediction accuracy of the model. The number of input parameters is not a key factor for determining the prediction accuracy of the model, and adding less relevant input parameters will greatly reduce the prediction performance of the model. [ABSTRACT FROM AUTHOR]

The interaction mechanism between grouted anchor cables and the surrounding rock mass or soil are complicated and difficult to investigate using conventional monitoring technologies. This study focuses on the in-situ pullout behavior of grouted anchor cables using Brillouin Optical Time-Domain Analysis technique. A series of pullout tests were conducted on anchor cables with five different anchor lengths and three grouting methods. Distributed fiber optic sensors were used to measure the strain distribution of cable bolts from tip to top. The in-situ pullout test results show that both ultimate pullout resistance and ultimate displacement at the ultimate pullout resistance increase with anchor length. The bond strength suffers a slight variation with an increase in anchor length. Both ultimate pullout resistance and the ultimate displacement for Type-B grouting (grouting with reaming) and Type-C grouting (secondary grouting) are larger than those for Type-A grouting (one-time grouting). The shear bond strength of Type-C grouting is greater than that of Type-A grouting. Results from Gaussian functions analysis show that it is feasible to use the function to characterize the axial stress of anchor cables. Furthermore, the overall mobilized percentage η was evaluated. The anchor cables with smaller anchor lengths will result in greater η. The η for the anchor cables of 6 m reaches 92% at the last load, whereas the anchor cables of 18 m were mobilized by only 29% at the last load. The grouting method has a negligible effect on the η, increasing from 22% to 29% in process of the pullout test. [ABSTRACT FROM AUTHOR]

The degree of soil nonuniformity consolidation varies continuously with the passage of consolidation time and is accompanied by nonlinear alterations in soil parameters. Existing theoretical models often assume a constant relationship between the parameters of the two soil layers, failing to consider the effect of nonuniform consolidation. This assumption does not align with real-world conditions and can lead to significant errors in calculation results. Hence, this study aims to investigate the dynamic changes in soil undergoing nonuniform consolidation and develop a mathematical model that accounts for this phenomenon. Based on the large-strain and double-layer models, an improved consolidation model was proposed, which considers nonuniform variations in consolidation with a vertical drain and corrections to calculations under the influence of the nonlinear relationships of soil parameters. The proposed improved model was validated by comparison with field test data, and the results were compared with those of the classical model. Finally, the effects of different consolidation parameters on consolidation behavior were investigated. The research is a reliable calculation method that incorporates the dynamic nonuniform changes in consolidated soil, enabling more accurate predictions of consolidation of foundations treated by vertical drains. [ABSTRACT FROM AUTHOR]

Shield tunnels can experience preload loss in their connecting bolts during the operational phase, leading to changes in tunnel structure stiffness, which, in turn, affect the seismic performance of shield tunnels. A refined three-dimensional model of shield tunnel was established using the finite element method to study the impact of preload loss in connecting bolts on the seismic dynamic response of shield tunnels. An artificial viscoelastic boundary was used to simulate the propagation of seismic waves from an infinitely distant field. This study investigated the effects of different levels of preload loss on the seismic response of shield tunnels. In addition, the Arias intensity, which can reflect the degree of seismic impact on structures, was used to analyse the extent of damage to the tunnel. The conclusions drawn from the study are as follows: As the level of preload loss increases, the tightness of the segments during the static phase gradually deteriorates, and the maximum joint opening during the seismic loading phase continues to increase. Post-earthquake non-recoverable ellipticity and radial deformation progressively increase with an increase to preload loss level. Overall tunnel damage becomes more significant with the degree of preload loss increases depending on the Arias intensity. Preload loss leads to a decrease in the overall structural stiffness and an increase in longitudinal relative displacement. In conclusion, preload loss also affects structural failure mode and seismic performance. These research findings are of reference value for enhancing the seismic performance of shield tunnel structures and ensuring engineering safety. [ABSTRACT FROM AUTHOR]

In recent times, there has been a sharp increase in the congestion of ground transportation, the scarcity of land resources, and various disasters. Hence, there is an urgent need to find an effective and sustainable approach to transportation. The construction of an underground logistics network, where transportation activities occur beneath the surface of the ground, is anticipated to emerge as a future trend. This study aims to formulate a resilient-maximizing plan for the underground logistics network, ensuring optimal meeting of transportation demands in the aftermath of ground disasters. Accordingly, a two-stage linear programming model is established to determine the layout plan for the most resilient underground logistics network. The first phase of the model is designed to generate viable layouts for the underground logistics network, while the second phase is dedicated to evaluating the resilience of the proposed layout plan. During the evaluation of network resilience, Monte Carlo simulations are used to simulate disaster scenarios. Given the inherent complexity of the model, the traditional solver cannot efficiently solve the problem. Thus, a new hybrid heuristic algorithm is designed to obtain solutions that maximize network resilience. The results show the effectiveness of the designed algorithm and the significant improvement in network resilience achieved by numerical experiments. Moreover, sensitivity analyses are conducted to reveal the relationships between resilience and budget, as well as resilience and the capacity of underground pipelines. It has a significant impact on sustainability when making decisions regarding network planning. [ABSTRACT FROM AUTHOR]

Various adjacent construction projects are inevitably encountered during the large-scale construction of urban underground transportation. The case of a twin shield tunnel excavated below an existing multi-arch culvert bridge in close vicinity has not yet been thoroughly studied. A case of a shield tunnel excavation below an existing multi-arch culvert bridge in Foshan is presented. First, a fully coupled three-dimensional model incorporating fluid and solid interactions was established to simulate the twin shield tunnel excavation below the existing multi-arch culvert bridge in close vicinity. Subsequently, the numerical model was validated using the modified Peck empirical formula. Finally, the influence of different foundation reinforcement deformation moduli, tunnel excavation face support pressures and grouting pressures on ground deformation was discussed. The results indicate that the area most significantly affected by the excavation of the tunnel passing underneath is not within the section of the multi-arch culvert bridge after applying the foundation reinforcement design. The area most significantly impacted is concentrated as the shield tunnel commences excavation and advances beneath the location corresponding to the 1-hole of the steel corrugated pipe. The range of influence of the ground disturbance extends approximately 7 m in front of the excavation face before the tunnel passed through. The range of ground disturbance decreases to 4–6 m in front of the excavation face after the tunnel passed through. The excavation face support pressure and grouting pressure have a minor impact on the settlement of the multi-arch culvert bridge under this reinforcement design. The results provide useful references for the reinforcement design for tunnel excavation adjacent to existing structures. [ABSTRACT FROM AUTHOR]

The complex distribution of synchronous grouting pressure results in excessive tunnel deformation and various structural diseases, especially for ultra-large-diameter shield tunnels. In this study, to reduce the risk of tunnel failure, a three-dimensional refined finite element model was established for the Wuhan Lianghu highway tunnel project, taking into account the non-uniform distribution of synchronous grouting pressure. This study focuses on investigating the development patterns of internal forces, deformations, and damages in segment structures under varying grouting pressure ratios. The results indicate that the primary failure mode of a segment is tensile failure occurring at the outer edge of the arch. Moreover, an increased ratio of grouting pressure between the arch bottom and top leads to a higher positive bending moment value and greater tensile damage at the arch waist. The tunnel ring gradually exhibits distinct "horizontal duck egg" shape deformation. When the grouting pressure ratio is 2.8, there is a risk of tensile cracking at the outer edge of the arch waist. At this time, the segment convergence deformation is 39.71 mm, and the overall floating amount reaches 43.12 mm. This research offers engineering reference for the prediction of internal forces and deformations in ultra-large-diameter shield tunnels during grouting construction, thereby facilitating their application in the development of resilient cities. [ABSTRACT FROM AUTHOR]

The introduction of fibres into soil can effectively improve its engineering properties. Systematically understanding the unsaturated mechanical properties of fibre-reinforced soil is highly significant. Moreover, there is currently no suitable model for describing the water-retention characteristics of unsaturated fibre-reinforced soil. The purpose of this study is to propose a model for the soil–water characteristic curve (SWCC) that can accurately describe unsaturated fibre-reinforced soil. The research focuses on unsaturated sand reinforced with PP fibres. A series of compression and direct shear tests were performed to investigate the mechanical behaviour. In addition, the SWCC was measured using the axis-translation technique. Based on the van Genuchten (VG) model, a modified model considering fibre reinforcement (VG-CFR) is developed for quantitatively analysing the influence of fibre content on the SWCC. The results showed that the established VG-CFR model can reflect the water-retention characteristics of fibre-reinforced sand. [ABSTRACT FROM AUTHOR]

The large underground structure in saturated stratum is vulnerable to float during an earthquake. This results in a plethora of problems, such as uneven settlement, large internal force and structure damage. In this study, the seismic behavior of a three-story, two-span subway station in complex saturated stratum was investigated through water-soil fully coupled 3D finite element method. In the analysis, the nonlinear soil behavior was described by a cyclic mobility model and the structure was calculated using a nonlinear constitutive model which can consider the influence of axial force on its bending moment. Joints elements were used to model the contact surface between soil and structure. The development of the soil displacement and internal force of the station structure at different times during a huge earthquake was examined. The bearing capacity of the station structure members was analyzed. The results indicated that the vertical displacement was spatially distributed. The larger additional seismic stresses appeared in the bottom slab and side wall. Failed elements were observed in both the walls and slabs, and the walls were more easily damaged than the slab. The results provide useful reference for the large underground structure seismic design in the construction of urban underground space. [ABSTRACT FROM AUTHOR]

The Shenzhen Ma Wan area has special geotechnical conditions, with more than 50% of the area being reclaimed rock formations. Riprap reclamation strata are particularly susceptible to significant deformation upon stress release. To comprehensively comprehend the reaction of existing pipelines to the excavation of an adjacent deep foundation pit within the riprap reclamation strata, an interaction of the soil–pipeline was conducted by encompassing both scaled model tests and numerical simulations based on a cross-sea channel project. Firstly, scaled model tests were performed on a soil–pipeline interaction caused by excavation. Subsequently, the numerical model was verified by comparing the numerical simulation results with the scaled model test results. Then, the internal force, strain of the pipeline, and soil surface deformation under the conditions of a soil layer with riprap were analyzed, and the results were compared with the case without riprap. Finally, the influence of the support structures was analyzed. The results indicated that the presence of the riprap in strata led to a 19% increase in vertical displacement of the ground surface and a 35% increase in the pipeline bending moment compared with the case without riprap in the same strata. The maximum internal force and strain occurred at an inclined angle of 45° in the pipeline section. Furthermore, it was found that the first lateral support after excavation played a pivotal role in controlling the overall deformation of the foundation pit. The changes in stiffness in the lateral support were more sensitive to the horizontal displacement than the vertical displacement of the pipeline. The results provide valuable insights for the design and safety evaluation of engineering projects in riprap reclamation strata. [ABSTRACT FROM AUTHOR]

This paper presents a case study of the clogging of a slurry-shield tunnel-boring machine (TBM) experienced during tunnel operations in clay-rich argillaceous siltstones under the Ganjiang River, China. The clogging experienced during tunneling was due to special geological conditions, which had a considerably negative impact on the slurry-shield TBM tunneling performance. In this case study, the effect of clogging on the slurry-shield TBM tunneling performance (e.g., advance speed, thrust, torque, and penetration per revolution) was fully investigated. The potential for clogging during tunnel operations in argillaceous siltstone was estimated using an existing empirical classification chart. Many improvement measures have been proposed to mitigate the clogging potential of two slurry-shield TBMs during tunneling, such as the use of an optimum cutting wheel, a replacement cutting tool, improvements to the circulation flushing system and slurry properties, mixed support integrating slurry, and compressed air to support the excavation face. The mechanisms and potential causes of clogging are explained in detail, and the contributions of these mitigation measures to tunneling performance are discussed. By investigating the actual operational parameters of the slurry-shield TBMs, these mitigation measures were proven to be effective in mitigating the clogging potential of slurry-shield TBMs. This case study provides valuable information for slurry-shield TBMs involving tunneling in clay-rich sedimentary rocks. [ABSTRACT FROM AUTHOR]

Adjacent construction around metro tunnels is a common situation in urban cities, which usually leads to the disturbance of surrounding soils and existing tunnels. Based on the influence zone theory, construction risks can be described in a graded manner. However, the calculation of the influence zone in existing research is mostly based on a single indicator, which is difficult to adapt to the increasingly stringent requirements of real projects. To address this limitation, a normalized method for the influence function and a weighted combination method for multi-indicators were proposed. These methods can combine any number of indicators to obtain an integrated result of the influence zone, facilitating direct guidance of engineering. Based on a case study of the Metro construction in Qingdao, a series of numerical simulations and calculations of the integrated influence zone was carried out. The results show that the shape of the integrated influence zone in this case is a necked bottle, i.e., the new tunnel causes a greater influence when it is below the existing tunnel. The change of soil layer and the weight of indicators both play important roles on the shape of the influence zone. The relevant conclusions and methods provide a basis for the safety assessment of similar projects. [ABSTRACT FROM AUTHOR]

Based on a cross-river tunnel of Wuhan Metro Line 8, we present a two-dimensional discrete element model for shield attitude adjustment considering the effect of overbreak cutters. The shield shell mechanics under the influence of over-excavation rate, over-excavation orientations, and overburden load are simulated, and the tunneling mechanics law and the ultimate range during the adjustment of the shield attitude are investigated. The simulation results indicate the following: (1) The greater the over-excavation rate, the smaller the force exerted by the soil layer in the negative direction of the shield movement; therefore, increasing the over-excavation rate is helpful in expanding the range of shield attitude adjustment. (2) The shield is stressed symmetrically while conducting positive and negative horizontal adjustments in the soil layer, which has a symmetrical distribution, but vertical upward adjustment is more difficult than vertical downward adjustment. (3) With the increase in overburden load, the space of the shield attitude adjustment is gradually reduced at the same over-excavation rate. A good engineering application was achieved in this project using the simulation model. It is recommended to use the attitude adjustment method by controlling the tunneling parameters. In difficult situations such as high overlying loads, the over-excavation cutter can be used to assist in adjusting the shield attitude. [ABSTRACT FROM AUTHOR]

The arrangement of multiple culverts has gradually increased in road engineering. However, the arrangement will face a series of risks in both the construction and operation stages. A numerical model was established to analyze the construction and operation safety of multiple steel corrugated pipe arch culverts by using a fully fluid–solid coupling two-dimensional (2D) model of a highway project. The sensitivity of factors affecting the settlement of the composite foundation such as modulus and depth of ground reinforcement was discussed. Based on the results of the 2D model, a fully fluid–solid coupling three-dimensional (3D) model was established to study the influence of dynamic cyclic vehicle load on the mechanical properties of multiple steel corrugated pipe arch culverts. The ground deformation, soil stress and pore pressure, structure stress, and deformation were analyzed. The results show that the maximum settlement of the soil in the arch culvert area is at the junction of the two different arch culverts after construction. The maximum vertical deformation of the structure appears at the vault, and the arch waist is prone to stress concentration. Under cyclic vehicle dynamic load, the ground deformation, structural stress, and arch culvert subgrade deformation showed a rapid growth stage, and then tended to be stable. The weak points in the structure during the construction and operation stages were revealed, which can provide a useful reference for the design and construction of multiple steel corrugated pipe arch culverts. [ABSTRACT FROM AUTHOR]

The slurry infiltration process contributes significantly to the stability of tunnelling face during the application of slurry pressure balanced tunnel boring machine (SPB TBM) in construction. A coupled computational fluid dynamics and discrete element method (CFD-DEM) model is developed to simulate the formation and long-term impermeable stability of filter cake considering different infiltration conditions, e.g., the cohesiveness of bentonite slurry and the permeability of sandy ground. The morphology of formed filter cakes and the pressure drops are analysed macroscopically. Then, the long-term impermeable stability of filter cakes under increasing slurry pressure is evaluated based on the evolution of the pressure gradient magnitude along the infiltration direction; additionally, the contact and force fabrics of filter cakes are examined to investigate their failure process from the micro-mechanical aspect. The numerical results indicate that the increase of size ratio of sand to slurry particle and the slurry cohesion restrain and enhance, respectively, the formation of filter cakes and their long-term permeable and mechanical stability subjected to dynamic hydraulic loads. This work contributes to the further development of the phenomenological model and the micromechanical constitutive model of slurry infiltration involving multifield and multiphase media. [ABSTRACT FROM AUTHOR]

Experimental results provide strong evidence that the deformation and strength of rocks are closely related to the damage suffered during loading. The classic constitutive models such as Mohr–Coulomb criterion and the Drucker–Prager criterion are usually unable to describe the non-linear deformation behavior of rocks, including strain hardening and softening. Their applications in numerical analysis and practical engineering are limited. For this purpose, an elastoplastic damage constitutive model that takes into account the competition mechanism between damage and strain hardening or softening during rock compression is proposed herein. This model is used to investigate the deformation behaviors and damage evolution of rocks. More importantly, this model has been implemented by finite element programming code and verified by a series of triaxial compression tests. The comparison results between theoretical analysis and experimental data indicate that this model can well describe the stress–strain curves and damage–strain curves of the investigated rocks (sandstone and salt rock), especially the characteristics of softening, hardening and residual strength. Based on parametric analysis, the influence of confining pressure, scale parameter and shape parameter on rock damage is revealed. It is found that the rock scale parameter in this model has a power function relationship with confining pressure. The ultimate plastic deformation that rocks can withstand is related to the scale parameter. The shape parameter controls the residual strength and deformation of rocks. Model results demonstrate that the strength and deformation vary with rock properties, and are strongly dependent on the stress-induced damage and strain characteristics. [ABSTRACT FROM AUTHOR]

Urban development is promoting aboveground-underground city integration. Underground engineering and surrounding buildings and infrastructure form an underground engineering environment (UEE). In critical disasters, damage to the UEE not only causes chain damage to the surroundings but also aggravates urban resilience. Few studies have focused on UEE resilience and its disaster reduction. This study investigated the emergency restorability of the UEE to fill this research gap. First, we classified the restoration levels based on UEE damage patterns. Second, we performed subregion optimization based on cast-in-situ (CIS) restoration, and technical optimization by utilizing prefabrication and assembly technology (PAT). Third, the CIS/PAT UEE emergency restorability functions were constructed based on these optimizations and the local assembly capacity. Finally, the performance of the CIS/PAT restoration, optimization effect, and local assembly capacity were analyzed using a case study. The results indicated that (1) meticulous subregion optimization significantly reduced environmental work with a 13.5% speed up; (2) technical optimization incorporating PAT had the highest efficiency for improving UEE emergency restorability; (3) PAT restoration enhanced the structural resilience and functional resilience of the UEE by at least 28.34% and 62.27% over CIS restoration, respectively; (4) upper and lower thresholds exist for assembly speed in PAT restoration; (5) there exist three types of assembly capacity in PAT restoration: ring-quantity-sensitive, ring-weight-sensitive, and insensitive; and (6) the adaptive schemes maximized the performance of different local assembly capacities in PAT restoration. The UEE emergency restorability function provides a quantitative assessment tool for the resilience of UEE and a resilience enhancement scheme for disaster reduction. [ABSTRACT FROM AUTHOR]