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In the past, several experimental and theoretical studies have been carried out to evaluate the ultimate bearing capacity (UBC) of geosynthetic-reinforced sandy soil foundations (GRSSFs). The experimental studies consist of model footing load tests which are expensive and time consuming whereas the results obtained by theoretical expressions often lack consistency. In the study reported in this paper, a cost-effective, extreme learning machine (ELM) model was used for the first time to obtain a more realistic prediction of the UBC of a GRSSF. A large dataset consisting of actual field and laboratory measurements of UBC was used to develop and validate the model. Its predictive performance was then compared against robust machine learning regression models and traditional theoretical methods. The study shows that the proposed model is useful and attains an adequate level of accuracy in predicting the UBC of GRSSFs when compared with other data-driven models and some traditional methods. The research also shows that the ELM technique is a realistic and reliable approach that could be employed in geotechnical engineering intelligent systems for the prediction of multivariate non-linear problems.

The long-term settlement of calcareous sand foundations caused by daily periodic fluctuations has become a significant geological hazard, but effective monitoring tools to capture the deformation profiles are still rarely reported. In this study, a laboratory model test and an in situ monitoring test were conducted. An optical frequency domain reflectometer (OFDR) with high spatial resolution (1 mm) and high accuracy (±1 μe) was used to record the soil strain responses to groundwater table and varied loads. The results indicated that the fiber-optic measurements can accurately locate the swelling and compressive zones. During the loading process, the interlock between calcareous sand particles was detected, which increased the internal friction angle of soil. The foundation deformation above the sliding surface was dominated by compression, and the soil was continuously compressed beneath the sliding surface. After 26-48 h, calcareous sand swelling occurred gradually above the water table, which was primarily dependent on capillary water. The swelling of the soil beneath the groundwater table was completed rapidly within less than 2 h. When the groundwater table and load remain constant, the compression creep behavior can be described by the Yasong-Wang model with R2 = 0.993. The daily periodically varying in situ deformation of calcareous sand primarily occurs between the highest and lowest groundwater tables, i.e. 4.2–6.2 m deep. The tuff interlayers with poor water absorption capacity do not swell or compress, but they produce compressive strain under the influence of deformed calcareous sand layers.

Biochar has recently been gaining increasing attention as a stable and sustainable soil amendment material. However, the effect of biochar amendment on the desiccation behaviour of coastal soils has not yet been examined. Consequently, the present study primarily investigated the effect of exposing biochar-amended marine soil (BAS) to constant and cyclic temperatures on its swell–shrink, evaporation and desiccation cracking characteristics. Biochar contents of 1%, 2%, 4% and particle size ranges of PS-1 (600 μm D ≤ 2000 μm), PS-2 (300 μm D ≤ 600 μm), PS-3 (D ≤ 75 μm) (D: biochar particle diameter) were employed. It was revealed that the absolute volumetric shrinkage of both unamended and biochar-amended specimens increased as the number of thermal cycles increased. Under continuous heat exposure, 4% (PS-3) BAS in compacted state achieved the maximum reduction in volumetric shrinkage which was 42%. Moreover, under continuous heat exposure, 2% (PS-1) BAS in slurry state achieved the highest reduction in desiccation cracking, which was 73%. The present study highlights the importance of identifying the most effective combination of biochar content and particle size required to achieve a desired outcome, in order to gain the maximum benefit of biochar as an amendment material at the lowest possible cost.

There is a varying prevalence of olfactory and taste dysfunction (OTD) in COVID-19 patients, with a higher prevalence reported in the European population as compared to the Asian population. Psychophysical tests are crucial to determine the exact frequency, extent and clinical characteristics of these OTDs. The present study objectively evaluated the OTD for patients treated in the Dedicated COVID-19 Hospital (DCH) in Shahdol. This prospective cross-sectional study was conducted after IEC approval in DCH Shahdol for a period of four months among RT-PCR positive patients, and they were evaluated using validated chemosensitive psychophysical test during ENT consultation to identify OTD. The sample size was calculated as 92 considering prevalence (p) of OTD as 41.3% by applying formula: n = (Z1-a/2)2 × p (1-p) / d 2. The information pertaining to the subjects was kept anonymous and confidential. During data analysis, an association was significant for p value < 0.05. It was observed that 45.5% of subjects reported either loss of taste or smell. During objective evaluation, olfactory and taste dysfunction was observed among 42.4% of subjects (95/224). The Chi-square analysis reflected statistically significant difference (p < 0.05) between subjects with OTD and without OTD for the variables such as days from onset of symptoms to admission, and symptoms (fever, sore throat and shortness of breath). Taste and smell are among the important senses and in India they are mostly subjectively evaluated for COVID-19 induced OTD which results in underreporting of these symptoms. So, a gold standard objective evaluation should be taken into consideration to evaluate OTD.

In order to ensure safe and sustainable design of geosynthetic-reinforced soil foundation (GRSF), settlement prediction is a challenging task for practising civil/geotechnical engineers. In this paper, a new hybrid technique for predicting the settlement of GRSF has been proposed based on the combination of evolutionary algorithm, that is, grey-wolf optimisation (GWO) and artificial neural network (ANN), abbreviated as ANN-GWO model. For this purpose, the reliable pertinent data were generated through numerical simulations conducted on validated large-scale 3-D finite element model. The predictive power of the model was assessed using various well-established statistical indices, and also validated against several independent scientific studies as reported in literature. Furthermore, the sensitivity analysis was conducted to examine the robustness and reliability of the model. The results as obtained have indicated that the developed hybrid ANN-GWO model can estimate the maximum settlement of GRSF under service loads in a reliable and intelligent way, and thus, can be deployed as a predictive tool for the preliminary design of GRSF. Finally, the model was translated into functional relationship which can be executed without the need of any expensive computer-based program.

In this study, a multivariate adaptive regression splines (MARS) model has been developed to predict the settlement of shallow reinforced sandy soil foundations (RSSFs). The potential of the MARS model is validated comparatively with four other robust artificial intelligence/machine learning regression models, namely extreme learning machines (ELM), support vector regression (SVR), Gaussian process regression (GPR), and stochastic gradient boosting trees (SGBT). The pertinent data retrieved from previously published well-established scientific studies have been used to calibrate and validate the data-driven intelligent machine learning models. The predictive strength of all the modelling tools mentioned above were assessed via several statistical indices. Moreover, the predictive ability and reliability of the developed models were also corroborated with ranking criteria and external validation analysis. The results as obtained have shown that the MARS modelling technique attains the superior veracity in predicting the settlement of reinforced foundations.

In the recent past, the potential benefits of wraparound geosynthetic reinforcement technique for constructing the reinforced soil foundations have been reported. This paper presents the experimental study on the behaviour of model strip footing resting on sandy soil bed reinforced with geosynthetic in wraparound and planar forms under monotonic and repeated loadings. The geosynthetic layers were laid according to the reinforcement ratio to minimise the scale effect. It is found that for the same amount of reinforcement material, the wraparound reinforced model resulted in less settlement in comparison to planar reinforced models. The efficiency of wraparound reinforced model increased with the increase in load amplitude and the rate of total cumulative settlement substantially decreased with the increase in number of load cycles. The wraparound reinforced model has shown about 45% lower average total settlement in comparison to unreinforced model, while the double-layer reinforced model has about 41% lower average total settlement at the cost of approximately twice the material and 1.5 times the occupied land width ratio. Moreover, wraparound models have shown much greater stability in comparison to their counterpart models when subjected to incremental repeated loading.

Marston’s load theory is commonly used for understanding the soil–conduit interaction. However, there are no practical methods available which can estimate the Marston’s soil prism (MSP) width ratio. Moreover, the advent of soft computing methods has made many traditional approaches antiquated. The main purpose of this work is to compare and evaluate the predictive abilities of several machine learning-based models in predicting the MSP width ratio for the reinforced concrete (RC) and corrugated steel (CS) conduits. By utilizing the finite element modelling, a large-scale dataset was generated for the width of the soil prism for both types of conduit material, when buried under sandy soils of varying stiffness. After preparing the required dataset, feature validity technique based on correlation-based feature selection was employed to find the most influential parameters affecting the MSP width. Thereafter, five regression-based data driven models namely artificial neural networks (ANN), least-square support vector regression, extreme learning machine, Gaussian process regression, and multiple linear regression were developed to forecast the MSP width ratio. The results showed that the ANN outperforms the other predictive models for both the conduit types. In addition, due to the excellent overall performance of the ANN, it was translated into functional relationship for predicting the MSP width ratio for RC and CS conduits.

In the present paper, the seismic response of cohesive-frictional soil slope has been investigated in the time-domain by using the 1995 Kobe earthquake records. A 2-dimensional dynamic finite element model has been developed in the plain-strain condition by considering the elastic perfectly plastic Mohr-Coulomb soil model criterion. The analysis simulates maximum horizontal and vertical seismic accelerations simultaneously at the base of the slope. The seismic response of the slope under combined seismic accelerations has been reported in terms of the displacement induced during the earthquake shaking period. The results show that the induced displacement of slope under combined seismic loadings is greater compared to the case of horizontal loading only. Further, the slope is expected to fail at the toe level first rather than at the crest level.

This paper presents experimental and numerical investigations of dense sand slopes supporting an embedded strip footing, considering both unreinforced and geotextile-reinforced cases. The effect of footing location, defined in terms of embedment depth D and edge distance e, on the bearing capacity of the footing was investigated. The results show that the bearing capacity of the footing increased with an increase in D and e. The inclusion of one layer of geotextile reinforcement in the dense sand slope further increased the bearing capacity. This benefit was expressed in terms of BCRu, which is defined as the ratio of the ultimate bearing capacity for the reinforced case to the ultimate bearing capacity for the unreinforced case. The maximum value of BCRu( ≈ 2·5 − 3) was observed for D/B = 0 and e/B = 0 where B is the width of the footing, while the minimum value of BCRu( ≈ 1·5) was obtained for D/B = 1 and e/B = 3.

This paper addresses the issue of the latest analytical method when tackling a vacuum consolidation problem in a ground improvement project using prefabricated vertical drains (PVD) and the necessity of using numerical simulation. This paper aims to introduce a matching scheme to derive appropriate soil and drain properties in analytical solution and numerical modeling (axisymmetric and plane strain conditions). The scheme started with the analytical solution with a trial process of matching the predicted and measured settlements. The derived parameters are then adopted in the numerical modeling. Depending on the scenarios considered including axisymmetric and plane strain conditions, some parameters such as permeability need to be adjusted to have the best fit in the settlement estimation. In situ monitoring data from a case history of a road construction project in Vietnam was adopted in the back-analysis to demonstrate the application of the proposed matching scheme. In addition, the effectiveness of soft ground treatment by prefabricated vertical drain is evaluated in numerical modeling and field measurement. Very good agreement in settlement behavior and the effective stress variation between numerical simulation and field measurement have illustrated the proposed matching scheme’s appropriateness.

In the recent times, the use of geosynthetic-reinforced soil (GRS) technology has become popular for constructing safe and sustainable pavement structures. The strength of the subgrade soil is rout...

Visual-analytics-guided systems are replacing human efforts today. In many applications, movement in off-road terrain is required. Considering the need to negotiate various soft ground and desertic conditions, the beaten tracks of leading vehicles considered to be safe and suitable for guiding are used in such operations. During night, often, these tracks pass through low-contrast conditions posing difficulty in their identification. The maximization of track contrast is therefore desired. Many contrast enhancement techniques exist but their effectiveness varies as per the surrounding. Other than conventional techniques, the role of texture too becomes important for enhancing the differentiable track contrast. Gray-level co-occurrence matrix (GLCM)-based statistic measures are used here to evaluate the track texture. These measures are seen to improve the contrast of vehicle tracks significantly. A track-index-based technique is proposed to sort various images as per their effectiveness in increasing the track contrast. Different forms of track indices are proposed and compared. The proposed track index is seen as effective in sorting 88.8% of contrast images correctly. The proposed technique of creating and sorting images based on the contrast level is seen as a useful tool for improved fidelity in many difficult situations for making the off-road operations sustainable.

The wraparound reinforcement technique has been studied recently by researchers as a way of improving the bearing capacity and load−settlement characteristics of a sand bed supporting a strip footing with a constant land width for foundation, but with the use of varying width of geotextile reinforcement. This research study presents an experimental evaluation of geotextile-reinforced sand bed enhanced with a wraparound reinforcement technique having partially and fully wrapped ends with the use of constant width of the geotextile reinforcement, but with varying land width of the foundation. Laboratory model tests were conducted to investigate the influence of the lap length coverage of wraparound ends on the load−settlement behaviour of reinforced sand. Additionally, an instrumentation programme with pressure cells was designed to study the pressure distribution in foundation sand beneath the geotextile layer. The test results reveal that fully wrapped models possess the most improved behaviour, with about 50% improvement in the bearing capacity and 50% reduction in the land width occupied by the reinforcement compared with a reinforced model without wraparound ends.

In the recent past, the wraparound geosynthetic reinforcement technique has been recommended for constructing the geosynthetic-reinforced soil foundations. This paper presents the development of an analytical expression for estimating the ultimate bearing capacity of strip footing resting on soil bed reinforced with geosynthetic reinforcement having the wraparound ends. The wraparound ends of the geosynthetic reinforcement are considered to provide the shearing resistance at the soil-geosynthetic interface as well as the passive resistance due to confinement of soil by the geosynthetic reinforcement. The values of ultimate load-bearing capacity determined by using the developed analytical expression agree well with the model footing load test values as reported in the literature.

A realistic estimation of load distribution over the buried structures is necessary for proper analysis of pipes/conduit, culverts and tunnel lining. Pipelines are often constructed in the areas of civil engineering, mining engineering, agriculture and some other areas. For the design of pipeline, it is essential to know the load over it. Load distribution over the buried structures has been investigated scientifically during the past several decades. The method of investigation includes experimental, analytical and numerical methods. The finite-element models based on some commercial software have been developed for load analyses for design of the pipeline and buried structures. The geosynthetic is an effective reinforcement layer to reduce the load over the buried structure. Although some small-scale studies have indicated that the geosynthetic layer can reduce the load over the buried structure, the investigation on a large scale is limited. Therefore, in this paper, an attempt is made to investigate the load-distribution behaviour of geosynthetic layer as a reinforcement within the soil cover over the HDPE and PVC pipes. The study has been carried out by developing a numerical model of the problem using the commercial software PLAXIS 3D. The comparison of HDPE and PVC pips shows that the pressure around the PVC pipe is greater than the pressure around HDPE pipe, while pressure around the larger diameter HDPE pipe is lower than the pressure around the smaller diameter HDPE pipe. The pressure on the crown of the pipe decreases with presence of the geosynthetic reinforcement layer; the optimal distance between geosynthetic reinforcement layer and pipe is equal to the pipe diameter. The pressure reductions on the crown of the HDPE and PVC pipes, having a diameter of 914 mm, are 31% and 27%, respectively. The graphical presentations may be used as the design charts for designing the buried pipes.

A fuzzy logic (FL)–based modeling approach is employed for geogrid-reinforced subgrade soil of unpaved roads. A review of the literature reveals that fuzzy logic has not been used for predicting the behavior of geogrid-reinforced subgrade. This paper presents FL-based two models with fuzzy Triangular and Gaussian membership functions for input and output variables. It consists of eight input parameters/factors, namely, reinforced/unreinforced section, depth of reinforcement, liquid limit, plastic limit, plasticity index, optimum moisture content, maximum dry unit weight, and soaked/unsoaked condition, and California bearing ratio (CBR) as an output parameter. The fuzzy rules are deduced from the experimental data. The laboratory CBR tests were performed on the subgrade soil reinforced with geogrid. The precision of models was examined by comparing the predicted CBR values with the experimental CBR values for Triangular and Gaussian membership functions. The sensitivity analysis reflects a set of dominant parameters. The results indicated a significant improvement in the CBR value of geogrid-reinforced subgrade soil due to the inclusion of geogrid. The range for optimal depth of geogrid reinforcement is found to be 36 to 60% of the thickness of the soil layer. The potentialities of FL were found to be satisfactory.

Pavement structures constructed on the expansive soil subgrade experience a higher upward pressure compared to any other subgrade material. The upward pressure is caused due to high swelling and shrinkage characteristics of expansive clay soil. The present study has investigated and identified the mechanisms by which a remolded expansive soil can be modified to reduce the upward pressure and swelling (heave). To achieve this, a lightweight, environmentally friendly, and high pressure resistive expanded polystyrene (EPS) granules have been used with expansive soil s from three different locations of Madhya Pradesh state, India. The study has been performed to understand the swelling and strength characteristics of soil with and without the use of EPS (density = 21.6 kg/m3) as per ASTM specifications. The chemical and microstructural components of the expansive soil were investigated using autotuned total reflectance Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). Several laboratory experiments, including optimum moisture content, maximum dry unit weight, grain-size distribution, liquid limit, plastic limit, shrinkage limit, free swell index, unconfined compressive strength, and pressure swelling tests were carried out on the statically compacted expansive clay soil specimen with and without EPS (0.25%, 0.50%, 1.00%). The maximum addition of EPS was considered as 1% as the very high expansion was observed, and beyond this, further addition of EPS was not feasible. The results show that the swelling pressure, expansion percentage, and time rate of swell decrease, whereas the unconfined compressive strength (UCS) increases with the addition of EPS. The inclusion of EPS in expansive clay soil exponentially reduced the heave and the upward pressure, whereas the maximum UCS was observed at 0.5%.

In the present work, seismic performance parameters have been reviewed by considering the possible combined action of vertical and horizontal seismic loadings of the ground motion during the earthq...

Geotextile and geogrid are used routinely to reinforce the unpaved roads to enhance the serviceability and stability of these roads. Field performance studies were conducted on unpaved test sections reinforced with geotextile and geogrid to demonstrate how geosynthetics improve the test section performance using dynamic cone penetrometer (DCP). The influence of geosynthetic reinforcement was investigated by placing the reinforcement layer at subgrade-base interface, thus helps to achieve more sustainable unpaved test section. Direct shear tests were conducted on soil samples reinforced with geotextile and geogrid to investigate the improvement in shear strength of geosynthetic reinforced soil. The results of DCP test were demonstrated as dynamic cone penetration index value (DCPI, mm/blow). DCPI values were observed in range from 1 to 7 mm/blow, corresponding to 500 mm depth of penetration for unreinforced and geogrid-reinforced test section and 312 mm depth of penetration for geotextile-reinforced test section respectively. A decrease in DCPI value was observed for the geosynthetic-reinforced unpaved test section as compared to the unreinforced unpaved test section. Direct shear test results shows a significant improvement in the shear strength of soil samples reinforced with geotextile.