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Calcareous sand has been widely used as a construction material for offshore projects; however, the problem of foundation settlement caused by particle crushing cannot be ignored. Although many methods for reinforcing calcareous sands have been proposed, they are difficult to apply on-site. In this study, a permeable polyurethane polymer adhesive (PPA) was used to reinforce calcareous sands, and its mechanical properties after reinforcement were investigated through compression creep, direct shear, and triaxial shear tests. The reinforcement mechanism was analyzed using optical microscopy, CT tomography, and mercury intrusion porosimetry. The experimental results indicate that there is a critical time during the compression creep process. Once the critical time is surpassed, creep accelerates again, causing failure of the traditional Burgers and Murayama models. The direct shear strength of the fiber- and geogrid-reinforced calcareous sand reinforced by PPA was approximately nine times greater than that without PPA. The influence of normal stress was not significant when the moisture content was less than 10%, but when the moisture content was more than 10%, the shear strength increased with an increase in vertical normal stress. Strain-softening features can be observed in triaxial shear tests under conditions of low confining pressure, and the relationship between the deviatoric stress and strain can be described using the Duncan–Chang model before softening occurs. The moisture content also has a significant influence on the peak strength and cohesive force but has little influence on the internal friction angle and Poisson's ratio. This influence is caused by the different PPA structures among the particles. The higher the moisture content, the greater the number of pores left after grouting PPA. [ABSTRACT FROM AUTHOR]

The sustainable development of marine environments requires a deep understanding of their chemical and biological conditions. These are significantly impacted by the exchange of substances such as contaminants, heavy metals, and nutrients between marine sediments and the water column. Although the existing literature has addressed the physics of enhanced solute migration in sediment due to sea waves, the role of coupled flow and soil deformation has often been neglected. This study investigates the effects of wave-induced soil deformation on solute release from the marine sediment using a coupled numerical model that incorporates the effect of soil deformation into the advection–diffusion equation. The results reveal that solute release is notably accelerated in deformable sediments with a smaller shear modulus, with the longitudinal dispersion coefficient increasing up to five times as the shear modulus decreases from 108 Pa to 106 Pa. This enhancement is more pronounced in shallow sediments as the sediment permeability decreases, where the longitudinal dispersion coefficient in deformable sediments can be 15 times higher than that in non-deformable sediments at a hydraulic conductivity of 1 × 10−5 m/s. Furthermore, the rate of solute release increases with decreasing sediment saturation due to the compressibility of pore water, although this rate of increase gradually diminishes. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The h-type pile (hTP pile) is a complex anti-slip pile system, which connects the front pile and the back pile through beams. When it is used in engineering, there is a complex soil arch effect between the soil and the hTP piles, which makes the complex anti-slip mechanism. In this paper, the discrete element method is used to establish the hTP pile models, analyze the displacement and stress distribution law of the soil body and investigate the spatial distribution and variation patterns of soil arches, this can provide a basis for the design of hTP. The results indicate that the soil arch structure formed under the displacement between hTPs can be divided into four stages: initial stage, development stage, overlapping stage and stable stage. The development speed of the soil arch between the rear piles is slower than that of the soil arch between the former piles. As the depth of the soil increases, the arch line of the soil arch gets closer to the rear pile. The soil arch of the stress between hTPs can be divided into initial stage, development stage and stable stage. The time step corresponding to the stable stage of the stress in the horizontal direction is equal to the sum of the horizontal displacement generated by the overlapping stage and the stabilization stage. The stress of the soil slope gradually decreases and extends from the surface to the bottom layer of the slope. Soil arches appear on the rear side of both the front and rear piles at different anti-slip pile spacings, and they all tend to overlap. The increase in pile spacing does not have a significant effect on the ratio of soil arch height and soil arch span, and the evolution of soil arch is similar between hTP at different pile spacings. All above can provide reference for the application and design of hTPs. [ABSTRACT FROM AUTHOR]

Predicting soil deformation is critical for the success of building construction projects. The traditional methods used for this task, which rely on theoretical calculations and numerical simulations, require detailed information on soil characteristics and geological conditions. These essential details are often challenging to obtain in practical engineering, thereby limiting the accuracy of these methods in building construction contexts. Deep learning (DL) provides a direct approach for modeling soil deformation without having a detailed understanding of the soil properties and geological conditions. However, the existing DL algorithms mainly focus on modeling deformation directly. With advancements in monitoring technology, integrating diverse monitoring data has become crucial for accurately predicting deformation, a need often overlooked in current practices. This paper introduces a monitoring data fusion (MDF) model aimed at enhancing the utilization efficiency of diverse monitoring data. Validated against real-world engineering scenarios, this model significantly outperforms traditional single-feature and multi-feature long short-term memory (LSTM) models. It achieves a mean absolute percentage error (MAPE) of approximately 2.12%, representing reductions of 30% and 63%, and a root mean square error (RMSE) of around 12.5 mm, with reductions of 36% and 77%. Additionally, the DL interpretability method, Shapley additive explanations (SHAP), is utilized to elucidate how various model features contribute to generating predictions. [ABSTRACT FROM AUTHOR]

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In projects such as highway bridges and offshore wind farms, understanding the kinematics of soil layers and their displacement is important for accurately predicting the behavior of caissons and monopiles under lateral loads. To better predict the distribution of soil deformation around the foundations, this paper presents an extensive usage of the energy-based variational method in laterally loaded deep foundations (caissons or monopiles) with very large diameters. By adding an assumption of soil deformation in multilayered soils, the displacement distribution around the foundations can be better described. The responses of deep foundations were obtained by minimizing the potential energy and virtual work of the foundation-soil system. After that, static lateral loading tests on two caissons with the same embedment depth of 36 m and the same diameter of 6 m were performed, and the displacement field in soils and the deflection profiles of the caissons were measured. Results show that the lateral displacement and the decay distribution fields calculated from the theory in this paper agree with the measured data from the static loading tests and the corresponding finite differential method (FDM) results. At last, a series of case studies performed by MATLAB and FDM analyses were also conducted to study the influence of uz on the response of foundations, as well as the influence of foundation parameters and soil modulus on the value of ϕz. [ABSTRACT FROM AUTHOR]

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In this study, we instrument the foundations and towers for two onshore shallow wind turbine generators (WTGs) to evaluate foundation response, quantify in-service loads, and assess the assumptions behind WTG foundation design calculations. Measurements of pressure at the soil–foundation interface, soil strain just below foundation level, and tower moments over long periods provide insights into the operational moments experienced by the tower and the load transfer mechanisms to the foundation system. The results of this study have implications for design practices in three distinct ways: (1) the assessment of rotational stiffness calculation assumptions, (2) the evaluation of pressure distribution used in the bearing capacity formulation, and (3) the estimation of tower loads used in the tower and anchor bolt design. Our observations show that the induced overturning moments correlate well with incipient wind speeds and directions and the associated soil pressure and strain responses. The overturning moments and the response parameters relate linearly within the spectrum of measured magnitudes. However, the pressure distribution across the foundation footprint does not monotonically increase or decrease with distance from the neutral axis of the foundation base (e.g., the pressure sensed at the foundation's center close to the foundation is between 1.5 and 2 times greater than the pressures sensed at the edges). In addition, the measured soil strain as a function of cyclic moments shows that the in-service cyclic shear strains are less than 1.4 × 10−5 (i.e., two orders of magnitude smaller than the assumed design strain level). Finally, the spectrum of cyclic moments follows a semilog trend, thus indicating that operational and nonoperational loads dominate the fatigue load spectrum. Our study suggests that adequately designed WTG foundations on competent fine-grained soil result in very low operational soil shear stresses and strains, which might indicate that the current design practices are too conservative in nature. Field measurements establish load spectrums for cyclic fatigue loads for the long-term operational conditions of WTGs. [ABSTRACT FROM AUTHOR]

Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Calcareous sand has been widely used as a construction material for offshore projects; however, the problem of foundation settlement caused by particle crushing cannot be ignored. Although many methods for reinforcing calcareous sands have been proposed, they are difficult to apply on-site. In this study, a permeable polyurethane polymer adhesive (PPA) was used to reinforce calcareous sands, and its mechanical properties after reinforcement were investigated through compression creep, direct shear, and triaxial shear tests. The reinforcement mechanism was analyzed using optical microscopy, CT tomography, and mercury intrusion porosimetry. The experimental results indicate that there is a critical time during the compression creep process. Once the critical time is surpassed, creep accelerates again, causing failure of the traditional Burgers and Murayama models. The direct shear strength of the fiber- and geogrid-reinforced calcareous sand reinforced by PPA was approximately nine times greater than that without PPA. The influence of normal stress was not significant when the moisture content was less than 10%, but when the moisture content was more than 10%, the shear strength increased with an increase in vertical normal stress. Strain-softening features can be observed in triaxial shear tests under conditions of low confining pressure, and the relationship between the deviatoric stress and strain can be described using the Duncan–Chang model before softening occurs. The moisture content also has a significant influence on the peak strength and cohesive force but has little influence on the internal friction angle and Poisson’s ratio. This influence is caused by the different PPA structures among the particles. The higher the moisture content, the greater the number of pores left after grouting PPA.

Featured Application: This work proves the feasibility and effectiveness of upcutting belt motion to reduce the draught resistance of subsoilers, which is also a reference and experience for the optimization and modification of other soil-engaging components. Conventional subsoiling has the problem of excessive draught resistance, which has long been a major concern. A great reduction in draught is urgently required to make better use of the subsoiling technique with many agronomic benefits. In this study, an attempt was made to test the draught reduction performance of a series of tools with continuous belt motions. Comparative simulations between regular tools and belt tools were carried out using the discrete element method (DEM) to investigate the effects of belt motion on tool force, soil disturbance characteristics, particle velocity distribution, and soil deformation and movement patterns. The results indicated that the belt motion reduced the draught force by 13.18%, 25.21%, 37.98%, and 44.64% for the rake angles of 30°, 45°, 60°, and 75°, respectively, and caused acceptable increases in downward vertical force. The changes in soil disturbance, particle velocity distribution, and soil deformation and movement patterns contributed to the reduction in draught force. Negative effects on soil disturbance were acceptable considering the 13.18% to 44.64% reductions in draught force. The present study suggests that the belt motion has a great application potential for draught reduction in subsoiling. Also, this can serve as a theoretical foundation for future studies. [ABSTRACT FROM AUTHOR]

In order to study the influence of temperature change on the strength and deformation of silty clay in natural state and saturated state, the silty clay widely distributed in typical seasonal frozen area was taken as the research object. The triaxial test of unsaturated soil in natural state and saturated silty clay under different temperature conditions was carried out by global digital system (GDS) unsaturated soil triaxial test system and GDS temperature-controlled static / dynamic triaxial test system. The experimental results show that the stress-strain curves of unsaturated and saturated silty clay show the characteristics of strain hardening. The cohesion of unsaturated silty clay increases with the decrease of temperature, while the internal friction angle decreases with the decrease of temperature, but the overall change trend is small. The cohesive force of saturated soil is the same as that of unsaturated soil. With the decrease of temperature, the cohesive force increases gradually, but the cohesive force is smaller than that of unsaturated soil at the same temperature, and the internal friction angle decreases first and then increases. When there is no vertical pressure, the axial deformation of unsaturated and saturated silty clay increases with the decrease of temperature under the same confining pressure, and the axial deformation of both decreases with the increase of confining pressure under the same temperature. The test results can provide theoretical basis for the design and construction of silty clay stratum engineering in seasonal frozen area. [ABSTRACT FROM AUTHOR]

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Taking mechanical property differences of rock and soil layers into consideration, a method of calculating ground settlement caused by tunnel excavation in composite strata by means of uniting complex variable function and stochastic medium theory is proposed. Firstly, via complex variable function the analytical solution of rock strata under the conditions of self-weight of upper soil layer and non-uniform deformation of tunnel can be obtained, and the settlement deformation of rock-soil interface is gotten, and regard the area surrounded by the interface as “unequal thickness excavation”. Then, with the use of stochastic medium theory, surface settlement value is calculated. By summing up two examples of tunnel excavation in composite strata and analyzing the differences between calculated results and measured values, it can be noted that the agreement between calculated results and measured values of geotechnical stratification method is obviously better than the calculation method considering rock and soil layers as medium. In addition, it is concluded that the tunnel convergent deformation influences strata deformation more and surface less by considering the influence of different tunnel convergent deformation modes, soft-hard ratio of overlying strata and influence angles of soft soil on strata deformation. The soft-hard ratio of overlying strata has a great influence on strata deformation and influence zone. The larger the influence angle of soil layer is, the larger surface deformation will go, and the influence zone of ground surface will reduce with it. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Suction caissons are widely used for anchoring floating platform and offshore wind turbines. Penetration of the suction caisson into the desired position under the combination of its self-weight and applied suction resulted from pumping out the encased water is integral to practical engineering. Model tests were carried out to investigate the suction-assisted installation of suction caissons in clay under various undrained shear strengths. It was found that there exists a critical penetration depth value. When the penetration depth is smaller than the critical value, the soil plug undrained shear strength is higher than intact clay (i.e., clay prior to installation). However, when the penetration depth is greater than the critical penetration depth, the undrained shear strength of soil plug is lower than intact clay. The critical value decreases with the increasing consolidation time and undrained shear strength of clay. During suction-assisted installation, cracks occur around suction caissons. The installation way has little effect on the crack formation. The influence range (i.e., the maximum distance between the crack and the suction caisson edge) was found to increase with the increasing friction coefficient of interface between the suction caisson wall and soil and decreases with the increasing soil undrained shear strength. In addition, the drained condition of the clay during installation is dominated by the caisson aspect ratio, the undrained shear strength and the friction coefficient between the caisson wall and clay. Equations to estimate the penetration resistance and the required suction to install the suction caisson are summarized. [ABSTRACT FROM AUTHOR]

For effective tillage, design and selection of tillage tool according to soil type and condition is very important. The present study is carried out for in-depth investigation of different types of shovels of tine cultivator and behavior of soil in response to loads subjected during tillage using finite element analysis. Different types of shovels like reversible, duck foot, seed drill and cultivator shovel are simulated with different types of soil like sand, clay and loam. The origination, level and distribution of stresses and deformations in shovels experienced in different types of soils are probed. Furthermore, high stressed and crack sensitive regions are identified. The stresses of 18, 53, 64 MPa are generated in reversible shovel of tine cultivator during ploughing in sandy, clay and loamy soil respectively. In addition, results of different shovels are compared, and it is found that the duck foot type shovel experiences highest stress and deformation. The duck foot shovel experiences about 20 and 71% higher stresses in loam compared to that in clay and sand respectively. Moreover, the study of soil mechanical behavior shows that the soil block (clay soil) experiences maximum stress of 34 MPa while tilling with reversible shovel. The statistical analysis is also conducted that shows high significance of simulation results.

Predicting soil deformation is critical for the success of building construction projects. The traditional methods used for this task, which rely on theoretical calculations and numerical simulations, require detailed information on soil characteristics and geological conditions. These essential details are often challenging to obtain in practical engineering, thereby limiting the accuracy of these methods in building construction contexts. Deep learning (DL) provides a direct approach for modeling soil deformation without having a detailed understanding of the soil properties and geological conditions. However, the existing DL algorithms mainly focus on modeling deformation directly. With advancements in monitoring technology, integrating diverse monitoring data has become crucial for accurately predicting deformation, a need often overlooked in current practices. This paper introduces a monitoring data fusion (MDF) model aimed at enhancing the utilization efficiency of diverse monitoring data. Validated against real-world engineering scenarios, this model significantly outperforms traditional single-feature and multi-feature long short-term memory (LSTM) models. It achieves a mean absolute percentage error (MAPE) of approximately 2.12%, representing reductions of 30% and 63%, and a root mean square error (RMSE) of around 12.5 mm, with reductions of 36% and 77%. Additionally, the DL interpretability method, Shapley additive explanations (SHAP), is utilized to elucidate how various model features contribute to generating predictions.

Population expansion and the development of technology have led to an increase in construction activities. In many cases, foundation grounds do not have a high enough bearing capacity and are not capable of ensuring the safe exploitation of the construction. A soil with poor mechanical characteristics must be improved using various methods, such as adding hydraulic binders (lime and cement), natural fibres, or more recently, plastic waste materials. This work aims to study the behaviour of plastic waste materials made from polyethylene terephthalate (PET) in soil improvement. Thus, the mechanical characteristics of a clay improved with shredded PET were studied. PET was added in relation to the dry mass of the clay, in percentages of 2%, 4% and 6%. The studied clay was collected from a construction site around Cluj-Napoca, Romania, from a depth of 1 ÷ 10 m. PET was provided by a local plastic waste repository. It comes from recycled water, beer and soda bottles and was cleaned using specific methods for cleaning and recycling plastic waste. PET was shredded into irregular shapes with sizes ranging from 3 mm to 12 mm and was randomly distributed in the test specimens. Compression and direct shear tests were carried out to study the compressibility and shear parameters of the improved soil (internal friction angle and cohesion). The experimental results showed an improvement in the mechanical characteristics of the clay even at a low PET addition of 2% and 4%. This method can contribute to solving two current problems of the modern world: reducing pollution by recycling plastic waste materials and using them to improve the mechanical characteristics of soil. [ABSTRACT FROM AUTHOR]

In the traditional pipe curtain construction, two steel plates, known as flange plates, are welded on both sides of the original circular steel pipe, creating a circular steel pipe with flange plates. Adjacent steel pipe with flange plates are welded together to form a new pipe curtain structure. The presentence of the flange plate cause the soil deformation law during jacking process to differ from that of circular steel pipes. In this study, Midas GTS finite element analysis software was used to simulate the jacking process of circular steel pipes with flange plates of different pipe diameters and flange plate positions. The results show that the soil settlement at the pipe top, the soil uplift at the bottom of the pipe, and the vertical displacement of the soil at the flange plate increase continuously with an increase in the spacing between the upper and lower flange plates or an increase in pipe diameter. When the top excavation surface is one section length away from the monitoring section, soil uplift occurs at the monitoring section position. When the top reaches the monitoring section position, the soil deformation becomes settlement. When the top position exceeds one section length of the monitoring section, the soil deformation tends to stablize. Meanwhile, the functional relationship between soil deformation and spacing between upper and lower flange plates, as well as pipe diameter, is obtained by fitting the curve. [ABSTRACT FROM AUTHOR]

Transmission mains (TMs) and water distribution systems (WDS) are, among the others, fundamental networks on which society relies on. Age, pipeline materials, and internal and external stresses are just few of the numerous factors that undermine the efficiency of these infrastructures and potentially reduce performance and functionality, leading to leakages or causing dangerous conditions in the surrounding environment, such as flooding or disruption. Accurate condition assessment, with suitable monitoring techniques, allows for proper management and maintenance throughout the infrastructures' lifetime. Starting from the hypothesis that leakages could be related to soil deformation, this study evaluated the opportunities offered by the differential interferometric synthetic aperture radar (DInSAR) method in identifying soil deformations in nonurban areas potentially related to leak positions along TMs. Satellite images were analyzed to derive millimetric evolution of slow deformation processes over large surfaces and a long time frame. To test the capability of the proposed method and its operability as a monitoring tool, data acquired between 2014 and 2019 by Sentinel-1 satellites, were processed to investigate two transmission pipelines located in two areas of Italy (Veneto and Toscana regions). An analysis of historical damages in the hydraulic network and soil deformations obtained by synthetic aperture radar (SAR) data examination along the pipeline path suggests how and in which conditions potential relationships between leakages along pipeline and deformations of the ground surface can be defined. [ABSTRACT FROM AUTHOR]

We examined soil‐water response in a hillslope with multi‐layered volcanic soils affected by fissures formed by intense shaking during the 2016 Kumamoto earthquake in Japan. Pressure head and volumetric water content responses in a 6 × 20 m hillslope ridgeline plot were monitored by tensiometers and capacitance‐based soil moisture sensors, respectively. The plot contained seven seismic fissures (0.3–0.8 m deep and 0.4–2.2 m wide) formed parallel to the ridgeline that exposed underlying soil layers, while areas with topsoil occurred between the fissures. Among the alternating layers, the andisol (ca. 1.0 m deep) consistently experienced high pressure heads (>−150 cm H2O) and volumetric water contents (>0.58 cm3 cm−3), indicating high water‐holding capacity. This andisol was a key layer for storing soil water and causing slow drainage into the deeper matrix, resulting in abrupt increases in volumetric water content during storms. Rainwater directly reaching the bottom of fissures without percolating through the topsoil caused rapid soil‐water response compared to the soil layer where water percolated via topsoil. Analysis of in‐situ soil water retention curves, recession rates and water storage changes revealed that the second andisol had unique characteristics for retaining water in the hillslope. The findings of this study show that spatial and temporal variability of soil water responses varied associated with earthquake‐induced fissure formation and soil water characteristics of multi‐layered volcanic soils. [ABSTRACT FROM AUTHOR]

The particle gradation seriously affects the physical and mechanical parameters and engineering properties of sandy soil. Considering the influence of particle gradation, the cone penetration test is simulated by using Particle Flow Code (PFC3D), and the results are analyzed from three aspects: cone resistance, contact force chain and soil disturbance range. At the same time, the influence of penetration velocity is analyzed. Results show that: (1) The maximum cone resistance decreases monotonically with the increase of the proportion of fine particles, and the change curve of this trend is obtained. (2) During the sinking process of the cone penetrometer, the tension zone of the force chain is mainly distributed in the free face and the soil around the cone head. The increase of the proportion of fine particles will significantly weaken the tensile effect of these two parts, and the tensile effect of the unpenetrated soil under the cone head is also significantly weakened. (3) The deformation range and contact quantity of soil increase with the growth of the proportion of fine particles, which is also the main reason for the obvious decrease of cone resistance. The maximum disturbance range of soil depends on fine particles. When the proportion of fine particles exceeds 10%, the range of disturbed soil and cone resistance are basically unchanged. (4) Without considering the influence of excess pore water pressure, the penetration velocity has little effect on the test results. [ABSTRACT FROM AUTHOR]

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Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During forest operations, canopy removal results in the soil surface being vulnerable to deformation, negatively impacting soil fertility and water quality. This study utilized unmanned aerial vehicle (UAV) photogrammetry to accurately detect soil surface deformation (SSD). Two-dimensional images were safely collected on a steep slope without real-time kinematics by conducting vertically parallel flights (VPFs). A high-resolution digital surface model (DSM) with a <3 cm resolution was acquired for precise SSD detection. Using DSM of difference (DoD), SSDs were calculated from DSMs acquired in June, July, September, and October 2022. By checking spatial distances at ground control points, errors of DSM alignments were confirmed as only 3 cm, 11.1 cm, and 4 cm from July to June, September to June, and October to June, respectively. From the first month of monitoring, erosion and deposition of approximately 7 cm and 9 cm, respectively, were detected at validation points (VPs). However, from total monitoring, cumulative SSD was assessed as having deposition tendencies at all VPs, even compared to ground truths. Although UAV photogrammetry can detect SSDs, spatial distortion may occur during UAV surveys. For vegetation growth issues, UAV photogrammetry may be unable to capture data on the soil surface itself. [ABSTRACT FROM AUTHOR]

This research presents the results of tests conducted under field conditions and included measuring the footprint of tires on soil. Two agricultural tires of the same size but different internal structures were tested, 500/50R17 (radial) and 500/50-17 (bias-ply). The factors were tire inflation pressure (0.8 bar, 1.6 bar, and 2.4 bar) and tire vertical load (7.8 kN, 11.8 kN, and 15.7 kN). The footprint made on the soil was scanned with a 3D scanner, resulting in a digital image of the tire footprint on the soil to enable an analysis of the measured parameters: length, width, depth, and contact area (in 3D form). Statistical analysis showed that for radial tire footprints, both inflation pressure and vertical load had a significant effect on all analyzed parameters. For bias-ply tire footprints, it was shown that only inflation pressure had a significant effect on all of the analyzed parameters, while the significance of the effect of the vertical load was not confirmed for the footprint depth. Based on the results obtained, the suitability of models describing the relationship between operating factors and the actual footprint area was verified. It was found that for a radial tire, the model formulated based on laboratory tests can predict the contact surface under field conditions (the correlation coefficient R2 was equal to 0.9226). In the case of a bias-ply tire, the correlation coefficient R2 reached a value equal to 0.5828. This indicates a less accurate estimation of the surface area under field conditions based on the model designed after laboratory testing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the results of the measurement of tire footprints in soil. The research was conducted under laboratory conditions using soil-filled cases. The research objects were two tires: a radial tire and a bias-ply tire of the same size. The variable parameters were vertical load (7.8 kN, 15.7 kN, 23.5 kN) and inflation pressure (0.8 bar, 1.6 bar, 2.4 bar). Test benches with a mounted tire, a soil case, and a 3D scanner were used in the research. Using the test bench, a tire was loaded with each inflation pressure, and a tire footprint was generated in the soil. Then, a 3D scanner was used to scan the tire footprint, and the parameters of length, width, depth, and tire–soil contact area (as a spatial image) were evaluated using special software. Then, mathematical models were formulated (separately for each type of tire) to describe the tire–soil contact area of the tire footprint as a function of the vertical load and inflation pressure. It was found that the depth of the tire footprint is an important parameter that influences the tire–soil contact area value. However, it was also found that with the right combination of inflation pressure and vertical load, a longer and wider, but shallower, tire footprint can be generated, the contact area value of which is similar to that of a deeper footprint. [ABSTRACT FROM AUTHOR]

The variation in road cross slope with service life affects the pavement drainage and has an adverse effect on vehicle operation safety. This paper describes a cross-slope variation prediction method influenced by the coupling effect of traffic load and soil consolidation, considering characteristics of embankment to cover the shortage for insufficient consideration of compacted embankment. First, the traffic load-induced settlement equation of a highway on soft soil foundation was introduced, which considers the effects of traffic load stress, confining pressure, soil structure, strength weakening and cyclic loading times on different positions along the cross-section. Then, the finite element model of a highway on soft soil foundations under soil consolidation is established, considering the influence of soil seepage. Finally, predictions of long-term settlement and cross-slope variation generated by coupling action of traffic load and soil consolidation were carried out with contrastive analysis with measured data. We find the following: (1) the long-term settlement was mostly from the consolidation of natural soft subsoil, while the cross-slope variation was mainly affected by traffic load; (2) variation in the cross slope of highway in soft soil areas mainly occurs within 1 year of operation. The effect of passenger cars and trucks on cross-slope variation shows diametrically opposite results, as the passenger car lane decreases while the truck lane increases; (3) the relative error of the cross-slope variation prediction results with the measured data are 2.86% and 2.5% for the left and right lane cross slopes, respectively. [ABSTRACT FROM AUTHOR]

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Due to rainfall infiltration, slope instability becomes frequent, which is the main reason for landslide disasters. In this study, the stability of slope affected by rainfall was analyzed using an indoor model test and geo-studio simulation method, and the variation law of phreatic line, seepage field, the most dangerous sliding surface, and safety factor with time were studied under rainfall infiltration. Research results showed that under the effect of rainfall, the slope failure presented a typical traction development mode. With the increase of time, the phreatic line of the slope kept rising, the water head keeps increasing, the seepage depth in the slope became deeper, and the slope stability worsened until the slope was damaged. The water head height decreased gradually from the slope left boundary to the right, and the water head width decreased gradually. The soil at the slope back edge was damaged, and the sliding soil accumulated at the slope foot, forming a gentle slope, which increased the shear strength of the slope, making the slope finally reach a stable state. In this process, the overlying soil changed from an unsaturated state to a saturated state, the pore water pressure and soil pressure increased, and then the slope was damaged, both of which decreased. Under high rainfall intensity, the slope was damaged, the soil in the slope was rapidly saturated, and the time required to produce the sliding area was short. When the rainfall intensity was the same, the smaller the slope angle was, the smaller the safety factor was. When the slope angle was the same, the greater the rainfall intensity was, the smaller the safety factor was. [ABSTRACT FROM AUTHOR]

This paper presents a case study of an investigation into the responses of the surrounding soil to the continuous jet grouting in soft soil deposits of Ningbo. During the field test, an automatic intelligent monitoring system was set up to monitor vertical and lateral displacement of ground surface, lateral displacements of the subsurface soils, and the variation of pore-water pressure induced by the installation of jet grouting piles (JGPs). The monitoring results showed that the construction of the jet grouting piles caused a large deformation of the surrounding soil. At a distance of 1.5 m from the construction area, the maximum vertical displacement and horizontal displacement could reach 179.54 mm and 180.31 mm. With the increase of distance, although the influence gradually weakened, the values of the two were still 5.8 mm and 18.98 mm at a distance of 15 m from the construction area. The excess pore pressure of the surrounding soil caused by the construction could reach 124.9 kPa. Notably, the construction of the rotary jet pile has a great influence on the surrounding soil. The installed piles can reduce the impact of the installation of the following piles. In soft soil foundation, the influence of jet grouting cannot be mitigated by stress relief holes. [ABSTRACT FROM AUTHOR]

Systematically analyzed the subsidence and groundwater level monitoring data of layerwise mark in Changzhou in the past 40 years, obtained the soil deformation characteristics before and after groundwater mining ban. From 1983 to 2005, the main contribution layers of land subsidence are the aquitard above 2nd confined aquifer(cumulative compression is 327.74 mm, accounting for 58.3%) and the 2nd confined aquifer(cumulative compression is 68.34 mm, accounting for 12.2%). From 1995 to 2001, the compression rate of the 2nd confined aquifer sand layer and the aquitard above 2nd confined aquifer decreased year by year, indicating that the consolidation of the aquifer sand layer was gradually approaching completion at the depth of the water level (70-80 m), and the aquitard also entered the secondary consolidation stage from the main consolidation stage. After the groundwater mining was banned in 2005, the groundwater level began to rise, and the aquifer sand layer and the aquitard appear to rebound. Both the aquifer sand layer and the aquitard exhibit elastic deformation, and the aquitard above 2nd confined aquifer is the main resilient layer (from 2006 to 2020, the cumulative rebound was 44.82 mm, accounting for 53.5%). From the perspective of life cycle, the life process of land subsidence in Changzhou is divided into five stages, and three critical water levels are identified, which are of great significance to the prevention and control of land subsidence and the scientific utilization of groundwater. [ABSTRACT FROM AUTHOR]

With the development of urban construction, deep foundation pit projects have been extensively studied. This paper firstly briefly explains the inverse method and then introduces the construction plan and site monitoring plan in a deep foundation pit project in Zhengzhou, Henan Province. The deformation of the surrounding soil of the deep foundation pit was monitored. It was found that the maximum deep horizontal displacement of the foundation pit was 18.39 mm on the north side, 22.98 mm on the south side, 22.67 mm on the east side, and 18.14 mm on the west side; the displacement on the southeast side was larger than that on the northwest side under the influence of the traffic road, and the displacement kept growing with the progress of the construction; the settlement of the surrounding ground surface was between 0 mm and 10 mm; when the soil of the second floor underground started to be excavated, the ground surface settlement accelerated, and the maximum settlement value was - 8.93 mm, which was smaller than the prewarning value. The results verify that the inverse construction method has a small influence on the deformation of the surrounding soil and can be widely applied in actual projects. [ABSTRACT FROM AUTHOR]

The theoretical and experimental studies have been carried out on the water and salt migration and deformation characteristics of sulfate saline soil during freeze-thaw cycles. Based on the theory of unsaturated soil mechanics and the thermoelastic continuum and considering the influence of phase change within the pore on thermodynamic and hydrodynamic parameters, the multi-physical fields coupled model of hydro-thermal-salt-mechanical in unsaturated sulfate saline soil has been established. The variation processes of the temperature field, water field, salt field, and stress field of the soil during freeze-thaw cycles were analyzed, and the validity of the theoretical model was verified by indoor experiments. The results show that there are significant attenuation and hysteresis effects when heat is transferred in the soil during freeze-thaw cycles. The water content of migration in the soil increases with the height of the soil column, while the increment of migration water content decreases with the number of freeze-thaw cycles. The formation and dissolution of salt crystals from top to bottom and the sudden increase in the salt crystallization rate are mainly caused by variations in the solubility of the salt solutions due to temperature changes. The formation and dissolution of ice and salt crystals in the soil induce expansion and contraction, and the freeze-thaw cycle conditions have a significant effect on the expansion and residual deformation of the soil. • There are attenuation and hysteresis effects in soil heat transfer during freeze-thaw cycles. • The mechanism of water migration in saline soil during freeze-thaw cycles has been revealed. • The distribution of salt in sulfate saline soil during freeze-thaw cycles is studied. • The deformation mechanism of saline soil during freeze-thaw cycles is explored. [ABSTRACT FROM AUTHOR]

Soil arching is a critical mechanism in understanding the soil-pile interaction of pile-reinforced soil slopes. Previous research primarily focuses on evaluating the arching behavior under static loading conditions, whereas the seismic response of soil arching under earthquake loading remains unclear. This paper aims to investigate the seismic arching behavior in pile-reinforced soil slopes through a series of reduced-scale shaking table tests. The soil deformation characteristics, distribution of dynamic earth pressures, and internal forces of piles were systematically analyzed to evaluate the geometry characteristics and load-transfer ability of soil arching with varying input peak ground acceleration (PGA), pile spacing, and relative density of soils. The results indicate that soil arching that grew in either a wider pile spacing or loose sand tended to fully develop under low input PGAs and exhibited a higher arching height. Following this, a practical model was proposed to predict the stable arching height. With increasing the input PGAs, the seismic arching behavior involved four stages, termed stable, transitional, meta-stable, and failure. The load-transfer ability and seismic response of piles under earthquake loading were dependent on the pile spacing and relative density of soils. A wider pile spacing gave rise to a greater load-transfer ability which was enhanced in the stable arching stage and then diminished in the subsequent stages, showing a different trend from closer pile spacings. Compared to medium dense sand, loose sand reduced the load-transfer ability, but it promoted the occurrence of stable arching and elevated the point of dynamic load application. Furthermore, in the arching failure stage, arching footholds played a crucial role in maintaining slope stability as their instability directly resulted in overall slope failure. These findings are of practical significance for the design and construction of soil slopes reinforced with piles. • Seismic response of soil arching in pile-reinforced soil slopes is experimentally investigated. • The whole-life performance of soil arching with increasing seismic intensity is measured. • Arching footholds in the arching failure stage play a crucial role in maintaining slope stability. • The load-transfer ability of soil arching in loose sand behaves differently from those in medium dense sand. [ABSTRACT FROM AUTHOR]

The numerical results of heavy equipment airdrop based on rigid ground assumption cannot accurately simulate the landing attitude of airdrop,so it is necessary to study the cushioning performance of airdrop under soil ground. In order to study the suitable condition of rigid ground,the LS-SDYNA software is used to simulate the landing process,and to compare the performance of the airdrop system under the rigid and soil ground. Meanwhile,the effect of different lateral wind velocities on the airdrop impact performance is analyzed. The results show that the difference of the maximum overload of the cargo is very small between the case of the rigid and the soil ground when the airdrop system only strikes the ground perpendicularly. The difference is much greater and the deformation effect of soil ground is significant under lateral wind conditions. Therefore,soil ground should be used for simulation with lateral wind. Under soil ground the larger of the lateral wind velocity and the initial vertical velocity,the larger of the vertical peak overload.

A unified method of predicting soil deformations induced by general and special-section tunneling in clays is proposed. Assuming that the tunneling-induced ground loss can be divided into infinite ground loss elements, and the soil deformation induced by the overall ground loss is equal to the sum of deformation due to each unit ground loss, the soil deformation due to unit ground loss is first derived based on elasticity theory solution. The soil deformation induced by random shaped-section tunneling is then obtained by integrating along the overall ground loss distribution, and the expressions are presented in the Cartesian and polar coordinate forms, respectively. By means of several cases of single circular tunneling, the reliability of the unified method is well verified through comparing with the measured data, and the performance of this method is quantitatively evaluated against the error analysis of the predictions. Taking the double-O-tube (DOT) shield tunnel for example, the unified method is further applied to predict soil deformation induced by special-section tunneling. The results show that the shape of the surface settlement curve caused by DOT shield tunneling also presents an inverted Gaussian curve. With the increase of the soil depth, the settlement of soil above the DOT shield tunnel increases slightly first and then decreases, and the settlement trough width keeps decreasing, resulting in the change of the shape of the settlement curve from “V” to “W”.

Groundwater in-situ chemical remediation is to inject remediation agents into groundwater through injection wells. The procedure includes groundwater flow, chemical oxidant transport, and soil deformation, which are coupled. Partial differential equations for soil equilibrium, groundwater continuity and mass transport were first constructed, then they were solved by COMSOL Multiphysics for a parameter sensitivity analysis and an actual case. Hydraulic conductivity, hydrodynamic dispersion, and injection pressure have significant effects on groundwater remediation, and their greater values result in a shorter time for reaching the remediation goal. The dissipation of the pore water pressure lags behind the injection stopping, which is conducive to further transport of remediation agents and improving remediation effects. Injection pressure can obviously cause soil displacement, especially in vertical direction, which is affected clearly by soil elastic modulus. It took 80 days for the entire site to meet the remediation requirement that the contaminant concentration was less than 0.6 mg/L. [ABSTRACT FROM AUTHOR]

This study aims to examine the compaction nature of shallow homogeneous soil based on the results from confined and unconfined compression tests. A plate sinkage test is employed for the experiments. A big soil bin of diameter was used for the unconfined test. Meanwhile, for the confined test, a small soil bin was constructed. A plate sinkage diameter of 200 mm was utilized to apply the load. The sensors of the diameter monitor the applied load and the resulting sinkage. The existence of a firm layer within a certain depth can remarkably influence the load-bearing capacity. This work suggests that for a rigid layer in a certain depth (shallow), the pressure and load-bearing capacity modules increase steeply. The pressure-sinkage and pressure-strain curves consist of varying parts, and there is no transition zone as a deep hard layer. Therefore, the load-bearing capacity modulus (k) is altering and not constant. The soil behavior of the unconfined test is similar to the confined test. In addition, the compaction in the unconfined test is not in a conical mass with the plate as it moves, resulting in lateral deformation.

Land subsidence is a typical geo-hazard in Cangzhou, North China Plain, having caused severe damages to transportation networks, public utilities, and other civil infrastructures. The mechanism of land subsidence and its affecting factors were revealed by theoretical model analysis, and doing geotechnical tests and monitoring of soil deformation as well as groundwater level. Theoretical analysis shows that groundwater withdrawal from both unconfined and confined aquifers can lead to land subsidence. Land subsidence of the Cangzhou Plain is mainly caused by the exploitation of deep confined groundwater. Geotechnical tests show a general trend that the compressive modulus increases with the increase of soil depth. The strata of the Upper Pleistocene and Holocene are mostly normally consolidated and partially under-consolidated, which are prone to produce large compression after pumping. Land subsidence in the Cangzhou Plain has a strong hysteresis because of seepage consolidation and creep. The deformation characteristics of strata change at different depth. The shallow aquifers are mainly elastic deformation. The area of severe land subsidence in the Cangzhou Plain is closely related to rainfall, mainly because the large amount of water are used for agricultural irrigation. InSAR results show a sudden change in regional subsidence across the Cangdong fault, which is caused by the difference in the thickness of Quaternary sediments and the difference in the deep confined groundwater level.

Pile easily develops necking defects during construction, which can limit the exertion of shaft resistance, resulting in reducing ultimate bearing capacity and creating potential safety hazards to projects. Based on transparent soil technology, this paper took the necking located in the middle part of pile shafts as an example and carried out vertical loading experiments on one intact pile and nine necking piles with caps. Then, the influences of necking length and diameter on the vertical bearing capacity were studied. The speckle field of the soil around piles was processed using the MatPIV program to investigate soil displacement. Through comparison and analysis with the intact pile, the reasons for the reduction in bearing capacity were obtained. The results show that the bearing capacity of the piles is seriously damaged by the necking. When the necking diameter is 4 mm and the necking length is 20 mm, the loss of vertical bearing capacity was 26.6%. The vertical bearing capacity decreases with the increase in necking length or the decrease in necking diameter. Pile necking makes a significant contribution to the displacement of soil around the cap. Inclined downward displacement of soil occurs near necking, which reduces the relative displacement between pile and soil and leads to the loss of pile resistance. For the necking with a large size, the soil displacement at the necking and around the pile cap is connected, which causes the displacement range of the soil under the pile cap to increase, resulting in a weakening of the exertion of shaft resistance. Subsequently, the vertical bearing capacity of piles is reduced. [ABSTRACT FROM AUTHOR]