This study investigates the mechanical performance and deformation characteristics of reinforced retaining walls constructed with stabilized silty clay and geogrid reinforcement. Laboratory tests evaluated the physical and mechanical properties of native silty clay, identifying its high water content and poor gradation as primary challenges for engineering applications. A stabilization method incorporating 2 % soil stabilizing liquid, 10 % densifying powder, and 4 % Portland cement was optimized to enhance clay compaction, shear strength, and compressive strength. Model experiments were conducted under varying wall configurations, including natural slopes, stabilized retaining walls, and reinforced stabilized walls with different slope ratios. Results show that the combination of stabilization and reinforcement significantly improved load-bearing capacity, minimized vertical settlement, restricted horizontal displacement, and reduced lateral earth pressure. Comparative analysis of slope ratios revealed that gentler slopes enhanced deformation resistance and reduced geogrid strain. These findings offer practical insights and theoretical support for designing efficient retaining wall systems using stabilized silty clay.

The geogrid-soil interaction, which is crucial to the safety and stability of reinforced soil structures, is determined by the key variables of both geogrids and soils. To investigate the influence of backfill and geogrid on their interface behavior of the reinforced soil retaining walls in Yichang of Shanghai-Chongqing- Chengdu high-speed railway, a series of laboratory pullout tests were carried out considering the influence of water content and compaction degree of the backfill as well as tensile strength of the geogrid. The development and evolution law of pullout force- pullout displacement curves and interface characteristics between geogrid and soil under various testing conditions were analyzed. The results showed that with increasing water content, the geogrid pullout force decreased under the same pullout displacement. The interfacial friction angle of the geogrid-soil interface showed a slowly increasing trend with increasing water content. The variation of the interfacial friction angle ranged between 9.2 degrees and 10.7 degrees. The interfacial cohesion, however, decreased rapidly with increasing water content. With increasing degree of compaction, the interfacial friction angle and the interfacial cohesion of the geogrid-soil interface gradually increased. The change of the interfacial cohesion with the compaction degree was more significant. When the degree of compaction increased from 0.87 to 0.93, the interfacial cohesion increased around 7 times. The tensile strength of geogrid has certain influence on its pullout force-pullout displacement relationship. High-strength geogrid could significantly improve the mechanical properties of the geogrid-soil interface. The investigation results can provide some reference for the design and construction of geogrid reinforced soil structures.

In this study, a flexible vertical graphene (VG) strain sensor was developed for monitoring geogrids deformation. The VG material was fabricated using radio frequency plasma-enhanced chemical vapor deposition, followed by spin-coating a polydimethylsiloxane (PDMS) solution for film curing, resulting in a flexible sensor within a PDMS substrate. The VG sensor was integrated with a wireless Bluetooth data acquisition system for automated and remote strain measurement. The stability performance of VG sensors was examined and effectively improved through cyclic loading tests in the laboratory. The drift ratio of electrical resistance before cyclic loading tests is 37.01%, which is reduced to only 0.5% after cyclic loading tests. Calibration tests show that the maximum measurement resolution and maximum measurement range of VG sensors is 0.7 micro-strain and 40000 micro-strain, respectively, indicating that VG sensors are highly effective for both high-strain resolution identification and large-strain measurement. Pullout tests demonstrate an average error of 5.67% between VG sensors and fiber Bragg grating sensors, suggesting that VG sensors are a promising alternative for large strain, wireless, and long-term geogrid monitoring.

This study conducted an experimental and numerical investigation on the stabilization of clayey subgrades using nano-silica and geogrid reinforcement. Nano-silica was incorporated in varying contents (0-4%) to assess its effects on Atterberg limits, compaction behavior, shear strength, and California bearing ratio. The results showed optimal performance at 2.5% nano-silica, with reduced plasticity index and enhanced dry density, cohesion, friction angle, and bearing capacity. A three-dimensional finite element model was developed to simulate subgrade behavior under cyclic loading, incorporating the effects of both nano-silica and geogrid layers. The model was calibrated using laboratory data to reflect observed settlement and stress distribution. The numerical results confirmed that nano-silica reduced settlement significantly up to the optimal content, while geogrid reinforcement further enhanced load distribution and reduced displacement. The combination of nano-silica and geogrid resulted in improved mechanical performance of the subgrade. These findings demonstrate the effectiveness of integrating chemical stabilization and mechanical reinforcement in clayey soils to improve structural capacity and reduce long-term deformation, providing a viable solution for pavement subgrade enhancement.

Geosynthetic-encased stone columns (GESCs) represent an efficient and cost-effective solution for enhancing weak soil foundations. The deformation and load-bearing mechanisms of GESC-improved foundations under traffic flow are complicated due to substantial particle movements and soil disruption. A three-dimensional discrete-continuum coupled numerical model was proposed in this study to investigate the cyclic behavior of GESC-improved soft soil. The reliability and accuracy of proposed model was validated through experimental data. The effect of cyclic loads, bearing stratum, and geogrid encasement was investigated. Microscopic investigation of particle movement, contact force distribution, and stress transfer mechanism was performed. The vertical loads transferred from the column to the surrounding soil with the interaction effect between the aggregates and the soil. The stress concentration ratio decreased with the increase in depth. The geogrid encasement facilitated the load transfer process by effectively confining the particles and enhancing the column stiffness. The particles in the low segment of floating column exhibited large downward displacements and punching deformation. The geogrid encasement and cyclic loads contributed to enhanced compaction and coordination number of the aggregates.

Expansive soils have significant characteristics of expansion by water absorption, contraction by water loss. Under the freeze-thaw (F-T) cycles, the engineering diseases are more significant, and the serious geotechnical engineering incidents are induced extremely easily. The aim is to investigate the mechanical response characteristics of geogrid-reinforced expansive soils (GRES) under F-T cycles. Based on a series of large-scale temperature-controlled triaxial tests, influencing factors were considered, such as the number of F-T cycles, the geogrid layers, and the confining pressure. The results showed that: (1) Friction between the expansive soil and geogrid and the geogrid's embedded locking effect indirectly provided additional pressure, limited shear deformation. With the increase in reinforced layers, the stress-strain curve changed from a strain-softening to a strain-hardening type. (2) Elastic modulus, cohesion, and friction angle decreased significantly with increasing number of F-T cycles, whereas dynamic equilibrium was reached after six F-T cycles. (3) The three-layer reinforced specimens showed the best performance of F-T resistance, compared to the plain soil, the elastic modulus reduction amount decreases from 35.7% to 18.3%, cohesion from 24.5% to 14.3%, and friction angle from 7.6% to 4.5%. (4) A modified Duncan-Zhang model with the confining pressure, the F-T cycles, and the geogrid layers was proposed; the predicted values agreed with the measured values by more than 90%, which can be used as a prediction formula for the stress-strain characteristics of GRES under freeze-thaw cycling conditions. The research results can provide important theoretical support for the practical engineering design of GRES in cold regions.

Temperature is a key factor influencing the mechanical behavior of the static interface between marine silica sand (SS) and geogrid, which directly impacts the stability and bearing capacity of reinforced soil structures. Despite its importance, there is limited research on the temperature-dependent mechanical properties of the silica sand-geogrid (SG) interface. To address this, a self-designed temperature-controlled large-scale static shear apparatus was used to perform a series of static shear tests on the SG interface, utilizing marine SS particles ranging from 0.075 mm to 2 mm and testing temperatures ranging from -5 degrees C to 80 degrees C. The results revealed a non-linear relationship between shear strength and temperature: as temperature increased from -5 degrees C to 40 degrees C, shear strength decreased, then rose between 40 degrees C and 50 degrees C, before declining again beyond 50 degrees C. The sensitivity of interface shear strength to variations in normal stress remained low at both low and high temperatures. Moreover, the interface friction angle and cohesion showed temperature-dependent fluctuations, initially decreasing, then increasing, and finally declining again. These findings underscore the complex effects of temperature on SG interface mechanics and suggest that temperature must be carefully considered in evaluating the stability and performance of reinforced soil structures under varying environmental conditions.

The study investigates the interaction between geogrids and two distinct granular backfill materials, Yamuna sand and coal mine overburden through a combination of laboratory experiments and numerical simulations. It evaluates the physical and mechanical properties of coalmine overburden and Yamuna sand, and the pullout performance of geogrid embedded in both materials. A large-scale pullout box was utilised to conduct the experiments, and the results showed that coalmine overburden offers higher pullout resistance than Yamuna sand. The effect of physical parameters such as elasticity of geogrid, geogrid geometry and angle of inclination were analysed using the discrete element method. The pullout resistance of geogrids mainly depends on the elastic properties of the material. The study also shows the existence of an optimum spacing between longitudinal and transverse ribs.

This study investigates the mechanical response and performance of biaxial polypropylene geogrid specimens cyclic loading. This work assesses the influence of embedment depths and subgrade strengths on the of geogrids. The experimental program involved subjecting the geogrid specimens to 100 repeated tensile loading cycles at four distinct load targets: 20%, 40%, 60%, and 80% of the geogrid ultimate tensile strength. The analysis focused evaluating the effects of preloading factors such as California Bearing Ratio (CBR) values, embedment depth, and the response to cyclic testing. Results show trends in stiffness reduction and changes in damping ratio with increased number of cycles. A comparative analysis was conducted with a control specimen from the same batch, highlighting the difference in mechanical response attributed to precycling variables. The findings indicate that the overall mechanical behavior of recovered geogrids is comparably consistent with new geogrids. However, variations in strain and stiffness reduction were observed among the recovered specimens, suggesting a pattern of yielding before failure. The findings suggest a minimal effect of embedment depth on the damping ratio at lower CBR. Overall, it was found that precycling and subgrade conditions have minimal effect on the mechanical response of the recovered specimens when tested in isolation.

The use of recycled polyester (rPET) in construction materials offers significant benefits, including energy conservation, cost reduction, and decreased solid waste. This study compares the performance of rPET with that of virgin polyester (vPET) products. Therefore, two main testing programs including pull-out tests and creep performance tests were carried out in order to determine the interfacial properties of the geogrid-reinforced soil and time-dependent manner of the geogrids, respectively. Broadly speaking, this study showed that the performance of rPET geogrid is comparable with vPET geogrids. Pull-out tests revealed that pull-out resistance of both vPET and rPET geogrids were roughly the same and the vPET geogrid mostly had lower dilation angles in comparison with rPET. Moreover, based on the performance creep tests, it was understood that the long-term mechanical behaviour of rPET does not differ from the long-term behaviour of vPET products.