Earthquakes are common geological disasters, and slopes under seismic loading can trigger coseismic landslides, while also becoming unstable due to accumulated damage caused by the seismic activity. Reinforced soil slopes are widely used as seismic-resistant geotechnical systems. However, traditional geosynthetics cannot sense internal damage in reinforced soil systems, and existing in-situ distributed monitoring technologies are not suitable for seismic conditions, thus limiting accurate post-earthquake stability assessments of slopes. This study presents, for the first time, the use of a batch molding process to fabricate self-sensing piezoelectric geogrids (SPGG) for distributed monitoring of soil behavior under seismic conditions. The SPGG's reinforcement and damage sensing abilities were verified through model experiments. Results show that SPGG significantly enhances soil seismic resistance and can detect soil failure locations through voltage distortions. Additionally, the tensile deformation of the reinforcement material can be quantified with sub-centimeter precision by tracking impedance changes, enabling high-precision distributed monitoring of reinforced soil under seismic conditions. Notably, when integrated with wireless transmission technology, the SPGG-based monitoring system offers a promising solution for real-time monitoring and early warning in road infrastructure, where rapid detection and response to seismic hazards are critical for mitigating catastrophic outcomes.

Tiered geosynthetic-reinforced soil (GRS) walls in transportation engineering are often applied in high-retaining soil structures and are typically subjected to traffic cyclic loading. However, there has been limited research on the dynamic performance of tiered GRS walls. Three reduced-scale model walls were conducted to investigate the dynamic performances of two-tiered GRS walls with different strip footing locations (d/H) under cyclic loading. The test results demonstrated that cyclic loading parameters such as average load P0 and load amplitude PA have a significant effect on the dynamic performance of the tiered walls. However, the change in loading frequency f has a minor effect on the settlement and lateral deformation when the GRS wall reaches a relatively stable state. Under the same P0 and PA, the measured maximum additional vertical stress Delta sigma v,max decreases with the increase of frequency f, whereas minimum additional vertical stress Delta sigma v,min increases. The stress distribution profile along the horizontal direction at the lower-tier wall crest is related to the strip footing location. The bearing capacity of the GRS wall increases and then decreases with increasing d/H within the reinforced zone of the upper-tier wall. The variation magnitude and distribution profile of the lateral deformations are influenced by the d/H and cyclic loading levels, especially for the upper-tier wall. When the strip footing remains in the reinforced zone of the upper-tier wall, potential slip surfaces go deeper as it moves away from the wall face. Finally, a power relationship between the calculated factor of safety and the maximum lateral deformation monitored from model tests for the two-tiered GRS walls under cyclic loading is established.

Geocells are three-dimensional, interconnected cellular geosynthetics widely used to enhance the overall strength of soils. Their foldable structure can cause variations in pocket shape during installation, depending on the extent of extension. Understanding the impact of these shape variations is essential for optimizing reinforcement efficiency and reducing the associated geocell application costs. The aspect ratio, defined as the ratio of the cell's transverse (welded) axis to the longitudinal (wall summit) axis, is proposed to evaluate the degree of extension of the most commonly utilized honeycomb-shaped geocell. A coupled continuum-discontinuum numerical method was employed to investigate the behavior of honeycomb-shaped geocell reinforced soils across various aspect ratios under confined compressive loading. The simulation results indicate that a geocell with an aspect ratio of 1.0 exhibits optimal reinforcement efficiency, and whereas reinforcement efficiency decreases as the aspect ratio deviates from 1.0 causing pocket geometries to flatten. The superior performance of rounded geocells is attributed to their enhanced ability to promote load-bearing in strong contact subnetworks. This results in denser packing structures, higher contact force anisotropy from a microscopic perspective, and greater confinement capacity against deformation from a macroscopic perspective.

A large diameter triaxial specimen of 61.9 mm was made by mixing coconut shell fibers with red clay soil. The shear strength of coconut shell fiber-reinforced soil was investigated using a dynamic triaxial shear test with confining pressure in a range of 50-250 kPa, a fiber content of 0.1%-0.5%, and a loading frequency of 0.5-2.5 Hz. The Hardin-Drnevich model based on the coconut shell fiber-reinforced soil was developed by analyzing and processing the experimental data using a linear fitting method, determining the model parameters a and b, and combining the influencing factors of the coconut shell fiber-reinforced soil to improve the Hardin-Drnevich model. The results show a clear distinction between the effects of loading frequency and fiber content on the strength of the specimens, which are around 1 Hz and 0.3%, respectively. Hardin-Drnevich model based on coconut shell fiber-reinforced soil can better predict the dynamic stress-strain relationship of coconut shell fiber-reinforced soil and reflect the dynamic stress-strain curve characteristics of the dynamic stress-strain curve coconut shell fiber-reinforced soil.

Bridges are important social infrastructure, and in particular, the stability of the back-fill behind the abutment determines the safety of the entire bridge. Recent climate change has increased the risk of flooding, and damage caused by back-fill erosion and collapse is increasing. The objective of this study is to elucidate the damage mechanism of the back-fill of bridge abutments during floods and to propose new reinforcement techniques. In the experiments, indoor open channel tests using a scaled model were conducted to verify the effectiveness of the Gabion Faced Reinforced Soil Wall (GRW), which is a reinforcement method integrating gabions and geosynthetics to reduce the collapse of the back-fill due to flooding. The result of the study showed that the GRW was effective in preventing the collapse of the back-fill due to flooding. As a result, the time until complete collapse of the back-fill was three times longer in the case where GRW was installed than in the case where no countermeasures were taken. This suggests that GRW may be effective during flood events. However, boiling due to changes in pore water pressure occurred inside the back-fill, resulting in progressive sediment discharge. In particular, the effect of the gabion installation geometry was observed, confirming that the corner design is important to control scour. This study experimentally verified the effectiveness of the reinforced soil wall and provided knowledge that contributes to improving the durability of abutment back-fill during flooding. In the future, quantitative evaluation will be conducted to establish a more practical design method.

The present document presents a review on the use of the finite element software package CODE_BRIGHT to simulate reinforced soil structures (RSS). RSS are composed of longitudinal steel or polymeric materials, placed orthogonal to the main stress direction in a soil mass, acting as tension-bearing elements. A common application of RSS is in retaining structures, in the form of reinforced soil walls (RSWs). RSW are usually designed with analytical methods, which have limited capabilities when predicting a structure's deformation response. To improve on this, the use of numerical tools allows to quantify the stress-strain response of complex, compound structures, such as RSWs. Several factors must be considered when modelling RSS, including reinforcement response, which can be non-linear under several circumstance (including time- and temperature-dependencies), soil-reinforcement interaction, soil-structure interaction, and soil response, all of which can be affected by the presence of moisture. Using laboratory measured data, the individual response of reinforcements (e.g., creep elongation), as well as the compound behaviour of soil-reinforcement material (e.g., pullout response) can be simulated to explore individual and compound response. Depending on the modelled phenomena, numerical simulations may include 2D and 3D representations. For full-scale reinforced soil walls, the stress-strain response within the soil mass, reinforcements, concrete facing panels, and connections can be studied in magnitude and distribution. Details regarding special considerations of how to model such structures with CODE_BRIGHT and other commercially available software are provided. Insights on the thermo-hydraulic repone of RSWs are covered. Advantages, limitations and future lines of research in the use of CODE_BRIGHT are explored.

Straw reinforcement improves the mechanical properties of soil matrices by uniformly incorporating dispersed straw materials, demonstrating advantages in strength enhancement, toughness improvement, and deformation control. This study aims to compare the reinforcement effects of different types of straw on soil and clarify the optimal method for straw-based soil stabilization. For wheat straw-reinforced soil using different processing methods (straw segment, straw powder, and straw ash) and mass contents, the basic geotechnical properties of each mixture were first determined. Triaxial tests were then performed under varying confining pressures and compaction conditions to assess the strength and modulus characteristics of the different reinforced soil specimens, and the microstructural characteristics of fiber-reinforced soil were investigated using scanning electron microscopy (SEM) analysis. The experimental results indicated that the strength and ductility of soils increased significantly with the addition of straw. The optimal performance of straw-reinforced soils occurred at 0.3% content. The elastic modulus increased by 85%, 64%, and 57% under confining pressures of 50 kPa, 100 kPa, and 200 kPa, respectively. At 200 kPa, straw segments provided the highest modulus increase of 57%, while straw ash achieved the greatest strength improvement of 97%. Furthermore, considering both compaction effects and cost efficiency, a compaction degree of 95% is recommended for straw-reinforced soil in engineering applications. Based on scanning electron microscopy, it was observed that the distribution characteristics of different straw types within the soil exhibit distinct patterns. This study aims to provide data to support the efficient utilization of straw materials in engineering applications.

This paper presents a new design numerical tool for geosynthetic-reinforced soil embankments, used to mitigate rockfall risk in scenarios of large volumes, energies, and multiple block failures. The model can simulate both local block penetration into the uphill embankment face and extrusion mechanism frequently affecting the downhill face. The new model is based on an existing elastic-visco-plastic model, originally developed to simulate impacts of blocks on homogeneous granular strata. The model has been enhanced and modified by incorporating a plastic mechanism, accounting for the extrusion process potentially occurring within the embankment body. The model is initially described and then validated using available in situ real-scale test data; finally, the results of a parametric study, examining the influence of the main controlling parameters and the applicability of the tool for pre-design purposes, are illustrated.

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.

Several studies focus on enhancing soil strength through the incorporation of natural or synthetic fibers. However, there is limited published data on the effectiveness of rice husk in soil reinforcement. The use of rice husk as a reinforcing material is supported by the fact that rice is one of the most produced and consumed cereals globally. In this article, we analyze the behavior of a clayey soil from southern Brazil with the addition of 0.5, 0.75, and 1% rice husk (RH), comparing it to coconut coir (CC) and curau & aacute; fibers (CU). In unconfined compressive strength tests (UCS), increases in soil strength of 20, 40, and 140% were observed for RH, CC, and CU, respectively, compared to pure soil. From consolidated undrained triaxial compression tests, both unreinforced soil and soil reinforced with 1% RH, CC, and CU were examined. The triaxial tests revealed an increase in the internal friction angle of 72 and 98%, alongside a decrease in cohesion of 57 and 94% due to the addition of CC and CU, respectively, in terms of effective stress. In contrast, RH did not significantly enhance the soil's behavior, likely due to its shorter fiber length.