Geogrid Reinforced Soil Retaining Wall Research Articles

Performance of Back-to-Back Geogrid Reinforced Soil Retaining Walls for Railways during Service

To investigate the performance of a reinforced soil retaining wall during service for a passenger-dedicated railway, long-term remote observation testing of the back-to-back geogrid reinforced retaining wall (BBGRSW) of Qing-Rong passenger-dedicated railway in Shandong Province was conducted for 60 months. The performance of the reinforced retaining wall was investigated after construction, and the lateral earth pressure of the reinforced soil wall was analyzed. The vertical stress on the wall and tension on the geogrid were measured using pressure cells and flexible deformation gauges, thereby resulting in the distribution of data and changes in the service period. The test results show that the pressure and deformation of the wall are almost stable. It was determined that the lateral earth pressure on the back of the wall panel was approximately 119.2% of the completion time during the 60 months after construction. The vertical stress on the reinforced soil retaining wall remained approximately stable 60 months post-construction. The maximum strain of the measured geogrids accounted for less than 30% of the peak strain. Moreover, the deformation of the wall was relatively small, which indicated that both sides of the wall remained in good condition. These research results can serve as a reference for the design optimization of reinforced soil retaining walls for high-speed railways.

Shaking Table Study on the Seismic Performance of Geogrid Reinforced Soil Retaining Walls

This study presents experimental results from shaking table tests on a reduced-scale geogrid reinforced soil retaining wall (RSRW) to investigate the seismic response of the fundamental frequency, acceleration amplification, face displacement, backfill surface settlement, and reinforcement strain under different peak accelerations and durations. The fundamental frequency is in good agreement with the predicted values. The root mean square (RMS) acceleration amplification factors increase nonlinearly with the wall height and decrease with increasing seismic load, which is not regarded as a constant value. The distributions of the peak displacement are consistent with those of the residual displacement. The combination of the sliding and rotation is observed as the predominant mode of displacement, and the rotation mode is dominant. The positions near the face (35 cm) and the ends of the reinforcement (140 cm) demonstrated larger settlement than that of the central position (70 cm and 105 cm). The reinforcement strain increased with increasing peak acceleration and maximum values measured at the central layers. The trends of the potential failure surface are similar to those of the 0.3H bilinear failure surface. The friction coefficient is nonlinearly distributed along with the reinforcements, and the maximum friction coefficient appears at the top layer (F11).

Reinforcement Strain and Potential Failure Surface of Geogrid Reinforced Soil-Retaining Wall under Horizontal Seismic Loading

This paper presents experimental results from shaking table tests on two reduced-scale geogrid reinforced soil-retaining walls (RSRWs) constructed using standard soil, modular facing blocks, and uniaxial geogrid reinforcement to investigate the distribution of the geogrid strain and the mode of potential failure surface for dynamic loading conditions. Similitude relationships for shaking table tests in a 1 g gravitational field were used to scale the specimen geometry, applied characteristics of the earthquake motions. The lateral displacement of the top model is sufficiently large for the top-model block to fall down, and the RSRW is thus destroyed. The tensile strain at the lower part is greater than that at the upper part of the RSRW. The tensile strain in different layers for two-tiered RSRW is consistent with single-step RSRW. On comparing the measured maximum tensile strain lines of the geogrid with the result of the existing calculation method of the potential failure surface, it can be observed that the existing partial calculation method is conservative. Based on the calculation methods of various potential failure surfaces and the measured data, the use of a two-tiered fold-line failure surface is proposed for the two-tiered RSRW while taking into consideration the width of the platform. And it is advised that the failure surface calculation method of BS8006 be used as the calculation method for the potential failure surface of the single-step RSRW under dynamic motion.

Static structural behavior of geogrid reinforced soil retaining walls with a deformation buffer zone

To understand the structural behavior of geogrid reinforced soil retaining walls (GRSW) with a deformation buffer zone (DBZ) under static loads, the model tests and the numerical simulations were conducted to obtain the wall face horizontal displacement, vertical and horizontal soil pressures, and geogrid strains. Results showed that compared with the common GRSW, the horizontal displacement of GRSW with DBZ decreased, and the horizontal soil pressure acting on the face panel of GRSW with DBZ increased. The vertical and horizontal soil pressures showed a nonlinear distribution along the reinforcement length, and the value was smaller near the face panel. The horizontal soil pressure acting on the face panel of GRSW with DBZ was greater than that of the common GRSW in the middle portion. The cumulative strain of the geogrid had a single-peak distribution along its length; the maximum strain of the geogrid was 0.45%, the maximum tension was approximately 29.12% of ultimate tensile strength.

Numerical Study on Seismic Performances of Geogrid Reinforced Soil Retaining Walls in Liquefiable Backfill Sand

Numerical Study on Seismic Performances of Geogrid Reinforced Soil Retaining Walls in Liquefiable Backfill Sand

Finite Difference Study on Seismic Reinforcement Force of Geo-Grid Reinforced Soil Retaining Wall

For the geo-grid reinforced retaining wall, the reinforcement mechanism of seismic behavior is unclear, and there is no reasonable standard for seismic design. A non-linear finite difference method which is based on Lagrange method was applied to analyze internal reinforcement force of geo-grid under different design parameters. The elastic-plastic model is simulated to backfill soil and foundation, and the coupled elastic parameters are used to describe the interaction of soil and geo-grid. The design parameters include geo-grid reinforcement spacing, reinforcement length, backfill soil stiffness, and thickness of panel. Some distribution characters and sensitive parameters to the internal reinforcement force of geo-grid were achieved, which will be helpful to the seismic design of geo-grid reinforced soil retaining wall with integral panel.

LRFD Calibration of the Ultimate Pullout Limit State for Geogrid Reinforced Soil Retaining Walls

AbstractThe results of load and resistance factor design (LRFD) calibration are reported for the pullout limit state in geogrid reinforced soil walls under self-weight loading and permanent uniform surcharge. Bias statistics are used to account for the prediction accuracy of the underlying deterministic models for load and pullout capacity and the random variability in the input parameters. The paper shows that the current AASHTO simplified method to calculate reinforcement loads under operational conditions is overly conservative leading to poor prediction accuracy of the underlying deterministic model used in LRFD calibration. Refinements to the load and default pullout capacity models in the AASHTO and Federal Highway Administration guidance documents are proposed. These models generate reasonable resistance factors using a load factor of 1.35 and give a consistent probability of pullout failure of 1%. A comparison with the allowable stress design (ASD) past practice shows that the operational factors ...

Field Behavior of a Geogrid Reinforced Soil Retaining Wall with a Wrap-Around Facing

Abstract The earth pressure and deformation characteristics of a geogrid reinforced soil retaining wall were monitored during and for a period of 1.5 years after construction. Both vertical and lateral soil stresses were recorded with vibrating-wire earth pressure cells, and the reinforcement deformations were measured using flexible displacement sensors. The maximum vertical foundation pressure along the wall’s reinforcements occurred at the center of the reinforcement, gradually decreasing towards the front and back ends. The measured lateral earth pressure within the reinforced soil wall is non-linear along the wall height, and the value is less than the theoretical active lateral earth pressure. The distribution of tensile strain along the reinforcements within the lower portion of the wall has two peak values. The potential failure surface of the wall closely follows the theoretical Coulomb failure surface of an unreinforced backfill.