Numerical analysis of reinforced soil-retaining wall structures with cohesive and granular backfills

Abstract

The failure mechanisms of reinforced soil segmental walls with extensible reinforcements were studied by performing a numerical analysis using the finite element method. The numerical approach was first verified against the results of three instrumented full-scale structures reported in the literature. Finite element models with different combinations of reinforcement spacing, reinforcement length and backfill soil were analysed. The ϕ–c reduction method, which is a special shear strength parameter reduction technique, was applied to simulate the failure conditions. The results of ϕ–c reduction analysis were used to evaluate assumptions used in current design procedures for geosynthetic-reinforced soil walls. In particular, shear strains were used to identify failure surfaces. Interpretation of the results indicated that, for both granular and cohesive backfills, the potential failure surface gradually shifts to a direct sliding mode as the system approaches failure. As a result, under working loads the potential failure surface used in current design analysis is correct, but the failure plane of a geosynthetic-reinforced soil-retaining wall at failure approaches a direct sliding type or a bilinear plane, which starts from the toe of the wall with a very shallow slope.

A Simple Analysis of Reinforced Soil Using Equivalent Approach

“…Ling and Leshchinsky [5], Hatami and Bathurst [7,8] and Guler et al [9] verified their numerical models against carefully constructed, instrumented and monitored walls. Reviews of numerical modelling of geosynthetic reinforced soil wall can be found in the papers by Bathurst and Hatami [10] and Ling [11].…”

“…8 Comparison of stress-strain curves of WGT reinforced sand (RD-40 %, r 3 -50 kPa) based on equivalent and discrete approach Fig. 9 Comparisons of stress-strain curves of WGT reinforced sand (RD-40 %, r 3 -50 kPa) using Mohr-Coulomb and Duncan-Chang model scale geogrid reinforced retaining wall constructed at Royal Military College of Canada (RMC) [7,8] and a reinforced retaining wall problem analysed by Guler et al [9] were analysed using FLAC. The equivalent numerical model is systematically verified with the instrumented data together with results from discrete approach.…”

“…Good amount of literature is available in modelling reinforced soils using numerical approaches like Karpurapu and Bathurst [1], Nakane et al [2], Rowe and Ho [3], Leshchinsky and Vulova [4], Ling and Leshchinsky [5] and Yoo and Song [6], Hatami and Bathurst [7,8], Guler et al [9] amongst many others. Ling and Leshchinsky [5], Hatami and Bathurst [7,8] and Guler et al [9] verified their numerical models against carefully constructed, instrumented and monitored walls.…”

“…Reviews of numerical modelling of geosynthetic reinforced soil wall can be found in the papers by Bathurst and Hatami [10] and Ling [11]. Guler et al [9] studied the failure mechanisms of reinforced segmental walls by finite element (FE) analysis and later Bergado and Teerawattanasuk [12] carried out numerical simulations of steel grid reinforced long embankments using finite difference method (FDM) based software, FLAC and FLAC 3D . Bathurst et al [13] studied the effect of constitutive models on the response of two full scale reinforced soil walls during construction and surcharge loading.…”

“…The model is verified with large diameter triaxial tests conducted in the laboratory with different types of reinforcements. To demonstrate the applicability and simplicity of the model, analysis is carried out for two case studies from the literature, a full scale geogrid reinforced retaining wall constructed at Royal Military College of Canada (RMC) [20] and a reinforced retaining wall problem [9]. The effectiveness and capability of the equivalent numerical analysis is systematically verified by comparing with the instrumented data and also with discrete model where the reinforcements were explicitly modelled.…”