Experimental study on shear strength behavior and numerical study on geosynthetic-reinforced cohesive soil slope

摘要

The successful application of geosynthetic reinforcement in granular soil motivates additional research into the practicality of geosynthetics in cohesive soils. The shear strength behavior of three different cohesive soils (non-, low, and medium plastic) was investigated with two types of geosynthetics (woven geotextile (WGT) and geogrid (GG)) by executing a series of triaxial compression tests with and without reinforcement. Additionally, slope stability analyses on reinforced earth slope were carried out utilizing the limit equilibrium (LE) (Slide and Slope/W), finite element (FE) (PLAXIS), and ordinary method of slices approach (analytical). The experimental results revealed that WGT was found to be more effective than GG due to higher interface friction resistance and tensile strength. The escalation in shear strength was observed 241% and 140% with four layers of WGT and GG, respectively. However, the reinforcement was found to be more efficient in non-plastic soil compared with low and medium-plastic soils in gaining shear strength. The rise in shear strength with WGT was observed 241%, 121%, and 89%, respectively, for non-, low-, and medium-plastic soils. These results indicate that strong WGT-clay interaction existed for non-plastic soil, while a weak WGT-clay interaction exists for other soil. Furthermore, FE analysis yields lower values of factor of safety than the LE analysis. The safety factor values computed from Slope/W are in excellent agreement with analytical results of LE method than Slide software. In conclusion, FEM is found to be more reliable for soil-structure interaction phenomenon which involves complex stress-strain behaviors.