Experimental and numerical study of geosynthetic reinforced soil over a channel

Geosynthetics have been commonly used as reinforcement layers to bridge over underground cavities, sinkholes, and trenches to support upper soil mass. In such applications, the geosynthetics, acting as tensioned membranes plus the effect of soil arching, maintain the stability and mitigate the subsidence of the overlying soil. This study, including a two-dimensional experimental testing and subsequent numerical simulations, investigates the subsidence of the soil mass and deformation of the geosynthetics over a roadway subdrain. The experimental study was performed in a fabricated container with 7 trapdoors (125 mm each) at the bottom. One of the trapdoors was lowered to mimic a trench for subdrain. Cylindrical aluminum bars were used as “soil” in the experimental testing to imitate the two-dimensional (2D) situations. A layer of geotextile was placed underneath the “soil fill” to serve as the reinforcement. Following the experimental test, a numerical simulation was carried out, using Discrete Element Method, PFC2D, to extend the scope of the experimental study. The results indicated that (1) the deformed shape of the geosynthetic layer is approximately parabolic, (2) the subsidence was decreased hyperbolically in the vertical direction and the lateral influence range appeared to be bounded by two lines inclined at (45° + ϕ/2), and (3) the friction angle showed significant influence on subsidence and tension in geosynthetic.