Application of geosynthetic material in capillary barriers for slope stabilisation

A capillary barrier is a soil cover system comprising a fine-grained soil layer overlying a coarse-grained soil layer. The performance of a geosynthetic material as a coarse-grained layer in a capillary barrier was investigated in this study. A sloping capillary barrier model constructed using a 0.20 m thick fine sand as the fine-grained layer and a geosynthetic material as the coarse-grained layer was investigated. Rainfall of several intensities and durations was applied to the model. The performance of the capillary barrier model was studied by measuring pore water pressures, volumetric water contents and water balance of the model. The test results indicated that the geosynthetic material used in the study was able to create a capillary break and prevent percolation into the soil layer underneath the capillary barrier model. Lateral diversion flow along the fine-grained layer (fine sand), indicating the effectiveness of the capillary barrier model, was observed during the rainfall tests.