Field test for expansive soil slope reinforcement by covering geo-membrane on slope surface

摘要

Expansive soil is a very special soil, which swells when wetting and shrinks when drying. Wetting and drying cycle caused by repeated rain and evaporation leads to cracks development, which not only decreases the soil strength but also facilitate deep percolation of rainwater easily during infiltration, and this eventually results in slope failure. Based on the mechanism for expansive soil slope failure, a method to reinforce expansive soil slope is put forward by covering geo-membrane on slope surface, which is able to maintain soil water content to avoid cracks development, and then finally ensure the slope stability. In order to verify the effectiveness of this method, a field test was carried out. The whole test area was divided into two parts: one part was covered by geo-membrane on the surface and the other part was not. The continuous observation for about one year shows that the soil water content basically maintain constant and the soil have higher strength in reinforced area; while in unreinforced area, the water content varies caused by wetting-drying cycles, which induce cracks to grow in the soil, and the slope tends to be failure.