Model tests of geotextile in collapse treatment of karst subgrade

Subgrade collapse is widespread in karst areas of south China, which is easily causing economic losses and casualties. Compared with the traditional treatment methods, using geotextile has obvious advantages in treating the subgrade after karst collapse. In this paper, two scale model tests with different laying depth of geotextile used to treat karst collapse were performed. Instrumentations and particle image velocimetry system (PIV) were applied to investigate soil pressure, vertical displacement of filling and tension distribution of geotextile. Following results were found: from the point of view of soil pressure, compared with deep buried, there had not enough stable soil under the shallow buried geotextile to improve the collapse treatment effect effectively; Compared with using deep buried geotextile, shallow buried geotextile would cause a larger overall settlement with the surrounding fill, which reduced the reinforced effect and had unsatisfactory treatment effect. Therefore, the geotextile with deep layout should be used in the collapse control and the soil beneath it should be compacted to achieve a good treatment effect.