Study on the Influence of Moisture Content to Shear Strength Tests for Xiashu Soil

In order to study the effect of moisture content on the shear strength of Xiashu soil, the quick shear, slow shear and repeated direct shear tests of undisturbed soil samples were carried out. The results show that when the moisture content is between 19% and 28.2%, the shear strength decreases with the increase of moisture content, but the influence of moisture content on the shear strengths in the three kinds of shear test is different. The influence of moisture content on the shear strengths in the quick shear test is larger than that in the slow shear and repeated direct shear tests. In the quick shear test, when the soil moisture content increased to 23.5%, both cohesion and internal friction angle have fallen sharply. In the quick shear test and repeated direct shear test, shear strength is mainly controlled by the cohesion. In the slow shear test, shear strength is mainly controlled by the angle of internal friction. Quick shear, slow shear and repeated direct shear tests simulated the quick-moving Xiashu soil slide, slow-moving Xiashu soil slide and the resurrection of old landslide, respectively. The test results can provide a reference and basis in the landslide control engineering.