摘要：The difficulty in landslide treatment is mainly caused by the swelling-shrinkage characteristics of swelling rock and soil.In the process of landslide,creep deformation and swelling deformation occur simultaneously in swelling rock and soil.In order to explore the mechanism of swelling rock and soil landslide,shear tests considering swelling and creep were conducted in four modes,i.e.,quick shear test and long-term shear test with natural water content,quick shear test and long-term shear test after swelling under vertical load.Our testing results show that the transient shear strength and long-term shear strength degrade rapidly when rock swells after absorbing water,characterized by the reduction in cohesion,while the angle of friction is nearly unchanged.Mechanism of swelling rock and soil landslide may be illustrated as follows.Due to the climatic wetting and drying cycles,the rock and soil underlayers of the slope undergo repeated swelling and shrinkage,leading to the gradual development of cracks in the rock and soil,which in turn accelerates the water seepage.The repaid decline in strength when swelling rock and soil absorbs water eventually induces shear failure in the slope,leading to landslide.Based on our testing results and the successful experiences in landslide treatment in Guangxi over the past decade,we proposed a few key technologies for landslide treatment,such as conducting necessary stability analysis under saturated condition,and performing in-situ large area shear test.We provided methods for stability analysis and thrust force calculation of landslide (slope) with different sliding surfaces and layers,and proposed improvement measures for prevention such as placing sand,taking into account the weather influenced depth,and casing immediately after hole digging.
关键词：Swelling rock and soil landslide;Shear test;Transient shear strength;Long-term shear strength;Key treatment technologies
