Research on the influence of fracture characteristics on shear strength of expansive soil
Swelling shrinkage and fissuring are the basic characteristics of expansive soil,and the internal cracks of expansive soil have a huge impact on slope failure,often causing engineering accidents.In order to study the influence of crack characteristics on the shear strength of expansive soil,Nanyang expansive soil is taken as the research object,and the effect of crack characteristics,such as dip angle,number and shape,on the mechanical properties of expansive soils were studied respectively.The CT scanning test was used to observe the development of internal cracks in undisturbed soil,and the influence of cracks on the shear strength of expansive soil was analyzed by direct shear test of fractured soil samples with different crack dip angles,numbers,shapes and fillers between different cracks.The experiment results show that the crack damages the integrity of the soil mass and decreases the shear strength.As cracks continue to develop,the intersection of cracks further damages the integrity of soils.The shear strength parameters of expansive soils(cohesion force and the interior friction angle)first decreases and then increases with the increasing crack dip angle.When the inclination angle of the fracture surface is the inclination angle of the failure surface of the expansive soil,the shear strength is the lowest.The closer the dip angle of the fracture surface is to the dip angle of the failure surface,the lower the shear strength is,and vice versa.The prediction model of shear strength index changing with dip angle is established by introducing the weakening degree of cohesion and internal friction angle of fractured expansive soil.
万方数据
维普
