Analysis Of Local And Overall Stability Of Landslide Considering Progressive Failure

As a serious natural disaster,landslide has caused serious threat to China's economic construction and people's property security.With the advancement of mountain infrastructure construction and the severe natural geological conditions in China,the prevention and treatment of mountain landslide disasters has become increasingly important.In the construction of the project,excavation and filling will disturb the landslide that is temporarily in a stable state,and the natural factors such as rainfall and earthquake will easily cause the landslide to be destroyed.To predict and govern a landslide,you first need to analyze its stability.Due to the extensive weathering,water-weakening effect in the natural world and the strain softening characteristics of the soil itself,the soil strength parameters are reduced,which makes the development of the landslide show obvious progressive damage characteristics.The gradual failure process of landslides is often accompanied by the destruction of local soils and the attenuation of strength parameters.The stresses are redistributed and the plastic zone is continuously expanded and transmitted until a through sliding surface is formed.Therefore,considering the distribution law of soil strength parameters,analyzing the local safety factor at different locations and determining its strength reserve,it plays an important role in judging the landslide sliding mechanism and reinforcement treatment.Firstly,the related literatures and data are searched,and the displacement development law and failure characteristics of the landslide progressive failure process are summarized.The three commonly used landslide stability analysis methods,such as limit equilibrium method,strength reduction method and point safety coefficient method,are systematically expounded.The strain softening constitutive model is used to simulate the progressive failure process of the landslide.Based on the numerical analysis and the point safety factor method,the stress projection direction of the sliding zone element is considered,and the space-time evolution law of the point safety factor is obtained.Combined with the strength reduction method and the limit equilibrium method,The engineering examples compare and analyze the variation law of the comprehensive safety factor during the progressive failure of the landslide.Then,based on the strain softening constitutive model of slip zone soil,the displacement coordination deformation equation is introduced,and the local safety factor is re-established.Based on the general strip method,a calculation method of landslide stability considering the strain softening of slip zone soil is proposed.Through the engineering examples,the influence of the strain softening of the sliding zone soil on the local stability and overall stability of the landslide is considered.The results show that the local safety factor of the slope and the top of the slope is low,and the local safety factor is high in the middle of the slope.It is a typical composite landslide.Finally,according to the more common slope excavation and rainfall caused by landslide disasters,the model test is designed.Firstly,the slope foot excavation is carried out,then the rainfall effect is simulated,and the displacement-time curve of the characteristic points is combined to the landslide.The deformation and failure characteristics were analyzed during the progressive failure process.