Analysis And Evaluation On The Stability Of The Maowu Landslide

The landslide is located at about 60°to the northeast of Jiande City,Zhejiang Province.It is 35km away from the urban area of Jiande City.It is close to Tonglu County in the north,and can be directly connected through G320 national highway and Xuqi county road.According to the data of engineering geological environment and hydrogeological environment of Maowu landslide,the formation mechanism of Maowu landslide mass and the reasons of influencing stability are analyzed;The stereographic projection method is used to qualitatively analyze the joints and fissures of rocks;The limit equilibrium method is used to calculate the stability coefficient and stability degree of Maowu landslide in natural state and rainstorm state.The concept model of Maowu landslide is established by FLAC3D numerical simulation,and the stability coefficient of landslide in natural state and rainstorm state is calculated to judge its stability degree.According to the current situation and characteristics of Maowu landslide,the corresponding engineering treatment measures are proposed.The main research contents and results are as follows;(1)The overall shape of the landslide is "skip-shaped",the cracks on the slope surface are in the shape of a "feather",and the cracks at the back edge and the gullies on both sides form the landslide boundary.The main sliding direction is 295° and the upper part of the slope is gentle and the lower part is steep,with an average slope of 14° and the Maowu landslide is a small medium-sized bedding rock landslide.The factors affecting the stability of Maowu landslide include topography,lithology,and precipitation and human engineering activities.(2)Based on the topography and lithology of Maowu landslide area,the stereographic projection method is used to qualitatively analyze the rock fissures.The study area is mainly cut by two groups of joint fissures and rock occurrence.The joint fissures are:?210° ?65°;?335°?80°.The bedding angel is ?300°?40° and the current slope aspect of the slope is 295°?20°.The joints and fissures ?intersect with the landslide slope nearly vertically and belong to the favorable structural plane;Joint ?,with the bedding of landslide,inclines outward along the slope,and the structural plane inclines outward,and the intersection angle is less than the slope angle of the slope surface,which belongs to the unfavorable structural plane,and the combination is unstable,which is easy to slide along the joint fissure and bedding.(3)The stability coefficient of Maowu landslide under different working conditions is calculated by the method of limit equilibrium.The results show that the safety factor of Maowu landslide is 1.203 in natural state,which is under stable state;in rainstorm state,the safety factor of Maowu landslide is 0.993,and the landslide is in unstable state.(4)Based on the analysis of plastic zone,stress field and strain field under natural and rainstorm conditions,the deformation and failure characteristics and sliding state of Maowu landslide are analyzed by FLAC3D numerical simulation method.Through the comparison of different conditions,the calculation results show that:under natural conditions,the safety factor of Maowu landslide is 1.02,and the landslide state is not good;in the rainstorm state,the safety factor is 0.99,the stability of the landslide is reduced and in an unstable state.Compared with the results of limit equilibrium method,the two conclusions are consistent.(5)According to the basic characteristics and evaluation results of Maowu landslide,retaining engineering scheme,interception and drainage method and slope cutting and unloading method can be taken as the treatment scheme of Maowu landslide.Figure 45 Table 8 Reference 90...