Stability Analysis Of Multi-stage Slope Supported By Prestressed Bolt

In recent decades,with the development of foundation engineering in China,prestressed bolt has been widely used in foundation pit engineering and slope support.In the slope support engineering,it is inevitable to encounter the stability problems of the slope and even the high slope.The deformation and failure modes of the slope caused by the different structure of the slope and the different physical characteristics of rock and soil mass are not the same,so the corresponding support methods are not the same.In this paper,the prestressed bolt is used to analyze the stability of multistage slope.The prestressed bolt support structure has the advantages of low cost,simple construction and short construction period.In the past theoretical research on the stability of the slope,it is often a single-stage slope,the slope structure is relatively simple,but in the actual slope engineering,often involves the multi-stage slope,in order to achieve its stability requirements,so we should strengthen the theoretical analysis and research of the multi-stage slope.In this paper,based on the log-screw failure mode,the stability of the multi-stage slope is analyzed by using the prestressed bolt support structure,and the theoretical calculation formula of the multi-stage slope safety coefficient is solved by MATLAB.At the same time,the model is established by using FLAC 3D in combination with an engineering example.The main research work is as follows:(1)Several typical failure modes of the slope are expounded,the basic principles of the prestressed bolt support structure are introduced,and the application scope and limitations of the structure are explained.(2)On the basis of single stage slope stability study,the stability of multi-stage slope is analyzed by using limit analysis upper bound method based on logarithmic spiral failure mode.The calculation formulas of the external power and internal energy dissipation rate in the system are sorted out,the stability coefficient of the slope is calculated by MATLAB language,and the corresponding stability coefficient is obtained according to different c and ?.(3)The calculation principle of FLAC 3D is introduced,and a model is built based on the parameters given by an engineering example,so as to obtain the safety coefficient of the multi-stage slope and its horizontal displacement and vertical displacement in the actual project.(4)The influences of bolt spacing,bolt inclination,slope platform width,cohesive force and internal friction Angle on the stability of multi-stage slope are analyzed.The relation curves of influencing factors and safety coefficient are drawn respectively based on the results calculated by theoretical method and the results calculated by FLAC 3D on engineering examples,and the two are compared and analyzed.The results show that there is little difference between the theoretical research and the results of engineering examples,and the curve trend is roughly the same.