Three-dimensional Slope Limit Analysis Method Considering The Prestressed Anchor Cable And The Application Research

ABSTRACT:Slope stability analysis is an important research area in geotechnical engineering. The rigid body limit equilibrium analysis is the main method in slope stability analysis which is a simple method with clear physical meaning, and has a wide application in engineering. However, the slope stability analysis in practice is actually a three-dimensional problem, which should be analyzed with three-dimensional stability analysis methods. In addition, reinforcement measures are often adopted in slopes with low safety, and pre-stressed anchor cable is widely used in slope reinforcement especially for rock slopes for its obvious reinforcement effect. In the two-dimensional stability analysis of slope with anchor, the anchor cable is often simplified as a unit width anchoring force in calculating, while the arrangement of the anchor cable in practical is often presented in three-dimensional characteristics, therefore, the simplified processing cannot response the actual situation.In slope stability analysis with anchor, it is necessary to study the three-dimensional limit analysis method considering the three-dimensional property of pre-stressed anchor cable.In this paper, the improvement three-dimensional limit analysis method considering the three-dimensional property of pre-stressed anchor cable is proposed based on the above analysis, and the relative discussion and engineering application research has been carried on. The main work is as follows:(1) The main work in the field of limit equilibrium analysis of slope studied by the relevant scholars in recent years is reviewed and summarized, and a simple discussion on the applicability of various analysis methods and the advantages and disadvantages of them is made.(2) The basic theory and calculation method of the three-dimensional limit analysis in slopes proposed by our research team in recent years is introduced. The improvement has been carried on this, and the three-dimensional limit equilibrium analysis and upper and low limit analysis method considering the three-dimensional property of pre-stressed anchor cable is proposed, and the related calculation formula was deduced.(3) The deposit before the left bank reinforcement project in Xiaowan dam is taken as an example, and different anchor cable layout scheme is designed to verify the proposed improved method, and three-dimensional reinforcement effect of pre-stressed anchor cable is discussed based on the improved method. (4) The comprehensive analysis is carried on for Hunan and Wujiang landslide in normal storage of level254m condition of old reservoir and the normal storage of level313m condition of expansion reservoir, using the two-dimensional rigid body limit equilibrium, the three-dimensional rigid body limit equilibrium and Flac3D finite difference method and the reinforcement scheme of pre-stressed anchor cable is proposed. Stability analysis of slopes is carried out by the three-dimensional limit equilibrium analysis considering the three-dimensional property of pre-stressed anchor cable. The deformation and stability of the slope are analyzed and validated before and after adding anchor using Flac3D finite difference method. The results show that the pre-stressed anchor cable can have good reinforcement effect on slopes.