Study On Some Nonlinear Problems In Analysis Of Rock Slope Stability

With the rapid development of national economy and increment of financial aids provided by government in infrastructural facilities construction, lots of high rock slope engineering problems are encountered inevitably in the fields such as railway , transportation, energy, mine, water conservancy and hydroelectric power engineering. The slope stability of rock mass has become an important and restrictive factor in construction process and security of engineering.Rock mass in nature generally is in a stable equilibrium state after suffering lengthy process of geological age. During engineering construction, the rock slope must be excavated, which releases of geological stress, and disrupts the stable equilibrium state, and makes the stress field of slope rock mass be redistributed. Such redistribution of stress field is assumed by slope rock mass itself; that is to say, slope is in an unloading mechanical state after excavation. For this type of slope rock mass excavated , corresponding mechanical model, model parameters and analysis procedure should be selected to analyze its stability.This paper aims at solving some nonlinear problems in analysis of rock slope stability by finite element method. Some key issues are researched, such as dividing the unloading zones of rock mass, the parameters of unloading fractured rock mass excavated, the computation of excavation load, and the stability of slope on the unsteady seepage owing to the excavation.The main research works of this paper are list as follows:(1) Preprocessing and post-processing of the Finite Element based on the AutoCAD are researched, an automatic mesh generation method (super-element method) and an algorithm for optimizing the node number are introduced;(2) A two dimensional nonlinear finite element program considering the compression-shear and tension-shear is written, some nonlinear questions of finite element method are listed and solved;(3) By means of acoustic wave test and in-situ deformation test of rock masses, the excavation-disturbed zone and the mechanical parameters for disturbed zone rock masses are studied;(4) This paper discusses the cause of excavation load, and gives the computation metod of excavation load; (5) The stability of slope on the unsteady seepage owing to the excavation is discussed, and then the solution is given.