Analysis Of Deep Anti Sliding Stability Of Gravity Dam

Gravity dam is the most widely used dam type in dam construction in the world.It relies on its own weight to maintain its stability.The stability analysis of gravity dam is an important subject in the design of gravity dam.Due to the complexity of geological conditions,faults,weathered fracture zones and gently inclined weak structural planes under the dam foundation may cause deep sliding of gravity dam.Based on extensive reading and analysis of relevant literature,this paper studies the analysis method of deep anti sliding stability of gravity dam.The main research contents are as follows:(1)Aiming at the deep sliding stability analysis of gravity dam with double sliding surfaces,this paper discusses the influence of resistance angle on safety factor when analyzing the deep sliding stability of gravity dam with equal safety factor method.The results show that the safety factor increases with the increase of resistance angle.it is suggested that resistance angle should be taken as 0°.according to the specification.the calculated safety factor is partial to safety.Considering the movement possibility of sliding mass block instability,the dam foundation will be cut along the middle fracture surface when the sliding mass is unstable.It is suggested that the middle fracture surface and the sliding surface have the same safety factor when the deep sliding stability of gravity dam is analyzed,which can ensure the safety and reliability of the dam and make the project more economical.At the same time,the influence of the inclination angle of the middle fracture plane on the safety factor of the deep anti sliding stability of gravity dam is analyzed.The results show that there is the most dangerous inclination angle,and it is dangerous to assume that the middle fracture plane is a plumb plane(2)Based on the finite element stress solution on the sliding surface,assuming that the normal stress on the sliding surface in the critical sliding state is obtained by the finite element stress correction,the stress distribution on each sliding surface in the critical sliding state is determined.The internal force on the sliding surface is obtained by stress integration,and then the equilibrium equation is established by considering all the equilibrium conditions of each sliding block.Then the strict limit equilibrium method for deep anti sliding stability analysis of gravity dam is given by using Pan’s maximum principle.The calculation example shows that the safety factor calculated by the strict rigid lmit equilibrium method is less than that calculated by the traditional rigid limit equilibrium method,The results are safe,and the error is within the allowable range.(3)For the complex geological conditions of dam foundation,there may not be a clear sliding surface.In order to search the position of the most dangerous sliding surface and the middle fracture surface,and calculate the minimum safety factor of deep anti sliding stability,an optimization model for calculating the minimum safety factor of deep anti sliding stability of gravity dam is established by taking the sliding surface position parameter as the design variable.Chaos Particle Swarm Optimization(CPSO)is used as the optimization method,and several typical examples are given to illustrate the rationality of the proposed model and method.(4)Based on MATLAB 2012a platform,a user-friendly calculation program for deep anti sliding stability of gravity dam is developed.