Study On Static And Dynamic Stress And Deformation Law Of Semi-integral Gravity Dam Of Songlin Reservoir

According to the treatment of transverse joints,gravity dams can be divided into cantilever gravity dams,articulated gravity dams,semi-integral gravity dams and integral gravity dams.In general,the cantilever gravity dam is preferred as a design.When encountering a steep bank slope and unfavorable geological conditions such as weak interlayers in the dam foundation,a semi-integral gravity dam can be selected.The semi-integral gravity dam is partially grouted through transverse joints or poured to a certain elevation before joints are split,forming a structure with the bottom connected as a whole and the upper dam sections independent.It can improve the stability of the gravity dam built on bank slope or weak interlayer,and the upper part is not constrained by other dam sections,which is conducive to stress improvement.Because the semi-integral gravity dam is a dam type selection under some special conditions,there are relatively few studies on the semi-integral gravity dam at present,so it is of great significance to study the stress,deformation and stability of the dam under static conditions and earthquake action.Taking the semi-integral dam section of Songlin Reservoir as an example,this paper establishes a three-dimensional finite element static and dynamic calculation model of dam body-foundation by using ADINA finite element software,in which the dynamic calculation model imposes viscoelastic boundary.I calculated and analyzed the law of stress and deformation and anti-sliding stability of the dam under static conditions,and analyzed the law of acceleration,displacement,static and dynamic comprehensive stress and seismic safety and stability of the dam under seismic and dynamic conditions by using dynamic time history analysis method.The results of calculation and analysis show that,besides satisfying the stress and deformation distribution law of general gravity dams,there are differences due to the structural particularity of this project.(1)Under static and dynamic conditions,the displacement along the river is approximately parallel to the foundation plane in the area where the dam body is connected as a whole.(2)Under static conditions,the transverse tensile stress and the first principal stress are larger in the upstream and downstream side of the integral part of the dam body which is located in the region of steep slope.At the bottom of the dam,the transverse tensile stress and the first principal stress increase with the elevation of the foundation.The angle between the direction of the first principal stress and the vertical direction is larger.On the downstream side of the dam body which is connected as a whole,the compressive stress along the river is approximately parallel to the foundation plane.The vertical compressive stress of dam heel is larger than that of dam toe.There is a phenomenon of stress concentration at the bottom of the transverse joint,and the value of tensile stress increases obviously.Under seismic and dynamic conditions,the stress distribution law is basically similar to that under static conditions,and the stress value and distribution range increase obviously.(3)Under static and dynamic conditions,the anti-sliding stability of the dam meets the requirements and the safety and stability are improved.