High Arch Dam Shape Comparison And The Improvement Of Contraction Joint Model Research

Arch dam is a kind of beautiful and high safety dam type and occupies an important position in the high dam construction,which belongs to high-order statically indeterminate structure with complex dam geometry.With increasing energy demand,the development and utilization of water resources has also entered a period of rapid development in China.The large-scale water conservancy projects constructed in recent years were mostly extra high arch dam program of 200~300m class,such as the built Jinpingyiji and Xiaowan Arch Dam.The safety performance of these high dams is extremely important,once the crash will be a major threat to the downstream people’s lives and property security and the national economy.It is very important to accurately evaluate the stress state of high arch dam due to less experience in high arch Dam engineering.Based on the actual needs of a high arch dam project in China,this paper had compiled a static analysis program for arch dams in cooperation with my instructor,and proposed an improved contraction joint model to consider the characteristics of the initial tensile strength and tangential restraint change with the keyway height.According to the basic principle of multi arch-cantilever method,the static analysis and calculation program of arch dam with five-way adjustment was compiled with Fortran language.The program can consider the influence of the deadweight load,the temperature load and the water pressure load.This program was used to analyze and compare the displacement and stress of with three kinds of arch-ring type of parabola,ellipse and logarithmic helix,and selected the relatively optimal dam type.In this paper,the normal and tangential restraint conditions are modified on the basis of the transverse joint contact model in the form of B-differential equations,and a modified contact model was proposed to consider the initial tensile strength of the transverse joint,the groove tangential shear force and the opening degree.The numerical experiments show that,on the one hand,when the upstream water level of the arch dam is low,the arch pressure in the upper part of the dam body is small and the temperature drop load may cause the arch to the tensile stress.The model proposed in this paper can make that the tensile stress be transmitted through the transverse joints in the adjacent dams by considering the normal initial tensile strength.On the other hand,since the tangential constraints of the keyways are related to the opening degree,the tangential constraints can still be provided when the transverse joints are opened.The transverse joint calculation model proposed in this paper will help to simulate the working form of the arch dam under the static load.