Study On The Emulation Analysis Of Danger Removing And Reinforcement On Sick-dangerous Concrete Arch Dams

With the increase of the service period, the problem, gradually aging and various dangerous sick of hydraulic engineering concrete constructions, becomes an international one step by step. As for the common problems in the sick-dangerous dam recently, abutment stability and dam bodycracks, some primary research are given in the paper, combined with the project------Study on theEmulation Analysis of Danger Removing and Reinforcement on the Sick-dangerous Concrete Arch Dams of Shuanghe, which is cooperated between Hydraulic Structure Center of Hohai University and Chendu Hydroelectric Investigation & Design Institute of SPC.Usually, there are some cracks in arch dam during construction period and operating period. In this paper, only those existing cracks and their growing are discussed. The analysis is described in two ways, stress checking and emulation analysis. Based on the marriage of finite elements method and multi-arch beam method, improving equivalent stress analysis method of arch dam is proposed and the effect of mesh size on arch dam equivalent stress is discussed in this paper. Furthermore, another new method is given in this paper that contact elements (or thin-layer elements) are located in the position of existing crack of arch dam to simulate approximately the process of cracks producing and growing. And the emulation analysis of stress and temperature fields of Shuanghe arch dam is carried out in the reservoir-empty condition and in the full-reservoir condition with this method mentioned above. On the other hand, considering characteristic of complex material of dam foundation in computation model, compatible displacement method of incompatible mesh is presented in this paper, which describes the interaction conveniently between arch dam body and dam abutment. Therefore, the mesh of dam body may be generated by 3D hexahedron elements and that of dam foundation may be generated by 3D tetrahedron elements.Moreover, based on routine research method on abutment stability, non-linear finite element iteration method is put forward in this paper, which is applied in the analysis of abutment stability of Shuanghe arch dam successfully at the same time. This method can simulate accurately soft stratums, faults and cracks in foundation, reflect the non-linear characteristics of all kinds of materials (for weak surface mainly) and yield criterion and destroy rule under the load, and take various complicated load into account such as self-weight, seepage pressure and seismic force etc.Trough the analysis of sick-dangerous mechanism on Shuanghe arch dam, some conclusions are obtained in the following: (1) Temperature drop is the main external cause of crack growing; (2) Foundation condition with soft and hard interphase is the important internal reason resulting in crack producing; (3) For the resistance and mountain body of Shuanghe arch dam is thin and weak, safety factor of abutment stability is low. On the basis of the analysis mentioned above, Chendu Hydroelectric Investigation & Design Institute of SPC advances corresponding combinatorial reinforcement and danger removing measures. Safety factor of abutment stability and stress analysis of Shuanghe arch dam strengthened are checked in this paper, and the results prove that these measures are reasonable and feasible.