Nonlinear Simulation of Cracks for Sick-dangerous Arch Dam with Mixed Finite Element Contact Method[1]

Ren Hao^②,Li Tong-chun^③,Chen Hui-fang^②, Zhao Lan-hao^②

②College of Water Conservancy and Hydropower Engineering,HoHai Univ.,NanJing 210098,China,Email:renhaohhu@163.com

③College of Water Conservancy and Hydropower Engineering,HoHai Univ.,NanJing

210098,China,Email:ltchhu@163.com

Abstract A new simple and efficient method is proposed in this paper for whole process simulation of crack genesis and expansion from the construction to operating period with considering the construction process of arch dam and temperature load. In the calculation mesh, the contact surface of pair nodes is located at the actual measured position of the crack. A new effective iterative method—Mixed Finite Element Method for contact problems with friction and initial gaps is used for nonlinear emulation analysis of cracking process. The system of forces acting on the structure was divided into two parts: external forces and contact forces. The displacement of structure was chosen as the basic variable and the nodal contact force in possible contact region under local coordinate system was chosen as the iterate variable, so that the nonlinear iteration process was only limited in the possible contact surface and much more economical. This method is used to simulate the cracking process of a sick-dangerous arch dam named ShuangHe arch dam in SouthWest China. In order to prove the validity and accuracy of this method, two schemes were designed as follows: According to the actual measured position and number of the cracks, the contact surfaces of pair nodes are located at the finite element mesh of the dam in SchemeⅠ.Based on the contact surfaces located in schemeⅠ, another more contact surfaces are set in the positions where the crack is not exist actually in schemeⅡ. The results show that the generated time and opening area of the cracks, calculated by this method at schemeⅠ, is match up to the actual measured data of the cracks. In schemeⅡ, the cracking numbers and position of the contact surface is basically similar with schemeⅠ, and the additional contact surfaces is not cracked. The comparison results of two schemes indicate that this method is completely feasible to analyze the crack genesis and expansion of sick-dangerous arch dam

Keywords sick-dangerous arch dam, mixed finite element method, contact element, crack, emulation

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This work is supported by the Natural Science Foundation, with the project number of 90510017.