Study On Three-dimension Seepage And Abutment Stability Of Jinping High Arch Dam

Jinping Water Power Station is located in the middle reaches of Yalong River that is adjacent to Muli and Yanyuan in Sichuan Province. The installed capacity of power station is 3300MW, and concrete vaulted dam is adopted. With a maximum dam-height of 305 meters, it is the highest arch dam to be built in the world. Abutment stability is the foundation for high arch dam running safely. On both abutments in the dam site, there are such geologic disadvantages as several large faults, deep cracks and rock slack, etc. Therefore, under the effect of project load and seepage, the abutment stability is a vital technical problem in the design of arch dam.In this thesis, integrated with a project of Jinping Water Power Station, the foundation seepage and abutment stability are studied systematically with 3D elastoplasticity finite element method. The main content and feature of the work are as follows:1, According to the topographic and geologic conditions of Pusiluogou, when the computation model being established, the unfavorable geologic structures, including the main faults, lamprophyre, deep cracks, joint fissures and rock slack lying on the left and right abutment, are fully considered. So the actual condition is simulated much objectively.2. For several different working conditions, with 3D finite element method, the distributing characteristic of saturation line and isobar at dam site are worked out respectively. The effect and influence of abutment stability under seepage are studied, the schemes for drainage disposal and seep preventing in favor of abutment stability are put forward as well.3.The initial geological stress of dam site is simulated.4. With 3D elastoplasticity finite element method, the stress and displacement of the dam and the base are studied under natural foundation condition. By way of safety coefficient methods of point strength and integral overload, the abutment stability is analyzed.5. With 3D elastoplasticity finite element method, the effects of different reinforcement measurements to abutment stability and arch dam structure are studied.It shows that impervious curtain and drainage adit are very useful in reducing the saturation area of abutment and the elevation of saturation line; the whole stability of abutment and downstream slope is improved effectively. Besides, the structure character of arch dam, the possible destructive parts and developed depth are revealed, which can provide warranty for the foundation disposal of arch dam. And an important conclusion is drawn out: the safety coefficient of integral overload under natural condition is 3.5, and it can be increased to 4.2 while layout of reinforcement being adopted.