Aseismatic Analysis And Optimization Design For Inlet Of Diversion Tunnel

The water control project of Xia Ban Di in Sinkiang is a large-scale hydropower project. The function of it is ecologic water compensation, spring drought supply water and generating electricity. It's the only one mountainous area water control project of Tarim basin. The collapse of diversion tunnel will result in floodwaters. Its aseismatic ability influenced on security of people and their properties. So studies on its aseismatic ability are necessary.This paper established the postulate of diversion tunnel stability analysis based on aseismatic literature of hydraulic structure in China and in the world. Its contents included aseismatic analysis methods, choosing and inputing earthquake wave, integration step, damp, boundary condition and so on.Pile foundation was needed because the geologies around diversion tunnel were complex and especially the silt layer under inlet was thick. This paper used FEM to get reasonable results of structure. The 3-D structure model was constructed with 2-node linear element for plies and 8-node solid element for the other solid structures. VADD, VGLUE, VSBV and VSBW were used to simplify the process of modeling. Efficiency was improved. Firstly, stress field and displacement field were obtained by pseudo-static. The results showed that the value of stresses and displacements at inlet of diversion tunnel were the biggest. The inlet was more dangerous than any other part. Tension stress was approach ultimate tension stress of C25 concrete, but was in the safety range, so the structure was secure. Secondly, Response spectrum analysis and time-travel analysis were used to do dynamical analysis. Regularity of stresses and displacements's changes along with time was found. The results showed that stress value was between C25 and C40 concrete ultimate tension stress. The advice was to use high-grade concrete local area. Thirdly, the results of pseudo-static and dynamical analysis showed that the influence of location of transformation joint and pile on the stresses was evidence. Optimization designs on diversion tunnel were carried out based on APDL. Reasonable design values were obtained. It provided important reference value for practical engineering.