Numerical Analysis of Static and Dynamic Behavior of Jianke Core-Walled Rockfill Dam

摘要

Jianke hydroelectric power station is in Songpan county of Aba Tibetan and Qiang Autonomous Prefecture in Sichuan Province,which belongs to mountain and ravine region of southeastern West Sichuan Plateau and northwestern Sichuan Basis. As the principal reservoir,Jianke is the first step of "One-reservoir and three-cascade" exploitation of hydropower in the Maoergai River. The project area locates on the northeast of Sichuan-Qinghai block,where the most important structure is Minjiang fault zone and Longmenshan fault zone and earthquake activity is frequent. Taking Jianke core-walled rockfill dam as study object,the static and dynamic behavior of the dam is analyzed based on 3D nonlinear FEM. The results show that the restraint function of bank slope is intense and the spatial effect is remarkable. According to the results,after completion of construction period,the maximum dam settlement is 50.73 cm,which appears in the central axis line of core wall,about 1/2 of dam height of riverbed section.Horizontal displacement distributes symmetrically. The dam stress distribution demonstrates certain arch effect.Extreme of stress level SL increases to 0.80 in storage period which appears in the lower part of upstream transitional layer.During the earthquake of ah=2.44 m/s2,the maximum displacement increases from bottom to top,the maximum in up-down stream direction is 6.3cm occurred in the center of dam crest. The maximum amplification coefficient of acceleration of the dam is 3.23. The maximum dynamic shear stress is about 150 KPa,which meets the dynamic strength requirement.Liquefaction failure could not happen for the value of dynamic pore water pressure ratio is much small than 1.0. All the indexes are in a reasonable range,which indicates that the dam has good seismic resistance stability.