Research On The Loading Capacity And Safety Evaluation Of High Arch Dams

A batch of world-class high arch dams has been constructed in the southwest of China, where the geological condition is complex and earthquake activities are strong. There is no mature experience of the constructon of high arch dams at home and abroad. The destruction of high arch dams will bring huge economic damage and casualties. So it is necessary to study the nonlinear dynamic response, the failure mechanism, the loading capacity and the safety evaluation of high arch dams. Based on these, a series of research are done. The main contents are as follows:(1) The simulation of arch dam-foundation system is very important to the study of dynamic response of high arch dams. Using ABAQUS finite element analysis software and FORTRAN programming, the paper realizes the application of viscous-spring artificial boundary and the input of ground motion, and analyses the dynamic response of high arch dams under fixed boundary and viscous-spring artificial boundary adopting plastic-damage model.(2) The design response spectrum is the main basis of structural seismic design and the key factor of the input of ground motion. The accumulation of new seismic records updates the attenuation relationship. The paper generates acceleration time histories (y=0.9and0.6) and studies the influence of attenuation index on dynamic response of high arch dams.(3) The failure mechanism, loading capacity, safety evaluation are the key issues in the design of high arch dams. The papar carries out the acceleration overload analysis and water pressure overload, plastic-damage model employed, according the dam body partition, and analyses the relationship of displacement, dam damge volume, damage area of dam surface and PGA. Considering linear elastic, the paper carries out the acceleration overload analysis and compares its results with the results employed plastic-damage model. The local failure evaluation considering dam body partition is studied using stress demand-capacity ratio and accumulated duration of overstress excursions obtained by the linear elasticity time history analysis.