通过建立某坝后式水电站主体结构的三维有限元模型,包括大坝、基础、坝后式厂房、厂房顶网架和支座简化模型,对比分析了在地震作用下带锚栓的板式橡胶支座、铅芯橡胶支座和铰支座3个方案对厂房上部结构的减震影响。研究结果表明:铰支座方案自振周期最短,支座节点的地震响应最大,其中厂房上、下游侧节点对最大层间位移比铅芯橡胶支座方案分别高31.74%和44.5%;铅芯橡胶支座方案由于具有较好的吸能效果,在地震作用下其本身适应剪切变形能力强,能很好地释放支座处支反力,厂房上、下游排架柱的第一主应力也是3个方案中最小的。由此可得,坝后式水电站厂房铅芯橡胶支座为推荐的支座选型方案。

A three-dimension finite element model of a power station at dam toe is built in this paper. The main structures include dam, foundation, powerhouse at dam toe, roof net, and simplified bearing model. Three kinds of bearings, namely, laminated rubber bearing supported with anchor bolt, lead rubber bearing, and hinge support, are compared to find their influence on the upper structure under earthquake action. Result reveals that hinge support is unfavorable for seismic reduction with the shortest natural vibration period and the largest seismic response; also, the maximum displacement of node pairs on the upstream and downstream side of powerhouse are higher than that in the case of lead rubber bearing by 31.74% and 44.5%, respectively. Lead rubber bearing has good ability of releasing support force under earthquake due to good energy absorption effect and better adaptation to shear deformation; moreover, the first principal stress of node pairs on upstream and downstream side of the powerhouse under earthquake is the lowest among the three cases. In conclusion, the lead rubber bearing is recommended.