钢筋混凝土护面加固对重力坝地震反应影响

Seismic response of gravity dam due to reinforced concrete facing

以钢筋混凝土护面加固的丰满重力坝为研究对象,采用基于ANSYS整体式钢筋混凝土有限元法,建立代表性溢流坝段三维模型分析大坝加固前后的静动力特性.结果表明:护面加固后坝顶最大静位移量减少约14%,地震载荷下最大动位移量减少约6%;加固后地震响应更趋向平缓,峰值响应的出现迟于加固前,对抗震是有利的,但坝体顶部正向地震响应会因护面加固后刚度和质量增加而增大;护面加固能够显著地改善坝体顶部和下游坝肩部位老混凝土的应力状态,但对坝体上游坝面和坝踵部位的应力状态基本没有影响.钢筋混凝土护面对坝体抗震能发挥一定作用,但应重视坝肩和坝顶增大的动力响应对护面抗震的不利影响.

Fengman dam with reinforced concrete facing was studied, and based on ANSYS reinforced concrete finite element method, a typical 3D overflow monolith model was taken to analyze the static and dynamic behaviors dam before and after reinforcement. Results show that, after reinforcement the maximum static displacement of dam is down by about 14%, the maximum dynamic displacement of dam under earthquake is down by about 6%; the seismic responses are moresmoothly, the peak responses appearlater than that of before reinforcement, which are advantageous, however with the stiffness and mass increasing the earthquake responses of dam top increase; concrete facing reinforcement could significantly improve the old concrete stress state of the dam downstream and dam slope position, but it has little effect on the stress state of dam upstream face and dam heel. Therefore, reinforced concrete facing plays a certain role in the dam seismic resistance, however, we should pay attention to the adverse effects on reinforced concrete facing caused by the increased seismic responses of dam shoulder and crest.