小湾拱坝模拟实际横缝间距的非线性地震反应分析

本文采用Fenves接触单元模型对小湾拱坝在地震作用下的横缝非线性特性进行了细致深入的研究，内容包括有限元网格收敛性、横缝模拟间距和模拟条数收敛性、横缝灌浆强度的影响、不同水位的影响等，文章首次采用实际横缝间距和最多达到25条的横缝模拟条数对小湾拱坝进行非线性地震分析，揭示出了许多重要工程规律。Fenves关于“拱坝横缝非线性分析中只模拟3条横缝就足够了”的研究结论，对于应力分析结果尚可成立，但要得到符合实际的横缝张开度，必须在拱坝关键部位以真实间距模拟横缝，并保证一定的模拟条数。此外，不同库水位对非线性响应影响显著，应予以考虑。

Non linear seismic response analysis of arch dam with contraction joints

Based on Fenves' 3 D joint element model, a non linear analysis of the Xiaowan arch dam, having contraction joints, under the design earthquake is carried out. The convergence due to mesh size, interval and number of joints as well as the effect of grouting strength and reservoir levels are investigated in detail. There are 25 contraction joints with real interval being simulated. It is found that the Fenves's conclusion that simulation for 3 joints is enough for nonlinear analysis of arch dam is valid only for the stress result. In order to find out the reasonable joint opening at the important position of the dam, the simulation of sufficient number of contraction joints with real interval is necessary. Moreover, the reservoir level is having obvious effect on the nonlinear response of the dam.