【摘要】 地震作用下重力坝的坝踵裂纹及其稳定性是工程界普遍关心的问题。本文基于比例边界有限元法(SBFEM)研究重力坝坝踵裂纹的动态应力强度因子(SIF)的变化规律。SBFEM的优点是可以给出位移场沿径向的解析解,直接按定义求出SIF,而不必对裂尖进行特殊处理。以柯依那(Koyna)重力坝作为算例,进行了频域法和时域法的分析,比较了不同坝踵裂纹长度的应力强度因子,计算了地震应力沿坝基交界面的变化。同时计算了裂纹内水压分布对应力强度因子的影响。计算结果表明随着裂纹长度的延伸,I型应力强度因子的峰值逐渐增大;裂纹内水压力越大,对应力强度因子的影响越大。本文提出的分析方法可应用于对重力坝抗震安全性评价。更多还原

【Abstract】 Based on the scaled boundary finite element method(SBFEM) the variation of the dynamic stress intensity factors(SIF) at the heel of gravity dams subjected to earthquake excitation is analyzed.The SBFEM has the advantage that the displacement field along the radial direction can be solved analytically and the SIF is determined directly from its definition so that no special crack tip treatment is needed.The Koyna gravity dam is analyzed as an numerical example for demonstration.The time domain and frequency domain analysis are carried out.The SIFs for different length of cracks at dam heel are evaluated and the variations of stress along the dam foundation interface are calculated.In addition,the effect of the water pressure distribution inside the crack is also studied. The results show that the maximum value of K_Ⅰ varies distinctly with the increase of crack length.Furthermore,the SIF tends to increase with higher internal water pressure of crack.The proposed analysis method is useful for aseismic safety evaluation of gravity dam.更多还原