【摘要】 经典弹性力学中圣维南原理采用解析的方法计算出隧道开挖的影响范围约3倍开挖宽度,这一结论被广泛应用于隧道静力数值计算中。在隧道地震动力时程计算中,计算边界的取值范围除了受到隧道结构的影响,还与边界条件、地震波的输入等其他因素相关,目前学术界还没有较为一致的认识,更没有解析解能计算出动力边界的取值范围。该文利用Flac3D有限差分程序,对不同边界的隧道模型进行动力计算。结果表明:围岩应力值受边界取值范围影响小,围岩位移值受底边界取值范围影响大;并且地震动力计算边界取值大于8倍隧道开挖宽度时,围岩应力及位移受边界取值范围影响可以忽略。研究结论可供隧道动力分析参考。更多还原

【Abstract】 According to Saint-Venant’s principle in classical mechanics of elasticity,tunnel excavation may affect a domain with 3 times the width of excavation,and the conclusion has been widely used in static analysis of tunnel.In the calculation of earthquake dynamic time-history,the model boundaries are not only dependent on the dimension of tunnel structure,but also influenced by the input seismic waves and other related factors.Regarding the dynamic boundary of tunnel model,there has been no consensus,and also no analytical solution can be used.The finite difference software Flac3D adopted to analyze the tunnel models with different boundary ranges.Results show that the boundary has little effect on the stresses of the surrounding rock,while the bottom boundary has an obvious influence on the displacements of surrounding rock.When the boundary of tunnel models has a 8 times width of tunnel excavation in the earthquake dynamic calculations,the boundary effect on the displacement and stresses of surrounding rocks may be ignored.The conclusion may be used as a guideline for future dynamic analysis of tunnels.更多还原