水工隧洞地震作用计算模型的适用性研究

针对水工隧洞在地震作用下的计算问题,对水工隧洞地震作用计算模型进行了计算对比和适用性研究。分析常用的4种计算模型用于计算水工隧洞地震作用的可行性,通过理论和数值计算确定"径向和切向反力弹簧模型"的计算参数,研究了地震作用下隧洞上方计算土体对隧洞衬砌的作用方式。结合试验验证,该方法和数值计算对比的结果表明:围岩的法向和切向弹性抗力系数受隧洞埋深、围岩类型和衬砌不同部位的影响,随埋深的增加先增大,然后趋于一个定值,围岩条件越好,数值越大,在隧洞两侧部位的数值较大;在地震作用下,隧洞上方计算土体以切向力的方式作用在隧洞衬砌的上半部分,可以通过将隧洞上部计算土体分条后进行计算。该方法可充分考虑地震对隧洞的动力和约束作用,适用于水工隧洞抗震计算。

Applicability of calculation model for hydraulic tunnel under seismic effect

Aiming at the calculation of hydraulic tunnel under seismic effect，the calculation comparison and applicability study on the calculation model for hydraulic tunnel under seismic effect are carried out herein. The feasibilities of the applications of four kinds of conventional calculation models to the calculation of hydraulic tunnel under seismic effect are analyzed，the calculating parameters of the radial and tangential reaction spring models are determined through the relevant theoretical and numerical calculations，thus the mode of impact from the calculated soil mass upon the tunnel under seismic effect on the tunnel lining is studied. Combined with the experimental verification，the result from the comparison between this method and the numerical method shows that the normal and tangential resistance coefficients of the surrounding rock are impacted by embedded depth，type of surrounding rock and the different locations of the lining，which are firstly increased along with the increase of the embedded depth，and then tend to constant values，i.e. the better surrounding rock condition is，the larger the values are to be，thus the values from both the sides of the tunnel are larger. Under the seismic effect，the calculated soil mass upon the tunnel impacts the upper part of the tunnel lining with the mode of tangential force，which can be calculated through dividing the calculated soil mass upon the tunnel into soil strips. This method can fully considers the dynamic and confining effects from earthquake on the tunnel，thus is suitable for the seismic calculation of hydraulic tunnel.