中文摘要：

运用UDEC离散元程序对直剪试验进行数值模拟,结果表明该方法可以有效模拟岩石峰后剪胀效应。运用理论分析和数值模拟试验的方法,对某一在建四线铁路车站隧道的全过程围岩特征曲线进行研究。研究结果表明：提出的＂统一围岩特征曲线＂考虑了弹塑性介质向松弛介质的过渡,运用了弹塑性支护理论、松动圈支护理论和普氏理论,反映了形变压力到松弛压力的转变,体现了不同阶段存在着不同性质的支护荷载;在岩石峰后区应使用可伸缩性支护或多次支护;盲目加大支护刚度反而会使支护承担较大的碎胀力。

英文摘要：

UDEC discrete element software was used to carry out the numerical simulation of direct shear test. Result indicates that this method can effectively simulate the shear dilation at post-failure stage of rock. The characteristic curve of surrounding rock in the overall process of one four-line railway station tunnel under construction has been studied by theoretical analysis and numerical simulation test. Results show that the proposed unified surrounding rock characteristic curve has taken into account the transition from the elastic-plastic medium to loose medium. It has applied the elastic-plastic support theory, support theory of broken rock zone and Protodyakonov^,s theory. It has reflected the transform from deformation pressure to loose pressure and different types of supporting load in different stages. It is suggested to use flexible-support or multiple-support at post-failure stage. Blindly increasing the support stiffness may make the support bear larger bulking force.