小净距隧道围岩整体稳定性的下限分析

Lower Bound Limit Analysis on Surrounding Rock Mass Global Stability of Neighborhood Tunnel

小净距隧道围岩的整体稳定性分析,目前分析研究比较少。运用边坡稳定性分析适用的强度折减原理进行评价小净距隧道围岩整体稳定性,以围岩塑性区贯通、位移突变或位移超过规范值与计算不收敛3种方法综合作为围岩失稳破坏的判据。通过计算分析可知在不同的折减系数下塑性区贯通基本与位移突变同步,且早于位移超过规范值及计算不收敛。塑性区贯通为围岩破坏失稳的必要非充分条件,故采用塑性区贯通作为强度折减法判据所得为围岩整体稳定性系数的下限解。利用塑性区贯通作为判据,得到戴峪岭2号小净距隧道围岩整体稳定系数下限值约为2.7,表明该隧道具有足够安全储能。

The analysis and research of the neighborhood tunnel surrounding rock mass global in, stability are quite few at present. The strength reduction theory, which is suitable for the stability analysis of slope, is used for analysis on surrounding rock mass global stability of neighborhood tunnel, and take the transfixion of surrounding rock plastic zone, displacement excursion or surpass the standard value and calculation non-convergence problem as the criterion of rock mass unstable failure, With the analysis and calculation under the different reduction coefficient, plastic zone penetration basically with displacement excursion and simultaneously was earlier than the displacement exceeds the standard value and calcula- tion non-convergence problem. Plastic zone penetration for the necessity non-sufficient condition of the transfixion of surrounding rock plastic zone, therefore, used the plastic zone penetration to take the strength-reduction method criterion obtained for the lower limit solution of adjacent formation global insta- bility coefficient. With transfixion of surrounding rock plastic zone for the criterion of rock mass unstable failure, got the stability coefficient of Dai Yuling No. 2 neighborhood tunnel approximately is 2.7, indi- cates that the neighborhood tunnel has enough security reliability.