坡顶荷载作用下偏压浅埋隧道围岩稳定性分析

Stability Analysis of the Surrounding Rock of Shallow Bias Tunnels under a Slope Crest Load

文章通过构建斜坡地段浅埋隧道典型破坏模式,采用极限分析上限法,结合切线法非线性破坏准则,推导得出考虑坡顶荷载作用的斜坡地段浅埋隧道围岩压力计算式。利用MATLAB软件进行编程优化求解,重点分析了坡顶荷载和埋深比对浅埋隧道围岩压力和破坏模式的影响。研究结果表明:浅埋隧道围岩压力随岩土非线性系数增大、随水平支护反力与竖直支护反力比值减小而增大;坡顶荷载增加、埋深比增大都将降低浅埋隧道围岩稳定性;随着坡顶荷载增大、埋深比增大,浅埋隧道破坏模式向斜坡埋深较浅一侧偏转。

Based on a typical failure mode of shallow tunnels in sloping areas, the combined limit analysis upper bound method and the nonlinear failure criterion of the tangent method were used to derive the surrounding rock pressure formula of a shallow tunnel in a sloping area with consideration given to the slope crest load. MATLAB soft- ware was used to program the optimization solution, which analyzed the impact of the slope-top load and burial depth ratio on the surrounding rock pressure of the shallow tunnel and failure mode. The results show that the sur- rounding rock pressure of the shallow tunnel increases with an increase of the ground nonlinear coefficient and a de- crease of the counter-force ratio of the horizontal-to-vertical support; both the increase of the slope crest load and burial depth ratio will reduce the surrounding rock stability of the shallow tunnel; and with the increase of the slope crest load and burial depth ratio, the failure of the shallow tunnel deflects to the side of the slope, where it is relative- ly shallow.