列车荷载下跨地裂缝地铁隧道围岩土压力分析

Soil Pressure of the Surrounding Rock for a Subway Tunnel across Ground Fissures under a Train Load

文章根据相似理论设计了跨地裂缝地铁隧道-地层动力相互作用模型试验,通过对模型试验结果的分析系统研究了以不同分段形式跨越地裂缝的马蹄形地铁隧道在列车荷载作用下的围岩土压力以及围岩与隧道衬砌结构的接触压力。通过对相关试验数据分析,可以得到以下结论:分段隧道在地裂缝上盘没有产生下降活动时,围岩土压力与整体式隧道工况相差不多,但地层下降以后,产生的附加土压力与整体隧道工况相差较大;分段隧道在地裂缝活动下产生的附加土压力比地裂缝未活动前有所增大;尽管如此,两种隧道模式下地裂缝活动所产生的接触压力的分布和大小都比较接近,但上盘下降以后,位于上盘地层中的Y_1列土压力由于地裂缝活动脱空导致数值上比处于下盘地层的Y_2列土压力有了较大幅度的减小。

Based on the similarity theory, a model for the dynamic interaction between the stratum and a subway tunnel across ground fissures was designed. Based on an analysis of the model test results, the soil pressure of the surrounding rock and the contact pressure between the rock mass and tunnel lining structure under the train load were systematically studied with respect to a horseshoe-shaped subway tunnel across ground fissures in different ways. After analyzing the relevant test data, the following conclusions were determined： 1） if no settlement occurs at the hanging side rock of the ground fissure, there is not a big difference between the soil pressure of the rock mass of a multi-section tunnel and that of an integral tunnel, otherwise there is a big difference between them; 2） as for a multi-section tunnel, the additional soil pressure with ground fissures is larger than that without any ground fis- sures; and 3） as for the two kinds of tunnels, the distribution and magnitude of the contact pressure produced under the action of ground fissures are very close, but the soil pressure in column Y1 of the hanging side decreases largely due to voids caused by ground fissure action compared with the soil pressure in column Y2 at the heading side.