复合地层TBM隧道管片受力特征

在复合地层中, 全断面硬岩隧道掘进机(tunnel boring machine, TBM)在施工时由于隧道埋深较大, 开挖后的隧道周围土体应力重分布, 导致周围岩石会产生向洞内挤压而使管片受到破坏。利用大型有限元数值软件ANSYS和有限差分软件FLAC^3D对下穿地层段进行模拟, 综合分析隧道施工管片的应力、应变等, 提出合理的监测方法和保护措施。研究表明: 在仅考虑双隧道施工后地层应力重分布对衬砌管片的影响时建议双隧道同时施工, 管片位移受隧道施工的方向影响较小; 在施工过程中双隧道管片两相邻侧会发生较大水平位移, 必要时需要对管片内侧进行监测和加固等措施。

Mechanical characteristics of TBM tunnel segment in composite stratum

Based on the redistribution of soil stress around the excavated tunnel due to the large buried depth of the tunnel during the construction of the composite stratum by the full section hard rock tunnel boring machine (TBM), considering that the surrounding rocks would produce the force of squeezing into the tunnel, segment damage might occur in the tunnel construction. The large-scale finite element numerical software ANSYS and finite difference software FLAC^3D were used to simulate the underpass formation. The stress and strain of tunnel construction segments were comprehensively analyzed, and reasonable monitoring methods and protection measures were put forward. The main conclusions were as follows, when only considering the influence of stratum stress redistribution on lining segments after double tunnel construction, it was suggested that double tunnels should be constructed at the same time, and the displacement of segments was less affected by the direction of tunnel construction; In the construction process, the two adjacent sides of the double tunnel segment would have large horizontal displacement. If necessary, the inner side of the segment should be monitored and reinforced.