基于监控量测的隧道围岩变形时空特性分析

Analysis of Space-time Characteristics of Tunnel Surrounding Rock Deformation Based on Monitoring Measurement

隧道开挖导致围岩应力释放与调整,围岩变形具有明显的时空特性。通过分析围岩变形机理,结合大中山2号隧道现场监控量测数据,对隧道开挖后进口浅埋偏压段围岩变形的时空特性进行了分析。结果表明:隧道进口浅埋偏压段上覆围岩变形与开挖掌子面位置及移动过程具有明显的时空特性,隧道开挖后地表横向沉降呈U字型分布,且随埋深的增加累计沉降量逐渐减小。隧道围岩变形趋于稳定时,拱顶沉降和周边收敛时间特征曲线相似,并进行了回归分析。隧道围岩变形规律的分析研究对于防治工程灾害、确定支护最佳时机、调整施工工序有重要意义。

Tunnel excavation leads to the release and adjustment of surrounding rock stress, and the deformation of surround- ing rock has obvious spatial and temporal charaeteristies. Based on the analysis of surrounding rock deformation mechanism, combined with the field monitoring data of Dazhongshan No. 2 tunnel, the space-time characteristics of the surrounding rock deformation after tunnel excavation are analyzed. The results show that tunnel entrance shallow bias section of overlying rock deformation and excavation face position and the moving process has obvious characteristics of space and time. After the tun- nel excavation, the ground suffaee settlement is U-shaped distribution, and with the increase of the depth the accumulated settlement gradually decreases. When the surrounding rock deformation tends to be stable, characteristie curve of vault set- tlement and convergence time is similar, and the regression analysis is carried out. It is significant for comprehending the law of surrounding rock deformation in detail and is propitious to prevent and cure the tunnel hazards.