深埋隧道大超挖围岩力学响应分析

隧道爆破开挖过程中的超欠挖问题是隧道工程中普遍存在的现象，大超挖问题严重影响了隧道工程的造价投资及安全使用。本文以某隧道工程为例，利用数值模拟的方法，研究了隧道埋深和超挖厚度对围岩力学响应的影响规律。研究表明，在不同埋深条件下，围岩最小等效应力出现在拱顶位置，最大等效应力出现在拱脚位置。隧道拱顶位置的变形量最大，拱脚位置的变形量最小。相同超挖厚度对应的等效应力值随隧道埋深的增加而增大；相同位置围岩的变形量随埋深的增加而增大。另外，超挖厚度对围岩的力学响应影响较小，隧道埋深对围岩等效应力的影响较大。本研究成果可为同类工程提供借鉴。

Analysis on Mechanical Responseof Surrounding Rock Caused by Large Over-excavation in Deep Buried Rock Tunnel

As a common phenomenon, over excavation and under excavation exist in the process of tunnel blasting excavation, which seriously affects the investment and safety in tunnel operation. This artic taking a tunnel project as an example, the influence of tunnel depth and overcut thickness on mechanical response of surrounding rock is studied by numerical simulation. The results show that the minimum equivalent stress of surrounding rock occurs at the top of the arch and the maximum equivalent stress occurs at the foot of the arch with different tunnel depth, as well as the deformation of the tunnel vault is the largest and the deformation of the arch foot position is the smallest. The equivalent stress of surrounding rock increase with the enlargement of tunnel buried depth under the same condition of over excavation thickness, and the greater the buried depth of the tunnel at the same location, the greater the deformation of surrounding rock. In addition, the thickness of over excavation have a little influence on the mechanical response of the surrounding rock, but the influence of tunnel depth on the equivalent stress of surrounding rock is larger. This study can provide reference for the similar projects.