小净距公路隧道小导管注浆工艺对围岩稳定性影响的有限元分析

利用Ansys有限元软件,对大跨度小净距隧道浅埋段施工过程中的小导管注浆措施的加固效果进行了数值模拟分析,揭示了施工过程中加固措施对隧道周边变形和初期支护结构的影响.研究结果表明:地表的沉降值和地层特征点的位移都有不同程度的减小,初期支护结构的弯矩最大值减小约20%～25%,加固措施对于围岩的稳定,特别是对中岩柱的稳定有及其重要的影响,加固效果主要体现在隧道下台阶的开挖过程中.分析方法和计算结果对小净距隧道设计、施工具有一定的参考价值.

Finite Element Analysis of Small Duct Grouting Effect on Surrounding Rock Stability at Small Interval Highway Tunnel

Using FEM software ANSYS, the effect of small duct grouting reinforcing measures on the construction of large span shallow tunnel with small interval is analyzed. The influence of the reinforcing measures on the displacement of surrounding rocks and the initial supporting structure during construction is evaluated. The results show that, ground surface settlement and displacements of the characteristic positions of the ground decreased in a certain extent, and the maximum moment of the initial supporting structure reduces about 20%~25%. Furthermore, the reinforcing measures are very important to the stability of the surrounding rocks, especially to the middle wall, and the effect of reinforcing is embodied in the process of excavation of the lower bench. The analysis method and conclusion at present may provide some references for the design and construction of small interval tunnels.