大偏压小净距隧道施工方法分析

摘要

In order to determine the reasonable construction method of small clear distance tunnel in the condition of IV grade surrounding rock,Combined with the construction of the tunnel project of Huai Tong expressway,Considering the three different combinations of the construction plan on the steps and the ring cutting method,Based on the finite element software,the different construction methods of the small spacing tunnel under the condition of IV grade surrounding rock slope are simulated,Focuses on the analysis of tunnel excavation on the surface and the surrounding rock disturbance effects,including sur-face and tunnel face and clip rock column region of the displacement and stress.The reasonable construc-tion method of the upper step down method is determined for the small clear distance tunnel of the steep slope under the condition of the IV grade surrounding rock,The analysis results can provide reference for the design and construction of a small net distance tunnel under similar conditions.%为了确定 IV 级围岩条件下陡坡小净距隧道的合理施工方法，结合怀通高速公路隧道工程施工实例，考虑上下台阶与环形开挖留核心土法的3种不同组合下的施工方案，通过有限元软件对 IV 级围岩陡坡条件下小净距隧道的不同施工方法进行了模拟，重点分析了隧道开挖对地表、围岩等的扰动效应，主要包括地表、掌子面以及中夹岩柱区域的位移和应力，确定了上下台阶法为 IV 级围岩条件下陡坡小净距隧道的合理施工方法，分析成果可为类似条件下的小净距隧道的设计、施工提供参考。