中义隧道片理化玄武岩段大变形控制技术研究*

为进一步探究高地应力隧道软岩大变形控制技术，以中义隧道主洞片理化玄武岩段为工程背景，提出大变形Ⅰ型支护、大变形Ⅱ型支护、大变形Ⅱ型支护（围岩加固）3种大变形控制方案，以现场试验段监测为辅助验证，采用数值仿真对3种控制方案的控制效果进行对比分析。结果表明:适宜的支护成环时间具有减缓大变形的作用；在衬砌各部位累计最大变形控制方面，控制方案3较其他方案衬砌最大变形最少减小20.8%，且变形时程曲线最终收敛；围岩最大日变形量控制方面，经过开挖断面的进一步优化以及边墙部位塑性区围岩自承能力的提高，控制方案3最大日变形量较其他支护方案至少减小20.8%。结果显示控制方案3能够稳定控制片理化玄武岩大变形，且效果最好，研究结果可为类似工程提供设计依据。

Study on large deformation control technology of schistositized basalt section in Zhongyi tunnel

In order to further explore the control technology for the large deformation of soft rock in tunnel under high geostress,taking the schistositized basalt section in the main cavity of Zhongyi tunnel as the engineering background.The deformation control schemes of large deformation type Ⅰ support,large deformation type Ⅱ support and large deformation type Ⅱ support (surrounding rock reinforcement) are proposed.The monitoring of the field testing section was used as the auxiliary verification,and the control effect of three kinds of control schemes were compared and analyzed through the numerical simulation.The results showed that the appropriate time of support ring formation had the effect to slow down the large deformation.In the aspect of the cumulative maximum deformation control at each position of lining,the maximum deformation of lining in the control scheme 3 was at least 20.8% less than those in the other schemes,and the time history curve of deformation finally converged.In the aspect of the maximum daily deformation of the surrounding rock,through the further optimization of the excavation cross section and the improvement of the self bearing capacity of surrounding rock in the plastic zone of the side wall,the maximum daily deformation of support scheme 3 was at least 20.8% less than those of the other support schemes.The results showed that the control scheme 3 could control the large deformation of schistositized basalt stably with the best effect.The results can provide the design basis for the similar projects.