水平软硬互层隧道围岩动态模拟方法及施工方法优选

Stability analysis and optimization of construction technology on tunnel excavation with soft-hard interbed rock

水平软硬互层岩体具有明显的层理效应,在数值计算时常将其近似为一种横观各向同性体.层理存在对隧道围岩特别是上部围岩稳定性具有重要影响,使得隧道开挖时拱顶下沉较水平收敛大,易发生冒顶.为此提出水平互层围岩隧道动态模拟方法,考虑层理效应下围岩持续变形,并应用于江习高速四面山砂泥互层V级围岩隧道施工,得到如下结论:1)不同方法模拟所得围岩变形结果均符合软硬互层隧道围岩变形特点,且动态模拟方法能够考虑围岩时变效应,更接近现场测试结果;2)对比不同隧道施工方法,提出了近水平软硬互层隧道的优选方案建议;3)将优选方案进行现场验证,结果显示隧道实际变形与模拟结果基本吻合.研究成果可在类似隧道施工模拟及工艺优化中推广应用.

Horizontal interbed of soft considered as a transversely isotropic and hard surrounding rock has an rock mass in numerical calculation. obvious bedding effect, it was often Bedding is important influence to the upper tunnel surrounding rock, especially the stability of surrounding rock. At the same time, Bedding has an important effect on the surrounding rock, especially the stability of the upper tunnel, which lead to a larger vault sink value than level convergence and roof fall easily when the tunnel excavation. Therefore, dynamic simulation method for the horizontal interbed surrounding rock tunnel was put forward, to consider the rock continuous deformation under the effect of bedding, then applied to the construction of Simianshan mountain tunnel surrounded with soft-hard interbed rock at the level of grade V in Jiangxi highway. Get the following conclusion： 1） The displacement results by using different simulation methods were conformed to the characteristics of surrounding rock deformation of soft and hard interbedded rock. And the dynamic simulation method can consider the time- varying effect of surrounding rock, which was closer to the field test results; 2） Compare different tunnel construction methods, the optimal scheme of near horizontal soft - hard interlayer tunnel was proposed; 3） Took the optimal scheme into practice, the simulated values approximately agree with the measured results. Research results can be promoted and it can be a good model for the similar tunnel construction simulation and optimization.