软弱夹层对交叉洞稳定性的影响分析  

Numerical Study on the Influence of Weak Intercalation to Excavating Intersecting Tunnel

作　　者：徐彬 闫娜[2] 李宁[3] 

机构地区：[1]中交路桥技术有限公司试验中心桥隧室,北京100018 [2]北京市勘察设计研究院有限公司工程勘察所,北京100038 [3]西安理工大学岩土工程研究所,西安710048

出　　处：《地下空间与工程学报》2009年第5期946-951,971,共7页Chinese Journal of Underground Space and Engineering

摘　　要：在近水平层状的岩体开挖交叉洞,距洞顶1倍洞径的软弱夹层从交叉洞段顶部穿过,该软弱夹层既不易挖掉后回填,又难以锚固,针对这一实际工程,为研究软弱夹层对交叉洞段洞室围岩稳定的影响,应用从奥地利引进的大型岩土工程数值仿真分析软件FINAL,对交叉洞开挖进行了跟踪施工过程的数值模拟,定量对比了软弱夹层取不同强度参数和假设无软弱夹层对围岩的影响,分析了开挖过程中软弱夹层的张开情况和对围岩稳定的影响,最后结合工程经验修改了支护方案,并对比了不同方案的支护效果。结果表明,与假设无软弱夹层对比,此软弱夹层使拱顶洞壁变形增加了60%以上,拱顶围岩拉应力区和拉应力值以及支护内力增加约30%,修改后的支护方案使软弱夹层的张开减少50%以上,满足施工期稳定性要求。There is a weak intercalation going through the top of intersecting tunnels located in the layered rock mass at a distance of the tunnel diameter,it is not only difficult to be backfilled after excavation but also to be anchored to sustain stability when excavating intersecting tunnels.In order to analyse the influence of the weak intercalation on the stability of intersecting tunnels,a numerical simulation of excavating,which tracks the construction process,has been done using the large software FINAL introduced from Austria. The influence of weak intercalation on stability of the surrounding rock is compared quantitatively with that if there is no weak intercalation, then the open of weak intercalation is simulated. Finally, the support measures have been modified, and the effects of different support measures are also compared by numerical simulation. The results indicate that the weak intercalation cause increase of the deformation of surrounding rock mass upward to 60 percent and the increase of tensile stress and tensile areas and the force of supports increase by 30 percent, after adopting the modified measures, the open of weak intercalation reduces about of 50 percent and the stability of tunnels can be achieved.

关 键 词：软弱夹层 交叉洞 施工过程 数值仿真 

分 类 号：TU457[建筑科学—岩土工程]