谷竹高速公路片岩隧道二衬开裂机理研究

Analysis of Cracking Mechanism for Schist Tunnel Secondary Lining of Gucheng-Zhuxi Expressway

片岩作为工程中典型的软岩,在隧道工程施工过程中常常诱发各类不良地质灾害。本文依托谷竹高速公路片岩隧道工程实例,通过对武当群片岩进行的X衍射矿物成分分析、吸水试验、崩解试验以及单三轴力学试验,发现其具有可塑性、膨胀性、流变性、易扰动性、损伤劣化、遇水软化、各向异性等特性。结合试验结果,从区域地质条件、围岩特性、地下水作用、地应力、设计施工等方面对片岩隧道二衬开裂成因进行了深入分析,揭示了片岩隧道二衬开裂机理。

Schist is a typical kind of soft rock,and schist tunnel construction often induces geological hazard.The engineering background is schist tunnel of Gucheng-Zhuxi Expressway.The behavior of Wudang schist was investigated through X-ray mineral components analysis,water absorption test（disintegration test,uniaxial test and tri-axial test.The test results show its characteristics including plasticity,swelling,rheology,being easy to be disturbed,degradation with damage,intenerate with water,and being anisotropic.The secondary lining cracking causes were comprehensively analyzed from the local geological condition,surrounding rock engineering characteristics,groundwater effect,crustal stress,construction and design.Its cracking mechanism was revealed.