山区隧道穿越韧性剪切带的地质条件探讨

摘要

研究了山区铁路隧道穿越脆韧性剪切带(断裂带)及与其次生的韧性剪切带时设计及施工围岩分级问题.从几何、小构造、运动形迹、组构特征、构造岩、糜棱岩、同变形变质及机械作用等方面探讨韧性剪切带特征,从宏观、微观、野外研究及测试、施工类比总结其围岩分级,对比韧性剪切带(脆韧性及韧脆性)与节理密集带内岩体的工程性质及工程设计的围岩分级的异同.确定了山区隧道通过韧性剪切带时应单独研究这种无明显破裂面围岩带的分级评价因素、评价结论和围岩分级原则,设计和施工需特别注意.可供构造带复杂山区类似工程参考.%The paper solves rock mass classification problem for design and construction of a railroad tunnel through the brittle ductile shear zone (faults) and its secondary ductile shear belt in mountainous area.It discusses the characteristics of ductile shear zones including the aspects of geometry,structure,movement track,tectonic,deformation and metamorphic mylonite,and mechanical action.It summarizes the construction surrounding rock classification from the aspects of macroscopical,microcosmic,field research and testing,analog,and compares engineering properties of rock mass and engineering design of the classification of surrounding rock between ductile shear zone (brittle ductile and brittle) and joint concentrated zone.Based on these results,the paper concludes that the mountain tunnel by ductile shear zone should be studied separately,especially on rock mass classification indexes and surrounding rock classification principle.Special attention should be paid on its design and construction.