叙毕铁路隧道典型施工致灾构造及地质雷达超前预报

Typical Construction Disaster-Inducing Geological Structures and GPR Advance Prediction in Xuyong-Bijie Railway Tunnels

隧道施工致灾构造是指可能导致施工地质灾害发生的不良地质体。文章根据叙毕铁路几座典型隧道的地形地貌、地层以及地质情况,归纳出可能的致灾构造有:节理密集发育破碎岩体、顺层错动破碎岩体、压性(逆)断层强烈挤压破碎带、岩溶固体(粘土、粘土夹块石、块石)充填物围岩失稳塌方致灾构造;煤与瓦斯突出致灾构造;富水压性断层上盘强烈挤压破碎带涌水、突水、突泥、洞内泥石流致灾构造;充填(水、粘土、粘土夹块石、块石)岩溶涌水、突水、涌泥、突泥、洞内泥石流致灾构造。在致灾构造分类基础上,结合地质雷达探测结果,总结出四类图像特征:“双曲包裹型”、“双线夹腔型”、“相位反向,且前后界面夹较强反射带”和“两界面夹弱射带”。本研究可为类似致灾构造预报提供借鉴。

The construction disaster-inducing geological structures in tunnelling refer to the unfavorable geological bodies that may cause construction disasters.According to the topography,stratum and geological conditions of several typical tunnels in the Xuyong-Bijie railway,this paper summarizes the potential construction disaster-inducing geological structures,i.e.1)the rock failure and collapse induced disaster structures including intensively developed fractured rock mass,bedding fractured rock mass,strong crushed compressive(thrust)fault zone,karst solid fillings(clay,clay with block stone,block stone);2)coal and gas outburst induced disaster structure;3)water inflow,mud outburst,debris flow induced disaster structures in the strong crushed fractured zone at the upper layer of water-rich compressive fault;4)water inflow,mud outburst and debris flow induced disaster structure in the karst caves filled with water,clay,rock blocks interlayered clay,block stones.Based on the classification of disaster-causing structures and the ground penetration radar(GPR)detection results,four types of typical image characteristics are obtained,i.e.the hyperbolic wrapped mode,the double-line clamped cavity mode,the mode of phase inversion and strong reflection band zone sandwiched between the front and rear interfaces,and the mode of weak reflection band zone sandwiched between two interfaces.