摘要
变质砂板岩及千枚岩等非煤系地层瓦斯涌出具有随机性、分布不均匀等特点。文章以汶马高速公路米亚罗3号隧道为工程背景,通过对该隧道地质背景、瓦斯地质特征和实测瓦斯数据的分析,研究该类地层瓦斯涌突机理及防治措施。研究表明:砂板岩类地层中的碳质成分具有一定的生烃能力;长大贯通裂隙及断层破碎带将深层的瓦斯气体导至浅层;瓦斯储存于节理密集发育带、次级褶曲转折部位及次级断层破碎带内,呈透镜状、串珠状气囊分布。施工揭穿透镜状储气蓄水构造体周围的封闭盖层,构造体内的破碎岩体、水、气就会在水压、气压作用下突然涌出,形成突出灾害。该类瓦斯成因机制复杂、预测困难,应采取超前排放、稀释、监控等综合处治措施。
The gas emission from non-coal measure strata such as metamorphic sand slate and phyllite has the characteristics of random and uneven distribution.Taking Miyaluo No.3 tunnel on Wenchuan-Maerkang highway as the engineering background,this paper analyzes the geological background,gas geological characteristics and mea⁃sured gas data regarding the tunnel,studies the mechanism and prevention measures of gas outburst in this kind of stratum.The study shows that the carbonaceous component in the sand slate has a certain capacity of hydrocarbon generation;via long and through fissures and fault fracture zones the gas is led from deeper stratum to shallow stra⁃tum;the gas is stored in densely developed joint zones,secondary bend fold zones and secondary fault fracture zones,where it is distributed in lenticular and bead-like pockets.If construction uncovers the closed cover around the lenticular gas and water storage structure,the broken rock,water and gas within the structure would suddenly gush out under the effect of water pressure and gas pressure,forming an outburst disaster.This type of gas has com⁃plex causal mechanisms and is difficult to predict,so comprehensive measures such as advance discharge,dilution and monitoring should be taken.
作者
杜毅
程强
DU Yi;CHENG Qiang(Sichuan Highway Planning,Survey,Design and Research Institute Ltd.,Chengdu 610041)
出处
《现代隧道技术》
CSCD
北大核心
2021年第4期203-209,共7页
Modern Tunnelling Technology
关键词
公路隧道
砂板岩
非煤系地层
瓦斯涌(突)出机理
防治措施
Highway tunnel
Sand slate
Non-coal strata
Mechanism of gas emission(outburst)
Prevention and control measures
