跨孔声波CT技术在花岗岩球状风化体探测中的应用  

Application of cross-hole sonic computer tomography to detection of spherically weathered granite

作　　者：钟宇 陈健[1] 闵弘[1] 粟健[2] 卢松[2] 盛谦[1] 黄珏皓 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中铁西南科学研究院,四川成都610031

出　　处：《岩石力学与工程学报》2017年第A01期3440-3447,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2015CB057905);中国科学院重点部署项目;百人计划项目(KZZD–EW–TZ–12);国家自然科学基金资助项目(51409263)~~

摘　　要：花岗岩球状风化体(孤石)是花岗岩风化程度不均产生的残留,直接影响到地铁盾构施工的安全性,高效、准确地探明孤石分布是地铁工程勘察面临的难题。利用自主研制的电火花震源等探测系统和地质专家分析法,在探测区域周边的钻孔中进行震源的发射和声波的接收,根据纵波在孤石和周边地质中具有不同的传播速度等原理,通过对声波初至旅行时的记录和解译,反演成为探测区域的三维声波速度场,直观地表达了探测区域的内部地质构造。以某市地铁隧道孤石调查为实例,验证了该方法的有效性和可靠性。结果显示,跨孔声波CT技术能有效地揭示孤石的空间分布,成果图像形象直观,可较好地解决该类地质勘察难题,能够为后续施工提供科学依据。Spherically weathered granite（commonly known as the ＂boulder＂ ） is the remnant of a granite body which has been unevenly weathered. Their existence poses a serious operational risk to the subway shield tunnel construction efficient and accurate detection of boulder has been a difficult problem in geotechnical investigation for subway shield tunnel. Using self-determined sparker and geology expert analysis method, sonic wave is created and received in the drills around the detection region. By the difference of longitudinal wave＇ speed in the boulder and other geological body, first arrival time is recorded and explained, and a 3D velocity field of sonic wave is produced by an inversion algorithm, which can describe the geological structure of the detection region. Taking the boulders survey of a certain subway as an example, validity and reliability of this method is verified. The results demonstrate that the cross-hole sonic computer tomography is a very effective technique for ＂boulder＂ detection and mapping. Thus, sonic computer tomography can successfully detect similar geological investigation problems and provide scientific basis for the follow-up construction.

关 键 词：工程地质 声波CT 跨孔 花岗岩球状风化体 地铁工程勘察 

分 类 号：P631.4[天文地球—地质矿产勘探]