综合物探方法在黏土地区开挖隧道的应用  

Application of Comprehensive Geophysical Prospecting Method in Tunnel Excavation in Clay Area

作　　者：吴庆良 唐彬雪 王惠贤 WU Qingliang;TANG Binxue;WANG Huixian(College of Engineering and Technology,Southwest University,Chongqing 400715,China;China Merchants Chongqing Communications Technology Research and Design Institute Co.Ltd.,Chongqing 400067,China)

机构地区：[1]西南大学工程技术学院,重庆400715 [2]招商局重庆交通科研设计院有限公司,重庆400067

出　　处：《西南大学学报（自然科学版）》2023年第6期192-200,共9页Journal of Southwest University(Natural Science Edition)

基　　金：重庆市自然科学基金项目(2022NSCQ-MSX3761);中国博士后科学基金项目(2019M660022XB).

摘　　要：土体受水的影响大,在黏土隧道中,随着含水率的增加,隧道围岩逐渐失去自稳能力,失稳的可能性增大.利用土体含水率与电阻率的关系,采用结合AGI高密度电法、EH4大地电导率法的综合物探方法对重庆一隧址区隧道的失稳现象进行探测,并推断导致黏土含水率高的原因.结果表明:河床下方区域的电阻率较低,且低电阻率区域沿河道走向分布,自上而下逐步增加,此时河床下方的黏土含水率由远及近越来越高.已知隧址区处于易汇水区域,根据地调结果排除原有地下水的影响,验证推断:造成河床下方黏土含水率较高的原因是隧址区破碎带的存在,水流沿地表与地层间的导水通道进入地下,增加了黏土层的含水率.向河底注入水泥浆,与原有黏土体形成水泥土,通过这种方式改善土体性能并做到防渗以减少黏土受水影响引起的失稳问题.The soil properties are greatly affected by water.In clay tunnels,with the increase of water content,the surrounding rock of the tunnel gradually loses its self-stability and the possibility of instability increases.Based on the relationship between soil moisture content and resistivity,this paper uses the comprehensive geophysical prospecting method combined with AGI high density resistivity method and EH4 earth conductivity method to detect the instability of tunnels in a tunnel site in Chongqing,and infer the causes of high moisture content of clay.The results of comprehensive geophysical prospecting methods show that the resistivity of the area below the riverbed was low,the low resistivity area was distributed along the river channel and increasing gradually from top to bottom.At same time,the clay moisture content below the riverbed was increasing from far to near.It is known that the tunnel site area is in the catchment area.The influence of the original groundwater was excluded according to the site survey results.It is verified that the reason for the high water content of the clay under the riverbed is the existence of the fracture zone in the tunnel site area.The flow enters the underground along the water diversion channel between the surface and the stratum,which increases the water content of the clay layer.The cement slurry was injected into the river bottom to form cement soil with the original clay body.In this way,the soil performance was improved and the seepage control was achieved to reduce the instability problem caused by the influence of water in the clay.

关 键 词：综合物探 黏土 含水率 电阻率 

分 类 号：TU43[建筑科学—岩土工程]