隧道三维电阻率E-SCAN超前探测反演与优化方法研究  

3D E-SCAN resistivity inversion and optimized method in tunnel advanced prediction

作　　者：王传武[1] 李术才[1] 聂利超[1] 刘斌[1] 郭谦[1] 任玉晓[1] 刘海东[1] WANG Chuan-wu LI Shu-cai NIE Li-chao LIU Bin GUO Qian REN Yu-xiao LIU Hai-dong(Research Center of Geotechnical ＆ Structural Engineering, Shandong University, Jinan 250061, China)

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061

出　　处：《岩土工程学报》2017年第2期218-227,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家重点基础研究发展计划("973"计划)项目(2013CB036002;2015CB058101);国家重大仪器设备研制专项(51327802);国家自然科学基金重点项目(51139004);国家自然科学基金面上项目(51479104);国家自然科学基金青年科学基金项目(41502279);中国博士后科学基金项目(2015M572037);国家重点研发计划(2016YFC0401805)

摘　　要：超前地质预报是隧道施工中必不可少的环节,将地面三维电阻率E-SCAN观测模式引入到隧道超前预报中,其中供电与采集电极都布置在隧道掌子面,可有效降低旁侧干扰因素的影响,提出了基于三维电阻率E-SCAN的隧道超前探测新型观测模式。建立了隧道三维电阻率E-SCAN超前探测地电模型,获得了敏感度矩阵分布特征:矩阵元素数值较小且相差悬殊;元素绝对值随深度衰减迅速;靠近供电与采集电极位置元素绝对值较高。为改善反演的深度定位问题,对敏感度矩阵中元素施加不同大小的增益因子,对原有敏感度矩阵中高值元素进行抑制,对低值元素进行增益,形成了基于敏感度增益因子的隧道三维电阻率E-SCAN超前探测反演优化方法,在理论上可以提高异常体的深度定位精度。开展数值算例与物理模型试验研究,结果表明在隧道三维电阻率E-SCAN超前探测中,相较于常规光滑约束反演,反演优化方法在异常体的深度定位精度方面具有明显优势。Advanced geological prediction is one essential part in tunnel construction, and 3D E-SCAN resistivity device is introduced. In this device, the current and measuring electrodes are arranged on the tunnel face, which can reduce the impact of interference factors. Then a new observing device is proposed. Geological models are designed, and features of the sensitivity matrix are obtained as follows： the absolute values of elements are vastly different; the values decrease sharply with depth; the elements close to the current and measuring electrodes achieve high absolute values. The gain factors with different values are imposed onto the elements in the sensitivity matrix, and the initial elements with high values are suppressed, with the elements with low values enhanced. An optimized inverse method is formed based on the gain factors, and it can promote the depth accuracy of the abnormal in inverse results theoretically. Numerical examples and physical model tests are performed. The results show that in the 3D E-SCAN resistivity detection, compared with the traditional smooth constraints inversion, the optimized inverse method has obvious advantages in positioning the abnormal body in depth.

关 键 词：隧道超前预报 三维电阻率反演 E-SCAN 敏感度矩阵 光滑约束权重 增益优化 

分 类 号：TU43[建筑科学—岩土工程]