隧道三维电阻率E-SCAN超前探测反演与优化方法研究

发布时间：2018-04-14 04:29

本文选题：隧道超前预报 + 三维电阻率反演　；参考：《岩土工程学报》2017年02期

【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。
[Abstract]:The advanced geological prediction is an essential link in the tunnel construction. The E-SCAN observation model of surface resistivity is introduced into the tunnel advance prediction, in which both the power supply and the collecting electrode are arranged on the tunnel face.The influence of side interference factors can be reduced effectively. A new observation mode of tunnel advance detection based on 3D resistivity E-SCAN is proposed.In this paper, a geoelectric model of 3D resistivity E-SCAN for tunnel detection is established, and the distribution characteristics of sensitivity matrix are obtained: the value of matrix element is small and the difference is great, the absolute value of element decays rapidly with depth;The absolute value of the elements near the power supply and collecting electrodes is higher.In order to improve the depth localization problem of inversion, different gain factors are applied to the elements in the sensitivity matrix, the high value elements in the original sensitivity matrix are suppressed, and the low value elements are gained.Based on the sensitivity gain factor, an optimization method of tunnel 3D resistivity E-SCAN advanced detection inversion is developed, which can improve the depth localization accuracy of anomalous bodies theoretically.Numerical examples and physical model experiments are carried out. The results show that the inversion optimization method is superior to the conventional smooth constrained inversion method in depth location accuracy of anomalous bodies in tunnel 3D resistivity E-SCAN advanced detection.
【作者单位】：山东大学岩土与结构工程研究中心;
【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)
【分类号】：U452.1;P631.322

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