巷道激电三维超前探测技术正演研究

摘要

Aiming at the key technology of tunnel advance detection,fast forward modeling on 3D complex conditions of tunnels was realized by 3D finite element numerical simulation technique.Based on 3D fast forward modeling and program,this paper analysed and calculated the influence laws of tunnel itself and lateral abnormal bodies on induced polarization (IP) detection of tunnel floor.The least squares fitting formula was applied to deduce the approximate correcting formula which could correct the the inference of super high resistivity of the tunnel itself.Results of research showed that the approximate correcting formula had a good fitting effect on the influences of tunnel itself,the fitting error was less thau 3％,and could be used for actual tunnel influence correction.For tunnel front advanced detection,compared to the abnormal of resistivity,apparent polarization abnormal gained by three electrode method has better effects of advanced detection,for advanced detection of tunnel floor and side wall,three electrode method is usually applied to reflect geo-electric information on the outer direction of the line surface.%针对超前探测技术是巷道掘进的关键技术问题,利用三维有限元数值模拟技术实现了巷道三维复杂条件下激电观测异常场的快速正演.在三维正演基础上,分析计算了巷道本身、巷道掘进工作面及旁侧异常体等对巷道底板激电探测的影响规律,利用最小二乘拟合法导出了校正巷道空腔影响的近似公式.研究结果表明:近似校正公式能较好地拟合巷道本身的影响,校正结果与正演模拟结果拟合误差小于3％,可用于实测数据的巷道影响校正;对于巷道掘进超前探测,与电阻率异常相比,三极法探测的视极化率异常具更好的超前探测效果;对于底板和侧帮的探测,三极法探测主要反映测线所在面外侧的地电信息.