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巷道空间对全空间瞬变电磁场的影响特征是矿井瞬变电磁法中尚未妥善解决的理论问题.从电磁场满足的麦克斯韦方程组和边界条件出发,推导洛伦兹规范和库伦规范下位函数满足的控制方程和边界条件,作为含三维巷道全空间水平层状介质模型的边值问题.用边界元法模拟了含巷道的典型3层地电模型的瞬变电磁响应特征,分析了有无巷道时视电阻率的变化规律及模型参数的变化对巷道响应特征的影响规律,提出了改变巷道所在层参数时巷道影响变化最大,即巷道围岩介质导电性是决定巷道影响大小的最直接因素的观点.结果表明:巷道空间的存在使得视电阻率值发生显著变化,与无巷道时相比其值变大,巷道影响大小介于1.0~2.5之间;当发射源放置在巷道底板上时,底板岩层的电阻率越小,巷道影响变化越大,顶板岩层电阻率所引起的巷道影响变化最小.研究结果为进一步建立巷道影响校正算法提供了理论依据.
The influence of roadway space on the full space transient electromagnetic field is a theoretical problem that has not been properly solved in the mine transient electromagnetic method.From the Maxwell’s equations and the boundary conditions that the electromagnetic field satisfies, the Lorentzian criterion and the control of the subordinate function of the Coulomb criterion Equations and boundary conditions as the boundary value problem for layered media model with 3D spatial model in the full space of the roadway.The transient electromagnetic response characteristics of typical 3-layer geoelectric model with laneway are simulated by the boundary element method The change law of resistivity and the influence of the change of model parameters on the response characteristics of the roadway. It is proposed that the change of the roadway influence is the greatest when the parameters of the roadway are changed. That is, the conductivity of the surrounding rock of the roadway is the most direct factor that determines the influence of the roadway. The results show that the existence of the tunnel space makes the apparent resistivity value change significantly, which is larger than that in the case of no roadway, and the influence of the roadway is between 1.0 and 2.5. When the emitter is placed on the roadway floor, The smaller the resistivity, the greater the impact of roadway changes, the change of roadway influence caused by the resistivity of roof rock formation is the least. Step establish Roadway correction algorithm provides a theoretical basis.