坑道瞬变电磁全程数据分析及1∶1含水模型试验研究

All-time data analysis of transient electromagnetic method for tunnels and investigation on 1∶1 water model

考虑到接收系统过渡过程及电流关断时间,通过对接收系统冲激响应函数、一次电动势及二次全程感应电动势理论公式的推导,还原了接收瞬变电磁全程响应信号,与理论全程数据的对比分析表明,电流关断时间和接收系统过渡过程给早、中延时段瞬变场造成严重的畸变,导致数据解析不能有效识别坑道前方近距离地电信息。为评价畸变段数据对坑道超前探水的影响,建立坑道前方1∶1定量水仓模型,通过在掘进工作面连续观测100 m3以内水量变化情况下的瞬变场响应数据,分析并获得了含水模型的瞬变异常响应特征,确定其响应时窗处于畸变数据段,进一步指出现有坑道超前探水技术仍需不断改进,以提高超前预测精度。

Considering the transition of receiving system and the turn-off time of currents, the expressions for impulse response function, primary electromotive force and secondary all-time induced electromotive force are derived. On this basis, the all-time response signals received by receiving coil are restored. The comparative analysis of the receiving and theoretical all-time data shows that the turn-off time of currents and the transition of receiving system distort the early and middle window time data, resulting in undistinguishable electrical information obtained by data processing in short range ahead of tunnels. To assess the impact of aberration data on the advanced water detection in a tunnel, a 1:1 quantitative sump model ahead of the tunnel is established. Through the continuous observation and analysis of the transient field data in different water less than 100 m3, the transient exception response characteristics of water are obtained. It is shown that the response time of the water model is within the time range of the aberration data, and it is further indicated that the technology of advanced water detection must be improved to increase the advanced forecast accuracy.