坑道掘进瞬变电磁超前探水技术应用分析

坑道掘进前方含水体一直是影响安全生产的主要因素之一，瞬变电磁法在超前探水预报中发挥了重要作用。由于坑道全空间探测条件的特殊性，其测试布置方式对探测结果判断产生一定影响，主要表现在干扰因素剔除、电阻率深度计算、异常体空间判断等内容。为了获得较为可靠的探测结果，通过改进测试布置方式，增加中心线方向竖直测试剖面，与坑道迎头顶板、顺层、底板剖面一起形成四断面法超前测试，增强了对前方含水异常体的空间判断能力。通过与瞬变电磁超前常规探测方式相对比，认为四断面法利用横断面与纵剖面相结合，对地质体判断的优越性较强。现场应用结果表明，该方法在预报测区前方地质异常体时，以低于10 ?•m为低阻异常区判断标准，具有一定的可靠性，能为坑道掘进安全生产提供有效指导。

Applied analysis of advanced detection for containing water body ahead of tunnel by transient electromagnetic method

The containing water body is one of the primary factors to impact the safety in production all the time. The transient electromagnetic method plays an important role on the advanced detection of water disaster in tunnel. Because of the detecting particularity in full space condition of tunnel, the detecting and forecasting results are often affected by the layout way of detection, and it often expresses in serial fields such as the interference factor rejection, depth calculation of resistivity, space judgment for abnormality, and so on. For acquiring more reliable detecting results, the testing arrangement is improved in the article. The detecting section in the direction of centre line is added, and it forms the detection method of four-section ahead of tunnel with the roof section, along tunnel section, and bottom floor section. The judging ability of space for the containing water body ahead of tunnel is enhanced. Through contrasting the results of the convention detecting pattern, the advantage of four-section method for geology body judgment is analyzed because of its combining cross-section and longitudinal section. The detecting practices show that it is reliable to use under 10 ?•m as the criteria of the resistivity to forecast the low resistivity field in the tunnel along the 6 coal seams for the advanced detection by the four-section transient electromagnetic method. It has important instructing value for driving safety of tunnel.