摘要
大量实例表明,在煤矿井下直流电阻率三极超前探测虽然被广泛应用于迎头前方地质异常体的探测,但探测效果并不理想。通过简单的全空间低电阻率球状电性体进行解析式三极超前探测正演计算,以及对地面积水体进行三极超前探测,其解释结果与实际相差较远。根据理论分析,迎头前方存在低阻球体时三极超前探测的视电阻率曲线随探测距离增加呈单调下降趋势,仅能表现出低阻体的存在,但不能真实反映出低阻球体的位置。地面积水坑的探测结果表明,受MN电极接地电阻的影响,与积水坑对应位置并没有出现低阻异常。在山西某地,三极超前探测数据与仪器配套的软件处理解释后获得的二处异常,经钻孔验证均为误判,而钻孔揭露的含水采空区在成果图上却无异常迹像。建议在改善MN接地电阻、改变数据采集方式或增强异常数据处理等方面加强研究,以提高三极超前探测有效性。
The massive examples have shown that although the coalmine underground DC resistivity trielectrode advanced prospecting is widely applied in head-on geologic anomalous body detection, but the effect is not idealistic. Through simple whole space low resis- tivity spherical electric body has carried out analytic trielectrode advanced prospecting forward computation, and trielectrode advanced prospecting for surface ponded water body. But the interpreted results are far from practices. Based on theoretical analysis, when head- on low resistivity spheroid is existed, the trielectrode advanced prospecting apparent resistivity curves will present monotonous falling trend along with the increasing of prospecting distance. It can only exhibit the existence of low resistivity body, but cannot reflect its po- sition truly. The prospected result of surface ponded water body has shown that impacted by MN electrode earth resistance, no conduc- tive anomaly presented corresponding to ponded water body situation. In a Shanxi place, two anomalies from the interpretation of pros- pected data after processed by software matched with instrument are all misinterpreted through drilling validation. While the drilling re- vealed water - bearing gob area has no abnormal image on resuh drawings. So, it is suggested that researches should be strengthened through MN earth resistance improving, data acquisition mode changing or abnormal data processing enhancing to improve effective- ness of trielectrode advanced prospecting.
出处
《中国煤炭地质》
2017年第3期72-75,共4页
Coal Geology of China
关键词
直流电法
三极超前探测
低阻地质体
DC electric method
trielectrode advanced prospecting
conductive geologic body
