井间超高密度电阻率法溶洞探测研究

Karst cave prospecting using cross-hole ultra-high density resistivity method

利用井间超高密度电阻率法对广州地铁某在建段浅层隐伏岩溶发育情况进行了探测实验。结果表明:利用现有勘察孔进行井间超高密度电阻率法探测溶洞是可行的,通过正反演计算获得的井间电阻率分布特征能直观给出溶洞在横向、纵向上的分布范围,但是对溶洞连通性不易区分,深度偏差为电极距大小。探测时,电法孔孔深一致,孔深和孔间距比大于1.5倍,电极间距1~2 m。

The prospecting of shallowly concealed karst caves is studied using the cross-hole ultra-high density resistivity method.The results are as follows.It was feasible to prospect Karst caves using existing survey boreholes according to the cross-hole ultra-high density resistivity method.The transverse and longitudinal distribution ranges of karst caves can be directed reflected by the distribution characteristics of the cross-hole resistivity obtained through forward and inverse calculations.Meanwhile,it was difficult to distinguish the connectivity between karst caves,and the depth deviation was the distance between two adjacent electrodes.It is suggested that the depth of the boreholes used should be consistent,the ratio of the borehole depth to the borehole space should be higher than 1.5,and the electrode space should be 1~2 m in practice.