| 岩溶断陷盆地跨孔CT成像探测岩溶孔隙及赋水状态的实验研究 |
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| 引用本文： | 张华,张贵,王宇,方永林,代旭升,王波,何绕生,罗为群,蓝芙宁.岩溶断陷盆地跨孔CT成像探测岩溶孔隙及赋水状态的实验研究[J].中国岩溶,2020,39(5):737-744. |
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| 作者姓名： | 张华 张贵 王宇 方永林 代旭升 王波 何绕生 罗为群 蓝芙宁 |
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| 作者单位： | 1.云南省地质环境监测院 |
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| 基金项目： | 国家重点研发计划项目“断陷盆地地表、地下水资源高效利用与优化调控”（2016YFC0502502）；中国地质调查局项目“南方石漠化重点区综合地质调查与评价”（DD20190502） |
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| 摘 要： | 泸西岩溶断陷盆地西南部既比村一带广泛分布着碳酸盐岩，岩溶极为发育，且极不均匀，地表以溶隙、溶沟为主，溶蚀残丘发育，局部发育溶井，出露有既比村大泉。通过开展1∶1万水文地质调查，在综合分析研究基础上，采用高密度电法剖面快速扫面，结合激电测深确定井位，实施的示范孔SK1、SK2钻孔，两个钻孔相距48 m，再进行跨孔CT成像探测地下岩溶发育及地下水的赋存状态实验研究，结果表明跨孔CT成像结果与实际钻探成果解译相差不大，表明该方法能更好地解译出地下岩溶发育及地下水赋水状态特征。采用常规的物探方法仅能推测竖直方向的地质情况，不利于查清横向连续发育的破碎带和溶洞空间分布。跨孔电磁波CT探测技术与钻探相结合，可以弥补这方面的不足。在碳酸盐岩地层中，根据在地下空间中不同发射角度的电磁波能量衰减值，利用反演算法得出地下介质的吸收系数空间分布，重建钻孔之间剖面的吸收系数二维图像，不同的吸收系数判断岩溶发育情况及地下水富水性。跨孔电磁波CT探测在岩溶断陷盆地探测结果说明，这种方法可行有效，为更好地布置钻孔找水提供了先进的技术。
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| 关 键 词： | 岩溶断陷盆地 泸西 跨孔CT成像 赋水状态 |
Experimental study on the detection of karst pores by cross-hole CT imaging and groundwater occurrence in the Luxi karst fault-depression basin |
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| ZHANG Hu,ZHANG Gui,WANG Yu,FANG Yonglin,DAI Xusheng,WANG Bo,HE Raosheng,LUO Weiqun,LAN Funing.Experimental study on the detection of karst pores by cross-hole CT imaging and groundwater occurrence in the Luxi karst fault-depression basin[J].Carsologica Sinica,2020,39(5):737-744. |
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| Authors: | ZHANG Hu ZHANG Gui WANG Yu FANG Yonglin DAI Xusheng WANG Bo HE Raosheng LUO Weiqun LAN Funing |
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| Institution: | 1.Yunnan Institute of Geological Environmental Monitoring2.Yunnan Geological Survey3.Yunnan Institute of Geological Engineering Survey and Design4.Institute of Karst Geology，CAGS |
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| Abstract: | Around the Jibi village southwest of the Luxi fault-depression basin, carbonate is widely distributed with well developed highly uneven karst. The surface is dominated by dissolution cracks and gullies with numerous mosore and some karst wells, one of which exposes as a big spring at the Jibi village. This work built on an 1∶10,000 hydrogeology survey. Using the high-density electrical method section，rapid scanning，combined with the IP sounding, locations of two boreholes to be drilled were determined,where the demonstration holes SK1 and SK2,48 m apart,were drilled.Then cross-hole CT imaging was conducted to detect the underground karst development and groundwater occurrence state. The results show that the cross-hole CT results are largely consistent with drilling interpretation, permitting to reveal the underground karst and groundwater occurrence. While the conventional geophysical methods can only speculate the geology in vertical direction, not clarifying horizontal fracture zones and karst caves. Combination of cross-hole electromagnetic and drilling can just can make up this deficiency. In carbonate formation,according to attenuation values of electromagnetic wave energy from different emission angles in the underground space,this approach allows to use inversion algorithms to calculate the absorption coefficients of underground media,reconstruct 2D images of the absorption coefficients in profiles between boreholes, and infer the occurrence of karst and groundwater in the subsurface. The detection results of cross-hole electromagnetic CT in the Luxi karst fault-depression basin show that this method is feasible and effective，and provides support for better arrangement of boreholes. |
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