Experimental study on the detection of karst pores by cross-hole CT imaging and groundwater occurrence in the Luxi karst fault-depression basin
-
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。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.
-
Key words:
- karst fault-depression basin /
- Luxi /
- cross-hole CT imaging /
- groundwater occurrence
-
[1] 麦瑞浩.单孔声波测井与跨孔CT成像在岩溶地区地质勘探中的应用[J].中南公路工程,2004,29(2):141-144. [2] 吴华平.电磁波CT探测技术在岩溶勘探中的应用[J].华南地震,2012,32(4):59-66. [3] 叶福光,黎华清,徐远光.电磁波透视法在大龙洞水库查漏中的应用[J].广西地质,1997,10(4):83-85,100. [4] 黎华清,卢呈杰,韦吉益,等.孔间电磁波CT探测揭示水库坝基岩溶形态特征:以广西靖西大龙潭水库帷幕灌浆为例[J].岩土力学,2008,29(S1):607-610. [5] 梁潮,黄鹤尤.孔间电磁波透视及CT扫描在岩溶区地质勘察中的应用[J].水利规划与设计,2010,4:25-27. [6] 黎华清,甘伏平,魏宇,等.利用孔间CT成像对喀斯特岩体结构、电站坝基渗漏与稳定性研究[J].CT理论与应用研究,2012,21(4):635-645. [7] 甘伏平,李金铭,黎华清,等.跨孔电磁波透视法在岩溶探测中的应用[J].物探与化探,2006,30(4):303-307. [8] 黎华清,徐远光,甘伏平,等.孔间电磁波CT法在左江电站火成岩坝基风化结构评价中的应用[J].岩土力学,2010,31(S1):430-434. [9] 邓争荣,熊永红,蔡加兴.钻孔电磁波CT 在岩溶探测中的应用[J].长江工程职业技术学院学报,2004,21(4):32-34. [10] 《钻孔电磁波法》编写组.钻孔电磁波法〔M〕.北京:地质出版社,1982. [11] 杨文采.地球物理反演和地震层析成像[M].北京:地质出版社,1989:153-161. [12] 高星.地震层析成像研究的回顾与展望[J].地球物理学进展,2000,15(4):42-44. [13] 黎华清,甘伏平,魏宇,等.孔间CT成像与岩溶工程基础岩体结构特征研究[A]//.全国射线数字成像与新技术研讨会·论文集[C].2012,255-258. [14] 王宇,张华,张贵,等.喀斯特断陷盆地环境地质分区及功能[J].中国岩溶,2017,36(3):283-295. [15] 云南省地质调查院.云南泸西小江流域岩溶地下水调查与地质环境整治示范报告[R].桂林:中国地质科学院岩溶地质研究所,2006. [16] 王宇,李燕,谭继中,等.断陷盆地岩溶水赋存规律[M].昆明:云南科技出版社,2003. [17] 左新军,刘勇.“CT”技术在岩溶地区桩基中的应用[J].中外公路,2002,22(5):107-109. [18] 欧阳立胜.电磁波CT探测技术在长安初级中学教学楼场地熔岩探测中的应用[J].华北地震科学,2002,30(3):40-44. [19] 罗传华,昌彦君,陶喜林,等. 井间电磁波技术在居民区地下洞穴调查中的应用[J]. 工程地球物理学报,2010,7(1):78-83. [20] 苟天红,陆永坤.孔间电磁波CT测试在岩溶区工程地质勘察中的应用[A]//贵州省岩石力学与工程学会2014 年学术年会论文集[C].2014. [21] 朱亚军,龙昌东,杨道煌.井间电磁波CT 技术在地下孤石探测中的应用[J].工程地球物理学报,2015,12(6):721-725. [22] 郭印,彭涛,李天祺,等.井间电磁波CT技术在建筑基底溶洞探测中的应用[J].工程勘察,2009,37(8):92-95. [23] 李杨.电磁波CT 技术在场地岩溶勘察中的应用[J].福建建筑,2015(6):94-96. [24] 胡富彭,吴茂林,许殿博,等.利用电磁波CT技术进行岩溶区透视成像[J].CT理论与应用研究,2018,27(2): 205-212. [25] 温一波,王赟赟,胡家富,等.跨孔CT法中采集数据精度对成像效果影响[J].云南大学学报(自然科学版),2000(S1):49-53,64.
点击查看大图
计量
- 文章访问数: 1807
- HTML浏览量: 614
- PDF下载量: 218
- 被引次数: 0