不同充填介质下的溶洞跨孔电阻率CT探查数值模拟

胡富彭; 欧元超; 付茂如

doi:10.11932/karst20190513

不同充填介质下的溶洞跨孔电阻率CT探查数值模拟

doi: 10.11932/karst20190513

安徽理工大学地球与环境学院，安徽淮南 232000

基金项目: 国家重点研发计划项目（2016YFC0600900）；国家自然科学基金项目（41702177）

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出版历程
- 发布日期: 2019-10-25

Study on numerical simulation of karst cross-hole resistivity CT exploration at cave with different filling media

School of Earth and Environment，Anhui University of Science and Technology，Huainan，Anhui 232000， China

摘要

摘要: 城市地铁修建过程中常常会遇到溶洞等不良地质条件，为更加准确探查地下溶洞的位置和大小，采用有限元法和最小二乘法正反演数值模拟手段，利用孔距、电极距和与钻孔距离三个变量构建了地下溶洞的地电模型，分析并总结了跨孔电阻率CT法对充气、充水和部分充水溶洞的电阻率响应特征及规律。结果表明：部分充水溶洞的水、气分界面明显，低阻区域和高阻区域与溶洞充水、充气部分位置大小一致，且随着溶洞充水量的增加，溶洞低电阻率响应增强，其异常范围向溶洞顶部扩大；跨孔电阻率CT法能够有效识别溶洞充填性状。
- 跨孔电阻率 /
- 溶洞 /
- 电阻率响应 /
- 数值模拟
Abstract: Unfavorable geological conditions such as karst cave often occur in the construction process of city subway and other railways, which seriously affect the construction progress and the staff’s safety. Therefore, in order to guarantee the normal construction, it is necessary to accurately detect the development features such as the location, size and filling properties of underground hidden karst caves. In this paper, the methods of forward and inversion numerical simulation on the basis of both finite element code and least square were used to construct the geo-electric model, by using three variables of underground caves, such as pitch, electrode spacing and relative hole spacing. Meanwhile, it shows the simulation results in a way of combining two-dimensional section with one-dimensional sounding curve, analyzes and summarizes the response characteristics and cross-hole resistivity CT for gas filled, water filled and partially water filled karst caves. The results indicate that the interface between water and gas in some water-filled karst caves is obvious, and the positions of the low-resistivity area and the high-resistivity area are the same as those of the water-filled and gas-filled parts of the karst caves. In addition, with the increase of filling water volume in the karst caves, the low-resistivity response of the karst caves increases, and the range of low-resistivity anomalies expands towards the top of the karst caves. The resistivity response characteristics of karst caves gradually decrease with the increase of electrode spacing and hole spacing, and the response attenuation of the hole spacing from 6 m to 16 m decreases more obviously than that from 16 m to 25 m. The response to electrode distance from 1 m to 2 m decreases less obviously than that from 0.5 m to 1 m. Meanwhile, the response of partially water filled karst caves decreases more obviously than that of single filled karst caves. When the electrode spacing and hole spacing increase to a certain range, the detection method can’t effectively identify complex karst caves and single filled karst caves; In the process that the karst cave model gradually deviates from the central position of the measured section, the response of the abnormal area weakens when it deviates up and down in the depth direction, and increases when it deviates towards left and right in the transverse direction. Various numerical models indicate that, when the ratio of hole spacing to hole depth and electrode spacing is appropriate, the cross-hole resistivity CT method can effectively identify the filling characteristics of the karst caves, and accurately determine the location and size of the karst caves, which provides a theoretical basis for the cross-hole exploration site and the interpretation of results.
- cross-hole resistivity CT /
- karst cave /
- resistivity response /
- numerical modeling

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参考文献(17)

[1]	周文龙, 吴荣新, 肖玉林. 充水溶洞特征的高密度电阻率法反演分析研究［J］. 中国岩溶, 2016, 35(6):699-705.
[2]	欧元超, 胡雄武, 徐宝超，等. 夹角和偏移距对岩溶区高密度电法响应特征的影响试验研究［J］.水利水电技术,2018, 49(6):156-162.
[3]	薛国强, 宋建平, 马宇,等. 用瞬变电磁法探测灰岩溶洞［J］. 地球科学与环境学报,2003, 25(2):50-53.
[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):611-614.
[5]	高阳, 张庆松, 原小帅,等. 地质雷达在岩溶隧道超前预报中的应用［J］. 山东大学学报:工学版, 2009, 39(4):82-86.
[6]	漆立新, 顾汉明, 李宗杰,等. 基于地震波振幅分辨塔河油田溶洞最小高度的理论探讨［J］. 地球物理学进展, 2008, 23(5):1499-1506.
[7]	席超强, 周文龙, 李建宁. 多道瞬态面波法在岩溶注浆质量检测中的应用［J］. 宿州学院学报, 2016, 31(10):123-126.
[8]	白登海, 于晟. 电阻率层析成象理论和方法［J］. 地球物理学进展, 1995, 10(1):56-75.
[9]	李晓芹, 陶裕录. 电阻率层析成像的原理与初步应用［J］. 地震地质, 1998,20(3):234-242.
[10]	王桦, 纪洪广. 跨孔直流电阻率法CT勘探技术研究［J］. 地球物理学进展, 2010,25(5):1833-1840.
[11]	郝锦绮,冯锐.对样品含水结构的电阻率CT研究［J］.地震学报,2000,22(3):305-309.
[12]	李红立, 张华, 汪传斌. 跨孔超高密度电阻率法在花岗岩球状风化体勘探中的试验研究［J］. 工程勘察, 2010, 38(8):88-92.
[13]	张文俊, 李术才, 苏茂鑫,等. 基于井间电阻率成像的城市地铁溶洞探测方法［J］. 山东大学学报(工学版), 2014(3):75-82.
[14]	李术才, 苏茂鑫, 薛翊国,等. 城市地铁跨孔电阻率CT超前地质预报方法研究［J］. 岩石力学与工程学报, 2014, 33(5):913-920.
[15]	李术才, 刘征宇, 刘斌,等. 基于跨孔电阻率CT的地铁盾构区间孤石探测方法及物理模型试验研究［J］. 岩土工程学报,2015,37(3):446-457.
[16]	蒋林城, 肖宏跃, 丁尚见,等. 跨孔电阻率法装置灵敏度分析及分辨率讨论［J］.地球物理学进展, 2018, 33(2): 815-822.
[17]	林炳臣, 毛承英. 跨孔电阻率CT在岩溶专项勘察中的应用［J］. 西部交通科技, 2014,83(6):91-94.