双线高密度电阻率法分析断层产状的原理和算法
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摘要
断层产状计算是工程勘探中一个重要内容,一般利用地质罗盘和皮尺测量断层露头的方法进行计算,其运用范围受到了极大限制。利用高密度电法勘探可得到沿测线走向剖面上地下构造的电阻率剖面,结合已知的地层信息可以判断断层的存在和规模,但无法准确确定其产状。文中提出采用双线电法勘探的方法分析并准确计算断层产状,包括倾向、倾角和宽度指标。该方法假设断层同时切割两条测线,且在测线间断层结构面无较大褶曲,可简化为平面。计算过程中,首先根据单线电阻率剖面判断断层的范围和边界,采用最小二乘法确定其切割面参数,然后根据断层在两个剖面上的投影反算断层的倾向、倾角,最后根据断层和电阻率剖面的空间交互关系反推断层宽度。文中详细介绍了该方法的理论基础和推导过程,并对其运用条件进行了阐述。文中对该方法在厦门市某隧道勘探中断层产状计算成果进行了归纳、统计和分析,并选择断层出露地面位置的计算结果与采用传统地质罗盘测量结果进行了对比分析。结果表明根据文中计算分析方法得出的断层产状和宽度与实际测量结果相比有一定误差,倾向相差3°~5°,倾角相差2°~6°,宽度相差11%~16%,主要是因为断层延伸过程中受地质构造作用而发生几何性状变化引起的,但是在较小的勘探区域内仍然能够较为准确地反映实际情况。
Fault occurrence calculation is an important content in engineering exploration,generally,geological compass and tape are used to measure these parameters,and its application is greatly restricted.By using high-density electrical method combining with known information of stratum provided,the resistivity profile of the underground structure along the measuring line can be got,with which the existence and scale of the fault can be judged,but its occurrence cannot be gotten precisely.It is proposed to use the double-line high-density resistivity method to solve the problem,that is calculating the parameter including dip direction angle,dip angle and width of the fault.It is assumed that the fault cut the 2 survey lines at same time and there exists no strong fold between 2 lines.At first,it judges border and range of the fault on the resistivity profile and calculates the parameters of the cutting area with least square method.Then,it back calculates the dip direction angle,dip angle of the fault according to its projections on the 2 profiles.Finally,it inverses the fault's width according to the spatial interaction between fault and resistivity profile.The theoretical basis and the derivation process of the method are introduced in detail,and its application conditions are expounded.The method is used in a tunnel exploration project in Xiamen,and the fault occurrence calculation results are summarized,counted and analyzed,the calculating result of the selected exposed faultexplored by geological compass is compared with the data derived by the proposed method.The result shows that there are some error between the two methods,the dip direction angle error between 3°-5°,dip angle error between 2°-6°,and width error between 11%-16%,mainly because of the faults' geometry changes for the geological tectonism during fault extension,but it still be able to accurately reflect the actual situation in a small exploration area.
Fault occurrence calculation is an important content in engineering exploration,generally,geological compass and tape are used to measure these parameters,and its application is greatly restricted.By using high-density electrical method combining with known information of stratum provided,the resistivity profile of the underground structure along the measuring line can be got,with which the existence and scale of the fault can be judged,but its occurrence cannot be gotten precisely.It is proposed to use the double-line high-density resistivity method to solve the problem,that is calculating the parameter including dip direction angle,dip angle and width of the fault.It is assumed that the fault cut the 2 survey lines at same time and there exists no strong fold between 2 lines.At first,it judges border and range of the fault on the resistivity profile and calculates the parameters of the cutting area with least square method.Then,it back calculates the dip direction angle,dip angle of the fault according to its projections on the 2 profiles.Finally,it inverses the fault's width according to the spatial interaction between fault and resistivity profile.The theoretical basis and the derivation process of the method are introduced in detail,and its application conditions are expounded.The method is used in a tunnel exploration project in Xiamen,and the fault occurrence calculation results are summarized,counted and analyzed,the calculating result of the selected exposed faultexplored by geological compass is compared with the data derived by the proposed method.The result shows that there are some error between the two methods,the dip direction angle error between 3°-5°,dip angle error between 2°-6°,and width error between 11%-16%,mainly because of the faults' geometry changes for the geological tectonism during fault extension,but it still be able to accurately reflect the actual situation in a small exploration area.
引文
[1]王兴泰,傅春久,程德福.高密度电阻率法[M].北京:地质出版社,1996.WANG Xing-tai,FU Chun-jiu,CHENG De-fu.Highdensity Resistivity Method[M].Beijing:Geological Press,1996.
[2]潘别桐,黄润秋.工程地质数值法[M].北京:地质出版社,1994.PAN Bie-tong,HUANG Run-qiu.Numerical Method of Engineering Geology[M].Beijing:Geo-logical Press,1994.
[3]杨金山,张立忱,欧阳兆国.高密度电法在近场区断层探测中的应用[J].东北地震研究,2007,23(7):47-51.YANG Jin-shan,ZHANG Li-chen,OUYANG Zhao-guo.Application of the High-density Electrical Method in the Adjacent Field Section Survey[J].Seismological Research of Northeast China,2007,23(7):47-51.
[4]阿发友,周洪庆,杜定全.高密度电法在乌当断层探测中的应用[J].勘察科学技术,2008(2):58-60.A Fa-you,ZHOU Hong-qing,DU Ding-quan.Application of High Density Resistivity Method to Survey Wudang Fault[J].Site Investigation Science and Technology,2008(2):58-60.
[5]于青春,薛果夫,陈德基.裂隙岩体一般块体理论[M].北京:中国水利水电出版社,2007.YU Qing-chun,XUE Guo-fu,CHEN De-ji.General Block Theory of Fractured Rock Mass[M].Beijing:China Water Power Press,2007.
[6]WU T H,KRAFT L M.Safety Analysis of Slopes[J].Journal of Soil Mechanics and Foundation Division,1970,96(2):609-630.
[7]LONSO E E.Risk Analysis of Slopes and Its Application to Slopes in Canadian Sensitive Clays[J].Geotechnique,1976,26(3):453-472.
[8]CHRISTIAN J T,LADD C C,BAECHER G B.Reliability Applied to Slope Stability Analy-sis[J].Journal of Geotechnical Engineering,1994,120(12):2181-2207.
[9]张赓,庹先国,汪楷洋.高密度电法-氡气测量在矿区隐伏断层勘查中的应用[J].金属矿山,2013(8):74-76.ZHANG Geng,TUO Xian-guo,WANG Kai-yang.Application of High Density Resistivity Method and Radon Survey in the Diggings of Blind Fault Survey[J].Metal Mine,2013(8):74-76.
[10]周玉新,周志芳,孙其国.岩体结构面产状的综合模糊聚类分析[J].岩石力学与工程学报,2005,24(13):2283-2287.ZHOU Yu-xin,ZHOU Zhi-fang,SUN Qi-guo.Synthetical Fuzzy Clustering Analysis for Joints Occurrence of Rock Mass[J].Chinese Journal Rock Mechanics and Engineer-ing,2005,24(13):2283-2287.
[11]姜早峰.高密度电法CT成像技术在活断层探测中的应用[J].东北地震研究,2004,20(2):40-43.JIANG Zao-feng.Application of Complex Resistivity CT Tomography Technology in Active Fault Survey[J].Seismological Research of Northeast China,2004,20(2):40-43.
[12]杨文军,洪宝宁,孙少锐.基于块体理论进行隧道轴线走向优化的研究[J].公路交通科技,2010,27(7):88-93.YANG Wen-jun,HONG Bao-ning,SUN Shao-rui.Research on Optimization for Axis Trend of Rock Tunnel Based on Block Theory[J].Journal of Highway and Transportation Research and Development,2010,27(7):88-93.
[13]陈梦,冯少孔,车爱兰,等.面波勘探和台阵地脉动观测相结合的地基调查法及其在松江古照壁保护中的应用[J].上海交通大学学报,2013,47(10):1557-1561.CHEN Meng,FENG Shao-kong,CHE Ai-lan,et al.Application of Geo-Investigation to Songjiang Ancient Wall Based on Surface Wave Survey and Array Microtremor Observation[J].Journal of Shanghai Jiaotong University,2013,47(10):1557-1561.
[14]文丽娜,白志勇,汪洋.昔格达地层路堑边坡稳定性物元分析[J].公路交通科技,2006,23(8):48-52.WEN Li-na,BAI Zhi-yong,WANG Yang.Matter Element Analysis of the Stability of Cut Slope in Xigeda Strata Area[J].Journal of Highway and Transportation Research and Development,2006,23(8):48-52.
[15]葛如冰.高密度电阻率法在广东省工程勘察中的应用实例[J].物探与化探,1997,21(5):377-381.GE Ru-bing.Examples of Applying High-density Electrical Resistivity to Engineering Exploration in Guangdong Province[J].Geophysical and Geochemical Exploration,1997,21(5):377-381.
[16]LOKE M H,BARKER R D,LOKE M H,et al.Rapid Least-squares Inversion of Apparent Resistivity Pseudosections by a Quasi-Newton Method[J].Geophysical Prospecting,1996,44(1):131-152.
[17]LOKE M H,BARKER R D.Practical Techniques for 3D Resistivity Surveys and Data Inver-sion[J].Geophysical Prospecting,1996,44(3):499-523.
[18]李瑞有,甘孝清,周武.基于均匀设计及遗传神经网络的大坝力学参数反分析方法[J].岩土工程学报,2007,29(1):125-130.LI Rui-you,GAN Xiao-qing,ZHOU Wu.Back Analysis on Mechanical Parameters of Dams Based on Uniform Design and Genetic Neural Network[J].Chinese Journal of Geotechnical Engineering,2007,29(1):125-130.
[2]潘别桐,黄润秋.工程地质数值法[M].北京:地质出版社,1994.PAN Bie-tong,HUANG Run-qiu.Numerical Method of Engineering Geology[M].Beijing:Geo-logical Press,1994.
[3]杨金山,张立忱,欧阳兆国.高密度电法在近场区断层探测中的应用[J].东北地震研究,2007,23(7):47-51.YANG Jin-shan,ZHANG Li-chen,OUYANG Zhao-guo.Application of the High-density Electrical Method in the Adjacent Field Section Survey[J].Seismological Research of Northeast China,2007,23(7):47-51.
[4]阿发友,周洪庆,杜定全.高密度电法在乌当断层探测中的应用[J].勘察科学技术,2008(2):58-60.A Fa-you,ZHOU Hong-qing,DU Ding-quan.Application of High Density Resistivity Method to Survey Wudang Fault[J].Site Investigation Science and Technology,2008(2):58-60.
[5]于青春,薛果夫,陈德基.裂隙岩体一般块体理论[M].北京:中国水利水电出版社,2007.YU Qing-chun,XUE Guo-fu,CHEN De-ji.General Block Theory of Fractured Rock Mass[M].Beijing:China Water Power Press,2007.
[6]WU T H,KRAFT L M.Safety Analysis of Slopes[J].Journal of Soil Mechanics and Foundation Division,1970,96(2):609-630.
[7]LONSO E E.Risk Analysis of Slopes and Its Application to Slopes in Canadian Sensitive Clays[J].Geotechnique,1976,26(3):453-472.
[8]CHRISTIAN J T,LADD C C,BAECHER G B.Reliability Applied to Slope Stability Analy-sis[J].Journal of Geotechnical Engineering,1994,120(12):2181-2207.
[9]张赓,庹先国,汪楷洋.高密度电法-氡气测量在矿区隐伏断层勘查中的应用[J].金属矿山,2013(8):74-76.ZHANG Geng,TUO Xian-guo,WANG Kai-yang.Application of High Density Resistivity Method and Radon Survey in the Diggings of Blind Fault Survey[J].Metal Mine,2013(8):74-76.
[10]周玉新,周志芳,孙其国.岩体结构面产状的综合模糊聚类分析[J].岩石力学与工程学报,2005,24(13):2283-2287.ZHOU Yu-xin,ZHOU Zhi-fang,SUN Qi-guo.Synthetical Fuzzy Clustering Analysis for Joints Occurrence of Rock Mass[J].Chinese Journal Rock Mechanics and Engineer-ing,2005,24(13):2283-2287.
[11]姜早峰.高密度电法CT成像技术在活断层探测中的应用[J].东北地震研究,2004,20(2):40-43.JIANG Zao-feng.Application of Complex Resistivity CT Tomography Technology in Active Fault Survey[J].Seismological Research of Northeast China,2004,20(2):40-43.
[12]杨文军,洪宝宁,孙少锐.基于块体理论进行隧道轴线走向优化的研究[J].公路交通科技,2010,27(7):88-93.YANG Wen-jun,HONG Bao-ning,SUN Shao-rui.Research on Optimization for Axis Trend of Rock Tunnel Based on Block Theory[J].Journal of Highway and Transportation Research and Development,2010,27(7):88-93.
[13]陈梦,冯少孔,车爱兰,等.面波勘探和台阵地脉动观测相结合的地基调查法及其在松江古照壁保护中的应用[J].上海交通大学学报,2013,47(10):1557-1561.CHEN Meng,FENG Shao-kong,CHE Ai-lan,et al.Application of Geo-Investigation to Songjiang Ancient Wall Based on Surface Wave Survey and Array Microtremor Observation[J].Journal of Shanghai Jiaotong University,2013,47(10):1557-1561.
[14]文丽娜,白志勇,汪洋.昔格达地层路堑边坡稳定性物元分析[J].公路交通科技,2006,23(8):48-52.WEN Li-na,BAI Zhi-yong,WANG Yang.Matter Element Analysis of the Stability of Cut Slope in Xigeda Strata Area[J].Journal of Highway and Transportation Research and Development,2006,23(8):48-52.
[15]葛如冰.高密度电阻率法在广东省工程勘察中的应用实例[J].物探与化探,1997,21(5):377-381.GE Ru-bing.Examples of Applying High-density Electrical Resistivity to Engineering Exploration in Guangdong Province[J].Geophysical and Geochemical Exploration,1997,21(5):377-381.
[16]LOKE M H,BARKER R D,LOKE M H,et al.Rapid Least-squares Inversion of Apparent Resistivity Pseudosections by a Quasi-Newton Method[J].Geophysical Prospecting,1996,44(1):131-152.
[17]LOKE M H,BARKER R D.Practical Techniques for 3D Resistivity Surveys and Data Inver-sion[J].Geophysical Prospecting,1996,44(3):499-523.
[18]李瑞有,甘孝清,周武.基于均匀设计及遗传神经网络的大坝力学参数反分析方法[J].岩土工程学报,2007,29(1):125-130.LI Rui-you,GAN Xiao-qing,ZHOU Wu.Back Analysis on Mechanical Parameters of Dams Based on Uniform Design and Genetic Neural Network[J].Chinese Journal of Geotechnical Engineering,2007,29(1):125-130.