电法在堤坝、深埋长隧道、突水灾害等工程勘察中的应用(底青云)

电法在堤坝、深埋长隧道、突水灾害等工程勘察中的应用底青云、王若、王光杰等中国科学院地质与地球物理研究所2008年11月1日报告内容：----高密度电阻率成像系统（RT)----CSAMT反演和勘察应用1.高密度电阻率成像(ResistivityTomography,RT)Depth:0~200mFig.1Thearrangementofelectrodesfora2-Delectricalsurveyandthesequenceofmeasurementsusedtobuildupapseudo-sectionElectrodeNumberC1P2P1C2Station1ResistivityMeterLaptopComputerC1P1P2C22a2a2aStation181220345678910111213141918171615aaa.........................................................11832435156DataLeveln=1n=2n=3n=4n=5n=6C1P1P2C23a3a3aStation32RTwithZhodymethodFig.2Singlehighresistivitybody(a)Model;(b)RTresult10(,)(,)(,)(,)iicilnlnlnlnZhodymethodisonekindofiterationinversionprocedure,Theiterationequationis:510152025-10-550200201(a)点距（米）深度（米）510152025-10-530120150200250(b)点距（米）深度（米）Distance/mDistance/mDepth/mDepth/mρ/Ωmρ/Ωm(b)102030405060708090100HorizontalDistance(m)70605040302010Depth(m)-0.050.000.050.100.150.200.250.300.350.400.450.50(a)102030405060708090100HorizontalDistance(m)70605040302010Depth(m)-0.050.000.050.100.150.200.250.300.350.400.450.50Fig.3ThefaultmodelandRTsections(a)Model;(b)RTsection.Theinversionresulthasaverygoodmatchtothemodel.RTwithIntegralmethod13310()42jjjjkjjjkjjjUUUAUUrAAUThesensitiveequationofpotentialchangingwithmediaresistivityis:Theinversionequationis:45ResultinDa-yeofShanDongofChinaThepurposefordamRTexplorationistofindthewaterleakingposition135014001450150015501600(c)135014001450150015501600135014001450150015501600(d)135014001450150015501600100150200250300350400450500550600(a)100150200250300350400450500550600100150200250300350400450500550600(b)1001502002503003504004505005506000100200300350400500550600700800900110012001300170150130170150130168148128168148128ABCCCCAAABBCCBBB海拔（m）海拔（m）海拔（m）桩号（距离：m）桩号（距离：m）桩号（距离：m）山东沂水跋山水库大坝电阻率CT解释剖面(a)西段，海拔约180m(b)西段，海拔约178m(c)东段，海拔约180m(d)东段，海拔约178m桩号（距离：m）A------坝体B------弱风化带C------基岩Station/mSealevel/mSealevel/mSealevel/mStation/mStation/mρ/ΩmA:Dambody,B:weatheredlayer,C:baserockFig.6FourresistivityimagingsectionsforBa-shandamFigure(a)and(b)arethetwoparallelprofileswiththespace20matthesamepositionofthedam;Figure(c)and(d)aretheothertwoparallelprofileswiththespace20matanotherpositionofthedam.ThepositionoftheancientriverBa-shanDam2.CSAMT数据反演及工程勘察(ControlSourceAudio-FrequencyMagnetotelluric,CSAMT)Depth:0~1500m•Frequency:0.25Hz~10kHz•Depth:0~1500m•Power:30kw2.1CSAMTworkingconfigurationandparametersABR△Tx△△△△△△Rx△△△△△△NMFig.8CSAMT工作示意图2.2SomeCSAMTresearchworkCSAMT勘察中突出的问题是：•近场问题•静态问题•地形问题ThewholefrequencydomainresistivitycorrectionK3layersmedia1212100,500,3100100,500,2000,17.5mmmhmhmrmBeforecorrectionAftercorrectionMTCurveHK4layersmedia23400,500,2000,17.5hmhmrm12100,2,mm341100,2,100mmhmNearfieldcorrectionMTCurveBeforecorrectionAftercorrectionFig.9CSAMT近场校正•Filtermethod•EMAPmethod•Curvesshiftmethod•2.5DFEMinversion02004006008001000-1400-1200-1000-800-600-400-200002040608010012014016018020022024026028030032034036038040042044046048002004006008001000-1400-1200-1000-800-600-400-200002040608010012014016018020022024026028030032034036038040042044046048002004006008001000-1400-1200-1000-800-600-400-2000020406080100120140160180200220240260280300320340360380400420440460480(a)(b)(c)(d)(e)静态引起的条带异常02004006008001000-1400-1200-1000-800-600-400-2000020406080100120140160180200220240260280300320340360380400420440460480StaticcorrectionConclude：Thecorrectioneffectwithcurveshiftmethodand2.5DFEMisbetter.1Dinversionbeforecorrection1DinversionafterEMAPcorrection1Dinversionwithcurveshiftcorrection,frequency256-1024Hz1Dinversionwithcurveshiftcorrection,frequency32-128Hz2.5DFEMinversionFig.10CSAMT静态校正Developed1Dstrip-layermethod,2DRRIand2.5DFEMinversionmethods60657075808590-60-55-50-45-40-35-303050709011060657075808590-60-55-50-45-40-35-301001010mmm(m)2DinversionprofileTwoconductivitybodiesmodel2.5DinversionprofileTwoconductivitybodiescoveredby2thinlayersDatainversionFig.11CSAMT反演2.3CSAMT工程勘察实例•深埋长隧道•矿突水灾害勘察•地质构造勘察CSAMT南水北调隧道勘察12图13南水北调西线一期工程阿克河以东20km工程质剖面：西剖面东剖面图14CSAMT反演及推断解释剖面：低阻异常区目的是发现可能造成隧道施工隐患的断层、破碎带及含水异常带。钻孔04-ZD-1018处的岩芯图片。岩性为泥质充填物和角砾混合物CSAMT太行山隧道勘察Fig.15CSAMT太行山隧道-1000100200300500600700800900100011001200tunnelpositionSN100140180220260300340380420460500540DangerareaFig.16CSAMTresistivityinversionprofileforDK88+880m-200-100010020030040050060050060070080090010001100120013005006007008009001000110012001300tunnelpositionSN100140180220260300340380420460500540DangerareaFig.17CSAMTresistivityinversionprofileforDK88+750mCSAMT牡丹江隧道勘察图18CSAMT法煤田突水隐患勘察20100180260340420500580660740820900980106011401220130013801460154016201700Station/m20100180260340420500580660740820900980106011401220130013801460154016201700Fig.11ResistivityProfileforTangShanLineD023withCSAMT-1500-1400-1300-1200-1100-1000-900-800-700-600-500-400-300-200-1000Depth/m-1500-1400-1300-1200-1100-1000-900-800-700-600-500-400-300-200-1000-20001030506080100150200300400500700900120015001510152025303540444379983.043(X)470160.953(Y)4381626.602(X)470668.973(Y)Stake/NO.Station/mF20Q--Quartery5--coallayer512--1