马河崩塌堆积体结构特征与稳定性评价.pdf

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1、JournalofEngineeringGeology工程地质学报1004—9665／2011／19(4)一0588-06马河崩塌堆积体结构特征与稳定性评价球李广平①常中华②(①广州市市政工程设计研究院广州510060)(②中国科学院地质与地球物理研究所北京100029)摘要马河崩塌体堆积边坡坡度陡峭，起伏变化大，钻孔勘探难以准确查明边坡松散覆盖层厚度、边坡下伏基岩起伏情况及其风化发育程度。选用地震散射剖面的物探方法探明了马河崩塌堆积体结构特征，并采用多种极限平衡法(Bishop、Janbu、Morgenste

2、rn—Price)计算和对比基覆界面的安全系数，评价马河崩塌堆积体在三种不同工况下(自然工况、地震工况、降雨工况)的稳定性。得出结论为：马河崩塌堆积体的地质结构可分为三层：靠近地表为厚度为30-40m左右的松散覆盖层，未胶结；中间为厚度10～15m的中一强风化层，节理裂隙发育；40～50m以下为完整性较好的基岩，波速在2500m·s以上。对地震和降雨2种不利工况进行了稳定性评价：在地震工况下，崩塌体可沿着覆盖层底界面或者风化层底界面发生失稳破坏；在降雨工况下，崩塌体可沿着风化层底界面发生失稳破坏。关键词崩塌体结

3、构特征稳定性中图分类号：P642．21文献标识码：ATHESTRUCTURALCHARACTERISTICANDTHESTABILITYANALYSISoFMAHECoLLAPSEBoDYLIGuangpingCHANGZhonghua((j~GuangzhouMunicipalEngineeringDesign&ResearchInstitute，Guangzhou510060)((~lnstituteofGeologyandGeophysics，ChineseAcademyofSciences，Beijin

4、g100029)AbstractThispapermainlyresearchesthestructuralcharacteristicandthestabilityanalysisofMahecollapsebody．Firstofall，therangeofslopeandchangingshapeinlandscapeorientationrestrainttheapplicationofdrillingexploration．Itisdificulttofigureouttheloosecoverage

5、thickness，fluctuatingbedrockbeneathandsituationofde—velopingweatheredlayerexactly．Hence，thispaperadoptsSSP(SeismicScatterProfile)methodtoexplorethestruc—turalcharacteristicofMahecollapsebody．Furthermore，thispaperevaluatesthestabilityofMahecollapsebodyun—dert

6、hreeconditions(naturalcondition、ea~hquakeconditionandrainfallcondition)byusingvariousLEM(Bishop、Janbu、Morgenstern-Price)andthencalculatingandcomparingthesafetyfactorsofdiscontinuitybetweenbedrockandcoverage．Finally，thispaperconcludesthatthegeologicalstructur

7、eofMahecollapsebodyisapproximatelysor—tedintothreelayers．Theupperlayerclosetosurfaceisloosecoveragewithathicknessabout30～40mm，notee-mentitious；Themediumlayerisamediumtostrongweatheredlayerwithathicknessabout10～15ram，weatheredstrongly，fracturedintensively；The

8、bottomlayerisarelativelyintactrockmassunder40～50mdepthwithawavevelocityabove2500m·s～；Astostabilityevaluation，therearetwounstableconditions：thecollapsebodymayoccur}收稿13期：2011—04—10；收到修改稿日期：2011—0