贵州省水麻坨滑坡的复杂运动破坏机制探讨
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摘要
思南县水麻坨堆积层斜坡受多期强降雨影响,从2011年初开始相继出现地表开裂、墙体倾斜、地坪及墙体裂缝变形加剧等地质灾害现象,危及大同社区93户509人、房屋556间,给当地社会稳定带来了极大的负面影响。一旦继续遭受强降雨等不利因素的影响,滑坡可能会变形滑动。基于现场调查和室内分析,本文在明确滑坡区地质结构和地形条件对坡体渗流场产生重要影响的基础上,立足于当地气象资料,利用SEEP/W模块和FLAC3D软件继续探究降雨工况下滑坡变形失稳的进程,初步阐述了多期降雨诱发该类推移式堆积层滑坡(H1)及其引发的次生牵引式滑坡(H2)的成因机理。研究成果表明,主滑坡受历史罕见的强降雨诱导开启失稳变形进程,但受制于地形条件,具有分段失稳、渐进破坏等特点。在滑坡长期蠕动变形过程中,多期降雨导致地下水位浮动变化,刺激滑体蠕变加剧。次级牵引式滑坡由于临空条件受主滑坡控制,其演化进程与主滑坡失稳变形表现出明显关联性和一定滞后性。推移式堆积层主滑坡受地形、地下水和荷载等因素影响,从滑带参数弱化到滑面蠕滑贯通需经历长期过程;而牵引式堆积层次级滑坡是由于关键阻滑体的缺失,导致坡体应力重分布产生的后退式滑动,一般历时较短。
At the beginning of 2011,affected by multi-periods of heavy rainfall,many geohazards were developed on the accumulated layer slopes in Shuimatuo Town,Sinan County. They include ground surface rupture,wall inclination,deformation aggravation of fissures on ground and walls. Once influenced by the heavy rainfall and other unfavorable factors,the unstable slopes would slide continuously,posing a serious threat to the 509 persons and556 houses of Datong Community,and a significantly negative impact to the local society. Based on the field survey and indoor analysis,this paper elaborates the geo-environmental characteristics of the Shuimatuo landslide region and clarifies the important effects of geological structures and topographic conditions to the seepage field of the slope. With the help of local meteorological data,we continue to research the deformation and failure process of the slope under the rainfall condition with the SEEP/W module and the FLAC3 Dsoftware. We preliminarily expound the formation mechanism of the thrust-type landslide( H1) and secondary tractive landslide( H2) triggered by the multiperiod of rainfall. The preliminary research results believe that induced by the rare heavy rainfall in the history,the major landslide begins to deform, but limited by the terrain condition, showing characteristics of part and progressive failure. During the long-term creep deformation process of landslide,rainfall causes a fluctuation of the groundwater level, strengthening the creep of sliding mass. Controlled by the free surface condition, the evolutionary process of secondary tractive landslide shows obvious correlation and certain lag comparing to the major landslide. For the thrust-type accumulated layer landslide,affected by the terrain,groundwater and loading conditions,it takes a long time from strength decrease of sliding belt to the formation of sliding plane. While tractive accumulated layer landslide lasts shortly as it is a backward movement generated by slope stress redistribution due to the lack of key anti-slide body.
At the beginning of 2011,affected by multi-periods of heavy rainfall,many geohazards were developed on the accumulated layer slopes in Shuimatuo Town,Sinan County. They include ground surface rupture,wall inclination,deformation aggravation of fissures on ground and walls. Once influenced by the heavy rainfall and other unfavorable factors,the unstable slopes would slide continuously,posing a serious threat to the 509 persons and556 houses of Datong Community,and a significantly negative impact to the local society. Based on the field survey and indoor analysis,this paper elaborates the geo-environmental characteristics of the Shuimatuo landslide region and clarifies the important effects of geological structures and topographic conditions to the seepage field of the slope. With the help of local meteorological data,we continue to research the deformation and failure process of the slope under the rainfall condition with the SEEP/W module and the FLAC3 Dsoftware. We preliminarily expound the formation mechanism of the thrust-type landslide( H1) and secondary tractive landslide( H2) triggered by the multiperiod of rainfall. The preliminary research results believe that induced by the rare heavy rainfall in the history,the major landslide begins to deform, but limited by the terrain condition, showing characteristics of part and progressive failure. During the long-term creep deformation process of landslide,rainfall causes a fluctuation of the groundwater level, strengthening the creep of sliding mass. Controlled by the free surface condition, the evolutionary process of secondary tractive landslide shows obvious correlation and certain lag comparing to the major landslide. For the thrust-type accumulated layer landslide,affected by the terrain,groundwater and loading conditions,it takes a long time from strength decrease of sliding belt to the formation of sliding plane. While tractive accumulated layer landslide lasts shortly as it is a backward movement generated by slope stress redistribution due to the lack of key anti-slide body.
引文
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Song D R,Ren W Z,Shen B,et al.2013.Discussion on failure mechanism of retrogressive landslide and its reinforcement measures:taking a certain expressway retrogressive landslide for example[J].Rock and Soil Mechanics,34(12):3587-3593.
Wang G,Sun P,Wu L Z,et al.2017.Experimental study on mechanism of shallow loess landslides induced by rainfall[J].Journal of Engineering Geology,25(5):1252-1263.
Wu H Z,Feng M G,Jiao Y Y,et al.2010.Analysis of sliding mechanism of accumulation horizon landslide under rainfall condition[J].Rock and Soil Mechanics,31(S1):324-329.
Zhang Q,Xu Q,Ning N.2014.A study of the stability influence factors and coupling for inclined-shallow soil landslides under the condition of rainfall[J].Hydrogeology&Engineering Geology,41(5):90-94,117.
Zhou Y T,Chen H K,Zhang Y,et al.2016.Failure of super-huge landslide in collapsed debris deposits with nearly horizontal sliding surface induced by excess pore water pressure[J].Journal of Engineering Geology,24(5):732-740.
成国文,李善涛,李晓,等.2008.万州近水平地层区堆积层滑坡成因与变形破坏特征[J].工程地质学报,16(3):304-310.
陈善雄,许锡昌,徐海滨.2005.降雨型堆积层滑坡特征及稳定性分析[J].岩土力学,26(增刊1):6-10.
代贞伟,李滨,陈云霞,等.2016.三峡大树场镇堆积层滑坡暴雨失稳机理研究[J].水文地质工程地质,43(1):149-156.
冯文凯,胡云鹏,谢吉尊,等.2016.顺层震裂斜坡降雨触发灾变机制及稳定性分析——以三溪村滑坡为例[J].岩石力学与工程学报,35(11):2197-2207.
贺可强,王荣鲁,李新志,等.2008.堆积层滑坡的地下水加卸载动力作用规律及其位移动力学预测——以三峡库区八字门滑坡分析为例[J].岩石力学与工程学报,27(8):1644-1651.
宋东日,任伟中,沈波,等.2013.牵引式滑坡的破坏机制及其加固措施探讨——以某高速公路牵引式滑坡为例[J].岩土力学,34(12):3587-3593.
王刚,孙萍,吴礼舟,等.2017.降雨诱发浅表层黄土滑坡机理实验研究[J].工程地质学报,25(5):1252-1263.
吴火真,冯美果,焦玉勇,等.2010.降雨条件下堆积层滑坡体滑动机制分析[J].岩土力学,31(增刊1):324-329.
张群,许强,甯娜.2014.降雨条件下低缓浅层土质滑坡稳定性影响因素及耦合研究[J].水文地质工程地质,41(5):90-94,117.
周云涛,陈洪凯,张勇,等.2016.超孔隙水压诱发特大型近水平崩坡积层滑坡破坏研究[J].工程地质学报,24(5):732-740.
Chen G W,Li S T,Li X,et al.2008.Forming causes and deformationdestruction characters of accumulative stratum landslide in horizontal stratum in Wanzhou[J].Journal of Engineering Geology,16(3):304-310.
Chen S X,Xu X C,Xu H B.2005.Features and stability analysis of rainfall-induced colluvial landslides[J].Rock and Soil Mechanics,26(Sl):6-10.
Dai Z W,Li B,Chen Y X,et al.2016.A study of the failure mechanism of rainfall-induced accumulation landslide in the Three Gorges Reservoir region[J].Hydrogeology&Engineering Geology,43(1):149-156.
Feng W K,Hu Y P,Xie J Z,et al.2016.Disaster mechanism and stability analysis of bedding slopes triggered by rainfall-A case study of shattered Sanxicun landslide[J].Chinese Journal of Rock Mechanics and Engineering,35(11):2197-2207.
He K Q,Wang R L,Li X Z,et al.2008.Load-unload dynamic law of groundwater level and dynamic displacement prediction of debris landslide-A case study of bazimen landslide in three gorges reservoir[J].Chinese Journal of Rock Mechanics and Engineering,27(8):1644-1651.
Marko K,Tiit H,Peeter T,et al.2010.Analysis of retrogressive landslide in glaciolacustrine vary clay[J].Engineering Geology,116(1-2):109-116.
Song D R,Ren W Z,Shen B,et al.2013.Discussion on failure mechanism of retrogressive landslide and its reinforcement measures:taking a certain expressway retrogressive landslide for example[J].Rock and Soil Mechanics,34(12):3587-3593.
Wang G,Sun P,Wu L Z,et al.2017.Experimental study on mechanism of shallow loess landslides induced by rainfall[J].Journal of Engineering Geology,25(5):1252-1263.
Wu H Z,Feng M G,Jiao Y Y,et al.2010.Analysis of sliding mechanism of accumulation horizon landslide under rainfall condition[J].Rock and Soil Mechanics,31(S1):324-329.
Zhang Q,Xu Q,Ning N.2014.A study of the stability influence factors and coupling for inclined-shallow soil landslides under the condition of rainfall[J].Hydrogeology&Engineering Geology,41(5):90-94,117.
Zhou Y T,Chen H K,Zhang Y,et al.2016.Failure of super-huge landslide in collapsed debris deposits with nearly horizontal sliding surface induced by excess pore water pressure[J].Journal of Engineering Geology,24(5):732-740.
成国文,李善涛,李晓,等.2008.万州近水平地层区堆积层滑坡成因与变形破坏特征[J].工程地质学报,16(3):304-310.
陈善雄,许锡昌,徐海滨.2005.降雨型堆积层滑坡特征及稳定性分析[J].岩土力学,26(增刊1):6-10.
代贞伟,李滨,陈云霞,等.2016.三峡大树场镇堆积层滑坡暴雨失稳机理研究[J].水文地质工程地质,43(1):149-156.
冯文凯,胡云鹏,谢吉尊,等.2016.顺层震裂斜坡降雨触发灾变机制及稳定性分析——以三溪村滑坡为例[J].岩石力学与工程学报,35(11):2197-2207.
贺可强,王荣鲁,李新志,等.2008.堆积层滑坡的地下水加卸载动力作用规律及其位移动力学预测——以三峡库区八字门滑坡分析为例[J].岩石力学与工程学报,27(8):1644-1651.
宋东日,任伟中,沈波,等.2013.牵引式滑坡的破坏机制及其加固措施探讨——以某高速公路牵引式滑坡为例[J].岩土力学,34(12):3587-3593.
王刚,孙萍,吴礼舟,等.2017.降雨诱发浅表层黄土滑坡机理实验研究[J].工程地质学报,25(5):1252-1263.
吴火真,冯美果,焦玉勇,等.2010.降雨条件下堆积层滑坡体滑动机制分析[J].岩土力学,31(增刊1):324-329.
张群,许强,甯娜.2014.降雨条件下低缓浅层土质滑坡稳定性影响因素及耦合研究[J].水文地质工程地质,41(5):90-94,117.
周云涛,陈洪凯,张勇,等.2016.超孔隙水压诱发特大型近水平崩坡积层滑坡破坏研究[J].工程地质学报,24(5):732-740.
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