基于随机场理论的强降雨条件下花岗岩残积土边坡的稳定性分析
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摘要
花岗岩残积土具有明显的空间变异性,采用随机场方法研究了土体力学参数空间变异性对强降雨条件下花岗岩残积土边坡的稳定性的影响。采用湿润锋模型模拟强降雨条件下边坡中孔隙水压力分布,采用随机场模拟土体强度参数的空间变异性,采用强度折减法计算边坡的安全系数。研究表明:土体空间变异性可改变边坡的失效模式,随着土体空间相关距离的减少,滑体体积减小;考虑土体空间变异性后,边坡的失效概率对湿润锋的增加更为敏感,忽略土体内聚力和内摩擦角之间的负相关性会高估边坡的失效概率。
Completely decomposed granite( CDG) is subjected to substantial amount of spatial variability. The purpose of this paper is to investigate the effect of spatial variability of the shear strength parameters of CDG on the stability of CDG slopes under intense rainfall infiltration. In the method used in this paper,the pore water pressure is modeled using the wetting font concept. The spatial variability of the strength parameters is modeled based on the random fields. The factor of safety of the slope is computed using the shear strength reduction method. It is found that the presence of spatial variability will change the failure modes of the slope. As the correlation distance reduces,the size of the sliding mass also tends to reduce. The stability of the soil will be more sensitive to the advancing of the wetting front. Ignoring the negative correlation between the cohesion and the friction angle will overestimate underestimate the failure probability of the slope.
Completely decomposed granite( CDG) is subjected to substantial amount of spatial variability. The purpose of this paper is to investigate the effect of spatial variability of the shear strength parameters of CDG on the stability of CDG slopes under intense rainfall infiltration. In the method used in this paper,the pore water pressure is modeled using the wetting font concept. The spatial variability of the strength parameters is modeled based on the random fields. The factor of safety of the slope is computed using the shear strength reduction method. It is found that the presence of spatial variability will change the failure modes of the slope. As the correlation distance reduces,the size of the sliding mass also tends to reduce. The stability of the soil will be more sensitive to the advancing of the wetting front. Ignoring the negative correlation between the cohesion and the friction angle will overestimate underestimate the failure probability of the slope.
引文
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[10]CORNELL C A.First-order uncertainty analysis of soil deformation and stability[J].Publication of University of Hong Kong,1972:129-144.
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[14]CHO S E.Probabilistic assessment of slope stability that considers the spatial variability of soil properties[J].Journal of Geotechnical and Geoenvironmental Engineering,2010,136(7):975-984.
[15]薛亚东,方超,葛嘉诚.各向异性随机场下的边坡可靠度分析[J].岩土工程学报,2013,35(增刊2):77-82.XUE Y D,FANG C,GE J C.Slope reliability in anisotropic random fields[J].Chinese Journal of Geotechnical Engineering,2013,35(Supp.2):77-82.
[16]蒋水华,李典庆,曹子君,等.考虑参数空间变异性的边坡可靠度及其敏感性分析多重响应面法[J].防灾减灾工程学报,2015,35(5):592-598.JIANG S H,LI D Q,CAO Z J,et al.Multiple response surfaces method for probabilistic analysis and reliability sensitivity analysis of slopes considering spatially varying soil properties[J].Journal of Disaster Prevention and Mitigation Engineering,2015,35(5):592-598.
[17]CHO S E.Infiltration analysis to evaluate the surficial stability of two-layered slopes considering rainfall characteristics[J].Engineering Geology,2009,105(1-2):32-43.
[18]LUMB P.Effect of rain storms on slope stability[C]//Proceedings of the Symposium on Hong Kong Soils.Hong Kong,1962:537-552.
[19]FOURIE A B,ROEW D,BLIGHT G E.The effect of infiltration on the stability of the slopes of a dry ash dump[J].Géotechnique,1999,49(1):1-13.
[20]VANAPALLI S K,FREDLUND D G,PUFAHL D E,et al.Model for the prediction of shear strength with respect to soil suction[J].Canadian Geotechnical Journal,1996,33(3):379-392.
[21]FREDLUND D G,XING A.Equations for the soil-water characteristic curve[J].Canadian Geotechnical Journal,1994,31(4):521-532.
[22]陈宏智.基于可靠度理论的高铁复合地基沉降预测方法[D].上海:同济大学土木工程学院地下建筑与工程系,2016.
[23]肖特,李典庆,周创兵,等.基于有限元强度折减法的多层边坡非侵入式可靠度分析[J].应用基础与工程科学学报,2014(4):718-732.XIAO T,LI D Q,ZHOU C B,et al.Non-intrusive reliability analysis of multi-layered slopes using strength reduction FEM[J].Journal of Basic Science and Engineering,2014(4):718-732.
[24]UGAI K.A method of calculation of total safety factor of slope by elasto-plastic FEM[J].Soils&Foundations,1989,29(2):190-195.
[25]LUMB P.Safety factors and the probability distribution of soil strength[J].Canadian Geotechnical Journal,1970,7(3):225-242.
[2]HU J Z,WANG H,MA J Z,et al.Probabilistic assessment of the properties of completely decomposed granite[C]//Tongji University.Proceedings of the 6th Asian-Pacific Symposium on Structural Reliability and Its Applications.Shanghai,China,May 28-30,2016.Shanghai:Tongji University,2016:480-486.
[3]梁仕华,周世宗,张朗,等.广州东部地区花岗岩残积土物理力学指标统计分析[J].广东工业大学学报,2015,32(1):29-33.LIANG S H,ZHOU S Z,ZHANG L,et al.Statistical analysis of physical and mechanical indexes of granite residual soil in eastern guangzhou[J].Journal of Guangdong University of Technology,2015,32(1):29-33.
[4]陈洪江,崔冠英.花岗岩残积土物理力学指标的概型分布检验[J].华中科技大学学报(自然科学版),2001,29(5):92-94.CHEN H J,CUI G Y.Probability type testing of the distribution on the granite eluvial soil mechanical parameters[J].Journal of Huazhong University of Science and Technology(Natural Science Edition),2001,29(5):92-94.
[5]张灿亨,王鑫,郑文棠.基于水动力学模型的暴雨浅层滑坡风险分析[J].南方能源建设,2015,2(增刊1):198-202.ZHANG C H,WANG X,ZHENG W T.Assessment of rainstorminduced shallow landslide hazard with hydrody-namic model[J].Southern Energy Construction,2015,2(Supp.1):198-202.
[6]蒋中明,熊小虎,曾铃.基于FLAC~(3D)平台的边坡非饱和降雨入渗分析[J].岩土力学,2014,35(3):855-861.JIANG Z M,XIONG X H,ZENG L.Unsaturated seepage analysis of slope under rainfall condition based on FLAC3D[J].Rock and Soil Mechanics,2014,35(3):855-861.
[7]郑敏洲,简文彬,吴茂明.花岗岩残积土边坡稳定性可靠度分析[J].岩石力学与工程学报,2005,24(增刊2):5337-5340.ZHENG M Z,JIAN W B,WU M M.Reliability analysis of stability of granite residual soil slope[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(Supp.2):5337-5340.
[8]ZHANG L L,ZHANG L M,TANG W H.2005 Rainfall-induced slope failure considering variability of soil properties[J].Geotechnique,55(2):183-188.
[9]WANG H,ZHANG J,ZHENG W T,et al.System reliability analysis of slopes made of completely decomposed granite under intense rainfall infiltration[C]//Tongji University.Proceedings of the 6th Asian-Pacific Symposium on Structural Reliability and Its Applications.Shanghai,China,May 28-30,2016.Shanghai:Tongji University,2016:406-411.
[10]CORNELL C A.First-order uncertainty analysis of soil deformation and stability[J].Publication of University of Hong Kong,1972:129-144.
[11]GRIFFITHS D V,FENTON G A.Probabilistic slope stability analysis by finite elements[J].Journal of Geotechnical and Geoenvironmental Engineering,2004,130(5):507-518.
[12]史良胜,杨金忠,陈伏龙,等.Karhunen-Loeve展开在土性各向异性随机场模拟中的应用研究[J].岩土力学,2007,28(11):2303-2308.SHI L S,YANG J Z,CHEN F L,et al.Research on application of Karhunen-Loeve expansion to simulating anisotropic random field of soil property[J].Rock and Soil Mechanics,2007,28(11):2303-2308.
[13]吴振君,王水林,葛修润.约束随机场下的边坡可靠度随机有限元分析方法[J].岩土力学,2009,30(10):3086-3092.WU Z J,WANG S L,GE X R.Slope reliability analysis by random FEM under constraint random field[J].Rock and Soil Mechanics,2009,30(10):3086-3092.
[14]CHO S E.Probabilistic assessment of slope stability that considers the spatial variability of soil properties[J].Journal of Geotechnical and Geoenvironmental Engineering,2010,136(7):975-984.
[15]薛亚东,方超,葛嘉诚.各向异性随机场下的边坡可靠度分析[J].岩土工程学报,2013,35(增刊2):77-82.XUE Y D,FANG C,GE J C.Slope reliability in anisotropic random fields[J].Chinese Journal of Geotechnical Engineering,2013,35(Supp.2):77-82.
[16]蒋水华,李典庆,曹子君,等.考虑参数空间变异性的边坡可靠度及其敏感性分析多重响应面法[J].防灾减灾工程学报,2015,35(5):592-598.JIANG S H,LI D Q,CAO Z J,et al.Multiple response surfaces method for probabilistic analysis and reliability sensitivity analysis of slopes considering spatially varying soil properties[J].Journal of Disaster Prevention and Mitigation Engineering,2015,35(5):592-598.
[17]CHO S E.Infiltration analysis to evaluate the surficial stability of two-layered slopes considering rainfall characteristics[J].Engineering Geology,2009,105(1-2):32-43.
[18]LUMB P.Effect of rain storms on slope stability[C]//Proceedings of the Symposium on Hong Kong Soils.Hong Kong,1962:537-552.
[19]FOURIE A B,ROEW D,BLIGHT G E.The effect of infiltration on the stability of the slopes of a dry ash dump[J].Géotechnique,1999,49(1):1-13.
[20]VANAPALLI S K,FREDLUND D G,PUFAHL D E,et al.Model for the prediction of shear strength with respect to soil suction[J].Canadian Geotechnical Journal,1996,33(3):379-392.
[21]FREDLUND D G,XING A.Equations for the soil-water characteristic curve[J].Canadian Geotechnical Journal,1994,31(4):521-532.
[22]陈宏智.基于可靠度理论的高铁复合地基沉降预测方法[D].上海:同济大学土木工程学院地下建筑与工程系,2016.
[23]肖特,李典庆,周创兵,等.基于有限元强度折减法的多层边坡非侵入式可靠度分析[J].应用基础与工程科学学报,2014(4):718-732.XIAO T,LI D Q,ZHOU C B,et al.Non-intrusive reliability analysis of multi-layered slopes using strength reduction FEM[J].Journal of Basic Science and Engineering,2014(4):718-732.
[24]UGAI K.A method of calculation of total safety factor of slope by elasto-plastic FEM[J].Soils&Foundations,1989,29(2):190-195.
[25]LUMB P.Safety factors and the probability distribution of soil strength[J].Canadian Geotechnical Journal,1970,7(3):225-242.