不同排水条件下砂-黄土界面的剪切力学特性
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摘要
为了研究异质土在不同排水条件下的力学机理,进行了一系列环剪试验,对单一黄土、单一砂、砂-黄土组成的异质土在剪切力学特性上的差异及其产生机理进行了比较分析。结果表明:在不同排水条件下,砂-黄土组成的异质土在相互接触剪切的过程中,剪切应力变化形态和抗剪强度与单一黄土、单一砂之间存在显著差异,即砂-黄土组成的异质土在其剪切过程中呈现出了黏性土的剪切力学特征;在相同剪切速率条件下,砂-黄土组成的异质土在不同排水条件下的抗剪强度比单一黄土和单一砂的抗剪强度至少降低了71%和51%。不同排水条件下砂-黄土的剪切力学性质出现了差异,其主要原因与剪切面处砂与黄土之间的相互作用以及剪切面处土体内孔隙水状态有关。
In order to study mechanical characteristics of heterogeneous soils under different conditions,the authors conducted a series of ring shear tests,and compared the differences of shear mechanical characteristics between loess,sand,and heterogeneous soils composed of sand and loess.A comparative analysis was carried out on the differences and their generation mechanisms.The study results showed that under different drainage conditions,the change form of shear stress and shear strength of heterogeneous soil composed of sand and loess were significant different from those of loess or sand during the mutual shearing process.At the same shearing rate,when compared with those of single loess and single sand,the shear strength of sand-loess under different drainage conditions was decreased by 71%and 51%,respectively.During the shearing process,the heterogeneous soil composed of sand and loess presented the shearing mechanical characteristics of cohesive soil.The mechanical characteristic differences between heterogeneous soils and single loess or single sand under different drainage conditions are mainly related to the interaction between sand and loess on the shearing surface and pore water state inside soil body.
In order to study mechanical characteristics of heterogeneous soils under different conditions,the authors conducted a series of ring shear tests,and compared the differences of shear mechanical characteristics between loess,sand,and heterogeneous soils composed of sand and loess.A comparative analysis was carried out on the differences and their generation mechanisms.The study results showed that under different drainage conditions,the change form of shear stress and shear strength of heterogeneous soil composed of sand and loess were significant different from those of loess or sand during the mutual shearing process.At the same shearing rate,when compared with those of single loess and single sand,the shear strength of sand-loess under different drainage conditions was decreased by 71%and 51%,respectively.During the shearing process,the heterogeneous soil composed of sand and loess presented the shearing mechanical characteristics of cohesive soil.The mechanical characteristic differences between heterogeneous soils and single loess or single sand under different drainage conditions are mainly related to the interaction between sand and loess on the shearing surface and pore water state inside soil body.
引文
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[16]洪勇,孙涛,栾茂田,等.土工环剪仪的开发及其应用研究现状[J].岩土力学,2009,30(3):628-634.Hong Yong,Sun Tao,Luan Maotian,et al.Development and Application of Geotechnical Ring Shear Apparatus:An Overview[J].Rock and Soil Mechanics,2009,30(3):628-634.
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[18]洪勇,许强,郑孝玉.超固结粉质黏土快速大剪切力学特性[J].工程地质学报,2013,21(5):696-701.Hong Yong,Xu Qiang,Zheng Xiaoyu.Mechanical Properties of Over Consolidated Silty Clay under Fast Shear Conditions[J].Journal of Engineering Geology,2013,21(5):696-701.
[19]Skernpton A W.Residual Strength of Clays in Landsides,Folded Strata and the Laboratory[J].Geotechnique,1985,35(1):3-5.
[2]张常亮,王阿丹,邢鲜丽,等.侵蚀作用诱发黄土滑坡的机制研究[J].岩土力学,2012,33(5):1585-1592.Zhang Changliang,Wang Adan,Xing Xianli,et al.Research on Mechanism of Loess Landslides Caused by Erosion[J].Rock and Soil Mechanics,2012,33(5):1585-1592.
[3]金艳丽,戴福初.灌溉诱发黄土滑坡机理研究[J].岩土工程学报,2007,29(10):1493-1499.Jin Yanli,Dai Fuchu.The Mechanism of IrrigationInduced Landslides of Loess[J].Chinese Journal of Geotechnical Engineering,2007,29(10):1493-1499.
[4]段钊,彭建兵,王启耀.泾阳南塬黄土滑坡的运动规律与液化效应[J].水土保持通报,2016,36(3):46-49.Duan Zhao,Peng Jianbing,Wang Qiyao.Motion Law and Liquefaction Effect of Loess Landslides in South Jingyang Plateau[J].Bulletin of Soil and Water Conservation,2016,36(3):46-49.
[5]黄强兵,刘悦,彭建兵.黄土路堑边坡变形破坏机理的三轴试验研究[J].工程地质学报,2007,15(6):806-811.Huang Qiangbing,Liu Yue,Peng Jianbing.Triaxial Test Study on the Deformation and Failure Mechanism of Loess Cut Slope[J].Journal of Engineering Geology,2007,15(6):806-811.
[6]许领,戴福初,闵弘,等.泾阳南塬黄土滑坡类型与发育特征[J].地球科学:中国地质大学学报,2010,35(1):155-160.Xu Ling,Dai Fuchu,Min Hong,et al.Loess Landslide Types and Topographic Features at South Jingyang Plateau,China[J].Earth Science:Journal of China University of Geosciences,2010,35(1):155-160.
[7]许领,戴福初,邝国麟,等.黄土滑坡典型工程地质问题分析[J].岩土工程学报,2009,31(2):287-293.Xu Ling,Dai Fuchu,Kuang Guolin,et al.Analysis of Some Special Engineering-Geological Problems of Loess Landslide[J].Chinese Journal of Geotechnical Engineering,2009,31(2):287-293.
[8]Sassa K.A New Intelligent Type of Dynamic Loading Ring Shear Apparatus[J].Landslide News(Japanese Landslide Society),1997,10:33.
[9]孙涛,洪勇,栾茂田,等.采用环剪仪对超固结黏土抗剪强度特性的研究[J].岩土力学,2009,30(7):2000-2004.Sun Tao,Hong Yong,Luan Maotian,et al.Shear Strength Behavior of Over Consolidated Clay in Ring Shear Test[J].Rock and Soil Mechanics,2009,30(7):2000-2004.
[10]Wang G H,Sassa K,Fukuoka H,et al.Experimental Study on the Shearing Behavior of Saturated Silty Soils Based on Ring-Shear Tests[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(3):319-333.
[11]Wang F W,Sassa K,Wang G H.Mechanism of a Long-Runout Landslide Triggered by the August1998Heavy Rainfall in Fukushima Prefecture,Japan[J].Engineering Geology,2002,63(1/2):169-185.
[12]Hong Y,Yu G M.Effect of Cyclic Loading on the Residual Strength of Over-Consolidated Silty Clay in a Ring Shear Test[J].Landslides:Journal of International Consortium on Landslides,2011,8(2):233-240.
[13]Hong Y,Yu G M,Li L.Fast Shear Behaviors of Over Consolidated Silty Clay in Ring Shear Tests[C]//Proceedings of 11th Congress of the International Association for Engineering Geology and the Environment.Aucland:[s.n.],2010:1915-1922.
[14]洪勇,岳玉秋,郑孝玉,等.大连滨海粉质黏土剪切力学特性环剪试验[J].吉林大学学报(地球科学版),2016,46(5):1475-1481.Hong Yong,Yue Yuqiu,Zheng Xiaoyu,et al.Shear Strength of Silty Clay in Dalian by Ring Shear Tests[J].Journal of Jilin University(Earth Science Edition),2016,46(5):1475-1481.
[15]洪勇,车效文,郑孝玉,等.陕西泾阳南塬滑坡干湿黄土快速大剪切力学特性[J].吉林大学学报(地球科学版),2017,47(4):1207-1218.Hong Yong,Che Xiaowen,Zheng Xiaoyu,et al.Fast Shear Behavior of Saturated and Dry Loess at South Plateau Landslide of Jingyang,Shaanxi[J].Journal of Jilin University(Earth Science Edition),2017,47(4):1207-1218.
[16]洪勇,孙涛,栾茂田,等.土工环剪仪的开发及其应用研究现状[J].岩土力学,2009,30(3):628-634.Hong Yong,Sun Tao,Luan Maotian,et al.Development and Application of Geotechnical Ring Shear Apparatus:An Overview[J].Rock and Soil Mechanics,2009,30(3):628-634.
[17]土的工程分类标准:GB/T 50145-2007[S].北京:中国计划出版社,2008.Standardfor Engineering Classification of Soil:GB/T50145-2007[S].Beijing:China Planning Press,2008.
[18]洪勇,许强,郑孝玉.超固结粉质黏土快速大剪切力学特性[J].工程地质学报,2013,21(5):696-701.Hong Yong,Xu Qiang,Zheng Xiaoyu.Mechanical Properties of Over Consolidated Silty Clay under Fast Shear Conditions[J].Journal of Engineering Geology,2013,21(5):696-701.
[19]Skernpton A W.Residual Strength of Clays in Landsides,Folded Strata and the Laboratory[J].Geotechnique,1985,35(1):3-5.