干湿循环下粉质黏土强度及变形特性试验研究
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摘要
为了研究干湿循环作用下粉质黏土强度及变形特性的变化规律,以取自三峡库区某边坡的原状粉质黏土为研究对象,通过干湿循环和三轴剪切试验,对不同荷载条件下,经历不同干湿循环次数的粉质黏土的强度和变形进行了研究。结果表明:随着干湿循环次数的增加,强度峰值、有效黏聚力和割线模量都逐渐降低,且先快后慢;而有效内摩擦角保持稳定。干湿循环对原状粉质黏土强度和变形特性的劣化是因为裂隙的开展破坏了土体的结构。荷载约束了干湿循环时裂隙开展,从而抑制了干湿循环的劣化作用,荷载越大,抑制能力越强。最后,通过拟合试验数据,对干湿循环作用下的原状粉质黏土的摩尔-库仑强度准则表达式进行了修正。
To study the strength and deformation characteristics of silty clay during wetting-drying cycles, the undisturbed silty clay is taken from a slope located in Three Gorges Reservoir Region, China. A series of triaxial shear tests are conducted under different load conditions after wetting-drying cycles. The test results indicate that the peak strength, effective cohesion and secant modulus all decrease slowly with the increasing number of wetting-drying cycles. While the effective internal friction angle stays at a steady state. The reason for the deterioration of strength and deformation of the silty clay in wetting-drying cycles is the crack development, which undermines the soil structure. However, external loading can positively restrict the crack development caused by wetting-drying cycles. By fitting the test data, the expression of Mohr-Coulomb yielding criterion for the undisturbed silty clay under wetting-drying cycles is modified.
To study the strength and deformation characteristics of silty clay during wetting-drying cycles, the undisturbed silty clay is taken from a slope located in Three Gorges Reservoir Region, China. A series of triaxial shear tests are conducted under different load conditions after wetting-drying cycles. The test results indicate that the peak strength, effective cohesion and secant modulus all decrease slowly with the increasing number of wetting-drying cycles. While the effective internal friction angle stays at a steady state. The reason for the deterioration of strength and deformation of the silty clay in wetting-drying cycles is the crack development, which undermines the soil structure. However, external loading can positively restrict the crack development caused by wetting-drying cycles. By fitting the test data, the expression of Mohr-Coulomb yielding criterion for the undisturbed silty clay under wetting-drying cycles is modified.
引文
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[14]KAMPALA A,HORPIBULSUK S,PRONGMANEE N.Influence of wet-dry cycles on compressive strength of calcium carbide residue–fly ash stabilized clay[J].Journal of Materials in Civil Engineering,2014,26(4):633-643.
[15]ALDAOOD A,BOUASKER M,AL-MUKHTAR M.Impact of wetting–drying cycles on the microstructure and mechanical properties of lime-stabilized gypseous soils[J].Engineering Geology,2014,174:11-21.
[16]RAYHANIA M H T,YANFULB E K,FAKHER A.Physical modeling of desiccation cracking in plastic soils[J].Engineering Geology,2008,97:25-31.
[17]RAYHANIA M H T,YANFULB E K,FAKHER A.Desiccation induced cracking and its effect on hydraulic conductivity of clayey soils from Iran[J].Canadian Geotechnical Journal,2007,44:276-283.
[18]张家俊,龚壁卫,胡波.干湿循环作用下膨胀土裂隙演化规律试验研究[J].岩土力学,2011,32(9):2729-2734.ZHANG Jia-jun,GONG Bi-wei,HU Bo.Study of evolution law of fissures of expansive clay under wetting and drying cycles[J].Rock and Soil Mechanics,2011,32(9):2729-2734.
[19]NOWAMOOZ H,JAHANGIR E,MASROURI F.Volume change behavior of a swelling soil compacted at different initial states[J].Engineering Geology,2013,153:25-34.
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[21]杨和平,王兴正,肖杰.干湿循环效应对南宁外环膨胀土抗剪强度的影响[J].岩土工程学报,2014,36(5):949-954.YANG He-ping,WANG Xing-zheng,XIAO Jie.Influence of wetting-drying cycles on strength characteristics of Nanning expansive soils[J].Chinese Journal of Geotechnical Engineering,2014,36(5):949-954.
[22]肖杰,杨和平,王兴正,等.南宁外环膨胀土抗剪强度非线性特征及影响因素分析[J].中国公路学报,2014,27(10):1-8.XIAO Jie,YANG He-ping,WANG Xing-zheng.Analysis of nonlinear characteristics of shear strength of Nanning expansive soil and its influencing factors[J].Chinese Journal of Highway and Transport,2014,27(10):1-8.
[23]邓华锋,肖瑶,方景成,等.干湿循环作用下岸坡消落带土体抗剪强度劣化规律及其对岸坡稳定性影响研究[J].岩土力学,2017,38(9):2629-2638.DENG Hua-feng,XIAO Yao,FANG Jing-cheng,,et al.Shear strength degradation and slope stability of soils at hydro-fluctuation belt of river bank slope during drying-wetting cycle[J].Rock and Soil Mechanics,2017,38(9):2629-2638.
[24]中华人民共和国行业标准.SL237-1999土工试验规程[S].北京:中国水利水电出版社,1999.The Professional Standards Compilation Group of Peoples Republic of China.SL237-1999 Specification of soil test[S].Beijing:China Water Power Press,1999.
[25]孔纲强,刘璐,刘汉龙,等.玻璃砂透明土变形特性三轴试验研究[J].岩土工程学报,2013,35(6):1140-1146.KONG Gang-qiang,LIU Lu,LIU Han-long,et al.Triaxial tests on deformation characteristics of transparent glass sand[J].Chinese Journal of Geotechnical Engineering,2013,35(6):1140-1146.
[26]《工程地质手册》编委会.工程地质手册[M].北京:中国建筑工业出版社,2007.“Engineering Geology Handbook”Editorial Board.Handbook of engineering geology[M].Beijing:Chinese Building Industry Press,2007.
[27]李广信.高等土力学[M].北京:清华大学出版社,2004.LI Guang-xin.Advanced soil mechanics[M].Beijing:Tsinghua University Press,2004.
[28]叶为民,万敏,陈宝,等.干湿循环条件下高压实膨润土的微观结构特征[J].岩土工程学报,2011,33(8):1173-1177.YE Wei-min,WAN Min,CHEN Bao,et al.Micro-structural behaviors of densely compacted GMZ01bentonite under drying/wetting cycles[J].Chinese Journal of Geotechnical Engineering,2011,33(8):1173-1177.
[2]刘文化,杨庆,唐小微,等.干湿循环条件下不同初始干密度土体的力学特性[J].水利学报,2014,45(3):261LIU Wen-hua,YANG Qing,TANG Xiao-wei,et al.Mechanical behaviors of soils with different initial dry densities under drying-wetting cycle[J].Journal of Hydraulic Engineering,2014,45(3):261-268.
[3]刘文化,杨庆,唐小微,等.干湿循环条件下粉质黏土在循环荷载作用下的动力特性试验研究[J].水利学报,2015,46(4):425-432.LIU Wen-hua,YANG Qing,TANG Xiao-wei,et al.Experimental study on the dynamic characteristics of silt clay subjected to drying-wetting cycles under cyclic loading[J].Journal of Hydraulic Engineering,2015,46(4):425-432.
[4]刘文化,杨庆,唐小微,等.交通荷载作用下非饱和土的动力特性试验研究[J].防灾减灾工程学报,2015,35(2):263-269.LIU Wen-hua,YANG Qing,TANG Xiao-wei,et al.Experimental study on the dynamic characteristics of unsaturated soils under traffic loading[J].Journal of Disaster Prevention and Mitigation Engineering,2015,35(2):263-269.
[5]刘文化,杨庆,唐小微,等.制样方法和干湿循环对粉质黏土土-水特征曲线影响[J].大连理工大学学报,2015,55(2):179-184.LIU Wen-hua,YANG Qing,TANG Xiao-wei,et al.effects of specimen preparation method and dryingwetting cycle on soil water characteristic curves of silty clay[J].Journal of Dalian University of Technology,2015,55(2):179-184.
[6]邓志永.干湿循环对粉质黏土路堤边坡稳定性影响分析[J].湖南交通科技,2015,41(1):14-16.DENG Zhi-yong.Analysis on silty clay embankment slope stability under drying-wetting cycles influence[J].Hunan Communication Science and Technology,2015,41(1):14-16.
[7]孙德安,黄丁俊.干湿循环下南阳膨胀土的土水和变形特性[J].岩土力学,2015,36(增刊1):115-119.SUN De-an,HUANG Ding-jun.Soil-water and deformation characteristics of Nanyang expansive soil after wetting-drying cycles[J].Rock and Soil Mechanics,2015,36(Supp.1):115-119.
[8]ESTABRAGH A R,MOGHADAS M,JAVADI A A.Effect of different types of wetting fluids on the behaviour of expansive soil during wetting and drying[J].Soils and Foundations,2013,53(5):617-627.
[9]徐彬,殷宗泽,刘述丽.膨胀土强度影响因素与规律的试验研究[J].岩土力学,2011,32(1):44-50.XU Bin,YIN Zong-ze,LIU Shu-li.Experimental study of factors influencing expansive soil strength[J].Rock and Soil Mechanics,2011,32(1):44-50.
[10]孔令伟,陈建斌,郭爱国,等.大气作用下膨胀土边坡的现场响应试验研究[J].岩土工程学报,2007,29(7):1065-1073.KONG Ling-wei,CHEN Jian-bin,GUO Ai-guo,et al.Field response tests on expansive soil slopes under atmosphere[J].Chinese Journal of GeotechnicalEngineering,2007,29(7):1065-1073.
[11]李新明,孔令伟,郭爱国,等.基于工程包边法的膨胀土抗剪强度干湿循环效应试验研究[J].岩土力学,2014,35(3):675-682.LI Xin-ming,KONG Ling-wei,GUO Ai-guo,et al.Experimental research on shear strength of expansive soil under wetting-drying cycles based on wrapping method[J].Rock and Soil Mechanics,2014,35(3):675-682.
[12]NOWAMOOZ H,MASROURI F.Relationships between soil fabric and suction cycles in compacted swelling soils[J].Engineering Geology,2010,114:444-455.
[13]MIAO L C,LIU S Y,LAI Y M.Research of soil-water characteristics and shear strength features of Nanyang expansive soil[J].Engineering Geology,2002,65:261-267.
[14]KAMPALA A,HORPIBULSUK S,PRONGMANEE N.Influence of wet-dry cycles on compressive strength of calcium carbide residue–fly ash stabilized clay[J].Journal of Materials in Civil Engineering,2014,26(4):633-643.
[15]ALDAOOD A,BOUASKER M,AL-MUKHTAR M.Impact of wetting–drying cycles on the microstructure and mechanical properties of lime-stabilized gypseous soils[J].Engineering Geology,2014,174:11-21.
[16]RAYHANIA M H T,YANFULB E K,FAKHER A.Physical modeling of desiccation cracking in plastic soils[J].Engineering Geology,2008,97:25-31.
[17]RAYHANIA M H T,YANFULB E K,FAKHER A.Desiccation induced cracking and its effect on hydraulic conductivity of clayey soils from Iran[J].Canadian Geotechnical Journal,2007,44:276-283.
[18]张家俊,龚壁卫,胡波.干湿循环作用下膨胀土裂隙演化规律试验研究[J].岩土力学,2011,32(9):2729-2734.ZHANG Jia-jun,GONG Bi-wei,HU Bo.Study of evolution law of fissures of expansive clay under wetting and drying cycles[J].Rock and Soil Mechanics,2011,32(9):2729-2734.
[19]NOWAMOOZ H,JAHANGIR E,MASROURI F.Volume change behavior of a swelling soil compacted at different initial states[J].Engineering Geology,2013,153:25-34.
[20]杨和平,张锐,郑健龙.有荷条件下膨胀土的干湿胀缩变形及强度变化规律[J].岩土工程学报,2006,28(11):1936-1941.YANG He-ping,ZHANG Rui,ZHENG Jian-long.Variation of deformation and strength of expansive soil during cyclic wetting and drying under loading condition[J].Chinese Journal of Geotechnical Engineering,2006,28(11):1936-1941.
[21]杨和平,王兴正,肖杰.干湿循环效应对南宁外环膨胀土抗剪强度的影响[J].岩土工程学报,2014,36(5):949-954.YANG He-ping,WANG Xing-zheng,XIAO Jie.Influence of wetting-drying cycles on strength characteristics of Nanning expansive soils[J].Chinese Journal of Geotechnical Engineering,2014,36(5):949-954.
[22]肖杰,杨和平,王兴正,等.南宁外环膨胀土抗剪强度非线性特征及影响因素分析[J].中国公路学报,2014,27(10):1-8.XIAO Jie,YANG He-ping,WANG Xing-zheng.Analysis of nonlinear characteristics of shear strength of Nanning expansive soil and its influencing factors[J].Chinese Journal of Highway and Transport,2014,27(10):1-8.
[23]邓华锋,肖瑶,方景成,等.干湿循环作用下岸坡消落带土体抗剪强度劣化规律及其对岸坡稳定性影响研究[J].岩土力学,2017,38(9):2629-2638.DENG Hua-feng,XIAO Yao,FANG Jing-cheng,,et al.Shear strength degradation and slope stability of soils at hydro-fluctuation belt of river bank slope during drying-wetting cycle[J].Rock and Soil Mechanics,2017,38(9):2629-2638.
[24]中华人民共和国行业标准.SL237-1999土工试验规程[S].北京:中国水利水电出版社,1999.The Professional Standards Compilation Group of Peoples Republic of China.SL237-1999 Specification of soil test[S].Beijing:China Water Power Press,1999.
[25]孔纲强,刘璐,刘汉龙,等.玻璃砂透明土变形特性三轴试验研究[J].岩土工程学报,2013,35(6):1140-1146.KONG Gang-qiang,LIU Lu,LIU Han-long,et al.Triaxial tests on deformation characteristics of transparent glass sand[J].Chinese Journal of Geotechnical Engineering,2013,35(6):1140-1146.
[26]《工程地质手册》编委会.工程地质手册[M].北京:中国建筑工业出版社,2007.“Engineering Geology Handbook”Editorial Board.Handbook of engineering geology[M].Beijing:Chinese Building Industry Press,2007.
[27]李广信.高等土力学[M].北京:清华大学出版社,2004.LI Guang-xin.Advanced soil mechanics[M].Beijing:Tsinghua University Press,2004.
[28]叶为民,万敏,陈宝,等.干湿循环条件下高压实膨润土的微观结构特征[J].岩土工程学报,2011,33(8):1173-1177.YE Wei-min,WAN Min,CHEN Bao,et al.Micro-structural behaviors of densely compacted GMZ01bentonite under drying/wetting cycles[J].Chinese Journal of Geotechnical Engineering,2011,33(8):1173-1177.