湿干冻融耦合循环作用下膨胀土力学特性及损伤演化规律研究
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摘要
针对北疆高寒区膨胀土输水渠道破坏异常严重的问题,开展单向湿干及湿干冻融耦合作用下渠基膨胀土的三轴试验,探讨冻融过程对膨胀土力学特性及损伤演化规律的影响,获得不同循环次数下膨胀土的应力–应变关系、弹性模量、有效抗剪强度指标及其影响因素。结合损伤力学基础理论,引入可评价湿干与冻融过程耦合作用的损伤变量,探讨膨胀土强度和模量的损伤过程。试验结果表明:湿干及湿干冻融耦合循环作用对低围压(σ3=100kPa)试样的应力–应变曲线形态产生影响,应力–应变曲线形态差异性随围压的增加逐渐降低;对比不同试验条件下试样的弹性模量和有效抗剪强度指标可知,湿干冻融耦合循环中的冻融过程显著加剧了土体弹性模量和有效黏聚力的衰减,但对有效内摩擦角的影响有限;围压较高状态下试样的损伤以湿干过程作用为主,冻融过程对低围压试验下的损伤效果较明显。
Aiming at the serious damage of water supply canals in expensive soils in the high cold region of northern Xinjiang,the triaxial tests under the unidirectional action of wetting-drying and the cyclic action of coupling wetting-drying and freeze-thaw were performed to investigate the influences of freeze-thaw process on mechanical properties and damage evolution law of expensive soils. The stress-strain behavior,the elastic modulus and the effective shear strength index were obtained under different cycles and the influence factors were discussed. Based on the basic theory of damage mechanics,a damage variable was introduced to evaluate the coupling effect of wetting-drying and freeze-thaw processes,and the strength and modulus damage process were also discussed. The test results show that,under a low confining pressure(σ3 = 100 kPa),the stress-strain behaviors of samples are affected considerably by the cycle numbers and that the morphological difference of different stress-strain curves decreases with increasing the confining pressure. A comparison of the elastic modulus and the effective shear strength index of samples under different test conditions indicates that the freeze-thaw process in the coupling cycle of wetting-drying and freeze-thaw has significant influence on the attenuation of the elastic modulus and the effective cohesion but limited effect on the effective internal friction angle. The damage of soil under a high confining pressure is mainly caused by wetting-drying process,while the damage effect of freeze-thaw process under a low confining pressure is more obvious.
Aiming at the serious damage of water supply canals in expensive soils in the high cold region of northern Xinjiang,the triaxial tests under the unidirectional action of wetting-drying and the cyclic action of coupling wetting-drying and freeze-thaw were performed to investigate the influences of freeze-thaw process on mechanical properties and damage evolution law of expensive soils. The stress-strain behavior,the elastic modulus and the effective shear strength index were obtained under different cycles and the influence factors were discussed. Based on the basic theory of damage mechanics,a damage variable was introduced to evaluate the coupling effect of wetting-drying and freeze-thaw processes,and the strength and modulus damage process were also discussed. The test results show that,under a low confining pressure(σ3 = 100 kPa),the stress-strain behaviors of samples are affected considerably by the cycle numbers and that the morphological difference of different stress-strain curves decreases with increasing the confining pressure. A comparison of the elastic modulus and the effective shear strength index of samples under different test conditions indicates that the freeze-thaw process in the coupling cycle of wetting-drying and freeze-thaw has significant influence on the attenuation of the elastic modulus and the effective cohesion but limited effect on the effective internal friction angle. The damage of soil under a high confining pressure is mainly caused by wetting-drying process,while the damage effect of freeze-thaw process under a low confining pressure is more obvious.
引文
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[10]王大雁,马巍,常小晓,等.冻融循环作用对青藏黏土物理力学性质的影响[J].岩石力学与工程学报,2005,24(23):4 313-4 319.(WANG Dayan,MA Wei,CHANG Xiaoxiao,et al.Physico-mechanical properties changes of Qinghai-Tibet clay due to cyclic freezing and thawing[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(23):4 313-4 319.(in Chinese))
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[12]KONG L W,ZENG Z X,BAI W,et al.Engineering geological properties of weathered swelling mudstones and their effects on the landslides occurrence in the Yanji section of the Jilin-Hunchun high-speed railway[J].Bulletin of Engineering Geology and the Environment,2018,77(4):1 491-1 503.
[13]曾志雄,孔令伟,李晶晶,等.干湿-冻融循环下延吉膨胀岩的力学特性及其应力-应变归一化[J].岩土力学,2018,39(8):2 895-2 904.(ZENG Zhixiong,LI Xiongwei,LI Jingjing,et al.Mechanical properties and normalized stress-strain behaviour of Yanji swelling rock under wetting-drying-freezing-thawing cycles[J].Rock and Soil Mechanics,2018,39(8):2 895-2 904.(in Chinese))
[14]LI G Y,WANG F,MA W,et al.Variations in strength and deformation of compacted loess exposed to wetting-drying and freeze-thaw cycles[J].Cold Regions Science and Technology,2018,151:159-167.
[15]中华人民共和国行业标准编写组.SL 237-1999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 People′s Republic of China.SL 237-1999Specification of soil test[S].Beijing:China Water Power Press,1999.(in Chinese))
[16]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.(YANGHeping,WANG Xingzheng,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.(in Chinese))
[17]ALDAOOD A,BOUASKER M,AL-MUKHTAR M.Effect of water during freeze-thaw cycles on the performance and durability of lime-treated gypseous soil[J].Cold Regions Science and Technology,2016,123:155-163.
[18]LEE W,BOHRA N C,ALTSCHAEFFL A G,et al.Resilient modulus of cohesive soils[J].Journal of Geotechnical and Geoenvironmental Engineering,1997,123(2):131-136.
[19]QI J L,VERMEER P A,CHENG G.A review of the influence of freeze-thaw cycles on soil geotechnical properties[J].Permafrost and Periglacial Processes,2006,17:245-252.
[20]卢再华,陈正汉,蒲毅彬.膨胀土干湿循环胀缩裂隙演化的CT试验研究[J].岩土力学,2002,23(4):417-422.(LU Zaihua,CHENZhenghan,PU Yibin.A CT study on the crack evolution of expanisve soil during drying and wetting cycles[J].Rock and Soil Mechanics,2002,23(4):417-422.(in Chinese))
[21]吴安杰,邓建华,顾乡,等.冻融循环作用下泥质白云岩力学特性及损伤演化规律研究[J].岩土力学,2014,35(11):3 065-3 072.(WU Anjie,DENG Jianhua,GU Xiang,et al.Research on mechanical properties and damage evolution law of argillaceous dolomite under freeze-thaw cycles[J].Rock and Soil Mechanics,2014,35(11):3 065-3 072.(in Chinese))
[22]LEMAITRE J.A course on damage mechanics[M].Berlin:SpringerVerlag,1996:135-156.
[23]张全胜,杨更社,任建喜.岩石损伤变量及本构方程的新探讨[J].岩石力学与工程学报,2003,22(1):30-34.(ZHANG Quansheng,YANG Gengshe,REN Jianxi.New study of damage variable and constitutive equation of rock[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(1):30-34.(in Chinese))
[24]TANG L,CONG S,LING X,et al.A unified formulation of stress-strain relations considering micro-damage for expansive soils exposed to freeze-thaw cycles[J].Cold Regions Science and Technology,2018,153(9):164-171.
[25]刘文化,杨庆,孙秀丽,等.干湿循环条件下干燥应力历史对粉质黏土饱和力学特性的影响[J].水利学报,2017,48(2):203-209.(LIU Wenhua,YANG Qing,SUN Xiuli,et al.Influence of drying stress history on the mechanical behaviors of silty clay under saturated condition[J].Journal of Hydraulic Engineering,2017,48(2):203-209.(in Chinese))
[26]AUBERT J E,GASC-BARBIER M.Hardening of clayey soil blocks during freezing and thawing cycles[J].Applied Clay Science,2012,65-66:1-5.
[27]张家俊,龚壁卫,胡波,等.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):2 729-2 734.(ZHANGJiajun,GONG Biwei,HU Bo,et al.Study of evolution law of fissures of expansive clay under wetting and drying cycles[J].Rock and Soil Mechanics,2011,32(9):2 729-2 734.(in Chinese))
[28]郑郧,马巍,邴慧.冻融循环对土结构性影响的试验研究及影响机制分析[J].岩土力学,2015,36(5):1 282-1 288.(ZHENGYun,MA Wei,BING Hui.Impact of freezing and thawing cycles on structure of soils and its mechanism analysis by laboratory testing[J].Rock and Soil Mechanics,2015,36(5):1 282-1 288.(in Chinese))
[29]冯德成,林波,张锋,等.冻融作用对土的工程性质影响的研究进展[J].中国科学:技术科学,2017,47(2):111-127.(FENGDecheng,LIN Bo,ZHANG Feng,et al.A review of freeze-thaw effects on soil geotechnical properties[J].Scientia Sinica Techologica,2017,47(2):111-127.(in Chinese))
[30]蔡正银,朱洵,黄英豪,等.冻融过程对膨胀土裂隙演化特征的影响[J].岩土力学,待刊.(CAI Zhengyin,ZHU Xun,HUANGYinghao,et al.Influences of freeze-thaw process on evolution characteristics of fissures in expensive soils[J].Rock and Soil Mechanics,to be pressed.(in Chinese))
[2]程展林,龚壁卫.膨胀土边坡[M].北京:科学出版社,2015:145-147.(CHENG Zhanlin,GONG Biwei.Expansive soil slope[M].Beijing:Science Press,2015:145-147.(in Chinese))
[3]李雄威,孔令伟,郭爱国.气候影响下膨胀土工程性质的原位响应特征试验研究[J].岩土力学,2009,30(7):2 069-2 074.(LIXiongwei,KONG Lingwei,GUO Aiguo.Field response characteristic test of expansive soil engineering behavior under effect of atmosphere[J].Rock and Soil Mechanics,2009,30(7):2 069-2 074.(in Chinese))
[4]雷雨,龙爱华,邓铭江,等.1926-2009年额尔齐斯河流域中游地区气候变化及其对水资源的影响分析[J].冰川冻土,2012,34(4):912-919.(LEI Yu,LONG Aihua,DENG Mingjiang,et al.Analyses of the climate change and its impact on water resources in the middle reaches of Irtysh River during 1926-2009[J].Journal of Glaciology and Geocryology,2012,34(4):912-919.(in Chinese))
[5]蔡正银,黄英豪.咸寒区渠道冻害评估与处治技术[M].北京:科学出版社,2015:23-27.(CAI Zhengyin,HUANG Yinghao.Evaluation and treatment technology of frost damage in canals in saline and cold regions[M].Beijing:Science Press,2015:23-27.(in Chinese))
[6]谭罗荣,孔令伟.特殊岩土工程土质学[M].北京:科学出版社,2006:56-60.(TAN Luorong,KONG Lingwei.Engineering behavior of special rock and soil[M].Beijing:Science Press,2006:56-60.(in Chinese))
[7]吕海波,曾召田,赵艳林,等.膨胀土强度干湿循环试验研究[J].岩土力学,2009,30(12):3 797-3 802.(LV Haibo,ZENG Zhaotian,ZHAO Yanlin,et al.Experimental studies of strength of expansive soil in drying and wetting cycle[J].Rock and Soil Mechanics,2009,30(12):3 797-3 802.(in Chinese))
[8]CUI Z D,HE P P,YANG W H.Mechanical properties of a silty clay subjected to freezing-thawing[J].Cold Regions Science and Technology,2014,98:26-34.
[9]HOTINEANU A,BOUASKER M,ALDAOOD A,et al.Effect of freeze-thaw cycling on the mechanical properties of lime-stabilized expansive clays[J].Cold Regions Science and Technology,2015,119:151-157.
[10]王大雁,马巍,常小晓,等.冻融循环作用对青藏黏土物理力学性质的影响[J].岩石力学与工程学报,2005,24(23):4 313-4 319.(WANG Dayan,MA Wei,CHANG Xiaoxiao,et al.Physico-mechanical properties changes of Qinghai-Tibet clay due to cyclic freezing and thawing[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(23):4 313-4 319.(in Chinese))
[11]TANG L,CONG S,GENG L,et al.The effect of freeze-thaw cycling on the mechanical properties of expansive soils[J].Cold Regions Science and Technology,2018,145:197-207.
[12]KONG L W,ZENG Z X,BAI W,et al.Engineering geological properties of weathered swelling mudstones and their effects on the landslides occurrence in the Yanji section of the Jilin-Hunchun high-speed railway[J].Bulletin of Engineering Geology and the Environment,2018,77(4):1 491-1 503.
[13]曾志雄,孔令伟,李晶晶,等.干湿-冻融循环下延吉膨胀岩的力学特性及其应力-应变归一化[J].岩土力学,2018,39(8):2 895-2 904.(ZENG Zhixiong,LI Xiongwei,LI Jingjing,et al.Mechanical properties and normalized stress-strain behaviour of Yanji swelling rock under wetting-drying-freezing-thawing cycles[J].Rock and Soil Mechanics,2018,39(8):2 895-2 904.(in Chinese))
[14]LI G Y,WANG F,MA W,et al.Variations in strength and deformation of compacted loess exposed to wetting-drying and freeze-thaw cycles[J].Cold Regions Science and Technology,2018,151:159-167.
[15]中华人民共和国行业标准编写组.SL 237-1999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 People′s Republic of China.SL 237-1999Specification of soil test[S].Beijing:China Water Power Press,1999.(in Chinese))
[16]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.(YANGHeping,WANG Xingzheng,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.(in Chinese))
[17]ALDAOOD A,BOUASKER M,AL-MUKHTAR M.Effect of water during freeze-thaw cycles on the performance and durability of lime-treated gypseous soil[J].Cold Regions Science and Technology,2016,123:155-163.
[18]LEE W,BOHRA N C,ALTSCHAEFFL A G,et al.Resilient modulus of cohesive soils[J].Journal of Geotechnical and Geoenvironmental Engineering,1997,123(2):131-136.
[19]QI J L,VERMEER P A,CHENG G.A review of the influence of freeze-thaw cycles on soil geotechnical properties[J].Permafrost and Periglacial Processes,2006,17:245-252.
[20]卢再华,陈正汉,蒲毅彬.膨胀土干湿循环胀缩裂隙演化的CT试验研究[J].岩土力学,2002,23(4):417-422.(LU Zaihua,CHENZhenghan,PU Yibin.A CT study on the crack evolution of expanisve soil during drying and wetting cycles[J].Rock and Soil Mechanics,2002,23(4):417-422.(in Chinese))
[21]吴安杰,邓建华,顾乡,等.冻融循环作用下泥质白云岩力学特性及损伤演化规律研究[J].岩土力学,2014,35(11):3 065-3 072.(WU Anjie,DENG Jianhua,GU Xiang,et al.Research on mechanical properties and damage evolution law of argillaceous dolomite under freeze-thaw cycles[J].Rock and Soil Mechanics,2014,35(11):3 065-3 072.(in Chinese))
[22]LEMAITRE J.A course on damage mechanics[M].Berlin:SpringerVerlag,1996:135-156.
[23]张全胜,杨更社,任建喜.岩石损伤变量及本构方程的新探讨[J].岩石力学与工程学报,2003,22(1):30-34.(ZHANG Quansheng,YANG Gengshe,REN Jianxi.New study of damage variable and constitutive equation of rock[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(1):30-34.(in Chinese))
[24]TANG L,CONG S,LING X,et al.A unified formulation of stress-strain relations considering micro-damage for expansive soils exposed to freeze-thaw cycles[J].Cold Regions Science and Technology,2018,153(9):164-171.
[25]刘文化,杨庆,孙秀丽,等.干湿循环条件下干燥应力历史对粉质黏土饱和力学特性的影响[J].水利学报,2017,48(2):203-209.(LIU Wenhua,YANG Qing,SUN Xiuli,et al.Influence of drying stress history on the mechanical behaviors of silty clay under saturated condition[J].Journal of Hydraulic Engineering,2017,48(2):203-209.(in Chinese))
[26]AUBERT J E,GASC-BARBIER M.Hardening of clayey soil blocks during freezing and thawing cycles[J].Applied Clay Science,2012,65-66:1-5.
[27]张家俊,龚壁卫,胡波,等.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):2 729-2 734.(ZHANGJiajun,GONG Biwei,HU Bo,et al.Study of evolution law of fissures of expansive clay under wetting and drying cycles[J].Rock and Soil Mechanics,2011,32(9):2 729-2 734.(in Chinese))
[28]郑郧,马巍,邴慧.冻融循环对土结构性影响的试验研究及影响机制分析[J].岩土力学,2015,36(5):1 282-1 288.(ZHENGYun,MA Wei,BING Hui.Impact of freezing and thawing cycles on structure of soils and its mechanism analysis by laboratory testing[J].Rock and Soil Mechanics,2015,36(5):1 282-1 288.(in Chinese))
[29]冯德成,林波,张锋,等.冻融作用对土的工程性质影响的研究进展[J].中国科学:技术科学,2017,47(2):111-127.(FENGDecheng,LIN Bo,ZHANG Feng,et al.A review of freeze-thaw effects on soil geotechnical properties[J].Scientia Sinica Techologica,2017,47(2):111-127.(in Chinese))
[30]蔡正银,朱洵,黄英豪,等.冻融过程对膨胀土裂隙演化特征的影响[J].岩土力学,待刊.(CAI Zhengyin,ZHU Xun,HUANGYinghao,et al.Influences of freeze-thaw process on evolution characteristics of fissures in expensive soils[J].Rock and Soil Mechanics,to be pressed.(in Chinese))