易溶盐含量对原状非饱和伊犁黄土强度的影响
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摘要
【目的】研究易溶盐含量和基质吸力对非饱和伊犁黄土强度的影响规律,为伊犁黄土地区工程建设提供参考。【方法】利用水膜转移法将配置好的盐溶液加入原状伊犁黄土土样中,制成3种不同易溶盐含量(5,14,26g/kg)土样,采用非饱和土三轴仪进行3种不同易溶盐含量下控制净围压(100,200,300kPa)和基质吸力(50,100,150kPa)的三轴固结排水剪切试验,测定并分析土样强度的变化规律。【结果】非饱和伊犁黄土的偏应力-轴向应变关系曲线均为硬化型;在相同净围压和基质吸力作用下,易溶盐含量14g/kg非饱和伊犁黄土的强度最高。非饱和伊犁黄土的有效黏聚力随基质吸力的增大而增大,随易溶盐含量的增加呈先增大后减小的趋势,易溶盐含量5,14,26g/kg的非饱和伊犁黄土在50,100,150kPa 3种基质吸力下的有效黏聚力分别为21.30,31.50,40.50kPa,33.10,44.80,58.10kPa和19.70,28.30,36.70kPa。有效内摩擦角随基质吸力的增大基本不变;随易溶盐含量的增加呈先减小后增大的趋势,分别为23.33°,22.35°,23.76°。随着易溶盐含量的增加吸力摩擦角分别为10.76°,14.04°,9.65°,呈先增大后减小的趋势,且增减速率相同。【结论】基于Barcelona模型建立的非饱和伊犁黄土弹塑性模型的剪切屈服面方程,具有可以考虑易溶盐含量和基质吸力两个因素耦合变化的优点,适用于易溶盐含量较高的伊犁黄土。
【Objective】This study investigated the influence of soluble salt content and matrix suction on strength of unsaturated Ili loess to provide reference for construction in the Ili loess areas.【Method】The water film transfer method was used to add salt solution to original Ili loess,and three types of soil samples with soluble salt contents of 5,14 and 26 g/kg were prepared.Unsaturated soil triaxial apparatus was used to determine and analyze the change of soil strength by triaxial consolidation drainage shear test at different net confining pressures(100,200 and 300 kPa)and matrix suctions(50,100 and 150 kPa).【Result】The partial stress-axial strain curves of unsaturated Ili loess were hardened.Under same net confining pressure and matrix suction circumstance,the strength of unsaturated Ili loess with 14 g/kg soluble salt content was the strongest.The effective cohesion of unsaturated Ili loess increased with the suction of matrices,while increased first and then decreased with the increase of soluble salt content.The effective cohesions of 5,14 and 26 g/kg unsaturated Ili loess under matric suctions of 50,100 and 150 kPa were21.30,31.50 and 40.50 kPa,33.10,44.80 and 58.10 kPa,as well as 19.70,28.30 and 36.70 kPa,respectively.The effective internal friction angle remained same with the increase of the matrix suction,while it increased with the increase of soluble salt content with values of 23.33°,22.35°and 23.76°,respectively.The suction friction angles were 10.76°,14.04°and 9.65°as the increase of soluble salt content,indicating increase first followed by decrease with same rate.【Conclusion】Based on the Barcelona model,a shear yield surface equation of the elasto-plastic model of unsaturated Ili loess was established.It has the advantage of coupling changes of easily soluble salt content and suction,and is very suitable for Ili loess with high soluble salt content.
【Objective】This study investigated the influence of soluble salt content and matrix suction on strength of unsaturated Ili loess to provide reference for construction in the Ili loess areas.【Method】The water film transfer method was used to add salt solution to original Ili loess,and three types of soil samples with soluble salt contents of 5,14 and 26 g/kg were prepared.Unsaturated soil triaxial apparatus was used to determine and analyze the change of soil strength by triaxial consolidation drainage shear test at different net confining pressures(100,200 and 300 kPa)and matrix suctions(50,100 and 150 kPa).【Result】The partial stress-axial strain curves of unsaturated Ili loess were hardened.Under same net confining pressure and matrix suction circumstance,the strength of unsaturated Ili loess with 14 g/kg soluble salt content was the strongest.The effective cohesion of unsaturated Ili loess increased with the suction of matrices,while increased first and then decreased with the increase of soluble salt content.The effective cohesions of 5,14 and 26 g/kg unsaturated Ili loess under matric suctions of 50,100 and 150 kPa were21.30,31.50 and 40.50 kPa,33.10,44.80 and 58.10 kPa,as well as 19.70,28.30 and 36.70 kPa,respectively.The effective internal friction angle remained same with the increase of the matrix suction,while it increased with the increase of soluble salt content with values of 23.33°,22.35°and 23.76°,respectively.The suction friction angles were 10.76°,14.04°and 9.65°as the increase of soluble salt content,indicating increase first followed by decrease with same rate.【Conclusion】Based on the Barcelona model,a shear yield surface equation of the elasto-plastic model of unsaturated Ili loess was established.It has the advantage of coupling changes of easily soluble salt content and suction,and is very suitable for Ili loess with high soluble salt content.
引文
[1]张爱军,邢义川,胡新丽,等.伊犁黄土强烈自重湿陷性的影响因素分析[J].岩土工程学报,2016,38(S2):117-122.Zhang A J,Xing Y C,Hu X L,et al.Influence factors of strong self-weight collapsibility of Ili loess[J].Chinese Journal of Geotechnical Engineering,2016,38(S2):177-122.
[2]Sayles F H,Carbee D L.Strength of frozen silt as a function of ice content and dry unit weight[J].Engineering Geology,1981,18:55-66.
[3]Roman L T.Effect of chemical composition of soils on the strength and deformability of frozen saline soils[J].Soil Mechanics and Foundation Engineering,1994,31(6):205-210.
[4]孙德安,张谨绎,宋国森.氯盐渍土土-水特征曲线的试验研究[J].岩土力学,2013,34(4):955-960.Sun D A,Zhang J Y,Song G S.Experimental study of soil-water characteristic curve of chlorine soil[J].Rock and Mechanics,2013,34(4):955-960.
[5]柴寿喜,王晓燕,王沛,等.含盐量对石灰固化滨海盐渍土微结构参数的影响[J].岩土力学,2009,30(2):305-310.Cai S X,Wang X Y,Wang P,et al.Effect of salt content on microstructure parameters of lime-hardened coastal saline soil[J].Rock and Soil Mechanics,2009,30(2):305-310.
[6]柴寿喜,杨宝珠,王晓燕,等.含盐量对石灰固化滨海盐渍土力学强度影响试验研究[J].岩土力学,2008,29(7):1769-1772,1777.Cai S X,Yang B Z,Wang X Y.et al.Effect of salt content on mechanical strength of lime-hardened coastal saline soil[J].Rock and Soil Mechanics,2008,29(7):1769-1772,1777.
[7]陈炜韬,李姝,王鹰.含盐量、含盐类别对盐渍土抗剪强度的影响[J].铁道建筑技术,2005(6):54-56,73.Chen W T,Li S,Wang Y.Effect of salinity and salt contents on shear strength of saline soil[J].Railway Construction Technology,2005(6):54-56,73.
[8]郭菊彬,张昆,王鹰.盐渍土抗剪强度与含水量、含盐量及干密度关系探讨[J].工程勘察,2006(1):12-14.Guo J B,Zhang K,Wang Y.Relationship between shear strength,moisture content,salt content and dry density of saline soil[J].Geotechnical Investigation&Surveying,2006(1):12-14.
[9]张飞,胡小庆,刘亚薇,等.含盐量对硫酸盐渍土抗剪强度影响试验研究[J].铁道建筑,2014(6):162-164.Zhang F,Hu X Q,Liu Y W,et al.Experimental study on effect of salt content on shear strength of sulfate soil[J].Railway Engineering,2014(6):12-14.
[10]孙立强,路江鑫,李恒,等.含水率和含盐量对人工冻土强度特性影响的试验研究[J].岩土工程学报,2015,37(S2):27-31.Sun L Q,Lu J X,Li H,et al.Influence of water and salt contents on strength of artificially frozen soils[J].Chinese Journal of Geotechnical Engineering,2015,37(S2):27-31.
[11]蔡正银,吴志强,黄英豪,等.含水率和含盐量对冻土无侧限抗压强度影响的试验研究[J].岩土工程学报,2014,36(9):1580-1586.Cai Z Y,Wu Z Q,Huang Y H,et al.Influence of water and salt contents on strength of frozen soils[J].Chinese Journal of Geotechnical Engineering,2014,36(9):1580-1586.
[12]储诚富,刘松玉,邓永锋,等.含盐量对水泥土强度影响的室内试验研究[J].工程地质学报,2007,15(1):139-143.Chu C F,Liu S Y,Deng Y F,et al.The threshold of salt contentson on strength of cement-mixed clays a finding of laboratory tests[J].Journal of Engineering Geology,2007,15(1):139-143.
[13]米海珍,王月礼,赵景华,等.含盐量对水泥灰土强度特性的影响[J].建筑科学与工程学报,2013,30(3):91-95.Mi H Z,Wang Y L,Zhao J H,et al.Effects of salt content on strength characterisitic of cement lime soil[J].Journal of Architecture and Civil Engineering,2013,30(3):91-95.
[14]邴慧,武俊杰,邓津.黄土状盐渍土洗盐前后物理力学性质的变化[J].冰川冻土,2011,33(4):796-800.Bing H,Wu J J,Deng J.Changes of physical and mechanical properties of loess salty soil before and after washing salt[J].Journal of Glaciology and Geocryology,2011,33(4):796-800.
[15]Zhang F Y,Wang G H,Kamai T,et al.Undrained shear behavior of loess saturated with different concentrations of sodium chloride solution[J].Engineerin Geology,2013,155(1):69-79.
[16]张宁宁,骆亚生.易溶盐对黄土强度特性影响[J].人民黄河,2014,36(8):103-105.Zhang N N,Luo Y S.Influence of soluble on the strength characteristics of loess[J].Yellow River,2014,36(8):103-105.
[17]李冬阳,赵竞哲.易溶盐浓度对黄土抗剪强度影响研究[J].科技创新与应用,2016(25):104-106.Li D Y,Zhao J Z.Effect of ease salt concentration on shear strength of loess[J].Technology Innovation and Application,2016(25):104-106.
[18]闫亚景,文宝萍,黄志全.可溶盐对兰州非饱和重塑黄土抗剪强度的影响[J].岩土力学,2017,38(10):2881-2887.Yan Y J,Wen B P,Huang Z Q.Effect of soluble salts on shear strength of unsaturated remoulded loess in Lanzhou city[J].Rock and Soil Mechanics,2017,38(10):2881-2887.
[19]南京水利科学研究院.SL 237-1999土工试验规程[S].北京:中国水利水电出版社,1999.Nanjing Hydraulic Research Institute.SL 237-1999specification of soil test[S].Beijing:China Water&Power Press,1999.
[20]Fredlund D G,Rahardio H.Soil mechanics for unsaturated soils[M].New York:John Wiley,1993.
[21]Alonso E E,Gens A,Josa A.A constitutive modle for partially saturated soils[J].Geotechnique,1990,40(3):405-430.
[22]Alonso E E,Vaunat J,Gens A.Modelling the mechanical behavior of expansive clays[J].Engineering Geology,1999,54(1/2):173-183.
[2]Sayles F H,Carbee D L.Strength of frozen silt as a function of ice content and dry unit weight[J].Engineering Geology,1981,18:55-66.
[3]Roman L T.Effect of chemical composition of soils on the strength and deformability of frozen saline soils[J].Soil Mechanics and Foundation Engineering,1994,31(6):205-210.
[4]孙德安,张谨绎,宋国森.氯盐渍土土-水特征曲线的试验研究[J].岩土力学,2013,34(4):955-960.Sun D A,Zhang J Y,Song G S.Experimental study of soil-water characteristic curve of chlorine soil[J].Rock and Mechanics,2013,34(4):955-960.
[5]柴寿喜,王晓燕,王沛,等.含盐量对石灰固化滨海盐渍土微结构参数的影响[J].岩土力学,2009,30(2):305-310.Cai S X,Wang X Y,Wang P,et al.Effect of salt content on microstructure parameters of lime-hardened coastal saline soil[J].Rock and Soil Mechanics,2009,30(2):305-310.
[6]柴寿喜,杨宝珠,王晓燕,等.含盐量对石灰固化滨海盐渍土力学强度影响试验研究[J].岩土力学,2008,29(7):1769-1772,1777.Cai S X,Yang B Z,Wang X Y.et al.Effect of salt content on mechanical strength of lime-hardened coastal saline soil[J].Rock and Soil Mechanics,2008,29(7):1769-1772,1777.
[7]陈炜韬,李姝,王鹰.含盐量、含盐类别对盐渍土抗剪强度的影响[J].铁道建筑技术,2005(6):54-56,73.Chen W T,Li S,Wang Y.Effect of salinity and salt contents on shear strength of saline soil[J].Railway Construction Technology,2005(6):54-56,73.
[8]郭菊彬,张昆,王鹰.盐渍土抗剪强度与含水量、含盐量及干密度关系探讨[J].工程勘察,2006(1):12-14.Guo J B,Zhang K,Wang Y.Relationship between shear strength,moisture content,salt content and dry density of saline soil[J].Geotechnical Investigation&Surveying,2006(1):12-14.
[9]张飞,胡小庆,刘亚薇,等.含盐量对硫酸盐渍土抗剪强度影响试验研究[J].铁道建筑,2014(6):162-164.Zhang F,Hu X Q,Liu Y W,et al.Experimental study on effect of salt content on shear strength of sulfate soil[J].Railway Engineering,2014(6):12-14.
[10]孙立强,路江鑫,李恒,等.含水率和含盐量对人工冻土强度特性影响的试验研究[J].岩土工程学报,2015,37(S2):27-31.Sun L Q,Lu J X,Li H,et al.Influence of water and salt contents on strength of artificially frozen soils[J].Chinese Journal of Geotechnical Engineering,2015,37(S2):27-31.
[11]蔡正银,吴志强,黄英豪,等.含水率和含盐量对冻土无侧限抗压强度影响的试验研究[J].岩土工程学报,2014,36(9):1580-1586.Cai Z Y,Wu Z Q,Huang Y H,et al.Influence of water and salt contents on strength of frozen soils[J].Chinese Journal of Geotechnical Engineering,2014,36(9):1580-1586.
[12]储诚富,刘松玉,邓永锋,等.含盐量对水泥土强度影响的室内试验研究[J].工程地质学报,2007,15(1):139-143.Chu C F,Liu S Y,Deng Y F,et al.The threshold of salt contentson on strength of cement-mixed clays a finding of laboratory tests[J].Journal of Engineering Geology,2007,15(1):139-143.
[13]米海珍,王月礼,赵景华,等.含盐量对水泥灰土强度特性的影响[J].建筑科学与工程学报,2013,30(3):91-95.Mi H Z,Wang Y L,Zhao J H,et al.Effects of salt content on strength characterisitic of cement lime soil[J].Journal of Architecture and Civil Engineering,2013,30(3):91-95.
[14]邴慧,武俊杰,邓津.黄土状盐渍土洗盐前后物理力学性质的变化[J].冰川冻土,2011,33(4):796-800.Bing H,Wu J J,Deng J.Changes of physical and mechanical properties of loess salty soil before and after washing salt[J].Journal of Glaciology and Geocryology,2011,33(4):796-800.
[15]Zhang F Y,Wang G H,Kamai T,et al.Undrained shear behavior of loess saturated with different concentrations of sodium chloride solution[J].Engineerin Geology,2013,155(1):69-79.
[16]张宁宁,骆亚生.易溶盐对黄土强度特性影响[J].人民黄河,2014,36(8):103-105.Zhang N N,Luo Y S.Influence of soluble on the strength characteristics of loess[J].Yellow River,2014,36(8):103-105.
[17]李冬阳,赵竞哲.易溶盐浓度对黄土抗剪强度影响研究[J].科技创新与应用,2016(25):104-106.Li D Y,Zhao J Z.Effect of ease salt concentration on shear strength of loess[J].Technology Innovation and Application,2016(25):104-106.
[18]闫亚景,文宝萍,黄志全.可溶盐对兰州非饱和重塑黄土抗剪强度的影响[J].岩土力学,2017,38(10):2881-2887.Yan Y J,Wen B P,Huang Z Q.Effect of soluble salts on shear strength of unsaturated remoulded loess in Lanzhou city[J].Rock and Soil Mechanics,2017,38(10):2881-2887.
[19]南京水利科学研究院.SL 237-1999土工试验规程[S].北京:中国水利水电出版社,1999.Nanjing Hydraulic Research Institute.SL 237-1999specification of soil test[S].Beijing:China Water&Power Press,1999.
[20]Fredlund D G,Rahardio H.Soil mechanics for unsaturated soils[M].New York:John Wiley,1993.
[21]Alonso E E,Gens A,Josa A.A constitutive modle for partially saturated soils[J].Geotechnique,1990,40(3):405-430.
[22]Alonso E E,Vaunat J,Gens A.Modelling the mechanical behavior of expansive clays[J].Engineering Geology,1999,54(1/2):173-183.