聚苯乙烯(EPS)颗粒混合轻量土的动强度参数研究
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摘要
【目的】探讨水泥用量、聚苯乙烯(Expanded Polystyrene,EPS)颗粒用量和振动次数对EPS颗粒混合轻量土动强度参数的影响,分析EPS颗粒混合轻量土的动强度参数特性,为EPS颗粒混合轻量土的推广使用提供参考。【方法】通过室内动三轴试验,以黄土作为原料土,在EPS颗粒用量为1.4,3.1,5.4,8.6,13.1,20.1 g/kg,水泥用量为100,150,200 g/kg的条件下制备不同原料用量EPS颗粒混合轻量土,设定固结应力为50,100,150和200 kPa,固结应力比K_c=1.0,振动次数为10,20,30,40,50,60,70,80,90和100,通过莫尔应力圆计算土体的总应力参数,采用5.0%压应变作为破坏标准选取相应的动强度,并分析水泥用量、EPS颗粒用量及振动次数对EPS颗粒混合轻量土动强度参数的影响。【结果】当固结应力比K_c=1.0时,不同原料用量EPS颗粒混合轻量土的动强度包络线均不经过原点,且在剪应力轴存在一定的截距。当水泥用量一定时,随着EPS颗粒用量的增大,EPS颗粒混合轻量土的动黏聚力和动内摩擦角均有所减小,其中当振动次数为20,EPS颗粒含量由1.4 g/kg增大到20.1 g/kg时,动黏聚力减少43.39%,动内摩擦角减少并趋于0。当EPS颗粒用量一定时,随着水泥用量的增大,EPS颗粒混合轻量土的动黏聚力和动内摩擦角均呈增大趋势,其中当振动次数为20,水泥用量由100 g/kg增大到200 g/kg时,动黏聚力增大了54.07%,动内摩擦角增大了140.95%。【结论】水泥用量和EPS颗粒用量对EPS颗粒混合轻量土的动强度参数均有较大的影响,振动次数对动黏聚力影响较大而对动内摩擦角影响甚微,在分析土体稳定性时应充分考虑以上因素的影响。
【Objective】 The influence of cement content,expanded polystyrene(EPS) content and cyclic number on dynamic strength parameters of light weight soil mixed with EPS beads was studied to provide reference for using EPS beads in geotechnical engineering.【Method】 The dynamic triaxial test was conducted using the loess as raw soil.The mixed light weight soil was prepared with EPS beads contents of 1.4,3.1,5.4,8.6,13.1,20.1 g/kg and cement contents of 100,150,200 g/kg.The confining pressures were set to 50,100,150 and 200 kPa,the consolidation stress ratio(K_c) was 1.0,the cyclic numbers were 10,20,30,40,50,60,70,80,90 and 100, and 5.0% compressive strain was chosen as the failure criterion.The total stress parameters of soil were calculated by Mohr's Circle and the influencing factors were analyzed.【Result】 When the consolidation stress ratio was 1.0,the dynamic strength envelopes of light weight soil mixed with EPS beads under different ratios did not pass through the origin and had intercepts at the shear stress axis.When the cement content was constant,the dynamic cohesion and dynamic internal friction angle decreased with the increase of EPS content.When the cyclic number was 20,the EPS content increased from 1.4 g/kg to 20.1 g/kg,the dynamic cohesion decreased by 43.39% and the dynamic internal friction angle decreased to 0.When EPS content was constant,with the increase of cement content,the dynamic cohesion and dynamic internal friction angle improved. With the cyclic number of 20,the cement content increased from 100 g/kg to 200 g/kg,the dynamic cohesion increased by 54.07%,and the dynamic internal friction angle increased by 140.95%.【Conclusion】 Both the cement content and EPS content had great influence on the dynamic strength parameters of light weight soil mixed with EPS beads.The cyclic number had large effect on the dynamic cohesion but insignificant effect on the dynamic friction angle.In the analysis of soil stability,above factors should be fully considered.
【Objective】 The influence of cement content,expanded polystyrene(EPS) content and cyclic number on dynamic strength parameters of light weight soil mixed with EPS beads was studied to provide reference for using EPS beads in geotechnical engineering.【Method】 The dynamic triaxial test was conducted using the loess as raw soil.The mixed light weight soil was prepared with EPS beads contents of 1.4,3.1,5.4,8.6,13.1,20.1 g/kg and cement contents of 100,150,200 g/kg.The confining pressures were set to 50,100,150 and 200 kPa,the consolidation stress ratio(K_c) was 1.0,the cyclic numbers were 10,20,30,40,50,60,70,80,90 and 100, and 5.0% compressive strain was chosen as the failure criterion.The total stress parameters of soil were calculated by Mohr's Circle and the influencing factors were analyzed.【Result】 When the consolidation stress ratio was 1.0,the dynamic strength envelopes of light weight soil mixed with EPS beads under different ratios did not pass through the origin and had intercepts at the shear stress axis.When the cement content was constant,the dynamic cohesion and dynamic internal friction angle decreased with the increase of EPS content.When the cyclic number was 20,the EPS content increased from 1.4 g/kg to 20.1 g/kg,the dynamic cohesion decreased by 43.39% and the dynamic internal friction angle decreased to 0.When EPS content was constant,with the increase of cement content,the dynamic cohesion and dynamic internal friction angle improved. With the cyclic number of 20,the cement content increased from 100 g/kg to 200 g/kg,the dynamic cohesion increased by 54.07%,and the dynamic internal friction angle increased by 140.95%.【Conclusion】 Both the cement content and EPS content had great influence on the dynamic strength parameters of light weight soil mixed with EPS beads.The cyclic number had large effect on the dynamic cohesion but insignificant effect on the dynamic friction angle.In the analysis of soil stability,above factors should be fully considered.
引文
[1]汤峻,朱伟,李明东,等.砂土EPS颗粒混和轻质土的物理力学特性[J].岩土力学,2007,28(5):1045-1049.Tang J,Zhu W,Li M D,et al.Physico-mechanical properties of sand EPS beads-mixed lightweight soil[J].Rock and Soil Mechanics,2007,28(5):1045-1049.
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[5]侯天顺,徐光黎.发泡颗粒混合轻量土抗剪强度特性试验研究[J].中国矿业大学学报,2010,39(4):534-540.Hou T S,Xu G L.Experimental study on the shear strength characteristics of foamed particle light weight soil[J].Journal of China University of Mining&Technology,2010,39(4):534-540.
[6]侯天顺.轻量土击实模型与工程特性[J].岩土工程学报,2014,36(11):2127-2135.Hou T S.Model for compaction density and engineering properties of light weight soil[J].Chinese Journal of Geotechnical Engineerding,2014,36(11):2127-2135.
[7]朱伟,姬凤玲,李明东,等.轻质土密度、强度与材料组成的关系研究[J].岩土力学,2007,28(7):1411-1414.Zhu W,Ji F L,Li M D,et al.Relationships among density,strength and materials of lightweight treated soil[J].Rock and Soil Mechanics,2007,28(7):1411-1414.
[8]Yasuhara K.Recent Japanese experiences with lightweight geomaterials[C]//Proceeding of the International Workshop on Lightweight Geo-Materials.Tokyo:Japanese Geitechnical Society,2002:35-60.
[9]Kojima K,Maruoka M.Shaking table tests of EPS block lightweight embankment resting on liquefiable ground[C]//Proceeding of the International Workshop on Lightweight GeoMaterials.Tokyo:Japanese Geitechnical Society,2002:77-82.
[10]王庶懋,高玉峰,张益纯.动荷载下砂土与EPS颗粒混合的轻质土(LSES)的强度标准及破坏机理研究[J].河海大学学报(自然科学报),2007,35(2):197-200.Wang S M,Gao Y F,Zhang Y C.Study on strength criteria and failure mechanism of lightweight sand-EPS beads soil(LSES)under dynamic loads[J].Journal of Hohai University(Natural Science Edition),2007,35(2):197-200.
[11]黎冰,高玉峰,丰土根.振动频率对LCES动力特性的影响分析及其机理初探[J].岩土力学,2008,29(10):2731-2740.Li B,Gao Y F,Feng T G.Cyclic loading frequency effect and mechanism of lightweight clay-EPS beads soil[J].Rock and Soil Mechanics,2008,29(10):2731-2740.
[12]侯天顺.淤泥发泡颗粒混合轻量土力学性质的试验研究[D].武汉:中国地质大学,2008.Hou T S.Experimental study on mechanical properties of foamed particle light weight soil mixed with silt[D].Wuhan:China University of Geoceiences,2008.
[13]侯天顺,徐光黎.发泡颗粒混合轻量土三轴应力-应变-孔压特性试验[J].中国公路学报,2009,22(6):10-17.Hou T S,Xu G L.Experiment on triaxial pore water pressstress-strain characteristics of foamed particle light weight soil[J].China Journal of Highway and Transport,2009,22(6):10-17.
[14]谢定义.土动力学[M].北京:高等教育出版社,2011:141-179.Xie D Y.Soil Dynamics[M].Beijing:Higher Education Press,2011:141-179.
[15]Seed H B.Soil liquefaction and cyclic mobility evaluation for level ground during earthquake[J].Journal of the Geotechnical&Geoenvironmental Engineering,1979,105(2):201-255.
[16]廖红建,吴建英,黄飞强,等.用统一强度理论求解岩土材料的动力强度参数[J].岩石力学与工程学报,2003,22(12):1994-2000.Liao H J,Wu J Y,Huang F Q,et al.Determination of dynamic strength parameters of geomaterials based on unified strength theory[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(12):1994-2000.
[17]温晓贵,张勋,周建,等.复杂应力路径下杭州原状软黏土破坏标准研究[J].岩土力学,2010,31(9):2793-2798.Wen X G,Zhang X,Zhou J,et al.Study of failure criterion for Hangzhou intact soft clay under complex stress path[J].Rock and Soil Mechanics,2010,31(9):2793-2798.
[18]陈国兴,孙田,王炳辉,等.循环荷载作用下饱和砂砾土的破坏机理与动强度[J].岩土工程学报,2015,37(12):2140-2148.Chen G X,Sun T,Wang B H,et al.Undrained cyclic failure mechanisms and resistance of saturated sand-gravel mixture[J].Chinese Journal of Geotechnical Engineering,2015,37(12):2140-2148.
[19]童瑞铭.EPS颗粒混合轻质土(LSES)与砂土的动力特性对比试验研究[D].南京:河海大学,2007.Tong R M.Comparative experiment research on dynamic behaviors of lightweight sand-EPS beads soil with sand[D].Nanjing:Hohai University,2007.
[20]杨利国,骆亚生,李炎,等.初始应力条件对压实黄土动强度影响的研究[J].岩土力学,2010,31(1):87-91.Yang L G,Luo Y S,Li Y,et al.Research on effect of initial stress conditions on dynamic strength of compacted loess[J].Rock and Soil Mechanics,2010,31(1):87-91.
[21]高玉峰,黎冰.黏土与EPS颗粒混合轻质土的动强度特性试验研究[J].岩石力学与工程学报,2007,26(2):4276-4283.Gao Y F,Li B.Experimental study on dynamic strength properties of lightweight clay mixed with EPS beads soil[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(2):4276-4283.
[22]辛凌,刘汉龙,沈杨,等.废弃轮胎橡胶颗粒轻质混合土强度特性试验研究[J].岩石力学与工程学报,2010,32(3):428-433.Xin L,Liu H L,Shen Y,et al.Consolidated undrained triaxial compression tests on lightweight soil mixed with rubber chips of scrap tires[J].Chinese Journal of Rock Mechanics and Engineering,2010,32(3):428-433.
[23]姬凤玲,李强.疏浚淤泥EPS颗粒轻质土等向压缩变形特性研究[J].环境科学与技术,2016,39(S1):16-19.Ji F L,Li Q.Study on the isotropic compression deformation properties of lightweight EPS-bead-treated soil made from dredging silt[J].Environmental Science&Technology,2016,39(S1):16-19.
[24]董金梅,刘汉龙,洪振舜,等.聚苯乙烯轻质混合土三轴压缩试验研究[J].河海大学学报(自然科学版),2005,33(1):99-103.Dong J M,Liu H L,Hong Z S,et al.Study on properties of lightweight polystyrene heterogeneous soil with triaxial compression tests[J].Journal of Hohai University(Natural Sciences Edition),2005,33(1):99-103.
[25]黎冰.动荷载下粘土与EPS颗粒混合轻质土的变形和强度特性试验研究[D].南京:河海大学,2007.Li B.Experimental study on the deformation and strength properties of lightweight clay-EPS beads soil under cyclic loading[D].Nanjing:Hohai University,2007.
[2]李明东,朱伟,马殿光,等.EPS颗粒混合轻质土的施工技术以及应用实例[J].岩土工程学报,2006,28(4):533-536.Li M D,Zhu W,Ma D G,et al.Construction technology and application in-situ of expanded polystyrene treated lightweight soil[J].Chinese Journal of Geotechnical Engineering,2006,28(4):533-536.
[3]蔡骁,高洪梅,赵晖,等.轨道交通荷载作用下EPS颗粒轻质混合土的动力特性研究[J].防灾减灾工程学报,2015,35(5):651-658.Cai X,Gao H M,Zhao H,et al.Dynamic characteristics of EPScomposite lightweight soil under railway loading[J].Journal of Disaster Prevention and Mitigation Engineering,2015,35(5):651-658.
[4]Hou T S.Influence of expanded polystyrene size on deformation characteristics of light weight soil[J].Journal of Central South University,2012,19:3320-3328.
[5]侯天顺,徐光黎.发泡颗粒混合轻量土抗剪强度特性试验研究[J].中国矿业大学学报,2010,39(4):534-540.Hou T S,Xu G L.Experimental study on the shear strength characteristics of foamed particle light weight soil[J].Journal of China University of Mining&Technology,2010,39(4):534-540.
[6]侯天顺.轻量土击实模型与工程特性[J].岩土工程学报,2014,36(11):2127-2135.Hou T S.Model for compaction density and engineering properties of light weight soil[J].Chinese Journal of Geotechnical Engineerding,2014,36(11):2127-2135.
[7]朱伟,姬凤玲,李明东,等.轻质土密度、强度与材料组成的关系研究[J].岩土力学,2007,28(7):1411-1414.Zhu W,Ji F L,Li M D,et al.Relationships among density,strength and materials of lightweight treated soil[J].Rock and Soil Mechanics,2007,28(7):1411-1414.
[8]Yasuhara K.Recent Japanese experiences with lightweight geomaterials[C]//Proceeding of the International Workshop on Lightweight Geo-Materials.Tokyo:Japanese Geitechnical Society,2002:35-60.
[9]Kojima K,Maruoka M.Shaking table tests of EPS block lightweight embankment resting on liquefiable ground[C]//Proceeding of the International Workshop on Lightweight GeoMaterials.Tokyo:Japanese Geitechnical Society,2002:77-82.
[10]王庶懋,高玉峰,张益纯.动荷载下砂土与EPS颗粒混合的轻质土(LSES)的强度标准及破坏机理研究[J].河海大学学报(自然科学报),2007,35(2):197-200.Wang S M,Gao Y F,Zhang Y C.Study on strength criteria and failure mechanism of lightweight sand-EPS beads soil(LSES)under dynamic loads[J].Journal of Hohai University(Natural Science Edition),2007,35(2):197-200.
[11]黎冰,高玉峰,丰土根.振动频率对LCES动力特性的影响分析及其机理初探[J].岩土力学,2008,29(10):2731-2740.Li B,Gao Y F,Feng T G.Cyclic loading frequency effect and mechanism of lightweight clay-EPS beads soil[J].Rock and Soil Mechanics,2008,29(10):2731-2740.
[12]侯天顺.淤泥发泡颗粒混合轻量土力学性质的试验研究[D].武汉:中国地质大学,2008.Hou T S.Experimental study on mechanical properties of foamed particle light weight soil mixed with silt[D].Wuhan:China University of Geoceiences,2008.
[13]侯天顺,徐光黎.发泡颗粒混合轻量土三轴应力-应变-孔压特性试验[J].中国公路学报,2009,22(6):10-17.Hou T S,Xu G L.Experiment on triaxial pore water pressstress-strain characteristics of foamed particle light weight soil[J].China Journal of Highway and Transport,2009,22(6):10-17.
[14]谢定义.土动力学[M].北京:高等教育出版社,2011:141-179.Xie D Y.Soil Dynamics[M].Beijing:Higher Education Press,2011:141-179.
[15]Seed H B.Soil liquefaction and cyclic mobility evaluation for level ground during earthquake[J].Journal of the Geotechnical&Geoenvironmental Engineering,1979,105(2):201-255.
[16]廖红建,吴建英,黄飞强,等.用统一强度理论求解岩土材料的动力强度参数[J].岩石力学与工程学报,2003,22(12):1994-2000.Liao H J,Wu J Y,Huang F Q,et al.Determination of dynamic strength parameters of geomaterials based on unified strength theory[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(12):1994-2000.
[17]温晓贵,张勋,周建,等.复杂应力路径下杭州原状软黏土破坏标准研究[J].岩土力学,2010,31(9):2793-2798.Wen X G,Zhang X,Zhou J,et al.Study of failure criterion for Hangzhou intact soft clay under complex stress path[J].Rock and Soil Mechanics,2010,31(9):2793-2798.
[18]陈国兴,孙田,王炳辉,等.循环荷载作用下饱和砂砾土的破坏机理与动强度[J].岩土工程学报,2015,37(12):2140-2148.Chen G X,Sun T,Wang B H,et al.Undrained cyclic failure mechanisms and resistance of saturated sand-gravel mixture[J].Chinese Journal of Geotechnical Engineering,2015,37(12):2140-2148.
[19]童瑞铭.EPS颗粒混合轻质土(LSES)与砂土的动力特性对比试验研究[D].南京:河海大学,2007.Tong R M.Comparative experiment research on dynamic behaviors of lightweight sand-EPS beads soil with sand[D].Nanjing:Hohai University,2007.
[20]杨利国,骆亚生,李炎,等.初始应力条件对压实黄土动强度影响的研究[J].岩土力学,2010,31(1):87-91.Yang L G,Luo Y S,Li Y,et al.Research on effect of initial stress conditions on dynamic strength of compacted loess[J].Rock and Soil Mechanics,2010,31(1):87-91.
[21]高玉峰,黎冰.黏土与EPS颗粒混合轻质土的动强度特性试验研究[J].岩石力学与工程学报,2007,26(2):4276-4283.Gao Y F,Li B.Experimental study on dynamic strength properties of lightweight clay mixed with EPS beads soil[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(2):4276-4283.
[22]辛凌,刘汉龙,沈杨,等.废弃轮胎橡胶颗粒轻质混合土强度特性试验研究[J].岩石力学与工程学报,2010,32(3):428-433.Xin L,Liu H L,Shen Y,et al.Consolidated undrained triaxial compression tests on lightweight soil mixed with rubber chips of scrap tires[J].Chinese Journal of Rock Mechanics and Engineering,2010,32(3):428-433.
[23]姬凤玲,李强.疏浚淤泥EPS颗粒轻质土等向压缩变形特性研究[J].环境科学与技术,2016,39(S1):16-19.Ji F L,Li Q.Study on the isotropic compression deformation properties of lightweight EPS-bead-treated soil made from dredging silt[J].Environmental Science&Technology,2016,39(S1):16-19.
[24]董金梅,刘汉龙,洪振舜,等.聚苯乙烯轻质混合土三轴压缩试验研究[J].河海大学学报(自然科学版),2005,33(1):99-103.Dong J M,Liu H L,Hong Z S,et al.Study on properties of lightweight polystyrene heterogeneous soil with triaxial compression tests[J].Journal of Hohai University(Natural Sciences Edition),2005,33(1):99-103.
[25]黎冰.动荷载下粘土与EPS颗粒混合轻质土的变形和强度特性试验研究[D].南京:河海大学,2007.Li B.Experimental study on the deformation and strength properties of lightweight clay-EPS beads soil under cyclic loading[D].Nanjing:Hohai University,2007.