制样方法对粉土力学特性及孔隙特征的影响
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摘要
以郑州粉土为研究对象,分别采用静力压实法和动力击实法制取试样,并进行三轴剪切试验与压汞试验测定其力学特性和孔隙分布曲线,研究制样条件对粉土力学特性及孔隙结构分布的影响。结果表明:制样方法及制样含水率对土样应力–应变曲线形态的影响和围压有关。动力击实样应力–应变关系由低围压和低含水率下的应变软化型向较大围压和较大含水率下的应变硬化型过渡,而静力压实样则始终呈应变硬化特性。2种制样方法所得试样的剪切强度和黏聚力均在最优含水率时最大,但对于相同的制样含水率,击实样剪切强度和黏聚力均高于压实样,而制样方法对粉土残余黏聚力的影响可忽略。另外,制样条件对土样的内摩擦角和残余内摩擦角影响均很小。压汞试验表明,与击实样相比,压实样的孔径分布曲线整体呈向右平移趋势,峰值孔径及分布密度增大,且团粒内较大孔隙含量较多。这一定程度上可以解释静力压实样和动力击实样力学性状的演化规律。
Taking Zhengzhou silt as the research object,the samples were prepared by static and dynamic compaction methods,and a series of triaxial shear tests and mercury injection tests were carried out to study the influence of different sample preparation conditions on mechanical behaviours and pore structure distribution of silt. The results show that the influence of the sample preparation method and the water content on the stress and strain relationship depends on the confining pressure. The stress and strain relationship of dynamic compaction samples transfers from the strain softening type with lower confining pressure and lower water content to the strain hardening type with larger confining pressure and larger water content,while the relationship of static compaction samples is always the strain hardening type. The shear strength and the cohesion of the samples obtained by the two sample preparation methods reach the maximums at the optimal moisture content. The shear strength and the cohesion of the dynamic compacted samples are higher than those of the static compacted samples for the case of the same water content,while the sample preparation method has no obvious influence on the residual cohesion of silty soil. Mercury injection test results indicate that,compared with the dynamic compaction samples,the pore diameter distribution curve of the static compaction samples shifts to the right as a whole,the peak pore diameter and distribution density increase and the larger pore content is more. The research results can explain the evolution law of the mechanical property of the static and dynamic compaction samples to some extent.
Taking Zhengzhou silt as the research object,the samples were prepared by static and dynamic compaction methods,and a series of triaxial shear tests and mercury injection tests were carried out to study the influence of different sample preparation conditions on mechanical behaviours and pore structure distribution of silt. The results show that the influence of the sample preparation method and the water content on the stress and strain relationship depends on the confining pressure. The stress and strain relationship of dynamic compaction samples transfers from the strain softening type with lower confining pressure and lower water content to the strain hardening type with larger confining pressure and larger water content,while the relationship of static compaction samples is always the strain hardening type. The shear strength and the cohesion of the samples obtained by the two sample preparation methods reach the maximums at the optimal moisture content. The shear strength and the cohesion of the dynamic compacted samples are higher than those of the static compacted samples for the case of the same water content,while the sample preparation method has no obvious influence on the residual cohesion of silty soil. Mercury injection test results indicate that,compared with the dynamic compaction samples,the pore diameter distribution curve of the static compaction samples shifts to the right as a whole,the peak pore diameter and distribution density increase and the larger pore content is more. The research results can explain the evolution law of the mechanical property of the static and dynamic compaction samples to some extent.
引文
[1]SEED H B.Structure and strength characteristics of compacted clay[J].Proceeding of American Society of Civil Engineers,1960,85:87-128.
[2]PAPADIMITRIOU A G,DAFALIAS Y F,YOSHIMINE M.Plasticity modeling of the effect of sample preparation method on sand response[J].Soil and Foundations,2005,45(2):109-124.
[3]李广信.高等土力学[M].2版.北京:清华大学出版社,2016:137-176.(LI Guangxin.Advanced soil mechanics[M].2nd ed.Beijing:Tsinghua University Press,2016:137-176.(in Chinese))
[4]SIVAKUMAR V,WHEELER S J.Influence of compaction procedure on the mechanical behavior of an unsaturated compacted clay Part 1:Wetting and isotropic compression[J].Geotechnique,2000,50(4):359-368.
[5]AHMED S,LOVELL C W,DIAMOND S.Pore sizes and strength of compacted clay[J].Journal of the Geotechnical Engineering Division.,ASCE,1974,100:407-425.
[6]EKWUE E I,BIRCH R,CHEWITT J.Effect of dynamic and static methods of compaction on soil strength[J].West Indian Journal of Engineering,2015,37(2):74-78.
[7]KENAI S,BAHAR R,BENAZZOUG M.Experimental analysis of the effect of some compaction methods on mechanical properties and durability of cement stabilized soil[J].Journal of Materials Science,2006,41(21):6 956-6 964.
[8]SEED H B.Stability and swell pressure characteristics of compacted clays[J].Clays and Clay Minerals,1954,3(1):483-504.
[9]CRISPIM F A,LIMA D C D,SCHAEFER C E G R,et al.The influence of laboratory compaction methods on soil structure:Mechanical and micromorphological analyses[J].Soils and Rocks,2011,34(1):91-98.
[10]刘延志,胡敏云,沈映,等.杭州市粉土的各向异性室内试验研究[J].浙江工业大学学报,2012,40(2):188-192.(LIU Yanzhi,HU Minyun,SHEN Ying,et al.Experiment on the anisotropy of Hangzhou silt[J].Journal of Zhejiang University of Technology,2012,40(2):188-192.(in Chinese))
[11]李春清,梁庆国,吴旭阳,等.重塑黄土抗拉强度试验研究[J].地震工程学报,2014,36(2):233-238.(LI Chunqing,LIANG Qingguo,WU Xuyang,et al.Study on the test of tensile strength of remolded loess[J].China Earthquake Engineering Journal,2014,36(2):233-238.(in Chinese))
[12]左巍然,杨和平,刘平.确定膨胀土残余强度的试验研究[J].长沙交通学院学报,2007,23(1):23-27.(ZUO Weiran,YANG Heping,LIU Ping.Study on the determination of residual strength for expansive soil[J].Journal of Changsha Communications University,2007,23(1):23-27.(in Chinese))
[13]DELAGE P,AUDIGUIER M,CUI Y J,et al.Microstructure of a compacted silt[J].Canadian Geotechnical Journal,1996,33(1):150-158.
[14]OUALMAKRAN M,MERCATORIS B C N,FRAN?OIS B.Pore size distribution of a compacted silty soil after compaction,saturation and loading[J].Canadian Geotechnical Journal,2016,53(12):1 902-1 909.
[15]MAGISTRIS F,TATSUOKA F.Effects of moulding water content of the stress-strain behaviour of a compacted silty sand[J].Soils and Foundations,2004,44(2):85-101.
[16]郭莹,王跃新.原状与重塑粉土固结不排水剪切特性的对比试验[J].水利学报,2011,39(1):68-75.(GUO Ying,WANG Yuexin.Comparative test study on consolidation un-drained shear characteristics of undisturbed and remolded silt[J].Journal of Hydraulic Engineering,2011,39(1):68-75.(in Chinese))
[17]LAMBE T W.The engineering behaviour of compacted clay[J].Journal of Soil Mechanics and Foundations Division,ASCE,1958,84(2):1 651-1 655.
[18]申爱琴,李祥文.含砂低液限粉土填筑路基压实机理及施工技术研究[J].中国公路学报,2000,13(4):12-15.(SHEN Aiqin,LIXiangwen.Study of compacting mechanism and construction technology of filling road bed with bearing sand silt of low liquid limit[J].China Journal of Highway and Transport,2000,13(4):12-15.(in Chinese))
[19]谈云志,郑爱,吴翩,等.初始状态对粉土强度的影响试验研究[J].公路,2012,(10):148-150.(TAN Yunzhi,ZHENG Ai,WU Bian,et al.Experimental study on the effect of initial state on strength of silt[J].Highway,2012,(10):148-150.(in Chinese))
[20]孙德安,高游.不同制样方法非饱和土的持水特性研究[J].岩土工程学报,2015,37(1):91-97.(SUN Dean,GAO You.Water retention behaviour of soils with different preparations[J].Chinese Journal of Geotechnical Engineering,2015,37(1):91-97.(in Chinese))
[21]PENUMADU D,JOHN D.Compressibility effect in evaluating the pore-size distribution of kaolin clay using mercury intrusion porosimetry[J].Canadian Geotechnical Journal,2000,37(2):397-400.
[22]LADD R S.Preparing testing specimen using under compaction[J].ASTM,Geotechnial Testing Journal,1978,1(1):16-23.
[23]王洪瑾,周国平,周克骥.固有和诱发各向异性对击实粘性土强度和变形特性的影响[J].岩土工程学报,1996,18(3):1-10.(WANGHongjin,ZHOU Guoping,ZHOU Keji.Effect of inherent and induced anisotropy on shear strength and deformation characteristics of compacted cohesive soil[J].Chinese Journal of Geotechnical Engineering,1996,18(3):1-10.(in Chinese))
[24]KODIKARA J,BARBOUR S L,FREDLUND D G.Changein clay structure behaviour due to wetting and drying[C]//Proceedings of the8th Australian-Zealand Conference on Geomechanics.Hobart:[s.n.],1999:179-185.
[25]SHEAR D L,OLSEN H W,NELSON K R.Effects of desiccation on the hydraulic conductivity versus void ratio relationship for a natural clay[R].Washington D C:National Academy Press,1993:1 365-1 370.
[26]贾敏才,王磊,周健.砂性土宏细观强夯加固机制的试验研究[J].岩石力学与工程学报,2009,28(增1):3 282-3 290.(JIAMincai,WANG Lei,ZHOU Jian.Experimental research on macro-meso consolidation mechanism of sandy soil with dynamic compaction[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.1):3 282-3 290.(in Chinese))
[27]施斌.粘性土击实过程中微观结构的定量评价[J].岩土工程学报,1996,18(4):57-62.(SHI Bin.Quantitative assessment of changes of microstructure for clayed soil in the process of compaction[J].Chinese Journal of Geotechnical Engineering,1996,18(4):57-62.(in Chinese))
[28]高国瑞.近代土质学[M].2版.北京:科学出版社,2013:133-139.(GAO Guorui.Neoteric soil geotechnology[M].2nd ed.Beijing:Science Press,2013:133-139.(in Chinese))
[2]PAPADIMITRIOU A G,DAFALIAS Y F,YOSHIMINE M.Plasticity modeling of the effect of sample preparation method on sand response[J].Soil and Foundations,2005,45(2):109-124.
[3]李广信.高等土力学[M].2版.北京:清华大学出版社,2016:137-176.(LI Guangxin.Advanced soil mechanics[M].2nd ed.Beijing:Tsinghua University Press,2016:137-176.(in Chinese))
[4]SIVAKUMAR V,WHEELER S J.Influence of compaction procedure on the mechanical behavior of an unsaturated compacted clay Part 1:Wetting and isotropic compression[J].Geotechnique,2000,50(4):359-368.
[5]AHMED S,LOVELL C W,DIAMOND S.Pore sizes and strength of compacted clay[J].Journal of the Geotechnical Engineering Division.,ASCE,1974,100:407-425.
[6]EKWUE E I,BIRCH R,CHEWITT J.Effect of dynamic and static methods of compaction on soil strength[J].West Indian Journal of Engineering,2015,37(2):74-78.
[7]KENAI S,BAHAR R,BENAZZOUG M.Experimental analysis of the effect of some compaction methods on mechanical properties and durability of cement stabilized soil[J].Journal of Materials Science,2006,41(21):6 956-6 964.
[8]SEED H B.Stability and swell pressure characteristics of compacted clays[J].Clays and Clay Minerals,1954,3(1):483-504.
[9]CRISPIM F A,LIMA D C D,SCHAEFER C E G R,et al.The influence of laboratory compaction methods on soil structure:Mechanical and micromorphological analyses[J].Soils and Rocks,2011,34(1):91-98.
[10]刘延志,胡敏云,沈映,等.杭州市粉土的各向异性室内试验研究[J].浙江工业大学学报,2012,40(2):188-192.(LIU Yanzhi,HU Minyun,SHEN Ying,et al.Experiment on the anisotropy of Hangzhou silt[J].Journal of Zhejiang University of Technology,2012,40(2):188-192.(in Chinese))
[11]李春清,梁庆国,吴旭阳,等.重塑黄土抗拉强度试验研究[J].地震工程学报,2014,36(2):233-238.(LI Chunqing,LIANG Qingguo,WU Xuyang,et al.Study on the test of tensile strength of remolded loess[J].China Earthquake Engineering Journal,2014,36(2):233-238.(in Chinese))
[12]左巍然,杨和平,刘平.确定膨胀土残余强度的试验研究[J].长沙交通学院学报,2007,23(1):23-27.(ZUO Weiran,YANG Heping,LIU Ping.Study on the determination of residual strength for expansive soil[J].Journal of Changsha Communications University,2007,23(1):23-27.(in Chinese))
[13]DELAGE P,AUDIGUIER M,CUI Y J,et al.Microstructure of a compacted silt[J].Canadian Geotechnical Journal,1996,33(1):150-158.
[14]OUALMAKRAN M,MERCATORIS B C N,FRAN?OIS B.Pore size distribution of a compacted silty soil after compaction,saturation and loading[J].Canadian Geotechnical Journal,2016,53(12):1 902-1 909.
[15]MAGISTRIS F,TATSUOKA F.Effects of moulding water content of the stress-strain behaviour of a compacted silty sand[J].Soils and Foundations,2004,44(2):85-101.
[16]郭莹,王跃新.原状与重塑粉土固结不排水剪切特性的对比试验[J].水利学报,2011,39(1):68-75.(GUO Ying,WANG Yuexin.Comparative test study on consolidation un-drained shear characteristics of undisturbed and remolded silt[J].Journal of Hydraulic Engineering,2011,39(1):68-75.(in Chinese))
[17]LAMBE T W.The engineering behaviour of compacted clay[J].Journal of Soil Mechanics and Foundations Division,ASCE,1958,84(2):1 651-1 655.
[18]申爱琴,李祥文.含砂低液限粉土填筑路基压实机理及施工技术研究[J].中国公路学报,2000,13(4):12-15.(SHEN Aiqin,LIXiangwen.Study of compacting mechanism and construction technology of filling road bed with bearing sand silt of low liquid limit[J].China Journal of Highway and Transport,2000,13(4):12-15.(in Chinese))
[19]谈云志,郑爱,吴翩,等.初始状态对粉土强度的影响试验研究[J].公路,2012,(10):148-150.(TAN Yunzhi,ZHENG Ai,WU Bian,et al.Experimental study on the effect of initial state on strength of silt[J].Highway,2012,(10):148-150.(in Chinese))
[20]孙德安,高游.不同制样方法非饱和土的持水特性研究[J].岩土工程学报,2015,37(1):91-97.(SUN Dean,GAO You.Water retention behaviour of soils with different preparations[J].Chinese Journal of Geotechnical Engineering,2015,37(1):91-97.(in Chinese))
[21]PENUMADU D,JOHN D.Compressibility effect in evaluating the pore-size distribution of kaolin clay using mercury intrusion porosimetry[J].Canadian Geotechnical Journal,2000,37(2):397-400.
[22]LADD R S.Preparing testing specimen using under compaction[J].ASTM,Geotechnial Testing Journal,1978,1(1):16-23.
[23]王洪瑾,周国平,周克骥.固有和诱发各向异性对击实粘性土强度和变形特性的影响[J].岩土工程学报,1996,18(3):1-10.(WANGHongjin,ZHOU Guoping,ZHOU Keji.Effect of inherent and induced anisotropy on shear strength and deformation characteristics of compacted cohesive soil[J].Chinese Journal of Geotechnical Engineering,1996,18(3):1-10.(in Chinese))
[24]KODIKARA J,BARBOUR S L,FREDLUND D G.Changein clay structure behaviour due to wetting and drying[C]//Proceedings of the8th Australian-Zealand Conference on Geomechanics.Hobart:[s.n.],1999:179-185.
[25]SHEAR D L,OLSEN H W,NELSON K R.Effects of desiccation on the hydraulic conductivity versus void ratio relationship for a natural clay[R].Washington D C:National Academy Press,1993:1 365-1 370.
[26]贾敏才,王磊,周健.砂性土宏细观强夯加固机制的试验研究[J].岩石力学与工程学报,2009,28(增1):3 282-3 290.(JIAMincai,WANG Lei,ZHOU Jian.Experimental research on macro-meso consolidation mechanism of sandy soil with dynamic compaction[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.1):3 282-3 290.(in Chinese))
[27]施斌.粘性土击实过程中微观结构的定量评价[J].岩土工程学报,1996,18(4):57-62.(SHI Bin.Quantitative assessment of changes of microstructure for clayed soil in the process of compaction[J].Chinese Journal of Geotechnical Engineering,1996,18(4):57-62.(in Chinese))
[28]高国瑞.近代土质学[M].2版.北京:科学出版社,2013:133-139.(GAO Guorui.Neoteric soil geotechnology[M].2nd ed.Beijing:Science Press,2013:133-139.(in Chinese))
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