考虑微结构特征的黄土动力特性影响因素研究
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摘要
选取1920年海原地震震中滑坡密集分布区宁夏回族自治区西吉县庞湾乡的黄土,分别进行了不同围压,不同含水率条件下的原状、重塑土动三轴试验。结合动三轴试验前后的微观变化图像,探讨围压和水分对黄土试样土颗粒的作用机制,从微结构的角度阐释了两者对黄土动力特性影响的特点。研究结果表明:所取试样动剪切模量与动剪应变的关系可以用HD模型的推导式拟合,随含水率增加,围压减小,参数a,b值增大;水分在原状试样和重塑试样的作用不同,随着含水率的增加,动剪切模量降低,阻尼比增大,原状试样动剪切模量和阻尼比的变化速率先快后慢,而重塑试样相应值的变化速率先慢后快;除了水分和围压等外在条件的影响,土样本身土体的微观特征如孔隙分布、颗粒大小、粒间间距、联结方式、密实程度等因素对土体动剪切模量和阻尼比等宏观特性产生重要影响。
Xijipangwan of Ningxia province is the intensive landslide area caused by the famous Haiyuan earthquake. Its loess is chosen as the research object. The dynamic triaxial tests are carried out on the undisturbed loess and the remolded loess under different water contents and different stress states. This paper examines the changes of microscopic images before and after dynamic triaxial tests. It discusses the action mechanism of confiningpressure and moisture on loess soil particles and explains their influence characteristics on dynamic behaviors of loess from the perspective of the microstructure. The results indicate as follows. The relationship curve of dynamic shear modulus and dynamic shear strain can be regressed by derivation of the H-D model. With the increase of water content or the decrease of confining pressure,the value of parameter a and b increase. It is founded that there are some differences between the influence of water to undisturbed samples and remolded samples. With the increase of water content,dynamic shear modulus decreases,damping ratio increases. The dynamic characteristic parameters of remolded samples are transformed quickly before they are slow. Those parameters of undisturbed samples change slowly before they are quick. Besides the influence of external conditions( such as moisture and confining pressure),the microscopic characteristics of soil samples( such as pore size distribution,particle size,inter-particle spacing,connection mode and density) have great influence on the macroscopic behaviors( such as dynamic shear modulus and damping ratio) of loess.
Xijipangwan of Ningxia province is the intensive landslide area caused by the famous Haiyuan earthquake. Its loess is chosen as the research object. The dynamic triaxial tests are carried out on the undisturbed loess and the remolded loess under different water contents and different stress states. This paper examines the changes of microscopic images before and after dynamic triaxial tests. It discusses the action mechanism of confiningpressure and moisture on loess soil particles and explains their influence characteristics on dynamic behaviors of loess from the perspective of the microstructure. The results indicate as follows. The relationship curve of dynamic shear modulus and dynamic shear strain can be regressed by derivation of the H-D model. With the increase of water content or the decrease of confining pressure,the value of parameter a and b increase. It is founded that there are some differences between the influence of water to undisturbed samples and remolded samples. With the increase of water content,dynamic shear modulus decreases,damping ratio increases. The dynamic characteristic parameters of remolded samples are transformed quickly before they are slow. Those parameters of undisturbed samples change slowly before they are quick. Besides the influence of external conditions( such as moisture and confining pressure),the microscopic characteristics of soil samples( such as pore size distribution,particle size,inter-particle spacing,connection mode and density) have great influence on the macroscopic behaviors( such as dynamic shear modulus and damping ratio) of loess.
引文
Chen G X,Liu X Z,Zhu D H,et al.2006.Experimental studies on dynamic shear modulus ratio and damping ratio of recently deposited soils in Nanjing[J].Chinese Journal of Geotechnical Engineering,28(8):1023-1027.
Gao G R.1984.Microstructure of loess soil in China relative to geographic and Geologic environment[J].Acta eological Sinica,58(3):265-272.
Hardin B O,Drnevich V P.1972.Shear modulus and damping in soils:design equation and curves[J].Journal of Soil Mechanics and Foundation Division,ASCE,98(7):667-692.
He W M,Li D Q,Yang J,et al.2016.Recent progress in research on dynamic shear modulus,damping ratio,and poisson ratio of soils[J].China Earthquake Engineering Journal,38(2):309-317.
Hu Y X.2006.Earthquake Engineering[M].Beijing:Seismological Press.
Huang R Q.2008.Catastrophic landslides in China[M].Beijing:Science Press.
Huang Z Q,Wu C,Bi L Y,et al.2017.Experimental study on influencing factors of dynamic shear module and damping ratio of fault gouce[J].Journal of Engineering Geology,25(1):50-57.
Li Q Y,Cheng X Y,Cai D Y.1985.Dynamic properties of loess under earthquake loading[J].Journal of Xi'an University of Architecture&Technology(Natural Science Edition),(3):9-37.
Li Z,Li H E,He Y J.2014.Experimental study on dynamic shear module and damping ratio of Shanxi area loess[J].Journal of Disaster Prevention and Mitigation Engineering,34(4):523-528.
Lu Y X.2007.Landform characteristics of seismic landslides in Xiji county,Ningxia province,and discussion on the countermeasures of landslide exploration and disaster mitigation[J].Northwestern Seismological Journal,29(1):79-83.
Peng J B,Lin H Z,Wang Q Y,et al.2014.The critical issues and creative concepts in mitigation research of loess geological hazards[J].Journal of Engineering Geology,22(4):684-691.
Qi J F,Luan M T,Yang Q,et al.2008.Dynamic shear modulus and damping ratio of saturated clay[J].Chinese Journal of Geotechnical Engineering,30(4):518-523.
Tian G L,Chen H E,Leng G J,et al.2016.Influence of drainage on dynamic characteristic and Microstructure of loess[J].Journal of Engineering Geology,24(S1):1024-1033.
Wang N Q,Luo D H,Yao Y,et al.2011.Dynamic strength and Microstructure change of Malan loess under triaxal cyclic loading[J].Journal of Engineering Geology,19(4):467-471.
Xu S M,Wu Z J,Zhao W C,et al.2017.Study of microscopic pore of structured loess based on matlab and IPP[J].China Earthquake Engineering Journal,39(1):80-87,94.
Yuan X M,Sun R,Sun J,et al.2000.Laboratory experimental study on dynamic shear modulus ratio and damping ratio of soils[J].Earthquake Engineering and Engineering Vibration,20(4):133-139.
Zhang Z Z.1999.Prediction of seismic hazard of loess[M].Beijing:Seismological Press.
陈国兴,刘雪珠,朱定华,等.2006.南京新近沉积土动剪切模量比与阻尼比的试验研究[J].岩土工程学报,28(8):1023-1027.
高国瑞.1984.中国黄土的微结构与地理、地质环境的关系[J].地质学报,58(3):265-272.
贺为民,李德庆,杨杰,等.2016.土的动剪切模量、阻尼比和泊松比研究进展[J].地震工程学报,38(2):309-317.
胡聿贤.2006.地震工程学[M].北京:地震出版社.
李启鹞,程显尧,蔡东艳.1985.地震荷载下黄土的动力特性[J].西安冶金建筑学院学报(自然科学版),(3):9-37.
黄润秋.2008.中国典型灾难性滑坡[M].北京:科学出版社.
黄志全,吴超,毕理毅,等.2017.断层泥动剪切模量和阻尼比影响因素试验研究[J].工程地质学报,25(1):50-57.
李铮,李宏恩,何勇军.2014.山西黄土动剪切模量与阻尼比试验研究[J].防灾减灾工程学报,34(4):523-528.
卢育霞.2007.宁夏西吉县境地震滑坡的地貌特征及其减灾开发对策探讨[J].西北地震学报,29(1):79-83.
彭建兵,林鸿州,王启耀,等.2014.黄土地质灾害研究中的关键问题与创新思路[J].工程地质学报,22(4):684-691.
齐剑峰,栾茂田,杨庆,等.2008.饱和黏土动剪切模量与阻尼比的试验研究[J].岩土工程学报,30(4):518-523.
田桂莉,陈慧娥,冷冠军,等.2016.排水对黄土动力特性及微观结构特征的影响研究[J].工程地质学报,24(S1):1024-1033.
王念秦,罗东海,姚勇,等.2011.马兰黄土动强度及其微结构变化实验[J].工程地质学报,19(4):467-471.
徐世民,吴志坚,赵文琛,等.2017.基于Matlab和IPP的黄土孔隙微观结构研究[J].地震工程学报,39(1):80-87,94.
袁晓铭,孙锐,孙静,等.2000.常规土类动剪切模量比和阻尼比试验研究[J].地震工程与工程振动,20(4):133-139.
张振中.1999.黄土地震灾害预测[M].北京:地震出版社.
Gao G R.1984.Microstructure of loess soil in China relative to geographic and Geologic environment[J].Acta eological Sinica,58(3):265-272.
Hardin B O,Drnevich V P.1972.Shear modulus and damping in soils:design equation and curves[J].Journal of Soil Mechanics and Foundation Division,ASCE,98(7):667-692.
He W M,Li D Q,Yang J,et al.2016.Recent progress in research on dynamic shear modulus,damping ratio,and poisson ratio of soils[J].China Earthquake Engineering Journal,38(2):309-317.
Hu Y X.2006.Earthquake Engineering[M].Beijing:Seismological Press.
Huang R Q.2008.Catastrophic landslides in China[M].Beijing:Science Press.
Huang Z Q,Wu C,Bi L Y,et al.2017.Experimental study on influencing factors of dynamic shear module and damping ratio of fault gouce[J].Journal of Engineering Geology,25(1):50-57.
Li Q Y,Cheng X Y,Cai D Y.1985.Dynamic properties of loess under earthquake loading[J].Journal of Xi'an University of Architecture&Technology(Natural Science Edition),(3):9-37.
Li Z,Li H E,He Y J.2014.Experimental study on dynamic shear module and damping ratio of Shanxi area loess[J].Journal of Disaster Prevention and Mitigation Engineering,34(4):523-528.
Lu Y X.2007.Landform characteristics of seismic landslides in Xiji county,Ningxia province,and discussion on the countermeasures of landslide exploration and disaster mitigation[J].Northwestern Seismological Journal,29(1):79-83.
Peng J B,Lin H Z,Wang Q Y,et al.2014.The critical issues and creative concepts in mitigation research of loess geological hazards[J].Journal of Engineering Geology,22(4):684-691.
Qi J F,Luan M T,Yang Q,et al.2008.Dynamic shear modulus and damping ratio of saturated clay[J].Chinese Journal of Geotechnical Engineering,30(4):518-523.
Tian G L,Chen H E,Leng G J,et al.2016.Influence of drainage on dynamic characteristic and Microstructure of loess[J].Journal of Engineering Geology,24(S1):1024-1033.
Wang N Q,Luo D H,Yao Y,et al.2011.Dynamic strength and Microstructure change of Malan loess under triaxal cyclic loading[J].Journal of Engineering Geology,19(4):467-471.
Xu S M,Wu Z J,Zhao W C,et al.2017.Study of microscopic pore of structured loess based on matlab and IPP[J].China Earthquake Engineering Journal,39(1):80-87,94.
Yuan X M,Sun R,Sun J,et al.2000.Laboratory experimental study on dynamic shear modulus ratio and damping ratio of soils[J].Earthquake Engineering and Engineering Vibration,20(4):133-139.
Zhang Z Z.1999.Prediction of seismic hazard of loess[M].Beijing:Seismological Press.
陈国兴,刘雪珠,朱定华,等.2006.南京新近沉积土动剪切模量比与阻尼比的试验研究[J].岩土工程学报,28(8):1023-1027.
高国瑞.1984.中国黄土的微结构与地理、地质环境的关系[J].地质学报,58(3):265-272.
贺为民,李德庆,杨杰,等.2016.土的动剪切模量、阻尼比和泊松比研究进展[J].地震工程学报,38(2):309-317.
胡聿贤.2006.地震工程学[M].北京:地震出版社.
李启鹞,程显尧,蔡东艳.1985.地震荷载下黄土的动力特性[J].西安冶金建筑学院学报(自然科学版),(3):9-37.
黄润秋.2008.中国典型灾难性滑坡[M].北京:科学出版社.
黄志全,吴超,毕理毅,等.2017.断层泥动剪切模量和阻尼比影响因素试验研究[J].工程地质学报,25(1):50-57.
李铮,李宏恩,何勇军.2014.山西黄土动剪切模量与阻尼比试验研究[J].防灾减灾工程学报,34(4):523-528.
卢育霞.2007.宁夏西吉县境地震滑坡的地貌特征及其减灾开发对策探讨[J].西北地震学报,29(1):79-83.
彭建兵,林鸿州,王启耀,等.2014.黄土地质灾害研究中的关键问题与创新思路[J].工程地质学报,22(4):684-691.
齐剑峰,栾茂田,杨庆,等.2008.饱和黏土动剪切模量与阻尼比的试验研究[J].岩土工程学报,30(4):518-523.
田桂莉,陈慧娥,冷冠军,等.2016.排水对黄土动力特性及微观结构特征的影响研究[J].工程地质学报,24(S1):1024-1033.
王念秦,罗东海,姚勇,等.2011.马兰黄土动强度及其微结构变化实验[J].工程地质学报,19(4):467-471.
徐世民,吴志坚,赵文琛,等.2017.基于Matlab和IPP的黄土孔隙微观结构研究[J].地震工程学报,39(1):80-87,94.
袁晓铭,孙锐,孙静,等.2000.常规土类动剪切模量比和阻尼比试验研究[J].地震工程与工程振动,20(4):133-139.
张振中.1999.黄土地震灾害预测[M].北京:地震出版社.