含砾黏性土力学特性分析
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摘要
通过三轴试验,分析研究含砾黏性滑带土的力学特性,发现当砾石含量低时,主要表现出黏性土的力学特性,试样强度较低;砾石含量高时,砾石间的摩擦咬合作用增强,试样强度较高。表现出应变硬化特性,且均表现为剪缩,破坏时试样均是鼓屈变形。随着砾石含量的增加,试样的排水性能先降低后增强。砾石含量较高时,试样的排水性能明显强于砾石含量低的试样与黏性土试样。绘制了四种土样的有效应力路径,低围压时,直线不能很好地包络有效应力路径;黏粒含量低时,强度包线通过原点且是直线,较好的包络了有效应力路径。确定了修正剑桥模型中的M、λ、κ等参数并且对试验结果进行了验证,CD试验计算主应力差与试验结果吻合较好,体应变计算值与试验结果偏差较大,CU试验计算与试验结果较吻合。
The triaxial tests on the viscous slip soils containing gravels are performed to investigate their mechanical properties.It is experimentally found that when the gravels contents are low,the mechanical properties of the mixture soils are weak and their strength is low.The friction and interlock between the gravels enhances with the increasing of the contents of gravels,and the strength of the samples also enhances.Soil samples behave strain hardening,with their volumetric strains decreasing gradually and the samples presenting bulge deformation.With the increasing of the contents of gravels the drainage performance of the samples first decreases and then enhances.The drainage performance of the samples with high gravels contents is better than that of those with low gravel contents.The effective stress paths of four kinds of soils are drawn in the stress plane.Under the low confining pressure,the straight line cannot envelope the effective stress path well.When the fine contents are low,the envelope is a line through the origin which can envelope the effective stress path.The parameters of M,λandκof the modified Camclay model are determined by the soils samples of triaxial tests.A comparison of CD tests and calculations demonstrates that the principal stress difference is well,but that there are a bit of difference between the calculation results of volumetric strain with the comparisons of CU tests and calculations well.
The triaxial tests on the viscous slip soils containing gravels are performed to investigate their mechanical properties.It is experimentally found that when the gravels contents are low,the mechanical properties of the mixture soils are weak and their strength is low.The friction and interlock between the gravels enhances with the increasing of the contents of gravels,and the strength of the samples also enhances.Soil samples behave strain hardening,with their volumetric strains decreasing gradually and the samples presenting bulge deformation.With the increasing of the contents of gravels the drainage performance of the samples first decreases and then enhances.The drainage performance of the samples with high gravels contents is better than that of those with low gravel contents.The effective stress paths of four kinds of soils are drawn in the stress plane.Under the low confining pressure,the straight line cannot envelope the effective stress path well.When the fine contents are low,the envelope is a line through the origin which can envelope the effective stress path.The parameters of M,λandκof the modified Camclay model are determined by the soils samples of triaxial tests.A comparison of CD tests and calculations demonstrates that the principal stress difference is well,but that there are a bit of difference between the calculation results of volumetric strain with the comparisons of CU tests and calculations well.
引文
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[2]陈晓平,黄井武,尹赛华,等.滑带土强度特性的试验研究[J].岩土力学,2011,32(11):3212-3218.CHEN Xiaoping,HUANG Jingwu,YIN Saihua,et al.Experimental study of strength property of slip zone soils[J].Rock and Soil Mechanics,2011,32(11):3212-3218.
[3]李江,许强,胡泽铭,等.川东红层原状滑带土饱水软化试验研究[J].岩石力学与工程学报,2015,34(增刊2):4333-4342.LI Jiang,XU Qiang,HU Zeming,et al.Experimental research on softening of undisturbed saturated slip soil in eastern of Sichuan Province red bed[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(S2):4333-4342.
[4]高旭,晏鄂川,崔学杰.应变速率对含砾滑带土抗剪强度影响研究[J].水文地质工程地质,2016,43(1):94-98.GAO Xu,YAN Echuan,CUI Xuejie.Influence of strain rate to the shear strength of conglomeratic sliding-zone soil[J].Hydrogeology and Engineering Geology,2016,43(1):94-98.
[5]SKEMPTON A.W.Long-term stability of clay slopes[J].Geotechnique,1964,14(2):77-102.
[6]CHANDLER R J.Back analysis techniques for slope stabilization works:a case record[J].Geotechnique,1977,27(4):479-495.
[7]黄润秋,裴向军,崔圣华.大光包滑坡滑带岩体碎裂特征及其形成机制研究[J].岩石力学与工程学报,2016,35(1):1-15.HUANG Runqiu,PEI Xiangjun,CUI Shenghua.Cataclastic characteristics and formation mechanism of rock mass in sliding zone of Daguangbao landslide[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(1):1-15.
[8]肖拥军,殷坤龙,柴波.含软弱夹层库岸滑坡滑带发育特征研究[J].工程地质学报,2011,19(1):65-69.XIAO Yongjun,YIN Kunlong,CHAI Bo.Development characteristics of sliding zone in reservoir slope landslides with weak intercalations[J].Journal of Engineering Geology,2011,19(1):65-69.
[9]费康,张永强,闻玮.含砾黏土压实及强度特性的实验研究[J].地震工程学报,2015,37(增刊1):12-16.FEI Kang,ZHANG Yongqiang,WEN Wei.Experimental study of compaction characteristics and strength behavior of gravelly clay[J].China Earthquake Engineering Journal,2015,37(S1):12-16.
[10]张永强.掺砾黏土力学性能试验研究[D].扬州:扬州大学,2015.ZHANG Yongqiang.Experimental study on mechanical properties of clay mixed with gravel[D].Yangzhou:Yangzhou University,2015.
[11]闻玮.掺砾黏土细观结构数值模拟[D].扬州:扬州大学,2015.WEN Wei.Numerical simulation of the microstructure of gravel mixed clay[D].Yangzhou:Yangzhou University,2015.
[12]KYAMBADDE B S,STONE K J L,BARNES G E.Discussion:index and strength properties of clay-gravel mixtures[J].Proceedings of the Institution of Civil Engineers-Geotechnical Engineering,2014,167(1):83-86.
[13]WANG Chen,ZHAN Chuanni.Gravel content effect on the shear strength of clay-gravel mixtures[J].Applied Mechanics and Materials,2011,71-78:4685
[14]中华人民共和国水利部.SL237—1999土工试验规程[S].北京:中国水利水电出版社,2007.12.