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.
引文
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