饱和黏土不排水抗剪强度各向异性的热力学本构模型研究

发布时间：2018-11-26 07:11

【摘要】：基于饱和土体TTM(Tsinghua thermodynamic soil model)热力学本构模型分析研究了饱和黏土的不排水抗剪强度各向异性问题。模型及试验研究表明:非等向或0K固结历史是引起土体强度各向异性的重要原因,固结应力比cK越小,不排水强度各向异性越大。不排水加载过程中主应力轴的方向对土体不排水抗剪强度和变形有着重要影响。一般而言,当主应力轴方向从0°旋转到90°时,土体的不排水抗剪强度逐渐下降,峰值应变却逐渐增大。此外,非等向固结会导致土体主应力与主应变的非共轴性。利用TTM理论模型,对Kaolin Clay和Boston Blue Clay的不同试验结果进行了模拟验证和预测。结果表明,TTM理论模型具有反映和预测应力引起的饱和黏土强度各向异性和应变软化等特性的能力,同时也具备精准描述主应力轴旋转等复杂路径下饱和黏土的强度和变形特征的能力。
[Abstract]:The anisotropy of undrained shear strength of saturated clay is studied based on the TTM (Tsinghua thermodynamic soil model) thermodynamic constitutive model of saturated soil. The model and experimental study show that the non-isotropic or 0K consolidation history is an important cause of soil strength anisotropy. The smaller the consolidation stress ratio cK, the greater the undrained strength anisotropy. The direction of principal stress axis plays an important role in undrained shear strength and deformation during undrained loading. Generally speaking, when the principal stress axis rotates from 0 掳to 90 掳, the undrained shear strength of the soil decreases gradually, but the peak strain increases gradually. In addition, the non isotropic consolidation will lead to the non-coaxiality of the principal stress and the principal strain of the soil. Using TTM theory model, the different test results of Kaolin Clay and Boston Blue Clay are simulated and predicted. The results show that the TTM model has the ability to reflect and predict the strength anisotropy and strain softening of saturated clay caused by stress. It also has the ability to accurately describe the strength and deformation characteristics of saturated clay under complex paths such as principal stress axis rotation.
【作者单位】：清华大学土木工程系;
【基金】：清华大学-剑桥大学-麻省理工学院低碳能源大学联盟(LCEUA)种子基金项目(2010LC002)
【分类号】：TU442

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