纯主应力旋转条件下饱和黏土累积变形的热力学模型分析

发布时间：2018-04-11 13:54

本文选题：主应力旋转 + 非共轴性　；参考：《岩土工程学报》2015年09期

【摘要】：不同于岩土弹塑性模型和经验回归模型,提供了一个基于颗粒固体流体动力学的热力学本构模型。该模型通过对岩土颗粒固体的弹性弛豫和颗粒熵运动等耗散机制的定量描述,可以模拟土体的非线性硬化、软化等宏观力学行为,尤其适用于主应力旋转土体累积塑性应变的模拟。纯主应力旋转条件下杭州黏土的模拟结果表明:即使不改变土体的主应力大小,纯主应力方向的旋转依然会引起土体的非弹性变形的积累。在主应力旋转过程中,土体的应变方向与应力方向并不一致,存在明显的非共轴现象。并且应变峰值的出现明显落后于应力峰值,应力应变关系曲线存在较大的滞回圈,表明纯主应力旋转过程中也存在能量耗散,并非完全弹性过程。模型分析结果符合现有的试验结论。
[Abstract]:A thermodynamic constitutive model based on particle solid fluid dynamics is provided, which is different from the geotechnical elastoplastic model and the empirical regression model.The model can simulate the macroscopic mechanical behaviors of soil such as nonlinear hardening and softening by quantitatively describing the dissipation mechanism of rock and soil particles such as elastic relaxation and particle entropy motion.It is especially suitable for the simulation of accumulated plastic strain of principal stress rotating soil.The simulation results of Hangzhou clay under the condition of pure principal stress rotation show that even if the principal stress of the soil is not changed, the rotation of the direction of the pure principal stress will still lead to the accumulation of inelastic deformation of the soil.In the process of principal stress rotation, the strain direction of soil is not consistent with the stress direction, and there is obvious non-coaxial phenomenon.The peak value of strain lags behind the peak of stress obviously, and the curve of stress-strain relationship has a large hysteresis loop, which indicates that there is energy dissipation in the process of pure principal stress rotation, which is not a complete elastic process.The results of the model analysis are in accordance with the existing experimental conclusions.
【作者单位】：清华大学土木工程系;中铁二院工程集团有限责任公司;
【基金】：清华-剑桥-麻省理工学院三校低碳大学联盟种子基金项目(2010LC002) “973”计划课题(2013CB036404)
【分类号】：TU43

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