考虑吸附水的非饱和土耗散本构关系研究

发布时间：2018-04-20 00:33

本文选题：吸附水 + 非饱和土　；参考：《岩土力学》2015年S1期

【摘要】：为了探索土水吸附特征对非饱和土力学特性的影响,根据赋存环境把土中水分为储存在毛细管内液面张力吸纳作用占主导的自由水和包裹在土颗粒周围基质静电吸着作用占主导的吸附水。通过把土颗粒基质与吸附水一起共同视为非饱和土骨架相,自由水视为液相、土中气视为气相,获得了考虑吸附水的非饱和土功表达式。根据热力学耗散理论,利用功表达式和局部热力学平衡假定,获得非饱和土在绝热变形过程中的熵流和熵产。基于热力学吸附平衡理论获得土中吸附水的吸附方程,进而提出具有实用性的吸附水土-水特征曲线。利用熵产表达式中的热力学共轭量和耗散空间的Drucker塑性公设,采用纯简化有效应力和有效吸力这一对双应力变量,建立了考虑吸附水的土水完全耦合的非饱和土弹塑性理论框架,据此获得采用净应力和吸力表示的弹塑性柔度矩阵,用于采用上述本构理论建模时理论模型与土工试验成果之间直接相互验证。
[Abstract]:In order to explore the influence of soil-water adsorption characteristics on the mechanical properties of unsaturated soils, According to the storage environment, the water in soil is divided into free water which is mainly absorbed by liquid surface tension in capillary tube and adsorbent water which is mainly adsorbed by electrostatic adsorption in the matrix surrounding soil particles. By treating the granular matrix of soil together with the adsorbed water as the skeleton phase of unsaturated soil, the free water as the liquid phase and the gas in the soil as the gas phase, the expression of the work of unsaturated soil considering the adsorbing water is obtained. Based on the theory of thermodynamic dissipation, the entropy flow and entropy production of unsaturated soil during adiabatic deformation are obtained by using the work expression and the assumption of local thermodynamic equilibrium. Based on the thermodynamic adsorption equilibrium theory, the adsorption equation of adsorbed water in soil is obtained, and a practical characteristic curve of adsorption soil and water is proposed. Using the Drucker plastic postulate of the thermodynamic conjugate quantity and dissipative space in the expression of entropy production, a pair of double stress variables, which are pure simplified effective stress and effective suction, are adopted. A theoretical framework of elastoplastic properties of unsaturated soils with fully coupled soil and water is established, and the elastic-plastic flexibility matrix expressed by net stress and suction is obtained. When the above constitutive theory is used to model, the theoretical model and the geotechnical test results are directly verified.
【作者单位】：浙江大学滨海和城市岩土工程研究中心;
【基金】：国家自然科学基金(No.51178419)
【分类号】：TU43

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