盐溶液饱和黏土的力学行为模拟

Modeling mechanical behaviors of clayey soil saturated by salt solution

由于黏性土表面带有丰富的负电荷,孔隙水溶液化学状态的变化对黏性土的物理力学特性存在明显影响。随着化学-力学耦合的相关岩土工程问题日益突出,进行有效的化学-力学耦合行为的数值分析评价显得尤为重要。因此,建立一个简单有效的考虑化学-力学耦合的本构模型是非常关键的。基于传统的修正剑桥模型,提出了一个简单的化学-力学耦合模型。该模型采用渗透吸力π描述孔隙水的化学状态,建立了前期屈服应力,临界状态线斜率M和弹性刚度与渗透吸力π之间的关系式,从而实现了模型对盐溶液饱和黏性土的变形和强度特性的有效模拟。通过与试验数据的对比和分析,说明该模型能有效地模拟孔隙盐溶液饱和黏性土的等向压缩行为、K_0状态下压缩行为以及K_0状态下化学-力学循环加载行为。此外,通过对黏性土三轴压缩试验的模拟,说明该模型能反映黏性土三轴应力状态下的基本力学特征。

Due to the abundant negative charge existing on the surface of clayey soil particles, pore solution has significant influence on the physical and mechanical properties of clayey soils. The demanding geotechnical applications necessitates an effective numerical analysis of the detailed problems of chemo-mechanical coupling. Therefore, it is very important to develop a constitutive chemo-mechanical model on clayey soil saturated by salt solution. Based on the modified Cam clay model, a simple chemo-mechanical constitutive model is proposed. In the proposed model, the osmotic suction is adopted to describe the chemical state of pore solution in clayey soil. Formulas are presented to relate the pre-consolidated stress, the slope of critical state line M and elastic modulus to the osmotic suction. The comparison between simulated results and experimental data demonstrates that the proposed model is able to capture the isotropic compression, compression behavior for clayey soil saturated bysalt solution. The proposed model also can reproduce the response of clayey soil sample subjected to chemical and mechanical alternative loading. The simulated result for triaxial compression test also implies that the proposed model can capture the fundamental features of triaxial compression response of clayey soil.