考虑颗粒黏结效应的非饱和土水-力耦合边界面模型

Hydro-mechanical coupling bounding surface model for unsaturated soils considering bonding effect of particles

颗粒间黏结效应对非饱和土水-力耦合特性影响显著,建立考虑黏结效应的非饱和土本构模型,对于准确分析非饱和土的水-力耦合特性具有重要意义。在边界面塑性理论框架下,建立了一个同时考虑基质吸力、饱和度和孔隙结构对黏结效应影响的非饱和土水-力耦合模型。对于力学部分,选取有效应力与黏结变量作为本构变量,建立了黏结变量与e/es之间的关系,并基于边界面塑性理论对非饱和土变形特性进行描述;对于水力部分,建立了考虑变形影响的水力滞后土-水特征曲线方程。利用膨润土-高岭土混合土、重塑高岭土的试验结果对所建立的模型进行了参数标定和模型验证,结果表明,所建立模型能够合理预测非饱和土的水-力耦合特性。

The interparticle bonding effect has a significant influence on the hydro-mechanical coupling characteristics of unsaturated soils. Establishing a constitutive model for unsaturated soils considering the bonding effect is of great significance for accurately analyzing their hydro-mechanical coupling characteristics. Based on the theory of bounding surface plasticity, a hydro-mechanical coupling model for unsaturated soils considering the influences of matric suction, degree of saturation and pore structure on the bonding effect is established. For the mechanics part, the effective stress and bonding variable are selected as the constitutive variables, the relationship between the bonding variable and e/es is established, and the deformation characteristics of unsaturated soils are described based on the theory of bounding surface plasticity. For the hydraulic part, a hydraulic hysteresis soil-water characteristic curve equation considering the effect of deformation is established. The experimental results of bentonite-kaolin mixture and reconstituted kaolin are used for parameter calibration and model verification of the proposed model. The results show that the proposed model can reasonably predict the hydro-mechanical coupling characteristics of unsaturated soils.