不同三轴应力条件下湿陷性黄土增湿变形特性研究

Research on wetting and collapsible deformation characteristics of collapsible loess under different triaxial stress conditions

复杂应力条件下黄土的湿陷变形特性研究是黄土力学的关键问题。黄土在实际工程中常承受不同的主应力条件,本文把轴对称黄土的围压及围压与轴压应力比调节为为定值K,进行了不同围压和应力比的黄土增湿至饱和浸水三轴试验:测试分析了不同应力比K值下黄土增湿孔隙比、增湿体应变随球应力的变化规律;定量分析了球应力与湿陷体应变、剪应力与湿剪应变之间的变化规律;揭示了黄土湿陷变形的应力界限条件。最后依据三轴应力条件下湿陷试验结果,给出了湿陷性黄土的湿陷变形计算表达式,为三轴应力条件下对黄土地基湿陷性变形评价提供了参考。

The study of collapsibility and deformation characteristics of loess under complex stress is the key problem of loess mechanics. Loess is often subjected to different principal stress conditions in practical engineering. In this paper, by controlling the axial symmetry loess of confining pressure and confining pressure and axial compressive stress ratio as constant value, triaxial tests from wetting to saturated immersion of loess with different confining pressures and stress ratios were carried out. The variation laws of wetting void ratio and wetting volume strain on spherical stress, spherical stress and collapsible strain, shear stress and wet shear strain were tested and analyzed, and the stress limit conditions of collapsible deformation of loess were revealed.Furthermore, based on the results of the collapsible test under triaxial stress, the expression of the collapsible deformation of the collapsible loess is proposed, which provides a reference for the evaluation of the collapsible deformation of the collapsible loess foundation under triaxial stress condition.