考虑黄土结构性变化的地基增湿压缩变形分析

通过湿陷性黄土的侧限压缩试验,按照损伤力学复合体理论,研究了压缩应力应变曲线及其切线压缩模量的变化规律,提出了能够考虑加载及增湿耦合作用的结构损伤比,并在考虑实际地基浸水和附加应力变化的耦合作用下,建立了切线压缩模量随含水量和附加应力连续变化的函数。发现切线压缩模量随压应力的增大而减小,随含水量的升高而降低;压缩应力和增湿作用下的结构损伤性较压硬性更加突出,加荷和增湿作用过程就是黄土结构的损伤过程。基于黄土的结构损伤比,给出了地基土压缩模量随含水量和压缩应力连续变化的函数,提出的地基沉降验算方法是评价湿陷性黄土地基可能湿陷量的一条有效途径。

Analysis of moistening and compression deformation of loess considering soil structure variations

Based on the analysis of large amount of confined compression test data of collapsed loess,the compressive stress-strain curves and the tangent compression modulus are studied.With the composite damage theory of soils,a damage ratio of collapsed loess is proposed,with the coupled action of increased compression stress and water content considered.The constitutive variation of the compression tangent modulus of collapsed loess is established as a function of compression stress and water content.It is found that tangent compression modulus decreases with increasing of compression stress and water content;the damage of loess structure subjected to compression stress is more pronounced than its compaction,and the gradual tangent modulus decrease reflects the damage of the loess structure.Based on the damage ratio of the loess structure,the change in compression modulus of collapsed loess can be expressed as a function of the compression stress and water content.The proposed method of evaluating the potential settlement of loess foundation is an effective approach.