粉质砂土的土-水特征及一维应力变形试验研究

浅层非饱和土的力学特性与其土-水特征密切相关,研究自重应力作用下土体的土-水特征曲线及一维应力变形对于边坡、基坑等工程的稳定性分析具有重要意义。采用应力相关的压力板仪对西南某地区的粉质砂土进行了干燥试验及k₀固结试验。结果表明:在较低的竖向应力状态下,应力大小变化对粉质砂土的土-水特征曲线影响不大;在一定的净竖向应力状态下,粉质砂土的体积应变随吸力的增加呈线性增大;在一定的吸力状态下,粉质砂土的k₀固结变形是非线弹性的,净竖向应力越大,土体的体积应变越大,孔隙比越小。

Experimental Study on the Soil-Water Characteristics and Deformation of Silty Sand under 1-D Stress

The mechanical properties of unsaturated soils in superficial layer is closely related with soil water characteristics. Researching on the soil water characteristics under geostatic stress and the deformation under 1 -D stress state is important for stability analysis in slope and foundation pit excavation. To investigate the effect of 1-D stress and suction on the deformation of silty sand in southwest China, we carried out drying tests and consolidation tests by using a k 0 stress controllable pressure plate apparatus. Test results show that given low vertical stress state, the stress variation in a small range has little influence on soil-water characteristic curve. Under certain net vertical stress, the volumetric strain of silty sand increases linearly with the increase of suction. Under certain suction, the consolidation deformation under k0 stress is non-linearly elastic. As net vertical stress increases，the volumetric strain increases and the void ratio reduces.