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利用GDG型高压固结仪和自行研制的非饱和土湿陷三轴仪对陕西蒲城电厂Q2黄土一维和三维应力状态下的湿陷性进行了试验研究,分析了Q2黄土的湿陷特性。试验结果表明:一维状态下,Q2黄土以中等和弱湿陷为主,峰值湿陷系数随深度增加而变小,常规压力下不湿陷的Q2黄土在高压力下可能湿陷,Q2地层中黄土层的湿陷性总体上强于古土壤层,湿陷的敏感性较弱,大型工程宜用实际压力评价湿陷性。三维状态下,湿陷应变随浸水量的变化曲线可以近似分为3段,即湿陷应变缓慢增加段、快速发展段和基本不变段;浸水前的吸力、净围压、偏应力对湿陷过程均有影响,且偏应力和吸力的影响更明显;三轴浸水过程湿陷体应变随湿陷轴应变的增加而增大,几乎是一条直线,体现了湿陷变形的特殊性。
The collapsibility of Q2 loess in Pucheng Power Plant in Shaanxi Province under one-dimensional and three-dimensional stress was studied by means of GDG high-pressure consolidation instrument and the unsaturated soil collapsible triaxial apparatus developed by ourselves. The collapsibility characteristics of Q2 loess were analyzed. The results show that the Q2 loess is dominated by moderate and weak collapsibility in one dimension, and the peak collapsibility decreases with increasing depth. The undrained Q2 loess under normal pressure may collapse under high pressure. The Q2 formation The collapsibility of middle loess layer is generally stronger than that of paleosol layer, and its sensitivity to collapsing is weak. For large scale projects, collapsibility should be evaluated by actual pressure. In the three-dimensional state, the curve of the collapsing strain with the water immersion amount can be roughly divided into three sections, that is, the slowly increasing section, the rapid developing section and the basic invariable section of the wetting strain; the pre-immersion suction, the net confining pressure and the deviatoric stress The effect of deviatoric stress and suction is more obvious. The strain of the collapsible body increases with the increase of the strain of the wet-collapsed shaft, which is almost a straight line, which reflects the particularity of the collapsible deformation.