陕西蒲城Q2黄土湿陷变形特性研究

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。

Collapsible deformation properties of Q2 loess in Pucheng of Shaanxi province

A series of collapsibility tests on Q2 loess of Pucheng power plant in Shaanxi province under 1D and 3D stress conditions were conducted using GDG high pressure oedometer and unsaturated collapsible triaxial apparatus. Under 1D stress condition, the collapsibility of Q2 loess is moderate or weak. The maximum coefficient of collapsibility decreases with the increase of depth. The Q2 loess is not collapsible under low pressure, but it is possibly collapsible under high pressure. The collapsibility of Q2 loess layer is stronger than that of ancient layer. The collapsibility sensibility of Q2 loess is weaker. Large-scale projects should use actual pressure to evaluate collapsibility of Q2 loess. Under 3D stress condition, curves of collapsible strain in terms of quantity of wetting are divided into three stages: the collapsible strain increasing slightly, the collapsible strain increasing rapidly and the collapsible strain being almost unchanged. The influences of net confining pressure, deviatoric stress and suction, especially the latter two, on the collapsible strain during the process of wetting are obvious. The collapsible volumetric strain increases with the increase in the collapsible deviatoric strain and the relationship is almost linear.