非饱和原状黄土平面应变试验研究

Experimental Study of Plane Strain of Undisturbed Unsaturated Loess

利用TS-526真三轴仪改造的平面应变仪,对不同含水率条件下原状非饱和黄土的变形和强度进行了试验研究。结果表明:在不同含水率下非饱和黄土的偏应力与轴向变形关系曲线均表现为硬化性或者强硬化性;在不同含水率下,非饱和黄土的偏应力与体积变形关系曲线存在明显拐点,在拐点之前土样表现为受剪压缩,拐点之后土样表现为受剪剪胀;土体的基质吸力随含水率的变化而变化,随着含水率的增大,基质吸力减小;非饱和黄土的抗剪强度参数随含水率的增大而减小;非饱和黄土的强度高于饱和黄土的强度。

Using plane strain apparatus of remarked TS-526 true triaxial apparatus, the deformation and shear strength of undisturbed unsaturated loess under different water contents were performed. The results show that the characters of stress-strain curves are hardening or strong hardening under the different water contents, the obvious inflection point are showed in the curves of stress-volume change, unsaturated loess is shear com- pression before inflection point, and it is shear inflation after inflection point. The matrix suction of soil varies with the change of water contents, matrix suction of soil decreased with water contents increasing. The shear strength parameters of unsaturated loess are decreasing with water contents increasing, and the strength of unsaturated loess is higher than the strength of saturated loess.