三轴应力状态下膨胀土增湿变形特性

 在经过改造的三轴仪上对安康击实膨胀土进行增湿变形特性试验研究。试验研究结果表明，在相同应力比的三轴应力状态下，膨胀土浸水过程中的变形为膨胀变形，变形在试样各个方向上都会产生，应力较小时，轴向和径向变形都表现为膨胀变形；应力较大时，轴向变形表现为压缩变形，而径向变形则表现为膨胀变形，但变形量都很小；土样在增湿剪切过程中以体积膨胀为主，体积变化以侧向变形为主，轴向变形较小；同时，对试验资料进行数学拟合，并对拟合公式进行验证。结果表明，试验值与计算值吻合较好。

MOISTENING DEFORMATION CHARACTERISTICS OF EXPANSIVE SOIL UNDER TRIAXIAL STRESS STATE

The stage moistening deformation tests are performed for the compacted expansive soil in Ankang using improved triaxial apparatus. The experiment shows that the deformation of the expansive soil is swelling deformation under triaxial stress state with the same stress ratio in the immersion process. The soil deformation appears in specimen¢s every orientation，the deformations in the radial and axial directions behave swelling when stress is smaller. The axial direction expresses the compresses deformation and the radial direction expresses swelling deformation when stress is greater，but the deformation is very little. In moistening shear process，the deformation of the sample is chiefly volumetric expansion and volumetric changes is chiefly lateral deformation，and the axial direction deformation is smaller；the mathematical fittings are done for the experiments data，and the fitting formula has been verified. The results show that the experimental value agrees well with calculation value.