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干密度和饱和度是影响非饱和膨胀土强度和变形特性的重要因素。为研究干密度和饱和度对非饱和膨胀土抗剪强度的影响,以南阳膨胀土为试验材料,对不同饱和度和干密度的南阳膨胀土的压实样进行直剪试验,得到了不同干密度及饱和度下的抗剪强度;利用滤纸法试验测得了南阳膨胀土在不同初始干密度下的土水特征曲线,并利用Fredlund-Xing方程进行全吸力范围内的拟合。通过土-水特征曲线将饱和度换算成吸力,得到了不同密度和吸力下南阳膨胀土的抗剪强度。结果表明:低吸力范围内非饱和膨胀土的强度随吸力的增大而增大;而高吸力时随着吸力的增大,土的强度变化趋势与干密度和应力大小有关,竖向压力较大和干密度较小时,强度随吸力增大而增大。
Dry density and saturation are important factors affecting the strength and deformation characteristics of unsaturated expansive soil. In order to study the influence of dry density and saturation on the shear strength of unsaturated expansive soil, Nanyang expansive soil was used as the experimental material to conduct direct shear tests on the compacted samples of Nanyang expansive soil with different saturation and dry density. Density and saturation. The soil-water characteristic curve of Nanyang expansive soils under different initial dry densities was measured by filter paper method, and the fitting was carried out by the Fredlund-Xing equation. The soil-water characteristic curve is used to convert the saturation into suction, and the shear strength of Nanyang expansive soil under different densities and suction is obtained. The results show that the strength of unsaturated expansive soil in the low suction range increases with the increase of suction force. With the increase of suction force, the strength of soil is related to the dry density and stress, Large and dry density is small, the intensity increases with suction increases.