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以一种非膨胀性黏土为试验材料,对孔隙比相近的非饱和压实试样和预固结试样进行一系列等吸力控制下的等向压缩试验和三轴剪切试验,研究了制样方法对非饱和土的压缩特性和剪切特性的影响。由等吸力等向压缩试验结果表明:初始孔隙比相近的预固结样和压实样在等向净应力20 k Pa条件下进行等吸力平衡,平衡过程中预固结试样的孔隙比明显减小而压实样的变化不大;其原因是两种试样的初始吸力和土结构存在差异。此外,预固结样和压实样在吸力150 k Pa条件下,预固结样的含水率随着等向净应力的增大而减小,而压实样的含水率几乎不变。上述变形特性可用SFG弹塑性模型说明。在净围压和吸力相同条件下对剪切前孔隙比相同的两种试样进行了三轴剪切试验,试验结果表明:在剪切前的密度、剪切时的吸力和净围压相同条件下,预固结样的偏应力–应变曲线和强度明显高于压实试样的曲线和强度。其原因可用两种试样的孔隙尺寸分布不同来解释。
Based on a series of isotropic compression tests and triaxial shear tests of unsaturated cements and preconsolidated samples with similar void ratio using a non-expansive clay as the test material, Influence of Sample Method on Compressive and Shear Properties of Unsaturated Soils. The results of isostatic compression tests show that the equal-suction equilibrium is achieved under the condition of equal net stress of 20 kPa with the initial void ratio of the pre-consolidation and compaction samples. The void ratio of the pre-consolidated sample during the equilibrium process is obviously The reason for the decrease is that the initial suction and soil structure of the two samples are different. In addition, the pre-consolidation and compaction samples under the suction of 150 kPa conditions, the pre-consolidation-like water content decreases with increasing net isotropic stress, while the compacted water content is almost unchanged. The above deformation characteristics can be described by the SFG elastoplastic model. Under the same conditions of net confining pressure and suction, triaxial shear tests were carried out on two specimens with the same porosity before shearing. The results show that the density before shearing, the suction at shearing and the net confining pressure are the same Under the conditions, the pre-consolidation-like deviatoric stress-strain curve and strength are significantly higher than those of compacted samples. The reason for this can be explained by the difference in pore size distribution between the two samples.