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通过室内试验模拟土体季节性的干湿和冻融交替变化,采用直剪试验测试了原状黄土经干湿和冻融循环作用后的抗剪强度及抗剪强度参数的变化,并进行了直剪后试样的易溶盐总量测定.结果表明:干湿和冻融循环作用对原状黄土物理力学性质影响极大,是造成黄土边坡破坏的主要因素.随着干湿循环次数的增加,试样的抗剪强度逐渐减小,黏聚力逐渐减小,内摩擦角先增加,后逐渐趋于稳定,盐分迁移现象明显,土样下部易溶盐含量逐渐减少,上部易溶盐含量逐渐增加,并且试样的质量损失逐渐增加;随着冻融循环次数的增加,试样的抗剪强度逐渐减小,黏聚力逐渐增大最后趋于稳定,而内摩擦角和盐分迁移现象不明显.
The seasonal variations of dry-thaw and freeze-thaw cycles of soils were simulated by laboratory tests. The changes of shear strength and shear strength parameters of undisturbed loess after wet-dry and freeze-thaw cycles were tested by direct shear tests. The results showed that the wet-dry and freeze-thaw cycles had a great influence on the physical and mechanical properties of intact loess and were the main factors that caused the failure of loess slopes. With the increase of the number of wet and dry cycles , The shear strength of the sample gradually decreases, the cohesion force decreases gradually, the internal friction angle first increases, then gradually stabilizes, the phenomenon of salt migration is obvious, the content of soluble salt in the lower part of soil sample decreases gradually, the content of upper soluble salt With the increase of the number of freeze-thaw cycles, the shear strength of the sample decreases gradually, cohesion gradually increases and finally stabilizes, while the internal friction angle and salt migration Not obvious.