A system for preparing soil specimens subjected to drying–wetting cycles while under vertical confining pressures was introduced with clayey soil specimens subjected to different drying–wetting histories, and then the relative performance was tested using consolidated undrained triaxial shear tests. Meanwhile, their soil water retention properties were also measured. The experimental results indicated that drying–wetting cycles lead to a rise in the matric suction for soil with a high moisture content and a decrease in matric suction for soil with a low moisture content. Partly owing to the higher pore water pressure, peak shear strength reduces gradually during drying–wetting cycles. The impacts of drying–wetting cycles on the hydromechanical properties of soil specimens during the first cycle are greater than those during the second and third cycles, as the highest matric suction of soil occurs during the first cycle. The vertical confining pressure is shown to limit the impact of drying–wetting cycles on the hydromechanical properties of soil effectively because of its restricting effects on the volumetric deformation of soil during the cycles.

中文翻译：

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土壤在干湿循环和垂直围压下的力学行为

介绍了一种用于在垂直围压下进行干湿循环的土样制备系统，其中粘土样经历了不同的干湿历史，然后使用固结不排水三轴剪切试验测试了相关性能。同时，还测量了它们的土壤保水性能。实验结果表明，干湿循环导致高含水量土壤的基质吸力增加，而低含水量土壤的基质吸力降低。部分由于较高的孔隙水压力，峰值剪切强度在干湿循环期间逐渐降低。干湿循环在第一个循环中对土样流体力学性质的影响大于在第二个和第三个循环中的影响，因为土壤的最高基质吸力发生在第一个循环中。垂直围压被证明可以有效地限制干湿循环对土壤流体力学特性的影响，因为它对循环过程中土壤的体积变形具有限制作用。