In-flight cone penetration tests (CPTs) have been conducted extensively to characterize centrifuge models of dry and saturated soils, but only a limited number of studies have focused on unsaturated soils. This paper presents centrifuge modeling of CPTs conducted on unsaturated clayey sand models prepared at various hydraulic conditions including as-compacted, wetting (rainfall) and drying (evaporation). The objectives of this study were to evaluate effects of stress level induced by centrifuge acceleration and to investigate the impact of hydraulic processes on the cone tip resistance (q_c). Results shows that variations of q_c with depth obtained from different centrifugal acceleration are in very good agreement and similarity of q_c and water content distribution in centrifuge models is validated. In addition, it was found that matric suction has greater impact on the q_c than total vertical stress. The CPTs performed on clayey sand show that the cone tip resistance increases as the degree of saturation decreases under different hydraulic conditions. A correlation between the cone tip resistance and degree of saturation is applicable to both wetting and drying processes. The CPT results and in-flight water content measurements provide a good indication of strength and stiffness change in unsaturated soil subject to changes in hydraulic conditions.

中文翻译：

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不同水力条件下非饱和粘土砂锥入度试验的离心模拟

飞行锥入度测试 (CPT) 已被广泛用于表征干燥和饱和土壤的离心模型，但只有少数研究集中在非饱和土壤上。本文介绍了对在各种水力条件下制备的不饱和粘土砂模型进行的 CPT 离心建模，包括压实、润湿（降雨）和干燥（蒸发）。本研究的目的是评价通过离心加速度引起的应力水平的影响，并调查液压过程对锥尖电阻（冲击q _Ç）。结果显示，变体q _Ç从不同离心加速度得到具有深度是非常良好的一致性和相似性q _Ç并验证了离心机模型中的含水量分布。此外，发现基质吸力对q _{c 的}影响大于总垂直应力。在粘土砂上进行的 CPT 表明，在不同的水力条件下，锥尖阻力随着饱和度的降低而增加。锥尖电阻和饱和度之间的相关性适用于润湿和干燥过程。CPT 结果和飞行中的含水量测量结果很好地表明了受水力条件变化影响的非饱和土壤的强度和刚度变化。