Zhu Rui, Xing Wei, Zhou Feng, Liu Gang, Chang Wei, Zhang Feng, Zhou Xiaolong
School of Transportation Engineering, Nanjing Tech University, Nanjing, 211816, China.
State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, 100048, China.
Heliyon. 2024 Jul 9;10(14):e34374. doi: 10.1016/j.heliyon.2024.e34374. eCollection 2024 Jul 30.
Silty soil was widely used as filling soil materials for the replacement of expansive soil in cold regions. This paper presents a straightforward approach for the effects of wetting-drying-freezing-thawing cycles on mechanical behaviors of silty soil and expansive soil by laboratory tests. The results showed that the silty soil and expansive soil after 7th wetting-drying-freezing-thawing cycles presented the decreases of elastic modulus, failure strength, cohesion and angel of internal friction by 8.9 %∼12.0 %, 7.7 %∼9.0 %, 7.9 %, 4.5 % and 17.6 %∼37.0 %, 20.5 %∼29.4 %, 43.2 %, 13.0 %, respectively, indicating that wetting-drying-freezing-thawing cycles had little impact on mechanical property of silty soil and a great influence on that of expansive soil. Among them, the mechanical property attenuation ratio in the first three wetting-drying-freezing-thawing cycles accounted for over 90 % of the total. In the meantime, the micro-structure damage, surface crack characteristics and grain size distribution variations of expansive soil were all more significantly than these of silty soil exposed to wetting-drying-freezing-thawing cycles, which brought insight into the causes of the differences in mechanical properties for silty soil and expansive soil. It is found that the silty soil properties were more stable than expansive soil properties, and the silty soil is very effective for replacing the expansive soil below canal structures in cold regions.
粉质土被广泛用作寒冷地区替代膨胀土的填土材料。本文通过室内试验提出了一种直接的方法来研究干湿冻融循环对粉质土和膨胀土力学行为的影响。结果表明，经过7次干湿冻融循环后，粉质土和膨胀土的弹性模量、破坏强度、黏聚力和内摩擦角分别降低了8.9%∼12.0%、7.7%∼9.0%、7.9%、4.5%和17.6%∼37.0%、20.5%∼29.4%、43.2%、13.0%，表明干湿冻融循环对粉质土力学性质影响较小，对膨胀土力学性质影响较大。其中，前三次干湿冻融循环中力学性质衰减率占总衰减率的90%以上。同时，膨胀土在干湿冻融循环作用下的微观结构损伤、表面裂纹特征和粒度分布变化均比粉质土更为显著，这为粉质土和膨胀土力学性质差异的原因提供了深入认识。研究发现，粉质土性质比膨胀土性质更稳定，粉质土对于替代寒冷地区渠道结构下方的膨胀土非常有效。
