College of Civil Engineering and Architecture, Dalian University, Dalian, China.
School of Civil and Architectural Engineering, East China University of Technology, Nanchang, China.
PLoS One. 2024 Aug 26;19(8):e0309443. doi: 10.1371/journal.pone.0309443. eCollection 2024.
In Northwest China, the highway infrastructure often faces challenges due to the widespread presence of subgrade soil. This soil undergoes significant changes in performance under cyclic loading and freeze-thaw cycles. To effectively design and construct highways in these regions, it is crucial to understand the impact of various factors on the deformation characteristics and mechanical properties of subgrade soil. This study aims to investigate the influence of freeze-thaw cycles, water content, confining pressure, and loading rate on the deformation behavior and mechanical properties of subgrade soil under cyclic loading conditions. Experimental tests were conducted to analyze the deformation characteristics and mechanical properties of the subgrade soil. The test results revealed the following: 1) Dynamic loading leads to a noticeable decrease in the strength of subgrade soil, resulting in a softening effect on the stress-strain curve. The cumulative strain of the soil is positively correlated with the number of freeze-thaw cycles and water content, while negatively correlated with confining pressure. The final cumulative strain remains below 1%. 2) The failure stress of subgrade soil decreases exponentially with an increase in freeze-thaw cycles, dropping from 224.52 kPa to 196.76 kPa. 3) An increase in water content linearly decreases the failure stress of subgrade soil, ranging from 377.1 kPa to 151.5 kPa. 4) Confining pressure exhibits a linearly increasing relationship with the failure stress of subgrade soil, ranging from 151.6 kPa to 274.5 kPa. 5) The failure stress of subgrade soil demonstrates a linear increase with the loading rate, ranging from 200.46 kPa to 210.62 kPa. These findings provide valuable insights for the design and construction of highways in seasonal frozen areas. They also offer guidance for preventing and mitigating subgrade freeze-thaw issues in the future.
在中国西北地区，由于广泛存在的路基土，公路基础设施经常面临挑战。这种土壤在循环荷载和冻融循环下会发生显著的性能变化。为了在这些地区有效地设计和建造公路，了解各种因素对路基土变形特性和力学性能的影响至关重要。本研究旨在研究冻融循环、含水量、围压和加载速率对循环荷载条件下路基土变形特性和力学性能的影响。进行了实验测试来分析路基土的变形特性和力学性能。测试结果表明：1）动荷载会导致路基土强度明显降低，对应力-应变曲线产生软化效应。土壤的累积应变与冻融循环次数和含水量呈正相关，与围压呈负相关。最终累积应变仍低于 1%。2）路基土的破坏应力随冻融循环次数的增加呈指数下降，从 224.52 kPa 降至 196.76 kPa。3）含水量的增加会线性降低路基土的破坏应力，从 377.1 kPa 降至 151.5 kPa。4）围压与路基土破坏应力呈线性增加关系，从 151.6 kPa 增至 274.5 kPa。5）路基土的破坏应力随加载速率呈线性增加，从 200.46 kPa 增至 210.62 kPa。这些发现为季节性冻土地区公路的设计和施工提供了有价值的参考。它们还为未来预防和减轻路基冻融问题提供了指导。
