At present, in the construction process of highway subgrades, builders often encounter the phenomenon of stress concentration caused by an insufficient subgrade soil layer, which causes early damage to the pavement structure. In engineering, a common technique is the use of lime to treat bad subgrade sections to improve the soil-based elastic modulus. The effect of the treatment has been recognized by designers in the industry.^1–3 However, factors such as lime treatment, roadbed depth, and reasonable thickness of each layer of pavement structure have great influence on the pavement stress and strain design index.^4–6 So far, little research has been conducted on the relationship between the depth of lime-treated soft soil subgrades and the internal stress of asphalt pavement structures. The lime-treated soft soil subgrade in the actual project is blind and random. For example, during the design and construction, regardless of the thickness of the pavement structure layer of the asphalt, a treatment depth is selected according to the designer’s experience to improve the subgrade soil. As a result, the rebound modulus of the top of the road is too small, and the pavement structure is easily damaged. If the processing depth is too great, it increases costs. Therefore, this study investigated the relationship between subgrade depth treated with lime and pavement structure according to the characteristics of the pavement structure. It is particularly important to determine the reasonable depth of lime-treated soil to guide design and construction.^7–9 Therefore, article takes the Changchun–Fuyu Expressway reconstruction and expansion project as an example. Through indoor and outdoor experiments and finite-element (FE) numerical simulation analysis, we studied the influence of the depth of lime treatment for the internal stress and strain of the pavement structure and proposed a reasonable thickness of the pavement structure of each layer for analysis by using gray correlation theory.^10–12 The results of this study hold great practical significance for improving design specifications, ensuring road engineering quality, and saving engineering construction costs.

中文翻译：

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基于路基土改良灰色关联分析的高速公路路面结构合理厚度设计

目前，在公路路基施工过程中，建设者经常遇到因路基土层不足而引起应力集中的现象，导致路面结构早期损坏。在工程中，常用的技术是利用石灰处理不良路基地段，以提高土基弹性模量。处理效果得到了业内设计师的认可。^1~3然而，石灰处理、路基深度、路面结构各层合理厚度等因素对路面应力应变设计指标影响较大。^4-6迄今为止，关于石灰处理软土路基深度与沥青路面结构内应力关系的研究还很少。实际工程中的石灰处理软土路基是盲目的、随意的。例如，在设计和施工时，无论沥青路面结构层的厚度如何，都根据设计者的经验选择处理深度来改善路基土。导致路顶回弹模量过小，路面结构容易损坏。如果加工深度太大，则会增加成本。因此，本研究根据路面结构的特点，探讨石灰处理路基深度与路面结构的关系。确定石灰处理土的合理深度对于指导设计和施工尤为重要。^7-9因此，本文以长扶高速公路改扩建工程为例。通过室内外试验和有限元数值模拟分析，研究了石灰处理深度对路面结构内应力、应变的影响，提出了各层路面结构的合理厚度进行分析。利用灰色关联理论。^10-12本研究成果对于提高设计规范、保证道路工程质量、节约工程建设成本具有重要的现实意义。