干湿循环条件下粉质黏性石灰改良土的劣化机制研究
A Study on the Deterioration Mechanism of Silty Cohesive Lime Improved Soil under Dry-Wet Cycle Conditions

粉质黏性土地区的公路路基为预防多次干湿循环造成路基软化，通常采用掺加石灰进行粉质粘性土性质改良，不同地区的粉质黏土其物理性质不一致，其最佳掺灰量也不一致。文章以绍兴二环西路智慧快速路改造工程为依托，结合室内干湿循环试验与数值分析着重对粉质黏性改良土含灰率进行分析，探讨不同压实系数、不同掺灰量石灰改良土在干湿循环条件下的强度分析。试验研究结果表明：1) 在粉质黏性土中掺入石灰量可有效抵制干湿循环的影响；2) 石灰改良土中的石灰含量低于2%其改良效果不明显，石灰含量8%改良土干湿循环条件下其强度最大；3) 在干湿循环条件下石灰掺入量与改良土强度之间具有一定的离散性；4) 在干湿循环条件下压实系数90%的改良土强度低于压实系数95%的改良土，压实系数越高越不易被破坏。
In order to prevent roadbed softening caused by multiple wet and dry cycles, the addition of lime is usually used to improve the properties of powdery cohesive soil in highway embankments in powdery cohesive soil areas. The physical properties of silty clay in different regions are inconsistent, and the optimal amount of lime added is also inconsistent. The article is based on the renovation project of Shaoxing Second Ring West Road Smart Expressway, combined with indoor dry-wet cycle tests and numerical analysis, focusing on the analysis of the ash content of silty cohesive improved soil, and exploring the strength analysis of lime improved soil with different compaction coefficients and ash content under dry-wet cycle conditions. The experimental research results show that: 1) The addition of lime in silty cohesive soil can effectively resist the influence of dry-wet cycles; 2) If the lime content in lime improved soil is less than 2%, the improvement effect is not significant, and the strength of the improved soil with a lime content of 8% is the highest under dry-wet cycle conditions; 3) There is a certain degree of discreteness between the amount of lime added and the strength of the improved soil under dry-wet cycle conditions; 4) Under dry-wet cycle conditions, the strength of improved soil with a compaction coefficient of 90% is lower than that of improved soil with a compaction coefficient of 95%, the higher the compaction coefficient, the less likely it is to be destroyed.