水泥稳定碎石底基层纵向开裂分析与防治

Analysis and Prevention of Longitudinal Cracking in Cement-Stabilized Crushed Stone Subbase

摘要: 通过纵向开裂路段水泥稳定级配碎石底基层原材料试验、级配分析和现场取芯厚度、强度评定、裂纹观测、施工期间荷载有限元分析、开挖试坑进行路基稳定性分析等，系统研究分析了炉慈高速公路某路面底基层施工期间出现的纵向开裂原因。研究表明：开裂路段底基层强度、厚度满足设计要求，引起本项目纵向裂缝与施工期间重型车辆荷载重复作用、路基浸水、失去地基支承有直接的关系。依托炉慈高速公路，提出了适当增大粗料用量，减少0.075 mm以下矿料用量的级配优化建议，针对本路段水泥稳定级配碎石底基层纵向开裂采取了在底基层表面加设直径：Φ10 mm双向布置100 mm × 100 mm的钢筋网片，基层采用水泥混凝土板的加固方案。本文相关分析和建议不仅服务于本项目后续施工，同时也可供同类工程参考。

Abstract: Through raw material tests, gradation analysis of the cement-stabilized graded crushed stone subbase in the longitudinally cracked section, as well as on-site coring for thickness measurement, strength evaluation, crack observation, finite element analysis of loads during construction, and excavation of test pits for subgrade stability analysis, a systematic study was conducted to analyze the causes of longitudinal cracking in the subbase of a certain pavement section of the Lunci Expressway during construction. The study shows that the strength and thickness of the subbase in the cracked section meet the design requirements, and the longitudinal cracks in this project are directly related to the repeated action of heavy vehicle loads during construction, as well as subgrade immersion and loss of foundation support. Relying on the Lunci Expressway, optimization suggestions for gradation are proposed, including appropriately increasing the dosage of coarse aggregates and reducing the dosage of mineral aggregates smaller than 0.075 mm. For the longitudinal cracking of the cement-stabilized graded crushed stone subbase in this section, a reinforcement scheme is adopted: a 10mm-diameter steel mesh arranged in a 100 mm × 100 mm bidirectional pattern is added on the surface of the subbase, and cement concrete slabs are used for the base course. The relevant analysis and suggestions in this paper not only serve the subsequent construction of this project but also provide a reference for similar projects.