Research on Disease Treatment at the Joint between Existing and New Subgrades in Old Road Widening and Reconstruction
旧路加宽改造中新旧路基结合部病害处理研究

摘要

在旧路加宽改造工程中，新旧路基结合部是道路结构的薄弱环节，受新旧路基固结状态差异、施工工艺不足、水 文地质影响等因素，极易产生不均匀沉降、路面开裂、错台、唧泥等病害，严重影响道路通行安全与使用寿命。本文 系统梳理旧路加宽路基结合部常见病害类型，深入剖析病害形成机理，针对性研究台阶开挖、加筋补强、地基加固、 分层压实等核心处治技术，结合工程施工要点提出全过程病害防控方案。研究结果表明，通过标准化拼接施工、优化 填料配比、强化排水体系与动态沉降监测，可有效降低结合部变形差，提升路基整体稳定性，为同类旧路加宽改造工 程提供技术参考。 

Abstract

 In old road widening and reconstruction projects, the joint between the existing and new subgrades is a weak part of the road structure. Affected by differences in consolidation conditions between the existing and new subgrades, inadequate construction techniques, hydrogeological conditions, and other factors, defects such as uneven settlement, pavement cracking, faulting, and mud pumping are highly likely to occur, seriously affecting traffic safety and service life. This paper systematically reviews common types of diseases at subgrade joints in old road widening projects, deeply analyzes their formation mechanisms, and carries out targeted research on core treatment technologies such as step excavation, reinforcement, foundation strengthening, and layered compaction. Combined with key construction points, a whole-process disease prevention and control scheme is proposed. The research results show that standardized splicing construction, optimized filler proportioning, strengthened drainage systems, and dynamic settlement monitoring can effectively reduce deformation differences at the joint, improve the overall stability of the subgrade, and provide technical reference for similar old road widening and reconstruction projects.