Research on Subgrade Splicing Construction Technology and Differential Settlement Control Technology in Highway Reconstruction and Expansion Projects
公路改扩建工程路基拼接施工技术及沉降差异控制技术研究

摘要

随着国内交通运输路网流量持续激增，早期建成的二级、一级及高速公路逐渐出现通行能力不足、服 务水平下降、荷载适配性不足等问题，公路改扩建成为提升道路通行能力、完善区域路网结构、适配交通发 展需求的重要手段。路基拼接作为公路改扩建工程的核心重难点施工内容，新旧路基土体固结程度、地基刚度、 压缩特性存在天然差异，施工过程极易产生不均匀沉降，诱发纵向裂缝、路面错台、路基局部塌陷等常见道 路病害，严重影响工程质量与道路长期运营安全。本文结合公路改扩建工程施工特性，系统剖析新旧路基差 异沉降的产生机理、内外影响因素及工程危害，详细阐述基底处理、台阶开挖、分层填筑、土工加筋、防水 排水等路基拼接关键施工工艺。同时从地基预处理、精细化填筑压实、结构加筋加固、水害综合治理、全过 程动态监测、施工质量管控等多角度，构建完善的差异沉降控制技术体系。研究成果可有效降低新旧路基沉 降差值，提升路基整体协同受力性能，规避拼接部位结构性病害，为同类公路改扩建路基施工、沉降治理及 质量提升提供可靠的工程技术参考。

Abstract

With the continuous rapid increase in traffic volume on China’s transportation road network, secondary highways, first-class highways, and expressways built in the early stage have gradually shown problems such as insufficient traffic capacity, declining service level, and inadequate load adaptability. Highway reconstruction and expansion have become important means to improve road capacity, optimize regional road network structure, and meet the needs of traffic development. As a core and difficult construction task in highway reconstruction and expansion projects, subgrade splicing involves natural differences in consolidation degree, foundation stiffness, and compression characteristics between new and existing subgrade soils. During construction, uneven settlement is highly likely to occur, inducing common road diseases such as longitudinal cracks, pavement faulting, and local subgrade collapse, which seriously affect project quality and long-term road operation safety. Based on the construction characteristics of highway reconstruction and expansion projects, this paper systematically analyzes the formation mechanism, internal and external influencing factors, and engineering hazards of differential settlement between new and existing subgrades, and elaborates on key subgrade splicing construction processes, including foundation treatment, bench excavation, layered filling, geosynthetic reinforcement, waterproofing, and drainage. Meanwhile, a complete differential settlement control technical system is constructed from multiple perspectives, including foundation pretreatment, refined filling and compaction, structural reinforcement, comprehensive water damage control, whole-process dynamic monitoring, and construction quality control. The research results can effectively reduce the settlement difference between new and existing subgrades, improve the overall coordinated bearing performance of the subgrade, prevent structural diseases at splicing sections, and provide reliable engineering technical reference for subgrade construction, settlement treatment, and quality improvement in similar highway reconstruction and expansion projects.