Abstract: Firstly，the usual defects among the many roadbed widening projectsis analysed，andthen,theIeasonisfound Out for the breakage of road surface fabric which infected by the asynchronous distortion and the difference of settlement of new and old roadbed，finally，this result is confirmed by the field testing on the project of roadbed widening in chongqing，

Key words: widening of roadbed, asynchronous distortion, instability, settlement

摘要： 笔者对路基拓宽工程中常见病害进行了分析，剖析了新旧路基不协调变形的特征规律和沉降差异对路面结 构损坏的原因，并以重庆地区典型路基拓宽工程为试验依托背景．

关键词: 路基拓宽, 不协调变形, 失稳, 沉降