在高速公路改扩建工程中，为了减少软土地基上新老路基的沉降差异和桥头跳车等病害的发生，通常采用复合地基进行软基处理。通过灰关联熵法分析了各因素对路基填筑期沉降的影响程度，对复合地基处理下软土路基沉降的敏感性进行分析。研究结果表明，各因素对复合地基处理下软土路基填筑期沉降的敏感性从大到小依次为：地表硬层厚度、路堤填筑高度、地表压缩模量、软土层压缩模量和路堤顶处理宽度、软土深度、填筑时间、软土层厚度。路基填筑期沉降是高速公路最终沉降量的重要组成，其影响因素很多，研究各因素对复合地基处理下软土路基沉降的敏感性，对于软基处理施工设计和施工期的监控有重要的指导意义。

Composite foundation is commonly adopted in soft foundation treatment to reduce the differential settlement between new and old subgrade and the bumping at bridge-head in expressway reconstruction and expansion. Through grey relation entropy method, the author analyzes the influence of various factors on settlement during subgrade filling and the sensitivities of soft soil subgrade settlement under composite foundation treatment.  Results show that the settlement during subgrade filling which accounts for the final settlement, is influenced successively by thickness of surface crust, height of embankment filling, surface compression modulus, soft soil layer compression modulus and the width on embankment top, depth of soft soil, filling time, and thickness of soft soil layer. This research is of guiding significance for the design of soft foundation treatment and the monitoring during construction.