滨海高速公路因软土欠固、海盐侵蚀和鱼塘开挖等因素导致路基出现一定程度的差异沉降，对高速运行车辆造成严重的安全隐患。为了探讨软土路基沉降变形规律，对路面沉降量、水平侧向位移和路基裂缝间的关系进行分析。基于路面实测沉降资料，建立以误差平方和倒数与误差绝对值倒数为基础的变权重组合预测模型。工程实例分析表明，当路面累积沉降差大于等于60mm和水平累积侧向位移大于等于30mm时，软土路基路面会出现反射裂缝。此外，利用统计学原理合理分配4种拟合优度较大的成长曲线模型的预测误差而建立的变权重组合预测模型比单项预测模型的鲁棒性强，吻合效果好，且满足实际工程要求，可为滨海高速公路软土路基工后沉降预测提供一种实用而有效的方法。

Coastal expressways usually show a certain degree of differential settlement resulted from under-consolidated soft soil, eroding sea salt and excavated fish pond and other factors, which has caused serious safety hazards to high-speed vehicles. To explore the deformation law in soft soil subgrade, the relationship among the surface settlement, horizontal lateral displacement and subgrade cracks was analyzed. Based on the measured settlement data, two variable-weight combination forecasting models on the basis of the reciprocal value in square sum and absolute value of error were established. The engineering examples shows that when the cumulative surface settlement difference was larger than or equal to 60mm and the horizontal cumulative displacement was larger than or equal to 30mm, respectively, the reflective cracks are likely to appear on the soft soil subgrade. Moreover, the variable-weight combination forecasting model by using statistical principles to reasonably allocate the forecast errors from the four growth curve models has better fitting effect and robustness than the single forecasting model. And it can meet the actual engineering requirements and provide a practical and effective method for the post-construction settlement prediction in the soft soil subgrade of coastal expressway.