Base on the analysis of a real example of determination of dike top construction allowance for settlement for heightening a submerged dike on soft soil,this paper studied and discussed the method for determining the construction elevation in heightening of submerged dike.

With the technical development of the railway,the high stability of line and subgrade are required to support high running speed,hence accurately controlling and estimating the preformed settlement of the embankment are very important.

Taking the construction of Qingnian Avenue Station as example,the author presents such measures as the surface treatment of the utility pipelines,the control of the construction settlement and the advance ground consolidation that are taken during construction in order to protect the utility pipelines and to guarantee the construction safety.

Based on the site settlement information of soft soil highway section of Nan Rao Cheng highway of Yangzhou city, the settlement after construction of every stage is forecasted by the method of hyperbola.