Time-depended Back-analysis And Prediction Of Post-construction Settlement For Embankment In Soft Clay

Many highway construction have to be built on thick soft clay foundation. The soft foundation has large settlement, and the post-construction settlement will last for a long time. The post-construction settlement do great harm to the traffic, and the request for deformation control is very strict especially for the highway. Therefor it is necessary to calculate or forecast the settlement of soft clay foundation. Because the number of influence factor is large and they are changing perpetually, what's more the soft clay character is very complex, It's very difficult to calculate or prediction the foundation post-construction settlement accuratelly. Control of post-construction settlement is the main problem for highway construction, which directlly effects the cost of the project, and relate to the maintenance as well as the safety of the project. So research the prediction method of the foundation post-construction settlement is necessary.Considering all kinds of calculate method of the post-construction settlement of soft clay foundation, adopted time-depended Merchant's model, From the observation date obtained during construction, the geological parameters may reasonably be determined by direct optimal method, then we can predict the after settlement.In this paper, Firstly, two-dimensional formulas of Biot's consolidation FEM base on elastic model and Merchant's model are presented to calculate settlement of saturated soft clay ground. From the observation date obtained during construction, the geological parameters may reasonably be determined by time-interval back-analysis. Then analyse the geological parameters' change trend and discuss the feasibility of time-depended back anslysis. Then compiled FEM considered the geological parameters' change by the time. The back analysis was performed for two highways based on the program and the results tested. Furthermore,this paper dicussed the weight coefficient of aim function and the geological parameters' interaction.Based on characteristic of the highway consruction and the dynamic design method, considered the time-changing geological parameters, the time-interval back-analysis and time-depended back-analysis is presented in this paper. The actual detection data show that these method is effective and practical, which can improve back-analysis precision, shorten the precast time and can make reference to the design, construction and maintenance of soft clay foundation.