ABSTRACT Based on a harbor construction project in Shanghai, the Mesri creep model was introduced to depict the creep deformation behavior of layered soft ground. The parameters of Mesri creep model were determined by means of back analysis method through using field monitoring data of ground settlement. The objective function was established by the least square method, and the variables for the function were optimized. Taking account of the property of layered soil deposits, layered iterative back analysis method of parameters was carried out. The comparison between the calculated ground settlement and that of measurement confirms the reliability of this new back analysis method. At last, the long-term ground settlement after construction was predicted on the basis of the results of back analysis.
INTRODUCTION The layered soft clay ground was widely distributed in the southeast coastal area in China. Because of the non-negligible creep deformation, the total settlement of soft clay ground should consider the coupled effect of primary consolidation and secondary consolidation (Karim et al, 2010). Through analyzing the observed settlement of the Dapu road tunnel in Shanghai, Zhan et al (1993) have found that the settlement induced by secondary consolidation was about 12 percent of the total settlement in that construction field. Refer to the calculation of creep deformation, the theory method by use of various rheological models was widely applied. In general, the parameters of rheological models were achieved from the laboratory tests. The big problem of this method was that the in-situ stress condition cannot be well reproduced in the lab tests. The disturbance of sampling will also influence the precise of the parameters of models. Therefore the back analysis method based on the field observed data was more and more popularly used in the prediction of ground settlement.