Research On The Consolidation Settlement Of Soft Soil By Back Analysis

Abstract:Lianyungang marine soft clay is deposited by muck and mucky soil. It has the following characteristics:high moisture content,high void ratio,high compressibility,low permeability. Constructing expressway enmbankments in the natural ground,settling rate is comparatively great in the engineering period,and the stability of settlement hardly accomplish by the end of preloading period. It is necessary to predict post construction settlement of expressway embankment on this soft soil accurately in order to guarantee the safety constructing of road surface. This paper is concerned on the consolidation settlement of soft soil by back analysis,basing on the field observed data of Lian-Yan highway project in the part of Lianyungang.The main results of the sduty are obtained as follow:(1) Analysing the field observed data,find out some deformantion properties of Lianyungang marine soft clay.The results turn out that the relation between undrained shear settlement of Lianyungang marine soft clay(Su)and the maximum lateral displacement(Dmax)in ground is linearity,the same to the consolidation settlement(Sd).The ratio of Dmax/Su is 2～3,while Su/Sd is 0.01～0.08.(2) Designing the back analysis program of Biot consolidation FEM. The program adopted genetic algorithm as optimization method.Contrasting to the traditional methods, genetic algorithm has its merits: finding best value in the overall results; not very strict with the objective function.strong adjustability.(3) Researching on the consolidation settlement of Lianyungang marine soft clay by back analysis propgam.Take the part of natural foundation in Lian-Yan expressway as conmputing examples,the results turn out that the progam can obtain suitable conmputing parameters for the Lianyungang marine soft clay by the optimization method of genetic algorithm.It can predict the ground settlement in the loading stage.