| Zhejiang Province is located in the southern part of the Yangtze River Delta.Due to the influence of long-term geological history,a large number of soft clays are widely distributed in Zhejiang Province,which brings many complicatied problems to the construction and operation of transportation projects.The deformation of soft soil foundation is one of the most complicatied.Because of the obvious rheological property,the secondary consolidation deformation of soft clay is easy to occur under the load,which leads to excessive post-construction settlement and uneven settlement.Morever,it takes up a lot of time and money to repair the roads.Therefore,it is of great practical significance to study the secondary consolidation characteristics of soft clay and select suitable methods to predict deformation of soft clay in Zhejiang Province.In this paper,the physical properties and secondary consolidation characteristics of marine,lacustrine and alluvial soft clays in Zhejiang Province are systematically studied.The variation of settlement about Jiaxing and Shaoxing Highway Project in different periods is analyzed.Based on the parameters obtained from field investigation and laboratory tests,a numerical simulation model considering secondary consolidation deformation of soft clay is established by using Plaxis.What’s more,the advantages and disadvantages of theoretical formula method,numerical calculation method and curve fitting methods for predicting settlement are compared.The main work and conclusions are summarized as follows:(1)The composition and physical properties of soft clay in Zhejiang Province are summarized.The influence of consolidation pressure,compression index,plasticity index,liquid index,water content,overload preloading and overconsolidation ratio on the secondary consolidation coefficient of soft clay in Zhejiang Province is analyzed.The empirical formulas for calculating the secondary consolidation coefficient are obtained.(2)Based on Jiaxing and Shaoxing Highway Project,Hyperbolic method,Exponential curve method,Asaoka method and Poisson method are used to fit the measured settlement curves respectively.By comparing the fitting results and the measured data,the advantages and disadvantages of four curve fitting methods are summarized.(3)Based on Jiaxing and Shaoxing Highway Project,the effect of soft soil foundation treated by plastic drainage plate combined with surcharge preloading method is analyzed.The numerical simulation model considering the secondary consolidation deformation is established by PLAXIS to calculate the settlement of soft soil foundation in different periods.The reliability and applicability of the model are verified by comparing the calculated and measured results.On this basis,by comparing the results of Theoretical formula method,Curve fitting methods and Numerical calculation method the effect of three kinds of settlement prediction methods is analyzed. |
