Research Of Soft Soil Consolidation-creep Model Parameters Identification Based On LSMPS Algorithm

In the process of soft soil subgrade under external loads, the first is the consolidation deformation produced by pore water discharge, as the soil skeleton was tight, under the action of load will produce deformation related to time-creep. How do you determine the soft soil roadbed settlement amount and Discusses the soft soil consolidation-creep mechanism has become an important research direction in soft soil reinforcement and stability. Based on soil mechanics theory, the classical consolidation theory, the creep model of porous media theory as the foundation, through conducting soft soil obtained from Panjin coastal highway roadbed triaxial shear test for the soft soil consolidation creep data such as the vertical settlement and pore water pressure and the generalized Kelvin consolidation creep model is put forward, based on the algorithm of least square method based on pattern search-LSMPS to simplify the parameter searching and optimization of the generalized Kelvin model, and based on the engineering simulation, soft soil roadbed consolidation-creep mechanism engineering simulation is analyzed. The specific research results are as follows:(1) in the soft soil under different confining pressure triaxial compression creep test, the classification of soft soil specimen under load under different deviatoric stress level of pore water pressure and time relationship, and the development of vertical deformation with time curve, Chen loading method is used to change the rating load curve into "loaded" respectively, using the same time stress strain relations will "each loading curve into stress-strain curve etc. Through the study found that the attenuation of the exponential type function can describe the creep of soft soil consolidation and the function relation between the time, compared to the generalized Kelvin creep model and the attenuation of the exponential function between highly similar characteristics, generalized Kelvin model can therefore be used to describe the consolidation creep characteristic of soft soil specimen.(2) using the LSMPS method to simplify the parameters of the generalized Kelvin model search mode, the parameters of the model through iterative search and optimization method, the study found that the generalized Kelvin model simplified constitutive equation is a monotonic function of each model parameters can be determined in theory, the constitutive equation only exists in the global extremum without typecasting search into a local optimum. The generalized Kelvin model is compared by LSMPS constitutive equation and experimental data, the similarity between the correlation coefficients of above 0.97, so using this method to determine the constitutive equation by fitting the soft soil consolidation creep function effect is better.(3) Soft soil Biot consolidation equation is analyzed, considering the node additional stress on the influence of Biot consolidation equation when the creep of soft soil happen, determine the finite element model of the soft soil consolidation-creep unity interaction; using ADINA8.4 provide powerful engineering model parameters of the simulation platform will be determined by LSMPS into Lubby2 parameters in the simulation of ground stress of soft soil subgrade, consolidation and creep deformation in soft soil subgrade internal distribution?The above research results to further enrich and improve the soft soil consolidation-creep deformation characteristics, the effective control of vertical settlement of soft soil subgrade, and the reasonable design of soft soil roadbed engineering construction plan provides the basis.