The Constitutive Model Of Xingheng High Way Soft Soil Considered Microstructure

The rapid development of China in recent years, large buildings including underground and above ground building after another, most of these buildings located in littoral or widely distributed over the lake with soft soil, soft soil engineering problems have cropped up more and more attention.The soft soil with micro-structural properties,makes a big difference in the calculation of the presence of soft soil deformation and destruction of some calculation results of the traditional theory of constitutive model and the actual situation. It also makes the soft soil constitutive model considered microstructure research become a key issue for the soft soil characteristics of the study.Thesis Xing Heng high way soft soil to start research for the study.The main content and achieve results carried out as follows:By Xing Heng high way soft soil undisturbed soil subgrade soil test indoor and scanning electron microscope test, the basic physical and mechanical properties and SEM images.Then come Xing Heng high way soft soil roadbed undisturbed soil pore pore size distribution, pore microstructure quantitative parameters, particle microstructure quantitative parameters,and soil samples in different vertical and horizontal consolidation pressure under the above SEM images of the microstructure of the picture that makes a quantitative comparative analysis,reveals the variation of soil deformation process of the turkey particles and pores, thus describes the soil macroscopic deformation occurs at the microscopic laws.Using particle flow code PFC standard consolidation tests and conventional triaxial tests simulated,stress-strain curves obtained.By numerical simulation results with the measured test results comparison found PFC built-in contact constitutive model can reflect the actual soil constitutive relations to some extent,establish the constitutive model which considering soft soil micro-structure.Assuming the mechanical properties of soft contact surface of soil particles obey the elastic-plastic Mohr-Coulomb criterion to criterion-based,elastic part determined by Hertz-Mindlin elastic, plastic part by introducing a cone yield surface reflect its characteristics.by "optimizing hypothesis approach" to achieve transform from displacement of the contact surface of microscopic particles to macroscopic strain.Then achieved through energy conservation methods to force conversion of the contact surface microstructure macroscopic stress,and standard of consolidation tests and conventional triaxial test data for constitutive model is validated.The resulting model can reflect the macroscopic stress-strain relationship unearthed bodies from the microscopic point of view.results of model predictions with experimental results are consistent.