Deformation And Stability Evolution Of Embankment Over Sloped Weak Ground By Particle Flow Code

In the southwest region of China, sloped weak ground is widely distributed. Safety problems such as excessive deformation and instability of engineering will happen because of its unique cross section geometric features and slope soft soil properties. The existing research of the sloped weak ground under embankment load have ignored a characteristic that he rock mass medium has strong discontinuity, carried out the analysis through the theory of continuum mechanics, and did not pay fine description on the whole process of deformation and stability evolution. Set the embankment over sloped weak ground as the research object, based on particle flow method, depended on the research of the indoor geotechnical centrifuge model test, fully considered the discreteness of rock and soil medium, Studied the whole process of the vertical settlement and lateral deformation of the embankment over sloped weak ground after the foundation of embankment, analyzed the dynamic evolution law of stability of the embankment over sloped weak ground, and provided necessary theoretical support for design and reinforcement technique of the embankment over sloped weak ground from the perspective of mesoscopic mechanics.Thesis mainly carried out the following work:(1) On the basis of brief introduction about the indoor geotechnical centrifuge model test, elaborated the calibration process between macroscopic and mesoscopic parameters about soil based on the biaxial test, and discussed a number of key link about the particle flow code model in the process of building. Checked the reliability the embankment over sloped weak ground model by particle flow code through compared with centrifugal model and numerical model from the macroscopic deformation shape and surface layer displacement field distribution. Thus laid a good foundation for subsequent analysis of the embankment over sloped weak ground by particle flow code.(2) Based on particle flow method, solved the mathematical physical model of the embankment over levels and sloped weak ground, studied the whole process of deformation evolution about level and sloped weak ground under embankment load. Analyzed changing law of foundation deformation coefficient, coordinates of measuring points, porosity and stress at any step during the process about deformation evolution, explained the differences of deformation evolution process and the mechanism of the embankment over level and sloped weak ground.(3) Introduced the basic principle of particle flow strength subtraction, instability criterion, Analyzed the particle flow strength subtraction of the embankment over sloped weak ground. Discussed the changing law of foundation deformation coefficient, coordinates of measuring points, porosity and stress at any step during the process of dynamic evolution of the embankment over level and sloped weak ground when they got the critical strength degradation state. Compared the differences of the results of particle flow code strength reduction and other calculation methods, such as finite element shear strength subtraction, finite difference subtraction shear strength and rigid body limit equilibrium method.