Study On Grout Diffusion Theory And Experiments Under Static Or Dynamic Loading

For solving the problems in the grouting fields, experimental study ,theoretical analysis and numerical simulation were used to study the grout diffusion of permeation, compaction and vibration grouting. Generally, the research work can be summarized as follows.1. Based on the generalized Darcy's law and theory for spherical and columnar diffusion model, the diffusion formulas of Bingham and exponential fluid injected into homogeneous sandy stratum was deduced and the algorithm for solving the formulas were proposed. By using the formulas the variation of necessary grouting pressure required the design along the depth of stratum can be calculated.2. The unconfined compressive strength and plastic strength of two kinds of hardening clay-based grout has been studied. It was analyzed how the main composition content affected the strength.3. The static grouting simulation test equipment was designed with such advantages as steady and controllable grouting pressure, convenient observation of the grout diffusion in the sand, possible simulation of static and dynamic water pressure. The grout diffusion was studied in the simulation experiment. And the permeability of saturated sand after grouting was compared with that before grouting.4. The vibration grouting simulation test equipment was designed. The grout diffusion rules have been discovered in the simulation test. And the mechanism of vibration grouting was analyzed.5. The static and axisymmetric Biot consolidation equation has been deduced. The supposed displacement principle and weighted residuals method were used to part the equilibrium equation and continuation. And The compaction grouting was simulated in saturated porous elastic material.6. With the elasto-plastic material model introduced into the equilibrium equation, the large displacement and strain Considered, and Jaumann stress and strain velocity tensor used, The compaction grouting in saturated porous elasto-plastic material was simulated.7. The pore pressure fluctuation of saturated sand from Xiangjiang River was studied in dynamic triaxial tests. Pore water pressure could not reach the confining pressure for nonisotonic consolidation or isotonic consolidation with high cofining pressure though the dynamic pressure was high or the vibration time is long enough. So a new formula was put forward to forecast pore pressure development in these conditions. From the point of view of energy, the relationship between pore water pressure development and stress-strain ring area was discussed. And from the point of view of strain path, the relationship between pore water pressure and strain path length was also discussed. And how the dynamic stress extent change had effect on the pore pressure fluctuation was studied.8. The change rule of stress-strain ring shape was studied as well as the relationship between axial dynamic strain and pore pressure.9. According to the axial strain failure standard, the relationship between the residual pore pressure and failure vibration time was discussed.10. How the dynamic pressure affects the grouting pressure cracking the soil was studied.11. The dynamic and axisymmetric Biot consolidation equation has been deduced. It was applied to analyze the reaction of saturated porous material under the action of burial dynamic pressure.12. With the dynamic elasto-plastic model of saturated sand introduced into the dynamic equilibrium equation, the large displacement and strain considered, and the business software combined, the dynamic grouting in saturated sand was simulated.The innovation points include:(1) Based on the generalized Darcy's law and theory for spherical and columnar diffusion model, the diffusion formulas of Bingham and exponential fluid were deduced for the first time.(2) The strength of two kinds of hardening clayed-based grout was compared with each other and the reason causing the difference was analyzed.(3) The static and dynamic grouting simulation equipments were designed for study on grout diffusion laws.(4) With the elasto-plastic material model introduced into the equilibrium equation, the large displacement and strain Considered, and Jaumann stress and strain velocity tensor used, The compaction grouting in saturated porous elasto-plastic material was simulated.(5) Based on a lot of dynamic triaxial experiments, A new formula was put forward to forecast pore water pressure development of saturated sand from Xiangjiang River.(6) How the dynamic pressure affected the grouting pressure cracking the soil was analyzed. During vibration, pore water pressure of saturated sand would increase. And it led up to decrease the cracking soil pressure, so the sand was easy to crack(when the grout viscosity is low).(7) With the elasto-plastic material model introduced, and the large strain considered, the business software second exploiture was done to simulate the dynamic compaction grouting.