The Characteristic Research Of Time-varying Viscous Grout In Porous Stratum

With big economic growth in China, major infrastructure construction projects have to deal with the stratum with abundant water. Because the loose geological structure and the high external water pressure, anti-seepage projects are often companied with great difficulty and high risks, which makes it the controlling part of projects. Once water gushing burst happened, serious casualties and huge economic losses will be caused, while the rescue is very hard, and the hidden security risks might be left for later operation. In addition, if the underground water kept draining for a long time, it will not only consume energy for pumping, but also incite geological and ecological disasters. For above reasons, the research on anti-seepage treatment in high pressure and rich water area is endowed theoretical and pragmatic significance.In this dissertation, the difficulties of anti-seepage treatment in high pressure and rich water area, as well as the characteristics of Nano-materials are taken into consideration for analyzing the viscous flow models of grout, the rheological properties of grout and its influence factors. Based on the analysis of the experiments concerning Nano-composite grout, rapid solidification Nano-composite grout, and the strength of consolidation, it concluded that the rheological properties of grout and the strength of consolidation changed with time and the percent of Nano materials.Stress field and seepage field coupling are analyzed in the process of grouting. It generated that the grouting pressure leads to porous skeleton changed, and the changes of porosity lead to the change of permeability, in this case, the coupling of stress field and seepage field should be considered during grouting. The principle of effective stress for porous medium is applied to analysis the fluid-structure coupling in the process of grouting, meanwhile, the coupling physical variables, dynamic models of porosity, permeability and viscosity are introduced. The diffusion radius thus can be defined by the foundational porosity and grout velocity. The single-hole sub-grouting verification is experimented for the diameter measurements and geotechnical tests on the on-site excavation stone. It shows that the calculation results are approaching more to the experiment results than to the traditional Maag formula. Therefore, the necessity of coupling consideration and the rationality of the application of fluid-structure coupling model to seepage field are verified.The construction program that combined the Nano-composite grout of controllable solidification and the grouting technology of filtering water is proposed, under the consideration about the geological conditions of high pressure and rich water area. The coupling mathematical model of grouting in porous medium is established, and the diffusion radius defined by the porosity and grout velocity is analyzed. The distribution of holes is designed according to the diffusion radius of grout in the sample coal mine engineering project in southwest China. Then, the permeability and the strength test were designed to verify grout effect. The final result shows that the permeability and the strength are greatly improved; the efficiency is also enhanced, while the energy consumption of grouting is reduced. This dissertation provides a new thinking for the anti-seepage treatment in high pressure and rich water area. It will be useful to prevent the gushing water disaster, to reduce the energy consumption, and to protect the under-ground water resources.