Mechanism Of Hydrodynamically Chemical Grouting In Porous Media

Based on fluids theory and underground water substance migration theory, this paper aims to study the different difussion patterns and conditions of grout under the static water, emprical formula of grouting pressure behaviour and porpous grouting effect. Furthermore, several methods including physical model experiment, numerical simulation and field test etc. are employed in this process. Besides, it is to analyze the gelation features of urea resin grout in motion and build the grout hydromechanical model under dynamic water. The research contents of this paper lies in the following aspects:1. The features of urea resin grout are analyzed on the basis of the research about anti-seepage adaptablity of the grout. The result shows that urea resin with a molar ration less than 1.5 is not suitable as the anti-seepage grouting material. The conditions of urea resin grout acting as the anti-seepage grouting material is also presented. On the basis of researching the gelation mechanism of the grout and labortary test result, it possesses the curing rules feature and water contamination feature of urea resin grout in the acid condition so as to provide the convincing reference for improving the groutability in the application of anti-seepage project.2. Based on the theory of similarity, the interior model test of grouting pressure in the grouting process is made. Having researching about the influencing factors of grouting pressure, the dynamic formula of chemical grouting is listed according to the similarity criterion. The formula shows that, according to the grouting pressure change, the groutability and its effects of gneis can be improved through adjusting grouting pumping capactity and grout gelation time and grouting pressure in the whole process of grouting.3. Based on the mechanical theory of cavity expansion model and unified strength criterion, the diffusion mechanics of the grout in soil mass is analyzed. And pressure conditions of the grout while penetrating and gadding in sandy soil is given and the rationality of this rule is verified through laboratory test.4. According to the migration rules of underground water, the grout flowing rules under porous conditions including diplopore, triporate and circle-type setting is studied and the distribution rules of grouting pressure and concentration diffussion features are analyzed by applying numercial analysis software VMODFlow4.0. The result proves that the pressure gradient rising in the grouting scope renders the rightabout flow of the grout. In other words, it is very difficult to form the continuous grouting induration between new grouting hole and old grouting hole. As a result, the grouting scope cannot be simlpe superposition of the haplopore grouting radial.5. The gelation time feature of the grout in stationary state is studied by referring to gelation time, the important parameter in the grouting process control. In the requirement of dynamic gelation features of grout, the testing platform of dynamic gelation is presented. By revolving speed instead of flow velocity, the viscosity changing rules of grout solidification at different revolving speeds are analyzed. Compared with the grout gelation time in static state, its dynamic state lies in certain hysteresis. According to the real-time viscosity change curve of gelresin grout in dynamic state, the mathematical formula of urea resin grout gelation is given. The formula indicates the rules of grout solidification viscosity as the time and shearing rate changes.6. Through laboratory test, the impact on the grouting effects under the conditions of different dynamic water is studied. On the basis of underground water migration model and numerical simulation software VMODFLOW, the rules about the interractions between the flow field of grout and that of dynamic water while grouting under dynamic water. By applying Eulerian equation of hrdromechanics, the grouting mechanical modle of chemical grout under dynamic water (urea resin grout) and the formula of grout changes over time and space and the optimal distance formula of the position of grouting holes are setup.