Research On Permeation Grouting Experiment And Application In Sandy Strata

Permeation grouting is widely applied in grouting engineering, especially in the engineering with high requirement of ground settlement for its low grouting pressure and little disturbance to stratum.However, permeation grouting theory is lagging behind compared with engineering, and the theoretical formula now available can’t exactly guide the grouting engineering design and predict cost and effect of grouting because that grout permeating in stratum is affected by many factors. Aimed at the problems of permeation grouting theory and grouting engineering and based on others’ research,it is of important theory significance and engineering significance to carry out research on the grout diffusing theory, grouting effects and the qualitative and quantitative relations between grouting effects and the factors affecting grouting effects.Grout diffusing research is pivotal to permeation grouting theory research. Existing permeation grouting theory is based on which radiuses of the capillary in sandy strata are equal, moreover,Power-law non-Newtonian fluid and Bingham fluid are seldom studied. Based on which radiuses of the capillary in sandy strata are not equal, guided by permeating law of Darcy and grout diffusing theory of sphere and cylinder, the grout diffusing law of Power-law fluid grout and Bingham fluid grout are studied and the relationship between grouting pressure and grout diffusing radius is studied.Moreover, it is found that effective permeability coefficient decreases with grout spreading and effective viscosity coefficient varies with grout spreading depending on rheological parameter.The component, particle size and viscosity of THE Ⅱ sand consolidation agent are tested and the groutability of the grout material in gravel sand strata, coarse sand strata and medium sand strata of Shenyang strata,is studied. The specimens’ strength characteristics of grout material, sand consolidation agent, are tested and strength depend on time is studied.Permeation grouting experiment devices are independently manufactured with characteristics of controlling grouting pressure easily, simulating sandy strata grouted easily and detecting grouting effect easily. Using uniform design, the sand consolidation agent, as grouting material,spreading in Shenyang sandy strata is tested with these experiment devices. The quantitative relations between grouting factors(grouting pressure, strata parameters, grout ratio of water-cement) and grouting effects(grout spreading radius,gell strength, grout amount) are got with regression analysis and the influence degree of grouting factors on grouting effects are studied.The grouting engineering in wen-wu tunnel of Shenyang subway is designed according to experiment research result. The excavating stability of the tunnel reforced on pregrouting project designed to be numerically simulated with FLAC3D software is forecasted taking combined with the rule of gell strength depend on time.Moreover,it is reasonable to perform grouting design depended on research results by detecting the grouting effects of grouting engineering and analyzing of monitoring date of the tunneling progress, and it is feasible to forecast the stability of tunnel excavating with FLAC3D by comparing monitoring results with numerical simulation results.