Micro-Experimental Studies And Theoretical Analysis On Permeability Of Micro-Fine Cement

With the depletion of the shallow coal resources, it is imperative to build deep shaft. The depth of the shaft increases, so the strata pressure and hydrostatic pressure is also growing. The micro-fracture seepage effect of shaft concrete wall increases rapidly in the high pressure, leading the water inflow of shaft exceeding standard. Grouting is one of the most effective methods to prevent water leakage in shaft wall. However, the current grouting material and technology can not achieve the desired results for various reasons. In future, micro-fine cement will become the ideal grouting material with its high durability, low cost, non-pollution and other characteristics. Therefore, this paper carries out experimental studies on micro-fine cement in the following four aspects:Firstly, carrying out experimental study on rheological properties of micro-fine cement slurry based on the physical and mechanical properties. The influence law of water cement ratio and water reducing agent on the viscosity of micro-fine cement slurry is reached. The time variation characteristic of viscosity and the influence of water reducing agent on it are also worded out in this thesis.Secondly, the model of rock micro-fracture is designed according to the similarity theory. Different diameter stainless steel filter is adopted to simulating the micro-fracture which has corresponding opening, and experimental studies on the groutability of micro-fine cement slurry is carried on using model. Then, the results of the model test are applied to rock micro-fractures.Thirdly, the micro-features of the micro-fine cement stone are observed using scanning electron microscope. From the microscopic point of view, the influences of water cement ratio and high efficiency water reducing agent on cementation state of the micro-fine cement stone are researched.Fourthly, proceed from the geometrical parameter of single rock fracture and the flow pattern of micro-fine cement slurry, theoretical studies about the flow rule of micro-fine cement slurry are carried out, obtaining the flow equation of the slurry in two-dimensional smooth micro-fractures.