| Grouting is widely applied to reinforce working face and roadways, plugging water of roof in mine, preventing leakage and reinforcing surrounding rock of dam foundation, rising and correcting building and so on. At the same time, grouting technology is greatly developed by multifarious new grouting materials, new technology and new equipment. By contraries, study on grouting theory develops slowly. The main reason is that grouting is a complicated and systematical technology and affected by many factors which are material character, joint character, grouting technics, climate, design environment and so on.In this paper, development of grouting, grouting material and classification of grouting are discussed. Basic theories associated with permeability of grouting are analyzed and summarized in detail. Some new perspectives about rheology of material, relation effecting grouted medium, grouting stress, etc are introduced. Preliminary study has been done. Some results are discussed as follows:1.New polyurethane grouting material with effects of waterproofing and rockmass reinforcing has been developed. This material avoids scale unmatching caused by abrasion of sealed components and congestion of pipelines, and can effectively reinforce and close over availably cracked coal and rockmass on condition that large-scale pours water in mine.2.New urea-formaldehyde resin grouting material has been developed which has low-lying viscosity and virulence and strong penetrability. The viscosity of the material is 60Cp～30Cp when condition temperature is 15℃～25℃, solidified speed may be adjusted accordingly as solidified dose and the uniaxial compressional intensity can exceed 5MPa. Roof falling due to dislocation of weak incompact coal and rockmass can be solved rockmass through grouting the material. The potential safety problems are removed and the mine can be normally extracted and drilled.3.A three-dimensional, stress invariable penetrating experimentation and device has been independently designed. An inverse proportional relation between penetrative coefficient and surrounding stress and viscosity of the material was obtained through the test.4.Formation and distribution of flaw of affecting seepage flow are detailedly analyzed depart from distribution of flaw in rockmass, character of seepage flow and mechanism of chemical grouting.5.Newton liquid grouting diffusing model is established and grouting diffusing theory is developed based on time-variance of serum's viscosity as well as other factors such as obliquity and azimuth of crack and underground water stress. The outstretched radius of serum increases constantly along with grouting time, and the increase ratio of the outstretched radius of serum is faster in early period than in late period.It is concluded that stress grads of frontal surface gradually and stress in cranny channels reduce, and velocity of serum flow and flux of serum gradually decrease. There is a extremum in grouting outstretched radius. 6.The radius of serous diffusion is bigger according to initial viscosity of fluid , mechanic width of flaw and pressure of grouting, because breed of flaw and grouting craft affect the radius of serous diffusion.7.It is proved through case studies that the grouting outstretched theory reflects serous fluid outstretched rules and the results are consistent with the practical application. Based on comprehensive study and comparatively analyzing on the hypothesis and presupposition involved, the qualitative rule and quantitative conclusion are achieved. The necessary geological parameters and serosity capability can be measured through the grouting outstretched model. The model discussed in this paper has some practical values.
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