Study Of The Mechanism Of Controlling The Overlying Rock By Injecting Ash Thick Liquid Into The Mining Collapse Zone And Of The Calculation Of Surface Mining Subsidence Deformation

It can cause the space in rock underground when the underground coal exploited. The mining space move in overlying rock to surface, and the surface subsidence must be caused by underground coal mining unless we deal with the mining space very good. The surface subsidence not only destroys the ecological environment, but also damages the surface of buildings.Based on the studying of the current situation of controlling the overlying rock mining movement and the surface subsidence, one technical approach is advanced about"Fly ash is injected into caving zone by high pressure controlling roof and overburden movement", and achieves the purpose of controlling roof and deformation of overburden movement, slowing surface subsidence, assuring the security of buildings or structures. This paper is mainly about the following major studies.Using numerical simulation and physical simulation method shows the characteristic of mining collapse zone in different mining depth, different mining width and under the different overlying strata types conditions ; gives the flow rule of present flowable fly ash body at collapse strap fragmented rock body and the subsidence characteristic of old rock and strata before and after grouting.Based on the rock plate theory, through the theoretical analysis of the roof structure of overburden rock types, and deduced the mathematical model of roof is derived in thick and thin or thick hard rock plate (laminated) rock plate deformation at the top of it, and gives the calculation method of maximum subsidence of the cover rocks at the top of the coal seam .Using numerical simulation analysis, the width of the strip mining all dancing with mining falling charge injection control surface overlying strata and the process of the simulation, gained the process of mining of overburden rock and surface subsidence of the change, and evaluated the results of grouting effect.Charged with the collapse of the different particle size rock proceeding uniaxial compaction tests witch is restraint on both sides and got all kind of rock deformation, porosity, and broken expansion coefficient and the axial stress changing relations between it, and analysis the changes of these parameters on impact of the grouting.After the mining collapse zone broken rock fly ash slurry grouting, a special material is generated. In this paper, this material is defined as"mixed rock", and precede stress-strain test on such special material, and established the constitutive equation of it. Using the test, it can gain the relation of "rock - pulp complex" deformation and load pressure, in different pressure and in different circumstances. The changes in the degree of compaction of different water-cement ratio and the strain characteristics of it, and gives the deformation calculation method in the whole mixed rock in support of the overlying strata.Papers finally gives the technology works example, provides the technical implementation of the proposed design ideas and the methods to assure the relevant parameters.