The Study Of Water Inrush Mechanism On Seepage And Stress Coupling Damage Of Coal Floor Under Water Pressure

In resent years, with the increase of mining depth in the Dongjiahe coal mine, the mining environmentis becoming more complex, the ground stress and water pressure are increasing constantly, the coal miningunder the threat of ordovician limestone water has been outstanding in the lower Taiyuan Formation, it isvery imminent and important how to efficiently prevent and control water disaster problem of ordovicianlimestone karst. This thesis centres on the influenced factors that affected floor water irruption,establishment of mathematical mechanical model coupling seepage field, establishment of fluid-solidcoupling numerical model, the distribution of mine karst water inrush danger zone from floor and designconsideration of floor gronting reforming engineering. Through comprehensive use of theoretical analysis,numerical simulation, in-situ test and laboratory testing, a systematic research were carried out about theinfluence of seepage and stress coupling on mining failure features and water inrush mechanism of seamfloor, and the main work is as follow:(1) On the base of engineering geological and hydrogeological and the previous inrush data ofDongjiahe coal mine, the influenced factors that affected floor water irruption has been studiedsystematically in No.5coal of Dongjiahe coal mine, including head pressure and the water abundance ofOrdovician limestone, floor aquifuge lithologic, rock assemblage characteristics, geological structure andground pressure and so on. The reasons for floor water invasion of No.5coal of Dongjiahe coal mine isfounded on the interactive effect of these factors, Including dominant factors which includes geologicalstructure and head pressure, the subjective factors which includes the water abundance and rockassemblage characteristics, the promotion factors which includes ground pressure, the subjective factorswhich includes the inclined length and mining area of the coal face.(2) By using the method of theoretical analysis, the paper is the mutual combination oftheoretical study and site measurement, based on field test research of mining distortion and failurecharacter of coal seam floor, the evolutional regularity of mining destruction and the maximal failure depthfor No.5coal of Dongjiahe coal mine have been basically grasped, the key technological problems of fieldmeasurement is realized by theoretical method. (3) By using of the software of the coupling system of flow and solid in rock failure processanslysis(F-RFPA2D), the bottom board structure for No.5coal of Dongjiahe coal mine is established basedon coupling of seepage field and stress field, the numerical simulation was conducted for the influence ofmining and seepage, the change law of mining failure features and percolation characteristics of seam flooraquifuge and is revealed, which provides the scientific basis that will be helpful to the further study forfloor faultage’s water regularity mining on the top of water pressured.(4) Through the systematic researching from the article, and applying researches all above to thegrouting reinforcement project of floor aquifer in No.22507working face of No.5coal in Dongjiahe coalmine, the fluid-solid coupling numerical analysis method is used for water disaster control practice, andgrouting reinforcement strengthening and rebuilding technical method based on simulated output was putforward, safety mining of No.22507coal mining face has been realized at present, which have achievedenormous economic benefits and social benefits. These research results have provided the referenceexperience that will be helpful to the further prediction and prevention for floor water disaster of ordoviciankarst mining on the top of water pressured in Dongjiahe coal mine and even all over Chen-he coal minearea.