Causes and discussion of fault water inrush after regional treatment in coal seam floor

Abstract

Based on the water inrush from F28 fault of Ⅱ1028 working face in Taoyuan Coal Mine, the process of water inrush is described. The water inrush source and channel are analyzed according to the water level, water quality and water temperature. The failure depth and the height of confined water lift zone in fault zone are calculated by theoretical formula, the reasons of water inrush is illustrated, and the water inrush channel was blocked by grouting aggregate and cement through directional holes on the ground. The layout of regional control drilling hole, grouting method and material ratio were discussed. The results show that regional governance effectively blocked the water channel of Ordovician limestone and avoided the disastrous water inrush, the fly ash-cement slurry was not solidified in the fault zone, the effective grouting pressure of drilling through the collapse column and at the end of the fault was low, so the governance effect was poor, and the mining fault activation led to the water inrush. High strength cement slurry should be injected into the fault and broken zone disturbed by mining to improve the strength; the pressure loss rate along the grouting path decreases with hole depth. The grouting holes should not be too long. The pressure of “short circuit” in the middle of the diversion will decrease as a whole, and the length of the section without pressure in the hole increases with the amount of diversion. Pressure test should be carried out through the abnormal structure and roadway floor to avoid the phenomenon of “short circuit” of grouting.

Keywords

• floor water disaster
• fault water inrush
• ground directional hole
• grouting and plugging water
• aggregate pouring