Setting method of safe coal pillar for sand control in thick unconsolidated aquifer under hydraulic pressure

Abstract

The invention discloses a setting method of a thick loose water-bearing layer sand prevention safe coal and rock pillar under the water pressure effect. The method comprises the following steps of performing a liquid and plasticity limitation test on a clay layer positioned under a thick loose water-bearing layer covering a coal seam to be explored; performing a dry saturated water absorption rate test and a disintegration test on bed rock weathering zone rock positioned at the side surface of the water-bearing layer; determining whether the loose water-bearing layer is positioned in a sealed water pressure maintaining structure or not according to the liquid and plasticity indexes of the clay layer, the dry saturated water absorption rate of the bed rock weathering zone rock, and the disintegration performance parameter obtained in the tests; and if the loose water-bearing layer is positioned in the sealed water pressure maintaining structure, determining the thickness H<sp> of the sand prevention safe coal and rock pillar under the water pressure effect, and setting the sand prevention safe coal and rock pillar of the coal seam to be explored under the thick loose water-bearing layer under the water pressure effect according to the thickness. When the method provided by the invention is used for exploitation, the occurrence probability of coal mine sand inrush disaster accidents can be reduced. The method supplements and completes the theory of the coal mining sand prevention safe coal and rock pillar setting method under water bodies in China, and has high practical values.

Description

technical field [0001] The invention relates to the field of mining engineering, in particular to a method for setting a safe coal pillar for sand control in a thick loose aquifer under the action of water pressure. Background technique [0002] In recent years, due to the gradual depletion of coal resources, many mining areas in East China, North China and other places have taken the mining of shallow coal seams under thick loose aquifers as an important task in mines in order to increase the upper limit of mining, that is, the thickness of the loose layer is not less than 100m, and the aquifer is pristine. The water pressure is not less than 1MPa. Although my country has done a lot of research on mining under water bodies and accumulated rich practical experience, the differences in hydrogeological conditions in different regions, the water-rich degree of loose layers, and the degree of increasing the upper limit of mining have made my country's thick, loose water-bearing ...

AI Technical Summary

Problems solved by technology

With the development of thick unconsolidated bottom aquifer mining areas such as Juye in Shandong, Zhaogu in Henan, Huaibei in Anhui, and Datun in Jiangsu, according to the "Regulations for Coal Pillar Retention and Pressure Coal Mining in Buildings, Water Bodies, Railways, and Main Shafts" ( 2000 edition) weakly water-rich and water-bearing sand layers were left with sand-proof safety coal rock pillars, and sand-breaking accidents still occurred in coal mining faces in some mining areas, and such problems continued to increase, indicating that the retention methods in the regulations were not effective under unfavorable conditions. It has been unable to fully meet the requirements of depositing safe coal pillars for sand control in thick loose layers

Images