Fast tunneling method for injecting high-temperature nitrogen through drilled holes in strata

Abstract

The invention discloses a fast tunneling method for injecting high-temperature nitrogen through drilled holes in strata. A mode of drilling the strata by groups and then injecting high-temperature nitrogen into the drilled holes in the strata step by step is adopted, and by means of the drilled holes in the strata of an extraction roadway at a low position, high-temperature nitrogen is repeatedlyinjected step by step; not only are coals among the drilled holes in the strata heated by the energy of high-temperature nitrogen to accelerate gas desorption, but also fracture permeability improvement of high-temperature nitrogen is achieved in different directions at different times. Increase, expansion and ventilation of cracks in the coals can be accelerated; additionally, cracking and ventilation improvement of the coals are facilitated under the coupling effect of temperature and pressure. By repeatedly injecting high-temperature nitrogen step by step, the problems of crack closure andreduction of gas density and flow during extraction are avoided, extraction of gas with high concentration and high flow by means of the drilled holes in the strata is ensured, the coals and the gas within a control range of a coal layer tunneling roadway are efficiently, safely and quickly extracted, and the speed of tunneling a single soft coal layer roadway with high emergent risks is increasedgreatly.

Description

technical field [0001] The invention relates to a method for rapid excavation, in particular to a method for rapid excavation by injecting high-temperature nitrogen into drilling through layers. Background technique [0002] Under the current regulations of coal mines, the excavation work in outburst mines should be done without digging outbursts or mining overhangs. Mining activities are strictly prohibited if comprehensive regional outburst prevention measures are not taken as required. In order to ensure the safety of a single low-permeability coal seam with a high risk of outburst under the mining condition of no protective layer during the roadway excavation process, many coal mines in the industry often choose no outburst risk in the range of 10-20m vertically below the coal seam excavation roadway. A low-level drainage roadway parallel to the excavation roadway is arranged in the rock formation. In the low-level drainage roadway, drill through-bed drilling holes to ...

AI Technical Summary

Problems solved by technology

However, due to the low gas permeability of the coal seam, there are problems in the subsequent gas drainage process after conventional drilling through the seam: the extraction range is small, the extraction time is long, and the extraction is difficult. Since the gas concentration in the roadway cannot be reduced in time, the coal seam The driving speed of the roadway in the working face is slow, which causes the imbalance of coal mine excavation and seriously affects the safety and efficiency of the coal mine

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