The Seepage Experiment Of Coal Under Vibration Environment

Coal mining in the process of excavation,due to the effect of mechanical vibration of the coal seam is continuous,inside the coal rock mass stress and strain,the original coal gas occurrence state of equilibrium is broken.Made with free with absorption occurs in change of coal gas in the body,as the vibration effect caused by the adsorption state in the process of mining occurrence in coal gas desorption,breaking the original occurrence of coal.To change the internal stress distribution of coal,changed the internal gas adsorption and desorption of coal influence the permeability of coal gas.At the same time,because our country is in a few large geological tectonic belt between the coal gas to low permeability gas,high ground stress,lead to the low degree of gas of coal seam gas exploitation,mine gas disasters.Therefore,research in the process of the excavation of coal under the action of mechanical vibration,the changing rule of the coal gas occurrence state of internal,is helpful for further understanding the gas permeability of coal,the perfect gas of coal seam gas mining theory and increase production of low permeability of coal bed methane gas in coal seam coal gas adsorption desorption migration rule and the exploitation of gas and coal mine safety have important practical significance.In this paper,by studying the vibration before and after the gas seepage in coal and desorption characteristics,has designed a kind of coal in the finite volume of low frequency vibration,change the internal state of the original structure of coal,thus to improve permeability of coal is vibration system.The system to a ES-05-150 electric vibration system as the core,the vibration test system,vibration platform and power amplifier;Combined with gas seepage triaxial test system of the gas seepage test on the condition of different vibration frequency coal seepage experiment was carried out.Based on the experimental research,coal of different vibration frequency as the variables,considering coal permeability characteristics of coal in different operating conditions.Under different confining pressure,different gas pressure,under the condition of different coal particle size,the different loading stages;the change rule of permeability of coal According to the experimental results to analyze the coal before and after the vibration and the characteristics of different particle size of coal permeability.For coal and gas outburst and the permeability in the process of mining of coal is provide theoretical basis for the research.Based on the experimental research,coal of different vibration frequency as the variables,considering coal permeability characteristics of coal in different operating conditions.Under different confining pressure,different gas pressure,under the condition of different coal particle size,the different stages of loading coal permeability change rule.According to the experimental results to analyze the coal before and after the vibration and the characteristics of different particle size of coal permeability changes.For coal and gas outburst and the permeability in the process of mining of coal is provide theoretical basis for the research.The experiment shows that coal sample after vibration,in the case of constant confining pressure,the permeability of coal sample first rapid decline in performance,with the increase of gas pressure in the gas pressure is 0.5MPa,the permeability decline rate,flat trend,coal sample permeability and gas pressure appear to oblique "V" change tendency;With the increase of confining pressure,permeability of coal is negative exponent form decreased;Under the condition of different gas pressure and confining pressure,with the increase of vibration frequency,permeability of coal is increasing trend in index;In 0HZ-40 HZ frequency when the coal permeability rate overall ascension is rising,in 40HZ-70 HZ frequency,speed of permeability of coal sample decreases,but compared with low frequency vibration of the coal sample permeability is ascension;Under the condition of different gas pressure,10-30 coal sample than 40 to 60 purpose the permeability of coal sample as a whole increased by 7% or so.Under the condition of different confining pressure,10-30 coal sample than 40 to 60 purpose the permeability of coal sample as a whole increased by 10% or so.