Study On Treatment Of Hard Roof By Static Crushing Method In High Gassy Mine

In order to solve the problem of increasing the suspended distance of the hard roof in the goaf of the fully mechanized mining face in the high gas mine,the artificial blasting roofing method is usually used in the actual project to deal with the caving problem of the roof of the goaf in the mine.This paper discusses two main methods for dealing with the suspended roof problem: gunpowder blasting and hydraulic fracturing.Comparing the advantages and disadvantages of these two methods and the applicable conditions,it is concluded that gunpowder blasting and hydraulic fracturing are not suitable for high gas mine treatment.The conclusion of the ceiling.This paper introduces the concept of “static crushing technology” to treat the suspended ceiling at the end of the working face of high gas mine,and realizes the process of safe,efficient and environmentally friendly falling of the roof of the curved triangle.The forming conditions of arc triangle area at the end of mining roadway and its influence on surrounding coal pillars are analyzed by means of theoretical analysis and experimental research.Taking limestone as an example,this paper takes theoretical analysis and true triaxial physical simulation experiment as a method to study the fracture initiation and propagation law of limestone without prefabricated cracks and pre-cracks with different widths during static fracture.The main research contents and results are as follows:(1)Master the chemical reaction process and mechanism of static breaker,understand,study and master the rock breaking mechanism of static breaker.(2)By comparing the static fracture effect of limestone sample with or without prefabricated cracks,the rule of the influence of prefabricated cracks on the initiation and expansion of limestone is studied.(3)By comparing the effects of different prefabricated crack widths of limestone specimens after static fracture reaction,the influence of prefabricated crack widths on the initiation and propagation of limestone is studied.The results of this paper provide a reliable theoretical basis for the problem of handling the suspended roof of the upper roof of the mining roadway in the high gas mine and the caving of the hard roof in the goaf,and it has important promotion value.