Principle And Application Of Intergrated Control Of Roof Cutting With Hydraulic Fracturing And Cable Injection For The Gob-Side Entry Retaining Under Intensively Dynamic Pressure

As one of the mining techniques with pillarless coal,gob-side entry retaining technology has the advantages of high coal recovery rate,relieving the displacement pressure of mining,solving the problem of gas accumulation in the upper corner and so on.It is the focus of coal mining layout research.Compared with the traditional gob-side entry retaining,the surrounding rock deformation of gob-side entry retaining under intensively dynamic pressure by the mining of 3-4 working faces is more severe,and the corresponding difficulty in control is also greater.How to solve the difficulty of gob-side entry retaining under the influence of such intensively dynamic pressure is particularly critical.In view of the surrounding rock deformation characteristics of gob-side entry retaining under intensively dynamic pressure,this thesis takes typical gob-side entry retaining under intensively dynamic pressure in Zhongxing Coal Mine as the research object.This thesis adopts the methods of field investigation,theoretical analysis,numerical simulation,mechanical calculation and field test.The principle of intergrated control of roof cutting with hydraulic fracturing and cable injection for the gob-side entry retaining under intensively dynamic pressure was studied,and the application effect of this technology was analyzed.Finally,it has been applied in the field.The main research results were as follows:(1)The deformation of surrounding rock of gob-side entry retaining in 1209haulage roadway,3201 haulage roadway and 3203 haulage roadway in Zhongxing Coal Mine was investigated respectively,and the surrounding rock deformation characteristics of gob-side entry retaining under intensively dynamic pressure was summarized.(2)Three groups of mechanical calculation models were established respectively,including the roof cutting with hydraulic fracturing model of gob-side entry retaining,the grouting anchor cable supporting model of gob-side entry retaining,and the hydraulic fracturing with the grouting anchor cable control model of gob-side entry retaining,the control mechanism of intergrated control of roof cutting with hydraulic fracturing and cable injection on the surrounding rock stability of gob-side entry retaining was revealed.(3)The mining model of gob-side entry retaining under intensively dynamic pressure was established by FLAC^3Dsoftware.The stress evolution characteristics of surrounding rock in the sequential mining process of adjacent and overlying working faces of 3203 haulage roadway under the condition of original support and hydraulic fracturing and roof cutting were simulated and analyzed respectively.(4)The surrounding rock displacement analysis model of gob-side entry retaining under the influence of intensively dynamic pressure is established,and the surrounding rock displacement variation characteristics of the original support scheme,single hydraulic fracturing roof cutting pressure relief scheme and roof cutting bolt grouting integrated control scheme are simulated and analyzed.(5)The field practice of typiacl gob-side entry retaining under the influence of intensively dynamic pressure--in 1209 and 3203 haulage roadway gob-side entry retaining of Zhongxing Coal Mine is carried out by using integration technology of roof cutting and anchor injection.It verifies the good control effect of integration technology of roof cutting and anchor injection in the surrounding rock of gob-side entry retaining under the influence of intensively dynamic pressure.There are 67 figures,3 tables and 77 references in this thesis...