Stability Analysis Of Hydraulic Support In Fully Mechanized Mining Face With Large Dip Angle Coal Seam And Study On Safe Fault Crossing Technique

The reserves of high-inclined coal seams in China are very rich,so it is of great significance to study the safety mining of high-inclined coal seams.This paper is based on the geological conditions of the 10#coal seam mining in Taoyuan Coal Mine,and takes the safe and efficient mining of the?1042 large dip face as the research object.It comprehensively adopts laboratory testing,theoretical analysis and calculation,numerical simulation,and on-site industrial tests.In-depth research was carried out on the stability of hydraulic support at large inclination face and the technical measures for safety crossing fault.The main research results in the paper are as follows:?1?The geological and hydrological conditions of 10#coal seam in Taoyuan Coal Mine are relatively complex.On this basis,a complete coal rock sample of?1042 large-inclination working face was collected,and the physical and mechanical parameters of coal rock were tested in the laboratory to obtain the coal seam and the roof and floor Physical and mechanical parameters such as compressive strength,tensile strength and shear strength of rock layers.?2?Based on the mining geological conditions of the 10#coal seam?1042 large-inclined face,considering the need for safe mining of large-inclined coal seams,it is determined that the roof beam structure of the face support is an integral rigid roof beam with telescopic beams,and the base structure is beneficial to reduce The overall rigid base of the small base plate.Through theoretical calculation and numerical simulation,it is determined that the support strength of the hydraulic support is 0.74 MPa,the working resistance is 8000 kN,the initial support force is 6640 kN,and the support height is 2.1⁴.7 m.In order to ensure the stability of the hydraulic support on the working face,the ZZ8400/21/48 type support shield hydraulic support is used in the middle of the working face,and the ZQL10800/21/48 hydraulic support is used on the end.?3?Based on the mining technical conditions of?1042 high-inclination working face in Taoyuan Coal Mine,this paper briefly analyzes the stress characteristics of the support at high-inclination working face.On this basis,the support dumping mechanical model and the sliding mechanical model were established on the working face tendency and trend respectively,and the stability of the support in the normal mining period and the special mining period?during fault crossing?of the large inclined working face was analyzed.The analysis results show that the factors that affect the stability of the working face support mainly include the technical parameters of the support itself and the mining geological conditions of the working face.By increasing the friction factor between the bracket and the top plate,the"three-machine"joint stability control technology,installing anti-falling devices on the top beam of the bracket,and changing the way of moving the face,it greatly improves the stability of the face support.?4?Based on the development profile of the F₄ fault,the over-fault scheme for cutting the roof and leaving the bottom coal was determined.Using theoretical calculations,it was determined that the slope was raised at a slope angle of 7°at a distance of about 24 m from the fault plane,and the mining height when crossing the fault was 3.0 m.During the fault crossing,Ma Lisan was selected as the grouting material to strengthen the broken coal rock near the F₄ fault zone.The range of grouting was determined to be 20 m before the fault and 15 m after the fault,and various grouting parameters were determined to improve the stability of the broken coal rock mass.During the fault crossing,a combination of mechanical rock breaking and blast rock breaking is used to quickly cross the fault and determine the parameters of the blasting process.The program basically achieved the purpose of safely crossing the fault.?5?Through calculation,it can be seen that the critical tipping support resistance of the support during the II1042 high-inclination face during fault crossing is 6980.81kN,and the critical sliding support resistance is 5979.21 kN.It is reasonable to choose ZZ8400/21/45 type bracket?rated working resistance is 8400 kN?for the working surface.The paper has 45 figures,10 tables,and 98 references.