Patent AU-2020100227-A4 (AU)
Title: Method for determining coal wall rib spalling of large mining-height fully-mechanized mining face of shallow coal seam
Inventor: HUANG QINGXIANG
IPC: E21F15/00
Filed: 2020-02-16
Granted: 2020-03-26
Abstract: The present invention discloses a method for determining coal wall rib spalling of a large mining-height fully-mechanized mining face of shallow coal seam. The method includes: establishing a "support-coal wall-roof' structure model of a large mining-height fully-mechanized mining face of shallow coal seam; establishing a mechanical model of periodic fracture of a main-roof key stratum, and determining a determining condition for tensile fracture of a voussoir beam of the main-roof key stratum; when tensile fracture of the main-roof key stratum occurs in advance, establishing a mechanical model of an elastic foundation beam of an equivalent immediate roof, and determining a discriminant for tensile fracture of an equivalent immediate roof stratum; and when tensile fracture of the equivalent immediate roof occurs in advance, determining a condition for coal wall rib spalling of the large mining-height working face of the shallow coal seam. Coal wall rib spalling of the large mining-height working face of the shallow coal seam is organically combined with roof movement and support control to comprehensively and accurately reflect a stress state of a coal wall, reveal the mechanism of coal wall rib spalling of the large mining-height working face of the shallow coal seam, and determine a determining condition of coal wall rib spalling, so as to provide a scientific basis for controlling stability of the coal wall and conducting safe mining. Establish a structui model "support-coal wall-roof' of a large mining-height fully-mechanized S1 mining face of shallow coal seam based on step voussior beam structures of an equivalent immediate roofand amain-roofkey stratum of the largemining-height working face of the shallow coal seam Establish, according to the structure model "support-coal wall-roof'of the large mining-height fully mechanized mining face of the shallow coal seam, a mechanical model of periodic fmcture ofthe S2 main-roofkey stratum bas ed on a phase in which aroof key stratum of the large mining-height working face of the shallow coal seam is periodically fractured Determine adetenmining condition for tensile fracture of a voussior beam of the main-roofkey stratum based on formula (1) according to the mechanical model of periodic fracture ofthe main-roof S3 key stratum When tensile fmctur of themain-roofkey stratum occurs in advance, establish, according to the determiningconditionfortensilefacturofthevoussiorbeamofthemain-roofkeystratumandthe structum model "support-coal wall-roof'of the large mining-height fully-mechanized mining face of S4 the shallow coal seam, a mechanical model of an elastic foundation beam ofthe equivalent immediate roof based on the phase in which the roofkey stratum of the large mining-height working face of the shallow coal seam is eriodically fractured Determine adiscriminant for tensile fracture of an equivalent immediate-roof stmtum based on S5 formula (2) according to the mechanical model of the elastic foundation beam ofthe equivalent immediate roof When tensile fmctur of the equivalent immediateroof occurs in advance, determine a condition for S6 coal wall rib spalling of the large mining-height working face of the shallow coal seam based on formula (3) according to the discriminant for tensile fracture ofthe equivalent immediate-roof stmtum