Suitability evaluation method of high-strength materials for soft and strong double-layer composite support beside gob-side entry retaining

Abstract

The invention discloses a method for suitability evaluation of a high-strength material of a roadside flexible-strength double-layer composite support in gob-side entry remaining. The flexible-strength double-layer composite support is composed of an upper-layer padding body and a lower-layer padding body. A flexible material is adopted by the upper-layer padding body and a high-strength material is adopted by the lower-layer padding body. According to the method for suitability evaluation of the lower-layer high-strength material, deformation allowed by a roadway serves as a basis; with the combination of coordination deformation of the amount of compression of the padding bodies and the amount of compression of gangue, the coefficient of compressibility of the gangue in a gob is determined; the bearing capacity of the padding bodies is determined according to the compression performance of the high-strength padding material and the compression performance of the gangue in the gob, so that the compressive strength needed by the high-strength padding material is obtained, the actual compressive strength of the pre-selected high-strength material is compared with the compressive strength needed by the obtained high-strength padding material, and therefore the suitability of the pre-selected high-strength material is evaluated. According to the method for suitability evaluation, the bearing performance of the high-strength padding material and the bearing performance of the gangue in the gob are thoroughly considered, and the shortage that influence on the bearing capacity of the gangue in the gob by the amount of compression of the gangue in the gob is ignored in the prior art is overcome.

Description

technical field [0001] The invention relates to a method for determining the strength of a high-strength material for soft-strong double-layer composite support beside gob-side entry retaining, and belongs to the technical field of entryway support in mine goafs. Background technique [0002] Gobside retaining is a coal pillar-free mining technology, which has the advantages of alleviating the continuous tension of coal mining face, significantly improving the recovery rate of coal resources, and effectively prolonging the service life of the mine. key technologies. At present, there are mainly three types of roadside support for gob-side entry retaining at home and abroad, including artificial gangue belt and other roadside flexible filling bodies, roadside rigid filling bodies filled with rigid materials, and roadside graded filling and section bearing. The technology related to the present invention is roadside graded filling and segmented bearing method, which is a soft...

AI Technical Summary

Problems solved by technology

The compressive strength of the filling body beside the roadway mainly comes from the high-strength material in the lower layer. If the strength of the filling body is too small, the filling body will be destroyed under the action of the roof pressure, which will cause the deformation of the surrounding rock to lose control, resulting in the failure of the roadway retention; Although the effect of roadway retention can be guaranteed, the cost of filling materials will be greatly increased, and the economic benefit is poor

[0004] At present, most of the methods for determining the strength of the roadside filling body are designed for the first two roadside support methods. The defect of using these methods to design the filling body strength when the roadside is graded and segmented is that the upper and lower layers of filling The calculation of the filling body as a whole with the same performance does not take into account the early yielding effect of the flexible filling body, and it is considered that the filling body is always in the working state of "limited deformation"; it does not consider the change in the bearing performance of the filling body and the goaf gangue, and ignores the Quantitative relationship between filling body and gangue bearing capacity and its compression

Therefore, the determined strength of the roadside filling body is not accurate. Generally, it is much greater than the actual strength of the roadside filling body. Although it can ensure the safety of the roadway, it causes a lot of waste

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