Test bed for measuring compaction characteristics of coal seam roof caving natural renewal

Abstract

The invention discloses a test bed for measuring compaction characteristics of coal seam roof natural renewal. The test bed is mainly composed of a bed body and a bed cap, the bed body is formed by welding a shell and a base, and the body cap is formed by welding a compaction body and a loading plate. In the process of use, a miniature stress sensor is fixed to coal gangue at the bottom of the bed body, roof rock samples are laid in the bed body according to a certain proportion, the bed cap is arranged in a covering mode, the balance weight is loaded on the loading plate according to design weight, and compaction characteristics of dispersed rock blocks are simulated; vertical stress change in a model is monitored through the miniature stress sensor, and change of the void ratio of dispersed bodies is calculated by measuring the deflection of the dispersed bodies. After the compaction process is completed, a drawing strip at the bottom of the bed body is drawn out to change the hanging area of the compaction model, and the caving situation at the bottom of the model is observed; afterwards, coring is performed on the compaction model, and the strength of the compaction model is measured through a compression test. The test bed is a testing tool for measuring the cementation degree and the compaction characteristics for layered mining of regenerated roof in a thick coal seam, and has certain practicability and novelty.

Description

technical field [0001] The invention relates to a testing platform for measuring the compaction characteristics of natural regeneration of coal seam roof caving, which can measure the cementation degree and compaction characteristics of the natural regeneration roof of coal seam layered mining, and is used to guide the mining of coal seams under the natural regeneration roof. Background technique [0002] In thick coal seam layer mining, no artificial net is laid on the floor when the upper layer is mined, so that the roof is a regenerated roof formed by the natural fall of the upper layer and compaction and cementation when the lower layer is mined. In order to ensure the safe and stable mining of the lower layer , the degree of cementation and strength of the regenerated roof needs to be tested in the laboratory. Due to the fact that previous scholars have not done much research in this field, there are not many types of instruments for discrete body compression tests. Tw...

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Problems solved by technology

The two instruments in soil mechanics are used to perform compression tests on the compressibility characteristics of soil samples. Although the "consolidation instrument" can measure the compression index of rock blocks, it cannot test the overall stability and cementation of compressed rock samples. The degree and strength indicators are measured; while the "compaction instrument" is not suitable for the compression of rock blocks, and the rock blocks will be crushed during hammering, which loses the meaning of discrete rock block compression; the patent "coal mine old goaf The Secondary Deformation and Compaction Simulation Experimental Device for Broken Rock Mass in the Caving Zone in the Caving Zone only conducts simulated compression tests on broken rock blocks under the action of load and water injection, and obtains the stress-strain law of the broken rock mass, which cannot Under the action of load, the regeneration roof is formed for research, and the overall stability, cementation degree and strength index of the compressed rock block cannot be measured.

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