System and method for monitoring reserved coal pillaralong-goaf remained gateway floor crack development

Abstract

The invention discloses a system and method for monitoring reserved coal pillaralong-goaf remained gateway floor crack development. A floor drill site is dug in one side of a reserved coal pillaralong-goaf remained gateway, different depths of drilling is conducted on a floor, and a butt joint sealing system is adopted to deliver transparent hollow pipes to drill holes in a section-by-section butt joint mode; after casting is conducted in gaps between the drill holes and the transparent hollow pipes for anchorage, a detecting and positioning assembly is utilized to record surrounding rock gaps of the drill holes at different positions on a measuring ruler, and floor's mining fracture law evolution monitoring tasks are carried out at different mining stages for multiple times till data trends to stable observation finishing. According to the method, floor shallow part drill holes, floor middle deep drill holes and floor deep part drill holes extending from the floor drill site to the mining coal floor and arranged side by side are arranged in a stereo mode, the middle floor plastic failure zone developmental morphology during mining and floor failure zone developmental morphology can be delineated by observing the adjacent drill holes and the gap situations of the same drill holes at different coal mining stages at the same time, and reliable data reference can be provided for safe construction.

Description

technical field [0001] The invention relates to a system and a method for monitoring the development of fissures in the bottom plate of gob-side entry retention of reserved coal pillars, belonging to the field of mine support. Background technique [0002] The distribution of my country's coal resources is very regional. At present, about 90% of coal resources are produced in North China coal fields. The severe form of mine water damage has seriously affected the safe production of my country's coal mines and restricted the steady and healthy development of the national economy. The development of coal fields has a great impact on the national economy. development is important. At the same time, the hydrogeological conditions of many coal fields in our country are very complicated, and the coal seam mining process is threatened by various water bodies. The coal reserves threatened by karst water in the main mining areas in the north alone are about 15 billion tons, accounting...

AI Technical Summary

Problems solved by technology

The gob-side retaining in these two cases will cause the shallow floor drilling to collapse. Even if the protective wall casing is lowered to a certain depth, there will still be collapse holes in the monitoring section (without protective wall casing), and once If a collapsed hole occurs, it is difficult to repair it again. The only way is to re-drill the hole, which is not only time-consuming and labor-intensive, but also more likely to miss the best observation time;

[0006] (2) Coal seam floor strata are generally divided into hard rock strata, soft rock strata, and soft and hard rock strata. Water softening, if the data is not observed in time, the soft rock section of the drill hole may automatically close or collapse in a short period of time, making the drill hole invalid and having to re-drill the drill hole, or even re-drill the drill hole several times, greatly increasing the monitoring Cost; at the same time, the frequent replacement of boreholes results in not only the inability to effectively collect available data, but also no reference comparison for the macroscopic changes of cracks at the same position at different times, and the reliability of the detection results is very low

[0007]

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