High-pressure grouting technology of water-rich weathered fractured strata under thick loose strata for coal mines

Abstract

The invention relates to a high-pressure grouting process of a water-rich weathering fracture rock formation below a thick unconsolidated formation for a coal mine. The process at least comprises the following steps of A) pipe fixing grouting, B) secondary drilling, C) grouting core pipe mounting and D) high-pressure grouting. Therefore, a thin grouting core pipe is tripped in a grouting hole, clearances are formed among the grouting core pipe, a secondary drilled hole and an orifice pipe, a pipe fixing and grouting stopping device is arranged on the front segment of the grouting core pipe, the pipe fixing and grouting stopping device is filled with pipe fixing materials, a thick pipe fixing layer can be formed, the pipe fixing materials cannot enter the stratum below the grouting stopping device, and it is guaranteed that the section of a grouted layer is fresh and is not polluted by pipe fixing liquid. The physical, chemical and mechanical property of the formed pipe fixing layer is stable, the continuity of the pipe fixing layer in the clearances is good, few defects exist, large grouting pressure can be borne, construction efficiency is greatly improved, grouting efficiency is high, grouting cost is low, the grouting effect is good, and the process can adapt to fast water plugging of water burst accidents.

Description

technical field [0001] The invention relates to the technical field of water prevention and control in coal mines, in particular to a high-pressure grouting process for water-rich weathered cracked rock formations under thick loose layers used in coal mines. Background technique [0002] Coal mines often face the outbreak of various disasters during roadway excavation and mining operations, and water inrush disasters are one of the main ones. There are many types of geological structures that are prone to water inrush, and one of the geological structures is the coal seam. The formation has water-rich weathered fractured rock strata, and there are hard rock layers and thick loose layers on the water-rich weathered fractured rock stratum. The water in the water-weathered fractured rock formation will easily be introduced into the goaf, thus causing water inrush disasters. [0003] Water inrush is one of the most serious mine disasters, second only to gas disasters in the fie...

AI Technical Summary

Problems solved by technology

[0006] However, in this conventional grouting method, if the grouting pressure is not too high, the grout will emerge from the surrounding loose layer or the gap between the orifice pipe and the hole wall, resulting in grouting failure

Continuously changing the length of the orifice pipe entering the underlying formation of the loose layer cannot avoid the occurrence of slurry phenomenon

Through long-term practice and analysis by the inventors of the present invention, it can be considered that this situation is caused by the insufficient thickness of the solid pipe material between the orifice pipe and the hole wall, and the presence of solidified unsaturated regions or discontinuous regions. During high-pressure grouting, these areas are easy to be broken down, so that the grout flows to the ground through the loose layer, and it is impossible to grout the weathered fractured rock formation, so that the grouting hole is scrapped

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