Method for arranging small coal pillar grouting hole based on genetic algorithm in large deformation gob-side entry driving

Abstract

The application discloses a large deformation gob-side entry driving small coal pillar grouting hole arrangement method based on a genetic algorithm, adopts a borehole peeping technology to detect distribution characteristics of internal deformation fissure and broken zone of the small coal pillar, and delimits a grouting reinforcement target area; the side wall of the coal pillar is simplified into a regular plane model, a safety coefficient is introduced to convert an effective diffusion radius in combination with actual diffusion characteristics of the slurry, then the minimum slurry diffusion range overlap degree and the maximum overall effective coverage area of adjacent grouting holes are taken as optimization targets, an intelligent optimization algorithm is used to iteratively solve optimal slurry diffusion radius and grouting hole arrangement parameters, and the hole diameter, hole depth, spacing and arrangement form are determined; a tilt grouting hole is additionally arranged in the deep broken zone, and peeping rechecking and additional hole drilling are carried out after construction. The application can accurately adapt to the reinforcement requirements of the broken small coal pillar, avoids grouting blank areas, reduces invalid slurry overlap, improves slurry utilization and coal pillar integrity, and is suitable for various small coal pillar grouting reinforcement engineering of gob-side entry driving.