Experimental study on pulse gas presplitting grouting in water-rich muddy silt layer in open-pit coal mine
FENG Yan
ZHANG Yanbo
YANG Qinglong
XU Yanbing
ZHANG Lei
HOU Ning
Abstract：To address the challenges of non-uniform grout diffusion and the difficulty in forming a continuous water cutoff curtain in water-rich muddy silt layers of open-pit coal mines,a novel method combining high-pressure pulsed gas pre-splitting for soil layer with pressure grouting was proposed and implemented in a pilot project of Chaoyang Open-pit Coal Mine in Heilongjiang Province.A discrete element method(DEM)model based on fluid-solid coupling theory was developed to investigate,from a mesoscopic per-spective,the influence of pulsed gas parameters(pressure and frequency)on soil fracture propagation.By integrating the geological characteristics of the stratam,the optimal pulsed gas parameters were determined.Field grouting tests were conducted using a self-developed pulsed gas pre-splitting grouting control system,and the grouting effectiveness was systematically evaluated through field monitoring data,core sampling tests,and water pressure tests.The results demonstrate that high-pressure pulsed gas significantly en-hances fracture density in muddy silt layers,with the fracture growth process categorized into three distinct stages:rapid growth(Stage I),slow growth(Stage Ⅱ),and stabilization(Stage Ⅲ).The effective fracture propagation range exhibits a positive correla-tion with gas pressure,while showing an initial increase followed by a decrease with the increasing of gas frequency.The optimal gas parameters were identified as a pressure of 2 MPa and a frequency of 2.5 Hz.The pulsed gas pre-splitting grouting technology effect-ively reduces grouting pressure,increasing grout volume by 24%in loose sand layers and 92%in silty sand layers,with a maximum diffusion radius of 2 meters in open-pit mine strata.This method significantly improves the injectability of low-permeability silty sand layers and achieves exceptional anti-seepage and water cutoff performance.
Keywords：open-pit minewater-rich muddy silt layerpulsed gaswater cutoff curtainsplitting and fracturingcurtain grouting
Publication Date：2026-02-20
Online Publishing Date：2026-03-19(First online date of this platform, not the publication date of the document)
Pages：11( 189-199 )