Research On The Deposition And Migration Law In Water Inrush Channel Of Coal

The construction of mines or tunnels and other underground projects is often necessary to traverse the water-rich areas,which seriously affects the safe construction and future operation of the project.Using the borehole grouting method can be effectively managed water breakthroughs in a short time and help the enterprise to resume normal production as soon as possible.The process of grouting to block water inrush is generally filling the aggregate to build a water barrier wall,firstly,to reduce the flow rate and the area of flowing cross-section before grouting and reinforcing.Therefore,it is necessary to study the law of aggregate deposition and migration,which can help workers rapidly construct water blocking.In this paper,a combination of theoretical analysis,laboratory experiments,and numerical simulation are used to conduct an in-depth study in the experiment of aggregate interception control in the small flow and high-velocity rates of the water inrush channel of coal.The main research contents and achievements are as follows:(1)Based on slurry pipeline transportation and sediment mechanics,a model for the deposition and migration of aggregates during the interception process of the water inrush channel is established.According to the force characteristics of the aggregate deposition in the water inrush channel,combined with the kinetic energy theorem and the mechanical equilibrium equation for theoretical derivation,to establish the aggregate deposition and migration model,the model takes into account the aggregate’s diameter,channel width,perfusion height,and other factors in the influence of the aggregate diffusion distance,the calculation formula of aggregate’s start-up when the water inrush channel is blocked and about to reach the top is deduced,which provides theoretical guidance for the water inrush channel aggregate plugging.(2)Design of a simulation experiment platform for aggregate deceleration and cut-flow.The experiment platform is composed of five parts: water-supply system,piping system,aggregate perfusion system,data and image acquisition system,and aggregate recovery system.The platform can simulate flow interception and blocking experiments under the influence of different dynamic water flow rates,perfusion material,channel width,and perfusion height,and collect real-time images of aggregate accumulation,diffusion patterns,channel pressure data,etc.(3)Simulation experiment of aggregate deceleration and cut-flow.Through the orthogonal experiment method,revealing the influence of dynamic water flow rate,aggregate particle size,perfusion height,and other factors on the water sealing effect of the aggregate and its primary and secondary relationships;expanding the study of channel pressure change during aggregate infusion;study on the repose angle of aggregate under anhydrous and hydrostatic conditions,by comparing and analyzing with the results of orthogonal experiments to clarify the relationship between the aggregate accumulation form and repose angle during the plugging process;established criteria for the selection of aggregate particle size for different dynamic water flow rates;the optimum spacing of the aggregate perfusion holes under different working conditions was determined;the influence of different perfusion sequences of aggregates on the sealing effect was investigated by the comprehensive test method.(4)CFD-DEM coupling method was used to carry out the simulation experiment of aggregate deceleration and cut-flow inrush water.Firstly,the geometric models of particles and pipes were established,and parameter settings were made in the software,then the experiment of simulating aggregate sealing water inrush channel under different conditions was carried out,finally,the simulation results were compared and analyzed with the laboratory experiment results,and the analysis results further reasonably supplemented and improved the laboratory experiment conclusions.