Dust Production Regualation And Optimization Of Dust Control In Tunnel Shotcrete Unloading Process

In view of the current phenomenon of "industry dust storm flow" at the unloarding point in the unloading operation of the roadway and the characteristics of dust generation,such as paroxysmal and instantaneous dust production,the integrated use of theoretical analysis,numerical simulation,orthogonal test,A variety of research methods,such as simulation experiments,took the cement in the raw materials needed for the preparation of concrete as the research object,and studied the dust production law of cement dust during the process of concrete unloading and the technical measures for dust control.Based on the analysis of the dust source and dust production mechanism of the dust generated by the intermittent discharge,the four factors that affect the dust production during the discharge process are as follows:unloading hopper and hopper structure,unloading height,unloading angle,and air flow in the roadway The pressure was subjected to orthogonal test design and nine groups of different process parameter levels were combined.The numerical simulation of the nine groups was performed using CFD numerical simulation software,revealing the influence of various factors on the diffusion of cement dust generated by the high discharge point of the breathing belt.It is preferable to design a better combination of process parameters.Since the spraying operation requires multiple unloading operations to be completed within a short period of time,in order to ensure that the spraying speed of the spraying machine can meet the requirements of the spraying operation,and in conjunction with the unloading mixing process,the preferred unloading process parameter combination is used.The numerical simulation of the dust production under the induced air flow mechanism was conducted.The two blanks were taken as the representative.The rules of the transport of cement dust from a blanking and secondary blanking were analyzed respectively,and the different discharge time intervals were compared and analyzed.After the completion of the secondary blanking,the cement dust migration rule was analyzed.The concentration of the dust in the height of the breathing zone was analyzed and the relevant linear equations were calculated and analyzed.The simulation results were the process configuration of the shotcrete unloading operation and the labor organization's Optimization design provides research methods and basis.Based on the analysis of the above numerical simulation results,a simulation experiment bench was established through similarity theory to design a discharge dust prevention and control program.Numerical simulation of discharging process parameters and numerical simulation of dust production by dust-producing dust were simulated and verified respectively,and compared with the experimental data of the field and the experimental results of the improved loose-leaf plate discharging mode.The consistency of the data and the rules indicated that the numerical simulation could be performed.Prediction and guidance of shotcrete unloading process.The experimental results show that the optimized unloading process,the grasping of the unloading interval time and the improved unloading mode of the unloading plate all can reduce the unloading dust production concentration,reduce the dust pollution in the concrete preparation process,and create a clean construction environment for the downhole concrete injection operation.