| In 2017,the General Office of the State Council issued the "Opinions on Promoting the Sustainable and Healthy Development of the Construction Industry".The "Opinions" clearly stated that the construction industry must meet the requirements of green,safety and economy.With the rapid economic development of southwestern cities,the mileage of urban subways has shown a blowout growth.Take Guiyang as an example.As of April 2020,the length of the line35.11 km has been opened and the length of the line under construction is 116.32 km.When using a cantilever roadheader for construction,it has the advantages of less disturbance to surrounding buildings and surrounding rocks,flat excavation section for initial support,high excavation efficiency,timely support,and reduced excavation time.However,the use of cantilever tunneling machines in the construction of tunnels will generate a lot of dust,which will seriously endanger the physical and mental health of the on-site construction personnel.To ensure the occupational health of the tunnel construction personnel and improve the safety and construction efficiency of the tunnel construction site,the working area of the tunnel construction personnel must be addressed The dust concentration exceeds the national health standard several dozen times.At present,atomization dust control technology is one of the most effective technical ways to control the problem of tunnel dust pollution.Therefore,improving atomization dust control technology plays an important role in the safe construction of tunnels.This article mainly uses a combination of theoretical analysis,experimental demonstration,numerical simulation,and field application.The main research contents are as follows:(1)With reference to the gas-solid two-phase flow theory,the subway section tunnel model is established,and the boundary conditions of the model are solved.FLUENT is used to simulate and analyze the dust diffusion mechanism and dust concentration distribution law of tunnel driving.(2)According to the "Sampling Regulations for Monitoring of Hazardous Substances in the Air at Workplaces"(GBZ 159-2004),relevant field tests and laboratory analyses were carried out on the dust concentration and dispersion of each working surface of the Huahua section tunnel of Guiyang Metro Line 3,and used The Rosin-Rammler distribution mathematical model solves the dust particle size distribution function of its model,and gives the best dust control position for each dust particle size range.(3)In the laboratory,carry out experimental research on the tunnel model based on the three-phase coupling of gas(air flow)-solid phase(dust particles)-liquid phase(fog droplets)to analyze the influence of different wind speeds and air supply pressures on dust control efficiency Laws to obtain better environment and equipment parameters.(4)On the basis of the experimental research data of the gas-dust-fog three-phase coupling tunnel model,carry out the numerical technology research of the tunneling dust segmentation blocking technology,and discuss the dust removal effect of the three sections with different first-stage dust control system placement and spray pressure.(5)Comprehensive analysis of the numerical analysis data and field application effects of the three-section spray dust control system to verify the correctness of the numerical analysis results.The research results are helpful for the parameter optimization of the spray dust control system,the improvement of dust control devices,and the evaluation of dust reduction efficiency.It provides a certain theoretical basis for the application of spray dust control in the process of tunnel excavation,and has very important guiding significance for the optimization of the tunnel site dust control effect. |
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