| In order to improve the resilience of the six coal mines in Pingzhuang against exogenous fires,a simulation study of the resilience plan for pre-defined fires in the six mines was carried out.In order to prevent the occurrence of wind flow disorder during the disaster period,i.e.,the reversal of wind flow in the upstream ventilation side branch and the reversal of wind flow in the downstream ventilation main air path,which leads to the uncontrolled spread of smoke flow in the shaft,a combination of basic theoretical analysis,duct similar experiments,field measured data,and physical simulation is used to prevent the occurrence of wind flow disorder during the fire period and effectively limit the uncontrolled spread of smoke flow in the Underground tunnels.That has great significance.For a single duct experiment,by changing the duct inclination angle or fan air volume,to simulate the wind flow reversal of the main duct of the downstream ventilation fire,the sufficient not necessary condition that the wind flow reversal will not occur in the main duct is when the experimental duct inclination angle is less than 10°,and the fan air pressure is greater than 9v.For the local air network duct experiments,by changing the fan air volume,used to simulate the wind flow disorder in the side branch after the fire,the condition that the wind flow in the side branch does not reverse is that the fan provides the main duct air network air volume to be greater than 1.66 m~3/s.Combining with the field data of Liujia mine,the ventilation system of Liujia mine is digitally modeled,and TF1M3D software is used to simulate the mine ventilation system in the current production period and to fit the simulation with the measured ventilation resistance,which results in a total mine ventilation resistance of 1904.69 Pa,a total main ventilator air discharge of 87.16 m~3/s,a 2609 working face air volume of 27.75 m~3/s,the maximum error between the simulation debugging of ventilation parameters and the actual measurement does not exceed 3.4%,and the simulation results of the ventilation system of Liujia mine meet the requirements of engineering analysis,and the established mine simulation model can be used for the simulation of ventilation during the disaster period with preset fire sources.For the possible exogenous fire caused by the burning of conveyor tape in Liujia mine,an upstream ventilation fire in the 2609 working face of the second south mining area and a downstream ventilation fire in the transport downhill of the second west mining area were preset,and the data output from the simulation was compiled and analyzed for the change of air volume in the key branches,the spreading process of smoke flow in the whole network domain of the mine,and the change of CO concentration at the key nodes,etc.It was found that the upstream ventilation The air flow reversal in the side branch and the wind flow reversal in the downstream ventilation trunk airway led to the uncontrolled spread of smoke flow in the shaft,and the preplanned measures of pressure regulation and local counter wind method were set up respectively.For the two fires and the preplanned simulations,it was found that the weak wind flow area is the weak link in disaster control.In this regard,measures to turn the weak wind flow area into the main wind flow area were summarized,such as internal wind transfer in the mining area,increasing the total wind supply in the mining area within the tunnel,increasing the total air volume of the ventilation fan within the mine,or conducting local backdraft.The study of disaster prevention plans for pre-determined fires in Liujia Mine is of great significance in predicting the disaster process,formulating preplanned measures scientifically,and achieving disaster avoidance and mitigation.The Paper has 37 figures,5 tables and 68 references. |
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