Research on the critical spacing of natural smoke exhaust shafts in urban shallow buried tunnels
The spacing between vertical shafts can change the pressure difference inside and outside the shaft.When the pres-sure difference inside and outside the shaft is zero,tunnel fire smoke cannot be discharged,and the corresponding position of the shaft is the critical spacing between vertical shafts.Based on the theoretical analysis of the pressure difference between the in-ner and outer openings of the vertical shaft,a theoretical model of the critical spacing of the vertical shaft is provided,and then FDS simulation is used for simulation verification.The results show that setting vertical shafts can significantly reduce tunnel tempera-ture.When the distance between vertical shafts is a critical dis-tance,the temperature drop is close to 150℃,and the tempera-ture of personnel evacuation paths is below 60℃.The smoke ex-haust efficiency of vertical shafts is between 55%and 80%,which can effectively carry out smoke exhaust in vertical shafts;When the distance between vertical shafts exceeds the critical dis-tance,the smoke pressure inside the tunnel is less than the wind pressure at the outlet of the shaft,and the smoke exhaust effi-ciency of the shaft is less than 50%.
urban shallow buried tunnelsvertical shaft smoke ex-haustcritical spacing model for vertical shaftsnatural smoke ex-haust
NETL
NSTL
万方数据
维普
