Objective When cross passage fire doors in metro interval tunnels need to be dismantled and repaired due to damage or detachment, the replacement cycle is generally about 2 to 3 months. During the dismantling and repair period, airflow between the left and right tunnels becomes interconnected, which in turn affects the ventilation performance for accidents in interval, and the original tunnel ventilation mode may fail to meet specification requirements. Therefore, it is necessary to study dismantling and repair schemes for cross passage fire doors in metro interval tunnels based on emergency ventilation requirements.

Method Taking a long-large interval of a metro line in Wuhan as the study case, the general conditions are briefly described. The ventilation and smoke exhaust standards for metro intervals and the ventilation scheme of the case interval are introduced. A numerical calculation model is established using SES (subway environment simulation) software to determine the most unfavorable fire scenarios in each ventilation section of the case interval. Based on the simulation results of three ventilation sections in case interval, a detailed analysis is conducted to assess whether the cross-sectional smoke exhaust air velocity in different dismantling and repair schemes meets specification requirements under the most unfavorable fire conditions. Reasonable dismantling and repair schemes for cross passage fire doors in each ventilation section are proposed.

Result & Conclusion  It is recommended that cross passage fire doors be dismantled and repaired in groups according to ventilation sections. For ventilation sections with three or less cross passages, the original tunnel ventilation control scheme can be adopted. When there are two cross passages, dismantling and repair works should be carried out one by one; in case of three cross passages, no more than two fire doors should be dismantled and repaired simultaneously. For ventilation sections with four cross passages, since the original tunnel ventilation control scheme cannot meet the ventilation and smoke exhaust requirements, the tunnel fans need to be additionally activated to assist ventilation and smoke exhaust. The specific ventilation control scheme should be determined through simulation calculations.