天然气爆炸对盾构隧道的作用机制及工后修复

为了使爆炸灾害后的盾构管片得到合理的修复方案,以某地铁盾构施工过程中挖破天然气管道导致爆炸事故为背景,通过介绍爆炸的基本特性、冲击波的传播特点及火焰波的伴生关系,归纳在天然气爆炸过程中,爆炸火焰和冲击波是决定事故危害程度的2个主要因素,同时这些因素中最危险、破坏力最强、破坏区域最大的是冲击波的破坏效应。通过计算隧道内满布天然气时的TNT当量,以及采用拟静力法模拟管片内部的超压分布并计算得到管片的变形,与第三方检测数据中的管片变形指标进行耦合,证明模拟的准确性,为提出合理的区间修复方案提供依据,同时也为类似工程事故的处理和预案提供经验。

Acting Mechanism of Natural Gas Explosion to Shield Tunnel and Repairing Work

The basic characteristics of explosion, propagation characteristics of blast wave and the associated relationship of flame wave are presented to get rational repairing scheme for shield segment after explosion disaster. The explosion flame and blast wave are the main factors to the dangerous degree decision during natural gas explosion; and the damage effect of blast wave is the most dangerous. The trinitrotoluene (TNT) equivalent is calculated under condition of tunnel full of gas; the internal overpressure distribution of segment is simulated by imitated static method, by which the segment deformation can be calculated; the segment deformation calculated is couples to monitoring data to verify the accuracy of the simulation results. The results can provide guidance for rational tunnel repairing works and similar disasters in the future.