Effect of explosions in tunnels - Preliminary assessment of the structural response

Abstract

Background Nowadays goods which are sensitive for explosion are transported along alternative routes that exclude tunnels. These are mostly secondary roads. The transport along these alternative roads has many disadvantages, such as the safety along the route, the air- and noise pollution along the road and the higher transport costs. Therefore, it is preferred to permit the transport of dangerous goods through tunnels. In case of multiple use of space this leads to the question what are the possible consequences and risks for buildings of structures above the tunnel. In the Delft Cluster work package “Bijzondere Belastingen” (CT01.21) the consequences of an accident with a transport of explosion hazardous goods are considered: BLEVE1 and gas explosion. These phenomena have a low probability of occurrence, but might have immense consequences. Therefore, a deterministic consideration is not possible. The results of the work package must facilitate the quantitative risk analysis of the phenomena, which supports the authorities in their decision of allowing transport of dangerous goods through tunnels or not. The work package focus is on the mechanical description of the loading and the response. However, it requires an interdisciplinary approach, which integrates knowledge of risk analysis, explosion and evaporation of liquefied gases, structural dynamics and soil dynamics. Project description The work package contains two main stream research lines: 1. Loading due to BLEVE (Boiling Liquid Expanding Vapor Explosion) and gas explosion. The BLEVE research is mainly executed in a PhD project at Delft university of Technology. This part focuses on an improved understanding and modeling of the BLEVE phenomenon. TNO Defense and Safety will participate in this research line by introduction of practical mechanical modeling of the vessel behavior and creation of a practical engineering model for BLEVE load prediction, based on the results of a PhD-study. 2. Dynamic Response of the structure-soil system under BLEVE and gas explosion loading. Here TNO Built Environment and Geosciences concentrates on the structural part of the problem, whereas GeoDelft and Delft University of Technology will take care of the soil response. TNO Defense and Safety will provide data on appropriate loads for realistic cases.