Modeling of the Drift and Accumulation of Tsunami-Driven Combustible Objects: Towards Tsunami-Induced Fire Spread Simulation
Modeling of the Drift and Accumulation of Tsunami-Driven Combustible Objects: Towards Tsunami-Induced Fire Spread Simulation
复制标题
海啸驱动的可燃物体的漂移和堆积建模：走向海啸引发的火灾蔓延模拟
DOI：
10.1007/s10694-015-0519-5
复制
发表时间：
2016
期刊：
影响因子：
3.4
通讯作者：
Y. Imazu
中科院分区：
文献类型：
--
作者：
T. Nishino;Y. Imazu
在海啸淹没区发生的火灾被统称为“海啸引发的火灾”，而“地震引发的火灾”通常在日本受到严重关注。这种新火灾的基本情况是：（1）房屋等可燃物被海啸冲走，（2）可燃物在海啸淹没区堆积成碎片，（3）碎片因某种原因被点燃，（4）火灾蔓延到邻近的碎片，导致海啸淹没区发生火灾。我们一直在为海啸引发的可燃物体建模，作为海啸引发的火灾蔓延模拟发展的第一步。该模型旨在了解可燃物在海啸淹没区的积聚情况，并将其作为火灾模型的输入数据，用于点火和火灾蔓延。该模型是现有浮木模型的扩展，结合了碎片释放模型和碎片与幸存建筑物碰撞的影响。该模型与现有的海啸数值模拟相结合，能够通过求解水平平移运动方程来预测单个碎片的漂移和堆积行为。在本文中，我们进行了碎片扩散模拟山田，岩手县，日本模型的验证，其中16公顷的地区受到海啸引发的火灾蔓延后，2011年东日本大地震海啸。模拟中跟踪的碎片总数为1，850，560个。一个常数的比例，这决定了严重程度的力量作用于漂流碎片，由于与岸上幸存的建筑物碰撞，确定了试错，以最大限度地增加最终数量的积累碎片在火灾破坏区。结果，在常数为0.1的情况下，预测该最大量为4654吨。在计算结束时，释放的碎片中有三分之二（约12 000吨）积聚在岸上，大部分火灾破坏区都被这些碎片覆盖。
Fires that break out in tsunami inundation areas are collectively referred to as “tsunami-induced fires” in contrast with “seismic-induced fires” which have been conventionally a serious concern in Japan. Scenario of this new fire is basically as follows: (1) combustible objects such as houses are washed away by a tsunami, (2) combustible objects accumulate in tsunami inundation area as debris, (3) debris are ignited by some kind of cause, and (4) fires spread to adjacent debris resulting in conflagration in tsunami inundation area. We have been modeling tsunami-driven combustible objects as the first step towards development of tsunami-induced fire spread simulation. This modeling aims to know how combustible objects accumulate in tsunami inundation area to be the input data to fire models for ignition and fire spread. The proposed model is the extension of the existing model for driftwood by incorporating the debris release model and the effect of debris’s collision with surviving buildings. This model collaborates with the existing numerical simulation of tsunamis and is able to predict the drift and accumulation behavior of individual debris by solving the equation of horizontal translational motion. In this paper, we conducted debris diffusion simulation for Yamada, Iwate prefecture, Japan for model’s validation, where 16 ha of area were affected by tsunami-induced fire spread after the 2011 Great East Japan Earthquake Tsunami. The total number of debris tracked in the simulation was 1,850,560. A constant of proportionality, which determines the severity of force acting on drifting debris due to the collision with onshore surviving buildings, was identified by trial and error to maximize the eventual amount of accumulating debris within the fire-damaged zone. As a result, this maximum amount was predicted to be 4654 tons in the case that the constant is 0.1. Two thirds of the released debris, about 12,000 tons, accumulated onshore at the end of computation, and most of the fire-damaged zone was covered by these debris.