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Session: Physical Modeling Issues of Site Effects

Type: Oral

Date: 10/12/2023

Time: 10:15 AM

Room: Stanley Park Ballroom

Consequences of Underground Explosions on Soil and Structures Using Non-linear Hydrodynamic Simulations: Application to the August-4-2020 Beirut Explosion

Predicting a propagating blast wave in urban environment is a complicated task especially when dealing with a dense and a complex urban environment such as Beirut city. Furthermore, when the shockwave is simultaneously interacting with sea water, air, and ground, then it further complicates the non-linear interaction of the shockwave with the environment and its response to the urban geometry and structures. Empirical and semi-empirical engineering tools are then limited, and it is required to use state-of-the-art hydrodynamic codes which has led us to develop a physics-based framework to seamlessly simulate the event from source, chemical explosion, to ground and sea-water impacts, to wave generation, propagation. The non-linear effects of the explosion are simulated using the hydrocode GEODYN to create the nearfield source for the shallow water wave propagation code, SWWP and the ground propagation SW4. The GEODYN-SWWP coupling is based on the structured adaptive mesh refinement infrastructure; SAMRAI developed at LLNL, while GEODYN-SW4 coupling is based on mapping the explosion source as a boundary condition to SW4. We illustrate both couplings and compare them to a direct solution where all the physics is solved fully using GEODYN. Only a fraction of the total explosion energy is converted into hydroacoustic and seismoacoustic waves that are propagated beyond the source region. The remaining energy is consumed by the “evaporation” of the water and pulverization of the surrounding ground and structures. We predicted the crater at ground zero and assessed key parameters and their uncertainty on the overall hydroacoustic and seismoacoustic responses. We also use a scaled versions of Source Physics Experiments (SPE) to assess the impact of underground and above ground explosions on nearby surface structure. Finally, we apply the end-to-end simulation framework to the August 4^th, 2020 Beirut explosion.

This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Presenting Author: Souheil M. Ezzedine

Additional Authors