Prediction and Assessment of Loads from Various Accidental Explosions for Simulating the Response of Underground Structures using Finite Element Method

 

Akinola Johnson Olarewaju

Civil Engineering Department, School of Engineering, Federal Polytechnic Ilaro, P.M.B. 50, Ilaro, Ogun State, Nigeria
e-mail: akinolajolarewaju@yahoo.com or akinolajolarewaju@gmail.com

 

 ABSTRACT

In model study of soil-structure interaction due to accidental explosions, experimental, analytical and numerical results are required. These are better obtained from field tests, laboratory tests, work done and extension of work done in related fields, as well as theoretical and model studies. To simulate the response of underground structures due to various accidental explosions, rock and/or soil media, structures, intervening medium surrounding the structures, loads from accidental explosion and explosion characteristics are required. In this study, empirical, semi-empirical and numerical methods of predicting loads from various accidental explosions for studying the response of underground structures were discussed. In addition, numerical codes for predicting loads from accidental explosions were equally discussed. Furthermore, different types of accidental explosions as well as loads from accidental explosions ranging from 10kg TNT to 10,000kg TNT equivalent were considered using Unified Facilities Criteria (2008). Trinitrotoluene equivalents for different explosives were also considered. Consequently, ground movement parameters were estimated at various stand-off distances for the given range of loads from accidental explosion using the empirical code for hemispherical wave front. The parameters thus estimated include; displacements, velocities, accelerations, peak reflected pressures, peak overpressures, arrival time, etc. for surface accidental explosions and underground accidental explosions. For the types of accidental explosions considered, it was observed that the ground shock parameters attenuate greatly as the distance from the accidental explosion increases. In addition, the arrival time increases more in saturated clay as the distance increases compared to sand. Parameters thus determined would help in simulating the response of underground structures due to various accidental explosions using numerical codes like ABAQUS, etc. and in designing underground structures specifically pipes to resist the effects of various accidental explosions. Consequently, the environmental risk and hazards caused by accidental explosions would be greatly reduced if not completely eliminated.

Keywords: Accidental Explosions, Characteristics, Hazard, Underground Structures, Response Movement, Finite Element.

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