Effects of Accidental Explosions on Low Stiffness Pipes Buried in Undrained Clay

 

Akinola Johnson Olarewaju

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

 

 

 

ABSTRACT

Low stiffness pipes are flexible pipes which are used for various services across the world. In this study, due to accidental explosions, the responses of various low stiffness pipes buried in undrained clay soil were observed.. Explosion load parameters for 250kg TNT explosive exploding at less than 10m away from the buried low stiffness pipes were determined using Unified Facilities Criteria (2008). The soil and pipe material properties were considered as elastic, homogeneous and isotropic. Material properties as obtained from various researchers and pipe manufacturers were used. Equation of motion was solved using time integration technique in ABAQUS/Explicit, a finite element numerical code. From the results of this study, displacement of buried low stiffness pipes due to underground accidental explosions is constant irrespective of the ground medium while at pipe stiffness of 300kPa, strain at the crown, invert and spring-line of buried low stiffness pipes is 0.00006. Remarkable response due to underground accidental explosions, in pressure and stress was noticeable at pipe stiffness of 100kPa and above while that of surface accidental explosions is noticeable at pipe stiffness 10kPa and above. For low stiffness pipes buried at low depth of burial, especially in undrained clay soil, there is need for explosion resistance evaluation. This is because materials yield more at lower depth of burial compared to deeply buried low stiffness pipes

Keywords: Explosion; Underground; Surface; Low Stiffness Pipes; Response, Undrained Clay.

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