Mitigating ground shocks with cellular solids

Underground structures are sometimes threatened by ground shocks induced by subsurface detonations. This paper proposes one possible method to mitigate the subsurface blasts by attaching a cladding consisting of a face sheet and cellular solid core to the exterior of the structure; the cellular core is foam made from relatively strong materials, such as metal or concrete, rather than typical geofoam made from polymer. A simplified model is established to distinguish three scenarios to delineate the dynamic behavior of a foam cladding subjected to a ground shock. The model compares the velocity time histories of the face sheet and the surrounding soil, in which the foam crushing velocity is not high and the foam is densified uniformly. Further, the governing equations for possible high-velocity foam crushing are established, with progressive collapse as foam crushing mode when alleviating subsurface blasts. © 2013 American Society of Civil Engineers.