In-Structure Shock Assessment of Underground Structures with Consideration of Rigid Body Motion

Abstract

The present study assesses the in-structure shock of an underground structure induced by a nearby subsurface detonation. Both the rigid body motion of the entirely buried structure and the local response of the structural element are considered in characterizing the in-structure shock.Soil-structure interaction, behaving as an interfacial damping, is taken into account and the effect of different surrounding soils is investigated. A response spectrum is plotted for assessing in-structure shock induced by a typical subsurface detonation and subsequently the safety of the internal facilities and equipments mounted on the buried structure is evaluated. For safety purpose, the protective structures are better constructed in a site with small acoustic impedance and large attenuation factor. Results show that the proposed in-structure shock assessment method is effective and can be used as a supplement to TM-5-855-1 and TM-5-1300.

In-Structure Shock of Surface Structures: A Theoretical Approach

“…In-structure shock is a kind of strong vibration induced by an external blast or ballistic load not damaging or lightly damaging the main structure but causing devices within the structure to fail [8]. In-structure shock of underground structures with rigid body motion taken into account is investigated [9]. Double-layer floor is proposed to successfully mitigate vertical shock of underground structures [10].…”

Numerical Simulation of Shock Response and Dynamic Fracture of a Concrete Dam Subjected to Impact Load

“…ABAQUS, LY-DYNA), major developments in understanding the structural responses and failure modes of concrete structures under blast load have taken place. Many researchers have conducted comprehensive experimental and numerical investigations related to the effects of explosions on building structures (Tian et al, 2008;Jayasooriya et al, 2011), marine structures (Jin, et al, 2011;Zhang et al, 2011), underground structures (Ma et al, 2011;Li et al, (2013), and bridge structures (Hao et al, 2010;Son et al, 2011). In the modeling of transient loading, it is very critical to describe the propagation velocity of the stress waves correctly.…”

In-structure shock assessment and mitigation of structures

“…Therefore in the present study, only the response of the structural member within the blast duration is investigated. Further, for a typical underground protective structure, the influence of the global rigid body motion (RBM) is not significant (Ma et al 2011) thus in the present study, RBM is not considered.…”

“…The mass of the front plate is significantly small compared to the total mass of the test system consisting of the plate, channel beams, wood blocks as well as the steel clamps and the marble plates shown in Fig. 6.3, therefore the influence of rigid body motion can be neglected (Ma et al 2011). The structural element nearest to the subsurface detonation is represented by the steel plate.…”

“…In all the previous study of in-structure shock of underground structures (Weidlinger and Hinman 1988;Alwis and Lam 1996;Ma et al 2011), the free field load of the soil-transmitted blast is assumed as an impulse with an instantaneous peak and a rapid linear decay, similar to the one induced by an airburst. In the occasions when the in-structure shock of underground structures is taken into account, the standoff distance is relatively distant and soil or backfill surrounding the structure is relatively soft, it is reasonable to take into consideration the rise time of the soiltransmitted blast load.…”