SBIR-STTR Award

An innovative and cost-effective approach is presented for development of explosive safety (Quantity-Distance) criteria for shallow tunnels. The approach proposes to formulate and validate the Scaling Laws for Q-D incorporating properties of explosives, as well as the physical and mechanical characteristics of engineering systems, i.e. concrete, steel reinforcing elements, etc.; and geologic systems, i.e. soil and rock mass hosting the structures. The formulated scaling laws are then validated through a series of large-scale tests. The design of test specimens are based on scaling length, time, and force (mass) such that similitude conditions are maintained between the model and actual structure to facilitate the ease of interpolation of the obtained results to predict prototype response. Most of the effort in Phase I is concentrated towards engineering analysis of one-g scale model, identification of pertinent parameters for formulating the scaling laws and planning the test matrix for concept validation. The proposed research investigation provides a powerful approach for developing explosive safety criteria and a unique and cost-effective approach for concept validation

Application of physical modeling will be extended to verify the Bakhtar's Explosive Safety Criteria formulated in the Phase I study. Similitude conditions will be employed to cast the large scale test specimens representing crystal blocks with defined geology and associated model structures, i.e. access tunnel and attached chamber. The main theme of the proposed study will be centered on the evaluation of the hazardous effects of the NS verification approach will be done in such a way that the properties of the geologic system (rock mass with the associated discontinuities) hosting the underground facility, and the engineering system (structural components of the tunnel and attached chamber) are decoupled in the material characterization, modeling, testing, and analysis. Therefore, once the formulated criteria is verified, it can be used for safety assessment of the existing facilities, safe design of the future facilities, and by neglecting the geologic terms, for hardness assessment of the aircraft shelters