Ground motion analysis of OSSY
- Los Alamos National Lab., NM (United States)
The On Site Seismic Yield experiment, OSSY, was performed to investigate the viability of a high-explosive technique to help estimate the yield of nuclear explosions. We have analyzed recorded data and conducted numerical simulations of the 100-pound OSSY experiments performed in hole UE-10 ITS No. 3 at the Nevada Test Site. Particle velocity wave forms from these experiments show a distinct dual-pulse structure in the close-in and far-field regions, with the amplitude of the second pulse being as large as or larger than the first pulse. To gain some insight into the cause of the dual-pulse feature, we examine how the explosion-induced close-in response is affected by (1) certain features of inelastic rock/soil constitutive models applied in the near-field region, (2) the large length-to-diameter charge ratio of 8, (3) the charge and gauge package emplacement, and (4) geology (e.g., layering) in the vicinity of the explosion. Our results from 1-D and 2-D simulations show the following: (a) the response, measured by accelerometers located above the charges, is significantly influenced by the charge length-to-diameter ratio out to a distance of 8 m. (b) the grout emplacement of the charge has very little effect on the response. (c) the geologic layering serves mainly to phase the arrival of the pulses. (d) the second pulse can be best accounted for by applying a dilatant feature that allows for pore recovery during unloading. Other material property variations do not provide any contribution to the formation of a second pulse.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 91003
- Report Number(s):
- LA-UR-93-3839; CONF-930397-; ON: DE95003509; TRN: 95:018300
- Resource Relation:
- Conference: Numerical modeling for underground nuclear test monitoring symposium, Durango, CO (United States), 23-25 Mar 1993; Other Information: PBD: Nov 1993; Related Information: Is Part Of Proceedings of the Numerical Modeling for Underground Nuclear Test Monitoring Symposium; Taylor, S.R.; Kamm, J.R. [eds.]; PB: 404 p.
- Country of Publication:
- United States
- Language:
- English
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