Investigation of Environment and Response Phenomena for Buried Target Structures in Crater Margins

摘要

There are situations in which peak overpressure on the surface may be a conservative or even a misleading kill criterion. To kill structures which are hardened to withstand the effects of several thousand psi overpressures may require such small miss distances for a blast-only kill that the structure will be within or very near the crater. Other effects - notably direct ground shock and cratering action will then become substantial, if not overwhelming, factors in the structure kill. This report concludes: (1) Using simulated MIDDLE GUST III dynamic environment, response of representative structures at various ranges near the crater were analyzed. For example, the MX-B vertical shelter (l/d = 7) is predicted to be destroyed in the crater margin due to decoupled effects of peak ground shock pressure (crushing), dynamic ground shock gradient (plastic hinge), and late-time differential displacement (plastic hinge). (2) Distinct layering in the MIDDLE GUST III geology (probably typical of many target sites) substantially affects structure vulnerability to dynamic ground shock gradient and late-time differential and late-time differential displacement from cratering flow. (3) Environment near nuclear craters will be more severe than near HE craters, due to effects of 5-10 times higher peak overpressure at crater radius. Thus, HE sources alone will not simulate the combined environment effects near nuclear craters. (4) If test sites which are chosen have no strong relective interface at a relatively shallow depth, the near-crater environnent for model structures will probably not be as severe as for full-scale structures near nuclear craters in typical layered geologies.