Underground Infrastructure Impacts Due to a Surface Burst Nuclear Device in an Urban Canyon Environment

Bos, Randall J.¹  Dey, Thomas N.¹  Runnels, Scott R.¹ 

[1] Los Alamos National Laboratory

关键词: BASEMENTS;    CANYONS;    COMMUNITIES;    EXPLOSIONS;    GEOMETRY;    MODIFICATIONS;    NEVADA TEST SITE;    PLANNING;    ROADS;    SHIELDING;    TESTING;    BUILDINGS;   

DOI  :  10.2172/1045394
RP-ID  :  LA-UR-12-22648
PID  :  OSTI ID: 1045394
Others  :  TRN: US201215%%189

学科分类：社会科学、人文和艺术（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Investigation of the effects of a nuclear device exploded in a urban environment such as the Chicago studied for this particular report have shown the importance on the effects from the urban canyons so typical of today's urban environment as compared to nuclear test event effects observed at the Nevada Test Site (NTS) and the Pacific Testing Area on which many of the typical legacy empirical codes are based on. This report first looks at the some of the data from nuclear testing that can give an indication of the damage levels that might be experienced due to a nuclear event. While it is well known that a above ground blast, even a ground burst, very poorly transmits energy into the ground ( < 1%) and the experimental results discussed here are for fully coupled detonations, these results do indicate a useful measure of the damage that might be expected. The second part of the report looks at effects of layering of different materials that typically would make up the near ground below surface environment that a shock would propagate through. As these simulations support and is widely known in the community, the effects of different material compositions in these layers modify the shock behavior and especially modify the energy dispersal and coupling into the basement structures. The third part of the report looks at the modification of the underground shock effects from a surface burst 1 KT device due to the presence of basements under the Chicago buildings. Without direct knowledge of the basement structure, a simulated footprint of a uniform 20m depth was assumed underneath each of the NGI defined buildings in the above ground environment. In the above ground case, the underground basement structures channel the energy along the line of site streets keeping the shock levels from falling off as rapidly as has been observed in unobstructed detonations. These simulations indicate a falloff of factors of 2 per scaled length as compared to 10 for the unobstructed case. Again, as in the above ground case, the basements create significant shielding causing the shock profile to become more square and reducing the potential for damage diagonal to the line of sight streets. The results for a 1KT device is that the heavily damaged zone (complete destruction) will extend out to 50m from the detonation ({approx}100m for 10KT). The heavily to moderately damaged zone will extend out to 100m ({approx}200m for 10KT). Since the destruction will depend on geometric angle from the detonation and also the variability of response for various critical infrastructure, for planning purposes the area out to 100m from the detonation should be assumed to be non-operational. Specifically for subway tunnels, while not operational, they could be human passable for human egress in the moderately damaged area. The results of the simulations presented in this report indicate only the general underground infrastructure impact. Simulations done with the actual basement geometry would be an important improvement. Equally as important or even more so, knowing the actual underground material configurations and material composition would be critical information to refine the calculations. Coupling of the shock data into structural codes would help inform the emergency planning and first response communities on the impact to underground structures and the state of buildings after the detonation.