Debris field

Debris Field at a Third Glenbrook Road Property... 

After workers were sickened digging up several chemical bottles while planting a tree on a Glenbrook Road property. Apex Enviromnental performed an environmental survey of the property. Arsenic at 1200 ppm was found in the hole, confirming that at least one of the bottles contained chemical warfare agent. The District of Columbia viewed one of the bottles and it appeared to date to around 1918. Acid readings were detected at two places on the property, and a debris field was noted in the rear of the property. The recent geophysical study has also noted metal anomalies in the rear of the property and under the driveway. Any anomalies and the debris field on this property should be excavated. 

In addition, the high quality of the submarine components required by SUBSAFE, along with intensified structural inspections, had reduced the availability of critical parts such as seawater piping [8], A year later, in May 1968, Scorpion was lost at sea. Although some have attributed its loss to a Soviet attack, a later investigation of the debris field revealed the most likely cause of the loss was one of its own torpedoes exploding inside the torpedo room [8]. After the Scorpion loss, the need for SUBSAFE was reaffirmed and accepted. 

As a basis for evaluating the physical effects of the explosion, the damage pattern was recorded by topographical maps, terrain sections, and aerial as weU as terrestrial photos. Detailed documentation was elaborated for 53 pieces of large single debris and 40 debris collection fields [8]. The data from these debris fields were used for evaluating the debris throw from the crater, which is described in detail here. 

The following were the main steps necessary for the recovery of the debris field dafa ... 

Finally, all pieces of debris were collected and sorted out according to different materials (rock, concrete, metal parts, etc.), and size. Figure 26.11 shows an example. The debris were counted and weighed. A data sheet was prepared for each debris field, showing all details, and, as a first step in the evaluation, the debris mass density in kg/m was calculated (Fig. 26.12). Figure 26.13 gives an overview of the data of all debris fields. 

For the evaluation of the debris throw from the crater, only debris fields nos. 81 to 95 and 109 to 116, (a total of 23) were used. Together with the fact that the maximum crater debris throw distance was on the order of 600 to 700 m, the graph in Fig. 26.14 was developed. This shows the debris mass density in relation to the distance from the center of the crater. Although the data scattering was not as small as one would have liked it, this debris mass density versus distance curve represented the physical facts reasonably well. Based on this curve, the debris mass density contour lines in Fig. 26.15 could be drawn. 

This curve does not yet show an angular dependency of the crater debris throw. Although some of the debris fields sideways to the axis showed somewhat smaller debris mass densities, it was decided at that time, because the number of data points was comparatively small, to draw a single curve through the data points as in Fig. 26.14. A more detailed investigation of the data points during the development of a new crater debris throw model showed, however, that there is a distinct dependency of the density of crater debris on the angle of the slope of the overburden in the area where the crater is formed. This effect is discussed in Section 26.3. 

Thus, the next step in the evaluation was to establish the relationship between the number of hazardous debris pieces per unit area (the areal density) and the debris mass density. Based on the data sheets of the debris fields (Fig. 26.12), a debris size summation curve was developed for each field. A summary of the curves of all 23 fields is shown in Fig. 26.16. A regression with these data points was made (Fig. 26.17), and a final average distribution of the debris size (mass) versus number of debris pieces—standardized for an area of one m and a debris density of 1 kg per m —was the result. The data were evaluated to see if the distribution of the debris size depended on the distance from the crater or the angle from the tunnel axis, but neither were determined to be of significant influence within the range of interest of this study. 

FIGURE 26.16 Summary of distribution of debris size for all debris fields. 

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