EARTH DISPLACEMENT (SHEAR SHAFTS).
DEFENSE ATOMIC SUPPORT AGENCY WASHINGTON D C
Pagination or Media Count:
No significant permanent movement, either vertically or radially, was observed for any of the shafts in the surface shot area. In the underground shot area, definite and significant movements were observed only for the two innermost shafts at 250 and 312 on the main south blast line, each shaft being dis placed radially outward less than a foot at the ground surface. Vertical movements of the tops of the shafts at these same locations were considerable less and of the order ff 0.75 to 1.5 inches downward. The horizontal and ver tical movements observed were due principally to rotation at translation of the top five foot segment of pipe and should not be inter preted as applicable to the entire shaft as a unit. For the conditions and locations in effect in these tests, it appears that major permanent displacements will not extend beyond approximately two and three lambda for surface and shallow underground shots, respectively, except for possible local disturbances very near the ground surface. There is considerable asymmetry in permanent displacements about ground zero in the underground tests. Author