Excavations in Frozen Ground. Critical Depth Shots (100 and 500 Lb) in Fort Churchill Till

摘要

Tests were conducted from February to March 1956 at Fort Churchill (Canada) to determine if the critical depth curve obtained earlier for small charges (0.5-20 lb) could be extrapolated for larger charges. The results, based on firings of three 100-lb and four 500-lb charges of Atlas 60% gelatin dynamite, indicate that the definition for critical depth must be revised for the larger charges if the extrapolation is to be valid.