Fragmentation Processes in Soft Rock
Abstract
An experimental investigation has been undertaken to study the fragmentation of soft and hard rock under conditions of impact by spherical steel projectiles and standard ammunition. Laboratory tests involving the firing of 1/4-inch-diameter steel spheres have been conducted both on the Berkeley campus and at the Naval Weapons Center, China Lake. The velocity range at the first site was from 150 to about 1000 ft/sec, using a compressed gas gun, whereas that at the second location using a powder gun for the sphere ranged from 1100 to 8500 ft/sec. The results of the first year of investigation, comprising all the work performed at China Lake, have been documented in Report DNA 3416Z; in addition, the China Lake performance was published in a separate report NWC TP 5700 (January 1975). The present report concentrates on the activity of the second year of operation. Tests were performed to separately measure the energy contained in the waves generated by the impact in the sample, and special procedures were developed and executed to attempt to determine the surface area associated with cracks produced as the result of the collision. These tests were performed on diorite rather than on shale, since the ejecta formation in the latter was found to be negligible for the range of laboratory impact velocities utilized. Photographic measurements of the ejecta and the determination of the crater topography were continued as in the earlier tests.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1976
- Accession Number
- ADA027502
Entities
People
- Jerome L. Sackman
- Werner Goldsmith
Organizations
- University of California, Berkeley