Accession Number:

ADA091370

Title:

Laboratory Study of Deep-Based Structures in Support of DIABLO HAWK.

Descriptive Note:

Final rept. 15 Sep-31 Dec 77,

Corporate Author:

SRI INTERNATIONAL MENLO PARK CA

Personal Author(s):

Report Date:

1978-02-01

Pagination or Media Count:

135.0

Abstract:

Laboratory studies were performed in support of DIABLO HAWK structures and cable-hardening experiments to investigate 1 the influence of loading rate on tunnel closure in both water-saturated and dry specimens of SRI RMG 2C2, a tuff simulant 2 borehole collapse mechanisms and boreholecable interaction and 3 the influence of joints and joint orientation on the closure of circular tunnels in specimens of jointed 16A rock simulant. Results for SRI RMG 2C2 show that greater pressure must be applied in dynamic tests than in static tests to achieve a given tunnel closure. The percentage increase in pressure is twice as large for saturated specimens than for dry specimens. This larger loading rate effect in saturated specimens is due, in part, to no porewater migration and drainage in the dynamic tests. Static and dynamic borehole collapse and boreholecable interaction test results show that springline collapse is the dominant borehole closure mechanism and that the most severe loading on the cable is from the inward motion of springline rubble. Observed critical loads for cable damage suggest that the TRW fielding ranges in DIABLO HAWK should provide the desired range of damage from none to severe.

Subject Categories:

  • Electrical and Electronic Equipment
  • Civil Engineering
  • Armor

Distribution Statement:

APPROVED FOR PUBLIC RELEASE