INVESTIGATION AND REPAIR OF TECTONIC AND STORM-RELATED ROAD DAMAGE NEAR THE GARLOCK FAULT, CALIFORNIA

The article examines the occurrence of major damage to the Randsburg Wash Test Range access road at the Naval Weapons Center duuing a thunderstorm on August 18, 1983. The damage occurred within zones of weakness related to tectonic strain accumulation across thee nearby Garlock fault. Two zones of 4.5 m of compacted decomposed granite. (TRRL) 686 m long, intersect the road. The primary damage, largely erosional, included open fissures up to 30 cm wide, and open and collapsed tunnels with cross-sectional dimensions of 1 to 2 m. Repair of the road involved four major considerations: (1) open fissures extending to an unknown depth, (2) continuing tectonic strain accumulation, (3) localized heavy rainfull and flash flooding, and (4) maintaining the road in a safe and usable condition. These considerations required the incorporation of somewhat novel, non-standard repair techniques which involved extensive exploratory excavation and engineered backfilling. About 900 cu m of material were excavated to an average depth of 4 m. The stratigraphy included up to 0.7 m of unconsolidated silty sand underlain by 3 m of plastic lacustrine clay and an unknown thickness of course, unconsolidated, uniformly graded sand. These materials were replaced by engineered fills designed to: prevent erosion of the subgrade; bridge or collapse into cracks or fissures that may develop; prevent or diminish the effects of reflection cracking; allow drainage; and accommodate tectonic strain. The road-shoulder backfill consisted of 1.5 m of a compacted mixture of arkose and the previously excavated clay overlain by 3.5 m of compacted arkose. The road backfill included a basal, 0.5-m-thick layer of cobbles, an overlying 0.5-m-thick layer of compacted, 19 mm concrete aggregate and 4.5 m of compacted decomposed granite.

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  • Supplemental Notes:
    • Recent Advances in Bus Transit Operations Planning.
  • Corporate Authors:

    Association of Engineering Geologists

    P.O. Box 506
    Short Hills, NJ  United States  07078
  • Authors:
    • Zellmer, J T
    • Roquemore, G R
    • Pannuto, B J
  • Publication Date: 1984-11

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Filing Info

  • Accession Number: 00396204
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jan 31 1986 12:00AM