Tests of Rock Cores, Machias Study Area, Maine.
Abstract
Laboratory tests were conducted on representative rock core specimens received from six core holes located in Hancock and Washington Counties in Maine. The results of these tests were used to gage the quality and uniformity of the rock to depths of 200 feet below ground surface. The core was petrographically identified as predominantly granite with lesser amounts of rhyolite, basalt, and gabbro. Schmidt hardness, specific gravities, compressional wave velocities, and ultimate uniaxial compressive strengths varied somewhat throughout the area, depending primarily on rock type, texture, and nature and degree of fracturing present, if any. Evaluation of the materials from the Machias study area on a hole-to-hole basis indicates that the porphyritic granite is quite uniform and rather competent, offering good possibilities as a competent hard rock medium. The uniformly medium-grained granite was somewhat more variable, with one specimen from Hole MA-CR-13 (at a depth of 39 feet) and several specimens from Hole MA-CR-20 yielding physical test results typical of incompetent rock. The intact medium-grained granite should offer relatively good possibilities as a competent hard rock medium; the highly fractured, medium-grained granite and that containing weathered fracture surfaces were, however, generally incompetent and therefore unsatisfactory. The rhyolite and the basalt and gabbro must also be considered unsatisfactory, as specimens removed at depths greater than 100 feet from each of these holes exhibited physical characteristics typical of incompetent rock.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1970
- Accession Number
- ADA035364
Entities
People
- Robert W. Crisp