Geotechnical Descriptions of Rock and Rock Masses.
Abstract
Geotechnical descriptors for rock and rock mass are suggested for use in the field that can be readily understood by geotechnical engineers and contractors. Geotechnical applications include tunnel support. slope and foundation stability, and rock excavation. The descriptors are rock type, strength, discontinuity characterization, weathering, rock quality designation (RQD), ground-water conditions, and rock density. The rock name or type should be retained in field description but uncommon rock names should be accompanied by a brief definition to enable the user to relate to more common rock types. Rock strength should be described quantitatively by the point load index test. Descriptions of discontinuities should include measurement and classification of aperture and a determination of whether the discontinuity is open or tight; filling thickness and composition; wall asperity or roughness; and orientation of individual discontinuities; sets and systems. Use of stereographic projection and unambiguous azimuthal notation to describe discontinuity orientation is recommended. Bieniawski's classification of rock weathering is recommended. Field recognition and description of seepage and groundwater conditions along discontinuities based on simple observations of the amount of water present and estimates of discharge are recommended to precede and augment the design of more elaborate pore pressure and seepage analysis investigations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1985
- Accession Number
- ADA157493
Entities
People
- W. L. Murphy