Download - 65fcb4031dffecc8e949e35e83791f64
-
Progress in Physical Geography 30, 6 (2006) pp. 703718
2006 SAGE Publications 10.1177/0309133306071954
I IntroductionThe purpose of this paper is to evaluate thecontribution that the Schmidt Hammer hasmade to geomorphological research. TheSchmidt Hammer (SH) was originally devisedby E. Schmidt in 1948 for carrying out in situ,non-destructive tests on concrete hardness(Day and Goudie, 1977; Day, 1980). The SHhas now been adopted by geomorphologistsfor a variety of reasons, including relative dat-ing, the study of weathering phenomena, andthe effects of rock strength on land forms (eg,Ericson, 2004).
The instrument measures the distance ofrebound of a controlled impact on a rocksurface. There are now several versions of thehammer.
The one most used by geomorphologists isthe N type. It can provide data on a range of rock types from weak to verystrong with compressive strengths thatrange from c. 20 to 250 MPa. A digitalversion, The Digi-Schmidt, is nowavailable, though it is markedly moreexpensive.
The L type hammer has an impact threetimes lower than the N type (0.735 com-pared to 2.207 Nm). It is appropriate forweak rocks and those with thin weatheringcrusts.
The P type is a pendulum hammer fortesting materials of very low hardness,with compressive strengths of less than70 kPa.
The Schmidt Hammer ingeomorphological research
Andrew S. Goudie*St Cross College, University of Oxford, Oxford OX1 3LZ, UK
Abstract: The Schmidt Hammer, originally designed for testing the hardness of concrete in1948, was first used in a geomorphological context in the 1960s. Since then the advantages anddisadvantages of the device for measuring rock characteristics have become apparent, and theSchmidt Hammer has been used for an increasing range of purposes, including the study of variousweathering phenomena, the relationships between rock strength and landform, and for relativedating of a range of Holocene features. Readings of rock hardness have often been found tocorrelate well with other measures of rock character, such as uniaxial compressive strength andYoungs Modulus of Elasticity.
Key words: relative dating, rock strength, Schmidt Hammer, weathering.
*Email: [email protected]
