Creep of Single Rocks on Bedrock
Translational movement of single rocks on bedrock was investigated in both the field and laboratory. The research demonstrated that vibrations from road traffic have no apparent effect on rocks in the field area, that the relative importance of the variables changes from site to site, and that the total annual movement of single blocks can be estimated using dip inclination and azimuth, with dip inclination more important. Thermal-creep rates in the laboratory were directly proportional to the sine of the slope angle, the temperature range, and grain size. In addition, creep velocities were inversely proportional to their respective coefficients of static friction. Herein, the theory of thermal creep is developed independent of Mosley9s early work and indicates that movement occurs under different portions of a block at different stages in a heating and cooling cycle. The analysis of work done during thermal creep shows that oscillatory movement occurs in an “inchworm” fashion, with maximum movement occurring in areas of minimum work. In addition, downslope movement occurs during both heating and cooling of the rocks. Finally, abrasion of rock masses by thermal creep apparently contributes to the mechanical weathering of rock.