Constitutive Relations of Coal and Coal Measure Rocks. Volume III Drying Shrinkage and Creep Behavior of Coal.
NTIS: PB/83-178269 :114 pages
Uniaxial testing was performed on coal specimens to determine the time-dependent response. The testing was carried out on coal from six mine sites throughout the western United States and Pennsylvania. Testing configurations were varied to allow analysis of moisture dependency, stress level, and specimen orientation. Several theories were presented for the behavior of coal due to moisture diffusion. Experimental results showed the correlation between the theories and the actual material response. Coal deformation was found to be highly dependent on the mositure level of the testing environment. Moisture migration causes drying and shrinkage which lead to progressive degradation of the material. The coal tested experienced a rebound if saturated after a period of drying. This type of time-dependent behavior overshadows a noticeable creep behavior. Analysis of one series of creep test results was performed. A relationship was developed on the basis of a simplified rheological model to describe the coal response to uniaxial stress.
CP; Final Contract Report;
NTIS Accession No.
University of Colorado