| Popis: |
Oriented specimens of bituminous coal were obtained from a strip mine near Moberly, Missouri, U.S.A. and were sawed and machined into cubes 1.5 in on the side oriented such that the bedding was parallel to one set of faces. The cubes were loaded to failure parallel to or perpendicular to the bedding in uniaxial compression at room temperature and pressure to determine the effect of a change in moisture content from 3.7 to 12.0% on the stress—strain curves, strength at failure and Young's modulus. The change in moisture content was obtained in protected field specimens by careful soaking. The stress—strain curves show little alteration. However, the increase in moisture content causes a decrease in mean strength from 3234 lb/in 2 to 2840 lb/in 2 for specimens loaded perpendicular to bedding and from 2290 lb/in 2 to 1807 lb/in 2 for specimens loaded parallel to bedding. Similarly, Young's modulus is reduced from 2.39 × 10 5 lb/in 2 to 1.57 × 10 5 lb/in 2 for loading perpendicular to bedding and from 2.22 × 10 5 lb/in 2 to 1.53 × 10 5 lb/in 2 for loading parallel to bedding. |
