Date of Graduation
Statler College of Engineering and Mineral Resources
Felicia F. Peng
A major aspect of coal mine design is the structural stability of the mine. For establishing structural stability, the strength of the strata is determined by recovering the cores. The strength is determined through various methods and one method in particular is the Uniaxial Compressive Strength of the rock, which is commonly adopted as the standard strength indicator. However, in-situ behavior by past researchers have shown that rock and coal show significant residual strength contrary to the failure path observed in a conventional compression tests. Researchers in past had used stiff system for generating the post failure behavior of the rock and the results produced from these tests were applied to tunneling and hard rock mining. In addition, with the advent of computing system, geotechnical software is extensively used for mine stability analysis. They require correct inputs for producing practical and meaningful results. An extensive amount of literature is available in tunneling and hard rock mining, however, there is a dearth of literature in coal and coal measure rocks on post-failure behaviors. In addition, limited information is available on the proper method to be employed for understanding such behavior.;This thesis seeks to address this issue by performing various tests on rock and coal samples obtained from mines in West Virginia, Utah and sandstone quarries in Tennessee. Six different types of rocks (Berea sandstone, medium-grained sandstone, and coarse-grained sandstone, massive sandstone with coal streaks, grey shale and black shale) were tested in the rock mechanics laboratory. Two feedback-control modes: axial strain control and lateral strain control modes was adopted to study the post-failure behaviors of those samples. Load control was used for comparing the results with the other adopted methods. Results from these experiments show that using axial strain control and lateral strain control, the complete pre and post failure curve can be suitably obtained which are similar to the in-situ rock and coal behavior. In addition to the above finding, a possible mechanism of coal bump is also proposed which, will advance further experimental work in this area.
Nie, Dachao Neil, "Experimental analysis of the post-failure behavior of coal and rock under laboratory compression tests" (2011). Graduate Theses, Dissertations, and Problem Reports. 281.