Browsing by Author "Schilizzi, Paul P. G."
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- Monitoring and prediction of surface movements above underground mines in the eastern U.S. coalfieldsSchilizzi, Paul P. G. (Virginia Polytechnic Institute and State University, 1987)The increased impact on mine subsidence during the recent years led to the development of two semi-empirical prediction methods for the eastern United States coalfields. The methods are based on an extensive data bank, which includes a total of twenty three panels, from nine case studies, which were instrumented during this research effort. An extensive field monitoring program, utilizing a digital computer tacheometer, was developed and implemented for this purpose. The first prediction method using a profile function, provides a fast and convenient method for prediction of vertical movements above mine panels of uniform geometry. More specifically the hyperbolic tangent function is utilized, as adapted to regional data. The developed model is capable of accurate general predictions for the Eastem U.S. coalfields. The second method is based on the Budryk-Knothe influence function. The parameters used in this method were mainly determined from the monitored case studies. The use of such a method requires primarily a computer, however, it can negotiate mine sections of complex conditions and can calculate subsidence as well as any other mode of deformation on the surface. For the prediction of the parameters required for the application of both methods a number of relationships between mining and subsidence factors were established through the analysis of the collected data. Computer software were developed for the analysis of the data as well as for the application of the prediction methods.
- The potential of sonic wave propagation in engineering rock classificationSchilizzi, Paul P. G. (Virginia Polytechnic Institute and State University, 1982)Sonic wave methods can be used to provide information on the engineering properties of rocks. The advantages of such techniques include minimal sample preparation, fast site preparation for field tests, reproducible and nondestructive tests, and capability for large scale testing. During this research an extensive review of the most widely accepted engineering rock classification systems was undertaken and their principles, advantages and disadvantages are presented in detail. The mathematical equations describing wave propagation through elastic and viscoelastic media are analyzed in order to determine the dynamic parameters most likely related to static properties. A detailed description of the instrumentation and experimental procedures used for sonic testing is presented. Based on the experimental data, a correlation between the most characteristic static and dynamic properties was established. These relationships can be used to modify existing engineering rock classification systems, by appropriately substituting static properties by the much easier to measure, in the field and in the laboratory, sonic wave parameters. Furthermore, a classification scheme was developed, incorporating information pertaining to the static modulus of elasticity and frequency of joints from sonic wave information.