Estimation of the uniaxial compressive strength of trona and interburden rocks using the point load test results and numerical modeling


Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Mining Engineering, Turkey

Approval Date: 2016

Student: MEHMET ALTINPINAR

Supervisor: HASAN ÖZTÜRK

Abstract:

Point load (PL) test is used as an index for rock strength classification. It is generally used for estimation of uniaxial compressive strength (UCS) because of its economic advantages and simplicity in testing. If the PL index of a specimen is known, the UCS can be estimated according to some conversion factors. Several conversion factors have been proposed by different researchers and are dependent upon the rock type. In the literature, conversion factors on different sedimentary, igneous and metamorphic rocks can be found, but no study exists on trona. In this study, an extensive literature review was carried out and then laboratory UCS and field PL tests were carried out on trona and interburden rocks. PL to UCS conversion factors of the trona and interburden rocks were proposed. The tests were modeled numerically throughout the rigorous simulations using a code called Particle Flow Code (PFC) based on Discrete Element Modeling (DEM) in an attempt to guide researchers having different kinds of modeling problems (excavation, slope stability etc.) of the abovementioned rock types. A calibration coefficient both for UCS and PL testing between macro and micro properties of PFC was calculated. It was observed that PFC overestimates the tensile strength of the rocks by a factor that ranges from 19 to 750.