The estimation of uniaxial compressive strength conversion factor of trona and interbeds from point load tests and numerical modeling

Öztürk H., Altinpinar M.

JOURNAL OF AFRICAN EARTH SCIENCES, vol.131, pp.71-79, 2017 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 131
  • Publication Date: 2017
  • Doi Number: 10.1016/j.jafrearsci.2017.04.015
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.71-79
  • Keywords: UCS, Point load, Discrete element method (DEM), Particle flow code 2D (PFC2D), Trona (natural soda), BONDED-PARTICLE MODEL, ROCK, INDEX


The point load (PL) test is generally used for estimation of uniaxial compressive strength (UCS) of rocks because of its economic advantages and simplicity in testing. If the PL index of a specimen is known, the UCS can be estimated using conversion factors. Several conversion factors have been proposed by various researchers and they 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, laboratory UCS and field PL tests were carried out on trona and interbeds of volcano-sedimentary rocks. Based on these tests, PL to UCS conversion factors of trona and interbeds are proposed. The tests were modeled.numerically using a distinct element method (DEM) software, particle flow code (PFC), in an attempt to guide researchers having various types of modeling problems (excavation, cavern design, hydraulic fracturing, etc.) of the abovementioned rock types. Average PFC parallel bond contact model micro properties for the trona and interbeds were determined within this study so that future researchers can use them to avoid the rigorous PFC calibration procedure. It was observed that PFC overestimates the tensile strength of the rocks by a factor that ranges from 22 to 106. (C) 2017 Elsevier Ltd. All rights reserved.