Comparison of the efficiency evaluations of selected excavatability classifications for rock masses


DAĞDELENLER G.

ARABIAN JOURNAL OF GEOSCIENCES, vol.14, no.13, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 13
  • Publication Date: 2021
  • Doi Number: 10.1007/s12517-021-07553-x
  • Title of Journal : ARABIAN JOURNAL OF GEOSCIENCES
  • Keywords: Surface excavation, Excavatability classification, Excavatability charts, GSI-based methods, Prediction performance, STRENGTH, STABILITY, GSI

Abstract

The excavatability of rock masses is an engineering operation of open-pit mines. It is of crucial importance with respect to the selection of suitable and cost-efficient excavation methods and equipments in engineering constructions. Within the study, a summary of the literature regarding the existing surface excavatability assessments was reported at first. Then, it was aimed to compare the efficiencies of the old and recent selected excavatability classification charts. Franklin et al. (1971) and Pettifer and Fookes (1994) discussed the earlier excavatability assessment methods, while GSI-based methods were developed by Tsiambaos and Saroglou (2010) and Dagdelenler et al. (2020). Within the scope, datasets including 73 cases from surface excavations held in Greece and Turkey (12 sites in Turkey and 61 sites in Greece reported by Tsiambaos and Saroglou (2010)) were used. In order to compare the performances of the available datasets in the selected classifications, prediction percentage histograms were drawn and overall prediction performance values were calculated for each of the selected classification. Each of them has a high prediction performance over 80% on the actual excavation methods used at site operation. Finally, the graphical presentation for assessment of excavatability of rock mass proposed by Hoek and Karzulovic (2000) was modified by considering the excavation power index relation proposed by Dagdelenler et al. (2020). In addition to some early excavatability assessment proposals, geological strength index (GSI)-based recent proposals were considered together in terms of efficiency evaluations of excavatability of rock masses. It is clearly seen that GSI is a widely used parameter to define quality of rock mass including both joint pattern and properties of joint surfaces which together improve selection of excavation method.