Rock Mechanics and Rock Engineering

, Volume 45, Issue 6, pp 1131–1135 | Cite as

Reply to Discussion by Li and Wong on “Predicting the Uniaxial Compressive and Tensile Strengths of Gypsum Rock by Point Load Testing” by Heidari et al., Rock Mechanics and Rock Engineering (2012) 45:265–273

  • M. HeidariEmail author
  • G. R. Khanlari
  • M. Torabi-Kaveh

Specimen and Sample

It is clearly stated in the paper that 40 block samples from gypsum rock were collected and cored. Then 90 cores (perpendicular to stratification) and irregular specimens were prepared from gypsum rock for point load tests (PLT) (for different types of PLT in both air-dried and saturated states). Also 60 cores were prepared for UCS and Brazilian tests (in air-dried and saturated states). 15 specimens (in the paper, “specimen” and “sample” have the same meaning) were numbered randomly from G 1 to G 15 for each test. It seems that Li and Wong assumed the number presented in each row of Tables  1 and 2 to have been obtained from the same rock block. In other words, different core samples were prepared from different blocks of gypsum rock.
Table 1

Equations correlating the UCS to the point load index Is(50)


Correlating equations

D’Andrea et al. (1964)

UCS = 15.3 Is(50) + 16.3

Deere and Miller (1966)

UCS = 20.7 Is(50) + 29.6

Singh (1981)

UCS = 18.7 Is(50) − 13.2



Conversion Factor Uniaxial Compressive Strength Rock Specimen Weak Rock Brazilian Test 
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The authors gratefully acknowledge the discussers for their interest in the paper and their effort to provide the community with detailed and constructive comments.


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Department of Geology, Faculty of SciencesBu-Ali Sina UniversityHamedanIran

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