Edge load strength test for indirect estimation of unconfined compressive strength

Abstract In this paper a new test called “Edge Load Strength” (ELS) for indirect estimation of unconfined compressive strength (UCS) of rock samples is introduced. The test apparatus is almost the same as point load test apparatus except that a flat seating replaces the lower conical platen of the point load apparatus. A cubic rock sample is placed on this seating and the point load is applied by the upper conical platen at a certain point close to the edge of the sample. The applied loads and the vertical displacements are continuously recorded during loading. The failure surface passes through the point of application of the point load by the upper conical platen and the front face of the specimen. ELS is carried out on 10 rock types and the results are correlated with the results obtained from UCS tests. It is shown that rather good correlations exist between ELS and UCS tests for the estimation of rock strength and elastic modulus.

[1]  Akshay Venkatesh,et al.  Correlation Between Point Load Index and Uniaxial Compressive Strength for Different Rock Types , 2012, Rock Mechanics and Rock Engineering.

[2]  I. Forster,et al.  The influence of core sample geometry on the axial point-load test , 1983 .

[3]  Massoud Palassi.  Axially confined point load testing , 2011 .

[4]  Hardy J. Smith.  The point load test for weak rock in dredging applications , 1997 .

[5]  E. T. Brown,et al.  Underground excavations in rock , 1980 .

[6]  Z. T. Bieniawski,et al.  Suggested methods for determining the uniaxial compressive strength and deformability of rock materials: Part 1. Suggested method for determination of the uniaxial compressive strength of rock materials , 1979 .

[7]  Z. T. Bieniawski,et al.  The point-load test in geotechnical practice , 1975 .

[8]  P. Grasso,et al.  Problems and promises of index testing of rocks , 1992 .

[9]  J. A. Franklin,et al.  THE POINT-LOAD STRENGTH TEST , 1972 .

[10]  Adnan Aydin,et al.  Predicting Uniaxial Compressive Strength by Point Load Test: Significance of Cone Penetration , 2006 .

[11]  K. T. Chau,et al.  Uniaxial compressive strength and point load strength of rocks , 1996 .

[12]  S. Kahraman.  Evaluation of simple methods for assessing the uniaxial compressive strength of rock , 2001 .

[13]  T Szwedzicki,et al.  Indentation hardness testing of rock , 1998 .

[14]  G. Tsiambaos,et al.  Considerations on strength of intact sedimentary rocks , 2004 .

[15]  S. Kahraman,et al.  A Comparative Evaluation of Indirect Methods to Estimate the Compressive Strength of Rocks , 2005 .

[16]  M. Heidari,et al.  Predicting the Uniaxial Compressive and Tensile Strengths of Gypsum Rock by Point Load Testing , 2012, Rock Mechanics and Rock Engineering.

[17]  D. K. Ghosh,et al.  Point-load strength: An index for classification of rock material , 1991 .