Selection of proper specimen size for indentation test in rocks

الملخص EN

The paper describes the indentation test (one of the indirect tensile test) on a squared face specimens of Doloraitic limestone taken from Te-lafer area at the north-west of Iraq.

The stress distribution across the specimen central vertical plane was determined from a linear elastic finite element analysis, and the proper indenter width was determined theoretically.

The effect of the specimen face side (a), and the effect of the thickness of face side ratio (t/a) on the tensile strength of rock were studied experimentally.

These are done by performed the indentation tests on a rock specimens having a ration (t/a) of 0.2, 0.3, 0.4, 0.6, 0.8 and 1.0 with a specimen face side (a) of 4cm, 8cm, 12cm, and 15cm.

Finally the ratio of specimen thickness to its face side (t/a) as well as the specimen size (specimen dimensions) are recommended for the indentation test.