Modified point load test determining uniaxial compressive dtrength of intact rock.

Abstract

The point load testing machine has been used to establish certain strength relationships obtained from the results of tests carried out on irregular lump specimens of some Nigerian limestones. The parameters used in the derivations of the relationships include the point load strength index (Is), shape factor (L/D), specimen thickness and the reduction ratio. The methods of rock classification by Deere and Miller and that proposed by Turk and Dearman have been slightly modified for the purpose of rock classification in the field. Based on the intact strength and Rock Mass Rating, the rock mass quality of some limestones from Southern Nigeria have been estimated.