ORIGINAL PAPER A correlation between P-wave velocity, impact strength index, slake durability index and uniaxial compressive strength P. K. Sharma Æ T. N. Singh Received: 10 February 2007 / Accepted: 14 July 2007 / Published online: 5 October 2007 Ó Springer-Verlag 2007 Abstract Impact strength index, slake durability index and uniaxial compressive strength (UCS) are important properties of a rock mass which are used widely in geo- logical and geotechnical engineering. In this study, the mechanical properties of one igneous, three sedimentary and three metamorphic rock types were determined in the laboratory and correlated with P-wave velocity. Empirical equations have been developed to predict the impact strength index, slake durability index and UCS from P-wave velocity, which may avoid the necessity for time- consuming and tedious laboratory testing. To check the sensitivity of the empirical relations, a t test was performed which confirmed the validity of the proposed correlations. Keywords Impact strength index  P-wave velocity  Slake durability index  t test  Uniaxial compressive strength Re ´sume ´ L’indice de durete, l’indlce d’alterabilite et la resistance a la compression simple sont des proprietes importantes d’une roche, largement utilisees en geologie de l’ingenieur et en geotechnique. Dans cette etude, les pro- prietes mecaniques d’une roche magmatique, de trois roches sedimentaires et d’une roche metamorphique ont ete determinees au laboratoire et correlees avec les vitesses des ondes P. Des equations empiriques ont ete etablies pour obtenir l’indice de durete, l’indice d’alterabilite et la resistance a la compression simple a partir de la vitesse des ondes P, ce qui permet d’eviter de realiser des essais de laboratoire consommateurs de temps. Afin de verifier la sensibilite des relations empiriques etablies, Ie test t de Student a ete mis en ceuvre et a permis de confirmer la validite des correlations proposees. Mots cle ´s Impact grosseur indice  P-brandir velocite  Slake durabilite indice  t test  Une-axial compressive grosseur Introduction Seismic techniques are often employed to determine and characterize the dynamic properties of rocks. As these techniques are non-destructive and relatively easy to apply, they are increasingly being used in geological and geo- technical engineering. Attempts have been made to assess grouting, rock bolt reinforcement and blasting efficiencies in the rock mass by the seismic velocity (Knill 1970; Price et al. 1970; Young et al. 1985). The prediction of rock mass deformation and stress as well as the extent of damage zones (EDZ) developed around underground openings are other applications of the seismic techniques (Onodera 1963; Hudson et al. 1980; Gladwin 1982). Various researchers have found that sound velocity is closely related to rock properties (Deere and Miller 1966; D’Andrea et al. 1965; Saito et al. 1974; Gardner et al. 1974; Youash 1970; Lama et al. 1978; Inoue and Ohomi 1981; Gaviglio 1989). There are a number of factors that influence the P-wave velocity in rocks including lithology, density, shape and size, porosity, anisotropy, pore water, confining pressure, temperature as well as the properties of the rock as a mass, P. K. Sharma (&)  T. N. Singh Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India e-mail: pks12pes@iitb.ac.in T. N. Singh e-mail: tnsingh@iitb.ac.in 123 Bull Eng Geol Environ (2008) 67:17–22 DOI 10.1007/s10064-007-0109-y