ISSN - ISRM

14 ISRM (India) JournalFig. 11 : Relationship between Average Young’s modulusand water absorption7.2 Relationship between Fatigue andGeophysical Properties of RockThe relationship between peak fatigue strength and thatwith dry P- and S-wave velocity is shown in Figs. 12 and13, respectively. It is seen that hardly any relation existsbetween these parameters, since the obtained relationcoefficient is very low. The relationship between averageYoung’s modulus and that with dry P- and S-wave velocityis shown in Figs. 14 and 15, respectively. It shows anincrease in average Young’s modulus with an increasein P- or S-wave velocity. Also, the obtained relationcoefficient is at 0.40 and 0.30 in the case of P- and S-wave, respectively, with average Young’s modulus. Fig.16 shows the relationship between average Young’smodulus from dynamic cyclic uniaxial compressionloading under laboratory conditions, and dynamicmodulus obtained from seismic velocity measurement.The plot shows an increasing trend where obtainedrelation coefficient is 0.40. The obtained relationcoefficient in all the above cases is not good statistically,but it shows some trend with different properties. One ofthe reasons of data dispersion in this case is the effect ofrock type or mineralogy variation. As mentioned earlier,the tested rock specimens varied greatly in terms ofmineralogy, texture, structure and sample disturbance,and thus it is hypothesized that dynamic cyclic loadingconditions are very susceptible to rock type in terms ofmineralogy, texture and structure.Fig. 13 : Relationship between peak fatigue strength anddry S-wave velocityFig. 14 : Relationship between average Young’s modulusand dry P-wave velocityFig. 15 : Relationship between average Young’s modulusand dry S-wave velocityFig. 12 : Relationship between peak fatigue strength anddry P-wave velocityFig. 16 : Relationship between average Young’s modulusand dynamic modulus from seismic velocity measurementVolume 1 v No. 1 v January 2012