Ramamurthy, T

Realistic Parameters Adoption to Solve Rock Engineering Problems - Vol,48 (4), Dec - New York Springer 2018 - 595-614p.

Strength and modulus of rock mass as obtained from RMR, Q and GSI have been examined with reference to modulus ratio, Mrj, for their reliability. The design parameters adopted in some case studies based on these rock mass classifications are presented. The modulus ratios in these case studies are found to be much higher than those of the corresponding values of intact rocks, even after back analyses. Based on joint factor, Jf, compressive strength, modulus, cohesion and friction angle were estimated and applied in the analyses of a few cases. The predictions of deformations agreed well with the field measurements. Based on extensive experimental data of jointed specimens of rock and rock-like materials, a joint factor, Jf, was defined as a weakness coefficient in rock mass compared to the corresponding intact rock. Jf is linked to the strength, modulus and modulus ratio of rock mass. The modulus ratio, Mrj, of rocks is less than the modulus ratio of intact rock. The Mrj concept has been adopted to present a unified classification for intact rocks and rocks masses, to define soil that rock boundary and penetration rate of TBMs.


Civil Engineering