Relationship Between Static and Two Types of Dynamic Moduli for Different Rocks

Modulus of elasticity, used to express the deformability of rocks is very important for the design of structures. This is determined by static and dynamic methods. Present studies were carried out on rock cores with different mineral compositions from four different project sites in different geological set up, to determine dynamic modulus of elasticity with resonance frequency and sonic pulse velocity techniques. Same cores were used to determine static modulus of elasticity with compression method. The rock cores samples of NX size (54 mm diameter) were extracted from bore holes drilled in the foundation area of different sites having rock type of Gneiss, Basalt, Granite and Quartzitic sand stone. Different rocks with variable mineral composition have wide range of moduli values. Statistical interpretation using regression analysis of test results indicated significant correlation between the moduli values determined by different methods. Accordingly one of the methods can be used to determine the moduli of elasticity and other moduli can be determined from correlation factors.