2. Dynamic soil behavior

2.1 Shear modulus G and shear strain amplitude

Deformation moduli depend on the amplitude of deformation. The orders of magnitude of deformations for structures are on average between 10 ^-4 and 10 ^-2 whereas conventional tests (penetrometer, oedometer, conventional triaxial) give moduli representative of deformations in excess of 10 ^-2 .

For the design of structures under the action of an earthquake, knowledge of the shear modulus G in the deformation range 10 ^-4 and 10 ^-6 is required, as is the damping ξ.