EFFECT OF 1D VERTICAL VARIABILITY OF SHEAR MODULUS ON THE SEISMIC RESPONSE OF SITES

Urban development is increased and the construction of building on poor quality soils becomes non avoidable which increases the geotechnical risk. Below these circumstances, the probabilistic approaches to study the behavior of a soil profile in a given environment have been proposed in recent years. The purpose of this research work is to study the effect of vertical variability of soil shear modulus on soil seismic response using the probabilistic approach. Two types of heterogeneity are considered: (1) heterogeneity due to the random distribution of the shear modulus in a soil profile; (2) heterogeneity of soil layer with shear modulus increasing linearly with depth. The first heterogeneous soil models are generated by Monte Carlo simulation. The spatial variation of the shear modulus is controlled by the variation coefficient parameters. The second heterogeneous soil models are assumed to have shear modulus increasing linearly with depth. These heterogeneous soils are generated and then integrated into the computer program based on the one dimensional wave propagation, resulting in seismic responses at the 'free field' soil. To demonstrate and show the importance of considering heterogeneities in the model, the results are compared with examples of deterministic analysis by means of the experimental value of shear modulus obtained from a specific site in Algeria.