Comparative study of seismic ground responses using deepsoil, shake, and d-mod for soils of Goa, India

Abstract

Seismic ground response analysis (GRA) is carried out to quantify the effects of the local soil strata overlying the bedrock on the characteristics of the bedrock motion. In the present study, the variability in the seismic ground response is studied for various input parameters such as soil geometry, use of different shear modulus and damping curves, and methods of analysis by using three software programs, that is, DEEPSOIL, SHAKE, and D-MOD. The study is carried out for a typical soil site located in Goa, India. Considerable differences are found in the output parameters, such as amplification ratio, surface acceleration, peak spectral acceleration, and the frequency content of the response spectrum using various input parameters. It is found that the soil model defined with more number of layers gives a better estimate of the ground response. The mean spectral values obtained by equivalent linear analysis are found to be higher than that of the nonlinear analysis. Nonlinear ground response analysis is recommended as it represents the actual nonlinear soil behavior and the software considered allow for its easy adoption.