Ground response in seasonal frozen regions under moderate intensity earthquakes

The Seismic Design Code (GB50 011-2010) sets four classifications of sites. At the same time the anti-seismic design is mainly based on the conventional mud, neglecting the impact of the permafrost. The parameters for calculating the response of the seasonal frozen ground are based on qualitative analysis which is lack of measured data. The models lack versatility. In accordance with the analogy of different sites at different depths of frozen soil and permafrost shear-wave velocities, the ground response spectra of seasonal frozen sites under moderate intensity earthquake are calculated. It is suggested that in the first and second class sites, in which the shear-wave velocity are higher and the soil depth are thinner, the peak of winter spectra are higher than thaose in summer. Thus, the response spectra in winter should be analyzed. In the third and fourth class sites, there is no need to calculate the spectra influenced by the permafrost.