Study on Seismic Waves’ Speed Changes under Different Conditions and Determination of Soil Parameters by Using Them

The measurement of seismic waves speed, particularly shear waves, takes a key and determinative role in classification of land type, carrying out special site studies in terms of earthquake risk and dynamic design of underground structures. The speed of shear wave in soil layers is one of the fundamental components in geotechnical calculations and dynamic analyses, particularly determination of dynamic shear module, elastic module, hardness level, Poisson’s ratio, soil bearing capacity and so on. In view of wave speed changes in different formations of land, which is a function of kind, density, porousness, water content and elastic qualities of those formations, this paper first studies the amount of speed changes of seismic waves in different environments and different conditions of soil. The results of studies indicate that waves speed has considerable changes in different conditions. Then, the required parameters which can be determined through the speed of shear and longitudinal waves such as elastic module, shear module, poisson’s ratio, foundation bearing capacity, bed reaction coefficient, soil unit weight, etc., have been studied.

کلیدواژه ها:

shear wave ، longitudinal wave ، seismic waves speed ، soil parameters