Seismic ground motion analysis of saturated frozen soil free field under P-wave incidence
The amplification or damping of seismic waves is impacted by the characteristics of the site,making it essential to use a precise site model for assessing seismic ground motion.To investigate the seismic ground motion properties of frozen soil sites in the western alpine region,a model is developed.This model is based on the principles of elastic wave propagation in both single-phase elastic media and frozen saturated porous media.Specifically,the model focuses on a free site of saturated frozen soil that is situated above bedrock and is subject-ed to P-wave incidence.By considering the case of plane P-wave incidence,an analytical solution for the seis-mic ground motion of this free site is derived.The seismic ground motion of a saturated frozen soil free site is an-alyzed for plane P-wave at different incidence angles using numerical calculations.The influence of physico-me-chanical parameters,such as incident frequency,porosity,medium temperature,cementation parameter,and contact parameter,on the seismic ground motion is examined.The analytical results indicate that the frequency of plane P waves significantly affects the surface displacement of the free site of saturated frozen soil overlying bedrock.The horizontal displacement of the free site of saturated frozen soil overlying bedrock diminishes as the frequency of the P wave increases,but the vertical displacement of the surface increases with higher frequencies;An increase in porosity leads to an increase in the horizontal displacement of the free surface of saturated frozen soil on bedrock.The magnitude of this increase initially rises and then falls with the increase of the angle of inci-dence of the P-wave.Additionally,vertical displacement also increases,with the magnitude of the increase de-creasing gradually as the angle of incidence increases;Decreasing the temperature of the medium reduces both the horizontal and vertical displacement of the surface of the saturated frozen soil free field on the bedrock,dem-onstrating the significant impact of the ice phase on the propagation of seismic waves in the frozen soil site;Pois-son's ratio affects the displacement of the surface of saturated frozen soil on the bedrock.As Poisson's ratio in-creases,the horizontal displacement of the surface diminishes.As the incident angle of plane P wave rises,the magnitude of this increase initially increases and subsequently declines.An increase in Poisson's ratio leads to a large rise in the vertical displacement of the surface of the free site of saturated frozen soil on the bedrock.The magnitude of this increase diminishes as the incident angle of the plane P-wave increases;An increase in contact parameters leads to a rise in the surface horizontal displacement of saturated frozen soil over bedrock.The ampli-tude of the increase first rises and then progressively diminishes.The vertical displacement of the surface grows while the amplitude of the increase steadily declines.In this paper,extending the fluctuation problem of single-phase elastic solid media,saturated soil media,or unsaturated soil media to frozen soil medium containing ice phases while considering the coupling effect of the phases in frozen soil is exceedingly significant for the study of seismic ground motion characteristics of frozen soil sites in the western alpine region.On the one hand,it can make a theoretical explanation for the ground motion of the earthquakes that have occurred in the western alpine region,and on the other hand,it can make a prediction of the ground motion characteristics of the future earth-quakes that may occur in the frozen soil sites in the alpine region,so as to provide the theoretical basis for the work of seismic small zoning and engineering site selection.In addition,the study of seismic ground motions at frozen soil sites is at the same time a prerequisite for the study of seismic response of large structures and perma-frost structure interaction in the western alpine region.
saturated frozen soilplane P-wavereflection and transmissionground motionanalytical solution
NETL
NSTL
万方数据
