Relationship between Shear Wave Velocity and Buried Depth in Tianjin Plain Area

YI Wenxing; LI An; LEI Shengxue; GUO Changhui; YUAN Haodong

doi:10.13512/j.hndz.2024.01.06

Abstract：Tianjin is located in the Bohai bay area,and its soil layer is dominated by fine particles,which is prone to seismic and geological problems of foundation failure and uneven settlement.The relationship between shear wave velocity and soil depth is qualitatively analyzed by using the data of borehole shear wave velocity accumulated in Tianjin plain area.The clay,silt and medium fine sand in different sedimentary regions of Tianjin plain area was statistically regressed by using different function fitting models.The regressive statistical analyses show that there is a significant positive correlation between the shear wave velocity and buried depth in Tianjin and the quadratic polynomial function fitting model is more suitable for the prediction of shear wave velocity in this region.The correlation between the sedimentary characteristics of Quaternary strata and shear wave velocity in Tianjin plain area is obvious,which significantly affects the fitting accuracy of the prediction models.After the reliability test,the results show that the average relative errors of the prediction results which used the fitting model with different soil classification and the fitting model without classification is less than 10%.Furthermore,in the case of unknown soil types,using the fitting model without classification to predict shear wave velocity can obtain reasonable reliability results.