湖北襄阳地区土体剪切波波速与深度的相关性研究

Study on the Correlation between Shear Wave Velocity and Depth of Soil in Xiangyang Area,Hubei Province

为给出湖北襄阳地区典型粘性土、粉土、砂土及碎石土剪切波波速与深度之间的统计公式,基于收集到的102个实测钻孔波速资料,利用多种一元回归模型对襄阳地区常见土层剪切波波速与深度之间的关系进行拟合分析和相关性研究;同时,讨论土体状态对二者关系的影响;最后,利用实测钻孔数据验证统计公式的合理性和可靠性。研究结果表明:1)除人工填土外,襄阳地区其他常规土类剪切波波速与深度之间存在较强的相关性,且离散程度随深度的增加而增大;2)同一土类随密实度或塑性状态的增大,其平均剪切波波速也变大;3)考虑土体状态可以使回归模型的预测结果更加具体、更接近真实值,但对模型拟合优度的变化具有不确定性;4)区域性对土层剪切波波速与深度的统计关系有较大影响。本文研究的襄阳地区各土类剪切波波速回归模型较全国土类模型具有更好的预测精度和误差平稳性,可为南襄盆地及周边区域地震灾害风险普查、场地土动力学性质研究和地震动参数确定等提供参考。

To provide a statistical formula between the shear wave velocity and depth of typical cohesive soil,silt,sandy soil,and gravel soil in Xiangyang area,Hubei Province,based on 102 measured borehole wave velocity data collected in Xiangyang area,we use multiple univariate regression models to fit and analyze the relationship between shear wave velocity and depth of common soil layers.Then,we discuss the influence of soil state on the correlation between the two.Finally,we verify the rationality and reliability of the statistical formula using actual drilling data.The results show that:1)Except for artificial filling,there is a strong correlation between the shear wave velocity and depth of other conventional soil types in Xiangyang area,and the degree of dispersion increases with the increase of depth;2)As the density or plasticity of the same soil type increases,its average shear wave velocity also increases;3)Considering the soil state can make the prediction results of the regression model more specific and closer to the true values,but there is uncertainty in the changes in the goodness of fit of the model;4)Regionality has a significant impact on the statistical relationship between soil shear wave velocity and depth.The shear wave velocity regression models provided in this article for various soil types in the Xiangyang area have better prediction accuracy and error stationarity compared to the national soil type models.They can provide valuable reference basis for seismic disaster risk survey,site soil dynamic properties research,and determination of seismic motion parameters in the Nanxiang basin and surrounding areas.