四川地区深度小于30m钻孔的估计方法

本文收集了733个四川地区的实测钻孔数据,从中筛选出深度大于30m的268个钻孔剖面资料。分别获得了10m、15m、20m、25m和28m不同深度处的平均剪切波速 与 的对数线性相关关系。同时还与Boore（2004）的结果做了对比分析,比较了采用常数外推法和对数线性外推法得到的不同深度处剪切波速的残差分布。结果表明,不同深度处剪切波速 与 的对数相关关系可能具有一定的区域性特征,本文得到的对数关系更适合四川地区。对数线性外推法与常数外推法相比,前者的系统偏差更小;随着深度的增加,两种方法的外推误差均逐渐减小,但常数外推法普遍低估了 值;当深度较浅时,低估的情况更为明显。本文的研究结果为利用大量的不足30m的钻孔资料估计 值提供了参考。

Estimation Method of for Drilling with Depth Less than 30 Meters in Sichuan Area

In this paper, we collected 733 borehole data with real measurement value from the area of Sichuan province, and screened out profile information of 268 borehole data with depths more than 30m. Through statistical analysis, we obtained the log linear relationship, in which average shear wave velocity correlating with the at different depth (d=10, 15, 20, 25, 28m). We also compared our relationship with the results of Boore (2004). Finally, we compared the log residual distribution of extrapolation value constant extrapolation with log linear extrapolation at different depth. The results indicate that the log linear relationship is of some regional features, perhaps is more suitable for Sichuan area. Compared with the constant extrapolation, the system error of log extrapolation is significantly small. And with increase of depth, extrapolation results of two kinds of method are gradually close to the real measurement value, but the constant extrapolation will usually underestimate the value of , especially at shallow depth. Our results in this paper improve the reference for using the huge number borehole data with depth less than 30m to estimate value.