土層設計參數不確定性之量化分析－－以員林地區為例

A Quantitative Analysis of Uncertainty in the Design Soil Parameters - A Case Study of the Yuanlin Area

本文以彰化縣員林鎮之現地SPT 及CPT 試驗資料為研究案例，利用地質統計方法建立研究區土層性質的空間結構，並求得土層設計參數的不確定。本文結果獲得研究區域SPT-N 、FC 、Wt 、CPT-qc 及CPT-fs 之空間結構，其水平向關連距離分別為1160m 、750m 、342m 、500m 及43m ，垂直向分別為9.1m 、5m 、4.25m 、6m 及3.15m ，顯示土層垂直向變異高於水平向變異；而SPT-N 、FC 、Wt 、CPT-qc 及CPT-fs 之偏差係數分別為17% 、24% 、2% 、6% 及17% 。

In this paper, the in-situ data of the standard penetration test and cone penetration test in Yuanlin, Changhua are taken as case studies. The geostatistics method is used to build the spatial structures of soil parameters including SPT blow count (N), fines content (FC), saturated soil unit weight (Wt ), cone tip resistance (qc ) and sleeve friction (fs ), and to determine the variability of design soil parameters. The analytical results show that the horizontal correlation distances in N, FC, Wt , qc and fs are 1160 meters, 750 meters, 342 meters, 500 meters and 43 meters, respectively. A nd the vertical correlation distances in the parameters are 9.1 meters, 5 meters, 4.25 meters, 6 meters and 3.15 meters, respectively, which indicates the vertical variability is higher than the horizontal variability. The coefficient of variability in N, FC, Wt , qc and fs are 17%, 24%, 2%, 6% and 17% in turn.