基于灰色模型GM(2,1)的大直径超长桩承载力预测*

基于8根大直径超长桩承载力现场试验资料,选用灰色模型GM(2,1)进行建模和预测,并与两类常用指数模型进行了比较。比较发现,用灰色模型GM(2,1)对8根大直径超长桩承载力进行预测时,相对误差一般为±0.8%;由后验差比值C和小误差概率P共同描述的后验差检验时,灰色模型GM(2,1)的效果为很好;GM(2,1)的预测效果明显好于两类常用指数模型。结果表明,GM(2,1)对样本大小不限,资料的处理可以随时增加更新,保证较高的预报水平;用GM(2,1)预测大直径超长桩承载力是可行的。

Prediction of bearing capacity of large diameter super-length pile based on GM(2,1)

Based on field testing data of 8 large-diameter super-length piles, this paper selected grey model GM(2,1) to predict pile bearing capacity, and carried out a comparison with two types of common exponential models. It was found that the relative error of the predicted value of pile bearing capacity was about±0.8% for 8 large-diameter super-length piles, and the validating effect was very good with the index p and index c; GM(2,1) was better than two types of common exponential models. It is concluded that GM(2,1) is a good model which doesn t limit sample number and can add new sample to assure higher-precision prediction; it is feasible to predict bearing capacity of large- diameter super-length pile based on GM(2,1).