模型不确定性对砂土中打入桩抗力系数的影响  

Effect of model uncertainty on resistance factor of driven piles in sand

作　　者：原方[1] 李志谦 徐志军[1] YUAN Fang;LI Zhiqian;XU Zhijun(School of Civil Engineering and Architecture, Henan University of Technology, Zhengzhou 450001, China)

机构地区：[1]河南工业大学土木建筑学院,郑州450001

出　　处：《中国科技论文》2021年第10期1040-1045,共6页China Sciencepaper

基　　金：国家自然科学基金资助项目(51608177,51578216)。

摘　　要：为了评价各种砂土中打入桩竖向承载力设计方法的合理性,给出不同设计方法的抗力系数建议值,引入承载力试计比(基桩承载力实测值与计算值的比值)研究模型不确定性。基于高质量的浙江大学-帝国理工学院(Zhejiang University-Imperial College London,ZJU-ICL)子数据库,通过Spearman等级相关性分析,对美国石油协会(American Petroleum Institute,API)和4种基于静力触探(cone penetration test,CPT)的砂土中打入桩设计方法(UWA-05、ICP-05、Fugro-05和NGI-05)的试计比进行随机性验证和数理统计分析,并分别采用一次二阶矩法和蒙特卡洛模拟法计算承载力极限状态下的抗力系数。结果表明:从试计比统计结果来看,UWA-05和ICP-05设计方法的变异系数较小,说明这2种方法较为合理;从抗力系数计算结果来看,UWA-05和ICP-05设计方法的抗力系数较大,API和NGI-05设计方法的抗力系数居中,Fugro-05设计方法的抗力系数较小;ICP-05设计方法的抗力系数与试计比均值的比值最高,经济性最高。To evaluate the rationality of design methods of axial ultimate bearing capacity for driven piles in sand and offer recommended values of resistance factors,a model factor,the ratio of measured resistance to calculated resistance,was introduced to characterize the model uncertainty.Based on Zhejiang University-Imperial College London(ZJU-ICL)database of high quality,the model factors of American Petroleum Institute(API)method and four design methods based on the cone penetration test(CPT)for driven piles in sand(UWA-05,ICP-05,Fugro-05 and NGI-05)were assessed by Spearman rank correlation analyses to verify the randomness.Statistics analyses were applied to the model factors.The resistance factors at ultimate limit state were calculated by the first-order second-moment method and the Monte Carlo simulation method.The results show that according to the statistics of models factors,the coefficients of variation of UWA-05 and ICP-05 methods are relatively low,which indicates these two methods are relatively rational;according to the calculation results of resistance factors,the resistance factors of UWA-05 and ICP-05 are relatively high,and the resistance factors of API and NGI-05 methods are in the middle and the resistance factors of Fugro-05 method is relatively low;The ratio of resistance factor to the mean of the model factor for ICP-05 method is the highest,which indicates ICP-05 method is the most economical.

关 键 词：打入桩 砂土 试计比 模型不确定性 抗力系数 

分 类 号：TU473[建筑科学—结构工程]