大次数循环荷载下钢管桩承载变形特性试验研究

Experimental study on bearing and deformation characteristics of steel pipe piles under large number of cyclic loading

钢管桩基在海洋服役过程中受到长期循环荷载的作用,研究大次数循环荷载下钢管桩的承载变形特性对海上风电工程的建设有重要意义。本文开展了多组双层土中钢管桩基的模型试验,分析大次数循环荷载下不同循环荷载与静荷载组合对桩基的极限承载力、桩顶沉降、桩身应变的影响。试验结果表明,在大次数循环荷载的作用下,上层淤泥质黏土、下层砂土的双层地基中钢管桩的极限承载力先减小后增大,并趋近稳定;桩顶沉降及其发展速率随着静荷载与循环荷载的增大而增大;循环荷载在桩基利用率中占比越高时,桩基的累积桩顶沉降、桩身应变越大。本文的研究可为钢管桩基在海上风电的应用提供参考。

The steel pipe pile foundation is subjected to long-term cyclic loading during the marine service process.It is of great significance to study the bearing and deformation characteristics of steel pipe piles under large number of cyclic loading for the engineering construction of offshore wind power.In this work,multiple groups of model tests of steel pipe pile in double-layer soil were carried out.The effects of different combinations of cyclic loading and static loading on the ultimate bearing capacity of the pile foundation,pile top settlement and pile strain of steel pile under large number of cyclic loading were analyzed.The test results show that the ultimate bearing capacity of the steel pile first decreases and then increases to an stable value under the large number of cyclic loading in the double-layer soil,whose upper part is mucky clay and the lower layer is sandy soil.Pile top settlement and its development rate increase with the static loading and cyclic loading.The higher proportion of cyclic loading in utilization ratio of pile,the greater the pile top settlement and the pile strain.The experimental results can provide reference for the application of steel pipe pile foundation in offshore wind power.