Abstract Shaft resistance is the major source of bearing capacity and has a critical effect on settlement of prebored and precast pile (PPP). In this paper, the load-transfer behavior and shaft resistance of steel pipe PPP was observed based on real scale pile loading tests. The main focus was on determining the load transfer mechanism and establishing a framework on shaft behavior of steel pipe PPPs. 10 cases of real scale field loading tests were carried out on the fully instrumented steel pipe PPPs, and the load transfer mechanism was observed based on the obtained load-transfer (t-z) curves along the shaft. In addition, the failure surface along the pile shaft was clarified based on the nine small-scale pile loading test results. By analyzing the load-transfer (t-z) curves, it was shown that steel pipe PPP showed two distinctive types of curves related with two different types of failure characteristics – elasto-perfectly plastic and brittle behavior – along the shaft, and this was validated by using intensive finite element analysis. From this, the shaft behavior of the steel pipe PPP can be classified and can be used in analyzing the shaft behavior along the shaft. Moreover, the range and the lower 95% value of the shaft resistance of the steel pipe PPP will be stated for different types of soil the pile is socketed, which can be used as a guideline of PPP design.

中文翻译：

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基于现场荷载传递曲线和有限元法的钢管预制预制桩轴阻力分析

摘要 竖井阻力是承载力的主要来源，对预钻孔预制桩（PPP）的沉降具有关键影响。在本文中，基于真实比例桩加载试验，观察了钢管 PPP 的荷载传递行为和轴阻力。主要重点是确定载荷传递机制并建立钢管 PPP 轴行为的框架。在全仪表化钢管 PPP 上进行了 10 例真实规模的现场加载试验，并根据获得的沿轴的载荷-传递 (tz) 曲线观察了载荷传递机制。此外，基于九个小型桩加载试验结果，阐明了沿桩轴的破坏面。通过分析负载转移 (tz) 曲线，结果表明，钢管 PPP 显示出两种不同类型的曲线，这些曲线与沿轴的两种不同类型的失效特征（弹性-完美塑性和脆性行为）相关，这通过使用密集的有限元分析得到了验证。由此，可以对钢管PPP的轴行为进行分类，并可以用于分析沿轴的轴行为。此外，针对不同类型的承插桩，规定了钢管PPP的轴阻范围和下限95%值，可作为PPP设计的指导原则。钢管 PPP 的轴行为可以进行分类，可用于分析沿轴的轴行为。此外，针对不同类型的承插桩，规定了钢管PPP的轴阻范围和下限95%值，可作为PPP设计的指导原则。钢管 PPP 的轴行为可以进行分类，可用于分析沿轴的轴行为。此外，针对不同类型的承插桩，规定了钢管PPP的轴阻范围和下限95%值，可作为PPP设计的指导原则。