基于自平衡法后压浆灌注桩荷载传递函数的变化分析

Analysis on the load transfer function of post-grouting bored pile based on self-balanced method

通过对实际工程自平衡试桩资料的分析,根据自平衡试桩的特点提出上下段桩选取不同荷载传递函数模型及压浆前后采用不同荷载传递函数模型,并采用Mindlin位移解与荷载传递法混合求解来考虑土体连续性的影响进行承载特性分析,最后通过一个工程实例验证了该模型的合理性。结果表明,荷载传递函数模型选取是正确合理的,考虑压浆后桩的荷载传递函数模型的变化影响更符合实际工程;土体连续性对超长桩的承载力及沉降计算有着较大影响,考虑土体连续性的桩顶位移比未考虑土体连续性的要大,结果偏安全。

Based on the data analysis of self-balanced pile testing in the actual projects, this work presents different load transfer function models for upper and lower pile sections before and after grouting according to characteristics of self- balanced testing technology. Furthermore, the Mindlin displacement solution mixed with load transfer method is used to consider the influence of soil continuity and analyze the bearing characteristics. Finally, a case study is performed to demonstrate the validity of the proposed models. The results indicate that these proposed load transfer function models are correct and reasonable, and the model of post-grouting pile is more consistent with the actual engineering. Moreover, the comparison also implies that the soil continuity of super-long pile has a significant influence on bearing capacity and settlement. Compared with the case of ignoring soil continuity, the displacement of pile head will be larger and safer when considering the soil continuity effect.