桩筏(箱)基础的荷载分担实测、计算值和机理分析

Load-sharing between pile and raft or box in field experiment, calculation and mechanism analysis

根据国内外 17 幢建筑物的桩筏(箱)荷载分担的大量现场实测资料,以及实用简易计算公式、半理论-半经验反算公式、有限元结合统计的实用计算公式和桩筏(箱)荷载分担计算公式的计算结果,对 20d×20d 的桩筏基础进行共同作用的定性机理分析,并加以综合,论证荷载分担的合理性,特别是计算结果和 8 幢现场实测资料进行比较的结果相当吻合。最后,提出合理可行的具体建议:对于武汉和上海的两种不同地基,筏箱底板分别可承担 15 %～20 %和 5 %～10 %建筑物的荷载,并经公式计算,由工程师结合当地经验和自己的创造性确定,以期能早日列入规范,节省投资。

Based on three aspects: (1) the great deal of data in field experimental study of piled raft or piled box foundations for 17 buildings at home and abroad; (2) calculated results using four methods: simple practical method, semi-theoretical and semi-empirical method, FEM integrated with statistic method and theoretical method; (3) mechanism analysis taking the piled raft foundation with 20 d × 20 d as a model, this paper synthetically demonstrates the reasonableness for loading between pile and raft or box. Especially, the calculated results are satisfactory in agreement with the data obtained from 8 piled raft or box foundations for buildings. Finally, the available suggestions have also been proposed in detail for reference of drawing up a new item in foundation code.