深厚软基火电厂主要结构桩筏基础设计方法及应用

Design Method for Piled Raft Foundation in Soft Ground and Its Application in Power Plant

桩筏基础因其具有承载力高、沉降小以及调节不均匀沉降能力强等优点而被广泛应用于主厂房、锅炉等电厂重要结构物中。首先介绍了考虑土—桩—筏协调变形的桩筏基础设计方法,该方法主要涉及群桩下卧层附加应力的计算、群桩沉降的确定以及桩筏共同作用分析等方面。与其他桩筏基础分析方法相比,该方法计算群桩中的单桩刚度相对简单准确,可以考虑成层地基、不规则及变厚度筏板、存在相邻基础等复杂情况。对某电厂桩筏基础进行了分析计算,并将计算沉降与实测沉降进行了对比。

Piled raft foundation has been widely used in power plants due to its high compressive capacity, small settlement and strong capacity to adjust differential settlement. This paper introduces a design method for piled raft foundations with consideration of soil-pile-raft interactions. The method focuses on three aspects including calculation of the vertical stress under pile tip, determination of the pile group settlement and integrated analysis of the piled raft foundation. Compared with other methods for piled raft foundation, this method is simpler and more accurate in calculation of the stiffness of single pile in pile groups, and takes into account of complicated conditions, such as layered ground, irregular raft with variable thickness and foundations with adjacent foundations. A case study was carried out on the piled raft foundation of a power plant with the software of POGAP based on above method, and a comparison was made between the calculated results and the measured settlement, which is proved to be in good agreement.