局部桩筏基础的设计与施工

以加拿大多伦多市某工程为例,介绍了在复杂地质条件下采用局部桩筏基础（PPRF）的设计及施工问题;探讨了设计PPRF的决定性因素;在保持PPRF设计的完整性前提下,提出了单位沉降量的准则,并用于筏板和桩的设计;计算了PPRF的滑移及转动;最后,采用有效方法对该工程采用的局部桩筏基础进行了计算分析。结果表明,PPRF的设计主要取决于侧向土压力、分布不均的建筑荷载以及地基土的非均匀承载力,工程桩应主要布置在沉降较大的区域,即位于筏板基础承受高压力而土体承载力较低的西北部。探讨局部桩筏基础的设计与施工为该类型工程的基础设计提供了一个新的解决途径。

Design and Construction of a Partially Piled Raft Foundation

The paper describes the design and construction of a Partially Piled Raft Foundation （PPRF） adopted under complex geotechnical conditions, in the City of Toronto, Canada. The design of PPRF was governed by lateral soil pressure, unevenly distributed building loads, and non-uniform bearing capacity of foundation soils. Piles were distributed in the area with excessive settlement. Most of the supporting piles were located in the northwest portion of the raft foundation, where high hearing pressure and low soil bearing capacity were encountered. A unit criterion of the proposed settlement has been applied in the design of the raft slab and the piles in order to keep the integrity of the PPRF. Global stability, including sliding and over turning of the PPRF were an integral part of the design. A state of the art computer analysis was utilized.