关键词: 桩筏基础, 位移场, 工作机理, DIC, 破坏模式

Abstract:

In order to study displacement field characteristics and working mechanism of pile raft foundation, a displacement analysis procedure is worked out based on digital image correlation (DIC) method. This procedure is used to study a series of images captured from the model test on pile raft foundation; the whole gradual deformation process of soil around piles is got from this analysis; the failure pattern of pile foundation is also deduced. The study results show that it is viable to analyze the displacement field around piles by the procedure of DIC; and a full displacement field is got from this analysis. Small pile spacing will weaken the single pile bearing capacity. The compressive region is mainly centralized in the soil beneath the pile tip to the pile raft foundation with 3b spacing, which presents a massive deep foundation failure pattern. But to the pile raft foundation with 6b spacing, the compressive region is mainly on the upper part of pile which is about 1/3 of pile length; the displacement influence length evidently smaller than the pile raft foundation with 3b spacing; and it is destroyed by the lateral squeeze of the soil around piles.

Key words: pile raft foundation, displacement field, working mechanism, digital image correlation, failure pattern