用于调整差异沉降的预留净空桩筏基础模型试验研究
Piled raft with gap between pile top and raft to adjust differential settlement
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摘要: 预留净空桩筏基础是一种新的利用桩土相互作用的形式,可用于调整建筑物筏板–桩–土相互作用和减少差异沉降。进行了砂土中常规桩筏基础和桩顶预留净空桩筏基础的模型试验研究。分析表明:在相同荷载作用下,在试验条件下,相对于常规桩筏基础来说,预留净空桩筏基础的实质作用在于可使桩间土压缩提前发生,显著提高桩间土分担荷载的比例,在可压密土中可强化桩土相互作用,桩端刺入量显著下降,使得桩土更趋于整体沉降。预留净空桩筏基础可有效利用土的承载力,减小桩顶应力过分集中,且对桩端阻力有显著的强化作用。Abstract: A new type of piled raft was developed with the gap between pile top and raft.It could be adopted to adjust the raft-pile-soil interaction and to reduce differential settlement of buildings.Model tests on piled raft in sand with and without the gap between pile top and raft were carried out.It was shown that the sand among piles with the gap between pile top and raft was compacted earlier than that of coventional piled raft foundation under the same load.The compaction of sand among piles could increase the load carried by soil and at the same time reduce the penetration of pile tip.This would make piles and soil settle together.Piled raft with the gap between pile top and raft could mobilize the bearing capacity of soil effectively,in the meantime reduce the stress concentration at pile top and enhance the bearing resistance of pile tip.