RFP桩复合地基受力特征现场试验及数值模拟

Field Experiments and Numerical Simulation of Bearing Characteristics of RFP Composite Foundation

为研究刚–柔性桩(RFP)复合地基的受力特征,分析了青岛某高层建筑RFP复合地基载荷试验过程中及建筑物建设过程中取得的实测资料,并运用有限差分法模拟了不同厚度褥垫层的RFP复合地基分级加载过程,研究结果表明:加荷初期,由于褥垫层的压密及刺入调整作用,刚性桩、柔性桩和桩间土荷载均增长较快;随着荷载增加,桩间土和柔性桩所承担荷载增加缓慢,荷载增加值主要由刚性桩承担;褥垫层厚度的增加对荷载的分担改善作用明显,可有效改善桩土应力比,RFP复合地基褥垫层宜取200~300 mm。

In order to study the bearing characteristics of the rigid-flexible pile(RFP)composite foundation,the engineering testing data obtained from the bearing tests and construction process of a high-rise building with such foundation in Qingdao were analyzed,and the finite difference method was applied in simulating multi-stage loading process of rigid-flexible composite foundation with the cushion layer of different thickness.Study results show that at the beginning of the loading stage,due to the compaction of cushion layer and the effect of penetration adjustment,loads on rigid pile,flexible pile and inter-pile soil increased very rapidly;with the increasing of loads,the load increment on inter-pile soil and the flexible pile grew very slowly and the increment was mainly born by the rigid pile;The increase of the cushion layer thickness has an obvious effect on the load sharing,and it can effectively improve the stress ratio of piles and soils.The cushion of the RFP composite foundation is suitable for 200~300 mm.