【摘要】 针对桩顶与筏板之间不同构造形式下的相互作用,对可压密土中刚性桩复合地基、常规桩筏基础和桩顶预留净空桩筏基础进行了现场模型试验,测量了筏板沉降、筏板内外不同深度地基土沉降、桩身轴力和桩间土反力,分析了不同荷载级别下筏板沉降、筏板内外不同深度地基土沉降、桩土荷载传递特性和桩土荷载分担比分布规律。与刚性桩复合地基和常规桩筏基础相比,对于桩顶预留净空桩筏基础工作性状,研究发现在桩顶与筏板接触前,桩顶预留净空桩筏基础工作性状与刚性桩复合地基相似;桩顶与筏板接触后,其工作性状与常规桩筏基础相似。试验条件下,桩顶与筏板之间接触、设置褥垫层、预留净空(或可压缩垫块)不同连接方式可显著影响桩间土的压缩及桩土相对滑移,对上述三者来说,桩身下部桩、土相对滑移量(桩端刺入量)依次减小。更多还原

【Abstract】 Field model tests are performed on the rigid pile composite ground(RPCD),the conventional piled raft(CPR) and the piled raft with gap between pile top and raft(PRGPR) to study the raft-pile-soil interaction with different structural connection forms between the pile top and the raft.The settlement of raft,soil beneath the raft and soil surrounding the piles groups at different depths under different load levels are measured.Also,the axial forces of the pile and the raft-soil contact pressure are recorded through the whole loading process.Based on the analysis of the measured data,the load transfer mechanism and settlement characteristics of piled raft concerned are studied.Compared with the working behaviors of RPCD and CPR,the test results show that the working behaviors of PRGPR are quite similar to those of RPCD before the raft and pile top are contacted.However,it will start to work similarly to CPR after the raft and pile top are contacted.The different connection forms between the pile top and raft can significantly affect the compaction of soil among piles and thus can affect the slip at the interface between the piles and surrounding soil.For piled raft with each of the three types of raft-pile top connection respectively,the PRGPR will yield the largest pile end penetration and the CPR will yield the smallest.更多还原