【作者】 刘冬林；

【导师】 郑刚；

【作者基本信息】 天津大学 ， 岩土工程， 2007， 博士

【摘要】 复合桩基和刚性桩复合地基均可实现桩土共同承担上部结构荷载,由于二者在桩顶与基础之间的构造形式不同,桩土相互作用方式存在一定的差异。随着复合桩基和刚性桩复合地基在高层建筑筏板基础中的广泛应用和按沉降控制对地基进行设计的理念进一步推广,桩顶与基础的不同构造形式对所形成地基工作性状的影响成为人们关注的热点,因此,开展对桩顶与基础不同构造形式下桩土相互作用研究具有理论和现实意义。本文通过现场大比例尺模型试验,对非均匀荷载作用下带上部结构高层建筑筏板基础复合桩基和刚性桩复合地基、非均匀布桩刚性桩复合地基和均匀荷载作用下刚性基础桩顶预留净空复合桩基的工作性状进行了研究,测量了不同荷载级别下筏板(或刚性载荷板)沉降、筏板(或刚性载荷板)内部和筏板(或刚性载荷板)外侧地基土不同深度的沉降、筏板外侧地基沿水平方向在地面位置和桩端平面标高位置地基土沉降,同时对不同荷载级别下桩身不同深度的轴力和桩间土应力也进行了测试;分析了筏板总沉降和差异沉降、桩土应力分布、桩土荷载传递、桩土荷载分担比以及预留净空值对复合桩基工作性状的影响,通过对复合桩基和刚性桩复合地基、非均匀布桩刚性桩复合地基、桩顶预留净空复合桩基工作性状的对比,研究了桩顶与基础在不同构造形式下的桩土相互作用,得出了复合桩基和刚性桩复合地基、非均匀布桩刚性桩复合地基及桩顶预留净空复合桩基桩土相互作用规律,提出了桩顶预留净空复合桩基设计方法,通过与三维有限元沉降分析结果和模型试验实测沉降结果相比,所提方法沉降计算结果与模型试验和有限元分析结果吻合较好。更多还原

【Abstract】 Both composite pile foundation and rigid composite foundation can accomplish bearing super structure load by pile and soil. There are some difference in interaction of pile and soil because of different structural form between pile top and foundation in composite pile foundation and rigid pile composite foundation. Along with composite pile foundation and rigid pile composite foundation having been in great use in high building with raft foundation and foundation design method according to foundation settlement having been further adopted, the influence of different structural form between pile top and foundation on foundation work behavior have becomed people’s hot spot. It has theoretical and practical meaning to research pile and soil interaction between pile top and foundation in different structural form.Through big scale model test in site, this paper researched the work behavior of composite pile foundation, rigid pile composite foundation and nonuniform arrangement rigid pile composite foundation in high building raft foundation with super structure under nonuniform load on raft foundation. The work behavior of composite pile foundation with space between pile top and foundation was also researched in rigid foundation form under uniform load. The settlements were measured on raft foundation(or rigid load board),different depth subgrade under raft foundation(or rigid load board) and different depth subgrade beside raft foundation(or rigid load board) under different load level. The axial force of pile in different depth and soil stress under foundation were measured under different load level, too. It was analyzed the influence of raft total settlement, differential settlement, pile-soil stress distribution, pile-soil load transition, pile-soil load sharing scale and the space between pile top and foundation on the work behavior of composite pile foundation. Comparing the work behavior of composite pile foundation and rigid pile composite foundation, nonuniform arrangement rigid pile composite foundation and composite pile foundation with space between pile top and foundation, the pile-soil interaction of different structural form of pile top and foundation were researched and the laws of pile-soil interaction were obtained from composite pile foundation and rigid pile composite foundation, nonuniform arrangement rigid pile composite foundation and composite pile foundation with space between pile top and foundation. The design method was put forward on composite pile foundation with space between pile top and foundation. The result of settlement using design method given in this paper was in good correspondence with settlement result of model test measured in site and three dimension finite element analyzed.更多还原