采用缓粘结预应力筋的新型抗拔桩受力特性研究  

Study on mechanical characteristics of new type of uplift pile with gently bonded prestressed reinforcement

作　　者：毛宗原 郭豪 张宏刚 高识涵 陈穆 MAO Zongyuan;GUO Hao;ZHANG Honggang;GAO Shihan;CHEN Mu(China Building Technique Group Co.,Ltd.,Beijing 100013,China;Beijing Sub-central Station Comprehensive Hub Construction Management Co.,Ltd.,Beijing 101100,China)

机构地区：[1]中国建筑技术集团有限公司,北京100013 [2]北京城市副中心站综合枢纽建设管理有限公司,北京101100

出　　处：《建筑结构》2023年第3期138-145,共8页Building Structure

基　　金：国家自然科学基金重大项目(52090081)。

摘　　要：介绍了一种采用缓粘结预应力筋的新型抗拔桩,对该新型抗拔桩的施工工艺进行了总结,并且通过现场试验对比分析了无粘结预应力抗拔桩和缓粘结预应力抗拔桩的荷载变形特性、受力机理和桩身裂缝分布。试验结果表明:缓粘结预应力抗拔桩的单桩承载力比无粘结预应力抗拔桩提高了3.7%~26.7%,并且其顶部位移满足一般建筑物的抗浮要求;无粘结预应力抗拔桩在试验过程中桩身整体先处于受拉状态,当荷载大于预应力时,抗拔桩从下部桩身开始呈现受压状态,缓粘结预应力抗拔桩在试验过程中桩身整体处于受拉状态,并且下部桩身为主要受力部位,抗拔桩受力效果较好;两种试桩在试验过程中桩身未出现裂缝;与无粘结预应力抗拔桩相比,缓粘结预应力抗拔桩有更好的整体性,能够有效防止由于钢绞线变形导致抗拔桩与承台锚固部位产生裂缝,保证桩顶钢绞线与外部隔离,防止钢绞线产生锈蚀。A new type of uplift pile with gently bonded prestressed reinforcement was introduced. The construction technology of this new type of uplift pile was summarized, and the load deformation characteristics, stress mechanism, pile crack distribution of unbonded prestress uplift pile and gently bonded prestressed uplift pile were analyzed through field tests. The test results show that the single pile bearing capacity of gently bonded prestressed uplift pile is 3.7%~26.7% higher than that of unbonded prestressed uplift pile, and its top displacement meets the anti-floating requirements of general buildings. During the test process, the unbonded prestressed uplift pile is in a tensile state as a whole at frist. When the load is greater than the prestress, the uplift pile begins to be in a compressive state from the lower pile body. In the test process, the whole pile body of gently bond prestress is in the tensile state, and the lower pile body is the main bearing part, so the froce effect of the uplift pile is better. No cracks appear in the pile body of the two kinds of test piles in the test process. Compared with unbonded prestress uplift pile, the gently bonded prestress uplift pile has better integrity, which can effectively prevent the cracks in the anchor position between the prestress uplift pile and the pile cap caused by the deformation of the steel strands, ensure the isolation of the steel strands at the top of the pile from the outside and prevent the corrosion of the steel strands.

关 键 词：无粘结预应力 缓粘结预应力 抗拔桩 单桩静载荷试验 

分 类 号：TU473.14[建筑科学—结构工程]