高速铁路CFG桩复合地基新型预制圆板桩帽试验研究

对高速铁路CFG桩复合地基中的新型预制圆板桩帽进行了现场试验研究,结果表明:预制圆板桩帽的承载性能由受弯承载力控制,其受弯主裂缝在桩帽顶面大致沿直径方向发展,在桩帽侧面呈上宽下窄,并向下延伸;采用FLAC有限元模型和提出的简化方法计算桩帽的受弯承载力是有效的,桩帽受弯开裂的计算值与现场试验实测值符合较好;提出的4种桩帽均可满足项目工点的复合地基承载力的要求,其安全系数分别为1.33,1.76,2.38及3.11。

STUDY ON THE NEW PRECAST CIRCULAR-PLATE PILE CAP IN THE CFG PILE COMPOSITE FOUNDATION OF HIGH-SPEED RAILWAY

The field tests on new precast circular-plate pile caps in the CFG pile composite foundation of high-speed railway were carried out. The results show that the bearing capacity of pile caps is dependent on their flexural behavior. The flexural cracks develop in diameter directions on the top surfaces of the caps,while extend downwards on the side faces,with wide upper part and narrow lower part. The calculated flexural cracking loads are consistent with the field test results,which indicates that the FLAC model and the simplified method in this paper are effective. All of the four types of pile caps can satisfy the load-bearing capacity requirements,and the safety factors are 1.33,1.76,2.38 and 3.11,respectively.