非挤土嵌岩预应力高强度混凝土管桩的桩端承载性能研究  

Bearing capacity of pile toe of non-displacement rock-socketed PHC pipe piles

作　　者：凌造 唐孟雄 胡贺松 刘春林 李波 苏定立 LING Zao;TANG Meng-xiong;HU He-song;LIU Chun-lin;LI Bo;SU Ding-li(Guangzhou Construction Co.,Ltd.,Guangzhou,Guangdong 510030,China;Guangzhou Municipal Construction Group Co.,Ltd.,Guangzhou,Guangdong 510030,China;Guangzhou Institute of Building Science Group Co.,Ltd.,Guangzhou,Guangdong 510440,China)

机构地区：[1]广州建筑股份有限公司,广东广州510030 [2]广州市建筑集团有限公司,广东广州510030 [3]广州市建筑科学研究院集团有限公司,广东广州510440

出　　处：《岩土力学》2024年第1期97-107,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.51908225,No.52208336);中国博士后科学基金项目(No.2021M690784);广州建筑集团科技计划项目(No.2020-KJ002,No.2021-KJ040,No.2021-KJ041,No.2022-KJ002)。

摘　　要：施工装备和工艺的不断创新使得非挤土嵌岩预应力高强度混凝土(prestressed high-strength concrete,简称PHC)管桩逐渐得到推广和应用。为揭示嵌入中微风化岩PHC管桩的桩端承载机制,以随钻跟管工法桩为背景,基于泥质粉砂岩地区5组桩径为500 mm的PHC管桩桩端现场静载破坏性试验,分析了不同条件下嵌岩PHC管桩的桩端承载性能及宏观破坏模式,并提出桩端承载力计算方法。试验表明:对于采用敞口桩靴的PHC管桩,未封底时,敞口桩靴削弱了PHC管桩桩端承载性能,呈现刺入岩基的破坏,极限荷载下桩端沉降为11~15 mm;混凝土封底后,显著提高了桩端承载性能,极限承载力较非封底时提升340%,封底混凝土和桩靴的桩端阻力分担比分别为78%和22%,桩端呈整体剪切破坏。基于Hoek-Brown强度准则,提出了嵌岩PHC管桩桩端承力简化计算方法,计算精度得到了试验验证,可供非挤土嵌岩PHC管桩的设计与施工参考。With the continuous innovation of construction equipment and technology,non-displacement rock-socketed prestressed high-strength concrete(PHC)pipe pile has been gradually popularized and applied.To reveal the bearing mechanism of pile toe of rock-socketed PHC pipe pile,five groups of static load destructive tests of pile toe of PHC pipe pile with pile diameter of 500 mm in argillaceous siltstone area were carried out under the background of the drilling with prestressed concrete pipe pile.The bearing capacity and macroscopic failure mode of the pile toe of rock-socketed PHC pipe piles under different conditions were analyzed,and the calculation method of the pile toe bearing capacity was proposed.The test results show that when PHC pipe pile with open pile shoe is used and the pile end is not sealed,the open pile shoe weakens the bearing capacity of pile toe of PHC pipe pile.The pile shoe pierces into the bedrock,and the settlement of the pile toe is 11−15 mm under the ultimate load.After pouring concrete to seal the bottom,the bearing capacity of pile toe is significantly improved.The ultimate bearing capacity is 340%higher than that without bottom sealing,and the pile toe resistance share ratios of bottom sealing concrete and pile shoe are 78%and 22%,respectively.The pile toe is subjected to overall shear failure.Finally,based on the Hoek-Brown strength criterion,a simplified calculation method for the bearing capacity of pile toe of rock-socketed PHC pipe piles is put forward.The calculation accuracy of this method has been verified by the tests,and the calculation method can be used as a reference for the design and construction of non-displacement rock-socketed PHC pipe piles.

关 键 词：预应力高强度混凝土管桩(PHC管桩) 嵌岩桩 桩端 静载试验 承载性能 

分 类 号：TU473[建筑科学—结构工程]