喀斯特地区新型异形灌注桩承载特性与影响因素试验研究  

Experimental Study on Bearing Behavior and Influencing Factors of a Special-shaped Cast-in-place Pile in Karst Area

作　　者：张福友 冯健雪 陆志宇 杨济铭 梅国雄[1,2,3] ZHANG Fu-you;FENG Jian-xue;LU Zhi-yu;YANG Ji-ming;MEI Guo-xiong(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning 530004,China;Guangxi Key Laboratory of Disaster Prevention and Engineering Safety,Guangxi University,Nanning 530004,China;Architectural Engineering College,Guizhou Minzu University,Guiyang 550025,China)

机构地区：[1]广西大学土木建筑工程学院,南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,南宁530004 [3]广西大学广西防灾减灾与工程安全重点实验室,南宁530004 [4]贵州民族大学建筑工程学院,贵阳550025

出　　处：《长江科学院院报》2021年第2期92-99,共8页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金项目(51578164,51878185);广西自然科学基金创新研究团队项目(2016GXNSFGA380008)。

摘　　要：喀斯特地区灌注桩施工常常发生漏浆且造成成桩质量不佳与承载力不足的严重后果。根据喀斯特地区地基连通孔道分布广泛的特点,提出了一种新型灌注桩——布袋桩,并设计基岩模型进行布袋桩成桩试验,探讨布袋桩成桩可行性。在成桩可行的基础上进行8组静载模型试验,研究布袋桩的承载特性与影响因素。试验结果表明:布袋桩成桩质量良好,通过布袋桩与等直径桩对比分析发现布袋桩的极限承载力为等直径桩的1.5倍,同等荷载条件下布袋桩的沉降远小于等直径桩;同时,试验分析了布袋桩荷载传递规律与承载影响因素,发现桩身轴力在枝状体上下界面处明显降低,其枝状体结构增强了桩侧摩擦性能,荷载传递特性具有明显的时间效应;布袋桩承载力与枝状体的长度、数量及分布位置埋深呈正相关关系。研究结果为喀斯特地区桩基础的设计与施工提供一种新思路。The leakage of slurry during cast-in-place pile construction in karst area often results in poor quality and insufficient bearing capacity of pile.In view of the wide distribution of connected channels in the karst area,we propose a new type of cast-in-place pile in dendritic shape with bags socketed into the karst caves.We probed into the feasibility of such bag-pile by designing bedrock model for pile-forming test,and on this basis,we further investigated the bearing characteristics and influencing factors of bag-pile via eight groups of static load model tests.Results demonstrated good quality of cast-in-place bag-pile.The ultimate bearing capacity of the proposed bag-pile is about 1.5 times that of ordinary pile of equal diameter,and the settlement of bag-pile is much smaller than that of ordinary pile of equal diameter under the same load conditions.Besides,the axial force of bag-pile body obviously reduced at the upper and lower interfaces of the dendritic structure which enhanced the side friction performance of the pile.Load transfer is of obvious time effect.The bearing capacity of bag-pile is positively correlated with the length,number,and buried depth of the dendritic structure.

关 键 词：灌注桩 布袋桩 承载特性 成桩试验 变形性能 影响因素 喀斯特地区 

分 类 号：TU473.1[建筑科学—结构工程]