卵石层地基上开口PHC管桩的应用分析  

Application analysis of open-ended PHC pipe pile on pebble layer foundation

作　　者：丁小伟 高军程 李胜利 DING Xiaowei;GAO Juncheng;LI Shengli(China Coal Xi'an Design Engineering Co.,Ltd.,Xi'an 710054,Shaanxi,China;China Vanke Co.,Ltd.,Shenzhen 518000,Guangdong,China)

机构地区：[1]中煤西安设计工程有限责任公司,陕西西安710054 [2]万科企业股份有限公司,广东深圳518000

出　　处：《地基处理》2024年第5期481-487,共7页Journal of Ground Improvement

摘　　要：陕西石川河Ⅰ级阶地,地表以下约15 m深存在厚度10~13 m、工程力学性质较好的卵石层,如何有效利用该层良好的承载潜力是设计面临的问题。在某项目的地基设计中,参考已有的试验研究成果及工程经验,分析开口PHC管桩在卵石层中的端阻力承载性状,通过原位静载试验验证,在相应的沉桩条件下,中短开口管桩沉入卵石层中可形成土塞效应,当桩端沉降量达到桩径的4.9%~6.9%时,卵石层的实际极限端阻力较规范值提高1.49~1.93倍,管桩的竖向抗压承载力提高27%~46%。建筑物封顶后的沉降观测结果验证管桩方案可行,避免了素土桩作业造成的环境污染,节省了造价和工期,具有良好的社会效益和经济效益。Grade I terrace of the Shichuan River in Shaanxi Province has a pebble layer with a thickness of 10-13 meters and good engineering mechanical properties at a depth of about 15 meters below the surface.Effectively utilizing the good bearing potential of this layer is a design challenge.In the foundation design of a specific project,referring to existing experimental research and engineering experience,the tip resistance bearing behaviors of open-ended PHC pipe piles in the pebble layer were analyzed.Through in-situ static loading tests,it was verified that under corresponding pile driving conditions,the settlement of medium and short open-ended pipe piles in the pebble layer can form a soil plug effect.When the pile end settlement reaches 4.9%-6.9%of the pile diameter,the actual ultimate tip resistance of the pebble layer increases by 1.49-1.93 times compared to the standard value,the vertical bearing capacity of the pipe pile increases by 27%-46%.The settlement observation results after completion of the building construction verify that the pipe pile scheme is feasible,avoiding environmental pollution caused by the soil pile foundation scheme,saving cost and construction period,and having good social and economic benefits.

关 键 词：开口管桩 土塞效应 卵石层端阻力 静载试验 沉降观测 

分 类 号：TU473[建筑科学—结构工程]