深厚砂层桩端后注浆灌注桩现场试验研究  

Field test of post-grouting bored pile in thick sand layer

作　　者：鹿存亮 Lu Cunliang(Shanghai Geotechnical Investigations&Design Institute Co.,Ltd.,Shanghai 200093,China)

机构地区：[1]上海勘察设计研究院(集团)有限公司,上海200093

出　　处：《工程勘察》2023年第3期7-11,39,共6页Geotechnical Investigation & Surveying

摘　　要：深厚砂层中钻孔灌注桩施工存在泥皮厚、桩端沉渣难控制等问题。本文以中原某项目为例,对钻孔灌注桩采用桩端后注浆工艺进行加强处理,并在现场进行了一系列竖向抗压静载荷试验和抗拔试验。试验表明:在深厚密实砂层中采用桩端后注浆工艺,再满足一定量的注浆量后可同时达到加固桩端和桩侧的效果,有效提高桩端阻力和桩侧摩阻力;竖向抗压承载力极限值综合提高系数可达3.5,抗拔承载力极限值提高系数可达2.0;桩端沉降大小与注浆量密切相关。本研究可为后续类似深厚砂层钻孔灌注桩桩端后注浆的设计提供参考和借鉴。There are some problems in the bored pile construction in deep sand layer, such as thick slurry coating and bottom sediment control. In this paper, a case study of a bored piles improved by post-grouting at the pile bottom is carried out. A series of vertical compression and pull-out static load test are carried out on site. The test results show that the pile end and pile side can be strengthened simultaneously using post-grouting technique in the deep and dense sand layer, and the pile shaft friction and pile end resistance can be effectively improved after a certain amount of grouting;the comprehensive increase coefficient of the ultimate value of the vertical compressive bearing capacity can reach 3.5, and the increase coefficient of the ultimate value of the uplift bearing capacity can reach 2.0;the settlement of pile is closely related to the amount of grouting. This study can provide reference for the design of post-grouting at the pile bottom of bored pile in similar geological conditions.

关 键 词：深厚砂层 桩端后注浆 现场载荷试验 双套管 沉降杆 钢筋应力计 

分 类 号：TU473[建筑科学—结构工程]