第29卷第6期 岩 土 力 学 Vol.29 No. 6 2008年6月 Rock and Soil Mechanics Jun. 2008

文章编号：1000－7598－(2008) 06－1697－04

钻孔后压浆技术在苏通大桥基础工程中的应用

布克明1,2，殷坤龙1，龚维明3

（1.中国地质大学 工程学院，武汉430074；2.交通部第二公路勘察设计院，武汉 430056; 3. 东南大学 土木工程学院，南京210096）

摘 要：钻孔灌注桩后压浆技术，使水泥浆液在高压下渗透、充填和挤密，与沉渣、泥皮、桩周和桩端土体发生物理化学固结，增大了土体和桩端的强度，改变了桩的受力类型，提高了桩侧摩阻力和端阻力，从而提高了单桩的承载力。在苏通大桥超长大直径桩中应用了桩底后压浆技术。通过试桩静载试验，决定在工程施工中采用U型压浆管方案。试桩结果表明，压浆后极限承载力测试值是压浆前的1.48～2.0倍，压浆后端阻力是压浆前的2.46～7.21倍，表明利用后压浆技术达到了节约工程投资、提高工程施工质量及可靠性的目的，并产生了较大的技术经济效益和良好的社会环境效益，这将促进我国公路桥梁建设的桩基技术迈向一个新台阶。

关 键 词：钻孔灌注桩；后压浆技术；苏通长江大桥；桩端阻力；桩侧摩阻力 中图分类号：TU 472 文献标识码：A

Post-grouting technique for piled foundation:

Case history of Su-Tong Bridge

BU Ke-ming, YIN Kun-long1, GONG Wei-ming3

1,2

(1. Engineering Faculty, China University of Geosciences, Wuhan 430074, China; 2. China Communications Second Highway Survey, Design and Research Institute,Wuhan 430056, China; 3. College of Civil Engineering, Southeast University, Nanjing 210096, China)

Abstract: Post-grouting technique has a wide range application to piled foundations. The principle of post-grouting technique is as follows: through grouting cement into bottom of bored pile or around pile body, the loose material such as deposit and slime during pile construction can be strengthened; and it can highly increase frictional resistance and end bearing capacity of pile. Post-grouting technique was successfully employed in the piled foundation of Su-Tong Bridge, a huge bridge under construction which connects Suzhou City and Nantong City in Jiangsu Province, China. According to the results of static load tests, the U-shape grouting pipe was used in the project for the piles’ bottom grouting. After grouted, values of the ultimate bearing capacity of the tested piles were increased up to1.48-2.0 times the ones of un-grouted bored piles. For end bearing capacities, their values were increased up to 2.46-7.21 times. It can be drawn a conclusion that through using post-grouting technique, it saves investment, improves construction quality and reliability, and brings considerable economic benefits and well social environment effects as well. Key words: bored pile; post-grouting technique; Su-Tong bridge; pile tip resistance; side friction

1 引 言

钻孔灌注桩是当前高层建筑和桥梁基础的主要桩型。传统灌注桩成孔工艺导致桩底沉渣和桩侧泥皮等固有缺陷，造成桩端阻力和桩侧摩阻力显著降低。钻孔灌注桩后压浆技术可有效地消除桩底沉渣和桩侧泥皮的不利影响，是一种有效提高钻孔灌注桩性能、节约工程成本的先进施工工艺。在国外，20世纪20年代开始，英、美等发达国家开始研究后压浆施工工艺并取得了成功。到目前为止，已形成了几十种成熟的施工工艺，并制定了完善的设计

方法和施工规范。从20世纪80年代开始，在我国越来越多的高层建筑的桩基础应用后压浆技术来提高桩的承载力，其施工工艺及计算方法也得到不断的提高。

2 桩端后压浆技术机制分析

后压浆按在桩身的位置可分为桩端压力注浆、桩侧压力注浆、桩端桩侧联合压浆3种。桩端后压浆技术的作用机制表现在以下几方面：

（1）向桩端压注水泥浆时，水泥浆液是由下而

收稿日期：2006-07-18

作者简介：布克明，男，1966年生，博士研究生，主要从事桩基工程检测方面的研究。E-mail: bukeming@dtcsc.com