预压托换桩加固及顶升纠偏工程实践  

FOUNDATION REINFORCEMENT AND BUILDING RECTIFICATION OF DEVIATION BY JACK-UP AND PRELOADING UNDERPINNING PILE

作　　者：刘丽萍[1] 李向阳[2] 王德伟 燕菲 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]同济大学地下建筑与工程系,上海200092 [3]陕西现代建筑设计研究院,陕西西安710048 [4]陕西建达疑难工程公司,陕西西安710055

出　　处：《岩石力学与工程学报》2005年第15期2795-2801,共7页Chinese Journal of Rock Mechanics and Engineering

摘　　要：西安市某住宅楼是在原3层砖混结构上增建至7层框架结构式房屋,两种结构体系没有完全脱离开,又由于设计时地基处理不当,导致建筑物刚封顶即严重倾斜,倾斜率为18.6‰,沉降速率为9.15mm/d,随时存在倒塌的危险。为使房屋恢复正常使用,经研究后决定采用钢筋混凝土预压托换桩加固及顶升纠偏方案。以此工程为例,提出顶升纠偏中预压托换桩设计公式;详细介绍了纠偏方案的选定、钢筋混凝土预压托换桩顶升纠偏的设计方法、施工工艺、顶升监测与控制以及顶升施工中的技术难点及采取的对策等。经过3d顶升施工后,使房屋的倾斜率稳定在0.53‰,沉降速率小于0.0077mm/d,房屋基本上恢复了正常使用。经过5a多使用证明,在黄土地区采用预压托换桩法加固或纠偏类似工程问题是可行的。A 3-story brick concrete structural building was added to 7-story in Xi'an City, Shaanxi Province; and the new-added part is a frame structure. Because two different structural systems are not separated completely and the designer adopted unsuitable ground treatment method, the building became leaning seriously when the major structure was completed. The inclination ratio and settlement rate of building are up to 18.6‰ and 9.15 mm per day, respectively; and the building is bound to collapse. The scheme of rectifying deviation by jack-up and by preloading underpinning pile was employed after investigation for sake of safety. Based on this case, the following aspects are investigated: the formula to determine the numbers of underpinning piles for rectifying leaning building is presented; scheme choice of rectifying deviation, designing method, construction procedure of preloading underpinning pile, jacking monitoring and controlling are introduced in derail; difficult factors and corresponding problems during jacking construction are provided. After 3-day jack-up construction, the inclination ratio of building is steady at 0.53‰ and settlement rate is less than 0.0077 mm per day and tends to be stable. After five years regular service, it can be concluded that preloading underpinning pile is feasible to reinforce or rectify similar structures and project in loess region.

关 键 词：基础工程 顶升纠偏 预压托换桩 地基加固 工程实例 

分 类 号：TU472.2[建筑科学—结构工程]