真空负压静力试桩方法关键技术试验研究  

Study of key technologies of vacuum negative-pressure static pile load test

作　　者：史永跃 王奎华[2] 董天文[3] 马显春[1] 黄永威[1] SHI Yong-yue;WANG Kui-hua;DONG Tian-wen;MA Xian-chun;HUANG Yong-wei(China Railway Southwest Research Institute Co.,Ltd.,Chengdu,Sichuan 611731,China;Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou,Zhejiang 310058,China;School of Civil Engineering,Liaoning Technical University,Fuxin,Liaoning 123000,China)

机构地区：[1]中铁西南科学研究院有限公司,四川成都611731 [2]浙江大学滨海与城市岩土工程研究中心,浙江杭州310058 [3]辽宁工程技术大学土木工程学院,辽宁阜新123000

出　　处：《岩土力学》2020年第5期1699-1708,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金面上项目(No.51579217,No.51779217)。

摘　　要：现有的静力试桩方法主要有堆载法、锚桩反力架法和自平衡法3种,且各自都存在明显的不足。为了弥补传统基桩静载试验的不足,设计并加工了一套能在工程实践中应用的真空负压静力试桩的反力装置,并进行了原型桩堆载和真空负压静载试验。在试桩上安设了钢筋应力计、桩底土压力盒和桩底位移杆监测传感器及装置,借鉴了地基真空预压排水预压密封系统的措施,形成了有效的密封反力系统。分析了试桩在加载过程中的荷载-位移(Q-s)曲线、位移-时间(s-lgt)曲线,以及轴力、桩侧摩阻力和桩端摩阻力的分布规律。试验表明,桩侧摩阻力的发挥与抽真空过程密切相关。由于负压平台的刚度、压力传递和密封效果原因,真空负压最大加载量级与理论值存在一定差距,针对上述问题提出了相应的解决方案和改进措施。The conventional static pile load testing methods include Kentledge, reaction piles and bi-directional methods, whereas each of these methods has inevitable disadvantages. A vacuum static load testing is developed to avoid the disadvantages of these traditional methods. A set of reaction devices is designed for vacuum negative-pressure static pile load test, which can be used in engineering practice. Pile foundation loading and vacuum negative-pressure static load tests were carried out. Vibrating wire rebar stress meters, earth pressure cells and displacement bar monitoring sensors are installed on the pile. The effective sealing reaction system is formed by referring to the measures of foundation vacuum preloading drainage preloading sealing system. The Q-s curve, s-lgt curve, the distribution of axial force, lateral resistance and terminal resistance in the loading process of the tested pile are analyzed. The tests show that the response of lateral friction of the pile is closely related to the vacuum pumping process. Due to the stiffness, pressure transfer and sealing effect of the negative pressure platform, there is a certain gap in the maximum loading magnitude between the vacuum negative-pressure and the related theoretical value. The corresponding solutions and improvement measures are proposed for the above problems.

关 键 词：真空负压静力试桩 Q-S曲线 钢筋应力计 土压力盒 密封反力系统 

分 类 号：TU473[建筑科学—结构工程]