地下室增层二桩一柱承台截桩次生内力计算方法研究  

Study on Calculative Method of Secondary Internal Forces Caused by Piles Cutting-off in Basement Story-adding of Pile Cap Propped by Two Piles under a Column

作　　者：薛圣雅 杨予[1] 吴希 Xue Shengya;Yang Yu;Wu Xi(School of Civil Engineering and Architecture, Zhejiang Sci-tech University, Hangzhou310018, China)

机构地区：[1]浙江理工大学建筑工程学院,杭州310018

出　　处：《特种结构》2018年第2期27-32,共6页Special Structures

基　　金：国家自然科学基金项目(41472284);浙江省自然科学基金项目(LY17E080025)

摘　　要：既有建筑地下室增层是城市地下空间开发的一个新思路,该过程常涉及截桩托换,截桩施工时控制结构内力变化对结构安全至关重要。本文研究了地下室增层桩基托换过程中由截桩引起的新增下柱次生内力。首先采用限元方法对截桩过程进行了数值模拟,而后分析了不同的连系梁/承台线刚度比对下柱次生内力的影响,结果表明当忽略梁板作用将承台简化为刚体、桩端简化为简支时轴力增量计算值最大;据此推导了两种二桩一柱承台下柱的截桩次生内力计算方法,可根据工程实际需要选用。Basement story-adding in existing buildings is a new idea for the development of urban underground space. The process involves such underpinning construction procedures as piles cutting-off. When pieces of piles are being cut off, controlling internal forces variation of newly constructed structure has significant meaning to building safety. Secondary internal forces caused by piles cutting-off in the process of foundation underpinning for basement story-adding was studied. Firstly, finite element method was used to simulate the process of piles cutting-off, then, the influence of different linear stiffness ratio of beam to pile cap on the secondary internal forces of the lower column was discussed. The result indicated that the increment of axial force has maximum value when the end of pile is simplified as simply supported and pile cap is simplified as rigid body. Hence two sencondary internal forces calculation methods were deduced, which can be selected according to actual needs of project.

关 键 词：地下室增层 截桩 内力增量 计算方法 

分 类 号：TU473.1[建筑科学—结构工程]