逆作法“一柱三桩”托换梁受力机理研究

Study on Mechanical Mechanism of Underpinning Beam with"One Column and Three Piles"By Reverse Construction Method

为研究“一柱三桩”新型竖向支撑体系中托换梁的力学行为,选取B0和B1层的托换梁的上下皮钢筋进行了自动化实时监测。监测结果表明:上下同步逆作施工过程中托换梁结构均处于安全状态;托换梁下方土方开挖工序和格构柱割除工序对托换梁影响较大,其余施工工况对托换梁影响较小;逆作法基坑施工过程中,托换结构整个断面均处于受压状态,现有设计将其直接简化为简支梁计算是偏于保守的。

To study the mechanical behavior of underpinning beams in the new vertical bracing system of"one column and three piles",the upper and lower steel bars of the underpinning beams in floors B0 and B1 are selected for automatic real-time monitoring.The monitoring results show that the underpinning beam structure is in a safe state in the process of synchronous reverse construction from top to bottom;the earthwork excavation process and lattice column removal process under the underpinning beam have a greater impact on the underpinning beam,while other construction conditions have a smaller impact on the underpinning beam;the whole section of the underpinning structure is under pressure during the foundation pit construction with reverse construction method and it is conservative to directly simplify it to simply supported beam in the existing design.