张明聚, 杨萌, 王锡军. 基坑工程内支撑活络端结构革新性研究[J]. 工程力学, 2018, 35(S1): 88-94,119. DOI: 10.6052/j.issn.1000-4750.2017.05.S012
引用本文: 张明聚, 杨萌, 王锡军. 基坑工程内支撑活络端结构革新性研究[J]. 工程力学, 2018, 35(S1): 88-94,119. DOI: 10.6052/j.issn.1000-4750.2017.05.S012
ZHANG Ming-ju, YANG Meng, WANG Xi-jun. Innovative study on active node of steel tube bracing system for braced excavations[J]. Engineering Mechanics, 2018, 35(S1): 88-94,119. DOI: 10.6052/j.issn.1000-4750.2017.05.S012
Citation: ZHANG Ming-ju, YANG Meng, WANG Xi-jun. Innovative study on active node of steel tube bracing system for braced excavations[J]. Engineering Mechanics, 2018, 35(S1): 88-94,119. DOI: 10.6052/j.issn.1000-4750.2017.05.S012

基坑工程内支撑活络端结构革新性研究

Innovative study on active node of steel tube bracing system for braced excavations

  • 摘要: 在内撑式基坑工程中,常用的打入钢楔式活络端存在整体性差、点接触受力、承载力小、刚度弱等缺陷,不利于基坑工程变形和稳定控制。为改进活络端结构,设计研发了一种螺栓紧固锥楔式(BFW)活络端。该文首先阐述其结构、功能及工作原理,计算其承载力与刚度,采用数值模拟分析其力学特征;然后,设计制作3组足尺试件,在试验室进行弹性加载试验与最不利工况下极限承载力加载试验,测试了不同调节长度及轴心与偏心荷载作用下的承载力与刚度,得到了其破坏形态;最后,将BFW活络端的力学参数与常用的不同型号钢支撑的力学参数进行对比,研究了其适用性。研究结果表明:BFW活络端结构简单,受力明确,承载力和刚度大;通过理论分析、数值模拟和室内加载试验,证明其工作原理可靠;与不同规格的钢支撑配套使用,满足“强节点、弱构件”结构设计理念。该文给出的BFW活络端的型号适用609/630型号钢支撑,若与800型号钢支撑配套使用,需要设计更强活络端。

     

    Abstract: In the excavation projects with inner bracing, the commonly used active node (by plugging into steel wedges) has many defects, such as poor integrity, point contact, low bearing capacity, and weak stiffness. It is not helpful for the deformation and stability control of deep excavation. In order to improve the active node structure, an innovative Bolt Fasten Wedge (BFW) active node was developed. First, the structure, function and working principle of the BFW active node was introduced. Its bearing capacity and stiffness was calculated by theoretical derivation and its mechanical characteristics were analyzed by numerical simulation. Then, 3 sets of full-size specimens of the BFW active node were designed and manufactured. Elastic loading test and ultimate bearing capacity loading test under the most unfavorable conditions were carried out in the lab. The bearing capacity and stiffness under different adjusting lengths and axial or eccentric loads were tested. The destruction form of the specimens was investigated. Finally, the bearing capacity and stiffness of the BFW active node were compared with those of different types of commonly used steel tube bracings, and the applicability of the BFW active node was evaluated. The results show that the BFW active node has a simple structure, a clear way of stress, good bearing capacity and strong stiffness; its structure is proved to be reliable in working principle by the theoretical analysis, numerical simulation and laboratory loading tests. Both the bearing capacity and stiffness of the BFW active node are larger than those of different types of commonly used steel tube bracings, which meets the structural design concept of ‘strong node and weak component’. The BFW actice node described in this paper is suitable for 609/630 steel tube. For 800 steel tube, a stronger type is needed.

     

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