基坑工程钢支撑高脚螺栓-模袋混凝土固支端力学性能试验研究  

Experimental Study on Mechanical Properties of High-Foot-Bolt&Mould-Package Concrete Fixed Support Ends for Steel Support in Foundation Pit Works

作　　者：郭彩霞[1,2] 刘文杰 张明聚[2] 李鹏飞[2] 高云昊[2] 单余含 GUO Caixia;LIU Wenjie;ZHANG Mingju;LI Pengfei;GAO Yunhao;SHAN Yuhan(Chongqing Research Institute of Beijing University of Technology,Chongqing 401121;Beijing University of Technology,Beijing 100124)

机构地区：[1]北京工业大学重庆研究院,重庆401121 [2]北京工业大学,北京100124

出　　处：《现代隧道技术》2023年第5期277-286,共10页Modern Tunnelling Technology

基　　金：重庆市自然科学基金(CSTB2023NSCQ-MSX0528);国家自然科学基金(51978018)。

摘　　要：在城市建设明挖基坑工程中,大量采用内撑式支护结构,其中钢支撑端部节点是控制基坑变形和稳定的关键。为了改进支撑端部的受力方式,研发了高脚螺栓-模袋混凝土固支端,阐述了其结构组成和特点,加工4组试件进行室内试验,研究了试件在轴向和偏心荷载作用下的力学性能,获得了试件的破坏形态、荷载-位移曲线和荷载-应变曲线,得到了该固支端的弹性承载力和刚度。试验结果表明:(1)该固支端的设计承载力高于4000 kN,超过ϕ609钢支撑轴向设计承载力,满足强节点设计要求,且固支端屈服后,具有良好的塑性变形能力,极限承载力超过6500 kN;(2)试件的最终破坏形式为钢管短接段鼓曲、模袋混凝土开裂及高脚螺栓弯曲,增加模袋混凝土成型预压应力和强度可提高固支端承载力;(3)所研发的固支端结构简单、性能稳定,有助于提高基坑施工的安全性。In the open excavation works of foundation pit in urban area,a large number of internal support structures are used,among which the steel support end nodes are the key to controlling deformation and stability of the founda⁃tion pit.In order to improve the load-carrying mode of the support end,a high-foot-bolt&mould-package concrete fixed support end is developed.Its structural composition and characteristics are explained,and four sets of speci⁃mens are processed for indoor test.The mechanical properties of the specimens under axial and eccentric loads are studied.Failure mode,load-displacement curve,and load-strain curve of the specimens are obtained,and the elas⁃tic bearing capacity and the stiffness of the fixed support end are obtained.The test results indicate that:(1)the de⁃signed bearing capacity of the fixed support end is higher than 4000 kN,exceeding the designed axial bearing ca⁃pacity ofϕ609 steel support and meeting the requirements of strong node design.After yielding of the fixed support end,it has good plastic deformation capacity,with an ultimate bearing capacity larger than 6500 kN;(2)The final failure modes of the specimen include buckling of the short connecting section of steel pipe,cracking of the mouldpackage concrete,and bending of the high-foot bolt.Increasing the compressive pre-stress and the strength of the mould-package concrete can improve the bearing capacity of the fixed support end;(3)The developed fixed support end has a simple structure and stable performance,which helps to improve the safety of foundation pit construction.

关 键 词：基坑工程 钢支撑 模袋混凝土 固支端 力学性能 

分 类 号：TU473[建筑科学—结构工程]