深基坑组合型钢内支撑构件平面内稳定分析  

In-plane stability analysis of assembly steel struts in deep excavation

作　　者：李永华[1] 肖云豪 章伟豪 揭一鸣 LI Yonghua;XIAO Yunhao;ZHANG Weihao;JIE Yiming(Architectural and Civil Engineering Institute,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学建筑工程学院,江西南昌330031

出　　处：《铁道科学与工程学报》2021年第12期3201-3209,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51168037)。

摘　　要：深基坑组合型钢内支撑构件平面内受力特性相当于具有多道弹性支撑杆的钢柱,弹性支撑杆的刚度为托架水平抗侧移刚度,该刚度一般小于支撑的门槛刚度,刚度贡献在设计时常被忽略。采用能量法对设有2至10道弹性支撑杆的轴压钢柱的平面内稳定性能进行分析,推导对应不同屈曲半波数的弹性临界荷载与支撑杆刚度之间的通解,在此基础上进一步得出不同屈曲半波数转折点对应的支撑刚度。与传统曲线拟合公式相比,计算精度有一定提高。分别对长度120 m,下设9道托架、长度60 m,下设4道托架的2个组合型钢内支撑构件进行平面内稳定分析。研究结果表明:当托架采用排架形式时,组合型钢内支撑构件计算长度系数降低5.6%~15%,但当托架采用刚架形式时,内支撑构件的计算长度系数可降低28%~50%,充分利用托架的水平抗侧移刚度可产生明显的经济效益。In deep excavations, the mechanical characteristic of the composite steel struts is equivalent to the steel column with multiple elastic braces. The rigidity of the elastic brace is the horizontal lateral stiffness of the bracket, which is generally less than the threshold stiffness and is often ignored in design. The in-plane stability of steel columns with 2~10 elastic braces was analyzed by energy method, and the general solution between the elastic critical load and the stiffness of the braces in different buckling wave numbers was obtained. On this basis,the brace stiffness of turning point with different buckling half-wave numbers was obtained,and the accuracy was obviously improved compared with the traditional curve fitting formula. The in-plane stability analysis of two combined steel struts with 120 m length and 9 brackets, 60 m length, and 4 brackets were carried out respectively.The results show that the decline of effective length factor of combined steel struts is 5.6%~15% when the bracket is bent, but the decline of effective length factor is 28%~50% when the bracket is portal frame. Making full use of the lateral stiffness of the bracket can bring obvious economic benefits.

关 键 词：深基坑 组合型钢内支撑 屈曲 弹性支撑 临界荷载 

分 类 号：TU470.3[建筑科学—结构工程]