State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian　 116024,China

针对混凝土管片受压区高度小和受压区钢筋未达到屈服极限问题,提出了混凝土管片极限承载力计算模型。在轴力和弯矩共同作用下,将混凝土管片简化为偏心受压柱,建立了管片截面力平衡和弯矩平衡表达式。基于管片截面平面变形假定,建立了受压区钢筋应力与受压区高度和混凝土极限应变之间的关系。通过2个地铁隧道管片工程算例,分析讨论了轴力对受压区高度、受压区钢筋应力和管片极限承载力的影响。研究表明,混凝土管片的极限弯矩随着轴力的增加而增加;混凝土管片的最不利荷载组合为最大弯矩与最小轴力的组合。混凝土管片受压区的钢筋往往没有达到屈服极限,有时甚至处于受拉状态;现有模型假设受压区的钢筋屈服与钢筋的实际应力状态差异较大,新的计算模型能够准确计算受压区的钢筋的应力。

Taking into account the problems of small compressive depth and less than yielding strength for bars located in the compressive zone of concrete segments,a new computing model is proposed to evaluate the ultimate bearing per- formance of concrete segments. Under the actions of both axial force and bending moment,the concrete segment is sim- plified to column with eccentric compressive loading,and the expressions for force balance and bending moment bal- ance are derived. Based on the plane deformation assumption,the relationships between the stress of reinforced bars in the compressive zone and compressive depth in the concrete segment are proposed. Through two practical examples of underground tunnels lined by concrete segments,the influences of the axial force on compressive depth,the stress of reinforced bars and ultimate bearing performances of concrete segments are investigated. The computing results show that the ultimate bending moment of concrete segment increases with the increase of axial force,and the worst loading combination is the maximum bending moment with minimum axial force. The stress of reinforced bars in compressive zone cannot reach the yielding limit of material and are even in tensile state in some loading cases. The difference be- tween the assuming stress and practical stress for existing model is obvious. The proposed computing model can pre- cisely calculate the stress of reinforced bars in the compressive zone.

国家重点基础研究发展计划资助项目(2015CB057804)；国家自然科学基金资助项目(11572079)；工业装备结构分析国家重点实验室开放基金资助项目(S14206)；

Li Shouju,Yu Shen,Liu Junhao. Computing model for influence of axial force on ultimate bearing performance of concrete segments[ J]. Journal of China Coal Society,2017,42(1):236-241.