卸载工况下槽钢加固盾构管片的受力性能数值分析

NUMERICAL ANALYSIS OF MECHANICAL PROPERTIES OF CHANNEL-STEEL-REINFORCED SHIELD SEGMENTS UNDER UNLOADING CONDITIONS

槽钢加固作为新型管片加固方法,能够对盾构隧道管片结构的收敛变形起到限制作用。考虑多环管片间的环间作用力,运用MIDAS GTS NX软件建立三环错缝精细化管片模型,从管片累积顶底收敛变形、螺栓和槽钢应力、管片塑性节点发展情况等方面衡量槽钢加固管片的加固效果。研究结果表明,槽钢加固能有效限制管片的顶底收敛变形,最大加固效率可达50%;卸载过程中槽钢和螺栓共同承担卸载导致的应力,卸荷较小时槽钢加固能有效减小管片螺栓应力;管片环缝间为剪切破坏,槽钢加固可以降低管片环间作用力的影响,延缓管片混凝土和螺栓出现塑性变形,可为同类工程加固提供参考借鉴。

As a new segment reinforcement method,channel steel reinforcement can limit the convergence deforma⁃tion of the shield tunnel segment structure.Considering the inter-ring force between multi-ring segments,a three-ring staggered segment refined segment model is established by the MIDAS GTS NX software.The reinforce⁃ment effect of the channel reinforced segment is measured from the aspects of the segment’s cumulative top and bot⁃tom convergence deformation,the stress of bolts and channel steel,and the development of plastic joints of the seg⁃ment.The research results show that the channel steel reinforcement can effectively limit the top and bottom conver⁃gence deformation of the segment,and the maximum reinforcement efficiency can reach 50%.During the unloading process,the channel steel and the bolt share the stress caused by the unloading.When the unloading is small,the channel steel reinforcement can effectively reduce the stress of the segment bolts.Channel steel reinforcement can re⁃duce the influence of the force between segment rings and delay the plastic deformation of segment concrete and bolts for shear failure between shield tunnel segments.It can provide reference for the reinforcement of similar projects.