破碎围岩条件下铁路隧道单层衬砌结构力学特征研究

摘要

研究目的:文章以合武铁路大别山隧道为背景,对Ⅳ级围岩条件下采用的单层衬砌结构的接触力学特征、不同施工阶段的受力特征以及围岩稳定性等进行研究,并对单层衬砌结构的力学特征进行探索,以期为类似工程的设计和施工提供参考.研究结论:(1)相对于复合式衬砌而言,单层衬砌接触压力普遍较大,最大压力易出现于拱脚处,最小压力易出现于仰拱处,而其二衬的内力显著小于复合衬砌.(2)单层衬砌结构内力在隧道施工的不同阶段,初期支护与二衬的内力先按时间分配,后按刚度分配.(3)隧道左右拱腰侧与拱脚处的围岩的YAI值较小,容易发生失稳,应加以防范.%Research purposes: Taking the Dabieshan Tunnel of the Hefei - Wuhan Railway as the background, the study is done on the contact mechanical characteristics and the load bearing characteristics of single - layer lining in the different construction stages as well as on the stability of surrounding rocks for the purpose of clarifying the mechanical characteristics of single - layer lining to provide the reference to the design and construction of similar tunnels.Research conclusions: (1) Compared with the composite lining structure, the contact pressure of single - layer lining structure is obviously bigger, and the maximum pressure is easy to occur at arch foot while the minimum prssure is easy to occur on inverted arch.The internal force of the secondary single - layer lining is obviously smaller than the composite lining.(2) The inner force in single - layer lining is firstly distributed following the supporting time and then distributed following the rigidity.(3) The YAI values of the surrounding rocks on the left and right arch web sides and arch foot are relatively small, and where is easy to destabilize, so the relative measure should be taken.