隧道施工中围岩与支护结构的黏弹性分析

VISCOELASTIC ANALYSIS OF THE STRESS AND DISPLACEMENT IN TUNNEL SURROUNDING ROCK AND SUPPORT DURING THE PROCESS OF TUNNEL CONSTRUCTION

结合某高速公路隧道设计与施工,利用黏弹性理论,对隧道围岩与支护结构时间相依应力与位移进行了研究.首先,将隧道开挖后围岩受力分析视为具有初始应力、在洞周位移作用下的边值问题,导出了隧道时间相依的围岩与支护结构应力与位移,结果表明,其应力和位移与隧道围岩和支护结构间相互作用相关.然后,利用变形协调条件,导出了隧道围岩与支护结构间的相互作用,结果表明,围岩、初期支护与二次衬砌之间的相互作用不仅与围岩和衬砌的材料性质、结构尺寸相关,而且与施做初衬和二衬的时间相关.最后,结合具体隧道设计与施工,利用本文时间相依应力,对围岩应力释放与支护施做时机、载荷分配与支护结构受力分析进行了探讨,给出了不同荷载分担比下二次衬砌的受力与变形,为隧道施工与设计提供参考.

In this paper,time-dependent stress and displacement in tunnel surrounding rock and sup-port have been studied using viscoelasticity. Firstly, stress analysis of the surrounding rock and support is treated as a boundary value problem with the initial stress under the action of the displacement in the tun-nel surrounding rock after tunnel excavation,and the time-dependent stress and displacement in tunnel sur-rounding rock and support are derived, which depend on the interaction between tunnel surrounding rock and support. Then,the interaction between tunnel surrounding and support is derived by compatibility of deformation, showing it not only depends on the material property and size of tunnel surrounding and sup-port, but also the time of making supports. Finally, the present method is employed to guide the design and construction of a special tunnel.