隧道中气囊阻漏的工作机理及模型试验研究

近年来,地下隧道工程发展迅速,在建设和使用过程中的突发事件也层出不穷。地下隧道常经过含水丰富的土层或岩层裂隙发育地带,因此容易发生渗漏或者涌水突泥的问题。为减少工程损失,需尽快将涌水区隔离,为进一步的处置争取时间。采用大尺寸橡胶气囊进行隧道挡水,是通过快充而膨胀的气囊与隧道内壁之间产生的摩擦力抵消水压力,将水阻隔在气囊一端,避免涌水面积扩大。本文假设气囊材料不可拉伸,内部气体满足理想气体状态方程,通过分析气囊的受力情况和边界条件,对气囊在充气过程中和一端有外力时的形状和受力特点试验和理论研究,得到气囊受到外压时整体形状和内部气压的理论公式,以及外压与内压的关系,提出气囊阻水的设计计算方法。通过模型试验对变化规律、公式和气囊失稳方式进行了对比分析,研究结果表明,隧道中气囊正常工作需同时满足3个控制条件:(1)一端的外压必须小于气囊的内压;(2)气囊的张拉力必须小于气囊材料的抗拉强度;(3)外荷载推力必须小于气囊与隧道壁之间的最大摩阻力。通过理论研究所得的气囊失效机理和内压增长规律与模型试验所得结果有较高的一致性,研究成果可作为隧道中大尺寸胶囊设计的依据。

Analytical and Model Test Study on the Behavior of Airbags Used for

With the development and utilization of underground space, the security problem is increasingly prominent in urban underground railway construction and operation. The tunnels are in the aquifer or rock fracture zone, so the problems of water and mud bursting have occurred during the construction and operation of the tunnel. Therefore, it is necessary to segregate the gushing water area as soon as possible to gain time for further disposal. The method to stop water with rubber airbags is efficient, and the contact area between the surface of the airbag and the inner wall of the tunnel will produce frictional force to resist the fluid pressure in the tunnel. This paper assumes that the airbag material can’t be stretched, the internal gas meets the state equation of ideal gas, combined with the boundary conditions in the tunnel of the airbag and the stress condition, the shape and the force characteristics of the airbag under the action of external pressure are studied. The formula of the shape change and internal pressure increase of the airbag from the beginning to the limit state is obtained, and the relationship between the external pressure and internal pressure is put forward. The theoretical formula is verified by the model test. Research results show that the airbag functions perfectly only if the following conditions are satisfied: (1) The air pressure inside the airbag must be greater than the resisted fluid pressure in the tunnel; (2) The tensile force induced in the airbag must be less than the strength of the material making the bags. (3) The frictional force must be greater than the fluid pressure. The results of the model test are in good agreement with the theoretical analysis. The research results can be used as the basis for the design of large size airbags in tunnels.