沉管隧道GINA止水带结构形式对比研究

为研究GINA止水带结构形式对其水密性的影响,对目前普遍采用的4类GINA止水带进行轴压与轴、偏压组合状态下的有限元数值模拟。采用超弹单元和接触单元模拟橡胶材料和接触效应,对底板开孔、底板带肋以及本体开孔3种结构变化对GINA止水带受力和止水效果的影响进行分析。研究结果表明:1)GINA止水带底肋与钢板接触位置的接触应力最小,是防水的薄弱环节;2)在底板和本体开孔能够使得GINA止水带底板的接触应力分布更为均匀,但开孔尺寸不宜过大,且应均匀布设;3)底尖肋型GINA止水带的初期止水效果差,当止水带较高时,容易产生倾覆;4)本体孔洞型GINA止水带能够缓解尖肋的应力集中,但由于本体刚度小,承受侧向水压力的能力差。

Comparative Study on Structural Types of GINA Gaskets Used in Immersed Tunnel

FEM is used on 4 types of GINA gaskets under working conditions of axial compression and axial lateral compression, so as to study the influence caused by structural types of GINA gaskets on water tightness. An analysis is made on the influence of 3 structural variations of GINA gaskets, including gaskets with body openings, gaskets with bottom openings, and gaskets with tip ribs, on the stressing and water proofing efficiency, by using super elastic elements and contacting elements to simulate the rubber materials and the contacting effects. The study results show that: 1) The contacting pressure at the point between the tip rib and the steel plate is the smallest, which is the weak point of waterproofing; 2) The distribution of the contacting pressures on the bottom of GINA gaskets can be more uniform if openings are installed on bottoms or bodies of gaskets, however diameters of openings should be proper and openings should be distributed uniformly; 3) The primary water proofing effect of GINA gasket with tip ribs is poor, and overturning may occur when a gasket is high; 4) GINA gaskets with body openings can relieve the stress concentration caused by tip ribs, however, they have poor capacity to bear the lateral water pressures because of their smaller body stiffness.