公路隧道二次衬砌钢筋环向间距对结构安全性影响分析

Influence of Circumferential Reinforcement Spacing of Secondary Lining on Structural Safety of Highway Tunnel

为了研究二次衬砌钢筋环向间距变化引起隧道衬砌结构内力的变化规律及特点,以某已建隧道二次衬砌Va支护为例,分别对二次衬砌环向钢筋设计间距、随机±30 mm和±50 mm工况下的应力变化进行弹塑性数值模拟分析。计算结果表明,钢筋间距的变化不改变二次衬砌整体结构受力,但在隧道拱脚等位置会出现严重的应力集中,并随着随机间距的增大,应力变化越大,表观现象为应力集中处的表层混凝土剥落,从而影响结构的正常使用。

In order to study the change rule and characteristics of internal force of secondary lining structure caused by the change of circumferential reinforcement spacing. Taking Va support of secondary lining of one built tunnel as an example, elastic-plastic numerical simulation of stress changes was carried out under design spacing of secondary lining steel bars, random 依30 mm and 依50 mm conditions respectively. The results show that the change of steel spacing does not change the stress of secondary lining, but there will be serious stress concentration at the arch foot of the tunnel, and with the increase of random spacing. The stress change will become more and more serious,and the apparent phenomenon is the surface concrete spalling at the stress concentration, which affects the normal use of the structure.