侧向荷载作用下损伤隧道粘钢加固效果试验研究

Test Study on the Reinforcement Effect of Bonding Steel to Damaged Tunnels under the Lateral Loads

为了研究侧向荷载作用下损伤隧道衬砌粘钢加固效果,采用1∶10的模型试验,研究了侧向荷载作用下隧道衬砌结构和不同损伤状态粘钢加固结构的变形、破坏模式。试验结果表明:侧向荷载作用下,隧道衬砌结构破坏模式为脆性破坏,破坏发展过程为拱腰开裂—拱肩脆性剪坏—拱腰延性受弯破坏;衬砌结构拱顶和左右侧边墙—拱腰处裂损集中发育,截面刚度快速衰减,是结构的脆弱点和危险点;粘钢加固后,结构拱腰处结合面剪应力引起的粘钢剥离是加固结构失稳的主要因素;结构剩余承载力占比为30%时粘钢加固结构承载力未提高,在剩余承载力占比为48%时粘钢加固结构承载力提升4.1%,在剩余承载力占比为60%时加固结构承载力提升10.2%。因此,侧向压力作用下隧道损伤衬砌采用粘钢加固后结构的承载力提升皆不明显,加固效果有限,侧向荷载引起的衬砌损伤不宜采用粘钢加固。

To research the reinforcement effect of bonding steel to the damaged linings of tunnels under lateral loads, a 1∶10 model test was conducted, and the modes of deformation and damage of the tunnel lining structure under lateral loads and the steel-bonded structure in different states of damage were researched. The test results showed that under lateral loads, the damage mode of the tunnel lining structure was brittle failure, and the damage development process was as follows: arch waist cracking — brittle shear failure of arch shoulder — damage to arch waist ductility and bending;damage was concentrated on the crown of the lining structure and the side wall-waist on the left and right sides, and the section stiffness was rapidly attenuated, which was the vulnerability and dangerous point of the structure;after steel was bonded for reinforcement, the stripping of bonded steel caused by the shear stress of the bonding surface at the structure waist was the major factor causing the instability of the reinforced structure;when the remaining bearing capacity proprtion was 30%, the bearing capacity of the structure reinforced by bonded steel was not increased;when the remaining bearing capacity proprtion was 48%, the bearing capacity of the reinforced structure was increased by 4.1%;when the remaining bearing capacity proprtion was 60%, the bearing capacity of the reinforced structure was increased by 10.2%. Consequently, after the damaged tunnel lining was reinforced with bonded steel under the lateral pressure, the bearing capacity was not significantly improved and the reinforcement effect was limited, and the lining damage caused by lateral loads should not be reinforced by bonding steel.