地面爆炸下软硬不均地层超大直径盾构隧道动力响应分析

Dynamic response analysis of ultra-large diameter shield tunnel in uneven soft and hard strata under surface blast load

近年来港口危化品堆场爆炸灾害频出,盾构隧道面临着潜在的地面爆炸荷载威胁。采用多物质任意拉格朗日-欧拉(arbitrary Lagrangian-Eulerian,ALE)流固耦合建模方法,考虑到螺栓、钢筋、混凝土管片等多种结构复杂的非线性行为,建立了地面爆炸荷载下超大直径盾构隧道精细化模型,通过对炸药当量、埋深、爆源偏心距进行参数分析,研究了地面爆炸荷载对所处上软下硬地层隧道结构的动力响应和损伤过程,并对管片接缝处的变形模式及螺栓的塑性发展进行了分析。结果表明:在地面爆炸荷载下盾构隧道损伤由顶部向两肩发展,纵向接缝形成错动,环向接缝开合交替;区别于整体结构,超大直径盾构隧道在地面爆炸荷载冲击下应着重加强隧道两肩和接缝处的防护。

In recent years,there are frequent explosions in hazardous chemical storage yards at ports,and shield tunnels are facing potential surface blast load threats.Here,considering complex nonlinear behaviors of various structures of bolts,steel bars and concrete segments,the multi-material arbitrary Lagrangian-Eulerian fluid-structure coupled modeling method was adopted to establish a refined model of ultra-large diameter shield tunnel under surface blast load.By analyzing parameters of explosive equivalent,burial depth and eccentricity of blast source,dynamic response and damage process of tunnel structure in upper-soft and lower-hard strata under surface blast load were studied,deformation mode at segment joints and plastic development of bolts were analyzed.The results showed that under surface blast load,damage of shield tunnel develops from top to two shoulders,longitudinal joints are staggered and circumferential joints open and close alternately;being different from the overall structure,ultra-large diameter shield tunnel should focus on strengthening protection at tunnel shoulders and joints under surface blast load.