考虑落石入射能量-角度-位置的棚洞结构精细化动力响应研究

Study on Fine Dynamic Response of Shed Tunnel Structure Considering Incident Energy-angle-position of Rockfall

为了揭示落石冲击棚洞结构动力响应特性,文中以某高速公路Y隧道洞口工程为依托,采用LS-DYNA软件建立三维棚洞计算模型,探究顶板、立柱、立柱基础、侧墙基础、横向系梁结构冲击应力扩散规律,分析顶板、立柱在不同落石入射速度、角度、位置下力学响应机制。结果表明,立柱上端内侧与顶板腹部正中单元均处于冲击应力集中状态,冲击能量遵循“就近损伤、瞬态脉冲性、滞后性、逐级衰减”特征。落石侵彻垫层深度、冲击加速度、顶板腹部单元峰值应力均与入射速度呈近似正相关。冲击速度>18m/s时,结构处于危险状态。

In order to reveal the dynamic response characteristics of shed tunnel structure impacted by rockfall,LS-DYNA software is used to establish a three-dimensional shed tunnel calculation model based on the Y tunnel entrance project of an expressway.The impact stress diffusion law of the roof,column,column foundation,side wall foundation and transverse tie beam structure are explored,and the mechanical response mechanism of the roof and column is analyzed under different rockfall incidence speed,angle and position.The results show that the inner side of the upper end of the column and the central element of the top plate are in the state of impact stress concentration,and the impact energy follows the characteristics of“nearby damage,transient impulsivity,hysteresis and gradual attenuation”.The penetration depth,impact acceleration and the peak stress of the abdominal element of the roof are all positively related to the incident velocity.In addition,when the impact speed is greater than 18 m/s,the structure is in a dangerous state.