高速铁路隧道基底软岩动力响应特性分析

Dynamic Response Properties of Soft Bedrock of High-Speed Railway Tunnel

采用动力有限元法,建立了隧道-围岩相互作用的计算模型,分析不同列车运行速度和不同隧道底部结构型式下的高速铁路隧道基底软岩的动力响应特征,着重研究隧道基底软岩的加速度、动应力特性和动力损伤演化规律.结果表明:隧道基底软岩的振动响应幅度随距离的增大而减小,列车振动荷载对隧道基底仰拱范围内的围岩影响较大,影响深度约为基底以下5m范围.列车运行速度的改变对隧道基底软岩加速度的影响较为明显,而基底软岩动应力和损伤量的变化较小;随着仰拱矢跨比的减小,底部结构逐渐变得扁平,致使基底围岩动应力和损伤量变大.

An analysis is performed using the dynamic finite calculation model, which takes into consideration of the interaction between tunnel structure and surrounding rock. The dynamic responses of the base soft rock, the acceleration, dynamic stress and damage of the soft bedrock in particular, are investigated. The calculation re- suits show that the soft bedrock dynamic responses decrease with the increase of distance from the vibration source, with a greater influence on the surrounding rock under the bration in tunnel is about 5m below the basement. The changes acceleration and less effect on dynamic stress and invert, and influence depth caused by train vi- of train speed have more influence on bedrock damage. The bottom structure flattens progressively with the decrease of invert arch rise - span ratio, resulting in greater dynamic stress and damage of the bedrock