围岩和衬砌劣化作用下隧道底部结构动力响应

Dynamic Response of Tunnel Bottom Under Deterioration of Surrounding Rock and Lining

采用有限元方法对比分析了列车振动荷载作用下不考虑与考虑衬砌和围岩劣化时隧道底部结构动力响应。结果表明:整体来看,列车通过时衬砌劣化对隧道底部结构动力响应影响较小,从开始服役到服役100年,隧道底部竖向位移基本不变,振动加速度先减小后增大,动应力逐渐减小;围岩劣化对隧道底部结构动力响应影响明显,从开始服役至服役100年,隧道底部竖向位移逐渐增大,振动加速度先增大后减小,动拉应力先减小后增大,动压应力逐渐增大;考虑围岩劣化作用时,服役60年左右隧道底部结构振动加速度变化显著,动拉应力急剧增大,对隧道底部结构极为不利,因此隧道服役后期应加强隧道底部及周围岩体的监测与病害防治。

A finite element method was used to compare and analyze the dynamic response of tunnel bottom structure under the vibration load of the train with and without considering the deterioration of lining and surrounding rock.The results show that,on the whole,the deterioration of lining has little effect on the dynamic response of the tunnel bottom structure during the passage of the train.The vertical displacement of the tunnel bottom remains basically unchanged from the beginning to 100 years of service,while the vibration acceleration firstly decreases and then increases,and the dynamic stress gradually decreases.The deterioration of surrounding rock has a significant impact on the dynamic response of the tunnel bottom structure.From the beginning to 100 years of service,the vertical displacement at the tunnel bottom gradually increases,the vibration acceleration firstly increases and then decreases,the dynamic tensile stress decreases firstly and then increases,and the dynamic compressive stress gradually increases.When considering the deterioration of surrounding rock,the vibration acceleration of tunnel bottom structure changes significantly after about 60 years of service,and the dynamic tensile stress increases sharply,which is extremely unfavorable to the tunnel bottom structure.Therefore,monitoring and disease prevention of the tunnel bottom and the surrounding rock should be strengthened in the later stage of tunnel service.