重载列车对隧道裂损衬砌承载性能的影响研究

为定量分析重载列车动载作用下隧道裂损衬砌裂缝的演化机制和承载性能的变化规律,采用扩展有限元与直接循环法相结合的方法模拟裂缝在列车荷载作用下的扩展路径,并通过模型试验对方法的有效性和准确性进行验证。模型试验与数值模拟的误差仅为3.7%,表明该数值模拟方法较为精确。研究发现： 1）在重载列车动载作用下,裂损衬砌仰拱处的动力响应相较于衬砌其他位置会更为剧烈,裂损衬砌仰拱处的安全系数与衬砌其他位置相比则更小,因此裂损衬砌仰拱位置为重载列车动载下的危险部位; 2）重载列车轴重对裂损隧道衬砌的动力响应影响比初始裂缝深度及车速对裂损隧道衬砌的动力响应影响更为明显,而裂损衬砌的安全性能受初始裂缝深度影响比受轴重及车速影响更为显著。

Effect of Heavy Haul Train on Bearing Capacityof Cracked Tunnel Lining

In order to obtain the fracture evolution mechanismand variation law of bearing capacity of cracked lining under heavy haultrain load, a numerical simulation technique based on the combination ofextended finite element method and direct circulation method is adopted toquantitively analyze the propagation path of cracks. Through comparing thenumerical simulation with the model test site results, it shows that the erroris found to be only 3.7%, thus the propagation path of cracks under train loadcan be simulated accurately. Research results show that: (1) The dynamicresponse at the cracked lining invert is more intense than that at other partsof the lining and the safety factor at the cracked lining invert is smallerthan at other parts of the lining under heavy haultrain load;therefore, the position of cracked lininginvert is the dangerous position under dynamic load of heavy haul train. (2) The influence of axle load on the dynamic responseof cracked tunnel lining is more obvious than that of initial crack depth andspeed, and the safety performance of cracked lining is more significantlyaffected by initial crack depth than by axle load and speed.