飞机降落冲击荷载作用下高铁隧道疲劳寿命及抗减振措施研究

Fatigue Life and Anti-Vibration Measures of High-Speed Railway Tunnel under Aircraft Landing Impact Load

为解决在上方飞机降落冲击荷载作用下高铁隧道衬砌结构抗减振问题,依托时速350 km成自高铁下穿天府机场东二跑道的区间隧道工程,通过数值模拟研究在上方飞机降落冲击荷载作用下高铁隧道衬砌结构的疲劳寿命以及相应的抗减振措施。研究表明:1)B747-400型飞机在单次重着陆过程中,高铁隧道衬砌位移峰值为1.2 mm,附加第一主应力峰值为328 k Pa,附加第三主应力峰值为417 k Pa,均出现在拱顶位置处;2)在长期飞机重着陆作用下,衬砌拱顶部位最早出现疲劳损伤,其次为边墙部位,疲劳寿命为88年,建议通过提升自身衬砌混凝土强度等级或设置减振层等方式加以改善;3)采用提高衬砌结构混凝土强度等级的方法抗振效果显著,而采用泡沫混凝土减振层的方法则需设置一定厚度后才起作用,建议减振层厚度为0.5 m,弹性模量控制在0.7 GPa以上,方可达到隧道设计使用年限规定要求。

To investigate anti-vibration response of high-speed railway tunnel lining structure under the impact load of aircraft landing,a case study is conducted on the high-speed railway tunnel section with a speed of 350 km/h crossing underneath East 2nd Runway of Tianfu airport using numerical simulation method,and corresponding anti-vibration measures are proposed.The research results reveal the following:(1)The peak displacement of the lining of the highspeed railway tunnel is 1.2 mm during a single heavy landing of the B747-400 aircraft,the peak value of the additional first principal stress is 328 kPa and the that of the additional third principal stress is 417 kPa,which all appear at the tunnel crown.(2)Under the action of long-term aircraft heavy landing,the fatigue damage occurs at the lining crown first,followed by the sidewall,and the fatigue life is 88 years.It is suggested to improve it by raising the specification of self-lining concrete or setting vibration reduction layer.(3)The method of improving the concrete specifications of lining structure is effective in reducing vibration.The method of using foam concrete damping layer needs a certain thickness.It is suggested that the thickness of the damping layer is 0.5 m and the elastic modulus is above 0.7 GPa,so that the design service life of the tunnel can be met.