地铁列车动载作用下盾构隧道底部溶洞对管片动力性能的影响

Influence of the Tunnel Bottom Cave on Shield Segment Dynamic Performance under Metro Dynamic Load

由于我国岩溶地质分布广泛,随着城市轨道交通建设规模不断扩大,越来越多的盾构隧道不可避免地穿过岩溶发育区。目前,针对隐伏型岩溶的盾构隧道在运营期的动力响应及寿命评估的研究仍较为缺乏,尤其是运营期地铁列车在长期高频反复荷载作用下,隧道底部不同工况的溶洞对管片动力性能的影响尚未得到关注。以广州地铁9号线岩溶地质为例,制定了隧道底部存在溶洞时的详细数值试验方案,采用数值模拟手段对运营期地铁列车反复振动作用下盾构隧道底部隐伏溶洞大小及距离变化时管片的动力响应进行分析,并结合经验公式对管片结构的疲劳寿命进行预测,可为类似问题提供参考和借鉴。

Due to the wide distribution of Karst geology in China,it is inevitably that many shield tunnels are passing through Karst development areas with the expansion of urban rail transit construction scale.Since the lack of researches on the dynamic response and life assessment of the hidden Karst shield tunnel in operation,the influence of Karst cave under different conditions on the dynamic performance of shield segment is not noticed,especially when the running train is on long-term and high frequency cyclic load.In this paper,a detailed numerical test scheme is formulated based on the Karst geology on Guangzhou metro Line 9,the shield dynamic performance influenced by the size and distance changes of the hidden Karst caves beneath metro tunnel is simulated.Combined with empirical formula,the dynamic response and the fatigue life of shield segment under repeated metro vibration are predicted.