特大断面公路隧道地震动力响应分析

以西南地区某高速公路特大断面隧道地震设防为研究背景,通过有限元动力计算方法,考虑隧道施工过程形成的应力场作为动力分析的初始应力场,同时在动力分析中考虑静力和动力分析的人工边界转换处置,采用地下结构静-动力分析方法对隧道进行了地震动力响应分析。模型分析了特大断面公路隧道在地震动力作用下的衬砌加速度响应、第一主应力和第三主应力响应、静力到动力的塑性发展情况。分析结果表明,特大断面隧道的仰拱区域在地震振动中是薄弱部位,在施工中围岩压力释放充分有利于隧道抗震,二次衬砌作为安全储备在振动中发挥主要作用。研究结果可为工程实际提供一定的参考意义。

Analysis on Seismic Response of a Super-large Section Tunnel in Highway

Taking the seismic fortification of a super-large section highway tunnel in Southwest China as the research background, the stress field formed by the tunnel construction process was considered as the initial stress field of the dynamic analysis by the finite element method. Besides, considering the disposal of the artificial boundary conversion in the static calculation and dynamic calculation, the seismic response of the tunnel was analyzed with the static-dynamic analysis method in the underground structure. In the model of the super-large section highway tunnel, the acceleration response of the lining, the response of the first principal stress and the third principal stress, and the development of plasticity in the static calculating stage and the earthquake stage was researched. It was shown that the inverted arch area of the super-large section tunnel was a weak area in the earthquake vibration, the release of the surrounding rock pressure in the construction phase was fully beneficial to the tunnel earthquake resistance, the secondary lining played the leading role as the safety reserve in the earthquake. The research results could provide some reference for engineering practice.