软弱地层综合管廊三维非线性地震反应特性研究

Three-dimensional Nonlinear Seismic Response Characteristics of Utility Tunnel under Soft-weak Strata

软弱地层综合管廊在强震作用下易发生破坏。考虑土体非线性及水的影响,以苏通GIL综合管廊工程为依托,采用三维线性梁单元模拟螺栓与钢筋,对地震动进行幅值标定,建立三维精细化有限元模型,并根据不同地震动输入方式及强度,从衬砌应力分布、张开量及结构损伤角度分析综合管廊非线性地震反应特性。研究结果表明,45°共轭方向与拱腰位置处管廊受力较大,横向、纵向地震动作用下,随着地震动强度的增加,应力增加明显;横向地震动输入对管廊环间张开量的影响较小,当地震动达到峰值附近时,张开量增长明显,并在一定范围内波动;横向地震动对管廊结构损伤的影响较大,峰值加速度达0.3 g时,管廊内部结构在两端连接处及中间支撑处连接点出现拉压变形。

Under the condition of soft-weak strata,the utility tunnel is prone to damage under strong earthquakes.Considering the influence of soil nonlinearity and water,three-dimensional linear beam elements are used to simulate bolts and steel bars,the amplitude of ground motion is calibrated,and a three-dimensional refined finite element model is established.The nonlinear seismic response characteristics of the utility tunnel are analyzed from the perspective of stress distribution,opening amount,and structural damage.The results show that from the stress distribution,it can be seen that the utility tunnel is subjected to greater stress in the 45°conjugate direction and the position of the arch waist.Under the action of two-way ground motion,the stress increases more obviously with the increase of the ground motion intensity.The lateral ground motion input has little effect on the opening amount between the utility tunnel.When the ground vibration is near the peak value,the opening amount increases significantly and fluctuates within a certain range.The lateral ground motion has a great influence on the damage of the tunnel structure.When the peak acceleration reaches 0.3 g,the inner structure of the utility tunnel has tensile and compressive deformation at the connection points of both ends and the connection point of the intermediate support.