软硬突变地层盾构隧道地震响应特性研究

发布时间：2018-05-02 12:38

本文选题：盾构隧道 + 软硬突变地层　；参考：《西南交通大学》2015年硕士论文

【摘要】：近年来,随着城市地铁交通快速发展,盾构法以开挖安全,施工迅速逐渐成为地铁隧道修建的首选施工方法。与此同时,盾构隧道的结构形式逐渐增多,穿越的地层也越来越复杂。过去,人们认为地下结构具有良好的抗震性能,但20世纪以来,地下结构在几次大震中遭受较为严重的破坏,在对震害研究后发现,地下结构并不是“免震结构”。因此有必要对地下结构的地震响应特征、抗震性能开展深入研究。本文依托厦门地铁二号线工程,采用数值仿真分析与振动台试验相结合的方法,对软硬突变地层中盾构隧道的地震响应特征进行了研究。首先,在Abaqus有限元分析软件中建立盾构隧道的三维混合模型,模拟不同地震波、地震波传播方向、软硬交界面倾角变化对隧道结构及地层动力响应的影响。模拟结果表明：在地震波作用下,软、硬地层具有相同的加速度响应规律,但软弱地层的加速度放大效应更为显著；在软硬地层交界处,隧道结构的应力会发生突变；当剪切地震波垂直于隧道轴线入射时,结构应力突变幅度最大；软硬地层交界面倾角的变化也会造成隧道结构附加主应力的改变,但影响程度并不显著；接头螺栓的动力响应对地震波输入方向较为敏感,当地震波从沿着隧道轴线传播变化到垂直于隧道轴线传播,螺栓从主要受剪切力作用转变为受轴向拉伸作用。然后,开展了盾构隧道的振动台模型试验,试验结果同数值仿真结果一致：对于不同物理力学参数的地层而言,地层条件较弱一侧的加速度放大趋势更为明显,处于同一高程处的地层具有相同的加速度响应特征,位于软硬地层交界面处的隧道结构会产生应力集中现象。
[Abstract]:In recent years, with the rapid development of urban subway traffic, shield tunneling has become the preferred construction method for subway tunnel construction. At the same time, the structure form of shield tunnel is increasing gradually and the stratum passing through is becoming more and more complex. In the past, it was thought that the underground structure had good seismic performance, but since the 20th century, the underground structure has suffered more serious damage in several large earthquakes. After studying the earthquake damage, it is found that the underground structure is not a "shockproof structure". Therefore, it is necessary to study the seismic response characteristics and seismic performance of underground structures. Based on Xiamen Metro Line 2 project, the seismic response characteristics of shield tunnel in soft and hard abrupt strata are studied by using the method of numerical simulation and shaking table test. Firstly, the three-dimensional hybrid model of shield tunnel is established in Abaqus finite element analysis software to simulate the influence of different seismic wave, seismic wave propagation direction, soft and hard interface inclination on tunnel structure and formation dynamic response. The simulation results show that under the action of seismic wave, soft and hard strata have the same law of acceleration response, but the acceleration amplification effect of soft stratum is more obvious, and the stress of tunnel structure will change at the junction of soft and hard strata. When the shear seismic wave is perpendicular to the axis of the tunnel, the abrupt change of the structure stress is the largest, and the change of the interface inclination of the soft and hard strata will also cause the change of the additional principal stress of the tunnel structure, but the influence degree is not significant. The dynamic response of the joint bolt is sensitive to the direction of seismic wave input. When the seismic wave propagates from the tunnel axis to the vertical tunnel axis, the bolt changes from the main shear force to the axial tension. Then, the shaking table model test of shield tunnel is carried out. The experimental results are consistent with the numerical simulation results: for the strata with different physical and mechanical parameters, the acceleration amplification trend of the weaker side of the formation conditions is more obvious. The formation at the same height has the same acceleration response, and the tunnel structure at the interface of soft and hard strata will produce stress concentration phenomenon.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.43;U231.3

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