盾构隧道联络横通道的振动台试验与数值模拟

联络横通道与隧道主体形成的空间交叉结构是隧道抗震的薄弱环节. 为探讨联络横通道采用刚、柔两种连接形式时对盾构隧道地震响应的影响，以相似理论为基础，通过室内土工试验确定了振动台试验中地层和结构相似模型的材料参数及配比，分别建立了振动台试验结构模型和数值分析模型；将第1组试验得到的地层卓越频率15.0 Hz作为其余试验工况和数值计算中地震动频率的输入依据，通过试验和数值计算相结合分析的方法对主隧道与联络横通道的地震响应规律进行了研究. 研究结果表明:结构与相同深度位置地层的加速度响应变化规律基本相同，离地面越近，地层加速度的放大效应越明显；联络横通道采用刚性连接时，其最大应变反应出现在结构的拱顶和两侧拱脚处，而采用柔性连接可较好的降低结构各处的应变反应，且输入地震峰值加速度越大其减弱效果越明显；主隧道横断面上，靠近联络横通道连接处的位置易受其影响而产生应力突变，采用刚性连接时，其受到的影响更大；振动台试验与数值结果规律基本一致，采用刚性连接时，联络横通道对主隧道纵向的影响范围约为3.0倍联络横通道宽度，而采用柔性连接时其影响范围则减小至1.5～2.0倍. 

Shaking Table Test and Numerical Simulation of Shield Tunnel Connecting Cross Passage

The shield tunnel and cross passage forming a spatial cross structure, is a weak link in the seismic resistance. To study the influence of the rigid and flexible connection forms on the shield tunnels in seismic response, the material parameters and proportions of the similar models in the shaking table test were determined by geotechnical tests based on the similarity theory, then the experimental structure and numerical model were established. The 15.0 Hz predominant frequency obtained from the first test was used as the input earthquake frequency in the other test conditions and numerical calculation. The seismic response of the main tunnel and the connecting crossway was studied by combining the model test and numerical calculation. The results show that the acceleration response of the stratum and structure at the same depth is basically the same, and the amplification effect of stratum acceleration is more obvious when closer to the ground. The maximum strain response occurs at the vault and arch foot of the structure when rigid connection is used in the connecting transverse passage. Flexible connection can better reduce the strain response of the structure, and the larger the input peak acceleration is, the more obvious the reduction effect is. On the cross section of the main tunnel, the position near the connection of the connecting cross-passage is susceptible to stress mutation, which is more affected with rigid connection . Shaking table test and numerical results are basically the same, the influence range of the cross channel on the longitudinal direction of the main tunnel is about 3.0 times as wide as that of the cross channel when rigid connection is adopted, while the influence range is reduced to 1.5?2.0 times when flexible connection is adopted.