撞击荷载作用下盾构隧道接头螺栓失效及参数分析

为了研究高速列车脱轨撞击盾构隧道时接头螺栓参数对螺栓失效和管片的影响. 基于ABAQUS有限元软件，建立了盾构隧道管片衬砌分块拼装式模型，利用时速200 km/h列车12.5° 斜向撞击荷载曲线，通过设置接触面单元和具有抗拉、抗剪、抗弯3种刚度组合的连接单元，近似模拟了盾构隧道接缝混凝土接触效应和螺栓连接效应，开展了不同螺栓直径和不同螺栓强度级别下管片接头螺栓的失效研究. 研究结果表明:在列车撞击荷载作用下，接头螺栓主要发生拉伸失效和剪切失效两种失效状态，失效后螺栓拉力和剪力降低为0，并且螺栓失效一般是相对列车行进方向相继出现的；拉伸失效通常出现在被撞块后端纵向螺栓，而被撞块环向螺栓和前端纵向螺栓一般发生剪切失效；各螺栓发生失效的时间随着接头螺栓强度级别的提高或螺栓直径的增大有所延后；不同螺栓参数下被撞块管片位移极大值均在6 cm左右，提高接头螺栓的强度级别和增大螺栓直径，将减小被撞块管片最终位移较大值区域面积以及最终位移极大值的数值，但管片最终位移极大值数值的减幅在10%以内，说明改变螺栓参数无法明显减小管片最终位移. 

Failure and Parametric Analysis of Shield Tunnel Bolts under Impact Load

In order to study the influence of bolt parameters on bolt failures and segments when a derailed high-speed train impacts a shield tunnel, a numerical model of division assembling the segmental lining of a shield tunnel was established using the finite element software ABAQUS. The contact effect of joint concrete and the connecting effect of joint bolts were simulated approximately by the contact element and the connector element, the latter of which characterises the tensile, shear and flexural stiffness. The failure of bolts with different diameters and strengths was investigated using the impact load curve of a train with speed of 200 km/h and oblique angle of 12.5°. The results show that joint bolts mainly underwent tensile failure and shear failure, and the tension and shear forces of the bolt decreased to zero after the failure. Bolt failures generally appeared in succession according to the direction of train travel. Tensile failure usually occurred at the rear longitudinal bolt of the impacted segment, while shear failure usually occurred at the circumferential bolt and the front longitudinal bolt of the impacted segment. The failure time of the bolt was delayed as the bolt strength grade or diameter increased. The maximum displacement of the impacted segments under different bolt parameters was approximately 6 cm. Increasing the strength grade and the diameter of the bolt would reduce the area and the maximum value of the final displacement of the impacted segment. However, the reduction of the maximum value of the final displacement was within 10%, which means that changing the parameters of the bolt cannot significantly reduce the final displacement of the segment.