爆炸地震波作用下盾构隧道动力响应分析

Analysis of dynamic response of shield tunnel to explosion seismic wave

盾构隧道衬砌由于各种类型接头的存在而与整体式衬砌的力学特性存在较大差异。将盾构隧道衬砌结构看作由弹塑性铰链连接的刚性管片组成,考虑围岩介质的黏弹性,提出了爆炸地震波作用下盾构隧道动力分析的简化计算方法。采用该方法对南京地铁盾构段典型横断面进行了动力分析,研究了爆炸地震波入射角度、围岩介质特性及管片厚度对结构受力与变形的影响规律。分析结果表明:波入射角度对盾构隧道有很大影响,斜入射时结构的动力响应要大于垂直入射时结构的动力响应;围岩介质等级越高,围岩对隧道结构的约束越强,隧道的抗爆性能越好;管片厚度的增大会增大结构的内力,合理设置管片厚度有利于提高盾构隧道抗爆性能。

The existence of various types of joints, one of the typical characteristics of prefabricated lining structures, makes the mechanical performance of shield tunnel linings quite different from that of monolithic linings. A simplified calculation method for the dynamic elastoplastic analysis of segment lining subjected to explosion seismic wave is proposed. The lining is composed of a number of rigid arch segments that are interconnected by elastoplastic hinges. The stiffness contribution of joints and the dynamic interaction between the structure and the soil can be properly simulated with the method. As an example, the calculation of the shield section of Nanjing metro subjected to explosion seismic wave is discussed. Meanwhile, the influences of incident wave angle, rock grade and the depth of the segments on dynamic response of tunnel lining are taken into account. The result indicates that the angle of the incident waves plays an important role on the tunnel lining, where the dynamic response to obliquely incident and explosion seismic wave is larger than that to vertically incident and explosion seismic wave. The higher the surrounding rock grades, the better the capacity to resist deformation of liner structure and the better the blast-resistant characteristics of the tunnel will be. The increase of the depth of the segments would lead to notable increase of the internal force, the blast resistant characteristics could be improved by properly setting the depth of the segments.