带裂纹重载铁路隧道的力学响应

发布时间：2018-05-14 05:37

本文选题：隧道 + 重载铁路　；参考：《石家庄铁道大学》2016年硕士论文

【摘要】：重载铁路由于其运量大、效率高、成本低等特点,在国民经济的发展中发挥着越来越重要的作用。同时,列车轴重的增加必然会使隧道受到的冲击荷载增大,对隧道结构的承载力造成影响。除此之外,我国多地处于地震灾害的多发地段,地震等自然灾害将会对隧道结构造成巨大的破坏,严重影响行车安全。在隧道的施工和运营过程中,难以避免地会产生衬砌裂纹,在大轴重列车和地震荷载的冲击下,裂纹的存在会使衬砌产生应力集中,加剧隧道的病害,所以对带裂纹重载铁路隧道进行静-动力分析是十分有必要的。本文通过有限元数值模拟的方法,对双线行车带裂纹重载铁路隧道进行了分析。首先采用平面应变模型模拟重载铁路隧道,对隧道结构进行了模态分析,得到了隧道的固有频率和振型。在谐响应分析中,对模型加载随频率变化的节点力和加速度载荷,得到了衬砌在频域内的动力响应。采用正弦波叠加的重载铁路列车荷载和美国实测EL-Centro地震波加速度数据作为荷载,分析了两种荷载作用下衬砌、围岩的位移、应力、速度和加速度的变化规律,比较了两种荷载作用下的动力响应的不同。在对带裂纹重载铁路隧道的分析中,建立拱顶、拱肩、拱腰三个关键位置处存在不同长度裂纹的模型,分别计算得到裂纹尖端处列车和地震作用下的应力强度因子。通过混凝土断裂判据量化分析了不同荷载作用下的衬砌的承载安全系数,并与围岩压力作用下的情况做了对比,以此判断最危险工况和衬砌薄弱位置。结果表明,列车荷载对衬砌仰拱和路基影响比较大,地震荷载对衬砌上部影响比较大。当衬砌存在裂纹时,地震荷载作用下的衬砌承载安全系数较低,列车荷载作用下的衬砌承载安全系数较高。
[Abstract]:Heavy haul railway plays a more and more important role in the development of national economy because of its large capacity, high efficiency and low cost. At the same time, the increase of axle load will inevitably increase the impact load on the tunnel, which will affect the bearing capacity of the tunnel structure. In addition, most of our country is in the earthquake disaster area, earthquake and other natural disasters will cause great damage to the tunnel structure, seriously affect the safety of driving. During the construction and operation of the tunnel, it is difficult to avoid the lining crack. Under the impact of the large axle load train and earthquake load, the existence of the crack will make the lining stress concentration and aggravate the tunnel disease. So it is necessary to do static-dynamic analysis of heavy-haul railway tunnel with crack. In this paper, the finite element numerical simulation method is used to analyze the double track railway tunnel with cracks. Firstly, the plane strain model is used to simulate the heavy haul railway tunnel, and the modal analysis of the tunnel structure is carried out, and the natural frequency and mode shape of the tunnel are obtained. In the harmonic response analysis, the dynamic response of the lining in frequency domain is obtained for the load of the node force and acceleration load varying with the frequency of the model. In this paper, the displacement, stress, velocity and acceleration of lining and surrounding rock under the action of sinusoidal wave superimposed on heavy-haul railway train and the acceleration data of EL-Centro seismic wave measured in the United States are analyzed, and the variation rules of displacement, stress, velocity and acceleration of lining and surrounding rock under two kinds of loads are analyzed. The difference of dynamic response under two kinds of loads is compared. In the analysis of heavy-haul railway tunnel with cracks, a model of crack with different lengths at three key locations of arch, shoulder and waist is established, and the stress intensity factors of train at crack tip and earthquake are calculated respectively. The load-bearing safety factor of lining under different loads is quantitatively analyzed by concrete fracture criterion, and compared with that under surrounding rock pressure, so as to judge the most dangerous working condition and the weak position of lining. The results show that the influence of train load on lining inverted arch and subgrade is greater than seismic load on the upper part of lining. When there are cracks in the lining, the bearing safety factor of the lining under seismic load is lower, and the safety factor of the lining under the train load is higher.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U451

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