断层粘滑及近场地震动作用下公路隧道结构力学行为研究

发布时间：2018-04-14 00:26

本文选题：震源断层 + 粘滑作用　；参考：《西南交通大学》2017年硕士论文

【摘要】：我国境内具有复杂、活跃的板内构造,本地区地震活动大多与板内的活动断层有关,其触发机制多为地壳内部震源断层的粘滑行为。震源断层发震时会造成地表岩土层沿断层面产生脆性破裂形成地震断层,长久以往近场区域还会伴有若干断层、断层破碎带等特殊地质构造;另外,震害调研以及地震工程学研究成果反应近断层地震动具有速度脉冲、竖向分量效应等特征,其对结构物的影响明显区别于远场地震动。随着各地建设规划的实施,难免有地处震源断层场地区域的隧道工程,因此对于近场区域的隧道结构而言有不可小觑的安全隐患,本文便着手断层粘滑作用下跨地震断层公路隧道的破坏机理和近场地震动作用下穿越断层破碎带公路隧道的动力响应两方面开展了如下工作:(1)以龙门山断裂为背景,基于速率弱化摩擦本构定义震源断层非线性接触关系,以模拟断层粘滑时刻的破裂行为,并利用Burgers粘弹性本构定义地壳岩石圈的流变属性,通过施加板块的挤压(拉伸)速率进行逆断层(正断层)粘滑过程的数值模拟,同时对比计算了多种板块运动速率下断层产生粘滑作用的差异。其次,建立了水平面内的走滑断层数值计算模型,采用同样的方法模拟走滑断层的粘滑过程。最终,得到三种形式断层粘滑作用时的关键参数特征曲线,作为下一步研究的基础。(2)建立一正向穿越倾角60°地震断层的公路隧道三维有限元模型,将(1)中获得的断层粘滑时刻上下盘的相对位移时程施加到三维计算模型中,通过扩展有限元理论获得不同地层条件的逆断层、正断层、走滑断层粘滑作用下衬砌开裂的力学行为和破坏机理。(3)建立赋存于近断层场地、穿越断层破碎带隧道结构三维有限元模型,定义混凝土结构的弹塑性本构,对比相同峰值加速度的共4条近场、非近场地震波作用下隧道结构的动力响应差异,以评价近断层地震动的速度脉冲对穿越断层破碎带隧道的动力效应;保持水平向输入集集地震波,定义竖向与水平向峰值向加速度比λ,对竖向地震分量作用下穿越断层破碎带隧道结构的动力响应特征进行分析。
[Abstract]:There are complex and active intraplate structures in China. The seismic activities in this area are mostly related to the active faults in the plate, and the triggering mechanism is mostly the visco-slip behavior of the focal faults in the crust.When the source fault occurs, it will result in brittle rupture along the fault plane of the surface rock and soil layer to form an earthquake fault. In the past, there will also be some special geological structures, such as faults, fault fracture zones, etc. In the near field in the past,Seismic damage investigation and seismic engineering research results show that near-fault seismic response has the characteristics of velocity pulse and vertical component effect, and its influence on structure is obviously different from that of far-field ground motion.With the implementation of local construction planning, it is inevitable that there is a tunnel project located in the area of the focal fault site, so there is a potential safety hazard for the tunnel structure in the near-field area.In this paper, the failure mechanism of the cross-seismic highway tunnel under the action of slip and the dynamic response of the highway tunnel under near-field ground motion through the broken fault zone are discussed as follows: 1) taking the Longmenshan fault as the background,Based on the velocity weakening friction constitutive equation, the nonlinear contact relationship of the focal fault is defined to simulate the rupture behavior at the time of viscosity and slip of the fault, and the rheological properties of the crustal lithosphere are defined by using the Burgers viscoelastic constitutive equation.The viscous slip process of the reverse fault (normal fault) is simulated by applying the compression (tensile) rate of the plate, and the difference of the sticking-slip effect of the fault under various plate motion rates is compared and calculated.Secondly, the numerical model of strike-slip fault in horizontal plane is established, and the same method is used to simulate the stick-slip process of strike-slip fault.Finally, the key parameter characteristic curves of three types of fault stick-slip action are obtained. As the basis of further study, a 3-D finite element model of highway tunnel with forward crossing of 60 掳seismic fault is established.The relative displacement time history of the upper and lower displacements of the upper and lower displacements obtained from the slip time of the fault is applied to the three-dimensional computational model, and the reverse faults and normal faults with different formation conditions are obtained by extending the finite element theory.The mechanical behavior and failure mechanism of lining cracking under the action of stick-slip of strike-slip fault. (3) the three-dimensional finite element model of tunnel structure through fault fracture zone is established, and the elastic-plastic constitutive model of concrete structure is defined.The dynamic response of tunnel structure under the action of non-near-field seismic wave is compared with that of four near-field with the same peak acceleration to evaluate the dynamic effect of velocity pulse of near-fault ground earthquake on the tunnel through fault broken zone.The vertical and horizontal peak acceleration ratio 位 is defined and the dynamic response characteristics of the tunnel structure through the fault broken zone under the action of the vertical seismic component are analyzed by preserving the horizontal input collection of seismic waves and defining the ratio of vertical to horizontal peak acceleration.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451

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