【作者】 赵曙光；

【导师】 田力；

【作者基本信息】 天津大学 ， 结构工程， 2009， 硕士

【摘要】 地下隧道内爆炸,附近地表上的建筑物将产生一定的响应,并且产生一定的破坏作用。本文针对连续梁桥、桁架桥、斜拉桥等三类不同桥型结构在遭受邻近地下隧道内爆炸作用下的动力响应进行了系统研究。主要研究工作及成果如下:(1)应用ABAQUS软件建立了适用于爆炸荷载下的地基土、混凝土材料以及钢材的本构模型;应用LS-DYNA软件建立包括炸药、空气和隧道壁在内的三维模型,计算得到隧道内壁的超压荷载;选用混凝土塑性损伤模型和Drucker-Prager准则来分别建立混凝土材料和土体介质的本构模型;引入三维一致粘弹性边界单元处理半无限地基;采用主从接触面模型模拟土-结构相互作用;针对连续梁桥、桁架桥、斜拉桥等三类不同桥型结构在不同位置爆炸荷载作用下的响应、在同种爆炸荷载作用下桥梁上不同位置的响应以及在不同水深下桥梁结构上的响应,本文进行了对比分析。对于连续梁桥在无水状态下的工况,本文通过在LS-DYNA软件中的模拟,与在ABAQUS软件中模拟的结果进行比较,从而验证本文方法的有效性和合理性。(2)连续梁桥结构在邻近地下隧道内爆炸荷载作用下,爆炸荷载位置以及桥体上的不同位置是决定爆炸响应的主要因素。当改变水深时,发现主要影响到连续梁桥的应力峰值大小,对于位移峰值和加速度峰值的影响比较小。总体上,改变水深时,连续梁桥上所取节点的响应随水深增加而逐渐减小。即在枯水期时响应最大,正常水位期时响应大小次之,汛期时最小。(3)桁架桥结构在邻近地下隧道内爆炸荷载作用下,桁架桥上节点的主要变形方向是沿横向。且总体规律是越靠近爆炸源,响应越大。当改变水深时,桁架桥上所取节点的响应遵循的规律比较复杂。(4)斜拉桥结构在邻近地下隧道内爆炸荷载作用下,当爆炸荷载作用在隧道中部时,桥体上所取节点响应基本上是对称的。且当爆炸荷载作用在隧道中部时,桥跨中处节点的应力峰值基本上是最大的,当爆炸荷载作用到隧道两端处时,桥跨中处节点的应力峰值最小。当改变水深时,斜拉桥上所取的节点的响应所遵循的规律比较复杂。拉索内力峰值总体上符合随水深的增加而减小的规律。更多还原

【Abstract】 The explosion in the underground tunnel may cause the dynamic response and even destruction of various types of adjacent surface structures.In this paper, the dynamic response of three types of briges such as continuous girder bridge,truss bridge and cable-stayed bridge, subjected to explosive loading in the underground tunnel is investigated numerically. The main research work and conclusions are drawn as follows:(1) The constitutive model of soil, concrete and steel applicable to blast load is established with the ABAQUS software; LS-DYNA software is used to build thethree-dimensional model including the explosives, air and the tunnel wall in order tocalculate the over-pressure loads on tunnel walls. Concrete damaged plasticity model and Drucker-Prager criteria are applied for simulating concrete materials and soil medium, respectively. The stiffness and damping matrixes of 3D consistent artificial boundary is introduced to deal with the semi-infinite soil ground. The master-slave intersection model is used to simulate soil-structure interaction. In this paper, the dynamic response of three types of briges such as continuous girder bridge,truss bridge and cable-stayed bridge,is compared in three different situations including different explosive positions,different part of the bridge and different water depths.For continuous girder bridge without water,the result of LS-DYNA software is compared with that of ABAQUS software.And It can be proved that the method is proper.(2) When the continuous girder bridge is subjected to an explosive loading in an adjacent underground tunnel,the position of the explosion as well as different part of the bridge are the main factors of the results.When water depth increases,the respose of the nod on the continuous girder bridge decreases gradually.That is to say,the response is maximum in the dry season,second in the normal water level period and minimum in the flood season.(3) When the truss bridge is subjected to an explosive loading in an adjacent underground tunnel,the main direction of deformation is on the Z axis.The respose increases when it is nearer with the explosion source. When water depth changes,the respose of the bridge structure becomes more complicated.(4) When the cable-stayed bridge is subjected to an explosive loading in an adjacent underground tunnel,with the explosion effecting on the middle of the structure,the response is symmetrical.The peak stress of the nod in the middle of the structure is maximum while the peak stresses of the nod in the two ends areminimum. When water depth changes, the respose of the bridge structure becomes more complicated.The cable’s internal force peak is decreasing on the whole when water depth increases.更多还原