大吨位悬索桥隧道式锚碇承载性能研究

发布时间：2018-06-08 10:40

本文选题：隧道式锚碇 + 承载力　；参考：《西南交通大学》2015年硕士论文

【摘要】：近些年来,随着我国交通建设的快速发展,大跨径悬索桥已广泛运用于高山峡谷地区道路建设中,隧道式锚碇作为悬索桥的一种重要锚固形式,其承载力及其影响因素是隧道式锚碇工程设计的基础。因此本文依托泸定大渡河悬索桥隧道锚工程,对隧道式锚碇承载力的计算方法和影响因素进行了分析,主要研究工作如下：1)运用MIDAS-GTS软件建立了包含隧道式锚碇、下穿公路隧道、主墩以及山体的三维地质模型,通过FLAC3D有限差分软件模拟了泸定大渡河悬索桥隧道式锚碇在超张拉、极限超张拉、加卸载循环张拉以及围岩长期强度四种典型工况下围岩的变形、锚碇与围岩界面上正应力和摩阻力的分布规律、塑性区分布以及破坏模式,得出泸定大渡河悬索桥隧道式锚碇的极限承载力为7倍的设计缆力,锚碇系统的破坏模式为沿锚碇与围岩界面的剪切破坏,围岩长期强度和加卸载循环张拉工况下锚碇围岩变形均为毫米级,塑性区分布范围较少,锚碇系统承载性能良好。2)通过三维数值分析,得到了当锚碇围岩强度降低为原来的60%、50%、40%时的塑性区分布特征,提出在隧道锚碇围岩强度较低时,有可能发生剖面上下非对称的组合式破坏模式。3)采用极限平衡法分别推导了界面剪切破坏和组合式破坏时的锚碇承载力的近似理论计算公式,其中界面剪切破坏理论计算结果与数值模拟结果误差为2%。利用组合式破坏模式理论公式计算了在围岩强度分别降为原来的100%、70%、60%、50%、40%时锚碇系统承载力和不同缆力作用下系统的安全储备。4)通过三维数值模拟,对隧道式锚碇承载力的影响因素进行了分析,主要包括围岩弹性模量、锚碇轴向倾角、长度及放大角,得出锚碇系统承载力分别随这4个量的增加而呈不同程度的非线性增大的规律；在此基础上考虑锚碇主要影响因素的可改变性对泸定大渡河悬索桥隧道式锚碇原设计的合理性进行了分析,并将原设计优化为：锚碇轴向倾角β=40。,锚碇长度L=50m,锚碇放大角α=-3.6。。本文的研究工作可为大吨位悬索桥隧道式锚碇的设计计算提供指导与参考。
[Abstract]:In recent years, with the rapid development of traffic construction in our country, long-span suspension bridges have been widely used in the road construction in high mountains and canyons. Tunnel Anchorage is an important anchoring form of suspension bridges. Its bearing capacity and its influencing factors are the foundation of tunnel Anchorage engineering design. Therefore, based on the Anchorage project of the Dadu River suspension Bridge, this paper analyzes the calculation method and influencing factors of the bearing capacity of the tunnel Anchorage. The main research work is as follows: 1) using MIDAS-GTS software to establish the tunnel including tunnel Anchorage and underpass highway tunnel. The 3D geological model of main pier and mountain is simulated by FLAC3D finite difference software. The tunnel Anchorage of Dadu River suspension Bridge in Luding is overstretched and the limit is overstretched. The deformation of surrounding rock under four typical conditions of loading and unloading cyclic tension and long-term strength of surrounding rock, the distribution of normal stress and friction at the interface of Anchorage and surrounding rock, the distribution of plastic zone and the failure mode, It is concluded that the ultimate bearing capacity of tunnel Anchorage of Dadu River suspension Bridge in Luding is 7 times of the design cable force, and the failure mode of Anchorage system is shear failure along the interface between Anchorage and surrounding rock. The long-term strength of surrounding rock and loading and unloading cyclic tension condition are all millimeter grade, the distribution range of plastic zone is less, and the load-bearing capacity of Anchorage system is good. 2) through three-dimensional numerical analysis, the deformation of surrounding rock is of millimeter grade, and the distribution range of plastic zone is relatively small. The distribution characteristics of plastic zone are obtained when the strength of the surrounding rock of the Anchorage decreases to 60% and 40% respectively, and it is put forward that when the strength of the surrounding rock of the tunnel Anchorage is low, The combined failure mode. 3) the ultimate equilibrium method is used to deduce the approximate theoretical formulas of the bearing capacity of the Anchorage in the case of interfacial shear failure and combined failure, respectively. The error between the calculated results of interfacial shear failure theory and that of numerical simulation is 2. By using the combined failure mode theory formula, the safety reserve of the Anchorage system under the action of bearing capacity and different cable forces of the Anchorage system has been calculated by three-dimensional numerical simulation. The factors affecting the bearing capacity of tunnel Anchorage are analyzed, including elastic modulus of surrounding rock, axial inclination angle, length and magnification angle of the Anchorage. The results show that the bearing capacity of Anchorage system increases with the increase of these four quantities respectively. On this basis, the rationality of the original design of the tunnel Anchorage of the Luding Dadu River suspension Bridge is analyzed considering the variability of the main influencing factors of the Anchorage, and the original design is optimized as follows: Anchorage axial inclination 尾 40., Anchorage length 50 m, Anchorage magnification angle 伪 -3.6.. The research work in this paper can provide guidance and reference for the design and calculation of tunnel Anchorage of large tonnage suspension bridge.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.25;U443.24

【参考文献】