地震荷载作用下悬索桥隧道式锚碇边坡稳定性分析

发布时间：2018-05-22 11:13

本文选题：悬索桥 + 隧道式锚碇边坡　；参考：《西南交通大学》2017年硕士论文

【摘要】：大跨度悬索桥因自身的优势在高山峡谷地区道路建设中得到了越来越广泛的运用,隧道式锚碇作为悬索桥的一种重要锚固形式,具有受力合理、工程造价低、环境破坏小等特点。悬索桥正常使用期间隧道锚边坡的稳定性问题,特别是地震作用下锚碇边坡稳定性对桥梁结构功能发挥具有极为重要的影响。本文依托四川雅安至康定高速工程泸定大渡河悬索桥隧道锚工程,对不同地震荷载情况下隧道式锚碇边坡稳定性进行了深入分析,主要研究工作如下:(1)基于隧道锚边坡工程地质条件,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有限差分软件模拟分析了在成桥状态1倍设计缆力作用下泸定大渡河悬索桥隧道式锚碇边坡的稳定性,边坡浅表层安全系数为2.45,失稳模式为边坡表层局部将沿着岩土界面(含砾粘土与下伏岩体接触面)向临空面发生滑移;深部岩体的安全系数为3.75,沿锚碇周围局部岩体发生破坏。(2)通过三维数值模拟,分析了 50年超越概率10%地震作用下(E1地震),泸定大渡河悬索桥隧道式锚碇边坡的稳定性,通过点安全系数指标分析表明,边坡整体较为稳定,但表层含砾粘土稳定性较差,存在失稳可能。(3)模拟分析了 50年超越概率2%地震作用下(E2地震),泸定大渡河悬索桥隧道式锚碇边坡的稳定性,边坡整体稳定性相对较差,表层含砾粘土将沿着其与下伏岩体接触面向临空面发生滑移。(4)基于弹性理论Mindlin解和极限平衡理论,采用拟静力法简化地震力,计算了隧道式锚碇在E1、E2地震作用下的稳定性,得出在E1、E2地震作用下,锚碇边坡浅表层的稳定系数分别为1.13和1.06,边坡稳定性理论分析结果与三维数值模拟结果基本一致。本文的研究工作可为高烈度山区大跨度悬索桥隧道式锚碇边坡的抗震稳定性分析与工程设计提供指导与参考,具有重要的工程实际意义。
[Abstract]:The long-span suspension bridge is more and more widely used in the road construction in the high mountain and gorge area because of its own advantages. As an important anchoring form of the suspension bridge, the tunnel Anchorage has reasonable force and low engineering cost. Small environmental damage and other characteristics. During the normal operation of suspension bridge, the stability of tunnel anchor slope, especially the stability of anchor slope under seismic action, has an extremely important influence on the bridge structure function. In this paper, the stability of tunnel Anchorage slope under different earthquake loads is deeply analyzed by relying on the tunnel anchor engineering of Luding Dadu River suspension Bridge in Ya'an to Kangding High Speed Project, Sichuan Province. The main research work is as follows: (1) based on the engineering geological conditions of tunnel anchor slope, a three-dimensional geological model including tunnel Anchorage, underpass highway tunnel, main pier and mountain body is established by using MIDAS-GTS software. The stability of the tunnel Anchorage slope of the Luding Dadu River suspension Bridge under the action of double design cable force in the state of the bridge is simulated by FLAC3D finite difference software. The safety factor of the shallow surface of the slope is 2.45. The model of instability is that the surface of the slope will slip along the interface of the rock and soil (the interface between the gravel clay and the underlying rock mass) to the face of the goaf. The safety factor of the deep rock mass is 3.75, and the local rock mass around the Anchorage is destroyed. The stability of the tunnel Anchorage slope of the suspension bridge of Dadu River in Luding is analyzed by means of three-dimensional numerical simulation under the action of 10% earthquake surpassing probability for 50 years under the action of E 1 earthquake and Luding Dadu River suspension bridge tunnel Anchorage slope. The analysis of the index of point safety coefficient shows that the slope is stable as a whole, but the surface gravelly clay is less stable. The stability of the tunnel Anchorage slope of the Luding Dadu River suspension Bridge under the action of 2% earthquake over 50 years is simulated and analyzed. The overall stability of the slope is relatively poor. On the basis of elastic theory Mindlin solution and limit equilibrium theory, quasi static method is used to simplify seismic force, and the stability of tunnel Anchorage under E1E 2 earthquake is calculated. The stability coefficients of shallow surface layer of Anchorage slope are 1.13 and 1.06 respectively under E _ 1 / E _ 2 earthquake. The results of theoretical analysis of slope stability are in good agreement with those of three-dimensional numerical simulation. The research work in this paper can provide guidance and reference for seismic stability analysis and engineering design of tunnel Anchorage slope of long-span suspension bridge in high intensity mountain area, and has important engineering practical significance.
【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】：U448.25;U441

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