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长昆高速铁路桥隧相连高边坡设计参数研究

Study on the Design Parameters of High Slope in Bridge and Tunnel Connecting Section

【作者】 匡经桃

【导师】 吴光;

【作者基本信息】 西南交通大学 , 地质工程, 2013, 硕士

【副题名】In Case of Changkun Passenger Transportation Railway

【摘要】 拟建的长昆铁路客运专线在穿越山区时,出现了许多桥隧相连工程。当前的铁路规范及手册关于桥隧相连地段工程设计形式和边坡设计参数无明确相关规定。本学位论文在总结桥隧相连工程设计特点的基础上,结合工点工程地质条件为长昆铁路雪峰山一号隧道出口边坡和大岩湾一号隧道出口边坡提出了建议性的桥隧相连设计形式。采用有限元数值分析软件MIDAS/GTS软件对不同几何设计参数下的桥隧边坡进行稳定性和动力响应分析。主要研究内容及成果如下:(1)结合桥隧相连工程设计特点和工点工程地质条件,提出雪峰山一号隧道出口处宜采用对接型桥隧相连形式,大岩湾一号隧道出口处宜采用串接型的桥隧相连形式。(2)桥基荷载作用下边坡静力分析结果表明,桩基底的应力变化随着桥基埋深增加而减少。桥基埋深大于20m时,基底等效应力变化比率小于0.1。桥基荷载能否对边坡表层产生影响,主要处决于桥基的水平位置。(3)两处工点不同设计参数下的动力分析结果表明,桥隧边坡表面在列车动荷载作用下的动力响应加速度峰值小于0.05g,动力响应位移峰值小于lmm。(4)雪峰山一号隧道出口采用对接型桥隧相连设计时,桥梁桩基埋深宜取20m,桩基承台外侧至边坡表面距离宜为5m。桥基施工时,边坡纵向开挖的安全坡率为1:0.75,且应采用台阶式的开挖方式,每8m设2m宽平台。隧道洞口侧坡坡率可取1:0.25,洞口仰坡工后采用自然坡度。(5)大岩湾一号隧道出口采用串接型桥隧相连设计时,桥台内置隧道的长度在0~10m范围桥隧边坡是稳定的。桥台内置隧道0~5m时,桥梁荷载对边坡整体稳定的影响较为明显,大于5m以后影响很小。隧道洞口两侧中上部是最易发生破坏的区域。

【Abstract】 There have been many bridge and tunnel connecting section connecting section along the proposed ChangKun passenger line when pass through the mountain areas. TThere are no clear relevant railway specifications and manuals for the design form and slope design parameters of bridges and tunnels connecting section in current. In this study? a proposed design form applied for the outlet slope of Xuefengshan1st tunnel and Dayanwan11st tunnel have been created, based on summarizing the design features of bridge and tunnel connecting section and engineering geological conditions of investigated sites. The slope stability and dynamic response of bridge and tunnel slope in different geometric design parameters are analyzed with the help of MIDAS/GTS software.The main research contents and results are as follows:(1) Based on the design features of bridge and tunnel connecting engineering, the outlet slope of Xuefengshan1st tunnel is suitable for the form of butt-connected bridge and tunnel connecting section, and Dayanwan1st tunnel is suitable for the form of connected in series type.(2) The results of static analysis of slope under bridge loads shows that the change of stress in the bottom of the pile is reducing with the increase of depth of the abutment. When the depth of the abutment is more than20m the change of equivalent stress in the bottom of the pile is less than0.1. Whether the bridge loads has an impact on the slope surface, is mainly determined by the position of the abutment in horizontal.(3) From the dynamic analysis of slopes in the two investigated sites, the dynamic response peak acceleration of the bridge and tunnel slope surface under the train dynamic loads is less than0.05g and the peak displacement is less than1mm.(4) The bridge foundation depth should be taken as20m and the distance between outside of the pile cap and the surface of the slope should be5m when the type of bridge and tunnel connecting in the outlet slope of Xuefengshan1st tunnel is butt-connected. The safety excavation slope in longitudinal direction is1:0.75and it should be taken in the way of making a2m wide platform per8m. The desirable slope of side slope in tunnel portal is1:0.25. After the construction, the slope surface of tunnel entrance should be recovered as natural.(5) The tunnel slope is stable in case the length of abutment built-in tunnel ranges from0to10m when the type of bridge and tunnel connecting in the outlet slope of Dayanwan1st tunnel that connected in series. When the length that the abutment built-in tunnel ranges from0to5m, the bridge load has an obvious impact on the stability of tunnel slope and little impact beyond5m. The upper part of both sides of the tunnel entrance is the area where failure most likely to occur

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