上软下硬地层地铁隧道与近接桥梁桩基的相互影响分区研究

发布时间：2018-05-21 02:30

本文选题：隧道近接桩基 + 上软下硬地层　；参考：《隧道建设》2017年08期

【摘要】：依托青岛红岛—胶南城际轨道交通工程侧穿多座桥梁的工程实例,采用有限元强度折减法,对上软下硬地层桩基近接影响下的隧道安全系数变化规律进行研究。结果表明:1)水平方向上,随水平净距增大,隧道安全系数增加,至1倍洞径后,安全系数趋于稳定;2)竖直方向上,随埋深增加,隧道安全系数表现为先增大后减小;3)桩基的存在将降低隧道安全系数,增加隧道达到最大安全系数所需的埋深。通过有无桩基对比,对不同相对位置关系下的地铁隧道近接桥梁施工影响程度进行判定:1)总体上竖向的影响范围和影响程度均大于横向;2)当隧道埋深位于桩底以上时,近接施工几乎只对隧道产生影响;3)当隧道埋深位于桩底以下时,近接施工对于隧道和桥梁桩基均有不同程度的影响,当隧道位于桩底时达到最大。通过样条函数插值补全和多重二次曲面拟合的方法,给出影响系数通用分区图,并结合数值模拟下的桩基受力变形特征,得出影响系数0.8对应的等值线为强影响区与弱影响区的分界线,影响系数1的等值线为弱影响区与无影响区的分界线。通过影响分区结论与监测数据对比,验证了研究成果的实用性。
[Abstract]:Based on the engineering example of Qingdao Hongdao-Jiaonan intercity rail transit project, the variation law of tunnel safety factor under the influence of the close connection of pile foundation under soft and hard ground is studied by using the finite element strength reduction method. The results show that in the horizontal direction, with the increase of the net horizontal distance, the safety factor of the tunnel increases, and when the diameter of the tunnel is doubled, the safety factor tends to be stable in the vertical direction and increases with the buried depth. The safety factor of the tunnel is increased first and then decreased. The existence of pile foundation will reduce the safety factor of the tunnel and increase the buried depth required for the tunnel to reach the maximum safety factor. By comparing pile foundation with or without pile foundation, the influence degree of subway tunnel near bridge construction under different relative positions is determined. (1) the overall vertical influence range and influence degree are larger than that of transverse bridge foundation) when the tunnel buried depth is above the pile bottom, When the buried depth of the tunnel is below the pile bottom, the near connection construction has different effects on both the tunnel and the bridge pile foundation, and it reaches the maximum when the tunnel is located at the bottom of the pile. By means of spline function interpolation complement and multiple Quadric surface fitting, the general zoning map of influence coefficient is given, and the deformation characteristics of pile foundation under numerical simulation are combined. It is concluded that the isoline corresponding to the influence coefficient 0.8 is the dividing line between the strong and weak influence areas, and the isoline of the influence coefficient 1 is the dividing line between the weakly affected area and the unaffected area. The practicability of the research results is verified by comparing the results of influence zoning with monitoring data.
【作者单位】：西南交通大学土木工程学院交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金资助项目(51678497,50878185)
【分类号】：U231.3;U443.15;U456.3

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