崩坡积区桥墩台的稳定与处治技术研究

发布时间：2018-01-15 05:04

本文关键词：崩坡积区桥墩台的稳定与处治技术研究　出处：《重庆交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：位于堆积体斜坡上的桥梁基桩在堆积体变形后会产生相应的作用力，目前斜坡和桥梁基桩相互作用机理以及如何布置抗滑桩来提高基桩和斜坡的稳定性研究较少，因此本文以渝湘高速公路棕树凼大桥滑坡处治工程为依托，运用PFC2D软件对以下几方面进行了研究并得出了相应结论：首先，通过室内直剪试验对堆积体物理力学性质进行研究，得出了松散堆积体抗剪参数c、取值范围，其中为25.67o～32.53o，c为5.13kPa～32.29kpa，并在原位直剪试验的基础上推导了弹性模量的求解方法；运用PFC软件对堆积体斜坡稳定性进行研究，发现加载和介质抗剪性能偏低引起的松散堆积体的破坏模式不同。一般材料抗剪性能偏低，，堆积体斜坡一般从坡角处发生小变形，而逐渐出现拉裂面，随着变形的加大，整体发生破坏。而松散堆积体在重力荷载加载作用下受力表现为上部受拉、中部剪切、底部受压；在斜坡和基桩相互作用机理方面，分析了不同荷载类型对基桩工作特性的影响，并用PFC软件分析了基于斜坡不同的推力形式、大小和作用点时基桩的内力的变化情况，坡体推力的改变对位于堆积体桥梁基桩的工作性状影响非常显著，推力4500kN时基桩位移为8.3cm、弯矩值为3500kN.m、剪力值为-800kN，推力为零时基桩位移为1.70cm、弯矩为970kN.m、剪力值为-90kN。位移增幅达388%，弯矩增幅达260%，剪力增幅达788%；最后研究了基桩和抗滑桩的相对位置对斜坡和基桩稳定性的影响，得出抗滑桩置于桩前斜坡的稳定性整体优于抗滑桩布置于桩后，同时抗剪参数偏低引起的滑坡，抗滑桩建议设置于基桩后面，加载引起的滑坡抗滑桩建议设置于基桩前，抗滑桩靠前布置时，基桩内力和变形均小于抗滑桩靠后布置时基桩的内力和变形。所以从基桩的稳定性考虑，建议抗滑桩布置于基桩前。本文研究所获得的结论，对位于松散堆积体斜坡的桥梁基桩稳定性评价、斜坡和基桩相互作用机理以及如何布置抗滑桩来提高基桩和斜坡的安全性，具有一定的理论意义，并在设计上具有一定的参考价值。
[Abstract]:The pile of bridge foundation on the slope of accumulation body will produce the corresponding force after the deformation of the accumulation body. At present, there are few researches on the interaction mechanism of slope and bridge foundation pile and how to arrange anti-slide pile to improve the stability of foundation pile and slope. Therefore, this paper relies on the landslide treatment project of Changshutang Bridge on Yu-Hunan Expressway. The following aspects are studied by using PFC2D software and the corresponding conclusions are drawn: Firstly, the physical and mechanical properties of the bulk are studied through the direct shear test in laboratory, and the shear parameters c and the range of values are obtained, which are 25.67o- 32.53o. C is 5.13kPa32.29kpa. based on in-situ direct shear test, the solution method of elastic modulus is deduced. Using PFC software to study the slope stability of the deposit body, it is found that the failure mode of the loose deposit is different from that caused by the low shear resistance of the medium, and the shear resistance of the general material is low. Generally, a small deformation occurs from the slope corner, and a tensile crack surface appears gradually. With the increase of deformation, the whole body is destroyed, while the loosely accumulated body is subjected to the upper tensile force under the action of gravity load. Middle shear, bottom compression; In the aspect of interaction mechanism between slope and foundation pile, the influence of different load types on the working characteristics of foundation pile is analyzed, and the different thrust forms based on slope are analyzed by PFC software. The change of the internal force of the foundation pile at the size and the point of application, the change of the thrust of the slope body has a significant effect on the working behavior of the pile foundation in the accumulated bridge, and the displacement of the foundation pile is 8.3cm when the thrust is 4500kN. The bending moment value is 3500kN.m, the shear force value is -800kN, the thrust is 00:00 foundation pile displacement is 1.70 cm, the bending moment is 970 kN.m. The shear value is -90 kN.The increment of displacement is 388, the increase of bending moment is 260 and the increase of shearing is 788. Finally, the influence of the relative position of the foundation pile and the anti-slide pile on the stability of the slope and the foundation pile is studied. It is concluded that the stability of the anti-slide pile placed on the slope in front of the pile is better than that of the anti-slide pile placed behind the pile. At the same time, the landslide caused by low shear parameters, anti-slide pile is proposed to be set behind the foundation pile, load caused by the landslide anti-slide pile suggested in front of the pile, anti-slide pile before the arrangement. The internal force and deformation of the foundation pile are smaller than that of the foundation pile when the anti-slide pile is arranged behind the pile, so considering the stability of the foundation pile, it is suggested that the anti-slide pile be arranged in front of the foundation pile. The conclusion obtained in this paper is the evaluation of the stability of the bridge foundation pile located in the loose accumulated slope, the interaction mechanism between the slope and the foundation pile, and how to arrange the anti-slide pile to improve the safety of the foundation pile and the slope. It has certain theoretical significance, and has certain reference value in the design.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.1

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