边坡上桥梁桩基的受力分析及其在抗滑支护中的应用研究

发布时间：2019-03-03 17:25

【摘要】：中国西部地区经济的快速发展促进交通运输向更方便、更安全、更环保的方向发展，考虑到保护山区生态环境，目前山区高等级公路大多采用隧道或高架桥的形式穿越，桥梁桩基则建设在微坡、缓坡、陡坡、极陡坡的不同形式边坡上。因此，除了承受上部传来的轴向荷载和水平荷载以外，还将承受坡体给予的侧向土压力，边坡段的桥梁桩基处于复杂的地质环境中，，目前针对该类桩基的研究还相对较少，没有一套完整的理论体系，也不能用常规的计算方式来设计和指导。为此，本文采用大型非线性有限元软件ABAQUS模拟，分析不同形式的荷载作用下以及不同荷载的不同组合作用下该类桩基的内力变化和位移变形，并对影响该类桩基受力变形的相关因素进行综合对比分析。 ①首先结合边坡段桥梁桩基特点综合分析其承载机理和受力特性。研究了荷载传递过程，建立了桩基不同特征段的受力微分方程式，并用幂级数解答，得到桩基绕曲变形的求解方法。 ②将边坡根据坡度大小进行分类，引入边坡介质载体这一概念，总结归纳为边坡滑移的链式反应是介质载体的物质体现，用介质载体的链式演化描述滑坡发生过程的滑移特征，基于此，分析滑坡推力及抗力分布形式和计算方法。 ③通过本工程案例中桩土相互作用的三维数值模型计算得到：荷载对桩基的影响程度顺序为：坡顶均布荷载＞桩顶竖向荷载＞桩顶横向荷载。组合荷载作用下，桩身发生挠曲变形，随着桩径的增大，桩身水平位移减小。 ④本案例中陡坡段桩基的变形大于缓坡段桩基的变形，且陡坡段的桩基承载力小于缓坡段桩基的承载力。在斜坡段桩基设计时，其设计桩径或者配筋范围应取决于坡度的急缓程度。 ⑤本案例中岩土弹性模量的增加明显的限制了桩基的变形和减小了桩土的水平应力值。另外，桩周岩体在有桥梁桩基情况下的应力值在规定地基容许范围内。故此，不需要为边坡增加抗滑措施。
[Abstract]:The rapid economic development in the western region of China has promoted the development of transportation in the direction of more convenient, safer and more environmentally friendly. Considering the protection of the ecological environment in mountain areas, most of the high-grade highways in mountain areas now traverse in the form of tunnels or viaducts. The pile foundation of bridge is built on the different slope of micro-slope, gentle slope, steep slope and extremely steep slope. Therefore, in addition to bearing the axial load and horizontal load from the upper part, it will also bear the lateral earth pressure from the slope body. The bridge pile foundation in the slope section is in a complex geological environment, and the research on this kind of pile foundation is still relatively rare at present. There is no complete theoretical system, nor can conventional calculation be used to design and guide. In this paper, the large-scale nonlinear finite element software ABAQUS is used to simulate the internal force and displacement of this kind of pile foundation under different loads and different combinations of different loads. The relative factors affecting the deformation of this kind of pile foundation are comprehensively compared and analyzed. The main contents of this paper are as follows: 1. Firstly, the bearing mechanism and mechanical characteristics of bridge pile foundation in slope section are analyzed comprehensively. In this paper, the load transfer process is studied, and the differential equations of force in different characteristic segments of pile foundation are established, and the method of solving the winding deformation of pile foundation is obtained by using the solution of power series. (2) the slope is classified according to the size of slope, and the concept of medium carrier is introduced. It is concluded that the chain reaction of slope slip is the material embodiment of medium carrier, and the chain evolution of medium carrier is used to describe the slip characteristics of landslide. Based on this, the distribution form and calculation method of landslide thrust and resistance are analyzed. 3 through the calculation of three-dimensional numerical model of pile-soil interaction in this project case, it is found that the order of influence of load on pile foundation is as follows: slope top distributed load > pile top vertical load > pile top transverse load. With the increase of pile diameter, the horizontal displacement of pile body decreases. 4in this case, the deformation of the steep section pile foundation is larger than that of the gentle slope section pile foundation, and the pile foundation bearing capacity of the steep slope section is smaller than that of the gentle slope section pile foundation. In the design of slope section pile foundation, the designed pile diameter or reinforcement range should depend on the degree of rapidity of slope. 5 in this case, the increase of elastic modulus of rock and soil obviously limits the deformation of pile foundation and reduces the horizontal stress value of pile-soil. In addition, the stress value of the surrounding rock mass under the condition of bridge pile foundation is within the allowable range of the specified foundation. Therefore, there is no need to add anti-slip measures for the slope.
【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】：U443.15

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