抗滑桩在动静力作用下的工作性能研究

发布时间：2018-03-17 20:36

本文选题：ANSYS　切入点：抗滑桩　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国经济的高速发展,越来越多的工程建设在山区开展,滑坡问题日益凸显。尤其是5.12汶川大地震后,大量的滑坡发生,造成了巨大的人员伤亡和财产损失。作为滑坡治理中最常用的支挡手段,抗滑桩能够有效地提高边坡的稳定性。但是目前关于抗滑桩设计方面相关研究并不多见,由于抗滑桩设计理论欠缺,与实际工程存在较大出入。鉴于此,本文结合ANSYS有限元分析软件对抗滑桩在静力和动力作用下的工作机制进行了分析,分析了抗滑桩各设计要素对抗滑桩桩顶位移、桩底应力和承载力的影响,对完善抗滑桩设计理论及方法具有重要意义。本文主要成果和结论如下：(1)总结抗滑桩在静动荷载作用下的理论分析方法和经验公式,寻找分析影响抗滑桩结构稳定的因素。(2)利用／ANSYS有限元计算软件对抗滑桩进行数值模拟分析,在模型中,用SOLID65单元来模拟混凝土,用LINK8单元来模拟钢筋,采用分离式配筋方法建立钢筋混凝土模型。(3)分析抗滑桩在不同荷载分布模式作用下的变形,抗滑桩在集中荷载作用下桩顶位移最大,矩形均布荷载和梯形荷载相差较小。在抗滑桩设计中,应根据工程实际情况选择荷载分布方式,若选择不当,将会造成抗滑桩施工困难,增加投资,反之则会造成设计失败,工程失效。(4)分析抗滑桩的桩截面、弹性模量、惯性矩的变化对抗滑桩桩顶位移、桩底应力和桩身承载力的影响,通过各设计要素与桩顶的位移关系曲线可知,钢筋的等级和桩的配筋率对抗滑桩的桩顶位移影响相对较弱,而桩身采用的混凝土等级、桩截面和长细比对改变桩顶位移和承载力影响更大。(5)抗滑桩各设计参数存在一个理论界限值,超过该界限值以后,提高抗滑桩的设计参数对抗滑桩变形影响作用较小,并且会带来施工困难和造价提高,尤其是钢筋等级、配筋率、混凝土强度取较保守值时,对桩顶位移的作用已无显著效果。(6)抗滑桩在正弦周期荷载作用下,荷载加载方式对抗滑桩桩顶位移影响较大,低频率的动荷载对抗滑桩桩项位移有显著影响。因此抗滑桩设计中,要充分考虑动荷载对抗滑桩的影响,防止抗滑桩因动荷载而发生破坏导致治理工程失效。
[Abstract]:With the rapid development of China's economy, more and more engineering projects have been carried out in mountainous areas, and landslide problems have become increasingly prominent. Especially after the 5.12 Wenchuan earthquake, a large number of landslides occurred. As the most commonly used supporting method in landslide control, anti-slide pile can effectively improve the stability of slope. However, there are few researches on the design of anti-slide pile at present. Due to the lack of design theory of anti-slide pile, it is quite different from practical engineering. In view of this, this paper analyzes the working mechanism of anti-slide pile under static and dynamic action with ANSYS finite element analysis software. The effects of various design elements of anti-slide pile on the top displacement, pile bottom stress and bearing capacity of sliding pile are analyzed. It is of great significance to perfect the design theory and method of anti-slide pile. The main achievements and conclusions of this paper are as follows: 1) summarize the theoretical analysis method and empirical formula of anti-slide pile under static and dynamic load. To find out the factors that affect the stability of anti-slide pile structure. (2) numerical simulation of anti-slide pile is carried out by using the software of FEA. In the model, SOLID65 element is used to simulate concrete, and LINK8 element is used to simulate steel bar, in the model, the concrete is simulated by SOLID65 element, and the reinforcement is simulated by LINK8 element. The separated reinforcement method is used to establish the reinforced concrete model. 3) to analyze the deformation of the anti-slide pile under different load distribution modes, and the maximum displacement of the pile top under concentrated load is obtained. The difference between rectangular uniform load and trapezoidal load is small. In the design of anti-slide pile, the load distribution mode should be selected according to the actual situation of the project. If the selection is not proper, it will cause difficulties in the construction of anti-slide pile and increase the investment, otherwise, it will cause the design failure. The variation of pile cross section, elastic modulus and moment of inertia of anti-slide pile is analyzed to resist the influence of pile top displacement, pile bottom stress and pile body bearing capacity. The grade of reinforcing bar and the ratio of reinforcement of pile against the displacement of pile top of sliding pile are relatively weak, but the grade of concrete used in pile body is relatively weak. The influence of pile cross-section and slenderness ratio on pile top displacement and bearing capacity is greater. 5) there is a theoretical limit value for each design parameter of anti-slide pile. After the limit value is exceeded, the effect of increasing the design parameters of anti-slide pile against sliding pile deformation is less. In particular, when the grade of reinforcement, the ratio of reinforcement and the strength of concrete are conservatively taken, there is no significant effect on the displacement of pile top. (6) under the action of sinusoidal cyclic load, the anti-slide pile has no significant effect on the displacement of the pile top, especially when the reinforcement grade, the ratio of reinforcement and the strength of concrete are taken as conservative values. The load loading mode has a great influence on the top displacement of sliding pile, and the low frequency dynamic load has a significant effect on the displacement of sliding pile. Therefore, in the design of anti-slide pile, the influence of dynamic load against sliding pile should be fully taken into account. To prevent the failure of anti-slide pile caused by dynamic load.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU473.1

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