低等级公路新型支挡结构物的配筋设计优化

发布时间：2018-05-16 20:50

本文选题：加筋格宾挡土墙 + 设计方法　；参考：《重庆交通大学》2014年硕士论文

【摘要】：加筋格宾挡土墙自于其自身的优点，正被各行业所接受和推广，在低等级公路方面则需要降低该新型支挡结构的造价以推广其使用。对挡墙的配筋设计优化是降低造价的一重要手段，不但能降低挡墙造价，而且能加深对挡墙工作原理、性能的掌握。在实际工程上，加筋格宾挡墙的配筋优化一般都是在极限平衡原理的基础上，采用均匀间距、等长、同刚度筋材的布设方式，这样的优化方法没有很好的考虑在不同加筋模式下土体与筋材相互作用的特点。通过考虑土体与筋材相互作用下产生的协调变形、受力和位移等情况能很好的贴近工程实际，因此本文通过有限元数值分析方法来研究加筋格宾挡墙在各种不同加筋模式下所展现的侧向位移规律和筋材受力的规律，从而为挡墙设计提供配筋优化指导，这对加筋格宾挡土墙在低等级公路的推广应用有很大的促进作用，具有十分重要意义。本文通过有限元软件Plaxis建立大尺寸挡墙模型来进行研究分析，分析了加筋格宾挡土墙内部受力和位移特点。通过建立不同种类的加筋模式和不同面板形式的挡墙模型进行分组研究，重点分析研究了挡墙的侧向位移和筋材受荷所存在的规律。主要研究成果有：1、在挡墙的侧向位移方面，土体内摩擦角变化所带来的影响最大，略大于土体的弹性模量，而内聚力的影响最小，在挡墙稳定性方面，内摩擦角的影响最大，远大于影响其次的内聚力和最小的弹性模量；2、加筋量相同的情况下，交替加筋比分组加筋更能有效的控制侧向位移，刚度交替加筋的侧向位移形状与均匀加筋一样，只是量稍微有些增加，进一步缩短小刚度筋材的长度可以很好的减少加筋量，且对挡墙的侧向位移影响很小；3、三种及三种以上不同刚度筋材混合加筋时，将刚度大的筋材布设在挡墙侧向位移最大的区域能有效的控制挡墙变形；4、各种加筋模式下直立式面板挡墙侧向位移最大，，其次是倾斜式与直立式相结合的挡墙，最小的是倾斜式面板挡墙；5、加筋间距不变、降低部分筋材刚度要比筋材刚度不变或增大、增大加筋间距的方案更加有效控制侧向变形；6、相同刚度筋材均匀加筋的话，筋材拉力大小和分布不受筋材刚度大小的影响，但筋材拉力会随着加筋间距的增加而增大，且面板形式对筋材荷载的大小和分布情况影响很大；7、交替加筋采用刚度相差较大的筋材时，刚度大的筋材作为主筋材将承担更多的土体侧压力，主加筋层的间距会影响挡墙的侧向位移和筋材的最大拉力值，进而还会影响挡墙的局部变形；8、长度和刚度同时交替加筋时，刚度交替带来的影响比长度交替更加显著，大刚度筋材所承担的拉力比小刚度筋材大，大刚度筋材起着主加筋层的作用。
[Abstract]:Reinforced Gobin retaining wall is being accepted and popularized by various industries because of its own advantages. In the aspect of low-grade highway, the cost of the new retaining structure should be reduced in order to popularize its use. The optimization of reinforcement design is an important means to reduce the cost of retaining wall. It can not only reduce the cost of retaining wall, but also deepen the grasp of the working principle and performance of retaining wall. In practical engineering, the reinforcement optimization of reinforced Gobin retaining wall is usually based on the principle of limit equilibrium, the uniform spacing, equal length, and the same stiffness of reinforcement are adopted. This optimization method does not take into account the interaction between soil and reinforcement in different reinforcement modes. By considering the coordinated deformation, force and displacement caused by the interaction between soil and steel, it can be very close to the engineering practice. In this paper, finite element numerical analysis method is used to study the lateral displacement law and the stress law of reinforced material in different reinforcement modes, so as to provide optimization guidance for the design of retaining wall. This will promote the application of reinforced Gobin retaining wall in low-grade highway greatly and has very important significance. In this paper, the finite element software Plaxis is used to build a large size retaining wall model to study and analyze the internal force and displacement characteristics of reinforced Gebin retaining wall. By establishing different types of reinforced model and different panel type of retaining wall model, the paper analyzes and studies the law of lateral displacement of retaining wall and the law of stiffened material subjected to load. The main research results are as follows: in the aspect of lateral displacement of retaining wall, the variation of internal friction angle of soil is the biggest, slightly larger than the elastic modulus of soil, while cohesion is the least, and the influence of angle of internal friction is the most in the aspect of stability of retaining wall. In the case of the same amount of reinforcement, the lateral displacement can be controlled more effectively by alternating reinforcement than by grouping reinforcement, and the shape of lateral displacement of alternating reinforcement is the same as that of uniform reinforcement. But the quantity is slightly increased, further shortening the length of small stiffness bars can reduce the reinforcement amount very well, and the influence on lateral displacement of retaining wall is very small, when three or more kinds of stiffened steel bars with different stiffness are mixed, The deformation of retaining wall can be effectively controlled by placing stiffened steel bars in the area with the largest lateral displacement of the retaining wall, and the lateral displacement of the vertical slab retaining wall is the largest under various reinforced modes, and the second is the retaining wall with the combination of the inclined type and the vertical type. The smallest one is inclined panel retaining wall (5), the spacing of reinforcement is invariable, the stiffness of some reinforcement is reduced or increased than the stiffness of reinforcement, and the scheme of increasing reinforcement spacing is more effective in controlling lateral deformation (6%). If the reinforcement is uniformly reinforced with the same stiffness, The tensile force and distribution of the steel bar are not affected by the stiffness of the steel bar, but the tensile force of the steel bar increases with the increase of the reinforcement spacing. The form of slabs has a great influence on the load and distribution of steel bars. When the stiffeners with different stiffness are used alternately, the stiffeners with large stiffness will bear more lateral pressure of soil. The spacing of the main stiffened layer will affect the lateral displacement of the retaining wall and the maximum tensile force of the steel bar, and then affect the local deformation of the retaining wall. When the length and stiffness of the retaining wall are alternately stiffened at the same time, the influence of the alternate stiffness is more significant than that of the alternating length. The tensile force of the steel bar with large stiffness is larger than that of the steel bar with small stiffness, and the steel bar with large stiffness acts as the main reinforcement layer.
【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】：U417.1

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