库仑土压力的力学机制研究及其工程应用

发布时间：2018-03-10 07:38

本文选题：挡土墙　切入点：库仑土压力理论　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：库仑土压力理论至今仍是计算土压力的主要方法之一,并在工程中广泛应用。然而,随着土木工程科学的发展和对土木工程安全性要求的提高,传统的土压力理论已不能满足土压力问题的设计计算,对土压力理论的研究一直是土木工程中的一个研究热点。根据目前库仑土压力的研究现状,本文从基本的力学方法和力学现象出发,对库仑土压力的计算方法进行了探讨和研究。本文完成的研究工作如下：1.通过分析库仑土压力的墙后土楔体的受力特点,特别是深入研究了土楔体与墙的作用力关系,对库仑土压力理论给出了一些修正。(1)认为土楔体和挡土墙之间的作用力(也即定义的土压力),并非一定要达到极限状态,所以不能确定土压力的作用方向,但土压力的作用方向必须在其允许的角度范围之内。所以,本文研究认为库仑主动土压力为作用方向角度变化范围内的最大值,库仑被动土压力为作用方向角度变化范围内的最小值。(2)对于墙后土楔体,本文认为,墙体和土楔体是两个不同物体,土楔体的形成是因为土中产生有潜在破裂面,而原库仑土压力理论要求墙体与土之间也达到临界状态是不必要的。墙体对土楔体的作用力(即土压力)实质就是相当于一物(墙)施加于另一物(土楔体)的力,即使土楔体滑动了,两物之间也并非要滑动。(3)本文推导了修正的主动土压力计算公式,给出了被动土压力的近似计算方案。通过例题证明本文的计算结果与原库仑理论有明显不同。2.考虑传统库仑土压力并不满足力距平衡,本文开展了严格静力平衡方法的库仑土压力计算方法的研究。(1)考虑墙后土楔体的静力矩平衡条件下,推导了土压力的解析公式。(2)通过建立不同类型的挡土墙模型,用Matlab编程对推导的表达式数值求解,得到挡土墙在不同的滑动面坡角时对应的土压力大小,在土压力的方向取值范围之内找到最大土压力值,其对应的角度即为滑动面的位置。(3)根据分析的结果得到填土面坡角这一参数对土压力计算结果的影响很大。3.采用有限元数值方法对工程实例和算例进行模拟分析,并和传统库仑理论、修正方法和严格静力平衡法计算所得出的结果进行比较。结果表明,本文修正方法和严格静力平衡法计算结果合理,说明了本文研究工作的理论与工程意义。
[Abstract]:Coulomb earth pressure theory is still one of the main methods to calculate earth pressure and is widely used in engineering. However, with the development of civil engineering science and the improvement of safety requirements of civil engineering, The traditional earth pressure theory can not satisfy the design and calculation of the earth pressure problem. The research on the earth pressure theory has been a hot research topic in civil engineering. According to the current research situation of Coulomb earth pressure, In this paper, the calculation method of Coulomb earth pressure is discussed and studied based on the basic mechanical methods and mechanical phenomena. The research work accomplished in this paper is as follows: 1. By analyzing the mechanical characteristics of the soil wedge behind the wall of Coulomb earth pressure, In particular, the relationship between the earth wedge and the wall is deeply studied, and some amendments to the Coulomb earth pressure theory are given. It is concluded that the interaction force between the soil wedge and the retaining wall (that is, the defined earth pressure) does not have to reach the limit state. Therefore, the direction of action of earth pressure cannot be determined, but the direction of action of earth pressure must be within the allowable angle range. For the soil wedge behind the wall, the wall and the soil wedge are two different objects, and the soil wedge is formed because of the potential rupture surface in the soil. It is unnecessary for the original Coulomb earth pressure theory to require a critical state between the wall and the soil. The wall force on the soil wedge is essentially equivalent to the force applied by one object (wall) to another (soil wedge). Even if the soil wedge slips, it is not necessary to slip between the two objects.) in this paper, a modified formula for calculating active earth pressure is derived. The approximate calculation scheme of passive earth pressure is given. It is proved by examples that the calculated results in this paper are obviously different from the original Coulomb theory. 2. Considering that the traditional Coulomb earth pressure does not satisfy the balance of force distance, In this paper, the Coulomb earth pressure calculation method of strict static equilibrium method is studied. 1) considering the static moment equilibrium condition of the soil wedge behind the wall, the analytical formula of earth pressure is derived. The derived expressions are solved numerically by Matlab programming, and the corresponding earth pressure of the retaining wall at different slope angles of sliding surface is obtained, and the maximum earth pressure is found within the range of the direction of the earth pressure. The corresponding angle is the position of the sliding surface.) according to the analysis results, the slope angle of the fill surface has a great influence on the calculation results of the earth pressure. The finite element numerical method is used to simulate the engineering examples and the calculation examples. The results obtained by the traditional Coulomb theory, correction method and strict static equilibrium method are compared. The results show that the results of the modified method and the strict static equilibrium method are reasonable. The theoretical and engineering significance of the research work in this paper is explained.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU432

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