沟埋式涵洞的土拱效应及土压力研究

发布时间：2018-06-05 17:01

  本文选题：涵洞 + ANSYS　； 参考：《太原理工大学》2014年硕士论文

【摘要】：涵洞广泛的使用于铁路、公路、水利、能源、市政和冶金等部门,它更是铁路工程与公路工程的重要组成部分。研究涵洞土压力变化规律对涵洞的施工建设有着重要的价值和意义。目前我国关于涵洞土压力的研究并不完善,不同方法所计算的数值差别很大,于是导致施工中建筑材料的浪费,甚至有可能因不合理引发工程事故,严重的影响到我国涵洞的施工建设。随着我国经济的快速发展,涵洞的建设在工程施工中出现的越来越频繁,确定涵洞土压力的研究迫在眉睫。 本文利用ANSYS有限元软件,对沟埋式箱涵的土压力以及填土内部土拱效应进行模拟研究,分析了填土土拱效应与土压力在不同条件下的变化规律,并且利用文献中的模拟试验所得结果与ANSYS模拟分析的数值对比分析。本文主要研究成果如下： 1.沟埋式箱涵(沟槽宽度为五倍的涵洞宽度)的垂直土压力的最小值在涵顶的中心位置,随着远离涵顶中心,其垂直土压力值逐渐增大,直至距涵洞的中轴线0.45D的位置时垂直土压力达到最大值。侧向土压力的最大值在距离涵顶0.2D的位置附近,侧向土压力系数随着填土高度的增加而减小。 2.在不考虑涵洞对土体的作用时,土体内部小主应力拱的形状为一条悬链线,通过摩尔应力圆,分析土拱任意微分单元受力,根据其边界条件得到沟埋式方涵在不考虑涵洞作用时小主应力拱的曲线方程,当摩擦角和摩擦系数增大,小主应力拱的曲率逐渐越小。根据小主应力拱曲线,进一步求出侧土压力系数,土体竖向平均应力和水平侧土压力。 3.以等沉面和涵项平面为界限,将土拱的分布划分为三个区域。 在区域Ⅰ内,随着沟槽宽度的增大,土拱曲率逐渐减小；随着内摩擦角的增大,土拱曲率逐渐减小；随着沟槽与土体的摩擦系数的增大,土拱曲率逐渐减小；随着粘聚力的增大,土拱曲率逐渐增大。 在区域Ⅱ内,随着沟槽宽度的增大,土拱曲率逐渐减小；随着内摩擦角的增大,土拱曲率逐渐减小；随着沟槽与土体的摩擦系数的增大,土拱曲率逐渐减小；随着粘聚力的增大,土拱曲率逐渐增大。 在区域Ⅲ内,随着沟槽宽度的不断增加,内土柱内部的土拱效应明显增强,土拱的曲率逐渐增大,在内土柱两侧的土体中,土拱的曲率随着沟槽的宽度增加而不断的减小；随着土体的内摩擦角增大,内土柱内部的土拱曲率逐渐增大,而在内土柱两侧的土体内,土拱曲率随着内摩擦角增大而减小；随着沟槽与土体的摩擦系数增大,内土柱内部的土拱的曲率并无明显变化,而内土柱外侧土体内的土拱曲率随着摩擦系数的增大而减小；随着粘聚力的增大,内土柱内部土拱的曲率和内土柱外侧土体内部的土拱曲率皆逐渐增大。 4.涵洞项板受压产生形变,由挠度引起内土柱内部出现土拱效应。随着涵洞顶板厚度的增大,涵顶土体内的土拱曲率逐渐减小。
[Abstract]:Culverts are widely used in railway, highway, water conservancy, energy, municipal and metallurgical sectors. It is of great value and significance to study the variation of soil pressure in culvert construction. At present, the research on soil pressure of culverts in China is not perfect, and the numerical value calculated by different methods is very different, which leads to the waste of construction materials in construction, and may even lead to engineering accidents because of unreasonable causes. Seriously affect the construction of culverts in China. With the rapid development of China's economy, the construction of culverts appears more and more frequently in engineering construction, so it is urgent to determine the earth pressure of culverts. In this paper, ANSYS finite element software is used to simulate the earth pressure and the soil arch effect of the box culvert, and the variation law of the soil arch effect and the earth pressure under different conditions are analyzed. The numerical results obtained from the simulation experiments in the literature are compared with those of the ANSYS simulation analysis. The main research results of this paper are as follows: 1. The minimum value of vertical earth pressure of the furrow buried box culvert (culvert width of five times the width of the culvert) is at the center of the culvert top. With the distance from the culvert top center, the vertical earth pressure value increases gradually. The vertical earth pressure reaches the maximum when it is 0.45D from the central axis of culvert. The maximum value of lateral earth pressure is about 0.2D from the culvert top, and the lateral earth pressure coefficient decreases with the increase of filling height. 2. Without considering the effect of culvert on soil, the shape of small principal stress arch in soil is a catenary line. According to the boundary conditions, the curve equation of the small principal stress arch is obtained when the culvert is not considered. When the friction angle and friction coefficient increase, the curvature of the small principal stress arch decreases gradually. According to the curve of small principal stress arch, the coefficient of lateral soil pressure, the vertical average stress of soil and the horizontal lateral earth pressure are obtained. 3. The distribution of soil arch is divided into three regions by the boundary of equal-settlement plane and culvert plane. In region I, the curvature of soil arch decreases with the increase of groove width, the curvature of soil arch decreases with the increase of internal friction angle, the curvature of soil arch decreases with the increase of friction coefficient between groove and soil. With the increase of cohesive force, the curvature of soil arch increases gradually. In region 鈪，

本文编号：1982763