采动区可续建箱型结构承载特性研究

发布时间：2018-01-17 17:11

  本文关键词：采动区可续建箱型结构承载特性研究　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 采动区 箱型结构 数值分析 承载特性 施工方法优化

【摘要】：桥涵是连接交通的重要方式,箱型结构作为抵抗变形的重要结构形式,在采动区显得尤为重要。虽然箱型结构在采动区应用较为广泛,对箱型结构承载能力和抗采动变形研究也较多,但是对箱型结构可续建性研究较少,且多数都是过水箱涵的研究。本文以某矿北区铁路专用线下4#箱型结构为例,对箱型结构的可续建性进行研究。由于该箱型结构续建完成以后总高度为11.6m,普通箱型结构难以满足承载要求,本文参考带扶壁挡土墙设计,提出在结构侧墙外侧设置扶壁的结构形式。本文以无扶壁箱型结构和带扶壁箱型结构两种结构形式为研究对象,运用软件ANSYS分析箱型结构在道砟厚度、倾斜影响下应力变化规律。然后分析带扶壁箱型结构受续建因素影响下承载特性和合理的顶板结构形式,并对箱型结构施工方法进行优化。箱型结构在采动影响下,随着道砟厚度增加,两种结构形式的应力最大值均呈现增大的趋势。两种结构应力值达到最大时约为对应箱型结构受采动影响前的1.20倍~2.50倍之间,但无扶壁箱型结构的应力值约为同条件下带扶壁箱型结构应力值的3.0倍。采动影响除下沉外还有倾斜和曲率,由于该箱型结构的横向尺寸较小,纵向设置了变形缝,因此本文中仅考虑了横断面上均匀倾斜对箱型结构的影响。两种结构形式箱型结构模型应力整体上随斜率的增大,呈现先增大后减小的趋势,一般在斜率为30‰或40‰时应力达到最大。在地表倾斜作用下无扶壁箱型结构应力为带扶壁箱型结构应力的2.30~3.00倍。因此扶壁结构对箱型结构起到很好的保护作用,得出带扶壁箱型结构较无扶壁箱型结构的承载能力有很大提高。带扶壁箱型结构在续建的过程中,还会受到续建次数和建成后顶板和侧墙是否浇筑为一体对箱型结构应力影响。该箱型结构在采动影响下要续建3次,对每次续建后的模型进行数值分析,得到箱型结构随续建次数增加的应力演化规律:箱型结构侧墙的拉应力和X方向的应力在第一次续建后达到最大值,侧墙压应力随着续建次数而逐渐减小;箱型结构底板应力在第一次续建后达到最小,然后随着续建又逐渐增大。对比分析箱型结构顶板和侧墙闭合和不闭合模型,得出箱型结构采用搭板形式对结构较为有利。最后本文就该箱型结构的钢筋连接方法和箱型结构回填土先后顺序进行优化,得到箱型结构钢筋连接采用直螺纹连接方法较为合理,且给出了相应的实施方案;续建完成以后,应先回填箱型结构内侧土体,更有利于保证箱型结构安全。
[Abstract]:Bridge and culvert is an important way to connect traffic. As an important structural form to resist deformation, box structure is especially important in mining area, although box structure is widely used in mining area. There are many researches on the bearing capacity and mining deformation resistance of box structure, but there are few researches on the sustainability of box structure. Most of them are over water box culverts. In this paper, the box structure under the special railway line of North District of a mine is taken as an example. Because the total height of the box structure is 11.6 m, the ordinary box structure can not meet the bearing requirements, this paper refers to the design of retaining wall with supporting wall. In this paper, the box structure without supporting wall and the box structure with supporting wall are taken as the research objects, and the software ANSYS is used to analyze the thickness of the box structure in the ballast. Under the influence of inclination, the stress variation law is analyzed. Then, the bearing characteristics and the reasonable roof structure form of the box structure with buttress are analyzed under the influence of the continuous construction factors. The construction method of box structure is optimized. Under the influence of mining, the box structure increases with the thickness of ballast. When the maximum stress values of the two structures reach the maximum value, it is between 1.20 times and 2.50 times of the corresponding box structure before the mining. However, the stress value of the unsupported box structure is about 3.0 times of that of the box structure with supporting wall under the same conditions. Besides subsidence, mining affects the slope and curvature of the box structure, because the transverse size of the box structure is small. In this paper, only the influence of uniform tilting on the box structure is considered. The stress of the two types of box structure model increases with the slope as a whole. There is a tendency to increase first and then decrease. In general, the stress reaches the maximum when the slope is 30 鈥，

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