重力式U型高桥台结构受力的数值模拟分析研究
发布时间：2019-06-10 20:47
【摘要】：重力式U型桥台因其取材方便且施工简单等优点在桥梁工程中备受青睐,现行的U型桥台标准图的高度在8米以下,宽度在12米之内,难以满足实际设计需要。通过对已有与在建桥台的调查表明,填土高度大于8米或宽度大于15米的桥台多有开裂现象,桥台整体性被破坏。本文通过有限元分析模拟以及现场工程测试,对不同高度、宽度、侧墙长度、内墙坡度以及不同工况下的重力式U型高桥台台身应变-应力规律进行研究,寻求重力式U型高桥台的受力特点,提出有利于高桥台预防或缓解开裂病害及使得结构受力更为稳定的设计方法。具体研究内容与成果如下： ①以收集分析大量资料为基础,分析现有重力式U型高桥台在在建、运营过程中出现的开裂现象及其原因。总结得出,开裂原因主要是：一、高桥台侧、前墙截面宽度很难满足规范要求,现行规范有较大的局限性。二、现行土压力计算简化为平面计算,不能真实反映土侧压力对墙身的影响。 ②分析了不同高度下台身应力-应变分布规律及其随高度增加的变化规律。台身竖向压应力呈上小下大的分布规律,且随高度增加,压应力整体增大,最大压应力出现在前、侧墙墙踵处。台身横向应力呈上拉下压的分布规律,前、侧墙交汇处为拉应力集中区域；桥台较为高耸时,自身相对稳定,宽高比接近1的桥台在荷载作用下其台身顶部墙壁较薄的受拉区是应力较大,容易破坏的位置,在设计或加固中应重点考虑。 ③分析了不同侧墙长度下台身应力-应变分布规律,侧墙长度主要影响侧墙横向应力分布。侧墙长度过小时,台内填土体积较小,较难维持桥台稳定；过长时墙顶容易因横向拉应力过大而造成开裂。前、侧墙交汇处是拉应力集中区域,是容易产生病害的薄弱位置。 ④分析了不同前墙宽度下台身应力-应变分布规律,高窄桥台台内填土体积较小,填土重量较难维持桥台稳定；宽大桥台内大量填土对侧、前墙产生了较大的水平压力,造成墙身变形。前墙宽度的增大可对侧墙上部的横向受拉变形起到缓解作用,但同时也使前墙上部的受拉区域以及横向拉应力增大,通过有限元数值模拟可以看到,前墙宽度主要影响前墙横向受拉应力分布,对于侧墙的影响不如前墙明显。 ⑤分析了不同内墙坡度下台身应力-应变分布规律。台身横向应力随坡度增大而增加,在台背填土填筑阶段,坡度变化产生的应力差距较明显；而在成桥、运营阶段坡度对台身横向拉应力影响的明显程度降低。 ⑥分析了不同工况下台身应力-应变分布规律。工况对台身的竖向及横向应力分布均有明显的影响,尤其是对前墙竖向应力和侧墙横向应力的分布。重力式桥台的前墙作为主要承重结构承受竖向压力,在设计施工过程中需注意台身偏心受压发生倾覆。特别是在桥台形态高窄时,需保证台内填土有足够的质量,以维持台身平衡。在运营过程中,桥台高度越大,侧墙越长,底部和前墙对侧墙自由端的约束作用越小,后者变形愈发加剧,针对以上结论提出施工中应注意的事项。 ⑦对现场依托工程进行测试,与模拟得出的台身应力-应变分布规律相互印证。
[Abstract]:The gravity type U-type abutment is popular in the bridge engineering because of its convenient materials and simple construction. The current U-shaped abutment standard is in the height of 8 meters or less and the width is within 12 meters. It is difficult to meet the actual design requirements. Through investigation of the existing and existing bridge, the abutment integrity of the abutment is broken when the height of the fill is greater than 8 m or the abutment with a width of more than 15 m is cracked. Based on the finite element analysis and on-site engineering test, the strain-stress law of the gravity-type U-shaped high abutment in different height, width, side wall length, inner wall slope and different working conditions is studied, and the stress characteristics of the gravity type U-shaped high abutment are obtained. The design method for preventing or relieving the cracking of high abutment and making the structure more stable is put forward. The specific research contents and achievements are as follows: Based on the collection and analysis of a large amount of data, the cracking of the existing gravity U-shaped high abutment in the process of construction and operation and its former are analyzed. The reasons for cracking are:1. The width of the cross section of the front wall is difficult to meet the requirements of the specification, and the current specification has a great limitation. 2. The current earth pressure calculation is simplified to the plane calculation, and the shadow of the earth side pressure on the wall body cannot be truly reflected In this paper, the stress-strain distribution law and the change of stress-strain distribution at different heights are analyzed. The vertical compressive stress of the platform body is a large distribution rule, and the compressive stress is increased as a whole with the increase of the height. The maximum compressive stress appears in the front and the side walls. The lateral stress of the platform body is the distribution rule of the pull-down depression, and the junction of the front and the side walls is the tensile stress concentration area; when the abutment is high, the self-relative stability and the aspect ratio of the abutment close to the 1 are relatively thin in the top wall of the platform body under the load effect, The position of the unit shall be heavy in the design or reinforcement. The stress-strain distribution law of the length of different side walls is analyzed. The length of the side wall mainly affects the lateral side of the side wall. The stress distribution is distributed. The length of the side wall is too small, the filling volume in the platform is small, the stability of the abutment is difficult to be maintained, and the top of the wall is easy to be excessively stressed by the transverse pulling stress when the length of the wall is too long. The intersection of the side wall and the side wall is the concentrated area of the tensile stress, which is easy to produce the disease. The stress-strain distribution law of the body stress-strain distribution of different front wall width is analyzed, and the filling volume of the high-narrow bridge abutment is relatively small, and the filling weight is difficult to maintain the stability of the abutment, and a large horizontal pressure is generated on the opposite side and the front wall of the large bridge table. The width of the front wall can relieve the lateral tension deformation of the side wall part, but at the same time, the tension area and the transverse tensile stress of the front wall part can be increased, and the front wall width is mainly influenced by the front wall width by the numerical simulation of the finite element. To be distributed to the tensile stress, for the shadow of the side wall It's not as obvious as the front wall. I've analyzed the fall of different interior walls. The stress-strain distribution law. The lateral stress of the platform is increased with the increase of the slope, and the stress difference generated by the change of the slope is more obvious in the filling stage of the back filling of the stage, and the transverse tensile stress of the platform body at the slope of the bridge and the operation stage The effect of different working conditions is analyzed. The stress-strain distribution of the platform body has a remarkable influence on the vertical and lateral stress distribution of the table body, especially the vertical of the front wall. The distribution of transverse stress of the force and side wall. The front wall of the gravity type abutment bears the vertical pressure as the main bearing structure, and needs to be noted during the design and construction process. The eccentric compression of the platform body is overthrown. In particular, when the form of the abutment is high, it is necessary to ensure that the filling in the platform is sufficient The larger the abutment height, the longer the side wall, the smaller the restraining effect of the free end of the side wall at the bottom and the front wall, the smaller the deformation of the latter, aiming at the above conclusion. The items to be paid attention to in the construction shall be put forward. The site shall be tested on the site depending on the project, and the platform body obtained by the simulation shall be
【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】：U441;U443.21
本文编号：2496721
[Abstract]:The gravity type U-type abutment is popular in the bridge engineering because of its convenient materials and simple construction. The current U-shaped abutment standard is in the height of 8 meters or less and the width is within 12 meters. It is difficult to meet the actual design requirements. Through investigation of the existing and existing bridge, the abutment integrity of the abutment is broken when the height of the fill is greater than 8 m or the abutment with a width of more than 15 m is cracked. Based on the finite element analysis and on-site engineering test, the strain-stress law of the gravity-type U-shaped high abutment in different height, width, side wall length, inner wall slope and different working conditions is studied, and the stress characteristics of the gravity type U-shaped high abutment are obtained. The design method for preventing or relieving the cracking of high abutment and making the structure more stable is put forward. The specific research contents and achievements are as follows: Based on the collection and analysis of a large amount of data, the cracking of the existing gravity U-shaped high abutment in the process of construction and operation and its former are analyzed. The reasons for cracking are:1. The width of the cross section of the front wall is difficult to meet the requirements of the specification, and the current specification has a great limitation. 2. The current earth pressure calculation is simplified to the plane calculation, and the shadow of the earth side pressure on the wall body cannot be truly reflected In this paper, the stress-strain distribution law and the change of stress-strain distribution at different heights are analyzed. The vertical compressive stress of the platform body is a large distribution rule, and the compressive stress is increased as a whole with the increase of the height. The maximum compressive stress appears in the front and the side walls. The lateral stress of the platform body is the distribution rule of the pull-down depression, and the junction of the front and the side walls is the tensile stress concentration area; when the abutment is high, the self-relative stability and the aspect ratio of the abutment close to the 1 are relatively thin in the top wall of the platform body under the load effect, The position of the unit shall be heavy in the design or reinforcement. The stress-strain distribution law of the length of different side walls is analyzed. The length of the side wall mainly affects the lateral side of the side wall. The stress distribution is distributed. The length of the side wall is too small, the filling volume in the platform is small, the stability of the abutment is difficult to be maintained, and the top of the wall is easy to be excessively stressed by the transverse pulling stress when the length of the wall is too long. The intersection of the side wall and the side wall is the concentrated area of the tensile stress, which is easy to produce the disease. The stress-strain distribution law of the body stress-strain distribution of different front wall width is analyzed, and the filling volume of the high-narrow bridge abutment is relatively small, and the filling weight is difficult to maintain the stability of the abutment, and a large horizontal pressure is generated on the opposite side and the front wall of the large bridge table. The width of the front wall can relieve the lateral tension deformation of the side wall part, but at the same time, the tension area and the transverse tensile stress of the front wall part can be increased, and the front wall width is mainly influenced by the front wall width by the numerical simulation of the finite element. To be distributed to the tensile stress, for the shadow of the side wall It's not as obvious as the front wall. I've analyzed the fall of different interior walls. The stress-strain distribution law. The lateral stress of the platform is increased with the increase of the slope, and the stress difference generated by the change of the slope is more obvious in the filling stage of the back filling of the stage, and the transverse tensile stress of the platform body at the slope of the bridge and the operation stage The effect of different working conditions is analyzed. The stress-strain distribution of the platform body has a remarkable influence on the vertical and lateral stress distribution of the table body, especially the vertical of the front wall. The distribution of transverse stress of the force and side wall. The front wall of the gravity type abutment bears the vertical pressure as the main bearing structure, and needs to be noted during the design and construction process. The eccentric compression of the platform body is overthrown. In particular, when the form of the abutment is high, it is necessary to ensure that the filling in the platform is sufficient The larger the abutment height, the longer the side wall, the smaller the restraining effect of the free end of the side wall at the bottom and the front wall, the smaller the deformation of the latter, aiming at the above conclusion. The items to be paid attention to in the construction shall be put forward. The site shall be tested on the site depending on the project, and the platform body obtained by the simulation shall be
【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】：U441;U443.21
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