重力式U型高橋臺結(jié)構受力的數(shù)值模擬分析研究
發(fā)布時間：2019-06-10 20:47
【摘要】：重力式U型橋臺因其取材方便且施工簡單等優(yōu)點在橋梁工程中備受青睞,現(xiàn)行的U型橋臺標準圖的高度在8米以下,寬度在12米之內(nèi),難以滿足實際設計需要。通過對已有與在建橋臺的調(diào)查表明,填土高度大于8米或?qū)挾却笥?5米的橋臺多有開裂現(xiàn)象,橋臺整體性被破壞。本文通過有限元分析模擬以及現(xiàn)場工程測試,對不同高度、寬度、側(cè)墻長度、內(nèi)墻坡度以及不同工況下的重力式U型高橋臺臺身應變-應力規(guī)律進行研究,尋求重力式U型高橋臺的受力特點,提出有利于高橋臺預防或緩解開裂病害及使得結(jié)構受力更為穩(wěn)定的設計方法。具體研究內(nèi)容與成果如下： ①以收集分析大量資料為基礎,分析現(xiàn)有重力式U型高橋臺在在建、運營過程中出現(xiàn)的開裂現(xiàn)象及其原因�？偨Y(jié)得出,開裂原因主要是：一、高橋臺側(cè)、前墻截面寬度很難滿足規(guī)范要求,現(xiàn)行規(guī)范有較大的局限性。二、現(xiàn)行土壓力計算簡化為平面計算,不能真實反映土側(cè)壓力對墻身的影響。 ②分析了不同高度下臺身應力-應變分布規(guī)律及其隨高度增加的變化規(guī)律。臺身豎向壓應力呈上小下大的分布規(guī)律,且隨高度增加,壓應力整體增大,最大壓應力出現(xiàn)在前、側(cè)墻墻踵處。臺身橫向應力呈上拉下壓的分布規(guī)律,前、側(cè)墻交匯處為拉應力集中區(qū)域；橋臺較為高聳時,自身相對穩(wěn)定,寬高比接近1的橋臺在荷載作用下其臺身頂部墻壁較薄的受拉區(qū)是應力較大,容易破壞的位置,在設計或加固中應重點考慮。 ③分析了不同側(cè)墻長度下臺身應力-應變分布規(guī)律,側(cè)墻長度主要影響側(cè)墻橫向應力分布。側(cè)墻長度過小時,臺內(nèi)填土體積較小,較難維持橋臺穩(wěn)定；過長時墻頂容易因橫向拉應力過大而造成開裂。前、側(cè)墻交匯處是拉應力集中區(qū)域,是容易產(chǎn)生病害的薄弱位置。 ④分析了不同前墻寬度下臺身應力-應變分布規(guī)律,高窄橋臺臺內(nèi)填土體積較小,填土重量較難維持橋臺穩(wěn)定；寬大橋臺內(nèi)大量填土對側(cè)、前墻產(chǎn)生了較大的水平壓力,造成墻身變形。前墻寬度的增大可對側(cè)墻上部的橫向受拉變形起到緩解作用,但同時也使前墻上部的受拉區(qū)域以及橫向拉應力增大,通過有限元數(shù)值模擬可以看到,前墻寬度主要影響前墻橫向受拉應力分布,對于側(cè)墻的影響不如前墻明顯。 ⑤分析了不同內(nèi)墻坡度下臺身應力-應變分布規(guī)律。臺身橫向應力隨坡度增大而增加,在臺背填土填筑階段,坡度變化產(chǎn)生的應力差距較明顯；而在成橋、運營階段坡度對臺身橫向拉應力影響的明顯程度降低。 ⑥分析了不同工況下臺身應力-應變分布規(guī)律。工況對臺身的豎向及橫向應力分布均有明顯的影響,尤其是對前墻豎向應力和側(cè)墻橫向應力的分布。重力式橋臺的前墻作為主要承重結(jié)構承受豎向壓力,在設計施工過程中需注意臺身偏心受壓發(fā)生傾覆。特別是在橋臺形態(tài)高窄時,需保證臺內(nèi)填土有足夠的質(zhì)量,以維持臺身平衡。在運營過程中,橋臺高度越大,側(cè)墻越長,底部和前墻對側(cè)墻自由端的約束作用越小,后者變形愈發(fā)加劇,針對以上結(jié)論提出施工中應注意的事項。 ⑦對現(xiàn)場依托工程進行測試,與模擬得出的臺身應力-應變分布規(guī)律相互印證。
[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
【學位授予單位】：重慶交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U441;U443.21
本文編號：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
【學位授予單位】：重慶交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U441;U443.21
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