發(fā)布時間：2018-04-24 17:47

  本文選題：公路路橋過渡段 + 剛性楔形搭板�。� 參考：《北京交通大學(xué)》2017年碩士論文

【摘要】：由于路基和橋臺的不均勻沉降和剛度差異,在路橋過渡段常發(fā)生橋頭跳車現(xiàn)象,將對舒適性、安全性、結(jié)構(gòu)和車輛的耐久性造成不利影響。設(shè)置搭板是一種比較常見的改善方法,而普通橋頭搭板易出現(xiàn)搭板折斷和二次跳車等多種病害,剛性楔形搭板則能體現(xiàn)搭板的優(yōu)勢且能克服以上的病害。本文以剛性楔形搭板為研究對象,采用了數(shù)值模擬方法,建立了車輛-過渡段三維耦合動力學(xué)模型,選取了車體豎向振動加速度、動荷載系數(shù)、前后車輪豎向位移差和搭板兩端錯臺高度作為評價指標(biāo),分析了剛性楔形搭板不同上表面坡度、最大厚度、彈性模量和長度取值對車輛行駛平順性的影響,研究了以不同車速經(jīng)過過渡段時平順性的差異,探究了車速較快時剛性楔形搭板對橋頭跳車的改善作用,構(gòu)造不同路面隨機不平順,提出了隨機不平順條件下搭板對車輛行駛平順性的改善效果。通過以上內(nèi)容研究,得到了如下結(jié)論:(1)設(shè)置楔形搭板可以明顯地減小車體豎向加速度;楔形搭板上表面坡度、長度的增加,可以減小搭板遠(yuǎn)離橋臺一端的錯臺高度;楔形搭板彈性模量和最大厚度的增加,可以減小搭板靠近橋臺一端的錯臺高度;楔形搭板最大厚度的增加,有利于減小前后輪豎向最大位移差和車輪最大動荷載系數(shù);同時搭板長度不宜小于車輛長度。在本文工程條件下,建議選擇上表面坡度10～20‰;搭板長度不小于7m;最大厚度0.30～0.40m;彈性模量選取C80混凝土。(2)在過渡段條件一定的情況下,車速越快,車輛的動力響應(yīng)增長得越快;速度在10m/s(36km/h)以內(nèi)時,速度對車輛動力響應(yīng)的影響不大,而速度由20m/s(72km/h)增加到30m/s(108km/h)時,車輛的最大豎向加速度增加了 104.6%,前輪最大動荷載系數(shù)增加了 55.9%,后輪最大動荷載系數(shù)增加了 57.3%,前后輪最大豎向位移差增加了 25%。因此當(dāng)各種措施無法明顯減小車輛動力學(xué)響應(yīng)時建議限制車速在10m/s(36km/h)以內(nèi),;隨著速度的增大,搭板對加速度的改善效果減弱。(3)在假設(shè)設(shè)置搭板不能緩解路面不平順程度的條件下,傳統(tǒng)搭板和剛性楔形搭板在改善隨機不平順影響下車輛的動力響應(yīng)的效果非常微弱,搭板的設(shè)置對前后輪豎向位移差沒有任何改善作用。
[Abstract]:Due to the uneven settlement and stiffness difference between subgrade and abutment, bridge-head jump often occurs in the transition section of road and bridge, which will adversely affect the comfort, safety, structure and durability of the vehicle. Setting slabs is a common improvement method, but common bridgehead abutments are prone to many kinds of diseases, such as lap slab breakage and secondary jump. Rigid wedge-shaped slab can reflect the advantages of lapping slab and overcome the above diseases. In this paper, a three-dimensional coupling dynamic model of vehicle-transition section is established by using the numerical simulation method, and the vertical vibration acceleration and dynamic load coefficient of the vehicle body are selected. The vertical displacement difference of the front and rear wheels and the height of the staggered platform at both ends of the slabs are used as the evaluation indexes. The effects of different upper surface slope, maximum thickness, modulus of elasticity and length on the ride comfort of the rigid wedge-shaped slab are analyzed. This paper studies the difference of ride comfort when passing through the transition section with different speed, probes into the improvement effect of rigid wedge-shaped slab on bridgehead jumping when the speed is fast, and constructs different road surface random irregularity. The improvement effect of slabs on vehicle ride comfort under the condition of random irregularity is put forward. Through the above research, the following conclusions are obtained: (1) the vertical acceleration of the car body can be obviously reduced by setting the wedge-shaped lap plate, and the height of the staggered platform at the end of the bridge abutment can be reduced with the increase of the slope and length of the upper surface of the wedge lap plate; The increase of elastic modulus and maximum thickness of wedge-shaped slab can reduce the height of staggered platform near one end of abutment, and the increase of maximum thickness of wedge-shaped slab is helpful to reduce the maximum vertical displacement difference of front and rear wheel and the maximum dynamic load coefficient of wheel. At the same time, the length of the slab should not be less than the length of the vehicle Under the engineering condition of this paper, it is suggested to choose the upper surface slope of 10 ~ 20 鈥，

本文編號：1797638