风环境下山区高速公路桥隧连接段行车安全影响研究

发布时间：2018-03-30 22:13

本文选题：桥隧连接段　切入点：风特性　出处：《长安大学》2014年博士论文

【摘要】：随着城市间联系的不断加强、高速公路的不断建设和国家经济可持续发展的需要，高速公路正逐步向山岭和重丘地区发展。然而随着我国高速公路的不断发展，其行车安全问题也日益突出。此外，桥隧密布、桥隧相连的情况对山区高速公路的交通安全保障也提出了新的挑战。在恶劣气象条件及特殊地理环境下，高速公路上发生交通事故的几率大，同时恶劣气象条件对于事故救援和交通安全管制工作也十分不利。但现阶段关于山区高速公路的研究多集中在对安全问题的阐述及事故原因的定性分析上，对恶劣天气方面的影响主要集中在对雨、雪、雾等不利天气的研究，缺少风对于行车安全的影响研究。汽车在山区高速公路桥隧连接段上行驶时，受风影响较大。当风流经峡谷，会加快流速，同时由于地表的影响，会产生较大的脉动风，平均风夹带着脉动风流动。特别是汽车高速行驶时，在大风作用下的气动侧向力将引起车轮侧偏和非稳态转向，因此峡谷风对行车安全有重要的影响。目前国内外尚缺乏这方面的系统研究，本文试图从桥隧连接段上风特性揭示出对行车安全研究的机理。为研究山区路段峡谷风对桥隧连接段上行车安全的影响，本文选用数值模拟方法对该问题进行计算，利用三维粘性非定常不可压缩N-S方程、k-湍流模型，采用有限体积法建立了峡谷风作用下桥隧连接段周围空气流场的数值计算模型，基于风工程有关理论分析了桥隧连接段上的风特性。在没有车辆行驶时的峡谷风作用下，分析了线路—环境双重作用下基础风环境的流场分布，并且以桥隧连接段为研究对象，试图模拟出其风速变化，为交通安全可行性研究奠定数据基础。同时提出了桥隧连接段上空等效风速和侧风效应系数概念，合理地反映桥面上空的风特性，定量地比较桥隧连接段上风速沿高度和距桥梁中央位置水平距离的不规则变化。应用汽车外流场数值模拟的方法，将行驶在山区高速公路桥隧连接段上的汽车作为研究对象。在假设和简化的基础上，利用GAMBIT软件建立用于数值模拟的三维汽车模型，采用动网格技术和C++编程，根据山区高速公路限速选取适当汽车速度，仿真模拟车辆位于这样的风场环境中，相关影响指标及汽车外流场压力分布的变化情况，定量研究汽车在运动状态下气动力系数，直观的认识流场各处压力分布，分离和涡流的产生及发展。采用较常使用的混凝土护栏，考虑最不利因素的影响，获得了护栏对桥面风环境影响的基本规律。借鉴大跨度桥梁连续风障的设置，针对山区高速公路桥隧连接段其中间风速高，两边风速低的特点，考虑不同尺寸、孔隙率及起止长度，设计适合山区高速公路特点的渐变风障。提出了不同的风障类型，选取减速的作用程度和湍流强度作为评比指标，定量分析其减速效果，确定出最适合山区高速公路桥隧连接段风环境的渐变风障。利用动网格技术仿真模拟渐变风障对车辆气动稳定性及车身周围处压力的影响。利用风洞试验、西汉高速公路现场实测及实验样本数据建立山区高速公路桥隧连接段行车安全模型实例分析。利用模糊理论评价法建立山区高速公路桥隧连接段行车安全改进对比性分析，全面阐述了桥隧连接段影响机动车行车安全的因素，采用层次分析法（AHP）将影响机动车行车安全的因素分为两层，结合层次分析法（AHP）和人工神经网络法对两层的各因素进行建模，，借助MATLAB-simulink等软件实现模型求解。通过分析验证数值模拟的准确性、添加护栏和阶梯型渐变风障后的有效性以及评价方法的适用性。
[Abstract]:With the continuous development of inter - city connection , the continuous construction of the expressway and the sustainable development of the national economy , the highway is gradually developing towards the mountains and the heavy hills . However , with the development of the expressway in China , the traffic safety problem of the highway is increasingly prominent . In addition , the influence of the wind on the traffic safety is greatly influenced by the adverse weather conditions such as rain , snow and fog .

In order to study the effect of valley wind on bridge tunnel connection in mountain road section , the numerical simulation method is used to calculate the air flow field around the bridge tunnel under the action of three - dimensional viscous unsteady incompressible N - S equation and k - turbulence model .

On the basis of assumption and simplification , a three - dimensional automobile model for numerical simulation is established by the use of the dynamic grid technique and C ++ programming . The simulation simulation vehicle is located in such a wind farm environment . The simulation simulation vehicle is located in such a wind farm environment . The simulation simulation vehicle is located in such a wind farm environment . The simulation simulation vehicle is located in such a wind farm environment . The simulation simulation vehicle is located in such a wind farm environment . The simulation simulation vehicle is located in such a wind farm environment . The simulation simulation vehicle is located in such a wind farm environment . The dynamic coefficient of the vehicle is quantitatively studied , and the pressure distribution , separation and vortex generation and development in the flow field are recognized intuitively .

Based on the influence of the most unfavorable factors , the basic law of the impact of the barrier on the wind environment of the bridge deck is obtained by the use of the commonly used concrete barrier . For reference to the characteristics of high wind speed and low wind speed of the bridge and tunnel junction of the mountain highway , different types of wind obstacles are taken into account , the effect degree of deceleration and the turbulence intensity are taken into consideration to quantitatively analyze the deceleration effect , and the influence of the gradient wind barrier on the aerodynamic stability of the vehicle and the pressure around the vehicle body is determined by using the dynamic grid technology simulation .

In this paper , an example of driving safety model of bridge and tunnel connecting section in mountain highway is established by means of wind tunnel test , on - site measurement and experimental sample data of Xihan highway . The factors influencing the safety of motor vehicle driving safety are analyzed by fuzzy theory evaluation method . The factors influencing the safety of motor vehicle driving safety are analyzed comprehensively by using analytic hierarchy process ( AHP ) and artificial neural network method . The accuracy of numerical simulation is verified , the effectiveness of the barrier and step type gradient wind barrier is added and the applicability of the evaluation method is applied .

【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U492.84;U458

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