【作者】 王鹏；

【导师】 何沛祥； 陶常法；

【作者基本信息】 合肥工业大学 ， 结构工程， 2020， 硕士

【摘要】 随着经济与科技的不断发展,各种各样的隧道不断被建设出来,从而使两地间距离缩短,减少时间与经济上的成本。虽然有诸多好处,并且从技术上来说也日渐成熟,但是仍然存在一系列安全方面问题,譬如火灾。隧道由于内部空间狭长这一特性,一旦车辆发生事故造成火灾,其产生的热量与烟气势必会对人员以及隧道结构带来巨大的伤害。为了评估隧道结构防火性能,对于隧道火灾的研究是十分有必要的。本文通过双火源耦合实验、变弧度弯曲隧道火灾实验以及有限元分析等方法对火焰燃烧时的高度、燃料质量损失速率、隧道顶棚纵向中心轴线温度分布和隧道的热——力响应进行了研究,主要内容如下:本文利用双火源实验台,对矩形燃烧器尺寸、燃烧器纵横比和燃烧器间距离对于双火源火焰长度的影响进行了一系列的实验。数据分析中,以特征长度表征燃烧器尺寸和燃烧器之间的距离,并作为量纲长度对火焰长度进行无量纲化处理,最终得到了双火源火焰高度的长度模型。为了研究弯曲隧道中火灾特性,本文采用缩尺寸实验方法,设计了可变弧度的隧道实验台,改变弯曲角度、火源高度、油盘尺寸以及火源位置,研究燃料的质量损失速率和顶棚温度变化。结果表明燃料的质量损失速率与弯曲角度是负相关,与火源高度、油盘尺寸均是正相关。隧道弯曲角度的变化,不会影响顶棚最高温度,四种弯曲角度隧道中所得到的最高温度,均满足同一个模型。在火源正上方的一侧,顶棚纵向中心轴线温度符合指数衰减这一规律,同一弯曲弧度隧道中,温度分布满足同一个指数模型,但是,在不同弯曲弧度的隧道中,其温度分布模型不同,这表明弯曲弧度的改变会影响顶棚的温度场。本文选取0°隧道为代表,采用仿真模拟的方法,利用得到的中心轴线温度分布模型,分别在无温度荷载和有温度荷载条件下进行力学分析。结果表明,在23MW的火源产生的温度场中,隧道衬砌的变形会受到一定程度的抑制。更多还原

【Abstract】 With the continuous development of economy and science and technology,various kinds of tunnels have been built continuously,thus shortening the distance between the two places and reducing the cost of time and economy.Despite the benefits and increasingly sophisticated technology,there are still a number of safety issues,such as fire.Due to the characteristics of tunnel-narrow and long,once the vehicle accident causes a fire,the heat and smoke generated by it is bound to bring great harm to the personnel and tunnel structure.In order to evaluate the fire resistance performance of the tunnel structure,it is necessary to make research about the tunnel fire.Double fire experiments,curved tunnel fire experiments and finite element analysis method are used in this thesis,to investigate the flame height of the coupling flame,the fuel mass loss rate,the temperature distribution of tunnel ceiling longitudinal center axis and thermal-mechanical response of the tunnel.The main contents are as follows:In this thesis,by changing the rectangular burner size,aspect ratio of the burner and the distance between the two burners in double fire experiments respectively,the change of the flame height of the coupling flame is studied.In the data analysis,the characteristic length D,which represents the distance between the burner and the burner size,is proposed.And the length of the coupling flame is dimensionless treated by the characteristic length.The model of the coupling flame height is obtained,finally.In order to study the fire characteristics in curved tunnels,a series of reduced-scale tunnel experiments are conducted,with different bending angles,different heights of the burner,different sizes of the burner,and different positions.The changes of the mass loss rate and the temperature distribution of tunnel ceiling longitudinal center axis are analyzed respectively.And the results show that the mass loss rate of fuel is negatively correlated with the bending angle and positively correlated with the height of the burner and the size of burner.As far as the maximum temperature of the tunnel ceiling is concerned,the change of the bending angle does not make a difference,that is,the maximum temperature obtained in the four curved tunnels satisfies the same model.On the side directly above the fire source,the temperature of the longitudinal central axis of the ceiling conforms to the law of exponential attenuation.In the same curved tunnel,the temperature distribution satisfies the same exponential model.However,in the tunnel with different bending angle,the temperature distribution model is different,which indicates that the change of bending angle will affect the temperature field of the ceiling.In this thesis,0° tunnel is selected as the representative.And the temperature distribution of the central axis is used to conduct mechanical analysis under the conditions of no temperature load and temperature load respectively.The results show that the deformation of tunnel lining will be restrained to some extent in the temperature field generated by 23 MW ignition source.更多还原