货运列车振动对隧道基底围岩的影响规律研究

发布时间：2018-04-16 11:08

本文选题：现场测试 + 基底围岩　；参考：《北京交通大学》2017年硕士论文

【摘要】：我国山岭隧道病害现象严重,其中尤以隧道基底病害为甚。据调查,列车荷载的往复振动冲击作用是造成基底病害产生的主要原因之一。而随着我国货运需求的日益增加,有关部门将逐渐增加既有铁路的货运列车行车密度或轴重。但是这种改变将导致隧道基底围岩直接承受列车荷载的振动冲击力增大,进而加剧隧道基底病害的产生及发展。另外一方面,重载货运线路建设过程中,关于有砟/无砟道床的选型也一直存在争议。为了解决这些问题,需要专门研究列车振动在隧道及基底围岩中的传播规律,轴重、车速等参数的影响规律,以及有砟/无砟两种道床型式下基底围岩中振动传播规律的差异,为隧道基底病害的防治、以及道床选型提供参考。本文以神朔线霍家梁隧道为工程背景,综合运用资料调研、现场测试、数值分析等手段,分析了轴重、基底病害对钢轨、轨枕、隧道壁及围岩的影响规律,并进一步对比分析了有砟、无砟两种轨道型式下,不同轴重及车速条件下隧道基底围岩的动力响应规律。主要工作内容及结论如下:1、在霍家梁隧道内进行振动测试,获取轨道及隧道结构振动实测数据,分析不同轴重列车经过正常(无病害)、病害断面时轨道及隧道结构的振动响应特性。结果表明:隧道基底振动响应随轴重增加而增大,其中10Hz以下、50-1000Hz频段更为明显;轴重的增加使轨枕振动响应在2-200Hz频段内增大,使钢轨振动响应在1-50及70-500Hz频段内增大;基底病害导致基底、隧道壁、轨枕的振动响应均有所增大,在频域上这三处响应的明显增大频段分别为150-400Hz、100-330Hz、10-200Hz。2、根据霍家梁隧道实际情况建立轨道-隧道-土体三维动力有限元模型,利用实测数据对模型单元划分方法、边界处理等进行校核,获得了可以准确分析基底围岩振动响应的模拟实际工况的三维动力有限元模型,进而采用该模型对霍家梁隧道基底围岩振动影响范围进行分析,结果表明:振动在基底围岩中呈现以隧道重载侧轨道中心下方为中心向四周衰减的趋势;27t轴重列车对基底围岩的振动影响范围为10m;确定了采用围岩竖向应力及振动加速度有效值两个指标进行后续研究。3、采用上述建模方法分别建立有砟、无砟两种轨道型式下的轨道-隧道-土体三维动力有限元模型,对比分析有砟、无砟两种轨道型式下,轴重、车速等因素对基底围岩动力响应的影响规律。结果表明:对于基底围岩相同位置处,有砟轨道工况的基底围岩竖向应力及加速度有效值均小于无砟轨道,且随轴重的增加,无砟轨道型式下基底围岩加速度有效值及竖向应力峰值的增加量比有砟轨道型式下的更敏感,因此从列车振动角度考虑,在同等围岩等级地段修建重载铁路应优先采用有砟轨道;随轴重增加,有砟、无砟轨道下基底围岩的竖向应力及加速度有效值均随之增加,即基底围岩发生病害的可能性也将提高。
[Abstract]:Mountain tunnel disease is serious in China, especially in tunnel base.According to investigation, reciprocating vibration impact of train load is one of the main causes of foundation disease.With the increasing demand of freight transportation in China, the relevant departments will gradually increase the train density or axle load of the existing railway.However, this change will lead to the increase of vibration impact force of the surrounding rock of the tunnel foundation directly under train load, which will further aggravate the generation and development of the tunnel foundation disease.On the other hand, the selection of ballastless / ballastless bed has always been controversial in the construction of heavy haul freight lines.In order to solve these problems, it is necessary to study the propagation law of train vibration in tunnel and surrounding rock, the influence law of axle load, speed and so on, and the difference of vibration propagation law between the two types of ballast and ballastless roadbed.It provides a reference for the prevention and treatment of tunnel foundation disease and the selection of the road bed.Taking the Huojialiang tunnel of Shenshuo line as the engineering background, this paper analyzes the influence of axle load and foundation diseases on rail, sleeper, tunnel wall and surrounding rock by means of comprehensive application of data investigation, field test and numerical analysis.Furthermore, the dynamic response of the surrounding rock of the tunnel foundation under different axle loads and speeds is compared and analyzed under the ballastless and ballastless track types.The main contents and conclusions are as follows: 1. Vibration test is carried out in Huo Jialiang Tunnel, and the measured data of track and tunnel structure vibration are obtained.The vibration response characteristics of track and tunnel structure of different axle load trains passing through normal (disease-free and diseased section) are analyzed.The results show that the vibration response of the tunnel base increases with the increase of the axial load, and the vibration response of the sleeper increases in the 2-200Hz frequency band and the rail vibration response in the 1-50 and 70-500Hz frequency bands with the increase of the shaft load, especially in the 50-1000Hz frequency band below 10Hz.The vibration response of the basement, tunnel wall and sleeper is increased with the frequency range of 150-400 Hz ~ (-1) ~ (100) ~ (30) Hz ~ (10 ~ (-200)) Hz 路2, respectively. According to the actual situation of Huojialiang Tunnel, a three-dimensional dynamic finite element model of rail-tunnel and soil is established.By using the measured data to check the method of model element partition and boundary treatment, a three-dimensional dynamic finite element model is obtained, which can accurately analyze the vibration response of surrounding rock in the basement.Furthermore, the model is used to analyze the influence range of surrounding rock vibration on the foundation of Huojialiang Tunnel.The results show that the vibration in the surrounding rock of the basement shows a trend of attenuation around the center below the center of the heavy load side track of the tunnel. The influence range of the axle load train of 27t on the vibration of the surrounding rock is 10 m, and the vertical stress and vibration of the surrounding rock are determined.The dynamic acceleration effective value two indexes carry on the follow-up research. 3, uses the above modeling method to establish the ballast. respectively,Three-dimensional dynamic finite element model of track-tunnel-soil in ballastless two types of track is analyzed, and the influence of axle load and speed on the dynamic response of surrounding rock is compared and analyzed in ballastless and ballastless two kinds of track.The results show that the vertical stress and acceleration of the ballast track are smaller than those of the ballastless track at the same position, and with the increase of axle load, the vertical stress and acceleration of the ballast track are lower than that of the ballastless track.The effective value of the acceleration and the increase of the peak vertical stress of the base surrounding rock under ballastless track type are more sensitive than those under the ballastless track type, so considering from the view of train vibration,The ballasted track should be preferred to be used in the construction of heavy-haul railway in the same surrounding rock grade, and with the increase of axle load, the vertical stress and the effective acceleration of the surrounding rock of the foundation under the ballastless track will increase with the increase of axle load.In other words, the possibility of disease in the surrounding rock of the basement will also be increased.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451.2

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