Inside Tunnels Research Articles

Behavior and Performance Evaluation of a Concrete Pavement Considering the Temperature Condition in a Tunnel

PURPOSES: This paper investigates behavior and performance of concrete pavement in tunnel based on temperature data from field. METHODS : In this study, there are 4 contents to evaluate concrete pavement in tunnel, First, Comparison for distress was conducted at outside, transition, and inside part of tunnel. Secondly, temperature data was collected in air and inside concrete pavement in outside and inside tunnel. Thirdly, FEM analysis was performed to evaluate stress condition, based on temperature data from field. Finally, performance prediction was done with KPRP program. RESULTS: From the distress evaluation, failure of inside tunnel was much less than it of outside tunnel, Temperature change in tunnel was less than out side, and also it was more stable. According to result of FEM analysis, both curling stress status of inside tunnel was lower than it of outside tunnel. Based on KPRP program analysis, performance of inside tunnel was longer than outside. CONCLUSIONS : Through all study about behavior and performance of concrete pavement in tunnel, condition in tunnel has more advantages from environmental and distress point of view. Therefore, performance of inside tunnel was better than outside.

原子力発電施設におけるトンネル内配管の設計法

In piping design of nuclear power plant, if piping pass through buildings, piping design considers relative displacement for seismic. In this case, piping needs to bend to reduce effect of relative displacement. However, in case of piping pass through a tunnel, piping cannot have big bending curve. So, the case of piping pass through a tunnel is severe condition for piping design. In this paper, to establish efficient design method of piping pass through a tunnel in nuclear power plant, numerical analysis was performed. Also, to reduce effect of relative displacement, stiffness of piping was investigated. Then, computed optimal bending length was proposed and bending effect for piping perpendicular stiffness was investigated. From these results, standard piping design flow of inside tunnel was established.

Weight under Steel Wheels: Material Stock and Flow Analysis of High‐Speed Rail in China

SummaryThe construction of a nation‐wide high‐speed rail (HSR) network has emerged as a hugely expensive and ambitious infrastructure project in China. As of December 2012, some 8,800 kilometers (km) of double‐track HSR lines came into service in the country, accounting for 40% of the total HSR length in the world. The network is expected to expand to 34,000 km or longer in around two decades. As the first HSR system specially built and operated in an economically developing country, it helps integrate the sprawling economy and lift the quality of life of the increasing urban population. China's experiences in HSR are expected to be of value to other countries aiming to adopt bullet train systems, especially those at a similar level of industrialization and urbanization. This work specifically examines material stocks and flows associated with the HSR infrastructure construction in China. A major distinction from the construction of HSR tracks in Europe is that nearly 70% of the HSR tracks in China are laid upon bridges or inside tunnels, which are structures that demand great amounts of raw materials. The entire network, once completed by 2030, will cumulatively require 83 to 137 million tonnes (Mt) of steel and 560 to 920 Mt of cement. This is still a small share of China's use of material resources. Nonetheless, the massive application of the steel‐ and cement‐intensive structures deserves consideration when assessing the environmental performance of HSR over its entire life cycle.

Failure analysis of connecting bolts used for anchoring streetlights of a mountain highway

This paper presents a failure analysis of connecting bolts used for holding streetlights inside the tunnels of a mountain highway. The fracture occurred in correspondence to crevices formed in bolted joints. Fractographic and metallurgical studies indicate that the bolt failure is due to a deep crevice corrosion process that is further aggravated by the presence of chlorides coming from the spray formed inside tunnels during the winter when sodium chloride is spread for de-icing roads.Metallographic studies highlighted also that corrosion affects only bolts, while all the other joints’ components are intact. EDS analyses revealed that the bolt material was a Cu-bearing stainless steel that, in chloride media, has a bad corrosion resistance because Cu destabilises the alloy passive film. Therefore, it is recommended that the bolt material should be changed to prevent similar failures and that in such environment crevices should be avoided in design.

Experimental investigation and monitoring of a polypropylene-based fiber reinforced concrete road pavement

In this work, basic guidelines are provided for the design of a polypropylene-based fiber reinforced concrete (PFRC) road pavement, as applied in an actual testing section resting inside a tunnel of the “Quadrilatero Marche-Umbria” road empowerment project, Italy. Results of a six-month monitoring carried out on actual traffic loads are also presented, as a feedback to the designing stage. Monitoring encompasses direct measurement of the strain level inside the cast as well as acoustic measurement. It is shown that the fiber reinforced concrete technology provides an efficient, safe as well as cost-effective design solution for roadways, especially inside tunnels.

배경영상을 이용한 터널 유고 검지 방법

본 논문은 터널 내에 설치된 카메라를 이용하여 터널 내 유고를 검지하는 방법을 제안하였다. 제안한 유고 검지 방법은 터널 내 설치된 카메라에서 영상을 입력받아 실시간으로 배경영상 차이법을 이용하여 움직이는 객체를 추출하여 정지물체, 차량 외 통행, 연기, 역주행을 검지하였다. 터널 내 이동하는 객체를 검지하기 위하여 객체의 이동 정보를 이용하여 능동적인 배경영상을 생성하였으며, 터널 내에서 발생하는 조명의 변화, 터널 입 출구에서 발생하는 외부 조명의 영향에 강인한 유고 검지 방법을 개발하였다. 제안한 방법의 성능을 알아보기 위하여 전남 여수의 마래터널 및 엑스포터널, 전북 임실의 운암터널에서 실험영상을 취득하였다. 실험에 사용한 영상의 개수는 정지물체 20건, 차량 외 통행 20건, 연기 4건, 역주행 10건이며 검지율은 정지물체, 차량외통행, 역주행은 실험 영상에서 모두 검지하였으며 연기의 경우 3건을 검지하여 우수한 성능을 확인할 수 있었다. 제안한 방법은 현재 전남 여수의 마래터널 및 엑스포터널, 전북 임실의 운암터널에서 운영중에 있으며 정확한 성능을 알아보기 위해서는 터널 내에서 실제 발생하는 유고 동영상을 획득한 뒤 성능 평가를 해야 할 것으로 사료된다. This study suggested a method of detecting an incident inside tunnel by using camera that is installed within the tunnel. As for the proposed incident detection method, a static object, travel except vehicles, smoke, and contra-flow were detected by extracting the moving object through using the real-time background image differencing after receiving image from the camera, which is installed inside the tunnel. To detect the moving object within the tunnel, the positive background image was created by using the moving information of the object. The incident detection method was developed, which is strong in a change of lighting that occurs within the tunnel, and in influence of the external lighting that occurs in the entrance and exit of the tunnel. To examine the efficiency of the suggested method, the experimental images were acquired from Marae tunnel and Expo tunnel in Yeosu of Jeonnam and from Unam tunnel in Imsil of Jeonbuk. Number of images, which were used in experiment, included 20 cases for static object, 20 cases for travel except vehicles, 4 cases for smoke, and 10 cases for contra-flow. As for the detection rate, all of the static object, the travel except vehicles, and the contra-flow were detected in the experimental image. In case of smoke, 3 cases were detected. Thus, excellent performance could be confirmed. The proposed method is now under operation in Marae tunnel and Expo tunnel in Yeosu of Jeonnam and in Unam tunnel in Imsil of Jeonbuk. To examine accurate efficiency, the evaluation of performance is considered to be likely to be needed after acquiring the incident videos, which actually occur within tunnel.

터널 내 대기오염물질의 공간분포 예측

The need for management of tunnel air quality is imminent considering the rapid increase of number and span of tunnels in Korea. To investigate spatial distribution of within tunnels, were measured and model simulations were performed in Namsan 1 tunnel. Results show that concentrations were 250 ppm to 400 ppm higher in the exit than tunnel entrance. Also, concentrations were 200 ppm to 300 ppm lower inside no ventilating vehicle than in the tunnel. Both experimental and model simulation results show that spatial distribution and concentration gradient of air pollutant inside tunnel are highly dependent on traffic density.

An Empirical Study of the Effects of Road Tunnel on Driving Performance

This study focused on driving inside road tunnel and is aimed to establish how drivers behave inside tunnel as well as approaching it and exiting from it. The paper analyses the effects of tunnel on drivers performance using driving simulator. A tunnel scenario is reproduced in CRISS simulator and driving parameters are compared with the data of a control scenario, characterized by the same road alignment, but without tunnel. Results match several findings of epidemiological studies on real-world tunnel, providing strong support to the use of driving simulation for studying drivers’ behaviour and its consequence on road safety.

Propagation Mechanism Modeling in the Near-Region of Arbitrary Cross-Sectional Tunnels

Along with the increase of the use of working frequencies in advanced radio communication systems, the near-region inside tunnels lengthens considerably and even occupies the whole propagation cell or the entire length of some short tunnels. This paper analytically models the propagation mechanisms and their dividing point in the near-region of arbitrary cross-sectional tunnels for the first time. To begin with, the propagation losses owing to the free space mechanism and the multimode waveguide mechanism are modeled, respectively. Then, by conjunctively employing the propagation theory and the three-dimensional solid geometry, the paper presents a general model for the dividing point between two propagation mechanisms. It is worthy to mention that this model can be applied in arbitrary cross-sectional tunnels. Furthermore, the general dividing point model is specified in rectangular, circular, and arched tunnels, respectively. Five groups of measurements are used to justify the model in different tunnels at different frequencies. Finally, in order to facilitate the use of the model, simplified analytical solutions for the dividing point in five specific application situations are derived. The results in this paper could help deepen the insight into the propagation mechanisms in tunnels.

Fireproof Design on City Traffic Road Tunnel

The paper analyses the characteristics and reasons of fire occurring inside city traffic road tunnel, With an example of road tunnel project from Guangzhou, The paper presents the contents and emphases of fireproof design on city traffic road tunnel, which covers framework design , aeration design and refuge establishment .

Modelo conceptual del sistema acuífero de Enchereda (La Gomera, Islas Canarias): contribuciones a otras islas volcánicas

La elaboración de modelos conceptuales en acuíferos de islas volcánicas presenta una elevada dificultad debido a la complejidad estructural de los materiales volcánicos, incrementada por 1) los procesos de destrucción (p. ej., deslizamientos de flanco) y 2) la intrusión de diques, que pueden actuar como zonas de flujo preferente o sobreelevando el agua localmente. En algunos casos, la falta de información hidrogeológica en el interior de las islas dificulta aún más la caracterización del funcionamiento de los acuíferos en estas zonas. En este trabajo se evalúa el papel de los diques y de los depósitos volcanoclásticos en el flujo regional de la zona de Enchereda (La Gomera, Islas Canarias) y en particular, en su zona más elevada. En esta zona se definen tres unidades hidroestratigráficas: los Basaltos Antiguos Inferiores moderadamente permeables; a techo las Brechas Volcánicas de baja permeabilidad; y por encima los Basaltos Antiguos Superiores, permeables. Las brechas parecen actuar como límite inferior impermeable del acuífero y en su reconstrucción se observa que presentan una geometría coherente con un buzamiento general hacia el ESE de aproximadamente 13º, condicionando el flujo regional del agua en el acuífero. La cartografía de los diques mediante fotografía y ortofotografía aérea así como en campo y en el interior de la galería de Ipalán, ha permitido identificar cuatro familias de diques. Los diques NO-SE son los más abundantes, con una densidad máxima de más de 10 diques/100 m, similar a otras zonas de rift en volcanes oceánicos. Estos diques son paralelos al flujo regional del agua en el acuífero y actuarían por tanto como zonas de flujo preferente, mientras que los diques con direcciones N-S y NE-SO sobreelevarían el nivel piezométrico, generando una superficie escalonada, al ser perpendiculares a la dirección flujo. Por último, los diques E-O no parecen influir de manera significativa en el acuífero. Nuestros resultados plantean la necesidad de reevaluar principalmente la influencia de los diques en el flujo regional de acuíferos en otras islas volcánicas en las que su papel se ha minimizado, ya que la superposición de diferentes familias de diques puede condicionar el movimiento del agua en el acuífero.

Turbulent heat and mass transfer through air curtains devices for the confinement of heat inside tunnels

The influence of flow instabilities on the efficiency of a twin-jet air curtain formed by a cold stream parallel to a hot stream was studied. Two cases were considered: the Reynolds number and mean flow velocity of both streams were set to 1000 and 3 m/s, respectively. The results obtained from 3D LES simulations were compared with experimental data and earlier LES numerical results using the FDS code. Energy spectra exhibit decay laws with − 5/3 and − 3 slopes. Instabilities with a characteristic Strouhal number of about 0.4 were detected. Kelvin–Helmoltz type instabilities play a more significant role than the Görtler type instabilities present at the wall for applications of plane impinging jets to ambience separation.

Study of Constructive Materials and Structure inside Long Highway Tunnel Based on Environment Factors

The selection of constructive materials and structure inside long highway tunnel was studied aiming at the relatively closed internal structure of long highway tunnel combined with its environmental factors such as noise,illumination,temperature and humidity. This paper put forward the selection principle of materials and structure on pavement and wall inside highway tunnel, and confirmed suitable reflecting materials of pavement and noise-reducing materials of wall. Furthermore, the thesis designed materials and structure of pavement and wall in noise-reduction optimization. The research has an important instructional function on improving driving environment and noise-reduction effect and promoting the construction of resource-conserving and environment-friendly society and realizing sustainable development.

On the ability of twin jets air curtains to confine heat and mass inside tunnels

The ability of DS-TJ curtains to confine heat inside tunnels is studied both numerically and experimentally. The Fire Dynamics Simulator (FDS) code was used to perform 3D numerical simulations, while temperature and velocity measurements were obtained by fine thermocouples and Laser Doppler Velocimetry (LDV), respectively. Mean velocity and temperature profiles from simulations were compared with experimental data. Two cases are considered: a first case with Re = 1000 for the twin jets, and a second case where the exit velocity of both jets is the same (3 m/s). A confinement coefficient was proposed to compare both cases, revealing that the first case is more effective in avoiding heat leakage. The instabilities in the mixing layers and the flow structure in the impinging region are responsible for the heat and mass transfer through the DS-TJ.

Prediction of the air wave due to blasting inside tunnels: Approximation to a ‘phonometric curve’

A review of the results of a previous research, has pointed out that only the magnitude of the blasting air wave at the tunnel portal depends on the tunnel and blasting design parameters (section, length, distance to the portal, maximum charge per delay…). For a given sound level at the tunnel portal, the magnitude of the air wave outside the tunnel depends on the attenuation due to natural or artificial barriers, similar to how a lamp focuses the light more along a given direction than along others. In this work, the air wave propagation outside the tunnel is briefly explained and a phonometric and iso-attenuation curves are proposed in order to represent the phenomenon and to synthesize the solution for a given case. Finally, a charge–distance curve is proposed in order to solve the problem in an easy way.

Risk analysis of explosions in trains by fluid–structure calculations

The effects of explosions inside trains and the subsequent risk of injuries and fatalities have been investigated. The work has been carried out through numerical simulations with models developed in the explicit finite element program Europlexus. Fluid–structure interaction calculations have been performed capturing all blast wave propagation phenomena, such as reflections, channelling etc. An aluminium frame-type and a honeycomb-type construction have been considered for the train body. Suitable failure criteria have been implemented for the laminated glass of the doors and windows. A relatively stiff honeycomb structure exhibits small displacements and limited failure. Results also show that the risk inside such a train is similar to that inside a train built of a frame structure. Trains in free-field and inside tunnels have been examined. The influence of the glazing and of internals objects, like lightweight doors, compartments, chairs, and passengers, on risk distribution inside the train is efficiently calculated and discussed.

A Basic Study on Countermeasure Against Aerodynamic Force Acting on Train Running Inside Tunnel Using Air Blowing

A basic study of flow controls using air blowing was conducted to reduce unsteady aerodynamic force acting on trains running in tunnels. An air blowing device is installed around a model car in a wind tunnel. Steady and periodic blowings are examined utilizing electromagnetic valves. Pressure fluctuations are measured and the aerodynamic force acting on the car is estimated. The results are as follows: a) The air blowing allows reducing the unsteady aerodynamic force. b) It is effective to blow air horizontally at the lower side of the car facing the tunnel wall. c) The reduction rate of the unsteady aerodynamic force relates to the rate of momentum of the blowing to that of the uniform flow. d) The periodic blowing with the same frequency as the unsteady aerodynamic force reduces the aerodynamic force in a manner similar to the steady blowing.

Analysis of blast wave propagation inside tunnel

The explosion inside tunnel would generate blast wave which transmits through the longitudinal tunnel. Because of the close-in effects of the tunnel and the reflection by the confining tunnel structure, blast wave propagation inside tunnel is distinguished from that in air. When the explosion happens inside tunnel, the overpressure peak is higher than that of explosion happening in air. The continuance time of the blast wave also becomes longer. With the help of the numerical simulation finite element software LS-DYNA, a three-dimensional nonlinear dynamic simulation analysis for an explosion experiment inside tunnel was carried out. LS-DYNA is a fully integrated analysis program specifically designed for nonlinear dynamics and large strain problems. Compared with the experimental results, the simulation results have made the material parameters of numerical simulation model available. By using the model and the same material parameters, many results were adopted by calculating the model under different TNT explosion dynamites. Then the method of dimensional analysis was used for the simulation results. As overpressures of the explosion blast wave are the governing factor in the tunnel responses, a formula for the explosion blast wave overpressure at a certain distance from the detonation center point inside the tunnel was derived by using the dimensional analysis theory. By comparing the results computed by the formula with experimental results which were obtained before, the formula was proved to be very applicable at some instance. The research may be helpful to estimate rapidly the effect of internal explosion of tunnel on the structure.

On The Aerodynamics of Car Body Vibrations of High-Speed Trains Cruising Inside Tunnels

Aerodynamically induced car body vibrations of high-speed trains inside tunnels have for approximately two decades been recognized as a problem in Japan, while other nations’ high-speed rail services have not reported similar problems. In order to shed light on this contradiction the scope of the present paper is to primarily explore tail car vibrations of Deutsche Bahn AG’s high-speed train ICE 2 and Japan Railways series 300 Shinkansen train. Despite similarities of these two trains the problems are reported only for the latter. Several large eddy simulations are carried out to predict the aerodynamics around simplified and smooth models of the above mentioned trains inside tunnels. The results focus on the ability to resolve PPD (propagating pressure disturbances) generated alongside the bodies, unsteady aerodynamic forces and their corresponding frequencies. Mesh refinement studies are undertaken for both train models, where mesh independence is quite a challenge for this type of application. Affordable meshes appropriate for LES could only be achieved for models confined to a typical car length. For smooth models and for a model with three generic inter-car gaps, the high spatial frequency of the resolved PPD does not make them sufficient to upset the ride quality of a car. A low frequency mode that strongly affects the forces of the tail of the Shinkansen models is described, which is caused by the confinement of the tunnel walls. A study of the implications of the lateral distance to the wall is further investigated. The findings reveal that the effects of the low frequency mode intensify with a narrow wall clearance, corresponding to the nominal lateral position of the train.

Phylogenetic Evidence for an Association Between Tunneling Behavior and the Evolution of Horns in Dung Beetles (Coleoptera: Scarabaeidae: Scarabaeinae)

Dung beetles employ numerous behavioral strategies to sequester dung away from other insects, and these have been broadly grouped into two categories: species that dig tunnels beneath the dung (tunnelers) and species that roll dung on the surface of the soil (rollers). Many species also are armed with rigid exoskeletal outgrowths called horns. Horns function as weapons, and horn sizes can be extreme. One widespread pattern within dung beetles is that tunneling species often have horns, whereas rolling species almost always do not, suggesting that residing (and fighting) inside tunnels at the dung deposition site may be an important ecological prerequisite for the evolution of horns in dung beetles. Here, we test explicitly for an historical association between tunneling behavior and the evolution of horns using a recent phylogeny for the scarabaeine dung beetles. We show that all eight of the independent gains of horns included in our analyses occurred on branches of the phylogeny reconstructed as tunneling, and that one of the three evolutionary losses of horns occurred on a branch that had lost tunneling behavior. We interpret this as evidence for a biologically meaningful association between tunneling behavior and the evolution of enlarged or exaggerated weapons such as horns, supporting the ideas of Eberhard and others that beetle horns may be most “beneficial” when used within the confines of restricted spaces such as burrows or tunnels.