Ordinary Tunneling Research Articles

Study of the Physiological Characteristics of Drivers Facing Apparent Changes in Highway Tunnel Structures

The increasing frequency of structural damage and reinforcement repairs in long-term highway tunnels necessitates an understanding of their effects on drivers. This study examines drivers’ physiological responses to visible structural changes in highway tunnels. Using a vehicle static in-the-loop platform, we created various models of apparent tunnel structure changes for simulated driving experiments. These experiments enabled a detailed analysis of the effects of such changes on driver safety, utilizing metrics such as eye movements, regions of interest, heart rate, and vehicle speed. The results show that visible alterations in tunnel structures significantly affect drivers’ physiological responses. Structural spalling and fire residues within tunnel structures notably increased drivers’ vigilance and psychological stress, resulting in a 14.7% increase in the average number of fixations, a 26.35% increase in the average duration of fixations, and a 36.05% increase in heart rate variability. Additionally, tunnel spalling tends to cause drivers to accelerate or exceed the speed limit, with maximum speeds reaching 17.87% above the designed speed. In contrast, repairs involving cover arch erection had minimal impact on drivers, with eye movement and heart rate data similar to those in ordinary tunnels. However, reinforcement with steel strips and corrugated steel in tunnels has attracted significant attention, with the area of interest exceeding 50% of the tunnel area, potentially leading to distracted driving. This study clarifies the extent of the influence of visible tunnel structure changes on drivers, providing a reference for damage assessment, reinforcement, and repair measures for long-term operated tunnels.

Vibration energy harvesting from tunnel invert-filling using rubberized concrete.

With the increasing operation mileage of urban rail transit, to ensure its operation safety, it is necessary to carry out health monitoring on the rail, tunnel, and other structures. How to capture the vibration energy generated by train operation and use it to monitor the power supply of sensors has become a research hotspot in recent years. In this paper, a new type of spherical energy harvester is designed for rubberized concrete tunnel invert-filling. Based on the calculation model of rubberized concrete tunnel invert-filling under train load, the vertical displacement, stress, voltage, and total electric energy are analyzed. The main conclusions are as follows: (1) The spherical energy harvester is embedded in the rubberized concrete tunnel invert-filling in the form of an array, and the optimal position is 5mm below the sleeper. (2) Ten energy harvesters are set up in the scope of a 6-m-long rubberized concrete tunnel invert-filling. The electric energy of the millijoule level can be generated when an A-type train of 8-vehicle formation passes by. If the departure interval of 5min/trip is calculated, the total electric energy harvesting in 1h is 122.4mJ. (3) Rubberized concrete tunnel invert-filling is more conducive to energy harvesting than ordinary concrete tunnel invert-filling. When the content of rubber is 10%, the total electric energy harvesting by the energy harvester array inside the tunnel invert-filling is 5% higher than that of the ordinary concrete, and the mechanical performance indexes such as stress are within the safe range. The research results of this paper have reference value for further exploration of electric energy harvesting in the running environment of rail transit trains.

Research on Experimental and Numerical Methods for Mechanical Properties of Lightweight Hollow Precast Utility Tunnels

In this paper, the mechanical properties of hollow precast utility tunnels are studied by experimental and numerical methods. Through full-scale experiments, the failure modes of ordinary and hollow utility tunnels are studied, and the failure stages of the structures are classified based on the bearing capacity and damage to the structures. The nonlinear finite element model is used to simulate the behavior of the structure, and the optimal design of the structure under load type and the hollow ratio are discussed based on the finite element method. The theoretical calculation method of the bearing capacity for hollow structures in each stage is proposed, and its application scope is discussed. The finite element analysis can effectively predict the mechanical properties of the structure, and the failure of the utility tunnel structure is dependent on the shear bearing capacity. Although hollow design advances the structural damage under point load, the hollow structure has significant advantages under uniform loads or reasonable hollow ratios. It is reasonable to calculate the cracking load considering moment distribution at section centroid and the failure load considering the combined action of flexural and shear stress, but the hollow ratio should be less than 16%. Under reasonable hollow ratio or load conditions, the hollow design has little effect on the bearing capacity of the structure and can reduce the weight, which has practical value for architecture and construction.

Study on Optimization of Tunnel Ventilation Flow Field in Long Tunnel Based on CFD Computer Simulation Technology

With the rapid development of tunnel construction, more and more long tunnels are being designed and built. In contrast to ordinary tunnels, long tunnels are characterized by large construction distances and difficult ventilation. In this study, gallery ventilation systems in the construction of long tunnels were studied. Combined with the CFD software FLUENT, a three-dimensional model of tunnel ventilation of a double tunnel was established, and a numerical simulation analysis of the ventilation flow field was carried out and optimized the flow field of gallery ventilation. We found that the main circulation air flow of gallery ventilation was formed by the jet fan, which was installed near the air flow-in tunnel. We also determined the main factors that affect the ventilation effect in gallery ventilation, including the wind wall formed by the high-speed airflow at the cross-aisle and found that the draft fan in front of the cross-aisle could eliminate the wind wall and improve the ventilation effect. The influence of the location and type of the draft fan on the elimination of air flow structure was studied, and the best fan layout scheme suitable for the site was determined. The ventilation scheme of the tunnel was optimized.

Surface control techniques for tunnels in karst areas under airport taxiways

Under the conditions of karst development and soft upper and hard lower strata, ground-settlement control for tunnels under airport taxiways is stricter than for ordinary tunnels. Tunnel construction methods and karst disposal measures are also important. These are engineering problems that need to be solved urgently to ensure the safe passage of tunnels under airport taxiways. Taking the intercity railway tunnel under taxiways T3 and T4 of Guangzhou Baiyun international airport as a case study, theoretical analysis and field tests on karst treatment measures and ground-settlement control measures were conducted. Karst treatment measures and a pile support plate (PSP) structure have been proposed to support the taxiways. The effect of the system was analysed numerically method and on-site surface settlement was monitored. The maximum monitored settlement of T3 and T4 taxiway surfaces was 5.90 mm and the differential settlement was 0.12‰. The numerical results provided a similar value and did not exceed the settlement control standard for airport taxiways. The key technologies for the construction of tunnels under airport taxiways in karst areas and upper soft and lower hard strata are presented, karst disposal measures are summarised and the PSP protection system is described. The results provide reference information for similar projects.

Quantitative design method for anti-dislocation joints for tunnels passing through active faults

Given the rapid development of Chinese transportation networks, a substantial number of tunnels are under construction or will be built in mountainous areas. However, certain tunnels must be constructed through active fault zones and will be destroyed by the dislocation of active faults. In the present Chinese codes, three measures are suggested, including over cutting the cross-section, setting up anti-dislocation deformation joints, and strengthening the lining, but there is a lack of quantitative design method. In this study, we present a design method for anti-dislocation deformation joints to improve the anti-dislocation ability of the tunnel passing through active fault. First, formulae related to the design method for anti-dislocation deformation joints were proposed to consider different fault and tunnel parameters. Then, the proposed method and the formulae were validated by experimental model tests and numerical analyses. The experimental models were prepared according to the geological data of the Beichuan-Yingxiu fault in Sichuan Province, China. Models on 1:30 scale were subjected to fault dislocation tests in two cases: tunnels with ordinary linings and tunnels with anti-dislocation deformation joints. The test results show that the longitudinal strain of the lining with anti-dislocation deformation joints in the fault fracture zone decreased to 32% of that of the ordinary lining, and the transverse strain also significantly decreased. The maximum normal stress between the surrounding rock and lining was approximately 80% of the value for the ordinary lining. The lining with anti-dislocation deformation joints experienced less damage than the ordinary lining. The results of numerical calculation suggest that anti-dislocation deformation joints determined by the proposed method could effectively reduce the forces and bending moments of the lining. The proposed method for anti-dislocation deformation joints could be used to mitigate the seismic damage of tunnels passing through active fault zones.

Shaking Table Test on the Tunnel Dynamic Response under Different Fault Dip Angles

Fault-crossing tunnels are often severely damaged under seismic dynamics. Study of the dynamic response characteristics of tunnels crossing faults is thus of great engineering significance. Here, the Xianglushan Tunnel of the Central Yunnan Water Diversion Project was studied. A shaking table experimental device was used, and four sets of dynamic model tests of deep-buried tunnels with different fault inclination angles were conducted. Test schemes of model similarity ratio, similar material selection, model box design, and sine wave loading were introduced. The acceleration and strain data of the tunnel lining were monitored. Analysis of the acceleration data showed that when the input PGA was 0.6 g, compared with the ordinary tunnel, the acceleration increases by 117% when the inclination angle was 75°, 127% when the inclination angle was 45°, and 144% when the inclination angle was 30°. This indicates that the dynamic response of the cross-fault tunnel structure was stronger than that of the ordinary tunnel, and the effect was more obvious as the fault dip angle decreased. Analysis of the strain data showed that the strain response of the fault-crossing tunnels was more sensitive to the fault dip. The peak strain and increase in fault-crossing tunnels were much larger than those of ordinary tunnels, and smaller fault dips led to larger increases in the strain peak; consequently, the tunnel would reach the ultimate strain and break down when the input PGA was smaller. Generally, the influence of fault inclination on the dynamic response of the tunnel lining should receive increased consideration in the seismic design of tunnels.

Entrance zone length of extra-long undersea tunnels based on vision adaptation

As a new form of urban traffic, extra-long undersea tunnels have emerged as an important means of transportation to promote the development of coastal cities in recent years. Owing to the black hole effect and the special alignment at the entrance of these tunnels, the occurrence of a traffic accident can often lead to casualties and traffic paralysis. This study analyzed the main characteristics of the tunnel entrance length division methods proposed by the International Commission on Illumination (CIE), the United States, and China, and discussed the main differences between the lighting environments of extra-long undersea tunnels and ordinary highway tunnels. A real vehicle test was carried out in an extra-long undersea tunnel, and primary data, such as the driver’s pupil area and tunnel illuminance, under continuous time series were collected. The drivers’ pupil variation characteristics while driving into the tunnel during the daytime were studied, and a mathematical model of the change in the pupil area with time was constructed. In addition, a method for calculating the drivers’ dark adaptation time at the tunnel entrance was established, with the pupil area growth rate and volatility less than 15% as the indices. Based on the driver’s visual adaptation characteristics and stopping sight distance, a method for the entrance zone length of the extra-long undersea tunnel was proposed. The lengths were enhanced by 41.176, 34.513, and 20.635%, respectively, compared to those obtained using the CIE/USA/CHN standards. In view of the different calculation methods and results of the existing standards, our method overcomes the limitations of the existing methods that rely excessively on the physical and lighting characteristics of tunnels. Moreover, it considers the potential safety hazards where the main road and the ramp merge near the entrance of the tunnel, and provides a new idea for the safe length of the entrance zone from the perspective of the driver’s visual physiological response.

Stress-Release Law and Deformation Characteristics of Large-Span Tunnel Excavated with Semi Central Diaphragm Method

The proportion of large-span tunnels in newly-built highway tunnels is getting higher and higher, revealing the stress release law and deformation characteristics of the tunnel at different excavation steps has important guiding significance for the rational design of the supporting structure parameters. In this paper, a typical section of the Laohushan Tunnel was selected to analyze the stress and deformation response of the large-span tunnel excavated with the semi central diaphragm method (SCDM), with the numerical simulation and field monitoring method. The study found that during the excavation of the large-span tunnel with the SCDM, the stress and deformation response characteristics are different from those ordinary tunnels. Influenced by the settlement of the vault, there was a significant outward expansion tendency, and a high degree of stress concentration in the sidewall. In particular, the supporting structure at the sidewall has a deformation characteristic of expanding outward and then converging inward. In this paper, the in-depth analysis of the stress release law and deformation characteristics of the excavation process of large-span tunnels can provide reference for the excavation and support parameter design of similar projects.

Experimental and numerical study on critical ventilation velocity for confining fire smoke in metro connected tunnel

Extensive studies have been conducted on critical velocity in ordinary single tunnels while still lacking the direct guidance for smoke confinement in connected metro tunnels, which is noteworthy as metro networks have expanded in recent years. Focusing on this issue, this study aimed to predict the critical velocity for confining fire smoke in connected metro tunnels. Model experiments and numerical simulations were carried out while considering the inclination of connected tunnels and the incorporation of longitudinal ventilation in a main tunnel, which represent the typical structure and ventilation characteristics of metro connected tunnels. The results show that, under a node-area fire scenario, the critical velocity for confining upstream smoke in a connected tunnel was lower than that for an ordinary single tunnel, caused by the discrepancy in smoke density and heat allocation. Additionally, due to the stack effect driving and hindering smoke diffusion in upward and downward connected tunnels, the dimensionless critical velocity increased and decreased with the increase in upward and downward slopes, respectively. Meanwhile, smoke diffusion was reduced by incorporated longitudinal ventilation in the main tunnel, resulting from a decrease in smoke temperature. A prediction model of the critical velocity for confining smoke in metro connected tunnels was developed, which achieved an improvement on previous model and could support the smoke control design in such metro systems.

2-Component links with genus two Heegaard splittings

In the present paper, we consider two types of 2-component links with genus two Heegaard splittings. One of them is an ordinary tunnel number one link, and the other is a somewhat different tunnel number one link. We will try to detect the differences between those two types. In fact, we will characterize composite tunnel number one links of the second type, and tunnel number one links of the second type with essential tori.

Experimental investigation on maximum gas temperature beneath the ceiling in a branched tunnel fire

The effect of bifurcation structure in a road branched tunnel on ceiling gas temperature needs to be clarified. However, the previous studies mainly focused on the temperature distribution in ordinary single tunnel fires, it is insufficient in branched tunnels. Therefore, this paper carried out a series of reduced scale experiments in a branched tunnel to investigate the maximum excess temperature beneath the tunnel ceiling. The reduced scale experiments with heat release rates varied from 1.72 kW to 6.04 kW were conducted under natural ventilation and forced ventilation. Three bifurcation angles of 5°, 10°, and 15° were conducted. The predicted model by dividing dimensionless ventilation velocity into two parts was established on the bases of theoretical analysis and experiments. Results show that the bifurcation structure has a significant effect on the flame plume. For a given heat release rate, the maximum ceiling temperature decreases with the increasing of ventilation velocity because of the more significant cooling effect compared with oxygen supply effect. The maximum ceiling temperature varies as 2/5 power of the heat release rate when the dimensionless ventilation velocity is lower than 0.19. The affection of bifurcation angle on the maximum temperature could be ignored under natural ventilation, but this affection is reinforced under forced ventilation. The predictions by proposed model are compared with experiments and they are in good agreement.

The environment and energy consumption of a subway tunnel by the influence of piston wind

With the flourishing development of the subway construction, it becomes increasingly urgent to improve the subway tunnel environment and reduce the energy consumption of the tunnel ventilation system. The tunnel environment is significantly affected by the piston wind, which is influenced by the train speed. In this paper, a three-dimensional computational model of a subway tunnel is developed and validated through experiments. The model is used to study the carbon dioxide concentration and thermal environment of the subway tunnel. The optimal train speed is proposed with the aim to minimize the volume of mechanical supply air and to optimize the carbon dioxide concentration and thermal environment of the tunnel. In parallel with the considerations of tunnel environment, the subways in 25 cities of China are analyzed to study the energy conservation of the tunnel ventilation system by making full use of piston wind. The results indicate that the optimal train speed is 30 m/s based on the carbon dioxide concentration and thermal environment. The effective utilization of the piston wind can reduce 13%∼32% of the energy consumption for tunnel ventilation. The calculation method of the optimal train speed developed in this paper is also applicable to ordinary railway tunnels and high-speed railway tunnels.

Influence Zone Division and Risk Assessment of Underwater Tunnel Adjacent Constructions

Compared with ordinary tunnels, the influence analysis of underwater tunnel adjacent constructions is more complicated. At present, the empirical method used to divide the influence zone of the tunnel adjacent constructions has great uncertainty. So it is of great significance for actual construction and design to determine the influence zone accurately according to theoretical calculations. In this paper, based on the Hoek–Brown nonlinear failure criterion of rock mass and taking seepage factor into account, the stress state of rock mass around the underwater tunnel adjacent constructions can be deduced by elastoplastic theory. Then combined with the concept of “loose zone-bearing zone”, the influence zone division method of underwater tunnel adjacent constructions is proposed, and it is applied to the analysis of engineering examples. Through the deduced theoretical formulas, the influence zone of underwater tunnel adjacent construction can be divided into extensively strong, strong, relatively strong, weak, and noninfluence zones. Corresponding the influence zones with the risk levels in the code, different control measures are adopted for different risk levels, which can provide certain guidance for the design and construction of tunnel in practical engineering.

First-principles study of graphyne/graphene heterostructure resonant tunneling nano-transistors

Resonant tunneling transistors have received wide attention because of their ability to reduce the complexity of circuits, and promise to be an efficient candidate in ultra-high speed and ultra-high frequency applications. The chemical compatibility between graphene and graphdiyne implies that they can be combined into various configurations to fulfill ultra-high frequency nanotransistor. In the present paper, two novel resonant tunneling transistors based on graphene/graphdiyne/graphene double-heterojunction are theoretically developed to model two new kinds of bipolar devices with two representative graphdiyne nanoribbons. The electronic structures of two pristine graphdiyne nanoribbons are investigated by performing the first-principles calculations with all-electron relativistic numerical-orbit scheme as implemented in Dmol3 code. The electronic transport properties including quantum conductance (transmission spectrum) and electrical current varying with bias-voltage for each of the designed graphdiyne nanoribbon transistors are calculated in combination with non-equilibrium Green function formalism. The calculated electronic transmission and current-voltage characteristics of these transistors demonstrate that the current is dominantly determined by resonant tunneling transition and can be effectively controlled by gate electric field thereby representing the favorable negative-differential-conductivity, which is the qualified attribute of ultra-high frequency nanotransistor. It follows from the <i>I</i>-<i>U</i><sub>b</sub> variations explained by electronic transmission spectra that quantum resonance tunneling can occur in the proposed star-like graphdiyne (SGDY) and net-like graphdiyne (NGDY) nanoribbon transistors, with the resonance condition limited to a narrow bias-voltage range, leading to a characteristic resonant peak in <i>I</i>-<i>U</i><sub>b</sub> curve, which means the strong negative differential conductivity. Under a gate voltage of 4 V, when the bias-voltage rises up to 0.6 V (0.7 V), the Fermi level of source electrode aligns identically to the quantized level of SGDY (NGDY) nanoribbon channel, causing electron resonance tunneling as illustrated by the considerable transmission peak in bias window; once the source Fermi level deviates from the quantized level of SGDY (NGDY) channels at higher bias-voltage, the resonance tunneling transforms into ordinary electron tunneling, which results in the disappearing of the substantial transmission peak in bias window and the rapid declining of current. The designed SGDY and NGDY nanotransistors will achieve high-level negative differential conductivity with the peak-to-valley current ratio approaching to 4.5 and 6.0 respectively, which can be expected to be applied to quantum transmission nanoelectronic devices.

Experimental and numerical study on fire-induced smoke temperature in connected area of metro tunnel under natural ventilation

Previous studies have usually focused on an ordinary single tunnel fire. However, the structural effect of metro connected tunnel area on the smoke temperature still needs to be clarified. Therefore, this paper aims to modify the current model for predicting the fire-induced smoke temperature considering different sloped conditions in main and connected tunnels. Small-scale and full-scale experiments were conducted with the main tunnel and connected tunnel being horizontal, then extended numerical simulations were performed to clarify the common inclined effect of both the main and connected tunnel on the smoke temperature under natural ventilation. The results show that, maximum smoke temperature varies with a reduction or enhancement of the heat accumulation caused by slope conditions in both the main and connected tunnels. The dimensionless temperature profiles along the smoke spread depends on the slopes of current tunnel itself and are affected little by slopes of another connected one. Prediction models for the maximum smoke temperature and longitudinal temperature profiles were further developed by taking the main and connected tunnel slopes into account. Moreover, it performs good fitting degree for the correlated temperature profile and the predicted maximum smoke temperature agree well with experimental and simulated results, which provides an easy-to-use method for estimating smoke temperature in a fire prevention design or emergency rescue in such metro system.

Study of the basement structure load under the dynamic loading of heavy-haul railway tunnel

ABSTRACT The base structure in heavy-haul railway tunnels is greatly affected by the train load, which leads to a much higher rate of basal structure disease compared with that of an ordinary tunnel. In this paper, two different axle loads of a heavy-haul train, 270 and 300 kN, are set as the research objects, and calculations for the additional load on the surface of the basement structure, including the ballast, invert arc filling, invert arc and rock, caused by a heavy-haul train in single and double lines when the classifications of the surrounding rock are III, IV and V are carried out. These calculations are all based on existing domestic specifications, research results and the layered elastic theory. In addition to the theoretical calculations, research methods including a field-embedded optical fibre grating sensor, large vibration test and real-time remote monitoring have been applied to obtain measurements that could verify the calculation. According to the study results, taking each type of rock and axle load condition into consideration, the calculations and measurements reveal that the maximal additional dynamic loads on the heavy-haul railway appear in the vertical direction of the track, and they decrease when the basal structure goes deeper. The study also finds that the surrounding rock level has a great effect on the maximal load and its attenuation in the vertical direction.

Study on Structural Service Performance of Heavy-Haul Railway Tunnel with Voided Base

The structural design of heavy-haul railway tunnels still follows the design method of ordinary railway tunnels. Most of them do not take into account the influence of large axle load of 30 t or more, let alone such problems as void of surrounding rock under long-term dynamic loads. In order to analyze the dynamic response of heavy-haul railway tunnels under long-term reciprocating cyclic dynamic loads, considering the factors such as axle load of vehicle body, unsprung mass, and track irregularity, the vibration load time-history curve of heavy-haul railway trains is determined, the three-dimensional dynamics coupling model of dynamic load-tunnel-surrounding rock is established, and the fatigue life of the structure under different void conditions is analyzed based on the S-N curve of concrete. According to the study, the loading, unloading, and vibration caused by train passing will lead to fluctuations in the vertical displacement response of the monitoring point. The peaks and valleys of the response time-history curve correspond to the effect of the train wheels rolling through. When the void is 6 m wide and 10 cm thick, the vertical displacement of the inverted arch is increased by about 9 times, the peak velocity of the inverted arch is increased by about 3.8 times, and the maximum principal stress is increased by about 47.3%, compared with the condition without void. With the same void thickness, the vertical displacement and velocity curves of the inverted arch vary significantly with the increase of the void width. The width of the base void has a significant effect on the fatigue life of the structure of heavy-haul railway tunnels. Based on the operation requirement of 100-year service life, the ultimate void width is 2 m.

Multi-terminal spin valve in a strong Rashba channel exhibiting three resistance states

In a strong spin-orbit interaction system, the existence of three resistance states were observed when two ferromagnetic (FM) contacts were used as current terminals while a separate normal metal contact pair was used as voltage terminals. This result is strikingly different from ordinary spin valve or magnetic tunnel junction devices, which have only two resistance states corresponding to parallel (RP) and antiparallel (RAP) alignments of the FM contacts. Our experimental results on a quantum well layer with a strong Rashba effect clearly exhibit unequal antiparallel states, i.e., RAP(1) > RP > RAP(2), up to room temperature. The three-states are observed without any degradation when the distance between the non-magnetic voltage probe and the ferromagnetic current probe was increased up to 1.6 mm.

터널 환경 측정 시스템 개발 및 측정 III -솔안터널 측정결과 분석-

본 논문은 터널 환경 측정 시스템 개발 및 측정 I [1], II [2]의 후속논문이다. 본 연구의 대상이 되는 터널인 솔안터널은 백두대간을 관통하는 연장 16.7 km의 루프식 단선 터널로 산악지형에 위치하며 화물열차와 승객열차가 혼용인 일반철도 터널이다. 본 논문에서는 솔안터널의 환경 측정을 위하여 터널 내부에 3개의 위치에 설치된 환경 측정 장치에서 약 1년간 측정된 온도 및 습도를 분석하였다. 선행의 연구에서는 도심지 및 도심지 인근에 위치한 터널 내부에서 측정 결과 결과에 대하여 분석하였지만, 본 논문에서는 산악지형에 위치한 터널 내부에서 측정한 온도 및 습도 등을 외부에서의 기상 측정 결과와 비교한 것으로 선행 연구와 차별성을 지닌다. 솔안터널 내부에 측정된 온도 및 습도를 월별로 지역에서의 기상 측정 결과와 비교하였으며, 여름과 겨울을 대표하는 대표적인 일자에 대해서 철도터널에서의 시간별 온도 및 습도의 변화도 분석하였다. 또한 터널 내 측정 위치에 따른 환경 특성도 분석하였다. 본 연구에서 제시한 철도터널의 환경측정 분석 결과는 터널의 환기 및 화재 시뮬레이션 등 터널의 기류의 컴퓨터 해석 및 터널의 공기질 및 온열환경과 관련된 연구에 폭넓게 사용될 수 있다. This paper is a follow-up to previous papers entitled, "Development of Tunnel-Environment Monitoring System and Its Installation" I [1] and II [2]. The target tunnel of these studies is the Solan Tunnel, which is a loop-type, single-track, 16.7-km-long tunnel located in mountainous terrain and passing through the Baekdudaegan mountain range. It is an ordinary railway tunnel designed for both freight and passenger trains. We analyzed the environmental conditions of the tunnel using temperature and humidity data recorded over approximately one year. The data were recorded using the Tunnel Rough Environment Measuring System (TREMS), which measures environmental data in subway and high-speed train tunnels and is installed in three locations inside the tunnel. Previous studies analyzed environmental conditions inside tunnels located in or near a city, whereas the tunnel in this study is located in a mountainous area. The tunnel conditions were compared with those measured outside the tunnel for each month. Hourly changes during summer and winter periods were also analyzed, and the environmental conditions at different locations inside the tunnel were compared. The results are widely applicable in studies on the thermal environment and air quality of tunnels, as well as for computer analysis of tunnel airflow such as tunnel ventilation and fire simulations.