Tunnel Research Articles

Inhibitory effect of calcium carbonate precipitation induced by Triton X-100 and microorganisms on coal dust

During underground tunnel construction, dust endangers the safety and health of workers. Microbially induced calcium carbonate precipitation (MICP) represents a novel green dust suppression technology for addressing coal dust pollution, capable of effectively mitigating coal dust pollution. Nevertheless, the concentration of urease will exert a certain influence on the performance of MICP to some extent. Therefore, how to improve the efficiency of urease activity on coal dust suppression is a popular research topic. In this study, based on MICP technology, the properties of microbial dust suppression materials were investigated through contact angle, surface tension, and unconfined compressive strength (UCS) tests in combination with molecular dynamics simulations, scanning electron microscopy, and X-ray diffraction using Bacillus megaterium and the nonionic surfactant Triton X-100. The results demonstrate that when the concentration of the bacterial solution is 20 % and the concentrations of urea and calcium chloride are 0.7 mol·L–1, the addition of 1 % Triton X-100 can increase the yield of calcium carbonate to 21.83 %, enhance the structural density of the gel, and increase the UCS by 15.63 %. The calcite and quartz formed on the coal dust surface improved its wettability with a contact angle of only 22°, showing an excellent dust-suppression effect. These research findings serve as a reference for enhancing the MICP dust suppression efficacy and have significant implications for the development and application of microbial dust-suppression agents. This dust suppression method has potential applications in quarries and underground environments.

Energy consumption and dilution of toxic gases in underground infrastructures: A case study in a railway tunnel under forced ventilation

Toxic fumes are released after blasting in underground excavations. The analysis of safe re-entry times into the work areas is essential for addressing safety and productivity concerns. In this paper, a railway tunnel 2.1 km long under forced ventilation system is selected as a case study to assess the energy consumption and re-entry times after blasting under different ventilation conditions. First, three-dimensional CFD numerical models were conducted in order to predict the migration time to reduce the levels of noxious gases below the limits established in safety regulations. Field measurements were conducted to verify the accuracy of the results obtained in the simulations. Then, additional analytical models were conducted to evaluate the energy consumed by the ventilation system. The results obtained show that the accumulated re-entry time reaches 414 h for the excavation of the tunnel employing an airflow rate of 40 m3 s−1. This time increases by 33 % when the airflow rate decreases to 30 m3 s−1. However, even though the time decreases when the ventilation volume increases, energy consumption increases significantly, reaching 1,306 MWh for a ventilation volume of 40 m3 s−1 compared to 551 MWh using an airflow of 30 m3 s−1.

Centrifuge modelling of the dynamic response of twin tunnels under train-induced vibration load

The impact of train-induced vibrations originating from underground tunnels has emerged as a significant environmental issue within urban areas. A multitude of studies, encompassing both numerical analyses and experimental investigations, have been undertaken to explore and address this concern. In the experimental tests, the dynamic characteristics of tunnels and soil has generally been studied using physical models with a single tunnel under a 1 g (gravity) environment. However, twin tunnels are commonly constructed in the field, and the stress of the soil is unrealistically simulated in 1 g models. In this paper, the dynamic characteristics of twin tunnels were studied by centrifuge testing. In this paper, results are presented from scaled model tunnel tests conducted at 50 g for four different conditions: a single tunnel, vertical twin tunnels with 60 mm spacing, horizontal twin tunnels with 60 mm and 120 mm spacing. Train load and sweep load were applied by a parallel pre-stressed actuator at the tunnel invert. Accelerometers were employed to gauge the dynamic response of both the tunnels and the surrounding soil. The experimental results illustrate that the interaction between twin tunnels has a clear amplification effect on the dynamic response of the loading tunnel, with the maximum peak particle acceleration (PPA) increasing by up to 43 %. This amplification phenomenon is reduced as the space between the twin tunnels is increased. The experimental results also indicate that the interaction between twin tunnels has a comparatively lower impact on the dynamic response of the surrounding soil when contrasted with the dynamic response of the tunnels themselves.

Selection of track form in railway tunnel from a life cycle analysis perspective

AbstractThe use of greenhouse gas (GHG) emissions as a criterion for decision-making within the rail industry is increasing. The demand for considering this criterion affects the type of decision models acceptable by railway infrastructure managers in the planning, construction, and maintenance of railway assets. The total amount of GHG emitted from a track solution in tunnels during its service life depends on the track form (i.e., ballasted track or ballastless track), the type of construction, maintenance machines used, current traffic profile, and tunnel length. However, the development in the design of ballastless track systems during recent decades to make them environmentally friendly motivates infrastructure managers to rethink and consider the use of the system. This study examines the effect of several design and maintenance factors not adequately addressed in previous research. These factors are (i) the modulus of elasticity of track support affecting the design of track forms, (ii) differences in maintenance and renewal required for track forms in the corresponding line condition, and (iii) recent developments in optimizing the environmental impact of ballastless tracks. The GHG emissions, represented by life cycle carbon dioxide equivalent (CO2e) emissions, are calculated using the climate impact software developed by the Swedish Transport Administration Trafikverket. The result is compared with the estimated emission from the conventional ballasted tracks. The method proposed in this paper is applied in a case study to study the effect of applying the optimized ballastless track system Rheda 2000® in a railway tunnel (the Hallsberg-Stenkumla tunnel) as part of a new line project in Sweden. The model applied in the study is an integral part of an integrated decision support system for effectively selecting track solutions from a lifecycle perspective. The study´s findings are: (i) the life cycle CO2 equivalent emissions by a ballastless track during its life cycle are 10% lower than that of the ballasted track, (ii) the primary total emission driver for both track form solutions is the emissions generated at the manufacturing of rails. (iii) the second important emission factor for the ballasted track solution is the emission from the renewal of the track form during its life cycle, and (iv) the second important emission factor for the ballastless track solution is concrete manufacturing.

Study on InSAR deformation information extraction and stress state assessment in a railway tunnel in a plateau area

Introduction: The study proposes a method for evaluating stress distribution in high-altitude Tibetan Plateau railway tunnels using high-precision radar satellite time-series interferometric synthetic aperture radar technology.Methods: To effectively monitor and prevent geological hazards during the construction process, this method i employed, as it serves as a component of advanced geological prediction and surrounding rock deformation monitoring technology for high-altitude tunnels, particularly in the Dongelu Tunnel of the China–Tibet Railway. The study utilizes time-series interferometric synthetic aperture radar to obtain deformation information for Dongelu Tunnel area between 2022 and 2023 from Sentinel- 1A orbit images. This quantitatively investigates the upper mountain body and line-of-sight direction along the tunnel. The deformation characteristics are correlated with high-frequency and high-precision automated vertical displacement monitoring results, determining the spatiotemporal distribution of tunnel deformation. In this study, a model that determines the vertical stress state of the Dongelu Tunnel under loading near the entrance and evaluates its health status was established.Results: The results show that the surface deformation of the mountain above the tunnel axis develops slowly and is relatively small, with a maximum vertical deformation rate of 1–3 mm/year. The average stress on the tunnel arch is 5.54 MPa, with a fluctuation range of 0.01 MPa. Temporal Q9 changes in various parts of the tunnel are periodic, with maximum fluctuations observed in December 2022. The study reveals inconsistent surface settlement of the tunnel arch and mountain above it, causing minor vertical stress changes. As the tunnel construction progresses, vertical stress variation shows periodicity because of an initial imbalance in internal stress within the mountain. Stress fluctuations near the tunnel entrance occur during the initial excavation phase, gradually diminishing as the project progresses and internal stress stabilizes.Discussion: The proposed tunnel monitoring and stability assessment method can reduce its impact on engineering construction and provide guidance for advanced geological prediction.

Why Do Drivers Decide to Violate Traffic Rules while Driving Through Road Tunnels? An Application of the Theory of Planned Behavior

Why Do Drivers Decide to Violate Traffic Rules while Driving Through Road Tunnels? An Application of the Theory of Planned Behavior

Large-Deformation Modeling of Surface Instability and Ground Collapse during Tunnel Excavation by Material Point Method

Recent rapid urbanization has led to an increase in tunnel construction, escalating the prevalence of ground collapses. Ground collapses, characterized by large deformation and strain-softening, pose a significant challenge for classical numerical theories and simulation methods. Consequently, a numerical framework combining the material point method (MPM) and strain-softening Drucker–Prager plasticity is introduced in this study to more accurately describe the evolution process and failure mechanism of the subgrade during tunnel excavation. The proposed numerical framework was validated against an analytic solution employing a typical ‘dry bottom’ dam model with solid non-linearity and large deformation; some of the results are also compared with those of the SPH method and centrifugal modeling tests to verify the validity of the MPM method in this paper. The validated model was used in this study to conduct a comprehensive analysis of surface instability and ground collapse under varying soil conditions. This included factors such as strata thickness, cohesion, internal friction angle, and a quantitative description of the development of longitudinal subsidence of the surface. The aim was to clarify deformation responses, failure patterns, and excavation mechanisms, providing insights for underground tunneling practices.

Asbestos Hazard in Serpentinite Rocks: Influence of Mineralogical and Structural Characteristics on Fiber Potential Release

Naturally occurring asbestos (NOA) represents a matter of social and environmental concern due to its potential release in the atmosphere during rock excavation and grinding in quarry and road tunnel activities. In most cases, NOA occurs in serpentinites, i.e., rocks deriving from low-grade metamorphic hydration of mantle peridotites. The potential release of asbestos fibers from serpentinite outcrops depends on several features, such as serpentinization degree, rock deformation, weathering, and abundance of fibrous veins. In this study, we selected a set of serpentinite samples from a representative outcrop in Tuscany (Italy), and we analyzed them by Optical, Scanning, and Transmission Electron Microscopies. The samples were treated by grinding tests following the Italian guidelines Decrees 14/5/96 and 152/2006 for the determination of the Release Index (RI), i.e., the fiber amount released through controlled crushing tests. The fine-grained powder released during the tests was analyzed by quantitative Fourier transform infrared spectroscopy (FTIR) to determine the variety and the amount of released fibers and to assess the potential hazard of the different serpentinite samples. Results indicate that the amount of released fibers is mostly related to serpentinite deformation, with the highest RI values for cataclastic and foliated samples, typically characterized by widespread occurrence of fibrous veins. Conversely, massive pseudomorphic serpentinite revealed a very low RI, even if their actual chrysotile content is up to 20–25%. Based on our original findings from the RI results, a preliminary investigation of the outcrop at the mesoscale would be of primary importance to obtain a reliable hazard assessment of NOA sites, allowing the primary distinction among the different serpentinites lithotypes and the effective fiber release.

Prediction of Freezing Air Temperature Distribution in the Entire Railway Tunnel According to Tunnel Length and Outside Air Temperature

Prediction of Freezing Air Temperature Distribution in the Entire Railway Tunnel According to Tunnel Length and Outside Air Temperature

Evaluation of an innovative, open-source and quantitative approach for the kinematic analysis of rock slopes based on UAV based Digital Outcrop Model: A case study from a railway tunnel portal (Finale Ligure, Italy)

This paper presents a novel, cost-effective method for a rapid and quantitative characterization of discontinuities in fractured rock cliffs using Unmanned Aerial Vehicle-derived Digital Outcrop Models (DOMs). The proposed workflow combines manual extraction of discontinuity data from the DOM with a kinematic analysis using an automated algorithm (ROKA), which upgrades and renews the traditional Markland's test. The case study, a designed railway tunnel portal in NW Italy (Finale Ligure) demonstrates the advantages and limitations of this approach compared to current methods. Manual mapping is compared with (semi-)automatic extraction of discontinuity data from the DOM and validated with field-based scan lines. The results show that in complex geological settings, manual mapping provides more statistically robust and geologically reliable measurements of discontinuity orientation, validated by the user's expertise. Traditional stereographic approaches in kinematic analysis are limited in characterizing spatially variable slopes and discontinuity networks, providing only generic estimations of unstable slope surfaces and discontinuity intersections. This limitation is overcome by new algorithms that incorporate 3D spatial relationships of both the discontinuity network and the rock slope, resulting in a more accurate and site-specific kinematic characterization of the rock cliff, emphasized by 3D visualizations of the critical planes and potential rock failure volumes. The new approach significantly impacts the time, effort, and cost of the engineering projects, allowing to quantitatively define the potential unstable areas with a fast analysis. The Authors stress the importance of integrating digital workflows with comprehensive field-based characterizations of the local litho-stratigraphic and structural setting to effectively utilize large datasets and partially automated procedures.

Three-dimensional trajectories of irregular-shaped tunnel lining fragments in the flow environment caused by high-speed trains

High-speed railway tunnel lining fragments can cause collisions with trains and track blockages, severely affecting train operation. When a train passes through a tunnel where lining fragment is likely to occur, the train wind effect may significantly affect the trajectory of the lining fragment, making the location where the lining fragment is difficult to predict. For safety purpose, this study aims to analyze the impact of the initial circumferential position and shape of irregular-shaped lining fragments on their aerodynamic performance. Using on-site scanning and mathematical statistical methods, the shape characteristics and probability distribution of actual lining fragments in the tunnel are obtained. The aerodynamic behavior of irregular-shaped lining fragments with different initial positions and three typical aspect ratios (ARs) are investigated based on the overset grid method and the dynamic fluid–body interaction model framework as a high-speed train passes. The study found that the most representative lining fragments with an AR of three have a mass of 1.5 kg and are located 2.5 m from the tunnel centerline. The flight behavior of lining fragments shows distinct three-dimensional features, with both translation and rotation significantly affected by the aerodynamic effects of the train and the geometric shape of the fragments. The longitudinal and lateral translational distances of lining fragments at the top of the train decrease as their initial position moves further from the tunnel's centerline. With an increase in AR, both the longitudinal and lateral flight distances and average flight velocities of the fragments increase. The macroscopic flow field within the tunnel directly influences the motion characteristics of the lining fragments. Complex flow separation and circulation phenomena near the fragments result in uneven pressure differences acting on the smooth and rough surfaces of the lining fragments, causing irregular motion. The conclusions of this study provide a theoretical basis for assessing and preventing the impact of lining fragments on the operational safety of trains.

Research on Rock Support Technology of Railway Tunnels Based on Geomechanical Model Tests

Research on Rock Support Technology of Railway Tunnels Based on Geomechanical Model Tests

OPTIONS SELECTION AND IMPACT STUDY OF INTERCITY RAILWAY TUNNEL CONSTRUCTION UNDER AIRPORT INTERZONE

The selection of tunnel construction program for intercity railroad tunnel under the airport must consider the limitations of environmental conditions and the scale of tunnel construction, and the impact of construction on the airport must be controlled within safe limits. Combined with the intercity rail transit tunnel project through the airport area surrounding environment and engineering geological conditions, the use of theoretical analysis, numerical simulation and other methods, comprehensive navigation, technology, construction period, cost, construction impacts and other aspects of the comparative analysis of the tunnel construction method of open excavation method and shield method, the results show that: (1) Due to the soft soil and groundwater in the tunnel excavation area, the risk of open excavation is greater, while the shield method is more suitable for longer silty soil tunnels without affecting the navigation, accordingly, the shield tunnel construction is more suitable for the tunnel construction under the airport. (2) Open excavation method has the shortest construction period to meet the requirements of rail transit, the unit cost is between 1 and 2 shield machines, and the total cost is close to 2 shield machines; for lower total cost, choose 1 shield machine, for shortening the construction period, choose 2 shield machines. (3) The maximum ground settlement caused by shield tunneling construction is 20mm, the maximum vertical differential settlement perpendicular to the tunnel is 2.8cm, and the maximum differential settlement is 0.93 ‰. On the one hand, it meets the requirements of airport settlement control, and on the other hand, it has little impact on the vertical connecting road and west station apron, and will not affect the opening of the airport runway and the operation of the terminal.

Analysis of visual and acoustic measures for self-evacuations in road tunnels using virtual reality

Emergency fire situations in tunnels can be especially dangerous when occurring in long underground or subsea tunnels, particularly when evacuation on foot is the only alternative. This paper presents the results from a study comparing different visual and acoustic measures to facilitate efficient and safe emergency evacuation and their effect on people's self-rescue behaviour in response to a tunnel fire. Eighty-one participants evaluated seven different scenarios in virtual reality with or without visual and acoustic supporting measures (i.e. signs, lights, acoustic beacons) to find their way to emergency doors. Objective behavioural data, such as orientation, and walking speed, were collected. The results suggest that the distance between the emergency doors increases uncertainty and affects the time to self-rescue significantly, with four times longer times for 500 m than 250 m between doors. Additionally, the use of continuous guiding lights positively supported orientation and walking speed, with 97 % of the participants finding their way and showing a reduction of time to reach the emergency door of 10–20 s. The study underscores the importance in the proper visual and acoustic evacuation measures for the wayfinding of emergency exits, improving self-rescue of people.

Research on wavelet packet energy entropy extraction method for acoustic signal of tunnel lining cavity

Abstract Tunnel lining cavity is a common disease in high-speed railway tunnels, which seriously affects the safe operation of the line.At present, the commonly used method is manual knocking inspection, but it relies on manual judgment, subjective factors have great influence, and there are errors. This paper proposes a feature extraction method of acoustic vibration signal of tunnel lining cavity based on wavelet packet energy entropy and uses wavelet packet energy entropy to realize the identification of cavity defects.The full-scale simulation model of tunnel with a radius of 6m was constructed by COMSOL and different cavity conditions were set up. The wavelet packet energy entropy characteristics of acoustic signals were extracted and analyzed. The mapping relationship between cavity depth and cavity size and wavelet packet energy entropy was explored. The wavelet packet energy entropy and frequency band distribution characteristics were extracted to realize the identification of cavity defects.The local model which can characterize the whole tunnel is designed and the embedded defects are verified by experiments. The results show that the wavelet packet energy entropy can be used as the identification feature of tunnel lining cavity defects. When the wavelet packet energy entropy is less than 2.53, the existence of tunnel lining cavity defects is characterized.When the wavelet packet energy entropy is in the range of 2.53-2.94, it characterizes the existence of the transition boundary between tunnel lining cavity defect and no disease.This index can be used to realize the rapid and effective identification of cavity defects.

Prediction of icicles on lining surface in high-speed railway tunnel in severe cold region based on the characteristics of daily temperature fluctuation

：Icicles in high-speed railway tunnels in cold regions pose a serious threat to operational safety. Tunnels with long lengths and large sizes require manual inspection, generating considerable work and expense for operation management. To reduce the workload of icicle inspection and guide manual deicing, a growth and development model of tunnel icicles was developed based on a tunnel icicle simulation system, and a tunnel lining icicle prediction and warning system was established, that provides guidance for deicing by predicting the range and development degree of tunnel icicles. The icicle simulation test shows that there is an obvious division of icing and non-icing area in the tunnel, and the boundary of the division is −5 °C. There is an optimum temperature range for the growth and development of icicle in tunnels. Under daily temperature fluctuations, the icicles grow back after being removed. A model for degree of icicle development was established. The degree of icicle development is affected by leakage flow, daily fluctuation amplitude of temperature, and daily average temperature. The smaller the daily temperature fluctuation and the closer the daily average temperature to the optimum temperature for icicle growth, the better the development of icicle. Based on the icicle development model, a prediction and warning method for icicles in tunnel was developed. Based on the network of instruments measuring and reporting temperature, the real-time temperature distribution of the tunnel was obtained, combined with the leakage distribution and volume in the tunnel, the icicles section and the icicles severity of the tunnel were obtained by analyzing the icicle growth model embedded in the system, providing guidance for the inspection of icicles in the tunnel. A comparison shows that the icicle prediction and warning system can reduce the walking inspection workloads by half.

Review of the experience in utilising waste heat from the metro

The exhaustibility of traditional fossil energy sources is leading to the increasing use of unconventional energy sources. One of the most promising areas of alternative energy is the use of low-potential ground energy to heat buildings and structures for various purposes using a heat pump. The subway generates a significant amount of heat, especially when trains are braking, stopping on platforms and picking up speed when they start moving from the station. Thus, to combat the rise in temperature in tunnels and stations, a complex ventilation system is designed, including shafts, fans, and under-platform exhaust. In modern Ukrainian subways, the ventilation system is designed to cope with the rising temperatures in tunnels and stations. This traditional approach results in high energy consumption for running fans and ignores the possibility of using the extracted heat above ground in buildings. Techniques such as lining underground railway tunnels with heat exchanger segments, installing a heat exchanger in a subway ventilation shaft, installing geothermal heat pumps next to a subway tunnel, installing energy piles, energy baffle walls, energy platforms, and introducing absorption pipes into tunnel segments can provide an alternative solution to cool tunnels and the surrounding ground, and transfer the resulting heat to neighbouring buildings for heating. This would also have the benefit of reducing energy consumption for tunnel ventilation. This article discusses the possibility of using waste heat from underground railway systems as a source of low-potential energy to provide heat to, for example, adjacent buildings. Various technologies for utilising waste heat from underground railway tunnels that have already been implemented or whose models are technically and economically feasible are presented.

Efficient Mako Shark-Inspired Aerodynamic Design for Concept Car Bodies in Underground Road Tunnel Conditions.

The automotive industry continuously enhances vehicle design to meet the growing demand for more efficient vehicles. Computational design and numerical simulation are essential tools for developing concept cars with lower carbon emissions and reduced costs. Underground roads are proposed as an attractive alternative for reducing surface congestion, improving traffic flow, reducing travel times and minimizing noise pollution in urban areas, creating a quieter and more livable environment for residents. In this context, a concept car body design for underground tunnels was proposed, inspired by the mako shark shape due to its exceptional operational kinetic qualities. The proposed biomimetic-based method using computational fluid dynamics for engineering design includes an iterative process and car body optimization in terms of lift and drag performance. A mesh sensitivity and convergence analysis was performed in order to ensure the reliability of numerical results. The unique surface shape of the shark enabled remarkable aerodynamic performance for the concept car, achieving a drag coefficient value of 0.28. The addition of an aerodynamic diffuser improved downforce by reducing 58% of the lift coefficient to a final value of 0.02. Benchmark validation was carried out using reported results from sources available in the literature. The proposed biomimetic design process based on computational fluid modeling reduces the time and resources required to create new concept car models. This approach helps to achieve efficient automotive solutions with low aerodynamic drag for a low-carbon future.

Multiscale Seismic Monitoring in the Bedretto Underground Laboratory for Geosciences and Geoenergies (BULGG)

Abstract The Bedretto Underground Laboratory for Geoenergies and Geosciences (BULGG) is located in south-central Switzerland in the middle of a 5.2-km-long tunnel, which connects the Bedretto valley to the Furka railway tunnel. BULGG is a multidisciplinary laboratory that facilitates experiments and research across various fields. From a seismological perspective, a dense seismic network is deployed that allows real-time monitoring of both natural and induced seismicity occurring in the tunnel and the surroundings. In addition, a multilevel monitoring approach during experiments leads to the generation of real-time high-resolution earthquake catalogs issuing event-based alerts and is the input for a simple traffic light system (magnitude and/or ground-motion based), which provides essential information for the advanced traffic-light system (probabilistic approach). We have set up two separate real-time monitoring systems that monitor the background seismicity, as well as injection experiments, with both systems built on the SeisComP framework. The background monitoring, serving as the backbone network, includes broadband sensors at the surface and along the tunnel, as well as strong-motion sensors and high-frequency geophones along the tunnel and in boreholes. The sampling rate is divergent and depends on sensor type and proximity to faults (200–2000 Hz). Acoustic emission sensors and high-frequency accelerometers sampled at 200 kHz constitute the experimental setup that locates in multiple experimental volumes, which include fluid injections, extractions, and tunneling activities. All sensors transmit real-time data to a common server (SeedLink), which serves multiple clients for processing, real-time visualization, archiving via SeisComP, and risk control via dedicated software. A standardized workflow is applied to both background and experimental monitoring, encompassing automatic picking, automatic phase association and location, and magnitude estimation. Advanced methods are implemented in real time that include double-difference relocation and earthquake detection based on waveform cross correlation. BULGG provides a unique environment to implement novel methods in observational and network seismology across scales.

Engineering geological and geotechnical evaluation of Sathya Sai Prasanthi Nilayam railway tunnel, Andhra Pradesh, India

Detailed engineering geological investigations were carried out for a railway tunnel which was constructed more than two decades ago. 3D engineering geological mapping was carried out using Brunton Compass and Total Station Surveying instruments in 1:100 scale. Coarse-grained pink and grey granite, hornblende-biotite gneiss and dolerite dyke of Archaean age and Lower Proterozoic age were mapped. Rock mass was intersected by sub-horizontal, inclined, and vertical joint sets, which were continuous and persistent, smooth, and planar with thick filling of decomposed and crushed sheared material or with thin coating of clay material. Based on the Q-system, rock mass was classified into different classes. On the basis of large-scale engineering geological mapping and Norwegian Method of Tunnelling, a support system was recommended which includes rock bolt, fibre reinforced shotcrete, grouting and reinforced ribs of sprayed concrete and the same is implemented by the agency. As per the best knowledge of the authors, reinforced ribs of sprayed concrete are first time used for transportation tunnels in India and it will be more effective if it will be compared with ISMB or Lattice Girder.