Highway Tunnel Construction Research Articles

The Effect of Distance between Jet Fans on Gas Transport, Energy Conservation, and Emission Reduction in Long Highway Tunnels

With the rapid development of the national economy, China’s transportation industry is experiencing accelerated development, and, at the same time, the number of long tunnels is constantly increasing. In order to examine the influence of jet fan spacing on gas transport law during the construction of long highway tunnels, this study used the Baima Highway Tunnel in Sichuan as an engineering prototype and established a numerical tunnel ventilation model based on Fluent numerical simulation software. The gas transport characteristics of jet fans in tunnels at different spacings (200 m, 400 m, 600 m, and 800 m) were studied. The results showed that with the increase in jet fan spacing (200 m, 400 m, 600 m, and 800 m), the gas concentration at the tunnel face showed a trend of decreasing and then increasing. Moreover, by analyzing the gas distribution cloud map and the wind flow line diagram, it was determined that the ventilation system effect was the best when the jet fan spacing was 600 m, which met the requirements of a gas concentration of less than 0.5% at the tunnel face and a minimum wind speed of 0.25 m/s. At the same time, according to the optimal spacing for the optimization of the site ventilation system, it was observed that after the ventilation was stabilized (after 600 s), the minimum value of the gas concentration in the left and right tunnel holes diminished from 0.38% to 0.31% and from 0.41% to 0.31%, with rates of reduction of 18.42% and 24.39%, respectively. This indicated that after optimizing the ventilation system at the tunnel site, the concentration significantly decreased compared with before the optimization. Moreover, when the jet fan spacing was 600 m compared with 200 m and 400 m, the annual energy savings were 1900.8 MW·h and 950.4 MW·h, respectively. The research results clarified the optimal layout parameters of jet fans in the Baima Highway Tunnel, providing a reference for the rational layout of jet fans in long-distance tunnels. In addition, the results of this study provide an important theoretical basis for the gas prevention and safe construction of long highway tunnels. Furthermore, this study contributes to research in energy conservation, emission reduction, and sustainable development of energy in the ventilation process during tunnel construction.

A morphology-Euclidean-linear recognition method for rebar point clouds of highway tunnel linings during the construction phase

PurposeLaser point clouds are a 3D reconstruction method with wide range, high accuracy and strong adaptability. Therefore, the purpose is to discover a construction point cloud extraction method that can obtain complete information about the construction of rebar, facilitating construction quality inspection and tunnel data archiving, to reduce the cost and complexity of construction management.Design/methodology/approachFirstly, this paper analyzes the point cloud data of the tunnel during the construction phase, extracts the main features of the rebar data and proposes an M-E-L recognition method. Secondly, based on the actual conditions of the tunnel and the specifications of Chinese tunnel engineering, a rebar model experiment is designed to obtain experimental data. Finally, the feasibility and accuracy of the M-E-L recognition method are analyzed and tested based on the experimental data from the model.FindingsBased on tunnel morphology characteristics, data preprocessing, Euclidean clustering and PCA shape extraction methods, a M-E-L identification algorithm is proposed for identifying secondary lining rebars in highway tunnel construction stages. The algorithm achieves 100% extraction of the first-layer rebars, allowing for the three-dimensional visualization of the on-site rebar situation. Subsequently, through data processing, rebar dimensions and spacings can be obtained. For the second-layer rebars, 55% extraction is achieved, providing information on the rebar skeleton and partial rebar details at the construction site. These extracted data can be further processed to verify compliance with construction requirements.Originality/valueThis paper introduces a laser point cloud method for double-layer rebar identification in tunnels. Current methods rely heavily on manual detection, lacking objectivity. Objective approaches for automatic rebar identification include image-based and LiDAR-based methods. Image-based methods are constrained by tunnel lighting conditions, while LiDAR focuses on straight rebar skeletons. Our research proposes a 3D point cloud recognition algorithm for tunnel lining rebar. This method can extract double-layer rebars and obtain construction rebar dimensions, enhancing management efficiency.

Design of Rock Support in Hard and Layered Rock Masses Using a Hybrid Method: A Study Based on the Construction of the New Skarvberg Tunnel, Norway

AbstractHard rock formations with layered, anisotropic geological structures are rather common in Norway. The design of tunnel rock support under such ground conditions has been traditionally done with an empirical approach and assisted with engineering rock mass classification. In most cases, rock stability has been achieved with the use of fiber-reinforced sprayed concrete combined with rock bolts, sometimes supplemented with ribs of reinforced sprayed concrete (RRS) and bolt spiling. However, the discontinuous character and more complex ground behavior of layered rock can lead to design challenges as experienced during the construction of the new Skarvberg highway tunnel in Northern Norway. A significant portion of the tunnel exhibited consistent overbreak, delamination problems and a tunnel failure. In this article, the ground behavior and rock support performance at different locations of the tunnel are investigated to find a basis for design optimization of rock support under similar ground conditions. For this purpose, a thorough site investigation program was carried out, which formed the basis for further assessments and analyses with a hybrid design methodology and the numerical code UDEC (Itasca). As a result, the main challenges of classification systems to capture ground behavior and derive optimal support design in layered rocks were identified. As such, this study has investigated design optimization possibilities, which resulted in the development of, among others, a specific ground behavior classification for layered grounds and a new, optimized RRS-support concept for layered rock masses of very poor quality (e.g., Q ~ 0.1–1).

Highway tunnel safety detection and management

Highway tunnel is an important part of highway engineering, and its safety detection and management play a pivotal role in the construction and maintenance process of the whole project. However, due to the particularity of the tunnel itself, the engineering quality is difficult to guarantee, and there are many safety risks. With the continuous development of China's traffic industry, there are more and more highway tunnel construction, so safety detection and management is particularly important.

Impact analysis of dust evolution pattern and determination of key ventilation parameters in highland highway construction tunnels

In order to study the influence of ventilation parameters on the ventilation of plateau highway construction tunnels, a highway tunnel construction section in Yunnan is taken as the research background, and Fluent software is used for simulation. The results of the study show that: under the conditions of press-in ventilation, the wind speed in the center of the vortex area in the wind flow field is smaller than the wind speed in the surrounding area, and with the diffusion of the flow field, the average wind speed in the tunnel section gradually decreases, and ultimately stabilizes at the level of 0.5 m/s. After blasting, the dust mass concentration on the return side of the tunnel is higher than that on the duct side. Dust with a particle size of 30 μm or more settled rapidly within 100 m from the boring face, while dust with a particle size of 30 μm or less gradually diffused outward under the action of the wind flow. In the vicinity of the tunnel boring face, reducing the distance from the air outlet to the boring face and increasing the air velocity can improve the dust removal effect. This conclusion can provide theoretical basis and certain guidance for the evolution of dust and dust prevention in the tunnel construction process in plateau area.

Optimization of blasting construction and vibration control technology of multi arch tunnels without central partition walls

The construction technology for multi arch tunnels without central partition walls is a new design method for multi arch tunnels. The construction technology of multi arch tunnels without central guide tunnels eliminates side and central guide tunnels, which not only accelerates construction progress but also ensures construction quality and safety. The excavation and support of the rear tunnel of a double-arch tunnel without a central partition are crucial to ensuring the overall stability of the tunnel structure. A combination of manual mechanical excavation and blasting excavation in some areas was used in the excavation and construction of the rear tunnel of the Chenjiachong Tunnel on the Chuyao Expressway in Yunnan in addition to damping materials and measures in the lining of the front tunnel, ensuring the safe excavation of the rear tunnel and the prevention of the lining of the front tunnel from cracking because of earthquakes, The on-site vibration monitoring results of the tunnel indicate that this technology has achieved good results. Overall, the optimized construction technology without a central partition greatly shortens the construction period and improves economic benefits. The construction method is simple and feasible and can be flexibly selected according to the surrounding rock conditions. This study can provide a reference for the construction of other highway tunnels in mountainous areas.

Prediction and optimization of adverse responses for a highway tunnel after blasting excavation using a novel hybrid multi-objective intelligent model

It is one of the main challenges of modern traffic engineering to monitor and control the adverse response of highway tunnels after blasting excavation. To that end, this paper proposes a novel hybrid multi-objective intelligent model to predict and optimize four adverse responses including tunnel roof settlement (TRS), linear overbreak (LO), underbreak area (UA), and the maximum block size (MBS) based on a case highway tunnel. This model is assembled by the support vector regression (SVR) and a multi-objective golden jackal optimization (MOGJO) algorithm. 95 monitored data after tunnel blasting containing 11 features of four categories are used to train and test the models. Other five classical intelligence models are also developed to compare the predictive performance of the proposed model. The results of model development indicate that the proposed model has the optimal predictive performance among all models when the ratio of training set to test set is 8: 2. The calculation results of performance evaluation indices (determination coefficient (R2) and root mean square error (RMSE)) demonstrate that the proposed MOGJO-SVR model is the best model for predicting four tunnel adverse responses among all models, i.e., TRS (R2: 0.9837; RMSE: 0.5591), LO (R2: 0.9711; RMSE: 4.5022), UA (R2: 0.9800; RMSE: 0.3803), and MBS (R2: 0.9535; RMSE: 5.9248). Besides, the model interpretation results based on the Shapley additive explanations (SHAP) method show that the contribution of blasting and explosive parameters to the adverse responses is significant. Then, a visualization procedure is generated to optimize the adverse responses for different tunnel excavation designs in real time. This work guides the prediction and control of adverse responses in highway tunnel construction.

Real-Time Monitoring Technology for Carbon Emissions in Mountain Expressway Tunnel Construction

The complexity of tunnel construction places it in a position of great importance in the overall construction of highways, and the carbon emissions generated during its construction also account for a large portion. The report of the 20th National Congress of the Communist Party of China pointed out the need to "actively and steadily promote carbon peaking and carbon neutrality." As one of the main contributors of carbon emissions, the transportation industry needs to actively increase its efforts to reduce emissions, innovate ways to reduce emissions, and not overlook any sources of carbon emissions. This article relies on the Linshuang Expressway project, which combines theoretical calculation logic with information and Internet of Things technology to complete the construction of a real-time monitoring system for carbon emissions during tunnel construction in mountainous areas. Through this system, construction carbon emissions can be visualized and monitored in real-time, providing reliable data support for emission reduction in tunnel construction, and providing technical references for promoting low-carbon, clean, and green highway tunnel construction, in order to further support the development of a strong transportation country.

Intelligent framework for multiple-attribute decision-making under probabilistic neutrosophic sets and its applications

Highway engineering itself is a large-scale project with high construction safety requirements, involving multiple construction safety factors. In order to better ensure the orderly development of highway tunnel construction, it is necessary to strengthen construction safety evaluation. The construction safety management evaluation of highway engineering is viewed as the multiple-attribute decision-making (MADM) issue. In this paper, an extended probabilistic neutrosophic number TOPSIS (PNN-TOPSIS) method is established for construction safety management evaluation of highway engineering. The PNN-TOPSIS method integrated with CRITIC method in probabilistic neutrosophic sets (PNSs) circumstance is applied to rank the optional alternatives and a numerical example for construction safety management evaluation of highway engineering is used to proof the newly proposed method’s practicability along with the comparison with other methods. The results display that the approach is uncomplicated, valid and simple to compute.

Investigation of cracking mechanism of the first tunnel lining during double-arch tunnel construction

To solve the engineering problem of the first tunnel lining cracking caused by the second tunnel construction of double-arch highway tunnels, a research method combining distributed optical-fibre monitoring, inversion analysis and numerical simulation that can reflect lining cracking was presented. Optical fibres were laid on opposite sides of the steel arches inside the first tunnel lining. Embedded optical-fibre monitoring was conducted continuously during the second tunnel driving. Based on the fibre-optic strain profile, the lining cracking was deduced and warned in time. The mechanical behaviour of the steel arch was investigated by the inversion analysis, which took into consideration the integrated impact of axial force and flexural moment. A two-dimensional (2D) load-structure method–based numerical model was established, considering the influence of different load distributions in each construction condition. The total strain rotating crack constitutive model was applied to reflect the cracking behaviour of concrete lining in the simulation, and the model was calibrated and verified in the laboratory. Comparative analysis between the simulated strain distribution and the distributed optical-fibre monitoring results was carried out. The deformation mode and crack distribution of the lining were analysed. The cracking mechanism was explained. Specifically, the second tunnel construction led to the loading at the top of the middle partition wall and the release of rock pressure in the first tunnel. Under these load changes, the secondary lining of the first tunnel cracked on the inner side of the top of the middle partition wall owing to tension, and compression-bending failure occurred near the right arch foot. Finally, the influence of the parameters on the lining force was analysed, and a construction optimisation scheme was proposed.

Study on the Vehicle-Induced LTAS Law of the Tunnel in Diatomite Area

Due to the weak characteristics of diatomite, excessive settlement may happen under long-term dynamic vibration load and affect the later operation of trains, while there are few researches on the dynamic response of highway tunnel in diatomite yet. Taking the Feifengshan high-speed railway tunnel project as the study case, the impact of different reinforcement parameters on long-term accumulated settlement (LTAS) rule of the highway tunnel in the diatomite area under train load is studied by numerical simulation and layer-wise summation method (LWSM). The results reveal that tunnel LTAS in diatomite area mainly appears in the first and the second years of the running stage of train, and the LTAS in these two years accounts for half of the ultimate stable LTAS. The longer the pile length (PL) and the larger the pile diameter (PD), the smaller the dynamic deviatoric stress (DDS) and LTAS. However, when pile lengths or pile diameter exceed a certain range (PL = 16 m or the PD = 150 mm), the control effect of increasing the PL and PD on the LTAS of the tunnel in diatomite is no longer significant. This indicates that there exist preferred values of the PL and PD. There are few cases of the construction of highway tunnels in the diatomite area before the engineering project in this paper yet. Hence, this paper will provide a reference to the construction of the foundation reinforcement scheme of high-speed railway tunnels in diatomite layer.

Infrastructure-Based Digital Twins for Cooperative, Connected, Automated Driving and Smart Road Services

Driving requires continuous decision making from a driver taking into account all available relevant information. Automating driving tasks also automates the related decisions. However, humans are very good at dealing with bad quality, fuzzy, informal and incomplete information, whereas machines generally require solid quality information in a formalized format. Therefore, the development of automated driving functions relies on the availability of machine-usable information. A digital twin contains quality controlled information collected and augmented from different sources, ready to be supplied to such an automated driving function. An information model that describes all conceivably relevant information is necessary. To this end, a list of requirements that such an information model should meet is proposed and each requirement is argued for. Based on the anticipated services and applications that such a system should support, a collection of requirements for system architecture is derived. Information modeling is performed for selected relevant information groups. A system architecture has been proposed and validated with three different implementations, addressing several different applications to support decisions at a highway tunnel construction site in Austria and throughout the Test Bed Lower Saxony in Germany.

Failure analysis and countermeasures of highway tunnel crossing fault fracture zone in coal-bearing strata: A case study

Collapse occurs frequently during the construction of highway tunnel crossing fault fracture zone in coal-bearing strata. This paper presents a case study on the failure mechanism and treatment measures of the collapse of a tunnel. In-situ investigation indicates that the continuous looseness of surrounding rock caused by the crushing of coal seam is the main cause of collapse. The uniaxial compressive strengths of coal and rock was subsequently determined based on point load test. The in-situ stress measurement results show that the tunnel is in the extremely high stress zone. In addition, the collapse mechanisms were analyzed in aspects of in-situ stress, groundwater, surrounding rock mechanical properties and geology. The countermeasures of grouting and support strengthening were taken to improve the stability of surrounding rock. The effects of countermeasures were discussed by analyzing monitoring data. The lesson learned from the collapse case study can provide a reference for similar tunnels.

Stability Analysis and Construction Parameter Optimization of Tunnels in the Fractured Zone of Faults.

In order to improve the construction method of highway tunnel fault, improve the excavation level, improve the construction efficiency, reduce the project cost, and shorten the construction period, so as to find a specific road, this paper puts forward the research method of tunnel stability analysis and construction parameter optimization in the fault fracture zone. First, this paper analyzes the specific geographical and geological environment of the construction site. Second, this paper compares and analyzes the effects of the drilling and blasting method and full-face tunnel boring machine (TBM) in construction and further analyzes the surrounding rock deformation, over excavation, and under excavation, as well as the range of loose circles when the surrounding rock is stable. Then, this paper discusses the minimum smooth blasting parameters under these conditions. Finally, the actual blasting effect of tunnel construction is tested and the optimization algorithm model of tunnel fault drilling and blasting parameters is established. The results show that the proposed optimization model of drilling and blasting construction parameters for highway tunnel faults based on the Support Vector Regression (SVR) algorithm combined with a genetic algorithm (GA) has a short calculation time and high parameter optimization accuracy. It is very feasible to optimize the construction parameters of the fault drilling and blasting method, which can greatly improve the construction efficiency, carry out the detailed simulation, reduce the cost, and increase safety. In summary, it has a certain reference significance for the optimization of highway tunnel construction and future research by drilling and blasting method under complex geological conditions in my country.

Influence of Lower Double-Track Tunnel Spacing on the Stress and Deformation Characteristics of Upper Tunnel in Double-Level Condominium Tunnels

The open-cut tunnels in Aixi Lake, Nanchang, are constructed in a condominium form of highway tunnel and subway tunnel, which are the first superimposed double-level tunnels in China. The scientific problems faced by this new structure form have attracted the attention of engineers and researchers. If this structure form can be reasonably used, it can reduce the repeated excavation of the ground and reduce the impact of highway tunnel construction on subway tunnels. It is of great guiding significance to study the influence of the spacing between lower double-track subway tunnels on the stress and deformation characteristics of the upper highway tunnel. Based on the model test, the deformation, axial force, bending moment, and earth pressure of the upper highway tunnel are studied. The results show that the maximum displacement of upper tunnel floor can be reduced by 30% when the spacing of the lower tunnel makes the center line of the lower single tunnel coincide with the quadripartite line of the upper tunnel. Horizontal spacing between lower double-track tunnels significantly influences the bending moment of upper tunnel floor but hardly influences the axial force of the upper tunnel floor. Considering the influence of lower tunnel spacing on the earth pressure of the upper tunnel floor, the spacing of the lower tunnel should not exceed 50% of the section width of the upper tunnel.

Practical Research on Grouting Reinforcement Technology in Highway Tunnel Construction

Practical Research on Grouting Reinforcement Technology in Highway Tunnel Construction

Study on the Application of Grouting Reinforcement Technology in Highway Bridge and Tunnel Construction

Study on the Application of Grouting Reinforcement Technology in Highway Bridge and Tunnel Construction

Process Control of Highway Tunnel Construction Technology Quality

Process Control of Highway Tunnel Construction Technology Quality

Dynamic risk evaluation method for collapse disasters of drill-and-blast tunnels: a case study.

The tunnel collapse is one of the most frequent and harmful geological hazards during the construction of highway rock tunnels. As for reducing the occurrence probability of tunnel collapse, a new dynamic risk assessment methodology for the tunnel collapse was established, which combines the Cloud model (CM), the Membership function, and the Bayesian network (BN). During the preparation phase, tunnel collapse risk factors are identified and an index system is constructed. Then, the proposed novel assessment method is used to evaluate the probability of tunnel collapse risk for on-site construction. The probability of tunnel collapse risk in the dynamic process of construction can provide real-time guidance for tunnel construction. Moreover, a typical case study of the Yutangxi tunnel is performed, which belongs to the Pu-Yan Highway Project (Fujian, China). The results show that the dynamic evaluation model is well validated and applied. The risk value of tunnel collapse in a construction cycle is predicted successfully, and on-site construction is guided to reduce the occurrence of tunnel collapse. Besides, it also proves the feasibility of the dynamic evaluation method and its application potential.

Influence of Lining Design Parameters on the Greenhouse Gas Emissions of Chinese Highway Tunnel Construction

To realize low-carbon design for tunnel construction, the authors explored the relationship between tunnel design and greenhouse gas (GHG) emissions. This study proposed typical design models of Chinese highway tunnels based on the lining design specifications and engineering design cases. The research modified the GHG emission calculation method based on the standard quota system. The marginal GHG emissions caused by a change of design parameters of tunnel lining were determined. The results show that the emissions from shotcrete, concrete arch wall, system bolts, and steel frames are sensitive to the change of design parameters, while steel mesh is not. As the design thickness increases, the emissions of the concrete arch wall, inverted arch, and shotcrete increase approximately linearly. The emission distributions of system bolts and steel frames under different spacing are given. Under the same longitudinal spacing condition, the emission ratio of I18 and I16 steel frames is 1.197, and that of I16 and I14 steel frames is 1.316. By defining the marginal emissions caused by the change of design parameters, this study carried out basic work for highway tunnel low-carbon designs. The research is of strategic significance for achieving energy conservation and emission reduction in the tunnel industry.