Tunnel In China Research Articles

Application and Challenges of BIM Technology in China's Integrated Utility Tunnels

In the context of rapid urbanization, integrated utility tunnels present an innovative solution by consolidating various pipelines into a unified underground system, improving construction efficiency and urban management. This paper explores the role of Building Information Modeling (BIM), a breakthrough technology that enhances project design, simulation, and construction efficiency through digital modeling. BIM technology is optimizing utility tunnel construction by enabling better planning, monitoring, and collaboration through 3D and 4D modeling. Using a PESTEL analysis framework, this study evaluates BIM's application in integrated utility tunnels in China and its potential for advancing the digital transformation of urban infrastructure. The research reveals how BIM can enhance the informatization and intelligence of utility tunnels and discusses the future opportunities and challenges for its expansion in China's urbanization efforts.

Study on the Susceptibility of Steel Arches with Letting Pressure Nodes Based on Incremental Dynamic Analysis

When soft rock tunnels pass through fractured fault zones, they are particularly susceptible to extrusion and large-scale deformations, especially during seismic events. To address these challenges, this study introduces an innovative yield-support steel arch design featuring a circumferential letting pressure node at its core. This design delivers incremental support resistance within the deformation zone and a susceptibility curve is applied to evaluate the damage probability of the steel arch with a letting pressure node under seismic loading conditions. Measurements of the surrounding rock pressure and structural forces on the steel arch with the letting pressure node were conducted at the Baoshan Jewel Mountain Tunnel in China. The field experiment results revealed a 23% reduction in the surrounding rock pressure and an 11% decrease in the internal forces of the support structure. These findings demonstrate the successful application of the letting pressure node-supported steel arch in mitigating large deformations in soft rock environments. Additionally, using finite element software ANSYS 2022, a seismic time-history analysis was conducted, employing the relative deformation rate of the letting pressure node steel arch as the damage index and the peak ground acceleration (PGA) as the strength parameter to generate the incremental dynamic analysis (IDA) curve. According to the susceptibility curve derived from the incremental dynamic analysis, at the design ground motion level of 8 degrees, the letting pressure node steel arch has a 94% probability of exceeding its normal service life limit and experiencing damage. The findings of this study offer a novel approach to addressing large deformations in soft rock tunnels. The proposed susceptibility curves for steel arches with letting pressure nodes provide a robust foundation for predicting the damage probability of yielding support structures under seismic conditions.

An analytical solution to ground stresses induced by tunneling considering ground surface boundary conditions and gravity

Accurately predicting the stress distribution around the tunnel is crucial for designing safe and economical support systems. The stress distribution is closely related to the ground stress release induced by tunneling, as well as the initial gravity stress and boundary conditions. In this study, a two-dimensional analytical model considering the ground surface boundary conditions and gravity is presented to investigate the stress field around the tunnel. Then, a numerical model was developed to validate the proposed analytical model. Finally, parametric analyses were conducted, and the limitations of the load calculation method of the code for design of shield tunnel in China were discussed. The results indicate that: (a) Tunnel excavation induces stress redistribution in the soil, resulting in a soil arching effect around the tunnel. This arching effect causes nonlinear load changes around the tunnel. (b) The soil mass around the tunnel can be divided into undisturbed and disturbed zones. Above the tunnel, the disturbance range is C-2D(C and D represent the burial depth and the tunnel diameter), while below and on both sides of the tunnel, the disturbance ranges are 4D and 1.5D, respectively. (c) Once the stress release rate reaches 0.6, a combined arching effect zone, consisting of both major and minor principal stresses, is formed in the disturbance zone above and below the tunnel. (d) The load distribution pattern calculated by the code for design of shield tunnel in China is gourd-shaped, and this calculation method is insufficient for accurately evaluating the load around the tunnel. The research results can provide a reference for the design of the shield tunnel.

In-tunnel pollutant concentration measurement and ventilation control indexes for highway tunnels in mountainous area: A case study of no.1 Qinling tunnel, China

The pollutant concentration and hygiene standards in mountain tunnels are key factors determining the ventilation effectiveness of tunnel operation. Previous studies have mainly focused on the spatiotemporal distribution patterns of in-tunnel pollutants, while research on ventilation control indexes for pollutants in long mountain tunnels are relatively limited. Therefore, this paper aims to discussing the hygiene control indexes for operational ventilation of mountain tunnels. Field tests were conducted in the No.1 Qinling Tunnel of Xi'an to Han zhong Highway in China, and the distribution laws of traffic flow, wind speed, and concentrations of particulate matter (PM), carbon monoxide (CO), and nitrogen oxide (NOX) were on-site measured. The spatiotemporal distribution characteristics of pollutants in the long mountain tunnel were revealed, and the ventilation hygiene control indexes for harmful gases were calculated and compared to those of urban highway tunnels. The results show that the traffic volume of operational highway tunnels in mountainous areas of China is increasing rapidly, and the particulate matter emitted from diesel vehicle exhaust will pose a threat to the normal environmental quality in the tunnel. The average value of CO base emission factor in 2000 for the upline of No.1 Qinling tunnel was 0.0019 m3/(veh·km) by back-calculation, and the annual decline rate of CO in the ventilation design for mountain highway tunnels should be 6 %–8 % and revised every 8 years. It is recommended to consider the geographical location and traffic conditions of mountain tunnels when calculating the air demand required for diluting NO2. NOx has basically replaced CO as the primary pollutant with the most significant impact on human health in mountain tunnels. It is recommended that NOX be considered as the primary hygiene control indicator in the ventilation design of mountain tunnels in China. The pollutant distribution and ventilation control indexes of mountain and urban highway tunnels are quite different, which should be treated differently in engineering applications. The research results can provide a significant reference for ventilation design and environmental evaluation of highway tunnels in mountainous areas.

Zero-carbon tunnel: Concept, methodology and application in the built environment

Road tunnels are key components in the transportation infrastructure system, and plays a key role in the carbon emission. At present, the research on tunnel carbon emissions is still at an early stage, and its research target has not yet realized the transformation from low-carbon to zero-carbon. Therefore, this paper proposes the concept of the zero-carbon tunnel and introduces a methodology for zero-carbon tunnel design. This methodology includes defining the accounting boundaries of a zero-carbon tunnel, establishing a tunnel life-cycle carbon emissions assessment model, and verifying the zero-carbon tunnel. The methodology is applied to a road tunnel in China, to assess its carbon emission level and explore pathways to achieve zero-carbon status. Additionally, this paper discusses issues related to zero-carbon tunnels and explores future research prospects in this area. This study provides a reference for subsequent research on road tunnel carbon emissions.

Reform of deformation control technology for railway tunnels with squeezing surrounding rock: case study of the new and existing Wushaoling tunnels in China

Reform of deformation control technology for railway tunnels with squeezing surrounding rock: case study of the new and existing Wushaoling tunnels in China

Simultaneous Measurement of Strain and Displacement for Railway Tunnel Lining Safety Monitoring

This paper proposes a dual-parameter strain/displacement safety monitoring technology for railway tunnel lining structures. An integrated monitoring system with FBG (Fiber Bragg grating) and VDM (video displacement meter) components was used to monitor both the strain and deformation of the tunnel cross-section. Initially, a comprehensive experimental study was carried out using FBG strain sensors with temperature-compensated grating. The temperature-compensated grating was used to further improve the monitoring accuracy. The data show that the stability and accuracy were better than the traditional electronic strain sensor. Secondly, high-precision and multipoint monitoring of railway tunnel lining deformation was achieved by using VDM technology. Three months of case study results taken from the Gansu Railway Tunnel in China demonstrated a tunnel cross-section strain accuracy for microstrain and crown deformation at the submillimeter level, respectively. The technology provides a new high-precision way to monitor the condition of tunnel lining structures.

Innovative design and construction of a closure joint for inland-river immersed tunnels via dry-land construction methods: A case study of the Yuliangzhou tunnel in China

Closure joints constructed to fill the spaces between immersed tunnel elements or between the tunnel elements and adjacent cut-and-cover tunnels are crucial for the longitudinal stability of immersed tunnels and affect the overall cost and duration of tunnel construction. To avoid the obstruction of navigation and reduce the difficulty of constructing closure joints, dry-land construction methods have been widely applied to construct closure joints for inland-river immersed tunnels, in particular using procedures involving axial dry docks. However, the traditional dry-land construction method has many inherent drawbacks. For example, the construction of underwater large-scale reinforced concrete antiretreat structures involves many underwater works, complicated construction processes, long operation time spans and high costs. Based on the Yuliangzhou immersed tunnel in China, a new dry-land construction method for closure joints of inland-river immersed tunnels based on tunnel–soil interface friction was developed to address the abovementioned problems. Considering the adverse influences of back-silting sediment on tunnel–soil interface friction, large-scale laboratory and onsite shear tests were carried out to derive the interface friction coefficients between the tunnel element base slabs and prelaid pebble foundation beds. A composite concrete steel sandwich (CCSS) water-retaining system was designed and assembled to separate the water in the dry dock from the river course. A simplified analysis method based on numerical simulations for the determination of the equivalent horizontal thrust P applied to element ES caused by the dewatering of the axial dry dock was proposed. Based on horizontal antisliding stability analyses of the tunnel elements during the axial dry dock dewatering stage, equations for the key design parameters of the new dry-land construction method were established. Through examination of the static equilibrium of the tunnel elements in the tunnel longitudinal direction, temporary longitudinal displacement constraint (LDC) structures at the immersion joints were designed. Furthermore, the following key construction techniques for the new dry-land construction method were systematically designed: installation of a CCSS water-retaining system at the entrance of the axial dry dock, water sealing at contact gaps, installation of finish-rolled screw-thread (FRST) steel bars as the LDC structures at the immersion joints, and construction of rigid connections between tunnel element ES and the cut-and-cover tunnel. Finally, onsite observation of the deformation states of Gina gaskets and monitoring of the tensile forces of FRST steel bars at the immersion joints verified the successful implementation of the new dry-land construction method, supporting the use of these techniques in closure joint design and construction for inland-river immersed tunnels.

The Vibration Response to the High-Pressure Gas Expansion Method: A Case Study of a Hard Rock Tunnel in China

The vibration of rock breaking in tunnel excavation may cause serious damage to nearby buildings if it is not controlled properly. With reference to a hard rock tunnel in China, the vibration response to the high-pressure gas expansion method (HPGEM), an emerging rock-breaking approach, was investigated with field tests, theoretical derivations, and numerical simulations, then comparisons with the traditional dynamite blast were performed. Firstly, the vibration velocity prediction formulas of the two methods were fitted based on the field tests. Subsequently, the accuracy of the formula was verified by numerical simulation, and the vibration attenuation law of the HPGEM was explored. Comparisons were made between the blast and HPGEM, particularly the differences in peak particle velocity (PPV) for different agent qualities, distance from the blasting center, and engineering conditions. Furthermore, this study also analyzed the relationship between the agent qualities and the rock-breaking volume under different cases, finding that the HPGEM has slight vibration and good rock-breaking effect. The HPGEM is thus fully capable of replacing dynamite blasting to carry out rock-breaking operations in certain special areas.

Is online interactive media monitoring effective? Evidence from corporate tunneling in China

We examined the impact of the volume of Q&As from minority shareholders on interactive questions and answers (IQA) platforms in restraining tunneling. The findings suggest that Q&A volumes contribute to less tunneling. We find that by lowering information asymmetry and enhancing firms' internal control effectiveness, IQA platforms play a monitoring function, effectively restraining tunneling. The moderating analysis reveals that the impact of IQA platforms on restraining tunneling is more salient when a firm has (1) only small shareholdings from other large blockholders, (2) low-quality auditors, (3) low institutional investor shareholdings, (4) a large wedge of ownership and control, or (5) controlling shareholders who pledge their shares to financial institutions. Additional analysis suggests that the effectiveness of IQA platforms improves with more timely, thorough, readable, and related replies. Our results support the public policy of providing online platforms for minority shareholders to exercise their rights.

A Study on Deformation Characteristics and Stability of Soft Surrounding Rock for a Shallow-Buried Tunnel

The Heimaguan Tunnel in China serves as a case study to exemplify the variation laws related to surface settlement, deformation, and stress characteristics in a shallow-buried soft-rock tunnel, while emphasizing in the tunnel support requirements. The first stage of this study begins with monitoring the time-varying characteristics of surface settlement, vault subsidence, and the horizontal convergence of Grade V rock. In the second stage, Peck theory is used to calculate the distribution characteristics of surface settlement. The results of both stages are compared to create a vault settlement model, thus establishing the horizontal convergence based on exponential function, logarithmic function and hyperbolic function, and determining the optimal time of secondary lining construction. On this basis, the time-dependent variation laws and characteristics of vertical and horizontal displacement and principal stress of surrounding rock are studied. After this, using simulation and analysis, the proper support is recommended. The study reveals that the surface settlement, vault subsidence, and horizontal convergence of the shallow-buried soft-rock tunnel stabilize within 25–30 days. Peck theory closely aligns with predictions based on exponential functions, with only a 0.72% difference. The recommended time for secondary lining application is 26–27 days.

Life cycle assessment of carbon emissions for cross-sea tunnel: A case study of Shenzhen-Zhongshan Bridge and Tunnel in China

Due to significant population concentration and capital influx in Guangdong-Hong Kong-Macao Greater Bay Area, the construction of cross-sea tunnels with significant consumption of various resources and materials, has been frequently witnessed. However, there is a lack of knowledge regarding how carbon emissions of cross-sea transportation infrastructure are generated across its life-cycle stages. This study proposes a life cycle assessment (LCA) approach for quantifying the carbon emissions and exploring the carbon reduction potentials with a case study of a world-renowned cross-sea tunnel project in Guangdong-Hong Kong-Macao Greater Bay Area. The results find that this project contributes approximately 849 kilotons CO2eq of carbon emissions with an emission intensity of 1.1 kilotons CO2eq per meter. The materialization stage is the largest contributor of carbon emissions (474.9 kilotons CO2eq), followed by service stage (248.3 kilotons CO2eq, accounting for 29.2 %). Some carbon emissions of raw materials can be offset by using recycled materials. The discarded concrete, block, stone, and sand, occupying over 90 % of the total recycled waste in weight could achieve a 93.5 % of carbon reduction potentially. It provides the opportunity to reveal the engineering details and carbon emission for a world-class super complex cross-sea transportation infrastructure. This study makes one of the first attempts to quantify life-cycle carbon emissions of cross-sea transportation infrastructure, which enriches foundational dataset for environmental impact assessment in this emerging field. The findings of this study can provide scientific references for formulating targeted low-carbon strategies for cross-sea transportation infrastructure across its different life-cycle stages.

Evaluation method for health state of highway tunnel structure based on adaptive comprehensive weighting

Accurately evaluating the health state of tunnel structure is of great significance for ensuring the operation safety of tunnel. Based on engineering investigation, fuzzy mathematics and statistical analysis, this paper proposes a new method to evaluate the health state of highway tunnel structure, which considers the multi-disease characteristics and adaptive comprehensive weighting theory. Firstly, by investigating the health state of 20 operation highway tunnels in China, a tunnel disease database with 539 samples was constructed. Considering some new tunnel diseases such as floor heave and lining spalling, a health evaluation index system of highway tunnel was established further. Secondly, utilizing the subjective-objective weighting theory and the principle of variable weight, a new adaptive comprehensive weighting method was proposed to calculate the indexes’ weights. This method overcomes the defect that the constant weight cannot be dynamically updated according to the actual situation of disease development. Then, according to the established four-level classification standard suitable for health evaluation of highway tunnels, the normal distribution membership functions of second-level indexes were determined. Combining with the fuzzy theory, the quantitative evaluation model of tunnel health state was constructed further, which was applied to a case study of the Nanyangshan Tunnel of Kanglin Expressway in China. Furthermore, a comparative analysis with the traditional subjective-objective combination weighting method was conducted, demonstrating the advantages of the proposed evaluation method in terms of engineering applicability and result accuracy. The research findings can provide a decision-making basis for the health maintenance and scientific management of highway tunnels in China.

Analysis and Enlightenment on the Relationships between Two Kinds of Cutter Life Evaluation Indexes and Installation Radius: A Case Study

Accurate evaluation of cutter life at different cutter positions on the cutter head is helpful to determine the time of cutter change and reduce the time of cutter wear measurement, which is of great significance to improve the tunneling efficiency of tunnel boring machine (TBM) projects. Unfortunately, there is no unified cutter life evaluation index now. The field data of cutter wear are collected from a section of a long TBM tunneling water conveyance tunnel in China. Two kinds of cutter life evaluation indexes (based on the radial wear extent of cutter rings and replacement number of cutter rings) are selected and the variation rule between these two kinds of indexes with cutter installation radius is statistically analyzed. The results show that the regression relationships between the two kinds of cutter life evaluation indexes and installation radius mainly present linear functions and quadratic functions. Those regression relationships are affected by factors such as wear type, installation angle, cutter spacing, influence width, and allowable limit wear extent of cutter rings. Considering the calculation accuracy of the evaluation index, the actual working conditions of the disc cutter, and ignoring the influence of tunnel diameter, it is recommended to preferentially choose the radial wear extent of cutter rings per unit rolling distance as the evaluation index of cutter life. The research results can provide a reference for the selection of cutter life evaluation index, prediction of disc cutter life at different cutter positions, and establishment of cutter life prediction mode.

Harnessing fuzzy logic for building structural health during large diameter tunnelling in urban area

Building structural health is constantly jeopardized by tunnel construction, which thus is in a sustained demand for holistic risk assessment and management approaches. In this study, we propose an enhanced consulting fuzzy model with limited information losses to evaluate the static and dynamic risks of building health deterioration during tunnelling. The model integrates three main strategies including, (i) reducing influence of experts’ bias in the ranking processes; (ii) expanding the space of uncertainties in fuzzy environment, and (iii) controlling risk aversion settings through the prospect theory. The construction of the largest diameter (15.3 m) tunnel in China is adopted as a case study to demonstrate the application of the proposed model in assessing the risk statuses of surrounding buildings. Through the proposed model, the risk index can indicate beneficial or detrimental effects of tunnelling and the degree of risk factors delineates priority actions for risk management. The results enable the development of operational risk abatement procedures to enhance the state of practice of large diameter tunnel construction in complex geological conditions.

Development and consideration of Chinese super-large diameter shield tunnel

Since the establishment of the People’s Republic of China, the country has made significant progress in tunnel construction, transforming from a “weak tunnel nation” to a “strong tunnel nation.” As of 2022, China has undertaken more than 60 projects involving large-diameter shield tunnels. To promote the sustainable and high-quality development of large-diameter shield tunnels in China, this article systematically reviews the development history of large-diameter shield tunnels, summarizes the current projects in the country, and addresses various aspects such as construction technology management, design technology, ecological conservation, safety, and intelligence. The article also provides suggestions for the development of large-diameter shield tunnels in China, with the aim of playing a proactive role in promoting their advancement.

Shaking Table Testing and Numerical Study on Aseismic Measures of Twin-Tube Tunnel Crossing Fault Zone with Extra-Large Section

As transportation networks continue to expand into mountainous regions with high seismic activity, ensuring the seismic safety of tunnels crossing active faults has become increasingly crucial. This study aimed to enhance our understanding of the impact of fault zones on the seismic behavior of tunnels and to provide optimized seismic design recommendations through a comprehensive experimental and numerical investigation. The focus of this research is the Xiangyangshan Highway Tunnel in China, which intersects a significant longitudinal fault. Large-scale shake table tests were performed on 1:100 scale physical models of the tunnel to analyze the seismic responses under various ground motion excitations. Detailed three-dimensional finite difference models were developed in FLAC3D and calibrated based on the shake table results. The tests indicated that strains, earth pressures, and accelerations experience localized amplification within 10–20 m of the fault interface compared to undisturbed ground sections. Common seismic mitigation measures, such as rock grouting, seismic joints, and shock absorption layers, were observed to effectively reduce the amplified seismic demands. Grouting, in particular, led to an average reduction of up to 56.3% in circumferential strain and 38.5% in earth pressure. It was concluded that 6 m thick grouted zones and 20 cm thick rubber interlayers between tunnel lining shells provide optimal structural reinforcement against the effects of fault zones. This study provides valuable insights for improving the seismic resilience of underground transportation corridors in seismically active regions.

State‐of‐the‐Art Seismic Studies of Loess Tunnels in China

Large earthquakes occur frequently around the world. Due to the fragility of loess, the effects of seismic events on loess tunnel projects have received considerable in‐depth research attention. In this paper, we systematically review recent seismic research on loess tunnels and highlight deficiencies that require further study with a focus on the following topics: site selection, tunneling through landslides, shallow‐buried tunnels with bias pressure, dynamic analysis, and seismic liquefaction. For tunnels constructed through loess landslides, comprehensive prevention measures should be implemented to ensure the stability of the landslide and tunnel. For shallow‐buried loess tunnels with bias pressure, the lining of the deep‐buried side should receive more attention than that of the shallow‐buried side. It is necessary to consider the combined effects of seismic activity, rainfall, and train load on the stability and fortification of loess tunnels. The stress state of the surrounding loess should also be considered in further studies on tunnel liquefaction. Finally, the laboratory planar strain method should be simplified to address the discrepancy between laboratory and field results.

Prediction of the slurry pressure and inversion of formation characteristics based on a machine learning algorithm during tunnelling in a fault fracture zone

The reasonable setting of the slurry pressure is very important for the safety of shield tunnel construction. In view of the common geological problems of high water pressure and multiple fracture zones in water conveyance tunnels in China, the instability mechanism of the shield excavation face in these formations remains unclear. In this paper, based on the Pearl River Delta Water Resources Allocation Project, various machine learning algorithms are introduced, and the predicted values of the slurry pressure obtained with different machine learning algorithms are evaluated and compared. The optimal machine learning algorithm suitable for this project is determined. Then, using this algorithm, considering the influence of the fault fracture zone, the concept of the formation influence coefficient is proposed, which is used as the input of the prediction model. The influences of the formation coefficient distribution and the influence width of the fracture zone on the accuracy of slurry pressure prediction are examined. Finally, based on this model, the slurry pressure of nearly 100 groups is predicted and verified. The results show that (1) if the influence of the fault fracture zone is considered and a reasonable influence width of the fault fracture zone can be determined, the mean absolute error (MAE) of the predicted slurry pressure is much higher than that of the predictions without considering the fault fracture zone, and the prediction accuracy can be improved by approximately 25%; (2) when the formation influence coefficient is obtained via the method of the theoretical distribution and the influence width of the fault fracture zone is 17 rings, the prediction accuracy of the slurry pressure reaches the optimal value; and (3) through on-site refined investigation, it can be determined that the influence width of the fault fracture zone is 19 rings. The research results of this paper can provide an effective method for setting the shield slurry pressure under high-water pressure conditions in the fault fracture zone.

Assessment of structural performance of super large cross-section subsea RC shield tunnels: Emphasis on the combined effects of highly hydrostatic pressure and corrosion-induced deterioration

For the subsea reinforced concrete (RC) shield tunnels in China, the use of super large tunnel section and the presence of high hydrostatic pressure from seawater have been becoming increasingly common in practical engineering. However, owing to the combined effects of complex structural systems, extreme external loads and aggressive environments, it is a great challenge to sustain a reliable structural performance of these subsea shield tunnels within the prescribed service life. In this study, a novel approach for evaluating the structural safety of a deteriorated large-section subsea RC shield tunnel is presented with an emphasis on the spatial correlation and variation of corrosion damages and the impact of high hydrostatic pressure. Gumbel distributed random fields are established to simulate the spatial variability of steel corrosion in the segmental linings. A random field-based numerical model for the deteriorated RC segmental linings is developed in conjunction with the modeling of nonuniform steel corrosion and local-regional material degradation. In an illustrative example, the effects of the corrosion degree of internal and external steel reinforcements and the level of applied hydrostatic pressure on the structural safety of a large-section subsea RC shield tunnel are investigated.