Underwater Tunnel Research Articles

Performance-based design of joint waterproofing of segmental tunnel linings using hybrid computational/experimental procedures

Precast segmental linings of underwater tunnels, excavated by tunnel boring machine (TBM), are key components of infrastructure that is inevitably subjected to a relatively high-water table head. Many underwater tunnels experience various degrees of water leakage issues at the tunnel joints. A rigorous joint waterproofing design is indispensable to guarantee the normal operation of tunnels. However, to date, little attention has been devoted to gaining a better understanding of the water leakage behavior of joints and the associated design method. In this paper, a combined experimental- and computational-based design framework for joint waterproofing is presented, in compliance with the most recent guidelines. The proposed step-by-step design procedures incorporate the identification of design parameters and criteria, pre-test finite element (FE) analysis, experimental evaluation, and post-test FE analysis. The gasket assembly ability refers to the shear capacity check of the gasket groove during the construction stage, while the joint waterproof capacity consists of both the short- and long-term waterproof capacities of the joints in the most unfavorable deformation state during the service stage. A pre-test analysis is performed to evaluate the preliminary gasket profiles and is followed by experimental testing of the short-term waterproofing performance of the joint. A post-test FE analysis is performed to check the groove shear capacity and to predict the long-term waterproofing performance of the joint. A design case study of a recently built underwater tunnel in China is presented to illustrate the implementation of the proposed design procedures into practice. Finally, recommendations on the contribution of the governing variables on the waterproofing performance of the joint are provided, outlining crucial aspects that may be considered by engineers in the design of underwater tunnels.

History of the subterranean connections between Calcutta and Howrah

The first metro railway started operation on London’s Metropolitan Railway line using steam locomotives and wooden carriages (1863). Although Calcutta, India, acquired its metro in 1984, its connection with Howrah through an underwater tunnel under the River Hooghly was first conceived in 1921. Plans for this were laid out by Sir Harley Dalrymple-Hay, and he prepared the blueprint of a railway from Calcutta to Howrah with ten stations over its 10·6 km stretch. Unfortunately, the project was abandoned by the government of Bengal on financial grounds. Then, in 1928, Calcutta Electric Supply Corporation, to cater for increasing power demand on both sides of the river, consulted Sir Dalrymple-Hay to provide a tunnel below the lowest scour level of the river. It was planned to provide a conduit for electrical cables with inspection facilities, and this tunnel was built in 1931. Calcutta’s East–West metro line, including the underwater stretch below the River Hooghly, was reconceived in 2006, and construction started in 2009. This line now crosses the River Hooghly with a rail level at a depth of 19 m below the riverbed with 13 m of water depth at average tide, and its projected daily commuters will be almost 1 million by the year 2035.

Underwater noise generated by vehicle traffic in an underwater tunnel

Underwater noise measurements were made adjacent to the Monitor-Merrimac Memorial Bridge-Tunnel in the James River, VA during a field experiment in April of 2019. Anticipated sources of underwater noise included wind, waves and associated bubbles, flow noise, boat/ship traffic, industrial shipyard noise and traffic noise radiating from the underwater tunnel. During the field observations, winds, waves/surface conditions, underwater currents, water column structure and tunnel traffic were monitored by anemometers, high-frequency surface radar, ADCPs, echosounders and traffic sensors. The observed noise field exhibited high frequency and tidal-scale variability due to passing surface vessels and tidally driven currents in the estuary; most interestingly, the noise field exhibited variability on a diurnal time scale, closely correlated to the temporal distribution of vehicular traffic in the underwater tunnel. The tunnel traffic underwater noise amplitude varied by 1–5 dB at 10s to 100s of Hertz and exhibited a non-linear relationship to frequency.

Damage assessment and mitigation measures of underwater tunnel subjected to blast loads

The damage prediction and protective measures of tunnels subjected to blast loads have gained importance in recent years due to increasing accidental events and terrorist attacks. This paper performs numerical modeling to assess the damage characteristics of an underwater tunnel subjected to blast loads and explore the potential mitigation measures. Firstly, a three-dimensional numerical model of an underwater tunnel based on coupled Lagrange and Euler (CLE) method is developed. The accuracy of the CLE method and material models is verified with blast testing data. Subsequently, the dynamic response and damage evolution of the tunnel subjected to underwater explosions are investigated. Potential failure patterns due to various underwater blast loads are explored. Intensive numerical simulations are then carried out to investigate the damage levels of the tunnel. Based on numerical data, empirical relations are suggested to predict the tunnel damage levels based on charge weight and standoff distances. CFRP (carbon fiber reinforced polymer) cloth is used to improve the resistance of the tunnel to underwater explosions. Mitigation effects of different strengthening schemes are investigated, and the optimum strengthening thickness of the CFRP cloth is recommended. The results show that the rigidity and load carrying ability of the tunnel are significantly improved by bonding the CFRP cloth. The recommended thickness of the CFRP cloth is 0.5–0.835 mm.

Seepage Analysis and Optimization of Engineering Method for Municipal Underwater Tunnel Construction in Urban Coastal Stratum

Li X.-Z.; Zhu, Y.-Q., and Zhao, J., 2019. Seepage analysis and optimization of engineering method for municipal underwater tunnel construction in urban coastal stratum. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 260–263. Coconut Creek (Florida), ISSN 0749-0208.A municipal tunnel is a double-deck tunnel shared by traffic and municipal corridors. It is an underwater tunnel in the coastal stratum. Water seepage must be considered during the tunnel construction process. By establishing a three-dimensional geo-mechanical calculation model and considering the seepage, the construction process of the two construction methods, the step method and the CRD method, is analyzed. The CRD method is better in controlling tunnel deformation, tunnel seepage and pore water pressure distribution.

일본 세이칸(青函)터널의 건설과 기술적 함의(含意)에 관한 연구 - 한일터널 건설논의에 대한 시사점 -

This study examines the construction process of the Seikan Tunnel. Through this, I have made suggestions for the future discussion on the construction of the Underwater tunnel between Korea and Japan. The following framework of analysis was used for this purpose: 1) Natural basic conditions of the Tsugaru Strait, 2) Limitations of construction and technology, and 3) Active development of tunnel construction technology. In particular, it was predicted that the construction of the Seikan Tunnel was a difficult construction. The rapid sea currents, deep seas, and the complicated submarine geology of the Tsugaru Strait made the construction very difficulte. Above all, fragile geology and complex geotechnical structures could not be resolved by civil engineering and equipment at that time. Nevertheless, Japan has developed a new tunnel construction technology and completed the Seikan Tunnel. As a result, Japan has established a relatively safe railway infrastructure. In particular, Japan has developed underwater tunnel excavation technology in the process of constructing the Seikan tunnel. As a result, Japan has the world's most advanced tunnel technology. These facts are expected to provide policy implications for discussions on the construction of the Underwater tunnels between Korea and Japan to be developed in the future.

Response spectra of trains to earthquakes

Currently, the construction of railways for high-speed traffic is developing intensively. Overcoming water obstacles is carried out by the construction of artificial structures such as bridges and tunnels. It often becomes necessary to cross areas with increased seismic activity by rail lines. Which, in turn, increases the likelihood of crews on bridges and in tunnels during earthquakes. With adverse combinations of dynamic parameters during earthquakes, fluctuations may occur that threaten the safety of movement. In this regard, it is necessary to evaluate the response of rolling stock to the effects of this kind. Vertical and horizontal oscillations of rolling stock during earthquakes can reach large quantities, which is fraught with serious consequences. Dynamic characteristics of locomotives and cars have significant differences. Locomotives and wagons can be of different brands, in addition, wagons can be empty and loaded. The parameters of earthquakes that can occur in a given area can also be diverse. To solve such a complex task, the authors of the article use the widely used abroad concept of response spectra, which allows to evaluate the response of objects with different natural frequencies to all possible earthquakes. The amplitude Fourier spectra and the spectra of the maximum reactions at speeds have the same dimensions. There is a relationship between these functions, which is used to construct response spectra if the amplitude Fourier spectrum of the ground acceleration function is known. Therefore, to construct the response spectra of the crews for earthquakes, the Fourier amplitude spectra of the base oscillations were used as the initial data. The results presented in the article are part of the dissertation research «Assessment of the dynamic effects of railway and natural origin on underwater tunnels» Pestryakova E.A.

Face Stability Assessment for Underwater Tunneling Across a Fault Zone

AbstractFace stability is critical for the safety of underwater tunnel construction across fault zones. This paper presents a new analytical method that can be used to assess such stability. Follow...

Intelligent control of a large underwater tunnel sinking pipe hoisting manipulator

To improve the intelligence of sinking pipe hoisting in the underwater tunnel, an intelligent mechanical arm is used for hoisting control. This paper presents an intelligent control technique based on loading of load transfer mechanism and state feedback regulation without joint for lifting and hoisting manipulator of large underwater tunnel. This paper analyzes the technical preparation flow and key technology of the lifting of large underwater tunnel pipe sinking, and constructs the constraint parameter model of the pressure control of the pipe sinking pipe hoisting arm of the large underwater tunnel. The load-transfer mechanism of large underwater tunnel sinking pipe hoisting manipulator is analyzed, and the moving platform and power driving unit of hoisting arm are established. Combined with the compensation method of end position and attitude parameters of multi-joint tracking, the pressure bearing mechanical control of large underwater tunnel sinking pipe hoisting mechanical arm is carried out, and the control law of large underwater tunnel sinking pipe hoisting robot arm is constructed by using finite element dynamic analysis method. The pressure torque control of large underwater tunnel pipe hoisting mechanism arm is realized, and the position and pose adjustment ability of large underwater tunnel sinking pipe hoisting is improved, and the docking error of sinking pipe hoisting is reduced. The simulation results show that this method has good stability for intelligent control of large underwater tunnel sinking pipe hoisting robot arm, and the accuracy of position and pose tracking for large underwater tunnel sinking pipe hoisting process is high. The safety and intelligence of sinking pipe hoisting in the underwater tunnel are improved.

Impacts of confining pressure and safety thickness on water and mud inrush in weathered granite

Due to the strong disintegration and water erosion of completely weathered granite, water and mud inrush disasters are apt to take place in this zone during underwater tunnel construction. The pore, compactness, seepage path length, fracture geometries and their interconnections for water and mud transfer are strongly influenced by confining pressure and waterproof-resistant slab safety thickness. In order to inspect the influence, a series of experiments based on a self-designed testing system and non-Darcy testing method were performed. The results indicated that the water and mud inrush evolution increased with the increase of confining pressure and decreased with the increase of safety thickness. In particular, the confining pressure mainly influences the initial evolution stage, and a critical safety thickness to prevent water and mud inrush is obtained. Besides, the non-Darcy testing method results shows that the water and mud inrush evolution affects the influence of non-Darcy flow. For example, while the safety thickness was smaller than the critical value, the evolution was large and unstable and its behavior transferred into nonlinear. In this case, the flow changed to non-Darcy flow.

Development and Application of Fire Video Image Detection Technology in China’s Road Tunnels

A large number of highway tunnels, urban road tunnels and underwater tunnels have been constructed throughout China over the last two decades. With the rapid increase in vehicle traffic, the number of fire incidents in road tunnels have also substantially increased. This paper aims to review the development and application of fire video image detection (VID) technology and their impact on fire safety in China’s road tunnels. The challenges of fire safety in China’s road tunnels are analyzed. The capabilities and limitations of fire detection technologies currently used in China’s road tunnels are discussed. The research and development of fire VID technology in road tunnels, including various detection algorithms, evolution of VID systems and evaluation of their performances in various tunnel tests are reviewed. Some cases involving VID applications in China’s road tunnels are reported. The studies show that the fire VID systems have unique features in providing fire protection and their detection capability and reliability have been enhanced over the decades with the advance in detection algorithms, hardware and integration with other tunnel systems. They have become an important safety system in China’s road 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.

РАСЧЕТ МНОГОСЛОЙНЫХ ОБДЕЛОК КОМПЛЕКСОВ ПАРАЛЛЕЛЬНЫХ ПОДВОДНЫХ ТОННЕЛЕЙ С УЧЕТОМ ПОСЛЕДОВАТЕЛЬНОСТИ СООРУЖЕНИЯ

The analytical design methodfor multilayer non-circular linings of complexes mutually influencing underwater tunnels with the sequence of their driving is proposed. The method is based on the solution of the corresponding elasticity theory plane problem based on the application of the analytical functions of complex variable apparatus, conform mapping and properties of Cauchy-type integrals. The method is implemented in the form of a complete calculation algorithm and the original computer program. Specific results of design illustrating the effect of the sequence of construction of a complex consisting of three underwater tunnels on the stress state and load - bearing capacity of multilayer underground structures are presented.

Water Transport in Unsaturated Cracked Concrete under Pressure

In order to analyze the process of hydraulic water infiltrating cracked concrete of underwater tunnels, the equation of water transport in unsaturated cracked concrete under pressure was proposed according to the double‐porosity medium model. Penetration tests on prefabricated cracked concrete blocks were conducted, and then the influence of hydraulic pressure, initial saturation, and crack width on water transport was studied. The results show that the larger the water pressure, the lower the initial saturation, and the wider the crack width, then the greater the penetration depth, which can be reasonably explained according to water motion theoretical models in this study. Moreover, the TOUGH2 software was used to simulate the change and distribution of saturation, driving potential, and water velocity of unsaturated cracked concrete, which further proved the experimental results and theoretical analysis. It reflects that both pressure potential and matric potential are the driving force of water transport in underwater cracked concrete, and the driving force will be converted with the change of concrete saturation. In addition, crack width is positively correlated with concrete permeability.

Analytical analysis of working face passive stability during shield tunneling in frictional soils

This paper develops the 2D and 3D kinematically admissible mechanisms for analyzing the passive face stability during shield tunneling using upper-bound analysis. The mechanisms consider trapezoidal distribution of support pressure along tunnel face and partial failure originated at tunnel face above invert. For cohesionless soils, the support pressure is a function of soil effective frictional angle φ′ which determines the inclination of failure block and the normalized soil cover depth C/D (soil cover depth/tunnel diameter) which affects the origination of the passive failure. For cohesive soils, the support pressure is a function of φ′, C/D, and the effective cohesion c′. The cohesion c′ has a relatively smaller impact on the support pressure than φ′ and C/D have. The mechanisms are verified by comparing the current solutions with a previous upper-bound solution. The comparison shows that the current solutions are a general solution which is capable of predicting the passive face failure originated at any depth along tunnel face and the previous solution is a particular solution with the assumption that the face failure originated at tunnel invert. The mechanisms are validated through application to a practical project of shallowly buried, large diameter underwater tunnel. The validation shows that the mechanisms are capable of assessing the tunnel face passive instability rationally.

An Analytical Model of Seepage Field for Symmetrical Underwater Tunnels

Based on the mirror image method and superposition principle, an analytical model of seepage field for symmetrical underwater tunnels is proposed. The condition is assumed as two-dimensional steady water inflow into symmetrical and horizontal underwater tunnels in a fully saturated, homogeneous, isotropic, and semi-infinite aquifer. Analytical solutions of pore water distribution and water inflow into tunnels are obtained. Two different boundary conditions at the perimeter of symmetrical tunnels are considered, constant total hydraulic head and constant water pressure. Taking the subsea tunnels of Xiamen Xiang’an in China as an example, comparisons between analytical solutions and numerical solutions are analyzed in the case of zero water pressure at the perimeter of symmetrical tunnels. The results show that the analytical solutions for pore pressure distribution and water inflow match well with the numerical solutions and that the relative deviations are all in an acceptable range. The solutions derived from the analytical model in this paper can analyze the steady seepage field of symmetrical underwater tunnels accurately and reasonably.

Numerical simulation of slurry fracturing during shield tunnelling

The slurry type shield method is an important tunnelling method, especially for underwater tunnels in soft soil. If the slurry pressure is too high, it may lead to slurry fracturing of the stratum in front of the excavation face and cause water inrush accidents. Controlling the face stability of shallow shield tunnels is difficult owing to the inadequate understanding of the slurry induced fracturing mechanism. Most importantly, understanding the details of the slurry fracturing propagation process is not enough, as the process is especially complicated. However, the propagation process cannot be directly observed in the field or in small-scale laboratory tests because it occurs in bodies of soil. Thus far, an effective approach to investigate the slurry fracturing mechanism in the surrounding stratum of a slurry shield tunnel has not been reported. In this paper, a numerical simulation method for evaluating tunnelling-induced slurry fracturing is presented. The developed numerical model considered the couplings of stress distribution, fluid flows, and fracturing. The fracture initiation, branching, and propagation in the stratum could be reproduced numerically. A series of simulations for different ratios of cover depth to tunnel diameter were carried out to investigate the propagation process of slurry fracturing. The effects of slurry pressure at the tunnelling face and the cover depth above the tunnel were investigated. The results of the fracturing process induced by slurry, such as the fracture propagation velocity, slurry pressure distribution along the fracture, fracture initiation pressure, fracture extending pressure, and stratum deformations, were analyzed.

Recent progress and application on seismic isolation energy dissipation and control for structures in China

China is a country where 100% of the territory is located in a seismic zone. Most of the strong earthquakes are over prediction. Most fatalities are caused by structural collapse. Earthquakes not only cause severe damage to structures, but can also damage non-structural elements on and inside of facilities. This can halt city life, and disrupt hospitals, airports, bridges, power plants, and other infrastructure. Designers need to use new techniques to protect structures and facilities inside. Isolation, energy dissipation and, control systems are more and more widely used in recent years in China. Currently, there are nearly 6,500 structures with isolation and about 3,000 structures with passive energy dissipation or hybrid control in China. The mitigation techniques are applied to structures like residential buildings, large or complex structures, bridges, underwater tunnels, historical or cultural relic sites, and industrial facilities, and are used for retrofitting of existed structures. This paper introduces design rules and some new and innovative devices for seismic isolation, energy dissipation and hybrid control for civil and industrial structures. This paper also discusses the development trends for seismic resistance, seismic isolation, passive and active control techniques for the future in China and in the world.

An improved radius-incremental-approach of stress and displacement for strain-softening surrounding rock considering hydraulic-mechanical coupling

This study focused on the mechanical and hydraulic characteristics of underwater tunnels based on Mohr-Coulomb (M-C), Hoek-Brown (H-B) and generalized H-B failure criteria. An improved approach for calculating stress, displacement and plastic radius of the circular tunnel considering hydraulic-mechanical coupling was developed. The innovation of this study was that the radius-incremental-approach was reconstructed (i.e., the whole plastic zone is divided into a finite number of concentric annuli by radius), stress and displacement of each annulus were determined in terms of numerical method and Terzaghi\'s effective stress principle. The validation of the proposed approach was conducted by comparing with the results in Brown and Bray (1982) and Park and Kim (2006). In addition, the Rp-pin curve (plastic radius-internal supporting pressure curve) was obtained using the numerical iterative method, and the plastic radius of the deep-buried tunnel could be obtained by interpolation method in terms of the known value of internal supporting pressure pin. Combining with the theories in Carranza and Fairhurst (2000), the improved technique for assessing the reliability of the tunnel support was proposed.

Typical Underwater Tunnels in the Mainland of China and Related Tunneling Technologies

Abstract In the past decades, many underwater tunnels have been constructed in the mainland of China, and great progress has been made in related tunneling technologies. This paper presents the history and state of the art of underwater tunnels in the mainland of China in terms of shield-bored tunnels, drill-and-blast tunnels, and immersed tunnels. Typical underwater tunnels of these types in the mainland of China are described, along with innovative technologies regarding comprehensive geological prediction, grouting-based consolidation, the design and construction of large cross-sectional tunnels with shallow cover in weak strata, cutting tool replacement under limited drainage and reduced pressure conditions, the detection and treatment of boulders, the construction of underwater tunnels in areas with high seismic intensity, and the treatment of serious sedimentation in a foundation channel of immersed tunnels. Some suggestions are made regarding the three potential great strait-crossing tunnels—the Qiongzhou Strait-Crossing Tunnel, Bohai Strait-Crossing Tunnel, and Taiwan Strait-Crossing Tunnel—and issues related to these great strait-crossing tunnels that need further study are proposed.