Bridge Tunnel Research Articles

Effects of canyon wind speed and angle on the aerodynamic performance of a high-speed train passing through canyon tunnel–bridge–tunnel infrastructure

A significant airflow acceleration effect generated by canyon terrain and the bridge poses a serious threat to the safety of train operation in the canyon wind zone. The scale-resolving hybrid turbulence model and overset mesh technology have been employed to investigate the aerodynamic performance of the train traversing a tunnel–bridge–tunnel infrastructure under the canyon wind. Meanwhile, the mechanism of aerodynamic load variation is explored in combination with the characteristics of wind field distribution. The results indicate that the wind speed reaching the windward track of the bridge is about twice the wind speed of far-field inflow. The air within both tunnels will be sucked toward the center of the canyon. The accelerated flow area outside the tunnel portal leads to sudden changes in the lateral force and overturning moment of the train, with the most significant occurring in the head car. The peak of the lateral force and overturning moment coefficients are the highest at wind angles of approximately 60° and 120°, while smaller at 90°, exhibiting an overall approximate “M-shaped” variation pattern. The peak of the sudden change in lift coefficient is later than that of the lateral force coefficient, indicating a lag phenomenon. The direction of vortex shedding is roughly the same as the direction of the composite velocity of train-induced wind and canyon wind, except at the tunnel portal. The research results can provide a reference for the safety of train operation and the design of wind barrier facilities in canyon areas.

Dynamic Response of Bridge–Tunnel Overlapping Structures under High-Speed Railway and Subway Train Loads

With the rapid development of high-speed railroads and subways, there has been an increasing number of bridge–tunnel overlapping structures. To study the dynamic response characteristics of bridge–tunnel structures under the synergistic effects of the vibration generated by high-speed railway and subway trains, the dynamic response characteristics of a bridge–tunnel structure under single-point vibration loading was analyzed by conducting numerical simulations and model tests, with the frequency response function and peak acceleration as the evaluation indices. The dynamic response characteristics of the overlapping structure under moving vibration loads of the high-speed railway and subway trains were further analyzed. The results showed that the dynamic response of the bridge–tunnel overlapping structure increased with the increase in the frequency under the full frequency domain single-point sweep vibration load. The dynamic response of the tunnel hance near the pile foundation side was significantly greater than the vault and invert. Compared with the effect of high-speed train loads alone, the dynamic response of the bridge–tunnel overlapping structure under the synergistic effects of high-speed railways and subways increased significantly and varied at different locations. This investigation provides theoretical support for the design and construction of bridge–tunnel overlapping structures under the synergistic effects of high-speed railways and subways, contributing to improving engineering quality and safety.

Efficient Bayesian model updating for settlement prediction of the immersed tunnel of HZMB

To predict the settlement of the Hong Kong-Zhuhai-Macau Bridge (HZMB) tunnel, a physics-informed machine learning (PIML) algorithm was proposed. This method is effective in predicting total settlement with limited training data. However, its performance is poor when applied to the prediction of joint differential settlement, indicating that the commonly used physical model in the algorithm needs further updating. To ensure the efficiency of model updating, a synthetic case study is employed to demonstrate that prediction performance is inconsequential to the simplification of joint shear stiffness but rather to the insufficient number of foundation moduli in the physical model. Subsequently, five criteria are proposed to guide the model design process and guarantee the efficiency of model class selection. The PIML algorithm and the Bayesian probabilistic approach are then employed to select the most suitable model for predicting settlement. The results of model class selection indicate that the criterion related to tube differential settlement is the optimal choice for the HZMB tunnel, with an optimal number of 57 unknown foundation moduli in the updated model. The analysis with field data proves that the updated model class effectively improves predictions for both total settlement and joint differential settlement.

Settlement prediction of immersed tunnel considering time-dependent foundation modulus

The focus of immersed tunnel research has primarily revolved around settlement monitoring or prediction. However, there has been a lack of discussion regarding the time-dependent effects on settlement prediction, which could lead to obvious misjudgments in subsequent maintenance work. This paper addresses this issue by applying the physics-informed machine learning (PIML) algorithm to conduct an inverse analysis of the foundation modulus of the Hong Kong-Zhuhai-Macau Bridge (HZMB) tunnel, thereby identifying its variation tendency with time. The proposed time-dependent expression of foundation modulus demonstrates that the time-dependent effect is related to both post-construction settlement and the accumulation of back silting, which is significant and could persist throughout the entire service life of the HZMB tunnel. In further studies on settlement prediction for the HZMB tunnel, the results show that errors in prediction can exceed 30 mm at certain monitoring points. This error can be mitigated by considering the time-dependent effect, thereby significantly enhancing the reliability of predictions.

U.S. Hydrodynamic Dredging Challenges and Opportunities

The issue of sedimentation in navigable waterways continually confronts maritime authorities. Regular maintenance dredging, a costly and arduous exercise, is necessary to ensure safe navigation is achievable throughout the year. Private industry and the U.S. Army Corps of Engineers (USACE) combined to remove roughly 230 million cubic yards of maintenance volume at an estimated cost of $1.7 billion in 2020. The handling and disposal of dredged material are practices affected by numerous regulatory constraints. Once a local or national organization has established the most efficient, lowest-cost dredging alternative with the most flexibility, the next step is identifying and addressing permitting concerns and seeking permits to use the technology. Innovative water injection dredging (WID) has been approved in various locations throughout the U.S.A., including providing a reliable means for the North Carolina State Ports Authority (NCSPA) to provide access to its berths, removing sediment over the Chesapeake Bay Bridge–Tunnel to minimize potential harm to the existing tunnel structure, and maintaining federal navigational depth in the Mississippi River. This paper aims to provide a summary overview of the current state of WID in U.S. waterways, including the discussion of a successful permitting and procurement effort by the NCSPA that secured a custom-built WID vessel for North Carolina. Recent literature has identified parameters correlated with WID performance, such as median grain size, hydrology of the waterway, Richardson number, and the liquidity index, which are explored.

Numerical investigation on aerodynamic characteristics of a high-speed train travelling through a bridge–tunnel section under non-uniform airflows caused by mountain terrain effect

A thorough understanding of aerodynamic characteristics of a high-speed train in a bridge–tunnel section is of extremely importance to ensure the vehicle safety of driving. This study presents a numerical investigation on aerodynamic characteristics of a high-speed train travelling through a bridge–tunnel section under non-uniform airflows caused by mountain terrain effect. First, the wind field distribution of the section is obtained from a large-scale numerical simulation model of a mountain terrain. Second, a high-fidelity small-scale model is established to simulate the aerodynamic characteristics. It is validated by the wind tunnel test. Third, the influence of non-uniform wind speeds and wind attack angles airflows on the aerodynamic characteristics are investigated. Finally, a derived empirical equation is introduced to predict the aerodynamic coefficients of the vehicle under non-uniform airflows caused by the mountain terrain. The results demonstrate that due to the effect of mountain terrain, the trend of aerodynamic coefficients varies slowly when the vehicle travels in the bridge–tunnel section. Meanwhile, when the vehicle travels near the tunnel exit, the jumping property of the pressure along the vehicle longitudinal axis is reduced. Furthermore, the predictions of the overturning moment coefficients via the simple empirical equation are consistent with the numerical simulation results.

Long-term environmental impact of an artificial island of solidified dredged marine silt

Marine dredging silt that has been solidified is commonly used as a filler material for inland reclamation and artificial island construction. However, determining the long-term environmental safety of artificial islands made of solidified silt is a challenge. A bridge–tunnel conversion artificial island made of solidified silt was the research location of this study. Laboratory tests were conducted to study the effect of cement content on the pollutant pore-water concentration and hydraulic conductivity of solidified silt. The results showed that after solidification treatment, the heavy-metal concentration in the pore water of dredged silt reduced by 60–85%, whereas the concentration of hydroxide (OH−) ions increased 106–1070 times, and the hydraulic conductivity decreased by approximately three orders of magnitude. On the basis of the test results, the finite-element method was used for simulating the long-term transport of heavy metal nickel (II) (Ni2+) and hydroxide in artificial islands. When the cement content increased from 60 to 100 kg/m3, the nickel (II) concentration in the dam around the solidified silt decreased by approximately 68%, whereas the hydroxide concentration increased approximately tenfold. However, none of them exceeded the seawater water quality standard. This indicates that the long-term environmental safety of the artificial island could be ensured.

Seismic response and damage mechanism of tunnel lining in sensitive environment of soft rock stratum

Abstract In order to investigate the dynamic response characteristics and damage mechanism of the tunnel lining at the tunnel portal in the bridge–tunnel overlapping section in soft rock strata, a physical model with the scale ratio of 1:50 was made based on the similarity theory for shaking table tests. The acceleration and strain results of the tunnel lining under EL Centro seismic waves with different acceleration peak values were studied. Test results show that most of the acceleration values have significant amplification effects compared to input seismic waves, which increased significantly with greater peak values and elevations. Tensile deformations appear along the longitudinal and the circumferential directions of the tunnel lining. The tunnel spandrel and tunnel vault are the maximum deformation parts, respectively, at the standard section and the enlarged section of the tunnel lining. Therefore, it is suggested that the longitudinal anti-tensile design of the tunnel lining at the tunnel portal in such sensitive environments should be strengthened. And the anti-seismic design standard and durability requirement of the standard section of the tunnel lining adjacent to the enlarged section should be improved, so as to meet the requirements for stress deformation and overall stability when subjected to severe earthquakes.

Comparison of aerodynamic performance of moving train model at bridge–tunnel section in wind tunnel with or without tunnel portal

The moving train model test for wind tunnels is an advanced and effective research method for studying the aerodynamic effect of trains passing through tunnel portals in crosswind environments. However, the modelling of tunnel portal structures is cumbersome, and its influence on test results remains unclear. Here, the influence law of the presence and absence of a tunnel portal on the aerodynamic performance of a train was investigated via a wind tunnel test and an improved delayed eddy simulation turbulence model with “mosaic” mesh technology. First, the difference between train locomotion on the windward and leeward side lines with and without a portal was compared from the perspectives of aerodynamic load amplitude, power spectral density (PSD), and standard deviation. Second, the influence of vehicle speed on the amplitude of the train’s aerodynamic load was studied, and the recommended critical speed was determined. Finally, the applicability of the moving model test results under different scale ratios (Reynolds numbers) was explored. Key results show that the aerodynamic load amplitude, PSD peak and standard deviation of the train on the leeward side line are generally higher than those on the windward side line. As indicated by the lift force in the ‘EX’ process without the tunnel portal, the amplitude on the leeward side line is 1.73 time the corresponding values on the windward side line. At speeds of 6, 12 and 18 m/s, when the moving train model speed reaches 12 m/s, the influence of the tunnel portal on the aerodynamic load amplitude can be ignored. The results imply a serious distortion of the aerodynamic load amplitude for the 1:20 model scale, whereas it appears to be appropriate at the 1:16.8 and 1:10 scales. The model test with a Reynolds number of 2.67 × 105 offers an ideal reference value for real trains.

Study on the Application of Grouting Method in Bridge Tunnel Construction Technology

Study on the Application of Grouting Method in Bridge Tunnel Construction Technology

Discussion on the Countermeasures of Soft Soil Foundation Treatment of Highway Bridge Tunnel

Discussion on the Countermeasures of Soft Soil Foundation Treatment of Highway Bridge Tunnel

Field test and numerical reconstitution of natural winds at the tunnel entrance section of high-speed railway

PurposeThe purpose of this paper is to understand the natural wind field characteristics of the tunnel entrance section and analyzing the aerodynamic performance of high-speed railway trains (HSRTs) under natural winds.Design/methodology/approachThree typical tunnel entrance section sites, namely, tunnel–bridge in a dry canyon (TBDC), tunnel–bridge in a river canyon (TBRC) and tunnel–flat ground (TF), are selected to conduct a continuous wind field measurement. Based on the measured wind characteristics, the natural winds of the TBDC and TF sites are reconstituted and imported into the two corresponding full-scale computational fluid dynamics models. The aerodynamic loads of the HSRT running on TBDC and TF with reconstituted winds are simply analyzed.FindingsThe von Kármán spectrum can be used to describe the wind field at the tunnel entrance section. In the reconstituted natural wind condition, a time-varying feature of wind speed distribution and leeward side vortex around the HSRT caused by the wind speed fluctuation is found. The fluctuating amplitude of aerodynamic loads at the TBDC infrastructure is up to 97.9% larger than that at the TF infrastructure.Originality/valueThe natural wind characteristics at tunnel entrance sections on the high-speed railway are first measured and analyzed. A numerical reconstitution scheme considering the temporal and spatial variation of natural wind speed is proposed and verified based on field measurement results. The aerodynamic performance of an HSRT under reconstituted natural winds is first investigated.

Comparison of aerodynamic performance of high-speed train driving on tunnel-bridge section under fluctuating winds based on three turbulence models

The coupled effect of canyon winds and rapid switching of operating scenes deteriorate the aerodynamic performance of the high-speed train (HST) running on the tunnel-bridge section (TBS). What's more, when investigating the aerodynamic performance of the HST by using CFD simulations, the calculation results obtained by various turbulence models show differences, which may have an uncertain effect on analysing the research results. This study aims to analyse the difference in calculation result of three turbulence models, when the HST running on the TBS. For this purpose, based on three mainstream turbulence models (LES, IDDES, and URANS) and the ‘mosaic’ meshing technology, a full-scale CFD dynamic model of 3D train–tunnel–bridge–air was established. Based on the on-site wind field sampling date, UDF program was compiled to load the aforementioned wind-speed time sequence on the velocity-inlet boundary, and the incoming wind field of the TBS was reconstructed. Finally, the aerodynamic load time history and flow field structure of the HST simulated by three turbulence models were revealed, when the HST was running on the TBS. The following conclusions were obtained. The time history of aerodynamic load changes and the fluctuation amplitude calculated by the two turbulence models of IDDES and LES are basically consistent (the difference is kept within 10%), when the HST running on the TBS. The influence of the turbulence model on the aerodynamic loads of the HST is mainly reflected in the head carriage, especially the side force. When the HST runs on the TBS, the side force, lift force, rolling moment, yawing moment and pitching moment of the head carriage calculated by the URANS model are 16%, 9%, 29%, 20%, and 13% higher than the corresponding values of the LES model. Based on the equivalent principle of the side force of the head carriage, a formula is proposed to quantitatively describe the relationship between the side force amplitude of the head carriage on the TBS calculated by the URANS model and the corresponding value of the LES model. The formula can be used to correct the boundary inflow wind speed conditions of the URANS model, so as to quickly obtain the calculation results equivalent to the LES model.

Comparative study on the wind characteristics of tunnel–bridge and tunnel–flat ground infrastructures on high-speed railway

The difference in natural wind characteristics of the tunnel–bridge (TB) and tunnel–flat ground (TF) infrastructure may result in varied aerodynamic behaviours of the high-speed railway train (HSRT). Hence, continuous natural wind sampling is conducted on typical TB and TF sites by using three ultrasonic and one three-cup anemometers. The mean and fluctuating wind characteristics of the two sites are compared and discussed in detail based on field measurement data. The main results can be concluded as follows: Firstly, the prevailing wind direction on the TB site is perpendicular to the running direction of the HSRT due to the occlusion effect, whereas the mean direction on the TF site is easily deflected by the near-ground vegetations and other obstacles. Secondly, the turbulence intensities of the TF site are larger than those of the TB site, and the lognormal distribution is applicable for describing the probability distribution of measured turbulence intensity on the two sites. Thirdly, the von Kármán spectrum accurately depicts the wind energy distribution of the TB and TF sites in the frequency domain, whereas the empirical spectrum adopted by the specification show inferior accuracy. Lastly, the coherence distance of the TB site is considerably longer than that of the TF site. The coherence distance of u and v components of the TB site is seven times longer than a train body (approximately 25 m), and that of u component of the TF site is shorter than two times of a train body.

The Application of Surveying Technology of Independent Control Network in Road and Bridge Tunnel Construction

The Application of Surveying Technology of Independent Control Network in Road and Bridge Tunnel Construction

Discussion on the Construction Technical Management and Quality Control of the Road and Bridge Tunnel Project

Discussion on the Construction Technical Management and Quality Control of the Road and Bridge Tunnel Project

Submerged Floating Tunnel Bridge (SFTB): A Status Report and Evaluation of Technology Readiness Level (TRL)

One of the problems in archipelagic countries is the land transportation system that has not been integrated between islands. In a relatively wide strait and with a high level of depth, it is impossible to build a bridge. In this case, a submerged floating tunnel bridge/SFTB would be an effective choice. SFTB is an underwater tunnel transport route submerged between the seabed and the surface. Known as the "Archimedes Bridge", the basic principle is balancing buoyancy and tension in the mooring cables. Previous studies on SFTB are still in the form of theoretical concepts and ideas. Further research is needed in all relevant sub-topics to actualize the SFTB. This article reviews previous studies, which are grouped into three sub-topics : (1) materials and construction, (2) dynamic analysis, and (3) feasibility/sustainability studies. At the end of this article, a list of research topics that need further study is presented.

Hydrodynamic forces on submerged floating tube: The effect of curvature radius and depth level

The discussion of hydrodynamic forces becomes an important issue in determining the dynamic behaviour of the Submerged Floating Tunnel Bridge (SFTB) structure. As stated in the Morison Equation, the hydrodynamic forces are affected by the kinematics of water particles, but up to this date, there are only a few discussions for curved tube applications. This paper discusses the effect of curvature radius and depth level on hydrodynamic forces to get the correction factor for a straight tube. Tubes with variations in radius curvature (R/L) and diameter (D) were installed in a wave pool with a depth level (z/d). The hydrodynamic forces were detected by a load cell sensor placed on a pedestal at the end of the specimen. The data from the load cell was processed by the data acquisition system and displayed on the monitor screen, showing that the z/d ratio and the R/L ratio both affect the hydrodynamic forces. A larger z/d ratio (deeper) results in smaller hydrodynamic forces, while a smaller R/L ratio (more curved) results in smaller hydrodynamic forces. A correction factor (C) has been determined to calculate the hydrodynamic force on a curved tube based on the Morison equation.

Modelling and simulation of deflection mechanism in rock drilling processing

With the development of social economy, hydraulic drilling machine has been widely used in the tunnel bridge, water conservancy projects and mining. In the process of construction, the drill rod of the hydraulic rock borer in drilling perforating process will produce deviation. It is often caused by the drilling efficiency and reduces the drilling hole scrap, seriously hindered the development of construction technology of drilling and blasting. Through the hydraulic drilling machine drill rod in the drilling cutting process of force analysis, drill rod in horizontal and vertical direction of the mechanical model are established. The relationship between the drill rod force and deflection of drilling in the drilling process is derived. At the same time, build ADAMS mechanical model, and the drilling process is simulated to find the relationship between the depth of drilling and the offset and offset angle. On this basis, the mechanical mechanism of borehole deviation of hydraulic rock drill is clarified, which provides a theoretical basis for the hydraulic rock drill hole deviations.

Analysis of the Application of Waterproof Facilities for the Construction of Road and Bridge Tunnel Projects

Analysis of the Application of Waterproof Facilities for the Construction of Road and Bridge Tunnel Projects