Tunnel System Research Articles

Tunnel squeezing prediction based on partially missing dataset and optimized machine learning models

Accurate prediction of tunnel squeezing, one of the common geological hazards during tunnel construction, is of great significance for ensuring construction safety and reducing economic losses. To achieve precise prediction of tunnel squeezing, this study constructed six reliable machine learning (ML) classification models for this purpose, including Support Vector Machine (SVM), Random Forest (RF), Decision Tree (DT), Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LGBM), and K-Nearest Neighbors (KNN). The parameters of these 6 ML models were optimized using the Whale Optimization Algorithm (WOA) in conjunction with five-fold cross-validation. A total of 305 tunnel squeezing sample data were collected to train and test the models. KNN and Synthetic Minority Over-sampling Technique (SMOTE) methods were employed to handle the missing and imbalanced data sets. An input feature system for tunnel squeezing prediction was established, comprising tunnel burial depth (H), tunnel diameter (D), strength-to-stress ratio (SSR), and support stiffness (K). The XGBoost model optimized with WOA demonstrated the highest prediction accuracy of 0.9681. The SHAP method was utilized to interpret the XGBoost model, indicating that the contribution rank of the input features to tunnel squeezing prediction was SSR > K > D > H, with average SHAP values of 2.93, 1.49, 0.82, and 0.69, respectively. The XGBoost model was applied to predict tunnel squeezing in 10 sections of the Qinghai Huzhu Beishan Tunnel. The prediction results were highly consistent with the actual outcomes.

A new controlled drainage system for submarine tunnels using double-adhesive waterproof membrane

A new controlled drainage system for submarine tunnels using double-adhesive waterproof membrane

Field Monitoring and Analysis of Factors Influencing Existing Tunnels Laterally Adjacent to Foundation Pit Excavations

To investigate the factors influencing existing tunnels adjacent to foundation pit excavations, this paper focuses on a case of excavation of MTR station foundation pits near an existing tunnel. Monitoring data are collected and analyzed, and a two-dimensional numerical model of the pit–tunnel system is established using ABAQUS (2022) software. This study examines the effect of excavation factors on the tunnel, including excavation depth, horizontal spacing between pit and tunnel, support pile wall dimensions, support structure insertion ratio, horizontal support stiffness, and geological conditions. The research results indicate that for tunnels in silty clay formations, the depth of pit excavation should be limited to 20 m. When the horizontal spacing between a foundation pit and tunnel in a silty clay formation is within 1.5 times the depth of excavation, the tunnel is more significantly affected by tunnel excavation works in the adjacent pits. Increasing the horizontal support stiffness has the greatest effect on controlling deformation and stress in the tunnel structure. The degree of influence on deformation and stress in the tunnel due to laterally adjacent excavation of a foundation pit varies with geological conditions. Among them, tunnels in muddy-silty clay and silty soils are the most affected, and it is recommended that reinforcement measures be optimized and monitoring be strengthened. The conclusions of the present study can provide a reference point and guidance for the optimal design of similar pit projects.

Study on the instability of surrounding rock and optimization of support systems in fault-crossing tunnels

Study on the instability of surrounding rock and optimization of support systems in fault-crossing tunnels

Optimization analysis of influencing factors of water mist system in utility tunnel based on orthogonal tests

Optimization analysis of influencing factors of water mist system in utility tunnel based on orthogonal tests

Development of ground integrated debugging system of FL-10 wind tunnel

Development of ground integrated debugging system of FL-10 wind tunnel

Pneumatic tube transport of trastuzumab in IV bags-Effect of headspace and surfactant on subvisible particle formation.

In hospitals, IV bags can be prepared in advance for logistical and microbial safety reasons in a compounding unit and then transported to wards. Transport of protein drugs using a pneumatic tube system has been reported to result in high particle levels. In this study, pneumatic tube transport of trastuzumab in saline polyolefin bags was compared to delivery by hospital porters using an electric platform truck in an underground tunnel system. The transport was tracked using designed smart labels. Two strategies to prevent particle formation, removing headspace and adding the surfactant polysorbate 20 were evaluated. The transport by pneumatic tube had a higher level of shock and vibration than truck delivery. The total particle count measured using flow microscopy also increased more for pneumatic transport than for transport by vehicle. Removing the headspace decreased particle formation for both transports. Surfactant decreases particles over 10 µm for trastuzumab in saline IV bags but increases the total particle levels. Pneumatic tube transport of saline in polyolefin bags resulted in high particle levels and surfactant increased the total particle count. Removing headspace is a measure that can be incorporated into compounding practices to cover for inadequate surfactant levels in IV bags.

Distinct retinal ganglion cell types in strictly subterranean, naturally microphthalmic mammals.

African mole-rats (Bathyergidae, Rodentia) are subterranean rodents that live in extensive dark underground tunnel systems and rarely emerge aboveground. They can discriminate between light and dark but show no overt visually driven behaviours except for light-avoidance responses. Their eyes and central visual system are strongly reduced but not degenerated. Here, we focus on retinal ganglion cells (RGCs). Sighted mammals have numerous RGC types with distinct morphological and functional properties that encode different aspects of a visual scene. We analysed the morphological diversity of 216 intracellularly dye-injected RGCs in the giant mole-rat (Fukomys mechowii) and 48 RGCs in Ansell's mole-rat (Fukomys anselli). Using a hierarchical cluster analysis on 11 morphological parameters, we show that both species possess at least five RGC types with distinct dendritic field sizes and branching patterns. These resemble some RGC types of the mouse and rat, but mole-rat RGCs feature overall sparser and more asymmetric branching patterns. The dendritic trees of most RGCs in all clusters are monostratified in the inner plexiform layer, but bistratified and multistratified/diffuse cells also exist. Thus, although RGC morphologies have become disorganized, the basic retinal organization principle of parallel information processing by distinct RGC types is retained.

Differences for Cooling Capacity of a Cable Tunnel System: Install One or Three Additional Cable Troughs with Cable Circuit for 100/70 Heat Loads – A Numerical Study

The purpose of this report was to compare the numerical analysis for different cooling efficiency of a cable tunnel system when installing one additional cable trough or three cable troughs for cable circuit 100% or 70% heat load. Cable tunnel system is widely known for it is use for high voltage transmission in an underground. Due to the cables generating large quantities of heat, water pipes and air ventilation were used in the tunnel to cool down the transmission cable. To investigate the cooling efficiency of a tunnel, research for benchmark case was carried out. A Computational Fluid Dynamic (CFD) benchmark analysis about 2D natural convection inside the square cavity was investigated to further understand the air movement inside the square medium. Ansys Fluent was carried out for benchmark cases of heat transfer natural convection inside the square cavity and to check whether Ansys Fluent can be used for any CFD and heat transfer purposes by validating the results with previous studies. The benchmark case used a 2D square with different active temperature side walls and adiabatic walls for top and bottom side. From the benchmark simulations with different Rayleigh Number, a number representing buoyancy-driven of a fluid from 103 to 105 affected air differently and the heat transfer natural convection inside the square. At different Rayleigh Number air forms a recirculation passing the active walls and adiabatic walls. After investigated the benchmark, the results were used to validate with previous studies. To validate the results was by using Nusselt Number, ratio of convective to conductive. The benchmark case results were validated and Ansys Fluent proven can be used for CFD and heat transfer purposes. Two 3D cable tunnel were modelled with 100-meter length after concluded the benchmark. The two tunnel models were based on the number of cable troughs installed. The first tunnel was with one cable trough and two cable circuits on the bottom, as for the second tunnel was with one bottom cable circuit and three cable troughs. Cable tunnel simulations were based on cable circuit for 100% heat load and 70% heat load with each heat load case was given different water flow rate of 4.25 L/s and 6.5 L/s. A total of eight scenario cases were carried out to determine which provided a better cooling efficiency choice. The analysis for cable tunnel cases on how the copper cables cooled down through heat transfer of natural convection inside the cable trough, which the heat then was removed from the cable circuit by air and continue to the outside of the tunnel. During the heat transfer processes, conductivity was present as not all heat were removed by air and water, but continue to through the walls of the tunnel and to the ground soil. Based on the simulations, a cable tunnel with three cable troughs was proven more cooling efficiency compared tunnel with one cable trough. Some scenarios did not meet the criteria, due to insufficient heat relocation by air and water. The cooling efficiency was determined by which has the better balance heat relocation by air, water, and ground, also considering the comfort and safety of human inside the tunnel.

Analysis of Factors Affecting the Durability of Electric Power Utility Tunnel Concrete: A Field Investigation

Recently, the service life of electric power utility tunnels has been rapidly increasing; however, inspection and maintenance are difficult because of the characteristics of electric power utility tunnels. In addition, there are no detailed guidelines for electric power utility tunnels regarding the safety and maintenance of existing facilities. Therefore, it is necessary to establish a comprehensive performance evaluation system that reflects the characteristics of electric power utility tunnels. In this study, we determine and evaluate the factors influencing durability for the development of a comprehensive performance evaluation system for electric power utility tunnels via a field investigation.

Agronomic and Post-Harvest Performance of Strawberry Cultivars in High Tunnel and Open-Field Environment in Southeast Virginia

ABSTRACT This study evaluated crop yield potential, season extension, and post-harvest parameters of strawberry cultivars grown in open-field and high tunnel, annual hill production systems. Tested cultivars included “Albion,” “Camino Real,” “Chandler,” “Merced,” “Rocco,” “Ruby June,” “San Andreas,” and “Sweet Ann.” Strawberry plugs were transplanted in the first week of October 2019. The harvest period in the high tunnel was January 2020 through June 2020, while the harvest period in the open-field was April 2020 through June 2020. Except for “Albion” (474 g/plant) having low yield, most cultivars had similar total yields in the high tunnel. “Chandler,” “Rocco” and “Sweet Ann” had the greatest total yields in the open-field (~870 to 780 g/plant). “Albion,” “Merced,” “Ruby June,” “San Andreas” and “Sweet Ann” had the greatest fruit weights in each environment. “Camino Real” and “Ruby June” had the firmest fruit in both environments. In addition, “Merced” produced firm fruits under a high tunnel environment. “Rocco,” and “Ruby June,” had the greatest total soluble solids (~8.7 °Brix) and titratable acidity (>1.85%) in the high tunnel. Total soluble solids for most cultivars were similar in open-field environments. Titratable acidity was greatest (>1.68%) for “Albion,” “Chandler,” “Rocco” and “Ruby June” in open-field production. Different cultivars offered slightly different market-desirable traits. Although the high tunnel system extended the season, achieving marketable yield in high tunnel is challenging due to various biotic and abiotic stresses. Principal component analysis indicated that a more moderate plant size may deliver a greater proportion of large, marketable berries.

COMBINED DECISION SUPPORT MODEL FOR DEVELOPMENT PRIORITIES OF THE KYIV CAR TUNNEL NETWORK

An analysis is conducted for the opportunities to reduce climate (ecological), technogenic and safety risks in the Kyiv transport infrastructure in case of construction of the car tunnel system envisioned in the Kyiv city General plan. The involved structural and functional factors included district type in the potential tunnel’s area, downtown factor, population density, daily pendular movement, arterial network density, aver-age traffic speed at peak hours, surface connectivity of the exits (portals) of the tunnel by automobile roads, surface road throughput, criticalness of the transport infrastructure object, and vulnerability in case of military attacks or terrorist acts. The modified morphological analysis method was applied in the research, that con-sidered groups of climate (ecological) and techogenic risks, and also the military (terrorist) threats. This be-came the basis for construction of the decision support model regarding the evaluation of priorities and rank-ings (rational order) of tunnel construction. Additionally, a combination of morphological analysis with analyt-ical hierarchy process was proposed that provided alternative viewpoints with a different ranking compared to the basic model, depending on the given priorities (weights) of risk factors during decision making. This approach may be useful for development of the transport policy with the goal of approaching climate neutrality for big cities, as well as maximum protection of urban transport infrastructure in conditions of wartime threats.Using the developed system tools and combined models, the urban society can become safer and more resilient, managing transport policies on the basis of the system approach, and multi-criteria analysis of im-pact factors.

Transportation Tunnel Fire Sprinklers and Opportunities

Fire sprinklers are widely accepted as a fundamental building safety feature. Yet, in transportation tunnels where fires grow faster and hotter and exits are farther away, fire sprinklers were prohibited until recently and are still not required in underground rail public assembly areas. Fires in transportation tunnels have resulted in deaths, severe damage to tunnel structures and systems, and costly closures, all of which are preventable with fire sprinklers. The inability to suppress a fire unnecessarily exposes hazardous materials in road tunnels to potentially extreme heat and failing containment, and it sometimes allows hazardous materials to react to heat with extreme consequences. This results in the preventative rerouting of hazardous materials around tunnels at considerable expense to shipping. But we know that fire sprinklers are routinely used to protect hazardous materials manufacturing, processing, storage, and handling outside tunnels. This practice is used in four US road tunnels, which routinely allow unrestricted hazardous materials specifically because of the presence of fire sprinkler systems. Adding fire sprinklers to existing road tunnels could prevent tunnel fires from growing beyond the capability of the undersized ventilation systems which exist in many tunnels. Adding sprinklers could be less expensive than difficult ventilation upgrades. Including sprinklers in new tunnels can limit the fire growth rate and maximum heat release rate and thus reduce the ventilation size as well as passive fire system costs. If life safety is a primary consideration, fire sprinklers should be a cornerstone to improving public safety in transportation tunnels, as they protect occupants from fire as well as allow the safe passage of hazardous materials.

Seismic Response of Ground Penetrating Shield Tunnels Under Lateral Harmonic Excitations: Insights From Shaking Table Test

ABSTRACTThe ground penetrating shield tunnel (GPST) method offers a streamlined approach to tunnel construction in soft ground with limited open‐cut excavation. To explore the seismic response of GPST linings, a series of large‐scale shaking table tests have been conducted, including a variety of seismic excitations. This paper focuses on lateral harmonic excitation. The model tunnel spans a total length of 7.7 m, with the embedment depth ranging from −0.5 to 0.5 times its diameter. The design and fabrication of the model tunnel are presented, including the segmental lining, along with circumferential and longitudinal joints. The soil was modeled with artificial synthetic soil, aiming to simulate the static and dynamic characteristics of the prototype soil. Its composition was adjusted and verified through element tests. The experimental results provide insights into the seismic response of the soil–tunnel system, the ovaling deformation of the segmental lining, as well as the response of the joints between lining segments. The results reveal a strong influence of embedment on tunnel seismic response. The reduction of tunnel embedment leads to a significant increase in lining accelerations and a phase difference, resulting in a “whiplash” effect. In contrast, the ovaling deformation of the lining and the joint apertures decrease with the reduction of embedment. In the sections of the tunnel that are fully embedded, both the acceleration and deformation response of the lining are governed by soil–structure interaction (SSI). A pronounced whiplash effect is observed in the sections of the tunnel that are not fully embedded, due to the absence of soil confinement. The presented experimental results offer valuable insights into the seismic response of GPSTs, which can be of crucial importance for their seismic design.

Study on structural analysis technique of loess tunnel based on multi-index evaluation

Abstract The geological environment of loess tunnel is very complicated in the process of construction and operation, and the actual supporting parameters and surrounding rock pressure of loess tunnel have great uncertainties, which increases the difficulty of performance evaluation. In this paper, a distributed optical fiber monitoring system for loess tunnel is established by means of field investigation, theoretical analysis and field monitoring, which can monitor the tunnel displacement rate, the initial steel arch stress, the axial force of the anchor bolt, the lining stress and the width of the lining crack. Based on the theory of extension, the long-term performance evaluation model of loess tunnel is established, which comprehensively and objectively considers the influence of various influencing factors on the long-term performance of the tunnel, makes a quantitative judgment on the long-term performance of the typical section of loess tunnel, and provides a theoretical basis for the next tunnel maintenance plan, which is of great significance for the improvement of the maintenance technology of loess tunnel.

Excavation method and support systems using empirical design at Pasir Kopo dam diversion tunnel, Lebak, Banten Province, Indonesia

Abstract The design plans for the 433-meter-long Diversion Tunnel in the BBWS Cidanau Ciujung Cidurian area, situated on the right side of the Pasir Kopo Dam in Lebak, Banten, involve the application of the Rock Mass rating (RMR) method for rock mass classification. This approach is also utilized to determine the excavation method for the tunnel, stand-up time, and support systems. In addition, the tunnel support system uses the Q Systems method to address potential geological uncertainties. Surface and subsurface geological mapping, drill core evaluation, and laboratory tests were conducted to collect essential data. Specifically, surface geological mapping and drill core assessment were conducted to evaluate the rock mass quality along the tunnel’s path. Laboratory testing provided details on the physical and mechanical characteristics of the entire rock mass based on drill core samples. The tunnel section consists of a Tuff rock unit and a Lapilli Tuff rock unit, both categorized as having poor (39,83) to fair (42,8 – 48,71) rock mass quality. The drilling and blasting method is recommended, and Excavation techniques differ based on rock mass classification, with the top heading and bench method varying from 1.00m to 1.50m for poor rock (1 zone) and from 1.50m to 3.00m for fair rock (6 zone). The support system for poor rock mass classification includes No steel set required; Rock bolts 3 m and shotcrete 50 mm, and No steel set required, and for fair rock mass, Rock bolts 4 m and shotcrete 50-100 mm in the crown, 30 mm insides. For zones 1,2,5,7 with very poor quality based on Q–Systems support systems using Shotcrete Rock Fibers, Sprayed concrete E = 500 with a 6 cm - 9 cm thickness and bolting length 2.70 m with space 1.5 m – 1.7 m and For zone 3,4,6 using Shotcrete Rock Fibers, Sprayed concrete E = 500 with a 9 cm - 12 cm thickness and bolting length 2.70 m with space 1.3 m – 1.5 m.

Research on the Cutting Control Method of a Shield-Type Cutting Robot

With problems of low cutting efficiency, poor forming quality, and low control accuracy in large-section semi-coal rock roadway tunneling, comprehensive coal tunneling seriously lags behind fully mechanized mining. A fuzzy PID control method was proposed, taking the cutting robot in a shield-type tunneling system as the research object. Using mathematical analysis and other methods, a kinematic model of the cutting robot was established, and the pose transformation matrix of the cutting robot during the cutting process was obtained. A limit model for the motion space of the cutting robot cutting drum was established, and the motion relationship between the driving cylinder and the cutting drum was obtained. A fuzzy PID cutting robot control scheme was designed. The feasibility of the model was validated by simulation methods, and the correctness of the model and simulation was verified through on-site experiments. The results indicate that the established cutting robot model is correct, and the proposed fuzzy PID control method for the cutting robot is feasible. The maximum error of the center control of the cutting drum was 5.5 mm, and the average date was 0.89 mm, which was far less than the standard of 50 mm for engineering of the cross-section cutting of the roadway. This study enriches the control theory of shield-type cutting robots by improving control accuracy, enhancing the cutting efficiency of large-section semi-coal rock tunnels, ensuring the quality of section forming, and narrowing the gap between comprehensive coal tunneling and fully mechanized mining.

Reliability Analysis of High-Pressure Tunnel System Under Multiple Failure Modes Based on Improved Sparrow Search Algorithm–Kriging–Monte Carlo Simulation Method

It is often difficult for a structural safety design method based on deterministic analysis to fully and reasonably reflect the randomness of mechanical parameters, while the traditional reliability analysis method has a large calculation cost and low accuracy. In this paper, based on the seepage–stress coupling numerical model, the random variables affecting the reliability of the collaborative bearing of surrounding rock and lining structures are successfully identified. Then, the improved sparrow search algorithm (ISSA) is used to optimize the hyper-parameters of the Kriging surrogate model, in order to improve the computational efficiency and accuracy of the reliability analysis model. Finally, the ISSA-Kriging-MCS model is used to quantitatively evaluate the reliability of the surrounding rock-reinforced concrete lining structure under multiple failure modes, and the sensitivity of each random variable is discussed in depth. The results show that the high-pressure tunnel structure has high safety and reliability. The reliability indexes of each failure mode decrease with the increase in the coefficient of variation (COV) of random variables. In addition, the same random variable also exhibits varying degrees of influence in different failure modes.

A small-sized fire detection method based on the combination of the SIC algorithm and 1-DCNN

The article proposes a method for detecting small-sized fires using an Ultra-Weak Fiber Bragg Grating (UWFBG) array fire monitoring system, addressing issues of slow response speed and insufficient spatial resolution in traditional fire monitoring systems. The system’s spatial resolution is improved by regional subsection monitoring and using the Spectral Intensity Change (SIC) algorithm combined with a one-dimensional convolutional neural network (1-DCNN) model for hot spot recognition. This approach can ignore the impact of noise on the reflected spectra to some extent, overcoming the limitations of traditional methods. Simulation results demonstrate that when the signal-to-noise ratio (SNR) is above 10 dB, the accuracy of hot spot recognition is significantly improved. At an SNR of 15 dB, the recognition accuracy reaches 98.5 %. Furthermore, addressing the spectral distortion issue in the sensor array, introducing the 1-DCNN model achieves a recognition accuracy of 98.6 %. The proposed method can identify small-sized fires of 10 cm, providing a safe and reliable solution for fire monitoring systems in subway tunnels.

Neighbourhood Sum-Based Structural Analysis for Sodalite System

Background: Sodalite is a type of zeolite with an intricate structure comprising a system of interrelated cages and tunnels. It is extensively used in sieving applications due to its unique structure and properties. As a result, it finds several uses in water and air purifica-tion, radioactive decontamination, detergents, and so on. Due to the potential positive envi-ronmental impact of sodalite materials, analysing the molecule at a structural level becomes the need of the hour. Methods: Molecular descriptors form the basis of many convenient and cost-effective tech-niques for studying molecular structures. In this article, the neighbourhood sum-based de-scriptors are computed edge-partition techniques, simplifying the intricate structures with cages and tunnels into more simple graphs for mathematical convenience. Results: This article presents the calculated analytical expressions for molecular descriptors, specifically focusing on various neighbourhood sum degree-based indices in sodalite struc-tures. Conclusion: The results presented in this article establish the dependence of the physical properties of a molecule on its underlying structure using the computed molecular de-scriptors. The graphical comparison of the results provides a visual representation of the be-haviour of indices with respect to the molecular structure.