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Advances in Tunnel and Underground Construction
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Advances in Tunnel and Underground Construction

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: 20 August 2024 | Viewed by 30358

Special Issue Editors

Prof. Dr. Zhongsheng Tan

E-Mail Website
Guest Editor
School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Interests: mountain tunnel; underwater tunnel; urban tunnel; TBM tunnel; foundation pit engineering
Prof. Dr. Xiuying Wang

E-Mail Website
Guest Editor
School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Interests: mountain tunnel; underwater tunnel; urban tunnel

Special Issue Information

Dear Colleagues,

We are inviting submissions to a Special Issue titled “Advances in Tunnel and Underground Construction”.

Tunnels are inseparable from human life. Successful tunnel construction can facilitate people's lives. At present, the construction of some tunnels still faces significant challenges, such as squeezing tunnels and high-temperature tunnels. Tunnel construction technology requires significant changes. Therefore, it is necessary to carry out research on tunnel construction technology in order to improve the level of tunnel construction in the world.

The purpose of this Special Issue is to collect excellent papers on tunnel construction, including, but not limited to, topics such as tunnel construction technology and construction mechanical behavior. Relevant review papers are also welcome.

Prof. Dr. Zhongsheng Tan
Prof. Dr. Xiuying Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • tunnel construction technology
  • tunnel construction management
  • construction mechanical behavior
  • construction mechanical response

Published Papers (27 papers)

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18 pages, 14730 KiB  
Article
Stability of a Deep Foundation Pit with Hard Surrounding Rocks under Different in-Time Transverse Supporting Conditions
by Yang Li, Zhanguo Ma, Furong Gao, Peng Gong, Zhiqun Gong and Kelong Li
Appl. Sci. 2024, 14(7), 2914; https://doi.org/10.3390/app14072914 - 29 Mar 2024
Viewed by 344
Abstract
This paper focuses on investigating the stability of a deep foundation pit with hard surrounding rocks at different excavation stages with different supporting schemes by means of numerical calculations. The supporting schemes in question were combinations of one fixed vertical support and four [...] Read more.
This paper focuses on investigating the stability of a deep foundation pit with hard surrounding rocks at different excavation stages with different supporting schemes by means of numerical calculations. The supporting schemes in question were combinations of one fixed vertical support and four varied transverse supports. Drilled grouting piles were used as vertical supports, and the commonly used steel bracings and prestressed anchorages served as transverse supports. The parameters used to evaluate the stability of the foundation pit at different excavation stages included the lateral displacements of the surrounding rocks, the settlement of the surrounding ground, the axial forces of steel bracings, and displacements at the tops of the drilled grouting piles. Simulation results showed that when a transverse supporting scheme consisting of one-layer steel bracings and prestressed anchorages set at 9 m and 22.5 m underground, respectively, was adopted, the lateral displacements of the surrounding rocks and settlement of the surrounding ground at different excavation stages were the largest compared to those under the other three transverse supporting schemes, while the corresponding values were lower compared to those allowed in Chinese standard GB50007-2011, demonstrating that this kind of supporting scheme is effective in terms of ensuring the safety of the foundation pit at different excavation stages. Moreover, the setting techniques for this kind of supporting scheme were relatively simple, and the corresponding influences of supporting element arrangements on excavation techniques were the lowest. Therefore, one-layer steel bracings and one-layer prestressed anchorages constituted the most suitable transverse supporting scheme for excavating a deep foundation pit with hard surrounding rocks. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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18 pages, 3170 KiB  
Article
Optimization of Tunnel Construction Schedule Considering Soft Logic
by Jianying Wei, Yuming Liu, Xiaochun Lu, Yu Feng and Yadi Wang
Appl. Sci. 2024, 14(6), 2580; https://doi.org/10.3390/app14062580 - 19 Mar 2024
Viewed by 395
Abstract
Tunnel construction projects are a classic type of repetitive project, and hold a crucial position in the construction industry. The linear scheduling method (LSM) has been in the spotlight in scheduling optimization for repetitive construction projects since it was first proposed. However, the [...] Read more.
Tunnel construction projects are a classic type of repetitive project, and hold a crucial position in the construction industry. The linear scheduling method (LSM) has been in the spotlight in scheduling optimization for repetitive construction projects since it was first proposed. However, the possibility of changing the construction sequence during application is very often overlooked, which is not in line with actual engineering practices. Incorporating soft logic into LSM and considering the characteristics of tunnel construction, we propose an optimization method for the tunnel construction schedule to shorten the duration by opening up an additional working surface. A mixed-integer programming (MIP) model is developed, which considers various constraints, such as construction sequence and work continuity. The exact algorithm and genetic algorithm (GA) are designed via Python, and the validity is verified through practical cases. A comparative analysis was conducted between the two algorithms and their outcomes demonstrates that the method can satisfy the restrictive constraints of tunnel construction projects. In addition, improvement strategies for tunnel construction management are recommended. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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21 pages, 5304 KiB  
Article
An Experimental Study on the Sealing Mechanism of a Karst Pipeline by Dynamic Water Grouting
by Jie Liu, Shuai Liu, Mingyuan Wang and Bo Peng
Appl. Sci. 2024, 14(4), 1381; https://doi.org/10.3390/app14041381 - 08 Feb 2024
Viewed by 467
Abstract
Aiming at the problem of water burst plugging in karst pipelines, in this paper, a new type of waterborne epoxy resin magnetic self-polymerization grouting material (WEMS) suitable for karst pipeline water burst plugging was developed, and a visual simulation test device for karst [...] Read more.
Aiming at the problem of water burst plugging in karst pipelines, in this paper, a new type of waterborne epoxy resin magnetic self-polymerization grouting material (WEMS) suitable for karst pipeline water burst plugging was developed, and a visual simulation test device for karst pipeline water burst grouting plugging was designed and built. Through the orthogonal test of grouting plugging, the influence of different factors on the effect of grouting plugging was analyzed, and the shear mechanism of magnetic slurry magnetization plugging was also analyzed. The results showed that (i) the best grouting sealing performance was achieved when the new WEMS had a water–cement ratio of 0.35–0.55 and Fe3O4 powder misery of 20–40%. (ii) The primary relationship between the factors affecting the dynamic water flow rate and slurry retention is Fe3O4 power ratio > plugging length > water–cement ratio. (iii) The relationship equation was established between the shear strength of magnetic self-polymerizing slurry and the magnetic field strength, blocking length, and slurry ratio. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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16 pages, 6883 KiB  
Article
Complex Function Solution of Stratum Displacements and Stresses in Shallow Rectangular Pipe Jacking Excavation Considering the Convergence Boundary
by Yaze Wang and Yanyong Xiang
Appl. Sci. 2024, 14(3), 1154; https://doi.org/10.3390/app14031154 - 30 Jan 2024
Cited by 1 | Viewed by 485
Abstract
The construction of pipe jacking has little impact on the environment and is usually used to build underground passages with shallow buried depths and short lengths. Compared with circular pipe jacking, rectangular pipe jacking has the advantages of shallow buried depth and high [...] Read more.
The construction of pipe jacking has little impact on the environment and is usually used to build underground passages with shallow buried depths and short lengths. Compared with circular pipe jacking, rectangular pipe jacking has the advantages of shallow buried depth and high space utilization. Therefore, research on the excavation of rectangular pipe jacking is necessary. This paper establishes a cross-section model of shallow buried rectangular pipe jacking excavation. Taking advantage of complex functions for solving problems involving non-circular tunnels, an analytical solution is obtained using an approximate mapping function and potential functions in series forms for the stress and displacement of the stratum with a displacement condition at the excavation boundary and a stress condition at the ground surface boundary. The finite element simulation results and the engineering-measured data are used for comparisons and verifications. With the analytical solution of the complex function, the influence of selecting control points for the mapping function on the accuracy is calculated and analyzed, as well as the influence of the stratum loss rate, span, buried depth, and stratum unit weight on surface subsidence and major principal stress of the excavation boundary. The proposed analytical solution can be applied to the construction of rectangular pipe jacking tunnels. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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16 pages, 3432 KiB  
Article
Hazard Prediction of Water Inrush in Water-Rich Tunnels Based on Random Forest Algorithm
by Nian Zhang, Mengmeng Niu, Fei Wan, Jiale Lu, Yaoyao Wang, Xuehui Yan and Caifeng Zhou
Appl. Sci. 2024, 14(2), 867; https://doi.org/10.3390/app14020867 - 19 Jan 2024
Cited by 1 | Viewed by 573
Abstract
To prevent large-scale water inrush accidents during the excavation process of a water-rich tunnel, a method, based on a random forest (RF) algorithm, for predicting the hazard level of water inrush is proposed. By analyzing hydrogeological conditions, six factors were selected as evaluating [...] Read more.
To prevent large-scale water inrush accidents during the excavation process of a water-rich tunnel, a method, based on a random forest (RF) algorithm, for predicting the hazard level of water inrush is proposed. By analyzing hydrogeological conditions, six factors were selected as evaluating indicators, including stratigraphic lithology, inadequate geology, rock dip angle, negative terrain area ratio, surrounding rock grade, and hydrodynamic zonation. Through the statistical analysis of 232 accident sections, a dataset of water inrush accidents in water-rich tunnels was established. We preprocessed the dataset by detecting and replacing outliers, supplementing missing values, and standardizing the data. Using the RF model in machine learning, an intelligent prediction model for the hazard of water inrush in water-rich tunnels was established through the application of datasets and parameter optimization processing. At the same time, a support vector machine (SVM) model was selected for comparison and verification, and the prediction accuracy of the RF model reached 98%, which is higher than the 87% of the SVM. Finally, the model was validated by taking the water inrush accident in the Yuanliangshan tunnel as an example, and the predicted results have a high degree of consistency with the actual hazard level. This indicates that the RF model has good performance when predicting water inrush in water-rich tunnels and that it can provide a new means by which to predict the hazard of water inrush in water-rich tunnels. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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18 pages, 3919 KiB  
Article
Statistical Characteristics of Stress Changes in Tunnel Surrounding Rock Based on Random Discrete Variability of Geotechnical Materials
by Rong Jiang, Zhao Yang, Song Chen, Ying Yuan and Liang Liu
Appl. Sci. 2023, 13(24), 12986; https://doi.org/10.3390/app132412986 - 05 Dec 2023
Viewed by 520
Abstract
In the construction of underground engineering, the determination of surrounding rock stresses has important theoretical significance for the design of tunnel structure reliability. In this paper, the nonlinear criterion is introduced to modify and improve the friction resistance in the calculation formula of [...] Read more.
In the construction of underground engineering, the determination of surrounding rock stresses has important theoretical significance for the design of tunnel structure reliability. In this paper, the nonlinear criterion is introduced to modify and improve the friction resistance in the calculation formula of Bierbaumer’s loose surrounding rock stresses, and the improved application is carried out in view of the situation of composite formation. Due to the variability and discreteness of geotechnical parameters, combined with engineering examples, Monte Carlo random sampling is carried out for various geotechnical parameters in engineering, and the characteristics of loose surrounding rock stresses are analyzed from the perspective of statistical reliability by using the improved shallow tunnel formula. By using the standard regression coefficient, the weight influence of the parameters in various shallow surrounding rock stress formulas is analyzed, and the confidence degree of the calculated results of various formulas is analyzed from a statistical point of view, which verifies the rationality of the improved formula in the statistical sense. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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22 pages, 10053 KiB  
Article
Pressure Model Study on Synchronous Grouting in Shield Tunnels Considering the Temporal Variation in Grout Viscosity
by Jun Ma, Ao Sun, Annan Jiang, Naisheng Guo, Xiang Liu, Jinliang Song and Tiexin Liu
Appl. Sci. 2023, 13(18), 10437; https://doi.org/10.3390/app131810437 - 18 Sep 2023
Viewed by 788
Abstract
The grout pressure in the shield tunnel tail void during synchronous grouting is the key to controlling ground settlement and restraining the segment. However, the circumferential, longitudinal, and radial distribution of grout pressure considering the temporal variation in grout viscosity has not been [...] Read more.
The grout pressure in the shield tunnel tail void during synchronous grouting is the key to controlling ground settlement and restraining the segment. However, the circumferential, longitudinal, and radial distribution of grout pressure considering the temporal variation in grout viscosity has not been well explored yet. In this study, a theoretical model of grout pressure distribution and dissipation considering the temporal variation in Bingham grout viscosity was established. The simulation results of the pressure model were verified by field-measured data. The results showed that the radial and longitudinal distributions of grout pressure considering the temporal variation in grout viscosity were closer to the field-measured data. The impacts of the main parameters on the pressure distribution and dissipation were analyzed. Compared with the effect of the shield tail void thickness, tunnel radius and yield shear stress have greater effects on grout pressure during the circumferential filling phase. During the longitudinal and radial diffusion phases, the increase in soil porosity and permeability coefficient was conducive to grout diffusion. The increase in the grout viscosity reduces the pressure loss during the grout flow process. The results of this research can provide a theoretical basis for the grout design process in shield tunnels. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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17 pages, 3980 KiB  
Article
BIM-Based Optimization of Drilling Angle and Hole Position of Outside Corner Anchor Rods
by Zihan Jiao, Xuefeng Zhao, Danyang Li, Zhe Sun and Wangbing Li
Appl. Sci. 2023, 13(15), 9014; https://doi.org/10.3390/app13159014 - 07 Aug 2023
Viewed by 957
Abstract
In recent years, safety issues involving foundation pits have attracted extensive attention in the industry. The external angle of the foundation pit bears a greater load and is more prone to collapsing. Anchor support technology is one of the most widely used support [...] Read more.
In recent years, safety issues involving foundation pits have attracted extensive attention in the industry. The external angle of the foundation pit bears a greater load and is more prone to collapsing. Anchor support technology is one of the most widely used support technologies in construction engineering, but it has the problem of anchor rod crossing and colliding from the initial design stage, and this reduces anchoring force and eventually leads to many safety issues. Compared with traditional methods, Building Information Modeling (BIM) technology can save a lot of time as well as reduce costs, and applying it to concealed engineering can solve the problems that exist during the design stage and reduce unpredictable construction risks. This study proposes an optimization method based on BIM that can accurately and quickly optimize the drilling of anchor rods in the external angles of foundation pits. The results show that the proposed method can reduce the number of anchor rod collision points at the external angle of the foundation pit, minimize the loss of horizontal force caused by anchor rod collision, and ensure the safety and stability of the foundation pit support system. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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14 pages, 4684 KiB  
Article
Research on Deformation and Loose Zone Characteristics of Large Cross Section Tunnel in High Geo-Stress Soft Rock
by Dong Ma, Zhongsheng Tan, Linlin Bian, Baojin Zhang and Jinpeng Zhao
Appl. Sci. 2023, 13(15), 9009; https://doi.org/10.3390/app13159009 - 06 Aug 2023
Viewed by 906
Abstract
In constructing high-geo-stress soft rock tunnels, the major deformation disaster of the surrounding rock has always been the main problem faced during construction. The research on the deformation and loose zone characteristics of large deformation tunnels has positive significance for the safe and [...] Read more.
In constructing high-geo-stress soft rock tunnels, the major deformation disaster of the surrounding rock has always been the main problem faced during construction. The research on the deformation and loose zone characteristics of large deformation tunnels has positive significance for the safe and rapid construction of tunnels. Therefore, based on the Yuntunpu large deformation tunnel, this article first analyzes the geological and deformation characteristics of the tunnel site area in response to the problem of high-geo-stress soft rock large deformation. Subsequently, on-site testing and analysis were conducted on the loose zone characteristics of four tunnel sections. Finally, based on the comprehensive analysis of tunnel deformation and loose zone characteristics, the causes of large deformation in the tunnel are analyzed. The results indicate that the large deformation characteristics of the Yuntunpu Tunnel are mainly manifested as a large initial deformation rate of the surrounding rock, a short self-stabilization time of the surrounding rock, a large cumulative deformation amount, and a long deformation duration. The Yuntunpu Tunnel is influenced by the grade and structure of the surrounding rock, with a loosening zone ranging from 12 to 14 m, and the wave velocity variation characteristics exhibited by different grades of surrounding rock vary greatly. Adopting collaborative active control of long and short anchor rods is recommended to limit the continued development of loose zones and the deformation of surrounding rocks. The large deformation of tunnels is mainly affected by high geo-stress, formation lithology, geological structure, engineering disturbance, and groundwater. Among them, high geo-stress and formation lithology are the decisive and important factors for the occurrence of major deformation disasters in the tunnel. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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17 pages, 12122 KiB  
Article
Impact Analysis and Optimization of Key Material Parameters of Embedded Water-Stop in Tunnels
by Lin Wang, Chao Guan, Yimin Wu and Chengkui Feng
Appl. Sci. 2023, 13(14), 8468; https://doi.org/10.3390/app13148468 - 22 Jul 2023
Viewed by 749
Abstract
Leakage diseases frequently occur in mountain tunnels, and the lining joints are weak waterproof links. In order to solve the problems such as insufficient waterproof technology for existing tunnel joints, this paper relies on the scientific and technological project of the Hubei Provincial [...] Read more.
Leakage diseases frequently occur in mountain tunnels, and the lining joints are weak waterproof links. In order to solve the problems such as insufficient waterproof technology for existing tunnel joints, this paper relies on the scientific and technological project of the Hubei Provincial Department of Transportation to optimize the key parameters of the tunnel water-stop material and uses numerical simulation methods to analyze the impact of the hardness of the water-stop and the bond strength between the water-stop and concrete on its deformation and waterproof ability. Through the adhesion test, the optimization method of the bond strength between the water-stop and concrete is explored. The results show that: (1) the deformation stress of the water-stop will increase with the increase in hardness and reducing the hardness of the water-stop can improve its stress deformation state. Considering that low hardness increases the risk of damage and reduces the quality, it is recommended that the hardness be 55–60 (HA). (2) The adhesion between the water-stop and the concrete lining is the key to waterproofing the water-stop. Increasing the adhesion between the water-stop and the concrete is an effective optimization method. However, to prevent excessive deformation stress, it is necessary to optimize the geometric structure of the water-stop simultaneously. (3) Placing an epoxy–quartz sand coating on the surface of the water-stop can increase the adhesive force between the water-stop and the concrete. When the thickness of the epoxy layer is 2 mm, and the particle size of quartz sand is 26–40 mesh, the effect is best. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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22 pages, 13648 KiB  
Article
Research on Construction Sequences and Construction Methods of the Small Clear-Distance, Double-Arch Tunnel under an Asymmetrical Load
by Shan Wu, Jian Wu and Dunwen Liu
Appl. Sci. 2023, 13(14), 8242; https://doi.org/10.3390/app13148242 - 16 Jul 2023
Cited by 1 | Viewed by 790
Abstract
A small clear-distance, double-arch tunnel under an asymmetrical load combines the characteristics of small clear-distance, tunnels and double-arch tunnels, and the influence of an asymmetrical terrain must be considered. Its construction stability is a problem worth studying. This paper used the Wengcun tunnel [...] Read more.
A small clear-distance, double-arch tunnel under an asymmetrical load combines the characteristics of small clear-distance, tunnels and double-arch tunnels, and the influence of an asymmetrical terrain must be considered. Its construction stability is a problem worth studying. This paper used the Wengcun tunnel as the engineering background. Midas/GTS finite element analysis software was used to study the effects of eight excavation sequences and two excavation methods on tunnel stability. The results showed that the deformation and force of the tunnel were asymmetric under the asymmetrical terrain. Both middle partition walls were deformed towards the shallowly buried side, and the shallowly buried side was deformed to a greater extent. Excavating shallow side tunnels first can effectively mitigate the impact of asymmetric terrain. The arch settlement of the Center Diaphragm Excavation Method is 1.33 cm, which is smaller than the three-step excavation method of 1.48 cm; however, this difference is not significant. The Three-bench Excavation Method was more efficient. Based on the conclusion of a numerical simulation, the construction site adopted the construction sequence of excavating the shallowly buried side tunnel first and adjusted the excavation method to the Three-bench Excavation Method. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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16 pages, 10757 KiB  
Article
Airtightness Sealing Performance and Failure Mechanism of the Circumferential Joint in the Low-to-Vacuum Maglev Segment Tunnel
by Jianjun Zhou, Long Shi, Dongyuan Wang and Kai Cui
Appl. Sci. 2023, 13(13), 7535; https://doi.org/10.3390/app13137535 - 26 Jun 2023
Viewed by 753
Abstract
Segment lining structure is one of the choices to be used for low-to-vacuum maglev tunnels in the future. The airtightness at the joints of the lining structures is one of the critical problems that need to be addressed. However, little attention has been [...] Read more.
Segment lining structure is one of the choices to be used for low-to-vacuum maglev tunnels in the future. The airtightness at the joints of the lining structures is one of the critical problems that need to be addressed. However, little attention has been devoted to this problem until now. In this paper, a new apparatus was invented and used to study the mechanical behavior and airtightness sealing capacity of the gasket-in-groove, and a finite element analysis (FEA) model, validated by the test, was developed and used to further investigate thoroughly the sealing performance and sealing failure mechanism of the gasket-in-groove. The results obtained by the above two methods were discussed and compared, and a series of findings were presented. The results showed that the initial pressure distribution on the gasket–gasket contact surface is not uniform due to the presence of the inner holes in the gasket and the grooves between the gasket legs and an approximate “W” shape distribution in this study. The effect of vacuum pressure on the contact pressure distribution is very significant and shows an overall decreasing trend with increasing vacuum pressure. A higher initial maximum contact pressure would provide a better sealing effect but a lower sealing safety factor. Airtightness failure induced by evacuation is a contact surface separation process in which the maximum contact pressure shows a tendency to rise sharply with vacuum pressure increases, followed by a slow drop, and then declines dramatically to zero. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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18 pages, 9823 KiB  
Article
Numerical Simulation Method for Tunnel Excavation Considering Mechanical Characteristic Variation of Soft Rock with the Confining Pressure Influence
by Yucang Dong, Hai Zhang, Zhengguo Zhu and Yongquan Zhu
Appl. Sci. 2023, 13(12), 7305; https://doi.org/10.3390/app13127305 - 19 Jun 2023
Cited by 1 | Viewed by 1113
Abstract
The accurate prediction and evaluation of stress and displacement fields of surrounding rock is the fundamental premise for the deformation control of soft rock tunnels under high geo-stress condition. However, due to the complicated mechanical characteristics of soft rock with confining pressure influence, [...] Read more.
The accurate prediction and evaluation of stress and displacement fields of surrounding rock is the fundamental premise for the deformation control of soft rock tunnels under high geo-stress condition. However, due to the complicated mechanical characteristics of soft rock with confining pressure influence, the current numerical simulation method usually regards the mechanical parameters of surrounding rock as constant and ignores the variation of these parameters in the simulation process, which leads to results that cannot accurately reflect the mechanical behavior of surrounding rock. Therefore, this paper firstly investigates the effect of confining pressure on deformation and strength parameters for soft rock and proposes corresponding variable models for mechanical parameters with the confining pressure influence. Secondly, a transversal loop discriminant update procedure is proposed and introduced into the iteration calculation process of FLAC3D, thus forming an improved numerical simulation method. This improved method can integrally consider the mechanical parameter variation of surrounding rock with variable confining pressure and realize the automatic update for such a parameter with its variable stress state. Finally, as an application example, an improved expression of longitudinal deformation profile (LDP) for tunnels considering the confining pressure influence is proposed based on numerous simulation results for a soft rock tunnel obtained by this proposed method. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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20 pages, 8055 KiB  
Article
Slurry Discharge Pipeline Damage and Wear Due to Transporting Rock Particles during Slurry Shield Tunneling: A Case Study Based on In Situ Observed Results
by Xinggao Li, Yingran Fang, Yidong Guo and Xingchun Li
Appl. Sci. 2023, 13(12), 7103; https://doi.org/10.3390/app13127103 - 14 Jun 2023
Viewed by 1218
Abstract
Rock particles in excavated materials can damage and wear down slurry discharge pipelines when slurry shield tunneling occurs in a pebble layer and rock ground. This pipeline damage and wear, if not properly dealt with, can lead to a broken-down tunneling machine. Based [...] Read more.
Rock particles in excavated materials can damage and wear down slurry discharge pipelines when slurry shield tunneling occurs in a pebble layer and rock ground. This pipeline damage and wear, if not properly dealt with, can lead to a broken-down tunneling machine. Based on a slurry shield tunneling project in China, damage and wear were thoroughly examined. The observed pipeline wear and leaks, transported rock particles, mechanical properties, and flow rate of the carrier slurry were presented. The measured results showed that the wear rates of a straight pipe, a pipe along a curved tunnel, a 60° inclined pipe, and a 90° elbow pipe in pebble ground were approximately 0.71 mm/100 rings, 1 mm/100 rings, 2.14 mm/100 rings, and 4 mm/100 rings, respectively. When the machine drove into rock ground, the wear rates increased by one to two times, which could be attributed to the sharper particle shapes. Countermeasures to address these issues, such as adjusting the pipeline layout, welding reinforcement plates in advance, and preparing additional pipes, were highlighted. The wear rates of different types of pipes, the effectiveness of new pipeline fixing methods, and the probability of pipeline leaks in different strata were discussed in detail. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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21 pages, 9854 KiB  
Article
Calculation Method of Loose Pressure in Surrounding Rock Mass
by Hongjie Gao, Weibin Ma, Wenhao Zou, Jinlong Zhang, Xinyu Li and Jiaqiang Han
Appl. Sci. 2023, 13(10), 6334; https://doi.org/10.3390/app13106334 - 22 May 2023
Cited by 1 | Viewed by 930
Abstract
With the implementation of the regional coordinated development strategy, traffic flow has grown explosively. The construction of a larger tunnel section becomes an effective way to solve the highway network’s insufficient transport capability problem. Currently, there is little research on the factors influencing [...] Read more.
With the implementation of the regional coordinated development strategy, traffic flow has grown explosively. The construction of a larger tunnel section becomes an effective way to solve the highway network’s insufficient transport capability problem. Currently, there is little research on the factors influencing and methods of calculating the loose pressure in the surrounding rock mass for highway tunnels with super-large cross-sections. Based on the Bifurcation Tunnel, which is one of the sign projects in the past five years, this paper discusses the influencing factors for the range of loose zone in deeply buried tunnels using a combination of a numerical analysis and an orthogonal test. The weight of influencing factors is calculated via an efficiency evaluation method. This paper establishes a limit analysis model of the loose pressure in the surrounding rock mass under a non-linear failure criterion based on the fitted boundary function and upper bound limit analysis method and deduces the correlations of the loose pressure. The distribution law of the loose pressure, obtained via the limit analysis method, is consistent with the pressure-monitoring results, verifying the correctness of the proposed calculation method. This study can provide a calculation basis for the design of a supporting structure and the selection of similar super-section tunnel projects. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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14 pages, 2691 KiB  
Article
Study on the Effects of Different Water Content Rates on the Strength and Brittle Plasticity of Limestone
by Quan Zhang, Yuanming Liu, Guohua He, Qingzhi Chen, Xun Ou and Jiao Tian
Appl. Sci. 2023, 13(8), 4685; https://doi.org/10.3390/app13084685 - 07 Apr 2023
Cited by 1 | Viewed by 1260
Abstract
Water can deteriorate the compositional properties of rock through softening and dissolution. The water content rate of rock has a certain effect and can cause changes in rock properties caused by the water action. In this research, to study the effects of the [...] Read more.
Water can deteriorate the compositional properties of rock through softening and dissolution. The water content rate of rock has a certain effect and can cause changes in rock properties caused by the water action. In this research, to study the effects of the water content rate on the strength and brittle plasticity of limestone, uniaxial compression tests with different water content rate states were conducted, and the form of limestone damage under different water content rate conditions was analyzed. The effects of the different water content rates on the modulus of elasticity, uniaxial compressive strength, brittleness index B value, and brittleness correction index BIM value (BIM: the ratio of dissipated strain energy to releasable elastic strain energy at the peak point of the specimen) of limestone were investigated. It was found that as the rate of water content in the limestone increased from 0% to 0.27%, the penetration shear surface on the limestone’s damaged surface decreased. The modulus of elasticity decreased from 8.85 to 6.76 GPa, the uniaxial compressive strength decreased from 74.11 to 57.60 MPa, the brittleness index B value decreased from 1.17 to 1.04, and the brittleness correction index BIM value increased from 0.09 to 0.26. As the rate of water content on the limestone increased, the rock’s modulus of elasticity and uniaxial compressive strength decreased. Additionally, the rock’s brittleness decreased, and the percentage of plastic deformation in the total deformation increased. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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29 pages, 19797 KiB  
Article
Study of the Behavior of Excavations and Support Systems for an Alternative Construction Model of the Tunnels in Mexico City
by Antonio Alonso-Jiménez, José Francisco Suárez-Fino, Manuel Regueiro y González-Barros and Carlos López-Jimeno
Appl. Sci. 2023, 13(6), 3601; https://doi.org/10.3390/app13063601 - 11 Mar 2023
Viewed by 1227
Abstract
The project proposal for the Desierto de los Leones tunnels in the Poetas Highway in Mexico aims to improve the excavation and support systems and evaluate the safety levels during construction. The design is based on geological and geotechnical information from the original [...] Read more.
The project proposal for the Desierto de los Leones tunnels in the Poetas Highway in Mexico aims to improve the excavation and support systems and evaluate the safety levels during construction. The design is based on geological and geotechnical information from the original project and can be approached using various methods, including numerical simulations. The article includes a summary of the lithological characteristics, a reinterpretation of geotechnical properties, a description of new construction procedures, and the results of calculations using the finite data differences method. The proposed project aims to improve the safety and stability of the tunnels through advanced construction technologies and adapted procedures, generated by a redesign and the scientific application of new techniques developed for this project. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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20 pages, 11934 KiB  
Article
Deformation Characteristics and Grouting Control Technology of Reused Roadway in a Fully Mechanized Coalface with Large Mining Height
by Leilei Zhao, Zhendong Cui, Ruidong Peng, Tao Wei, Longcan Wang and Dongxu Liu
Appl. Sci. 2023, 13(3), 1951; https://doi.org/10.3390/app13031951 - 02 Feb 2023
Cited by 1 | Viewed by 1078
Abstract
Reused roadways are increasingly adopted in fully mechanized coalfaces with large mining heights because of the ventilation and gas drainage problems. However, the forced mechanism and grouting control technology of the reused roadway was seldom studied. Hence, in this paper, field monitoring and [...] Read more.
Reused roadways are increasingly adopted in fully mechanized coalfaces with large mining heights because of the ventilation and gas drainage problems. However, the forced mechanism and grouting control technology of the reused roadway was seldom studied. Hence, in this paper, field monitoring and numerical simulation were undertaken to investigate the distribution of stress and deformation of the reused roadway, and the reasonable grouting opportunities and technological parameters were determined accordingly. Engineering application of grouting control technology with self-developed inorganic double-fluid grouting materials was conducted. The field monitoring and numerical simulation revealed that the reused roadway was significantly affected by the lateral abutment pressure during the first mining operation and by the leading abutment pressure during the second mining operation. It was characterized by lagging stable deformation during the first mining operation and ceaselessly increasing deformation during the second mining operation. The deformation range of the reused roadway during the first mining operation can be divided into three stages: initial deformation, violent deformation and plateaued deformation, while the deformation range can be divided into three distinct stages: initial deformation, slow deformation and violent deformation during the second mining operation. On the basis of the roadway deformation law, two grouting opportunities were confirmed. The first grouting opportunity was suggested in the front part of the plateaued deformation stage during the first mining. The second grouting opportunity was suggested in the slow deformation stage during the second mining. Field engineering applications showed that both the deformation range and value of the reused roadway were decreased obviously after grouting. Full article
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34 pages, 11432 KiB  
Article
A Numerical Investigation to Calculate Ultimate Limit State Capacity of Cable Bolts Subjected to Impact Loading
by Faham Tahmasebinia, Adam Yang, Patrick Feghali and Krzysztof Skrzypkowski
Appl. Sci. 2023, 13(1), 15; https://doi.org/10.3390/app13010015 - 20 Dec 2022
Cited by 15 | Viewed by 1759
Abstract
As rock bursts are unavoidable in deep mines and excavations with high in-situ stresses, ground support systems are implemented to manage and mitigate rock bursts. Cable bolts are commonly used as reinforcing elements in ground support systems, which are subject to dynamic loads [...] Read more.
As rock bursts are unavoidable in deep mines and excavations with high in-situ stresses, ground support systems are implemented to manage and mitigate rock bursts. Cable bolts are commonly used as reinforcing elements in ground support systems, which are subject to dynamic loads in burst-prone excavations. To design an efficient cable bolt in burst-prone conditions, shear and energy absorption capacity must be considered. Numerical modelling is an advantageous method of repeatable testing and it is inexpensive and non-destructive. This study develops a statically and dynamically loaded numerical model of a double shear test in ABAQUS/Explicit. A total of 36 static and 576 dynamic tests are carried out, which examine the influence of bolt diameter, steel yield and ultimate strength, dynamic load velocity and dynamic load mass on the displacement, shear force and energy absorption capacity of cable bolts. As bolt diameter and steel yield strength increases, the maximum shear force resisted and bolt displacement increases. Similarly, as the mass and velocity of the dynamic load increases, the amount of energy absorbed by the cable bolt increases. The main novelty of the current research is to suggest a reliable computational tool to investigate the influence of the different key parameters in the cable bolts on the ultimate capacity. The suggested method is a significantly cost-effective technique compared with the experimental investigations. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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19 pages, 7054 KiB  
Article
Study on Fire Smoke Distribution and Safety Evacuation of Subway Station Based on BIM
by Nian Zhang, Yan Liang, Caifeng Zhou, Mengmeng Niu and Fei Wan
Appl. Sci. 2022, 12(24), 12808; https://doi.org/10.3390/app122412808 - 13 Dec 2022
Cited by 7 | Viewed by 1843
Abstract
A subway station is a confined space, so it is very important to evacuate people safely in case of a fire. It is necessary to study and analyze the smoke distribution and evacuation ability of different station layout schemes when fire occurs. Taking [...] Read more.
A subway station is a confined space, so it is very important to evacuate people safely in case of a fire. It is necessary to study and analyze the smoke distribution and evacuation ability of different station layout schemes when fire occurs. Taking a subway station as an example, this paper combines BIM (Building Information Model) technology with the fire safety evacuation of the subway station. First, we optimize the layout of the public area of the subway station and use BIM technology to establish a subway station model. Then, we use the PyroSim software to establish a subway station fire model to analyze fire development in different locations of the station in the optimization scheme, and determine the time it takes for CO concentration, smoke temperature and visibility to reach the critical value of danger. Finally, a subway station fire evacuation model is established using the Pathfinder software to study the safety evacuation of people in the subway station fire. The results show that it takes the shortest time for the visibility in the station to reach the critical value under fire conditions, and the threat to safety evacuation is the greatest. The available safe evacuation time of the optimized subway station is greater than the required safe evacuation time under different fire conditions, that is, the optimized subway station arrangement can ensure the safety evacuation of the personnel in the subway station under fire conditions. The research results can serve as reference for the optimization of safety evacuation designs of similar subway stations. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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22 pages, 10200 KiB  
Article
Sensitivity Analysis of Influencing Factors of Underground Civil Air Defense Construction Vibration under Vehicle Load
by Yangyong Wu, Chaomin Mu, Hui Zhang and Hui Zhou
Appl. Sci. 2022, 12(23), 12361; https://doi.org/10.3390/app122312361 - 02 Dec 2022
Cited by 1 | Viewed by 949
Abstract
Grey correlation theory is an uncertainty analysis method, which can find the relevance of various factors studied through certain data processing in incomplete information and find the main influencing factors. In order to study the influence of vehicle load on the vibration of [...] Read more.
Grey correlation theory is an uncertainty analysis method, which can find the relevance of various factors studied through certain data processing in incomplete information and find the main influencing factors. In order to study the influence of vehicle load on the vibration of underground civil air defense construction, taking the civil air defense construction at the intersection of Zhongzhou Middle Road and Shachang South Road in Luoyang as the study subject, based on the field measured data, and using ANSYS to expand the working conditions, this paper studies the influence of such factors as elastic modulus of concrete, thickness of overburden layer, density of soil layer, elastic modulus of soil layer, vehicle speed, and vehicle mass on the vibration of the civil air defense construction through the grey correlation sensitivity analysis method. The field measurement and numerical simulation results show that the displacement, velocity, and acceleration values decrease gradually from the mid−span position of the roof to the wall. Displacement, velocity, and acceleration are important indexes for evaluating vibration. The grey correlation degree of the influencing factors of displacement and velocity from large to small is density of soil layer, vehicle mass, vehicle speed, elastic modulus of concrete, elastic modulus of soil layer, and thickness of overburden layer. The grey correlation degree of the influencing factors of acceleration from large to small is vehicle mass, layer of density of soil layer, vehicle speed, elastic modulus of concrete, elastic modulus of soil layer, and thickness of overburden layer. The grey correlation degree of soil layer density, vehicle mass and vehicle speed to displacement, velocity, and acceleration is 0.7951–0.9993, which indicates that their influence is significant. This study can provide reference for the design and construction of similar civil air defense constructions. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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16 pages, 12719 KiB  
Article
Study on the Effects of Artificial Trapezoidal Freezing Soil Mass on the Stability of Large-Diameter Shield Tunnel Portal
by Shuai Peng, Feng Xiong, Fan Yang, Li Hu, Xuebin Wang and Fan Li
Appl. Sci. 2022, 12(23), 12250; https://doi.org/10.3390/app122312250 - 30 Nov 2022
Viewed by 990
Abstract
The shield tunnel end reinforcement is important in the water-rich sandy strata. In this paper, a trapezoidal freezing soil mass was proposed to reinforce the shield tunnel end, and the reinforcement effects were evaluated based on the Wuhu River-Crossing Tunnel. Firstly, the influences [...] Read more.
The shield tunnel end reinforcement is important in the water-rich sandy strata. In this paper, a trapezoidal freezing soil mass was proposed to reinforce the shield tunnel end, and the reinforcement effects were evaluated based on the Wuhu River-Crossing Tunnel. Firstly, the influences of the freezing soil mass geometric dimensions on the stability of the tunnel portal were analyzed. Then, displacements of the tunnel portal with different trapezoidal freezing soil masses were simulated. Finally, the trapezoidal freezing soil mass was applied in the Wuhu River-Crossing Tunnel. The results show that the portal’s stability is improved significantly with increased freezing soil mass longitudinal length if the length is less than the tunnel diameter. The lower side of the trapezoidal freezing soil mass has a greater influence on the tunnel portal stability than the upper side. The trapezoidal freezing soil mass is more effective than the rectangular freezing soil mass for the Wuhu River-Crossing Tunnel end reinforcement. The trapezoidal freezing soil mass is a good choice for the shield tunnel end soil reinforcement in water-rich sandy strata. This study provides a freezing reinforcement method for the large-diameter shield tunnel end, which provides guidelines for similar engineering. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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23 pages, 7207 KiB  
Article
Grouting for Tunnel Stability Control and Inadequate Grouting Section Recognition: A Case Study of Countermeasure of Giant Karst Cave
by Peng Peng, Feng Peng, Zhenyu Sun and Dingli Zhang
Appl. Sci. 2022, 12(23), 11895; https://doi.org/10.3390/app122311895 - 22 Nov 2022
Cited by 2 | Viewed by 1104
Abstract
Backfilling a giant karst cave with grouted engineering spoil as a new countermeasure for tunnels through giant karsts cave is studied in this paper. The numerical models of sections with different distribution characteristics of karst cave and tunnels are established for studying the [...] Read more.
Backfilling a giant karst cave with grouted engineering spoil as a new countermeasure for tunnels through giant karsts cave is studied in this paper. The numerical models of sections with different distribution characteristics of karst cave and tunnels are established for studying the deformation of surrounding rock and mechanical response of tunnel lining with and without grouting, respectively. The results illustrate that the countermeasure scheme is feasible. In order to ensure that the countermeasure can perform as expected effect, the inadequate grouting sections are recognized and verified using field grouting records and single-hole grouting quantity analysis. Finally, the application effect of the countermeasure scheme is evaluated by field monitoring of horizontal convergence. The result shows that the grouting can reduce the deformation of surrounding rock at the side wall and bottom of tunnel by 70–80% and reduce the stress redistribution range of surrounding rock. However, due to the great differences between the limestone and engineering spoil, the grouting cannot change the share of distribution of load between corresponding region surrounding rock, the max principle stress of tunnel lining is almost identical with and without grouting. The grouting reinforced engineering spoil backfill the giant karst cave can meet the requirement of excavation stability. The inadequate grouting sections caused by groundwater and through crack are identified effectively, and are verified by coring observation method. The horizontal convergence of the tunnel is less than 30 mm, and the stable state can be reached within 20 days, which demonstrate that the remarkable engineering results is achieved. The countermeasure of giant karst cave can provide a useful reference for similar project. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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17 pages, 666 KiB  
Article
Research on the Tunnel Boring Machine Selection Decision-Making Model Based on the Fuzzy Evaluation Method
by Zhongsheng Tan, Haixiang Lai, Zonglin Li, Zhenliang Zhou, Yifeng Jiao, Fengyuan Li and Liming Wang
Appl. Sci. 2022, 12(21), 10802; https://doi.org/10.3390/app122110802 - 25 Oct 2022
Cited by 3 | Viewed by 2152
Abstract
When the tunnel boring machine (TBM) construction method is used to build tunnels, if the type of TBM is not appropriate, problems, such as low construction efficiency and increased construction cost, will easily occur. Therefore, it is necessary to build a TBM selection [...] Read more.
When the tunnel boring machine (TBM) construction method is used to build tunnels, if the type of TBM is not appropriate, problems, such as low construction efficiency and increased construction cost, will easily occur. Therefore, it is necessary to build a TBM selection decision-making model to guide TBM selection. In this paper, seven evaluation indexes are selected according to engineering experience and expert suggestions, and the quantitative standards of each index are unified. The modified analytic hierarchy process (MAHP) method is used to determine the weight of each evaluation index. The technique for order preference by similarity to an ideal solution (TOPSIS) method is adopted as the decision-making method of TBM selection. Finally, a TBM selection decision-making model is proposed based on the above methods. In order to verify the reliability of the TBM selection decision-making model proposed in this paper, we selected three projects for case verification and compared them with the previous TBM selection methods. The results show that the decision-making results of the method proposed in this paper are good. Additionally, the method proposed in this paper is more comprehensive and accurate than the previous methods. The model proposed in this paper can provide better suggestions for TBM selection in the project planning stage. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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11 pages, 3806 KiB  
Article
Correction of Point Load Strength on Irregular Carbonaceous Slate in the Luang Prabang Suture Zone and the Prediction of Uniaxial Compressive Strength
by Jianjun Wang, Yang Yang, Zhongsheng Tan, Dongfeng Li and Qianli Liu
Appl. Sci. 2022, 12(18), 9147; https://doi.org/10.3390/app12189147 - 12 Sep 2022
Viewed by 1326
Abstract
Uniaxial compressive strength (UCS) testing requires high-quality core samples, which is a difficult task for weak, highly fractured, thinly bedded, foliated, and weathered rocks. In addition, it is time-consuming and expensive. Because of the good relationship between rock point load strength (PLS) and [...] Read more.
Uniaxial compressive strength (UCS) testing requires high-quality core samples, which is a difficult task for weak, highly fractured, thinly bedded, foliated, and weathered rocks. In addition, it is time-consuming and expensive. Because of the good relationship between rock point load strength (PLS) and UCS, the PLS could be used to estimate rock UCS quickly. The lump structure and layer structure of carbonaceous slate are revealed in the tunnels of the China–Laos Railway in the Laos Luang Prabang Suture Zone as one of the important factors leading to tunnel squeezing deformation and support structures. To reveal the relationship between the PLS and UCS of carbonaceous slate in the Luang Prabang Suture Zone, PLS tests and UCS tests of lump-structure carbonaceous slate (lamina plane inconspicuous) and layer-structure carbonaceous slate (lamina plane conspicuous) were performed. Results show that the Is(50) of lump-structure carbonaceous slate ranged from 0.06 MPa to 0.30 Mpa, the Is(50) of layer-structure carbonaceous slates which were loaded perpendicular to the lamina plane ranged from 0.64 MPa to 1.25 MPa, the Is(50) of layer-structure carbonaceous slates which were loaded parallel to the lamina plane ranged from 0.49 MPa to 0.71 MPa, and the correction power index m ranged from 0.42 to 0.51 with an average value of 0.47. Four correlation expressions of carbonaceous slate relationships between PLS and UCS were fitted by zero-intercept linear expression, nonzero intercept linear expression, power expression, and logarithmic expression, and the calculation results were compared with results calculated by the International Society of Rock Mechanics (ISRM) correlation equation. It is concluded that the correlation equation between UCS and PLS recommended by ISRM specifications easily causes soft rock strength overestimation, which affects the correct evaluation of the surrounding rock property and the structural design safety of tunnels and underground projects. The zero-intercept linear equation UCS = 18.45Is(50) has better goodness of fit and higher accuracy in predicting the UCS of the carbonaceous slate in the Luang Prabang Suture Zone. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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18 pages, 3562 KiB  
Article
Inversion and Analysis of the Initial Ground Stress Field of the Deep-Buried Tunnel Area
by Rongsen Yu, Zhongsheng Tan, Junpeng Gao, Xiuying Wang and Jinpeng Zhao
Appl. Sci. 2022, 12(18), 8986; https://doi.org/10.3390/app12188986 - 07 Sep 2022
Cited by 2 | Viewed by 1340
Abstract
The detailed analysis of the initial ground stress distribution law is an important work for the safety of tunnel construction and operation. Especially, the high ground stress phenomenon in the deep-buried tunnel area is common, which has a great impact on the tunnel [...] Read more.
The detailed analysis of the initial ground stress distribution law is an important work for the safety of tunnel construction and operation. Especially, the high ground stress phenomenon in the deep-buried tunnel area is common, which has a great impact on the tunnel construction. Based on the on-site measured ground stress data, the analysis of the initial ground stress field by numerical simulation and multiple linear regression is mainly described in this study. Following the comparison and selection of three coefficient estimation methods for the regression equation, the best regression method is selected for inversion and verification. The distribution characteristic of the initial ground stress at different buried depths of the tunnel line is obtained. The inversion results of the initial ground stress in a tunnel area, in China, show that the lateral pressure coefficient gradually decreases with the buried depth increasing, while the overall lateral pressure coefficient is in the range of 1.0–2.0, showing a more significant horizontal tectonic. At the area where the tunnel passes through the fault, a small amount of horizontal tectonic stress is released. The ratio of horizontal principal stress to vertical principal stress is smaller than that on both sides, which is different from the distribution characteristic of lateral pressure coefficient without the impact of fault. It shows that faults have a great influence on ground stress. The lateral pressure coefficient in the area near the fault must be determined according to the on-site measured results. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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Jump to: Research

19 pages, 6826 KiB  
Essay
Case Study of an Underpinning Pile Foundation for an Interval Tunnel Crossing an Existing Bridge
by Yuhang Zhou, Yuanming Liu, Qingzhi Chen, Xun Ou and Yingxiao Li
Appl. Sci. 2022, 12(24), 12566; https://doi.org/10.3390/app122412566 - 08 Dec 2022
Cited by 1 | Viewed by 1366
Abstract
When urban subway tunnels cross existing bridge pile foundations, having a pile foundation underpinning that ensures the safe operation of existing bridges while enabling the safe construction of subway tunnels is the focus of attention. This paper takes the running tunnel project from [...] Read more.
When urban subway tunnels cross existing bridge pile foundations, having a pile foundation underpinning that ensures the safe operation of existing bridges while enabling the safe construction of subway tunnels is the focus of attention. This paper takes the running tunnel project from Huaguoyuan West Station to Huaguoyuan East Station of Rail Transit Line 3 in Guiyang City, Guizhou Province as the background. The reasonableness and feasibility of the passive underpinning construction scheme for the Guihuang Viaduct was studied. The construction plan includes the following steps: underpinning pile construction, foundation pit excavation, the concreting of the underpinning bearing platform, and existing pile truncation. In order to ensure the structural safety of the existing viaduct during the construction of the pile foundation underpinning, a 3D numerical model of the construction of pile foundation underpinning and the whole process of tunnel construction was established. The settlement calculation results of the foundation pit and bridge pier were compared and analyzed with the field monitoring data to verify the accuracy of the numerical model. Further detailed analysis of the settlement of the bridge deck, the deformation of the existing piles, the axial forces of the existing piles, and the forces on the underpinning bearing platform was carried out. The results show that the bridge superstructure load can be transferred to the underpinning bearing platform smoothly after the existing pile truncation construction. The removal of obstacle piles during tunnel excavation has a very limited impact on the superstructure of the bridge, proving the reasonableness and feasibility of the construction plan. Full article
(This article belongs to the Special Issue Advances in Tunnel and Underground Construction)
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