Pub Date : 2025-01-17DOI: 10.1016/j.tust.2025.106391
Tao Yu, Kaichen Ying, Jianfeng Wang, Zhigang Yao, Yong Fang
There is no precedent for the construction of large-section double-arch tunnels in fly ash accumulation stratum in China. The fly ash stratum is characterized by a loose structure, poor cementation, and low bearing capacity, which present significant challenges in tunnel design and construction. Based on the Yanpingba tunnel project, this paper conducts a model test on a large-section double-arch tunnel crossing a fly ash accumulation stratum, analyzing the tunnel’s mechanical behavior under various sequential excavation methods. The results show a large settlement of the vault and upper stratum of the double-arch tunnel excavated in the fly ash accumulation stratum. In addition, the stratum can easily become unstable, so it is necessary to reinforce the stratum by grouting. Compared with the subsequent tunnel, the advance tunnel is more affected by excavation, and the risk of structural damage is higher. Compared with the central diaphragm (CD) method and the bench method, the single side drift method is more conducive to safe construction. A mid-partition wall can effectively reduce the settlement of the stratum, but it is easily deflected to the side by the bias pressure. Adding support on the side of the advance tunnel of the mid-partition wall is recommended.
{"title":"Stability evaluation of the sequential excavation method of large-section double-arch tunnel in fly ash accumulation stratum through physical model","authors":"Tao Yu, Kaichen Ying, Jianfeng Wang, Zhigang Yao, Yong Fang","doi":"10.1016/j.tust.2025.106391","DOIUrl":"10.1016/j.tust.2025.106391","url":null,"abstract":"<div><div>There is no precedent for the construction of large-section double-arch tunnels in fly ash accumulation stratum in China. The fly ash stratum is characterized by a loose structure, poor cementation, and low bearing capacity, which present significant challenges in tunnel design and construction. Based on the Yanpingba tunnel project, this paper conducts a model test on a large-section double-arch tunnel crossing a fly ash accumulation stratum, analyzing the tunnel’s mechanical behavior under various sequential excavation methods. The results show a large settlement of the vault and upper stratum of the double-arch tunnel excavated in the fly ash accumulation stratum. In addition, the stratum can easily become unstable, so it is necessary to reinforce the stratum by grouting. Compared with the subsequent tunnel, the advance tunnel is more affected by excavation, and the risk of structural damage is higher. Compared with the central diaphragm (CD) method and the bench method, the single side drift method is more conducive to safe construction. A mid-partition wall can effectively reduce the settlement of the stratum, but it is easily deflected to the side by the bias pressure. Adding support on the side of the advance tunnel of the mid-partition wall is recommended.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106391"},"PeriodicalIF":6.7,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-17DOI: 10.1016/j.tust.2025.106403
Chuyen Pham , Byung-Chan Kim , Hyu-Soung Shin
Discontinuity mapping on tunnel faces is crucial for assessing stability and determining the need for additional reinforcement during tunnel construction. The traditional manual mapping approach is time-consuming and error-prone, necessitating a more accurate and efficient approach. This study explores a novel approach using photogrammetry to reconstruct digital 3D models of tunnel faces, enabling comprehensive discontinuity characterization without any time restriction. Despite challenges in image data collection and processing procedures, photogrammetry proves to be a viable alternative to LiDAR scanning for reconstructing precise 3D models of tunnel faces. Additionally, a deep learning technique is proposed to automatically identify rock mass discontinuities departing from massive random fractures on the 3D tunnel face. Since working directly with 3D models in deep learning is still challenging, the 3D tunnel face model is projected into four 2D images (i.e., RGB, depth map, normal vector, and curvature images) encompassing all necessary information of the 3D model. Afterward, a 2D semantic segmentation deep learning model is trained to identify areas of discontinuity based on the projected multi-2D images. Finally, the identified discontinuities are re-projected onto the 3D model to accurately reflect their original 3D context. Our results indicate that the proposed approach not only automatically and accurately quantifies rock discontinuities but also minimizes subjectivity inherent in manual judgment.
{"title":"Deep learning-based identification of rock discontinuities on 3D model of tunnel face","authors":"Chuyen Pham , Byung-Chan Kim , Hyu-Soung Shin","doi":"10.1016/j.tust.2025.106403","DOIUrl":"10.1016/j.tust.2025.106403","url":null,"abstract":"<div><div>Discontinuity mapping on tunnel faces is crucial for assessing stability and determining the need for additional reinforcement during tunnel construction. The traditional manual mapping approach is time-consuming and error-prone, necessitating a more accurate and efficient approach. This study explores a novel approach using photogrammetry to reconstruct digital 3D models of tunnel faces, enabling comprehensive discontinuity characterization without any time restriction. Despite challenges in image data collection and processing procedures, photogrammetry proves to be a viable alternative to LiDAR scanning for reconstructing precise 3D models of tunnel faces. Additionally, a deep learning technique is proposed to automatically identify rock mass discontinuities departing from massive random fractures on the 3D tunnel face. Since working directly with 3D models in deep learning is still challenging, the 3D tunnel face model is projected into four 2D images (i.e., RGB, depth map, normal vector, and curvature images) encompassing all necessary information of the 3D model. Afterward, a 2D semantic segmentation deep learning model is trained to identify areas of discontinuity based on the projected multi-2D images. Finally, the identified discontinuities are re-projected onto the 3D model to accurately reflect their original 3D context. Our results indicate that the proposed approach not only automatically and accurately quantifies rock discontinuities but also minimizes subjectivity inherent in manual judgment.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106403"},"PeriodicalIF":6.7,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-17DOI: 10.1016/j.tust.2025.106398
Deming Xu , Yuan Wang , Jingqi Huang , Shujun Xu , Kun Zhou
Cutterhead torque reflects the obstruction extent of geological environment on the shield machine, and its prediction can assist operators to adjust control parameters to improve construction efficiency and avoid machine jamming. However, tunneling in complex geological or working conditions often results in high cutterhead torque fluctuations and noise, which seriously affects the accuracy of torque prediction. This study proposes a multi-step prediction model for cutterhead torque enhanced by adaptive denoising and encoder-decoder. In this model, a novel adaptive denoising method for cutterhead torque is employed to improve prediction accuracy under complex conditions. Moreover, by introducing encoder-decoder method, the processing capability for multi-time dimensional data and multi-step prediction performance of LSTM neural networks are further improved. The effectiveness of proposed model is verified through an application to the Heyan Road River Crossing project. The results of this study can assist operators in achieving precise adjustment of control parameters under complex conditions.
{"title":"Multi-step prediction model enhanced by adaptive denoising and encoder-decoder for shield machine cutterhead torque in complex conditions","authors":"Deming Xu , Yuan Wang , Jingqi Huang , Shujun Xu , Kun Zhou","doi":"10.1016/j.tust.2025.106398","DOIUrl":"10.1016/j.tust.2025.106398","url":null,"abstract":"<div><div>Cutterhead torque reflects the obstruction extent of geological environment on the shield machine, and its prediction can assist operators to adjust control parameters to improve construction efficiency and avoid machine jamming. However, tunneling in complex geological or working conditions often results in high cutterhead torque fluctuations and noise, which seriously affects the accuracy of torque prediction. This study proposes a multi-step prediction model for cutterhead torque enhanced by adaptive denoising and encoder-decoder. In this model, a novel adaptive denoising method for cutterhead torque is employed to improve prediction accuracy under complex conditions. Moreover, by introducing encoder-decoder method, the processing capability for multi-time dimensional data and multi-step prediction performance of LSTM neural networks are further improved. The effectiveness of proposed model is verified through an application to the Heyan Road River Crossing project. The results of this study can assist operators in achieving precise adjustment of control parameters under complex conditions.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106398"},"PeriodicalIF":6.7,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With increasing population growth and rapid urbanisation, humanity faces the urgent challenges of climate change, necessitating transformative actions in the infrastructure and energy sectors to ensure sustainability for future generations. The renewed global emphasis on developing and utilising hydropower, particularly through pumped hydro energy storage (PHES) systems, is pivotal in advancing the transition to Net Zero emissions. Tunnel Boring Machines (TBMs) are extensively employed in tunnel construction for the energy sector. However, several critical challenges persist throughout the lifecycle of these vital projects. These include the lifecycle assessment of the mechanical performance and embodied carbon of segmental linings, influenced by geometric factors such as tunnel alignment and diameter, fabrication patterns, and joint stiffness. Furthermore, the long-term hydro-mechanical performance of pressurised tunnel linings is significantly affected by variable internal water pressures and surrounding rock conditions. This paper proposes an integrated framework for TBM tunnel design, utilising multiple Levels of Detail (multi-LoD) Building Information Modelling (BIM) to systematically address these challenges and enhance the sustainability and resilience of underground infrastructure. Algorithms for both parametric modelling and pre-processing are developed to ensure the interoperability between BIM and numerical models. The mechanical response of segmented linings under various internal water pressure is investigated to analyse the composite behaviour of reinforced concrete segments, joints, lining gaps, secondary linings, and rock mass under internal pressure. The robustness of the framework is implemented into a use case analysing the deformation and waterproofing performance of a segmental lining structure under high internal pressure and complex geological conditions. Four cases with various reinforced concrete lining designs, featuring differing thicknesses of secondary linings and tunnel alignments, are analysed. Additionally, embodied carbon assessments are conducted for each case, and design optimisation is performed based on numerical modelling and sustainability assessment results. The integrated framework detailly illustrates how multi-LoD BIM, hydro-mechanical coupling, and embodied carbon accounting can be effectively combined to enhance the sustainability and efficiency of TBM tunnelling projects.
{"title":"Multi-LoD BIM integrated design framework for pressurised tunnel: Hydro-mechanical coupling simulation and sustainability assessment","authors":"Feng Xiao , Xilin Chen , Yimo Zhu , Ping Xie , Saeed Salimzadeh , Qian-Bing Zhang","doi":"10.1016/j.tust.2025.106404","DOIUrl":"10.1016/j.tust.2025.106404","url":null,"abstract":"<div><div>With increasing population growth and rapid urbanisation, humanity faces the urgent challenges of climate change, necessitating transformative actions in the infrastructure and energy sectors to ensure sustainability for future generations. The renewed global emphasis on developing and utilising hydropower, particularly through pumped hydro energy storage (PHES) systems, is pivotal in advancing the transition to Net Zero emissions. Tunnel Boring Machines (TBMs) are extensively employed in tunnel construction for the energy sector. However, several critical challenges persist throughout the lifecycle of these vital projects. These include the lifecycle assessment of the mechanical performance and embodied carbon of segmental linings, influenced by geometric factors such as tunnel alignment and diameter, fabrication patterns, and joint stiffness. Furthermore, the long-term hydro-mechanical performance of pressurised tunnel linings is significantly affected by variable internal water pressures and surrounding rock conditions. This paper proposes an integrated framework for TBM tunnel design, utilising multiple Levels of Detail (multi-LoD) Building Information Modelling (BIM) to systematically address these challenges and enhance the sustainability and resilience of underground infrastructure. Algorithms for both parametric modelling and pre-processing are developed to ensure the interoperability between BIM and numerical models. The mechanical response of segmented linings under various internal water pressure is investigated to analyse the composite behaviour of reinforced concrete segments, joints, lining gaps, secondary linings, and rock mass under internal pressure. The robustness of the framework is implemented into a use case analysing the deformation and waterproofing performance of a segmental lining structure under high internal pressure and complex geological conditions. Four cases with various reinforced concrete lining designs, featuring differing thicknesses of secondary linings and tunnel alignments, are analysed. Additionally, embodied carbon assessments are conducted for each case, and design optimisation is performed based on numerical modelling and sustainability assessment results. The integrated framework detailly illustrates how multi-LoD BIM, hydro-mechanical coupling, and embodied carbon accounting can be effectively combined to enhance the sustainability and efficiency of TBM tunnelling projects.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106404"},"PeriodicalIF":6.7,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-17DOI: 10.1016/j.tust.2024.106362
Kaihang Han , Zhiyuan Zhai , Xiangsheng Chen , Chengping Zhang , Jiann-Wen Woody Ju , Xiaohua Bao , Shuying Wang , Beibei Hou
The development of multifunctional and three-dimensional underground spaces is an effective approach to expanding human activity spaces in future megacities. It significantly enhances urban carrying capacity, disaster resilience, and robustness, reduces carbon emissions, and promotes harmonious coexistence between humans and nature. A methodology for evaluating the safety resilience of the existing tunnels induced by foundation pit excavation is proposed in this paper. Considering the technological and management factors, a detailed resilience index system is suggested. The composite performance Q of the studied system is consistently calculated by virtue of the combined weight method and the TOPSIS method. Specifically, the proposed Q is determined by the combination of QA (existing underground structures), QB (stratum), and QC (adjacent construction disturbance), each with different weights. Furthermore, a comprehensive assessment of resilience R is proposed from the perspective of maximal and cumulative damage in Q. The evaluation method was conducted on an engineering project, and the effects of the three-dimensional component of Q and the deformation limits of existing structures on the evaluation results are analyzed emphatically. The results indicate that as the deformation limits of existing structures become more strict, the Q and R decrease. The methodology proposed in this paper provides essential information for the safety resilience assessment and resilience enhancement of underground structures.
{"title":"A methodology for evaluating the safety resilience of the existing tunnels induced by foundation pit excavation","authors":"Kaihang Han , Zhiyuan Zhai , Xiangsheng Chen , Chengping Zhang , Jiann-Wen Woody Ju , Xiaohua Bao , Shuying Wang , Beibei Hou","doi":"10.1016/j.tust.2024.106362","DOIUrl":"10.1016/j.tust.2024.106362","url":null,"abstract":"<div><div>The development of multifunctional and three-dimensional underground spaces is an effective approach to expanding human activity spaces in future megacities. It significantly enhances urban carrying capacity, disaster resilience, and robustness, reduces carbon emissions, and promotes harmonious coexistence between humans and nature. A methodology for evaluating the safety resilience of the existing tunnels induced by foundation pit excavation is proposed in this paper. Considering the technological and management factors, a detailed resilience index system is suggested. The composite performance <em>Q</em> of the studied system is consistently calculated by virtue of the combined weight method and the TOPSIS method. Specifically, the proposed <em>Q</em> is determined by the combination of <em>Q</em><sub>A</sub> (existing underground structures), <em>Q</em><sub>B</sub> (stratum), and <em>Q</em><sub>C</sub> (adjacent construction disturbance), each with different weights. Furthermore, a comprehensive assessment of resilience <em>R</em> is proposed from the perspective of maximal and cumulative damage in <em>Q</em>. The evaluation method was conducted on an engineering project, and the effects of the three-dimensional component of <em>Q</em> and the deformation limits of existing structures on the evaluation results are analyzed emphatically. The results indicate that as the deformation limits of existing structures become more strict, the <em>Q</em> and <em>R</em> decrease. The methodology proposed in this paper provides essential information for the safety resilience assessment and resilience enhancement of underground structures.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106362"},"PeriodicalIF":6.7,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.tust.2025.106396
Zhigang Tao , Xiaotian Lei , Keyuan Liu , Ruixue Zhang , Xiaowei Fan , Mingjiu Cai
The support of fault tunnels is one of the key factors limiting tunnel construction. Prestressed anchor cables are proposed as a new type of support. However, there are few quantitative studies on tunnel excavation failure and support mechanisms. On the basis of the background of the tunnel in the Haidong fault fracture zone of the water diversion project in central Yunnan and using the excavation compensation method, a self-developed three-dimensional geomechanical model box is employed to conduct tunnel excavation tests. The displacement field, temperature field, stress field changes and mechanical mechanisms under the support of prestressed anchor cables are studied, and the support effect of high preload anchor cables is verified in practical engineering. The test results show that high pretightening force anchor cable support can better influence the self-bearing capacity of the surrounding rock. When overload failure occurs, bolts are subjected to brittle fracture failure, whereas anchor cables experience flexible bending deformation failure. The area enclosed by the characteristic curve of the surrounding rock after anchor cable support and that of the unsupported surrounding rock can be used as a potential quantitative representation method for the increase in the self-bearing capacity of the surrounding rock. Field monitoring results indicate that bolt support at nonfault locations and anchor cable support at fault locations have better effects on controlling surrounding rock deformation.
{"title":"A model test investigation on prestressed anchor cable support for the Haidong fault tunnel","authors":"Zhigang Tao , Xiaotian Lei , Keyuan Liu , Ruixue Zhang , Xiaowei Fan , Mingjiu Cai","doi":"10.1016/j.tust.2025.106396","DOIUrl":"10.1016/j.tust.2025.106396","url":null,"abstract":"<div><div>The support of fault tunnels is one of the key factors limiting tunnel construction. Prestressed anchor cables are proposed as a new type of support. However, there are few quantitative studies on tunnel excavation failure and support mechanisms. On the basis of the background of the tunnel in the Haidong fault fracture zone of the water diversion project in central Yunnan and using the excavation compensation method, a self-developed three-dimensional geomechanical model box is employed to conduct tunnel excavation tests. The displacement field, temperature field, stress field changes and mechanical mechanisms under the support of prestressed anchor cables are studied, and the support effect of high preload anchor cables is verified in practical engineering. The test results show that high pretightening force anchor cable support can better influence the self-bearing capacity of the surrounding rock. When overload failure occurs, bolts are subjected to brittle fracture failure, whereas anchor cables experience flexible bending deformation failure. The area enclosed by the characteristic curve of the surrounding rock after anchor cable support and that of the unsupported surrounding rock can be used as a potential quantitative representation method for the increase in the self-bearing capacity of the surrounding rock. Field monitoring results indicate that bolt support at nonfault locations and anchor cable support at fault locations have better effects on controlling surrounding rock deformation.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106396"},"PeriodicalIF":6.7,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.tust.2025.106380
Zhongjie Zhang , Ting Deng , Zhenhao Shi , Maosong Huang , Haoran Wang , Xiaoqiang Gu
Pipe jacking method has been increasingly employed in congested urban areas to construct large-scale underground structures (e.g., subway stations), given its advantages in minimizing interventions on adjacent infrastructures. Nevertheless, it remains challenging to assess the associated ground movements. In this work, we form a numerical model for evaluating the ground movements caused by large rectangular structures in soft clays. The salient features of the model rest on explicitly accounting for (1) continuous frictional sliding at pipe–soil interface and (2) small-strain stiffness of soils. The former is achieved by combining displacement-controlled approach (DCA) and finite sliding contact method, while the latter is included by using inter-granular strain (IGS) based constitutive model proposed by the authors. The built numerical model is applied to a case study of the construction of a subway station in Shanghai, where the model performance is assessed against actual field measurements. We utilize the numerical model to analyze the characteristics of ground movements and the roles played by pipe–soil interface friction and small-strain behavior of soils. Our analyses suggest that, compared with conventional construction methods, pipe–soil interface friction and convergence deformation of structure can be important factors for controlling ground movements associated with pipe-jacking.
{"title":"Evaluation of ground movements due to pipe-jacking process of large rectangular structures in soft clays","authors":"Zhongjie Zhang , Ting Deng , Zhenhao Shi , Maosong Huang , Haoran Wang , Xiaoqiang Gu","doi":"10.1016/j.tust.2025.106380","DOIUrl":"10.1016/j.tust.2025.106380","url":null,"abstract":"<div><div>Pipe jacking method has been increasingly employed in congested urban areas to construct large-scale underground structures (e.g., subway stations), given its advantages in minimizing interventions on adjacent infrastructures. Nevertheless, it remains challenging to assess the associated ground movements. In this work, we form a numerical model for evaluating the ground movements caused by large rectangular structures in soft clays. The salient features of the model rest on explicitly accounting for (1) continuous frictional sliding at pipe–soil interface and (2) small-strain stiffness of soils. The former is achieved by combining displacement-controlled approach (DCA) and finite sliding contact method, while the latter is included by using inter-granular strain (IGS) based constitutive model proposed by the authors. The built numerical model is applied to a case study of the construction of a subway station in Shanghai, where the model performance is assessed against actual field measurements. We utilize the numerical model to analyze the characteristics of ground movements and the roles played by pipe–soil interface friction and small-strain behavior of soils. Our analyses suggest that, compared with conventional construction methods, pipe–soil interface friction and convergence deformation of structure can be important factors for controlling ground movements associated with pipe-jacking.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106380"},"PeriodicalIF":6.7,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.tust.2025.106389
Yajian Shao , Guowei Ma , Wei Zhang
Hydro-geomechanical model test is a prevailing method to study the seepage field in the underground engineering. Most of the existing test models are equivalent continuous medium models, whereas the deeply buried diversion tunnel in rock-matrix with fractures in practical engineering exhibit discontinuities, unevenness and heterogeneousness. To this gap, current study constructs an 1800.0 × 1800.0 × 1800.0 mm3 division tunnel model with fractures in the surrounding rock through 3D additive-subtractive printing, which registers the largest ever 3D printing hydro-geomechanical test model. The current model is based on a practical project of the Jinping II Hydropower Station. The geological strata along the longitudinal direction of the tunnel are surveyed to identify the most critical section in view of instability. Six major cracks in the critical section are identified and measured. According to the scalability principle in the fluid–solid coupling theory, the current model with dimension, density, and permeability scalability coefficients of respective 35, 1, and to those of the prototype target section is designed and 3D printed. In this 3D printed model, the dip angle and direction of the six major fractures are reproduction of those of the practical fractures, while the locus spacing is reduced by a scale of 35. Structural matrix is additively printed using cement mortar, while fractures are subtractive printed with a customized cutter. The fracture space is filled with a paste medium with variable permeabilities to approach the potential permeability range in the practical fractures. To reproduce the practical hydraulic-mechanical condition in the test, the 3D model is loaded with initial stresses of 150.0 kPa and seepage condition of 20.0 kPa around the model for 7 days prior to the hydraulic loading. To cover the potential practical seepage extent, the external hydraulic pressure is set gradually at five loading levels of 40.0 kPa, 60.0 kPa, 80.0 kPa, 100.0 kPa and 120.0 kPa. The results show that, as the circulating hydraulic pressure increases, the seepage pressure inside the fracture plane and outside the lining structure gradually increases. Test results are in good agreement with the field monitoring data. There is a significant correlation between the seepage pressure in different inclination planes and the distribution characteristics of fractures in its surrounding rock. With denser fractures in the surrounding rock on the lining outside, the seepage pressure in this area will be higher. The test results reflect the discontinuity characteristics of the seepage field inside the fractured rock mass to provide guidance for the stability evaluation and long-term maintenance of water diversion tunnel engineering.
{"title":"Large-scale 3D printed model test on seepage distribution in water diversion tunnel and surrounding fractured rock","authors":"Yajian Shao , Guowei Ma , Wei Zhang","doi":"10.1016/j.tust.2025.106389","DOIUrl":"10.1016/j.tust.2025.106389","url":null,"abstract":"<div><div>Hydro-geomechanical model test is a prevailing method to study the seepage field in the underground engineering. Most of the existing test models are equivalent continuous medium models, whereas the deeply buried diversion tunnel in rock-matrix with fractures in practical engineering exhibit discontinuities, unevenness and heterogeneousness. To this gap, current study constructs an 1800.0 × 1800.0 × 1800.0 mm<sup>3</sup> division tunnel model with fractures in the surrounding rock through 3D additive-subtractive printing, which registers the largest ever 3D printing hydro-geomechanical test model. The current model is based on a practical project of the Jinping II Hydropower Station. The geological strata along the longitudinal direction of the tunnel are surveyed to identify the most critical section in view of instability. Six major cracks in the critical section are identified and measured. According to the scalability principle in the fluid–solid coupling theory, the current model with dimension, density, and permeability scalability coefficients of respective 35, 1, and <span><math><mrow><msqrt><mrow><mn>35</mn></mrow></msqrt></mrow></math></span> to those of the prototype target section is designed and 3D printed. In this 3D printed model, the dip angle and direction of the six major fractures are reproduction of those of the practical fractures, while the locus spacing is reduced by a scale of 35. Structural matrix is additively printed using cement mortar, while fractures are subtractive printed with a customized cutter. The fracture space is filled with a paste medium with variable permeabilities to approach the potential permeability range in the practical fractures. To reproduce the practical hydraulic-mechanical condition in the test, the 3D model is loaded with initial stresses of 150.0 kPa and seepage condition of 20.0 kPa around the model for 7 days prior to the hydraulic loading. To cover the potential practical seepage extent, the external hydraulic pressure is set gradually at five loading levels of 40.0 kPa, 60.0 kPa, 80.0 kPa, 100.0 kPa and 120.0 kPa. The results show that, as the circulating hydraulic pressure increases, the seepage pressure inside the fracture plane and outside the lining structure gradually increases. Test results are in good agreement with the field monitoring data. There is a significant correlation between the seepage pressure in different inclination planes and the distribution characteristics of fractures in its surrounding rock. With denser fractures in the surrounding rock on the lining outside, the seepage pressure in this area will be higher. The test results reflect the discontinuity characteristics of the seepage field inside the fractured rock mass to provide guidance for the stability evaluation and long-term maintenance of water diversion tunnel engineering.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106389"},"PeriodicalIF":6.7,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.tust.2025.106390
Furui Dong , Shuhong Wang , Yong Yang , Mingzhu Ren , Meaza Girma Demisa , Rongzhou Zhang
The factors influencing the stability of the surrounding rock are complex and diverse, characterized by fuzziness and variability. This leads to continuous changes in the stability state of the surrounding rock during tunnel construction, posing a significant threat to construction safety. This paper proposes a dynamic fuzzy prediction method for the stability of surrounding rock throughout the entire construction period of mountain tunnels. Firstly, considering deformation, engineering, and geological factors, a stability evaluation system for the surrounding rock is established, comprising 3 primary indicators and 21 secondary indicators, with the stability state of the surrounding rock classified into five levels. Each evaluation indicator is quantitatively characterized throughout the entire construction period based on the specific of different construction stages. In this process, by defining traction points and traction control equations, an intelligent time-series prediction model for surrounding rock deformation based on traction correction is proposed to accurately obtain surrounding rock deformation indicators. Additionally, a combination weighting method based on the Analytic Hierarchy Process (AHP) and the Entropy Weight Method (EWM) is introduced to calculate the combined weight values of each evaluation indicator at key construction nodes. Simultaneously, a strategy for dynamically adjusting indicator weights is proposed. By defining a weight dynamic adjustment equation, the weights of indicators are smoothly adjusted during different construction periods, achieving real-time updating of indicator weights throughout the entire construction period. The accuracy and reliability of this method are validated through the case study of the Jingang Tunnel, and reasonable suggestions for subsequent construction are provided. This method enables stability prediction and evaluation of surrounding rock throughout the entire construction period, offering a new approach for risk assessment in tunnel construction.
{"title":"Research on dynamic fuzzy prediction method for surrounding rock stability of mountain tunnels throughout the construction period","authors":"Furui Dong , Shuhong Wang , Yong Yang , Mingzhu Ren , Meaza Girma Demisa , Rongzhou Zhang","doi":"10.1016/j.tust.2025.106390","DOIUrl":"10.1016/j.tust.2025.106390","url":null,"abstract":"<div><div>The factors influencing the stability of the surrounding rock are complex and diverse, characterized by fuzziness and variability. This leads to continuous changes in the stability state of the surrounding rock during tunnel construction, posing a significant threat to construction safety. This paper proposes a dynamic fuzzy prediction method for the stability of surrounding rock throughout the entire construction period of mountain tunnels. Firstly, considering deformation, engineering, and geological factors, a stability evaluation system for the surrounding rock is established, comprising 3 primary indicators and 21 secondary indicators, with the stability state of the surrounding rock classified into five levels. Each evaluation indicator is quantitatively characterized throughout the entire construction period based on the specific of different construction stages. In this process, by defining traction points and traction control equations, an intelligent time-series prediction model for surrounding rock deformation based on traction correction is proposed to accurately obtain surrounding rock deformation indicators. Additionally, a combination weighting method based on the Analytic Hierarchy Process (AHP) and the Entropy Weight Method (EWM) is introduced to calculate the combined weight values of each evaluation indicator at key construction nodes. Simultaneously, a strategy for dynamically adjusting indicator weights is proposed. By defining a weight dynamic adjustment equation, the weights of indicators are smoothly adjusted during different construction periods, achieving real-time updating of indicator weights throughout the entire construction period. The accuracy and reliability of this method are validated through the case study of the Jingang Tunnel, and reasonable suggestions for subsequent construction are provided. This method enables stability prediction and evaluation of surrounding rock throughout the entire construction period, offering a new approach for risk assessment in tunnel construction.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106390"},"PeriodicalIF":6.7,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-14DOI: 10.1016/j.tust.2025.106385
Zhe Qin, Wenlong Liu, Fayu Wu, Weiteng Li
The influence of the arching effect on the loosening pressure in shallow tunnels with jointed hard rock is not clear. In order to solve this problem, the analytical model of loosening pressure in shallow tunnels is modified by considering the role of stress deflection and shear resistance under the arching effect of the stratum based on the traditional analytical model of loosening pressure. Relying on the Qingdao Metro Line 6 project, this paper carries out similar model test and numerical simulations, verifies the applicability of the analytical solution, and clarifies the influence of different joint surfaces on the tunnel stability. The results show that: (1) The shallow tunnel stratum arch of jointed hard rock under overlying loads is formed by progressive stepwise evolution. In the limit state, the final arch reduces the surrounding rock pressure acting on the supporting structure, so that the surrounding rock pressure is only 3.8 times of the self-weight of the rock mass in the loosening zone, and the test and numerical results are more in agreement with the analytical solution. (2) In the process of overlying loads, the macro-mechanical properties of the surrounding rock are greatly influenced by the joint surfaces. Preferential cracking of the rock at the arch waist where the joint surfaces are located, with the cracks extending in a figure of eight pattern along the joints. (3) When the joint surfaces tend to be parallel to the direction of the maximum principal stress, the mechanical properties of the rock body are better; with the increase in the number of joint surfaces, the rock body anisotropy is more obvious, and the rock body between the joint surfaces is more fragile and then damage to the detachment. The research results provide a certain reference and guidance for the stability analysis of tunnels with joint surfaces under the timely active support system considering the arching effect.
{"title":"Progressive arching effect and damage evolution process of shallow tunnels with jointed hard rock under overlying loads","authors":"Zhe Qin, Wenlong Liu, Fayu Wu, Weiteng Li","doi":"10.1016/j.tust.2025.106385","DOIUrl":"10.1016/j.tust.2025.106385","url":null,"abstract":"<div><div>The influence of the arching effect on the loosening pressure in shallow tunnels with jointed hard rock is not clear. In order to solve this problem, the analytical model of loosening pressure in shallow tunnels is modified by considering the role of stress deflection and shear resistance under the arching effect of the stratum based on the traditional analytical model of loosening pressure. Relying on the Qingdao Metro Line 6 project, this paper carries out similar model test and numerical simulations, verifies the applicability of the analytical solution, and clarifies the influence of different joint surfaces on the tunnel stability. The results show that: (1) The shallow tunnel stratum arch of jointed hard rock under overlying loads is formed by progressive stepwise evolution. In the limit state, the final arch reduces the surrounding rock pressure acting on the supporting structure, so that the surrounding rock pressure is only 3.8 times of the self-weight of the rock mass in the loosening zone, and the test and numerical results are more in agreement with the analytical solution. (2) In the process of overlying loads, the macro-mechanical properties of the surrounding rock are greatly influenced by the joint surfaces. Preferential cracking of the rock at the arch waist where the joint surfaces are located, with the cracks extending in a figure of eight pattern along the joints. (3) When the joint surfaces tend to be parallel to the direction of the maximum principal stress, the mechanical properties of the rock body are better; with the increase in the number of joint surfaces, the rock body anisotropy is more obvious, and the rock body between the joint surfaces is more fragile and then damage to the detachment. The research results provide a certain reference and guidance for the stability analysis of tunnels with joint surfaces under the timely active support system considering the arching effect.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106385"},"PeriodicalIF":6.7,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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