Pub Date : 2025-01-31DOI: 10.1016/j.tust.2025.106440
Xiaohua Bao , Jiazhi Huang , Jun Shen , Xianlong Wu , Tao Wang , Xiangsheng Chen , Hongzhi Cui
The rebar mesh inside the tunnel lining introduces significant interference in detecting defects, reducing their visibility in GPR images. This study proposes a global-to-local secondary recognition method based on an improved YOLOv8 model to address this challenge. Two datasets—global and local GPR images—were used, with an attention mechanism integrated into the YOLOv8 architecture. The improved YOLOv8 structure has been shown to increase the mean Average Precision (mAP) by 9.36 % and 3.86 % for the two datasets, respectively. Optimal performance was achieved with a rebar spacing of 0.4 m and a secondary recognition confidence of 0.867, while a rebar-defect distance of 1.20 m reached a confidence of 0.858. The model accurately identified the void defect shapes. Compared to traditional rebar signal suppression methods, this approach simplifies data processing, enhances accuracy, and reduces training costs. A tunnel field case further validated the method, boosting GPR image recognition confidence from 0.37 to 0.73, significantly improving the automated detection of tunnel lining defects.
{"title":"A novel method of void detection in rebar-affected areas based on transfer learning and improved YOLOv8","authors":"Xiaohua Bao , Jiazhi Huang , Jun Shen , Xianlong Wu , Tao Wang , Xiangsheng Chen , Hongzhi Cui","doi":"10.1016/j.tust.2025.106440","DOIUrl":"10.1016/j.tust.2025.106440","url":null,"abstract":"<div><div>The rebar mesh inside the tunnel lining introduces significant interference in detecting defects, reducing their visibility in GPR images. This study proposes a global-to-local secondary recognition method based on an improved YOLOv8 model to address this challenge. Two datasets—global and local GPR images—were used, with an attention mechanism integrated into the YOLOv8 architecture. The improved YOLOv8 structure has been shown to increase the mean Average Precision (mAP) by 9.36 % and 3.86 % for the two datasets, respectively. Optimal performance was achieved with a rebar spacing of 0.4 m and a secondary recognition confidence of 0.867, while a rebar-defect distance of 1.20 m reached a confidence of 0.858. The model accurately identified the void defect shapes. Compared to traditional rebar signal suppression methods, this approach simplifies data processing, enhances accuracy, and reduces training costs. A tunnel field case further validated the method, boosting GPR image recognition confidence from 0.37 to 0.73, significantly improving the automated detection of tunnel lining defects.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106440"},"PeriodicalIF":6.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071358","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 : 2025-01-30DOI: 10.1016/j.tust.2025.106433
Xieping Huang, Yansong Yue, Bin Zhu, Yunmin Chen
The underground concrete silo, designed as a hollow cylinder with a large aspect ratio and thin walls, is highly susceptible to failure caused by intentional or accidental soil explosions. To enhance its protection, this study investigates the dynamic tensile responses and failure mechanisms of underground concrete silos subjected to high-yield soil explosions. The concept of nominal crack width is proposed to quantitatively describe the degree of overall bending-induced tensile responses and failure of the concrete silo. The influences of explosive weights, standoff distances, and the aspect ratios and thicknesses of the underground concrete silo are quantitatively explored first. On this basis, a dimensionless number combining these major influencing factors is derived using dimensional analysis. The derived dimensionless number has a clear physical meaning, reflecting three aspects: the inertia of the blast loading, the resistance ability of concrete material to bending responses and failure, and the resistance ability of silo structure to bending responses and failure. The results demonstrate that the proposed dimensionless number effectively correlates with the overall bending-induced tensile responses and failure of silo structures across various geometries and explosion scenarios, exhibiting a good linear relation with the dimensionless nominal crack width of the concrete silo. With its solid physical foundation, the dimensionless number offers practical applications in scaling analysis and fast damage assessment. Specific examples of these applications are presented and discussed in this study.
{"title":"Suggestion of a dimensionless number for dynamic tensile responses and failure of underground concrete silos subjected to soil explosions","authors":"Xieping Huang, Yansong Yue, Bin Zhu, Yunmin Chen","doi":"10.1016/j.tust.2025.106433","DOIUrl":"10.1016/j.tust.2025.106433","url":null,"abstract":"<div><div>The underground concrete silo, designed as a hollow cylinder with a large aspect ratio and thin walls, is highly susceptible to failure caused by intentional or accidental soil explosions. To enhance its protection, this study investigates the dynamic tensile responses and failure mechanisms of underground concrete silos subjected to high-yield soil explosions. The concept of nominal crack width is proposed to quantitatively describe the degree of overall bending-induced tensile responses and failure of the concrete silo. The influences of explosive weights, standoff distances, and the aspect ratios and thicknesses of the underground concrete silo are quantitatively explored first. On this basis, a dimensionless number combining these major influencing factors is derived using dimensional analysis. The derived dimensionless number has a clear physical meaning, reflecting three aspects: the inertia of the blast loading, the resistance ability of concrete material to bending responses and failure, and the resistance ability of silo structure to bending responses and failure. The results demonstrate that the proposed dimensionless number effectively correlates with the overall bending-induced tensile responses and failure of silo structures across various geometries and explosion scenarios, exhibiting a good linear relation with the dimensionless nominal crack width of the concrete silo. With its solid physical foundation, the dimensionless number offers practical applications in scaling analysis and fast damage assessment. Specific examples of these applications are presented and discussed in this study.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106433"},"PeriodicalIF":6.7,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071415","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 : 2025-01-30DOI: 10.1016/j.tust.2025.106429
Zhi Zheng , Ronghua Li , Pengzhi Pan , Wei Wang
The current research on the failure theory of surrounding rock failure caused by excavation disturbance of deep buried engineering is seriously insufficient, especially under the combined conditions of true three-dimensional stress and excavation disturbance, which leads to unclear excavation responses and engineering disasters. Therefore, this study carried out true triaxial disturbance tests to investigate the mechanical characteristics of rock under excavation unloading and disturbance in deep engineering. Calculation methods for the anisotropic Young’s modulus, cohesion, friction angle and dilation angle during rock fracture were proposed to reveal their evolutions. A dynamic anisotropic mechanical model reflecting rock degradation induced by true triaxial disturbance was further established, and the numerical program was implemented in finite difference software. Numerical simulation results with proposed model were basically consistent with laboratory tests and deep engineering field monitoring data. Based on numerical simulation, a rock disturbance fracture degree index was proposed to quantitatively evaluate the fracture location, range and failure degree of surrounding rock after engineering excavation disturbance. Compared with static excavation, disturbance excavation leads to larger deformation of surrounding rock, larger depth and degree of failure, and more energy released.
{"title":"Excavation disturbance response of deep-buried tunnel with novel dynamic anisotropic mechanical model and failure degree index","authors":"Zhi Zheng , Ronghua Li , Pengzhi Pan , Wei Wang","doi":"10.1016/j.tust.2025.106429","DOIUrl":"10.1016/j.tust.2025.106429","url":null,"abstract":"<div><div>The current research on the failure theory of surrounding rock failure caused by excavation disturbance of deep buried engineering is seriously insufficient, especially under the combined conditions of true three-dimensional stress and excavation disturbance, which leads to unclear excavation responses and engineering disasters. Therefore, this study carried out true triaxial disturbance tests to investigate the mechanical characteristics of rock under excavation unloading and disturbance in deep engineering. Calculation methods for the anisotropic Young’s modulus, cohesion, friction angle and dilation angle during rock fracture were proposed to reveal their evolutions. A dynamic anisotropic mechanical model reflecting rock degradation induced by true triaxial disturbance was further established, and the numerical program was implemented in finite difference software. Numerical simulation results with proposed model were basically consistent with laboratory tests and deep engineering field monitoring data. Based on numerical simulation, a rock disturbance fracture degree index was proposed to quantitatively evaluate the fracture location, range and failure degree of surrounding rock after engineering excavation disturbance. Compared with static excavation, disturbance excavation leads to larger deformation of surrounding rock, larger depth and degree of failure, and more energy released.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106429"},"PeriodicalIF":6.7,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071416","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 : 2025-01-29DOI: 10.1016/j.tust.2025.106434
Jiangrong Hou , Yuanming Lai , Xiaoxiao Luo , Wenqiang Jiang , Haiyong Chen , Qinguo Ma
Over 50 % of tunnels in cold regions of China suffer from frost damage, significantly affecting their normal operation. Laying insulation layer is a primary measure for preventing frost damage of tunnels. However, due to improper laying length of insulation layer, many tunnels with insulation layer still suffer from frost damage. It is a challenge to accurately determine the tunnel freezing length and laying length of insulation layer. Focusing on the Yushuchuan tunnel on the Jilin-Tumen-Hunchun Passenger Dedicated Line as the research object, the temperature distribution, freezing length, and laying length of insulation layer of the tunnel under the action of natural wind are analyzed by field monitoring, numerical simulation and theoretical calculation. The results show that: (1) Ambient temperature primarily affects the temperature distribution of the tunnel at the entrance section. The freezing lengths at the tunnel entrance under the wind speeds of 1, 2, 4, 5.44 and 6 m/s are 303, 743, 1044, 1462 and 1581 m, respectively, while the freezing length at the exit section varies within the range of 21 to 37 m. The entrance section is the critical area for frost damage. (2) After laying the insulation layer, cold air can penetrate into the deeper position of the tunnel, and the laying length of insulation layer should be longer than the tunnel freezing length, with the values of 400, 990, 1370, 1900 and 2060 m, respectively under the wind speeds of 1, 2, 4, 5.44 and 6 m/s. (3) Considering the tunnel size, surrounding rock temperature, lining thickness and meteorological conditions at the tunnel site, the theoretical formulas for the tunnel freezing length and laying length of insulation layer are proposed and verified through a large amount of survey data on frost damage of tunnels in cold regions.
{"title":"Temperature distribution and calculation methods for freezing length and laying length of insulation layer of a tunnel in cold regions","authors":"Jiangrong Hou , Yuanming Lai , Xiaoxiao Luo , Wenqiang Jiang , Haiyong Chen , Qinguo Ma","doi":"10.1016/j.tust.2025.106434","DOIUrl":"10.1016/j.tust.2025.106434","url":null,"abstract":"<div><div>Over 50 % of tunnels in cold regions of China suffer from frost damage, significantly affecting their normal operation. Laying insulation layer is a primary measure for preventing frost damage of tunnels. However, due to improper laying length of insulation layer, many tunnels with insulation layer still suffer from frost damage. It is a challenge to accurately determine the tunnel freezing length and laying length of insulation layer. Focusing on the Yushuchuan tunnel on the Jilin-Tumen-Hunchun Passenger Dedicated Line as the research object, the temperature distribution, freezing length, and laying length of insulation layer of the tunnel under the action of natural wind are analyzed by field monitoring, numerical simulation and theoretical calculation. The results show that: (1) Ambient temperature primarily affects the temperature distribution of the tunnel at the entrance section. The freezing lengths at the tunnel entrance under the wind speeds of 1, 2, 4, 5.44 and 6 m/s are 303, 743, 1044, 1462 and 1581 m, respectively, while the freezing length at the exit section varies within the range of 21 to 37 m. The entrance section is the critical area for frost damage. (2) After laying the insulation layer, cold air can penetrate into the deeper position of the tunnel, and the laying length of insulation layer should be longer than the tunnel freezing length, with the values of 400, 990, 1370, 1900 and 2060 m, respectively under the wind speeds of 1, 2, 4, 5.44 and 6 m/s. (3) Considering the tunnel size, surrounding rock temperature, lining thickness and meteorological conditions at the tunnel site, the theoretical formulas for the tunnel freezing length and laying length of insulation layer are proposed and verified through a large amount of survey data on frost damage of tunnels in cold regions.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106434"},"PeriodicalIF":6.7,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071420","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 : 2025-01-27DOI: 10.1016/j.tust.2025.106406
Wanpeng Shi , Danqing Song , Xiaoli Liu
The dynamic response of slope-tunnel systems under seismic loading is complex due to the intricate interaction between the slope, tunnel, and earthquake. This work investigates these dynamics characteristics through frequency-domain analysis, focusing on key parameters including peak Fourier spectrum amplitude (PFSA), the ratio of horizontal to vertical Fourier spectral (FSR), and acceleration amplification coefficient. The shaking table tests reveal that the seismic intensity and frequency significantly influences the dynamic response and spectral characteristics of the slope. As seismic intensity increases, the inherent frequencies, MPGA, and FSR within the slope gradually decrease, while PFSA increases. Low-frequency components (0–30 Hz) primarily cause overall deformation beneath the tunnel and inside the slope, while high-frequency components (48–70 Hz) mainly induce shear band deformation on the slope surface. Additionally, this work investigated the impact of seismic waves in different directions on the spectral transformation and damage deformation of the slope-tunnel system. Vertical seismic waves mainly affect settlement deformation and crack propagation in weak interlayers and tunnel. Meantime, the vertical waves amplify the high-frequency band in the Fourier spectrum of horizontal seismic waves. Moreover, the correlation between the inherent frequencies of the slope-tunnel system and MPGA is further evaluated via Pearson correlation coefficients. The cumulative damage factors of the slope following an exponential trend. The frequency-domain analysis conducted accurately represents the seismic response characteristics of slope-tunnel systems, thereby facilitating enhanced seismic performance and structural safety of engineering designs.
{"title":"Dynamic response characteristics and damage evolution process of a slope-tunnel system containing parallel traversing weak interlayers based on frequency domain analysis via shaking table test","authors":"Wanpeng Shi , Danqing Song , Xiaoli Liu","doi":"10.1016/j.tust.2025.106406","DOIUrl":"10.1016/j.tust.2025.106406","url":null,"abstract":"<div><div>The dynamic response of slope-tunnel systems under seismic loading is complex due to the intricate interaction between the slope, tunnel, and earthquake. This work investigates these dynamics characteristics through frequency-domain analysis, focusing on key parameters including peak Fourier spectrum amplitude (PFSA), the ratio of horizontal to vertical Fourier spectral (FSR), and acceleration amplification coefficient. The shaking table tests reveal that the seismic intensity and frequency significantly influences the dynamic response and spectral characteristics of the slope. As seismic intensity increases, the inherent frequencies, M<sub>PGA</sub>, and FSR within the slope gradually decrease, while PFSA increases. Low-frequency components (0–30 Hz) primarily cause overall deformation beneath the tunnel and inside the slope, while high-frequency components (48–70 Hz) mainly induce shear band deformation on the slope surface. Additionally, this work investigated the impact of seismic waves in different directions on the spectral transformation and damage deformation of the slope-tunnel system. Vertical seismic waves mainly affect settlement deformation and crack propagation in weak interlayers and tunnel. Meantime, the vertical waves amplify the high-frequency band in the Fourier spectrum of horizontal seismic waves. Moreover, the correlation between the inherent frequencies of the slope-tunnel system and M<sub>PGA</sub> is further evaluated via Pearson correlation coefficients. The cumulative damage factors of the slope following an exponential trend. The frequency-domain analysis conducted accurately represents the seismic response characteristics of slope-tunnel systems, thereby facilitating enhanced seismic performance and structural safety of engineering designs.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106406"},"PeriodicalIF":6.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071467","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 : 2025-01-27DOI: 10.1016/j.tust.2025.106426
Jinfeng Xu , Hehua Zhu , Wuqiang Cai , Kui Wu , Anmin Wang , Cheng Lyu
Deep tunnel excavation in squeezing rock has strong tendency to asymmetric large deformation under the influence of active fracture zones. Issues, including steel arch twisting, shotcrete cracking and spalling and anchor failure could lead to the damage of the primary support and compression collapse in the reinforced concrete of the secondary lining. In order to explore the mechanism of asymmetric large deformation and control its potential threats, the research team has carried out a series of in-situ tests, including ground stress test, rock sample composition analysis, rock structure surface identification, high-density electrical resistance method test, and surrounding rock loosening zone test in the excavation surface on the Daliangshan Tunnel of Yunlin Highway in Yunnan Province. The research findings show that the geologic tectonics and volcanism could cause an intrusion of the granite into the schist to form the mechanical genesis mechanism of the extruded tectonic stress and lithologic contact zone. According to the yielding principle and the New Austrian Tunnelling Method, the research team has raised a two-scheme proposal for controlling the extrusion deformation of the tunnel based on a comparative study on the two schemes. The results show that the yielding support control scheme could have positive impact on the control of asymmetric large deformation section and the stress distribution of the tunnel surrounding rock. After the adoption of yielding support control method, the stress state of surrounding rock showed reasonable improvement by 32.5% less in the degree of its unevenness at its the largest bearing capacity. This support scheme has also cut down the costs of tunnel support by 10% compared to double-layer rigid primary support scheme. The research method has already been applied to the construction of large deformation section in the Daliangshan tunnel and the nearby Tianshengqiao tunnel.
{"title":"Failure mechanism analysis and yielding support control method for asymmetric large deformation tunnels in squeezing rock: A case study","authors":"Jinfeng Xu , Hehua Zhu , Wuqiang Cai , Kui Wu , Anmin Wang , Cheng Lyu","doi":"10.1016/j.tust.2025.106426","DOIUrl":"10.1016/j.tust.2025.106426","url":null,"abstract":"<div><div>Deep tunnel excavation in squeezing rock has strong tendency to asymmetric large deformation under the influence of active fracture zones. Issues, including steel arch twisting, shotcrete cracking and spalling and anchor failure could lead to the damage of the primary support and compression collapse in the reinforced concrete of the secondary lining. In order to explore the mechanism of asymmetric large deformation and control its potential threats, the research team has carried out a series of in-situ tests, including ground stress test, rock sample composition analysis, rock structure surface identification, high-density electrical resistance method test, and surrounding rock loosening zone test in the excavation surface on the Daliangshan Tunnel of Yunlin Highway in Yunnan Province. The research findings show that the geologic tectonics and volcanism could cause an intrusion of the granite into the schist to form the mechanical genesis mechanism of the extruded tectonic stress and lithologic contact zone. According to the yielding principle and the New Austrian Tunnelling Method, the research team has raised a two-scheme proposal for controlling the extrusion deformation of the tunnel based on a comparative study on the two schemes. The results show that the yielding support control scheme could have positive impact on the control of asymmetric large deformation section and the stress distribution of the tunnel surrounding rock. After the adoption of yielding support control method, the stress state of surrounding rock showed reasonable improvement by 32.5% less in the degree of its unevenness at its the largest bearing capacity. This support scheme has also cut down the costs of tunnel support by 10% compared to double-layer rigid primary support scheme. The research method has already been applied to the construction of large deformation section in the Daliangshan tunnel and the nearby Tianshengqiao tunnel.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106426"},"PeriodicalIF":6.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071466","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 : 2025-01-25DOI: 10.1016/j.tust.2025.106422
Zhifu Shen , Yixin Zhao , Yang Lv , Panpan Wang , Nan Hu , Fangzhi Shu , Hongmei Gao , Zhihua Wang
Water-sand inrush is one of the most destructive disasters for underground structures buried in saturated erodible soils. The related upward propagation of ground disturbance has not been well understood so far. In this study, a series of numerical simulations were performed to investigate such disturbance propagation behavior. Typical dual-stratum geological condition was modeled since this was the most common condition where water–sand inrush disasters had been widely reported previously. The numerical simulations applied discrete particles to model the lower sand layer, continuum mechanics to model the overlying clay layer, and Darcy’s law to model the underground water flow, with solid–fluid coupling considered. The simulation results were reported and were compared with available data from the literature. It was found that the sand and water loss rates were highly dependent on location of the inrush opening, which was attributed to the different local porosity near the opening, a result of the particle-scale fluid–solid coupling. A funnel-type sand flowing pattern can be identified, and the upward propagation of ground disturbance can be described by evolution of a loosening ellipse that outlines the extent of ground experiencing displacement. As the water–sand inrush proceeded, the tendency of vertical alignment of the loosening ellipse suggests an increasing role of gravity relative to the fluid–solid coupling force in driving particle motion. The ground disturbance propagation was accompanied with localization in strain rate, dissipative work, and particle spin rate. The non-uniform ground displacement was accompanied with re-distribution of stress in the form of continuously evolving soil arches. The cross-stratum soil arch can lead to unloading process at the stratum interface and consequently cause upper payer instability.
{"title":"Upward propagation of ground disturbance induced by water–sand inrush into a defective tunnel in a dual-stratum geological condition","authors":"Zhifu Shen , Yixin Zhao , Yang Lv , Panpan Wang , Nan Hu , Fangzhi Shu , Hongmei Gao , Zhihua Wang","doi":"10.1016/j.tust.2025.106422","DOIUrl":"10.1016/j.tust.2025.106422","url":null,"abstract":"<div><div>Water-sand inrush is one of the most destructive disasters for underground structures buried in saturated erodible soils. The related upward propagation of ground disturbance has not been well understood so far. In this study, a series of numerical simulations were performed to investigate such disturbance propagation behavior. Typical dual-stratum geological condition was modeled since this was the most common condition where water–sand inrush disasters had been widely reported previously. The numerical simulations applied discrete particles to model the lower sand layer, continuum mechanics to model the overlying clay layer, and Darcy’s law to model the underground water flow, with solid–fluid coupling considered. The simulation results were reported and were compared with available data from the literature. It was found that the sand and water loss rates were highly dependent on location of the inrush opening, which was attributed to the different local porosity near the opening, a result of the particle-scale fluid–solid coupling. A funnel-type sand flowing pattern can be identified, and the upward propagation of ground disturbance can be described by evolution of a loosening ellipse that outlines the extent of ground experiencing displacement. As the water–sand inrush proceeded, the tendency of vertical alignment of the loosening ellipse suggests an increasing role of gravity relative to the fluid–solid coupling force in driving particle motion. The ground disturbance propagation was accompanied with localization in strain rate, dissipative work, and particle spin rate. The non-uniform ground displacement was accompanied with re-distribution of stress in the form of continuously evolving soil arches. The cross-stratum soil arch can lead to unloading process at the stratum interface and consequently cause upper payer instability.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106422"},"PeriodicalIF":6.7,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071470","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 : 2025-01-25DOI: 10.1016/j.tust.2025.106423
Meixia Wang , Shijie Ma , Zongqing Zhou , Weimin Yang , Songsong Bai , Yifan Bai
Mud and water bursts within fault fracture zone frequently lead to casualties, equipment damage, and project delays, posing significant risks. A thorough scientific understanding of these mechanisms is essential for effective disaster prevention and control. To investigate the evolution mechanisms of mud and water burst in fault fracture zones, an experimental apparatus was designed to simulate the migration and loss of filling material particles under triaxial loading conditions. Experiments conducted with this apparatus explored the evolution process of mud and water bursts under varying initial dry densities. The results demonstrate that the evolution of mud and water bursts is a complex process, characterized by increased porosity and permeability, decreased strength, and fluctuating viscosity. The initial dry density plays a critical role in determining the failure mode of mud and water bursts. At low initial dry densities, the filling material is prone to seepage failure. In contrast, at high initial dry densities and elevated water pressures, the material is more likely to experience splitting failure. In comparison to seepage failure, the evolution process of splitting failure exhibits a significant delay, with a longer incubation period. However, it can rapidly form seepage channels in a short time, leading to more severe mud and water bursts. Finally, the study analyzed variations in porosity, permeability, and shear strength associated with different failure modes. Generalized models were established to describe the evolutionary characteristics of both seepage and splitting failure. These findings offer valuable insights for improving the safety and stability of tunnel engineering in environments prone to such risks.
{"title":"Impact of initial dry density on the evolution mechanism of mud and water burst in fault fracture zones: A series of experimental studies","authors":"Meixia Wang , Shijie Ma , Zongqing Zhou , Weimin Yang , Songsong Bai , Yifan Bai","doi":"10.1016/j.tust.2025.106423","DOIUrl":"10.1016/j.tust.2025.106423","url":null,"abstract":"<div><div>Mud and water bursts within fault fracture zone frequently lead to casualties, equipment damage, and project delays, posing significant risks. A thorough scientific understanding of these mechanisms is essential for effective disaster prevention and control. To investigate the evolution mechanisms of mud and water burst in fault fracture zones, an experimental apparatus was designed to simulate the migration and loss of filling material particles under triaxial loading conditions. Experiments conducted with this apparatus explored the evolution process of mud and water bursts under varying initial dry densities. The results demonstrate that the evolution of mud and water bursts is a complex process, characterized by increased porosity and permeability, decreased strength, and fluctuating viscosity. The initial dry density plays a critical role in determining the failure mode of mud and water bursts. At low initial dry densities, the filling material is prone to seepage failure. In contrast, at high initial dry densities and elevated water pressures, the material is more likely to experience splitting failure. In comparison to seepage failure, the evolution process of splitting failure exhibits a significant delay, with a longer incubation period. However, it can rapidly form seepage channels in a short time, leading to more severe mud and water bursts. Finally, the study analyzed variations in porosity, permeability, and shear strength associated with different failure modes. Generalized models were established to describe the evolutionary characteristics of both seepage and splitting failure. These findings offer valuable insights for improving the safety and stability of tunnel engineering in environments prone to such risks.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106423"},"PeriodicalIF":6.7,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071469","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 : 2025-01-25DOI: 10.1016/j.tust.2025.106421
Xiangsheng Chen , Qiufeng He , Jinshan Qiu , Lei Wang , Dong Su , Meilin Liu , Kunyang Chen , Tong Qiu
The increasing urban building density has driven the utilisation of underground space for constructing urban municipal infrastructure and transportation systems, alleviating land scarcity. However, the construction of underground projects within densely populated cities poses challenges such as traffic congestion, secondary excavations, and settlement of adjacent building foundations. Accordingly, the simultaneous construction of subways and utility tunnels (SCSUT) has emerged as a practical solution for developing underground spaces in high-density areas. By integrating the constructions of urban rail transit and municipal infrastructure from a long-term perspective, SCSUT could reduce road occupancy and minimize impacts on existing structures. Despite its advantages, SCSUT implementation remains challenging, with few practical cases available. To gain insight into the SCSUT, this study first examines its necessity and global implementation status. Meanwhile, this research identifies the existing implementation strategies of the SCSUT in terms of construction management, pipeline layout, and typical construction schemes. Furthermore, an in-depth analysis of the largest existing SCSUT project is conducted. Findings indicate that the SCSUT, currently in its early development stage, faces several critical challenges, including the lack of technical standards, complex approval processes and management models, inadequate geological surveys and preliminary planning, and frequent design changes. To realize the significant potential benefits of the SCSUT, future efforts should focus on developing technical standards based on relevant engineering cases, enhancing early-stage planning, and leveraging digital technologies to support construction. This study is anticipated to be a valuable reference for policy improvement and other SCSUT projects similar to the case study.
{"title":"Simultaneous construction of subways and utility tunnels: A case project in Shenzhen, China","authors":"Xiangsheng Chen , Qiufeng He , Jinshan Qiu , Lei Wang , Dong Su , Meilin Liu , Kunyang Chen , Tong Qiu","doi":"10.1016/j.tust.2025.106421","DOIUrl":"10.1016/j.tust.2025.106421","url":null,"abstract":"<div><div>The increasing urban building density has driven the utilisation of underground space for constructing urban municipal infrastructure and transportation systems, alleviating land scarcity. However, the construction of underground projects within densely populated cities poses challenges such as traffic congestion, secondary excavations, and settlement of adjacent building foundations. Accordingly, the simultaneous construction of subways and utility tunnels (SCSUT) has emerged as a practical solution for developing underground spaces in high-density areas. By integrating the constructions of urban rail transit and municipal infrastructure from a long-term perspective, SCSUT could reduce road occupancy and minimize impacts on existing structures. Despite its advantages, SCSUT implementation remains challenging, with few practical cases available. To gain insight into the SCSUT, this study first examines its necessity and global implementation status. Meanwhile, this research identifies the existing implementation strategies of the SCSUT in terms of construction management, pipeline layout, and typical construction schemes. Furthermore, an in-depth analysis of the largest existing SCSUT project is conducted. Findings indicate that the SCSUT, currently in its early development stage, faces several critical challenges, including the lack of technical standards, complex approval processes and management models, inadequate geological surveys and preliminary planning, and frequent design changes. To realize the significant potential benefits of the SCSUT, future efforts should focus on developing technical standards based on relevant engineering cases, enhancing early-stage planning, and leveraging digital technologies to support construction. This study is anticipated to be a valuable reference for policy improvement and other SCSUT projects similar to the case study.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106421"},"PeriodicalIF":6.7,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072067","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 : 2025-01-24DOI: 10.1016/j.tust.2025.106401
Zehao Ye , Wei Lin , Asaad Faramarzi , Xiongyao Xie , Jelena Ninić
Asset management ensures the safety and longevity of structures through regular maintenance. Reality capture technologies are increasingly being used for asset inspections to obtain information by generating point cloud data, which is becoming more prevalent in tunnel asset management for precise documentation of tunnel geometry and condition. Integrating semantic information from point clouds is crucial for creating accurate as-built Building Information Models (BIM), essential for project delivery, maintenance, and operations. In this paper, we propose SAM4Tun, a zero-shot automated instance segmentation method for tunnel lining segments. It is based on a Large Vision Model (LVM), prompt-based Segment Anything Model (SAM), and various point cloud and image processing techniques, enabling accurate instance segmentation without requiring any training. The process starts by unfolding tunnel point clouds to generate 2D panoramic images, enabling SAM to be extend its capabilities to point cloud segmentation. To enhance performance, we propose: (i) a local point cloud density-variation method to filter out non-segment parts, and (ii) a geometry feature-guided multi-step point cloud up-sampling method to address uneven point cloud density during projection. Then, we focus on prompt engineering, using traditional image processing techniques to automatically generate template prompt, enabling SAM’s zero-shot ability to achieve precise instance-level segmentation of tunnel linings. The results demonstrate that our no-training model achieved highly accurate instance segmentation, even surpassing supervised learning algorithms. The proposed method addresses the issue of data dependency and serves as the foundation for component-level damage localization and displacement monitoring in tunnel. Our code is available at https://github.com/zxy239/SAM4Tun.
{"title":"SAM4Tun: No-training model for tunnel lining point cloud component segmentation","authors":"Zehao Ye , Wei Lin , Asaad Faramarzi , Xiongyao Xie , Jelena Ninić","doi":"10.1016/j.tust.2025.106401","DOIUrl":"10.1016/j.tust.2025.106401","url":null,"abstract":"<div><div>Asset management ensures the safety and longevity of structures through regular maintenance. Reality capture technologies are increasingly being used for asset inspections to obtain information by generating point cloud data, which is becoming more prevalent in tunnel asset management for precise documentation of tunnel geometry and condition. Integrating semantic information from point clouds is crucial for creating accurate as-built Building Information Models (BIM), essential for project delivery, maintenance, and operations. In this paper, we propose SAM4Tun, a zero-shot automated instance segmentation method for tunnel lining segments. It is based on a Large Vision Model (LVM), prompt-based Segment Anything Model (SAM), and various point cloud and image processing techniques, enabling accurate instance segmentation without requiring any training. The process starts by unfolding tunnel point clouds to generate 2D panoramic images, enabling SAM to be extend its capabilities to point cloud segmentation. To enhance performance, we propose: (i) a local point cloud density-variation method to filter out non-segment parts, and (ii) a geometry feature-guided multi-step point cloud up-sampling method to address uneven point cloud density during projection. Then, we focus on prompt engineering, using traditional image processing techniques to automatically generate template prompt, enabling SAM’s zero-shot ability to achieve precise instance-level segmentation of tunnel linings. The results demonstrate that our no-training model achieved highly accurate instance segmentation, even surpassing supervised learning algorithms. The proposed method addresses the issue of data dependency and serves as the foundation for component-level damage localization and displacement monitoring in tunnel. Our code is available at <span><span>https://github.com/zxy239/SAM4Tun</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106401"},"PeriodicalIF":6.7,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027394","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}
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