Assessment of tunnel lining resilience is critical to ensure long-term structural stability under soft rock excavation. In this paper, a novel analytical approach is proposed to assess its performance, considering the time-dependent properties of tunnel deformation. Based on the complex stress behavior of lining, the ratio of compressive and tensile stress to its strength is selected as a performance indicator (Q) of resilience. A new resilience metric (Re) is defined to explore the non-uniform stress behavior of the lining. This metric is calculated as the ratio of the integral of disturbed Q to that of undisturbed Q by incorporating the spatial parameters of the lining. Subsequently, the rationality and applicability of the proposed method are validated through a case study involving a diversion tunnel exhibiting time-dependent deformation behavior. The parameters of compressible layer support are optimized based on Re. The results indicate that the lining Re decreases substantially (Re < 0.6) within three years and stabilizes at 0.34 after 50 years. The analysis of lining Q behavior reveals that the arch foot and invert experience more substantial reductions in Q during operation. The incorporation of compressible layers as support enhances the sustained resilience of the lining once a critical threshold is reached, maintaining Re at an approximately constant level over time. This improvement depends on the energy absorption capacity and utilization efficiency of compressible layers.
{"title":"Resilience analysis of tunnel lining under creep-induced convergence of soft rock: Characterization and field application","authors":"Xiaoyun Shu , Weizhong Chen , Hongming Tian , Zhende Zhu , Jingqiang Yuan , Jianxin Yu","doi":"10.1016/j.tust.2025.106691","DOIUrl":"10.1016/j.tust.2025.106691","url":null,"abstract":"<div><div>Assessment of tunnel lining resilience is critical to ensure long-term structural stability under soft rock excavation. In this paper, a novel analytical approach is proposed to assess its performance, considering the time-dependent properties of tunnel deformation. Based on the complex stress behavior of lining, the ratio of compressive and tensile stress to its strength is selected as a performance indicator (<em>Q</em>) of resilience. A new resilience metric (Re) is defined to explore the non-uniform stress behavior of the lining. This metric is calculated as the ratio of the integral of disturbed <em>Q</em> to that of undisturbed <em>Q</em> by incorporating the spatial parameters of the lining. Subsequently, the rationality and applicability of the proposed method are validated through a case study involving a diversion tunnel exhibiting time-dependent deformation behavior. The parameters of compressible layer support are optimized based on Re. The results indicate that the lining Re decreases substantially (Re < 0.6) within three years and stabilizes at 0.34 after 50 years. The analysis of lining <em>Q</em> behavior reveals that the arch foot and invert experience more substantial reductions in <em>Q</em> during operation. The incorporation of compressible layers as support enhances the sustained resilience of the lining once a critical threshold is reached, maintaining Re at an approximately constant level over time. This improvement depends on the energy absorption capacity and utilization efficiency of compressible layers.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106691"},"PeriodicalIF":6.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868655","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}
Tunnel fire is one of the major challenges that cannot be ignored in the safe operation of tunnels. Considering the structure characteristics and bigger heat release rates of tunnel fires, multi-point centralized smoke exhaust coupling with longitudinal ventilation mode is practical in tunnel engineering project, which is significantly important to study the ceiling longitudinal temperature decay and heat exhaust efficiency of such tunnels. Experimental tests are conducted. The experimental variables include heat release rate, number of smoke vents and smoke exhaust volume, while maintaining the longitudinal wind speed at the critical velocity during the experiment. The results show that the tunnel ceiling smoke temperature significantly decreases after passing through the smoke exhaust vent, and the temperature decreases rapidly with the increase of smoke exhaust volume. When there are multiple smoke exhaust vents, the tunnel ceiling temperature between the smoke exhaust vents shows a significant segmented decay trend. The sudden decrease in temperature caused by smoke exhaust only affects the overall change in ceiling temperature and does not affect the decay trend of ceiling temperature. The empirical coefficient was proposed to characterize the reduction effect of smoke exhaust on the ceiling longitudinal temperature, the smoke exhaust efficiency was calculated. The correlation between empirical coefficient , heat exhaust efficiency , dimensionless smoke exhaust volume , and dimensionless heat release rate was proposed. The correlation between the longitudinal profile difference of CO concentration and smoke temperature and smoke exhaust volume was obtained. The correlation between coefficient and heat exhaust efficiency has been verified. The research results can provide support for tunnel fire safety and tunnel fire hazard rescue.
{"title":"Temperature decay and heat exhaust efficiency under ceiling multi-point centralized smoke exhaust in a ventilated tunnel","authors":"Peng Hu , Maohua Zhong , Huihang Cheng , Junfeng Chen , Peihong Zhang","doi":"10.1016/j.tust.2025.106658","DOIUrl":"10.1016/j.tust.2025.106658","url":null,"abstract":"<div><div>Tunnel fire is one of the major challenges that cannot be ignored in the safe operation of tunnels. Considering the structure characteristics and bigger heat release rates of tunnel fires, multi-point centralized smoke exhaust coupling with longitudinal ventilation mode is practical in tunnel engineering project, which is significantly important to study the ceiling longitudinal temperature decay and heat exhaust efficiency of such tunnels. Experimental tests are conducted. The experimental variables include heat release rate, number of smoke vents and smoke exhaust volume, while maintaining the longitudinal wind speed at the critical velocity during the experiment. The results show that the tunnel ceiling smoke temperature significantly decreases after passing through the smoke exhaust vent, and the temperature decreases rapidly with the increase of smoke exhaust volume. When there are multiple smoke exhaust vents, the tunnel ceiling temperature between the smoke exhaust vents shows a significant segmented decay trend. The sudden decrease in temperature caused by smoke exhaust only affects the overall change in ceiling temperature and does not affect the decay trend of ceiling temperature. The empirical coefficient <span><math><mrow><mi>β</mi></mrow></math></span> was proposed to characterize the reduction effect of smoke exhaust on the ceiling longitudinal temperature, the smoke exhaust efficiency <span><math><mrow><mi>E</mi></mrow></math></span> was calculated. The correlation between empirical coefficient <span><math><mrow><mi>β</mi></mrow></math></span>, heat exhaust efficiency <span><math><mrow><mi>E</mi></mrow></math></span>, dimensionless smoke exhaust volume <span><math><mrow><msup><mrow><mi>V</mi></mrow><mrow><mo>∗</mo></mrow></msup></mrow></math></span>, and dimensionless heat release rate <span><math><mrow><msup><mrow><mi>Q</mi></mrow><mrow><mo>∗</mo></mrow></msup></mrow></math></span> was proposed. The correlation between the longitudinal profile difference of CO concentration and smoke temperature and smoke exhaust volume was obtained. The correlation between coefficient <span><math><mrow><mi>β</mi></mrow></math></span> and heat exhaust efficiency has been verified. The research results can provide support for tunnel fire safety and tunnel fire hazard rescue.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106658"},"PeriodicalIF":6.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868654","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 : 2025-04-25DOI: 10.1016/j.tust.2025.106653
Shaohui Du , Yifan Zhang , Lianzhi Yang , Fanmin He , Tao Peng
The determination of discharge and hydraulic head of underground caverns is a crucial aspect for their engineering construction. The boundary of aquifer should be bounded for the calculation of seepage field of underground caverns in coastal areas. Therefore, analytical solutions for discharge and hydraulic head of underground caverns with square arch cross-section in a three-dimensional(3D) bounded unconfined aquifer are presented in this paper. Fourier series expansion and Laplace transform are used to obtain a point sink solution. Solutions of discharge and hydraulic head caused by multiple caverns with square arch cross-section in the 3D bounded unconfined aquifer are obtained by integrating the point sink solution in cavern domain which includes cavern cavity, cavern surface and cavern outline (C-S-O integration method). The accuracy of the point sink solution and the cuboid cavern solution is verified by comparing with numerical solutions obtained by COMSOL. The comparison shows that the analytical solutions agree well with numerical solutions. The effects of vertical hydraulic conductivity and specific yield on cavern discharge and hydraulic head are investigated. Treatment methods for actual projects which usually involve the construction of multiple caverns with square arch cross-section, and the long axis of the cavern forms an angle θ with the horizontal axis are presented. A more simplified integration method (S-O), which includes only cavern surface and cavern outline, is proposed, and compared with the results of C-S-O, which indicates that the simplified approach achieves comparable accuracy. The study offers theoretical reference for the prediction of discharge and groundwater level during the excavation and operation of underground caverns.
{"title":"Analytical solutions for discharge and hydraulic head of three-dimensional underground caverns in coastal areas","authors":"Shaohui Du , Yifan Zhang , Lianzhi Yang , Fanmin He , Tao Peng","doi":"10.1016/j.tust.2025.106653","DOIUrl":"10.1016/j.tust.2025.106653","url":null,"abstract":"<div><div>The determination of discharge and hydraulic head of underground caverns is a crucial aspect for their engineering construction. The boundary of aquifer should be bounded for the calculation of seepage field of underground caverns in coastal areas. Therefore, analytical solutions for discharge and hydraulic head of underground caverns with square arch cross-section in a three-dimensional(3D) bounded unconfined aquifer are presented in this paper. Fourier series expansion and Laplace transform are used to obtain a point sink solution. Solutions of discharge and hydraulic head caused by multiple caverns with square arch cross-section in the 3D bounded unconfined aquifer are obtained by integrating the point sink solution in cavern domain which includes cavern cavity, cavern surface and cavern outline (C-S-O integration method). The accuracy of the point sink solution and the cuboid cavern solution is verified by comparing with numerical solutions obtained by COMSOL. The comparison shows that the analytical solutions agree well with numerical solutions. The effects of vertical hydraulic conductivity and specific yield on cavern discharge and hydraulic head are investigated. Treatment methods for actual projects which usually involve the construction of multiple caverns with square arch cross-section, and the long axis of the cavern forms an angle <em>θ</em> with the horizontal axis are presented. A more simplified integration method (S-O), which includes only cavern surface and cavern outline, is proposed, and compared with the results of C-S-O, which indicates that the simplified approach achieves comparable accuracy. The study offers theoretical reference for the prediction of discharge and groundwater level during the excavation and operation of underground caverns.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106653"},"PeriodicalIF":6.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868653","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 : 2025-04-24DOI: 10.1016/j.tust.2025.106649
Yanzi Xia , Chi Zhang , Min Zhang , Hong Zhang , Bo Wang
Spiral tunnels, increasingly used in mountainous expressways to traverse significant elevation differences, are frequently associated with traffic safety concerns due to their extended, continuous turns, which can impair driving cognition. Guided by the self-explaining road (SER) principle (Theeuwes, 2021) – which advocates environmental design that enables adequate and swift perception – this study examined both the cognitive characteristics of driving in spiral tunnels and the influence of environment on driving cognition. We first investigated the cognitive significance of tunnel environmental elements through a questionnaire survey, then conducted curvature perception experiments with 20 drivers using real-world driving videos to test fixation duration, fixation number, degree of curvature illusion, and reaction time, and finally analyzed the relations of these indicators. Results showed that compared to ordinary curved tunnels, spiral tunnels induced shorter fixation durations, lower curvature estimation (3.69 %) and prolonged reaction time (39.8 s). Entrance section triggered the longest reaction time (29.9 s) due to attention dispersion, while exit zones exhibited the most serious curvature illusion (28 %). Although the orientation of roadway (OR) was considered the most critical element, environmental elements have complex relationship with visual attention in spiral tunnels. Additionally, fixation duration and number exhibit a negative correlation with curvature illusion reaction time, suggesting adequate environmental information may improve curvature perception. The results reveal that driving cognition in spiral tunnels faces more unfavorable conditions, especially in the entrance and exit sections. Moderate supplementation of environmental information may optimize driving cognition. This study provides stakeholders with cognition-informed optimization strategies for traffic safety in geometrically constrained environments.
{"title":"Characterizing the driving cognition within spiral tunnels based on SER principle","authors":"Yanzi Xia , Chi Zhang , Min Zhang , Hong Zhang , Bo Wang","doi":"10.1016/j.tust.2025.106649","DOIUrl":"10.1016/j.tust.2025.106649","url":null,"abstract":"<div><div>Spiral tunnels, increasingly used in mountainous expressways to traverse significant elevation differences, are frequently associated with traffic safety concerns due to their extended, continuous turns, which can impair driving cognition. Guided by the self-explaining road (SER) principle (<span><span>Theeuwes, 2021</span></span>) – which advocates environmental design that enables adequate and swift perception – this study examined both the cognitive characteristics of driving in spiral tunnels and the influence of environment on driving cognition. We first investigated the cognitive significance of tunnel environmental elements through a questionnaire survey, then conducted curvature perception experiments with 20 drivers using real-world driving videos to test fixation duration, fixation number, degree of curvature illusion, and reaction time, and finally analyzed the relations of these indicators. Results showed that compared to ordinary curved tunnels, spiral tunnels induced shorter fixation durations, lower curvature estimation (3.69 %) and prolonged reaction time (39.8 s). Entrance section triggered the longest reaction time (29.9 s) due to attention dispersion, while exit zones exhibited the most serious curvature illusion (28 %). Although the orientation of roadway (OR) was considered the most critical element, environmental elements have complex relationship with visual attention in spiral tunnels. Additionally, fixation duration and number exhibit a negative correlation with curvature illusion reaction time, suggesting adequate environmental information may improve curvature perception. The results reveal that driving cognition in spiral tunnels faces more unfavorable conditions, especially in the entrance and exit sections. Moderate supplementation of environmental information may optimize driving cognition. This study provides stakeholders with cognition-informed optimization strategies for traffic safety in geometrically constrained environments.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106649"},"PeriodicalIF":6.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868723","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 : 2025-04-24DOI: 10.1016/j.tust.2025.106678
Leilei Liu, Weizhang Liang, Guoyan Zhao, Pan Wu
Accurately predicting the long-term rockburst risk is essential to ensure the underground excavation safety. In this study, a cluster-based ensemble learning (CEL) model was developed by aggregating balanced iterative reducing and clustering using hierarchies (BIRCH) and random forest (RF) algorithms to predict the long-term rockburst risk. A total of 259 historical rockburst cases with six indicators were collected to verify the feasibility of the proposed CEL-RF model. To improve the reliability of the model, the Bayesian optimization (BO) and five-fold cross validation (CV) approaches were combined to search the optimal hyperparameters and weights of RF classifiers. The comprehensive performance of models was compared and evaluated by five metrics (accuracy, Cohen’s Kappa, macro average of the precision, recall and F1-score). The results indicated that the CEL-RF model performed best with the accuracy of 0.885. In addition, the CEL-RF model was applied to predict the probability of rockburst risk in four underground gold mines and the results were consistent with the field conditions. The Shapley additive explanations (SHAP) method revealed that the elastic energy index Wet was the most important indicator. Overall, the proposed CEL-RF model is a promising model for long-term rockburst risk prediction.
{"title":"A novel cluster-based ensemble learning method for long-term rockburst risk prediction and its application","authors":"Leilei Liu, Weizhang Liang, Guoyan Zhao, Pan Wu","doi":"10.1016/j.tust.2025.106678","DOIUrl":"10.1016/j.tust.2025.106678","url":null,"abstract":"<div><div>Accurately predicting the long-term rockburst risk is essential to ensure the underground excavation safety. In this study, a cluster-based ensemble learning (CEL) model was developed by aggregating balanced iterative reducing and clustering using hierarchies (BIRCH) and random forest (RF) algorithms to predict the long-term rockburst risk. A total of 259 historical rockburst cases with six indicators were collected to verify the feasibility of the proposed CEL-RF model. To improve the reliability of the model, the Bayesian optimization (BO) and five-fold cross validation (CV) approaches were combined to search the optimal hyperparameters and weights of RF classifiers. The comprehensive performance of models was compared and evaluated by five metrics (accuracy, Cohen’s Kappa, macro average of the precision, recall and <em>F</em><sub>1</sub>-score). The results indicated that the CEL-RF model performed best with the accuracy of 0.885. In addition, the CEL-RF model was applied to predict the probability of rockburst risk in four underground gold mines and the results were consistent with the field conditions. The Shapley additive explanations (SHAP) method revealed that the elastic energy index <em>W<sub>et</sub></em> was the most important indicator. Overall, the proposed CEL-RF model is a promising model for long-term rockburst risk prediction.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"162 ","pages":"Article 106678"},"PeriodicalIF":6.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864608","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 : 2025-04-24DOI: 10.1016/j.tust.2025.106628
Bassam Mohammed Al-Washali , Kai Yao , Umashankaran Satchithananthan , Zhanyong Yao , Abdullah M. Tawfek , Yutao Pan , Michael Beer
The stability of tunnel faces under the stationary condition of an Earth Pressure Balance (EPB) machine is critical in tunnel construction. While extensive research has focused on the operational stability of tunnel faces, a significant gap remains in understanding the influence of cutterhead geometry on face stability under stationary phases. This study employs three-dimensional (3D) Finite Element (FE) analysis to investigate tunnel face stability in clay and sandy soils, emphasizing the effect of cutterhead opening area ratio (COA), cutterhead shape, and tunnel cover depth (C/D) on stability under stationary conditions. Three distinct cutterhead shapes, exhibiting varying COAs (35 %, 40 %, and 45 %), were analysed across a range of cover depths from 0.5D to 4.0D (D represents the tunnel diameter). The results indicate that larger COAs (45 %) significantly increase soil displacement and instability risks, particularly in clay soils, with critical displacements occurring after reductions of up to 40 % in support pressure. In contrast, sandy soils demonstrated enhanced stability even with larger COAs. Furthermore, the study revealed a significant influence of cutterhead design on soil displacement and support pressure. Cutterhead shape 3, characterized by symmetrical openings and a large central panel, exhibited superior performance, minimizing soil displacement and requiring up to 20 % less support pressure compared to other cutterhead shapes investigated in this study. The cover depth in the three shapes was found to influence stability, with deeper tunnels (C/D = 4.0D) at various COAs experiencing greater displacement and requiring higher support pressures, especially in clay soils. Stress distribution analysis revealed that increased COA and larger cover depths contribute to higher horizontal stress, which exacerbates face instability. Additionally, clay soils exhibited a higher propensity for instability compared to sandy soils, particularly under conditions of larger COAs and deeper cover depths. This research provides a novel approach to optimizing EPB machine performance by considering face stability in the cutterhead opening areas. The findings offer valuable insights for tunnel boring machine (TBM) design and operational planning in various ground conditions.
{"title":"Numerical investigation on the effect of cutterhead shapes on tunnel face stability","authors":"Bassam Mohammed Al-Washali , Kai Yao , Umashankaran Satchithananthan , Zhanyong Yao , Abdullah M. Tawfek , Yutao Pan , Michael Beer","doi":"10.1016/j.tust.2025.106628","DOIUrl":"10.1016/j.tust.2025.106628","url":null,"abstract":"<div><div>The stability of tunnel faces under the stationary condition of an Earth Pressure Balance (EPB) machine is critical in tunnel construction. While extensive research has focused on the operational stability of tunnel faces, a significant gap remains in understanding the influence of cutterhead geometry on face stability under stationary phases. This study employs three-dimensional (3D) Finite Element (FE) analysis to investigate tunnel face stability in clay and sandy soils, emphasizing the effect of cutterhead opening area ratio (COA), cutterhead shape, and tunnel cover depth (C/D) on stability under stationary conditions. Three distinct cutterhead shapes, exhibiting varying COAs (35 %, 40 %, and 45 %), were analysed across a range of cover depths from 0.5D to 4.0D (D represents the tunnel diameter). The results indicate that larger COAs (45 %) significantly increase soil displacement and instability risks, particularly in clay soils, with critical displacements occurring after reductions of up to 40 % in support pressure. In contrast, sandy soils demonstrated enhanced stability even with larger COAs. Furthermore, the study revealed a significant influence of cutterhead design on soil displacement and support pressure. Cutterhead shape 3, characterized by symmetrical openings and a large central panel, exhibited superior performance, minimizing soil displacement and requiring up to 20 % less support pressure compared to other cutterhead shapes investigated in this study. The cover depth in the three shapes was found to influence stability, with deeper tunnels (C/D = 4.0D) at various COAs experiencing greater displacement and requiring higher support pressures, especially in clay soils. Stress distribution analysis revealed that increased COA and larger cover depths contribute to higher horizontal stress, which exacerbates face instability. Additionally, clay soils exhibited a higher propensity for instability compared to sandy soils, particularly under conditions of larger COAs and deeper cover depths. This research provides a novel approach to optimizing EPB machine performance by considering face stability in the cutterhead opening areas. The findings offer valuable insights for tunnel boring machine (TBM) design and operational planning in various ground conditions.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106628"},"PeriodicalIF":6.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868882","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 : 2025-04-24DOI: 10.1016/j.tust.2025.106674
Liqun Li , Zhiyi Chen , Ping Lu , Yu Huang
Tunnels crossing active faults are vulnerable to severe damage under near-fault earthquakes due to the combined effects of co-seismic dislocation and complex ground motion wavefields. To capture the spatiotemporal features of near-fault ground motion and their effects on tunnel structures, this study proposes a physics-based source-to-structure simulation framework. A frequency-wavenumber (F-K) integration method is used to reconstruct broadband seismic wavefields (0.1–10 Hz) based on the finite-fault source model of the 2022 Mw 6.6 Menyuan earthquake. These waveforms are discretized and applied to a nonlinear finite element model of the Daliang Tunnel, which experienced severe damage during the event. The simulated displacement time histories match well with classical finite fault solutions, and the spatial distribution of co-seismic displacements shows good agreement with InSAR observations, especially in amplitude and trend. Within 50 km of the epicenter, the simulated peak ground accelerations (PGAs) agree closely with strong motion records, and the Fourier spectra below 1 Hz are consistent with observed data. Directional velocity pulses and fling-step effects are captured by analyzing PGV/PGA ratios in strike and normal directions, and further confirmed by wavelet transform analysis of near-fault station responses. Structural analysis reveals that fault-crossing segments experience quasi-static shearing dominated by dislocation, while segments farther from the fault are mainly affected by directional velocity pulses. The dynamic stress induced by these pulses accounts for up to 57.1 % of the quasi-static stress. The results highlight the critical importance of low-frequency ground motion components and directional effects in evaluating the seismic response and damage mechanisms of cross-fault tunnels.
{"title":"Dynamic response analysis of cross-fault tunnel considering source-to-structure seismic input and near-fault effect","authors":"Liqun Li , Zhiyi Chen , Ping Lu , Yu Huang","doi":"10.1016/j.tust.2025.106674","DOIUrl":"10.1016/j.tust.2025.106674","url":null,"abstract":"<div><div>Tunnels crossing active faults are vulnerable to severe damage under near-fault earthquakes due to the combined effects of co-seismic dislocation and complex ground motion wavefields. To capture the spatiotemporal features of near-fault ground motion and their effects on tunnel structures, this study proposes a physics-based source-to-structure simulation framework. A frequency-wavenumber (F-K) integration method is used to reconstruct broadband seismic wavefields (0.1–10 Hz) based on the finite-fault source model of the 2022 Mw 6.6 Menyuan earthquake. These waveforms are discretized and applied to a nonlinear finite element model of the Daliang Tunnel, which experienced severe damage during the event. The simulated displacement time histories match well with classical finite fault solutions, and the spatial distribution of co-seismic displacements shows good agreement with InSAR observations, especially in amplitude and trend. Within 50 km of the epicenter, the simulated peak ground accelerations (PGAs) agree closely with strong motion records, and the Fourier spectra below 1 Hz are consistent with observed data. Directional velocity pulses and fling-step effects are captured by analyzing PGV/PGA ratios in strike and normal directions, and further confirmed by wavelet transform analysis of near-fault station responses. Structural analysis reveals that fault-crossing segments experience quasi-static shearing dominated by dislocation, while segments farther from the fault are mainly affected by directional velocity pulses. The dynamic stress induced by these pulses accounts for up to 57.1 % of the quasi-static stress. The results highlight the critical importance of low-frequency ground motion components and directional effects in evaluating the seismic response and damage mechanisms of cross-fault tunnels.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"162 ","pages":"Article 106674"},"PeriodicalIF":6.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864610","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 : 2025-04-24DOI: 10.1016/j.tust.2025.106660
Yongguang Wang , Mengtao Wu , Jun Yang
Accurately capturing the seismic response of underground structures subjected to obliquely incident seismic waves, particularly when the angle of incidence surpasses the critical value, remains a challenging task in earthquake engineering. To address this gap, this paper presents a three-dimensional (3D) nonlinear seismic analysis of subway stations embedded in a layered site, specifically in response to obliquely incident shear (SV) waves at arbitrary angles. An innovative procedure, termed the coupled dynamic stiffness matrix–finite element method (DSM-FEM), is introduced to enable seismic input by transforming responses induced by arbitrarily incoming SV waves into equivalent nodal loads. To accurately simulate wave propagation within the site, a viscous-spring artificial boundary is utilized, while a nonlinear generalized Masing model that incorporates modified damping is employed. Using the Daikai subway station as a benchmark, the research examines the effects of varying oblique incident angles on the structural response, taking into account dynamic soil-structure interaction. The results reveal that the maximum response, including peak deformation, internal forces, Mises stress, occurs when the incident angle approaches the critical value. Beyond this critical angle, the seismic response notably diminishes. Additionally, the influence of horizontal incident angles is found to be noticeable, leading to variations in deformation patterns and internal forces across different structural components. Specifically, it has been observed that the drift ratio, displacement, shear force, acceleration, and Mises stress exhibit a decreasing trend as the horizontal incident angles increase. These findings highlight the significance of considering non-vertical input ground motion in seismic analysis, and offer valuable insights for the structural design and safety evaluation of underground structures.
{"title":"Nonlinear seismic analysis of subway station − layered site under obliquely incident shear waves with arbitrary angles","authors":"Yongguang Wang , Mengtao Wu , Jun Yang","doi":"10.1016/j.tust.2025.106660","DOIUrl":"10.1016/j.tust.2025.106660","url":null,"abstract":"<div><div>Accurately capturing the seismic response of underground structures subjected to obliquely incident seismic waves, particularly when the angle of incidence surpasses the critical value, remains a challenging task in earthquake engineering. To address this gap, this paper presents a three-dimensional (3D) nonlinear seismic analysis of subway stations embedded in a layered site, specifically in response to obliquely incident shear (SV) waves at arbitrary angles. An innovative procedure, termed the coupled dynamic stiffness matrix–finite element method (DSM-FEM), is introduced to enable seismic input by transforming responses induced by arbitrarily incoming SV waves into equivalent nodal loads. To accurately simulate wave propagation within the site, a viscous-spring artificial boundary is utilized, while a nonlinear generalized Masing model that incorporates modified damping is employed. Using the Daikai subway station as a benchmark, the research examines the effects of varying oblique incident angles on the structural response, taking into account dynamic soil-structure interaction. The results reveal that the maximum response, including peak deformation, internal forces, Mises stress, occurs when the incident angle approaches the critical value. Beyond this critical angle, the seismic response notably diminishes. Additionally, the influence of horizontal incident angles is found to be noticeable, leading to variations in deformation patterns and internal forces across different structural components. Specifically, it has been observed that the drift ratio, displacement, shear force, acceleration, and Mises stress exhibit a decreasing trend as the horizontal incident angles increase. These findings highlight the significance of considering non-vertical input ground motion in seismic analysis, and offer valuable insights for the structural design and safety evaluation of underground structures.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106660"},"PeriodicalIF":6.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868881","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 : 2025-04-24DOI: 10.1016/j.tust.2025.106670
Liang Ma , Tengfei An , Runhan Zhao , Tianxiang Liu , Wenli Liu
As urban water supply pipelines continue to expand, an increasing number of pipelines encounter issues such as aging and corrosion, resulting in frequent leakages. Accurately identifying leakage signals is challenging due to significant background noise complicating signal isolation. To address this issue, this paper proposes a signal denoising and feature enhancement method to capture leakage signals and amplifiy leakage feature based on rime optimization algorithm, variational mode decomposition and teager energy operator-symbolic entropy (RIME-VMD-TEOSE). First, the RIME is employed to optimize VMD, enabling the adaptive selection of key parameters. The bubble entropy of the denoised signal is computed to construct a fault feature vector, which is fed into the RIME-optimized extreme learning machine (ELM) for leakage condition identification. Second, the Teager energy operator is applied to enhance the intrinsic mode functions (IMFs) obtained from the RIME-VMD, and the symbolic entropy of the enhanced signals is calculated to construct a leakage feature vector, which is then input into the RIME-optimized ELM for leakage pressure identification. Finally, the proposed signal denoising and enhancement methods were validated using pipeline experimental data, achieving a recognition accuracy of 95.71 % for distinguishing between large leakage, small leakage, normal, and knock signals, and 97.69 % for identifying pipeline leakage pressures of 0.4 MPa and 0.6 MPa. These results demonstrate the effectiveness of the proposed methods in improving the accuracy and reliability of pipeline leakage detection and pressure identification, contributing to better monitoring and maintenance of urban water supply systems.
{"title":"Signal processing techniques for detecting leakage in urban water supply pipelines: Denoising and feature enhancement","authors":"Liang Ma , Tengfei An , Runhan Zhao , Tianxiang Liu , Wenli Liu","doi":"10.1016/j.tust.2025.106670","DOIUrl":"10.1016/j.tust.2025.106670","url":null,"abstract":"<div><div>As urban water supply pipelines continue to expand, an increasing number of pipelines encounter issues such as aging and corrosion, resulting in frequent leakages. Accurately identifying leakage signals is challenging due to significant background noise complicating signal isolation. To address this issue, this paper proposes a signal denoising and feature enhancement method to capture leakage signals and amplifiy leakage feature based on rime optimization algorithm, variational mode decomposition and teager energy operator-symbolic entropy (RIME-VMD-TEOSE). First, the RIME is employed to optimize VMD, enabling the adaptive selection of key parameters. The bubble entropy of the denoised signal is computed to construct a fault feature vector, which is fed into the RIME-optimized extreme learning machine (ELM) for leakage condition identification. Second, the Teager energy operator is applied to enhance the intrinsic mode functions (IMFs) obtained from the RIME-VMD, and the symbolic entropy of the enhanced signals is calculated to construct a leakage feature vector, which is then input into the RIME-optimized ELM for leakage pressure identification. Finally, the proposed signal denoising and enhancement methods were validated using pipeline experimental data, achieving a recognition accuracy of 95.71 % for distinguishing between large leakage, small leakage, normal, and knock signals, and 97.69 % for identifying pipeline leakage pressures of 0.4 MPa and 0.6 MPa. These results demonstrate the effectiveness of the proposed methods in improving the accuracy and reliability of pipeline leakage detection and pressure identification, contributing to better monitoring and maintenance of urban water supply systems.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"162 ","pages":"Article 106670"},"PeriodicalIF":6.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864609","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 : 2025-04-23DOI: 10.1016/j.tust.2025.106684
Xue Wang , Li Yu , Mingnian Wang , Junqi Li , Yuan Liu , Keyi Liu , Zan You
Compared to porous burners using gaseous alkanes or alcohols, the combustion characteristics of diesel pool fires more closely resemble actual tunnel fire scenarios. Diesel fires may exhibit more complex combustion behavior and higher flame burning rates under longitudinal ventilation, increasing the risk of fire spread within the tunnel. In a windy tunnel, the flame tilt angle and flame length are the two key parameters used to describe flame characteristics. This paper focuses on tunnels with steep gradients and small curvatures, establishing scaled models with varying curvatures and slopes to experimentally study the flame characteristics of diesel pool fires under the influence of longitudinal ventilation. The results show that a linear correlation between the logarithm of the mass loss rate and the logarithm of the measured fire source length in windless conditions. The square root of the ratio of longitudinal ventilation speed to the side length of the fire source is directly proportional to the fuel mass loss rate per unit area under longitudinal ventilation. Secondly, the flame title angle is linearly correlated with the tunnel slope in windless tunnel, and the flame tilt angle shows a slight increase as the curvature radius decreases. The flame title angle is linearly correlated with the longitudinal wind speed. Furthermore, Hu’s flame tilt angle model was refined for positive slope, low slope and negative slope tunnels under longitudinal ventilation. Finally, new flame length models for positive slope, low slope and negative slope tunnels under longitudinal ventilation were proposed based on theoretical analysis and experimental data.
{"title":"Experimental study on flame characteristics over diesel pool fires under the longitudinal ventilation in curved and inclined tunnels","authors":"Xue Wang , Li Yu , Mingnian Wang , Junqi Li , Yuan Liu , Keyi Liu , Zan You","doi":"10.1016/j.tust.2025.106684","DOIUrl":"10.1016/j.tust.2025.106684","url":null,"abstract":"<div><div>Compared to porous burners using gaseous alkanes or alcohols, the combustion characteristics of diesel pool fires more closely resemble actual tunnel fire scenarios. Diesel fires may exhibit more complex combustion behavior and higher flame burning rates under longitudinal ventilation, increasing the risk of fire spread within the tunnel. In a windy tunnel, the flame tilt angle and flame length are the two key parameters used to describe flame characteristics. This paper focuses on tunnels with steep gradients and small curvatures, establishing scaled models with varying curvatures and slopes to experimentally study the flame characteristics of diesel pool fires under the influence of longitudinal ventilation. The results show that a linear correlation between the logarithm of the mass loss rate and the logarithm of the measured fire source length in windless conditions. The square root of the ratio of longitudinal ventilation speed to the side length of the fire source is directly proportional to the fuel mass loss rate per unit area under longitudinal ventilation. Secondly, the flame title angle is linearly correlated with the tunnel slope in windless tunnel, and the flame tilt angle shows a slight increase as the curvature radius decreases. The flame title angle is linearly correlated with the longitudinal wind speed. Furthermore, Hu’s flame tilt angle model was refined for positive slope, low slope and negative slope tunnels under longitudinal ventilation. Finally, new flame length models for positive slope, low slope and negative slope tunnels under longitudinal ventilation were proposed based on theoretical analysis and experimental data.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"162 ","pages":"Article 106684"},"PeriodicalIF":6.7,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859052","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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