Tunnelling and Underground Space Technology最新文献

{"title":"Pseudo-static analytical solution for seismic response of deep tunnels with arbitrary cross-sections considering interface slippage effects under vertically incident SV waves","authors":"Cheng Shi ,&nbsp;Lianjin Tao ,&nbsp;Peng Ding ,&nbsp;Haixiang Zhang ,&nbsp;Zhiyun Deng ,&nbsp;Xuefei Hong","doi":"10.1016/j.tust.2025.106693","DOIUrl":"10.1016/j.tust.2025.106693","url":null,"abstract":"<div><div>To evaluate the seismic response of deep tunnels, this study proposes an analytical solution for the seismic response of deep tunnels with arbitrary cross-sections based on the extended complex function method and the boundary collocation approach, which realistically accounts for the interface properties between the lining and the surrounding rock and the lining thickness. The accuracy of the computational results of the analytical solution is validated through numerical simulations based on three tunnels with typical cross-sections. Moreover, this study compares the advantages, disadvantages, and applicability of analytical solutions based on the conventional and extended complex function methods for seismic analysis of tunnels. Finally, the considerable influence of the stiffness ratio between the lining and the surrounding rock, the interface properties, and the cross-section geometry on the seismic response of the tunnel is evaluated. The results demonstrate that for horseshoe, rectangular and straight-wall-top-arch tunnels, the discrepancies between the analytical and dynamic numerical results are less than 2.20 %, 4.48 %, and 6.65 %, respectively. In comparison to the conventional complex function method, the extended complex function method has enhanced computational accuracy, however, it demands greater computational resources and is more intricate to operate. A positive correlation exists between the stiffness ratio between the lining and the surrounding rock and both lining thrust and moment, while a negative correlation is observed between the stiffness ratio and displacement. The thrust of the tunnel lining all decreases rapidly as the interfacial flexibility coefficient increases, but the effect of the flexibility coefficient on the moments and displacements of the tunnel lining varies for different cross-sections and is related to the ground conditions. The seismic response strength of tunnels with varying cross-sections is as follows: rectangular tunnel &gt; straight-wall-top-arch tunnel &gt; horseshoe tunnel &gt; circular tunnel. This solution can be readily implemented in preliminary analyses and predictions of seismic responses for deep tunnels with arbitrary cross-sections, thereby offering a theoretical foundation and a valuable tool for seismic design and safety assessment.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106693"},"PeriodicalIF":6.7,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882937","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}

{"title":"Prediction of rock-breaking forces of tunnel boring machine (TBM) disc cutter based on machine learning methods","authors":"Qi Geng ,&nbsp;Yufeng Huang ,&nbsp;Jianxun Chen ,&nbsp;Xuebin Wang ,&nbsp;Weiwei Liu ,&nbsp;Yanbin Luo ,&nbsp;Zeyu Zhang ,&nbsp;Min Ye","doi":"10.1016/j.tust.2025.106682","DOIUrl":"10.1016/j.tust.2025.106682","url":null,"abstract":"<div><div>Rock-breaking forces are crucial indicators in evaluating the performance of tunnel boring machine (TBM) disc cutters, impacting cutter selection, cutterhead design, and penetration parameters. To develop an accurate and reliable prediction model for the rock-breaking forces of TBM disc cutters, a model database containing 414 typical samples was constructed based on the widely approved full-scale linear rock-breaking tests. The model takes the following inputs: uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), cutter diameter (<em>D</em>), cutter ring tip width (<em>T</em>), penetration depth (<em>P</em>), and cutter spacing (<em>S</em>). The outputs are the normal and rolling rock-breaking forces. Four machine learning methods, i.e., back-propagation neural network (BP), support vector regression (SVR), K-nearest neighbors (KNN), and random forest (RF) were applied for the prediction model establishment and evaluation. Comparative analyses were performed against three well-known theoretical, semi-empirical, and empirical prediction formulas respectively. The results demonstrated that, despite the relatively small dataset, the predicted normal forces from BP, SVR, KNN and RF models achieved R-Square (R²) values of 0.82, 0.81, 0.77 and 0.89, respectively, significantly outperforming the other three prediction formulas. This confirmed the generalization and accuracy of machine learning algorithms. Among these models, the RF model showed the most stable predictive performance and was less sensitive to outliers. Further evaluations were performed using field penetration test data obtained from four TBM projects. Results showed that the machine learning models consistently achieved high prediction accuracy, whereas the three theoretical or empirical formulas were more affected by rock strength variations, and exhibited relatively poorer performance. The successful application and evaluation offered a valuable tool to assist TBM cutterhead/cutter design and operational parameters selection.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106682"},"PeriodicalIF":6.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878763","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}

{"title":"Development of shield waste slurry-based tail grouting material for slurry pressure balance (SPB) tunneling: A geopolymer consolidation method","authors":"Tianhua Wu ,&nbsp;Yongtao Gao ,&nbsp;Changfu Huang ,&nbsp;Yang Liu ,&nbsp;Yi Xing ,&nbsp;Yuandong Peng ,&nbsp;Xiaocheng Qu ,&nbsp;Yu Zhou","doi":"10.1016/j.tust.2025.106695","DOIUrl":"10.1016/j.tust.2025.106695","url":null,"abstract":"<div><div>Owing to the substantial production of waste slurry in slurry pressure balance (SPB) shield tunneling, there is an urgent need to recycle SPB shield waste slurry (SWS). In this study, the proposed recycling method involves employing the geopolymer consolidation approach to develop an innovative SWS-based shield tail grouting material comprising SWS, geopolymers, and accelerators. Via the application of the Taguchi method, the optimal dosage ratio for the new grouting material was designed. An investigation was conducted to examine the influence of each component on the working and strength properties of the grouting material, and the results revealed that the most significant factor is the waste slurry specific gravity (WSSG). Moreover, the optimal grout formulation parameters included a WSSG of 1.10 g·cm⁻³, a geopolymer content (GC) of 95 %, and an accelerator content (AC) of 7 %, with the verification error of the results not exceeding 6 %. The microscopic hydration mechanisms of typical mixtures were qualitatively and quantitatively characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR), and the main gelatinous hydration structure identified is C-S-H gel. The optimal sample exhibited the highest Ca and Si concentrations of 43.21 %, and its Si-O stretching vibration band demonstrated the lowest wavenumber at 966.30 cm⁻¹. On-site industrial tests were performed against the backdrop of the Hengqin Mangzhou slurry shield tunnel (φ = 15.01 m), and the findings suggested that approximately 20.6 tons of SPB waste slurry is utilized for grouting per ring of segments. Compared with traditional mortar, the onsite production of the new grout is cost-effective, efficient, and environmentally friendly. Moreover, on the basis of real-time monitoring, ground-penetrating radar (GPR), and opening detection approaches, the new grouting material exhibited excellent deformation control (surface and segment) and high backfill density and effectiveness. In this study, effective in site resource reutilization of SPB SWS was achieved, which conforms with dual carbon goals.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106695"},"PeriodicalIF":6.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878816","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}

{"title":"Critical velocity and back-layering length of arched tunnels with large sectional aspect ratios under different fire-source–side-wall distances","authors":"Xiaochun Zhang ,&nbsp;Baien Lyu ,&nbsp;Junhao Wen ,&nbsp;Yajun Huang ,&nbsp;Zhenyi Zhang ,&nbsp;Linjie Li","doi":"10.1016/j.tust.2025.106673","DOIUrl":"10.1016/j.tust.2025.106673","url":null,"abstract":"<div><div>With the continuous advancement of shield tunneling technology, the size of shield machines has also increased significantly. It is necessary to study the fire behavior in arched highway tunnels with large sectional aspect ratios under longitudinal ventilation. In a vehicle fire, the vehicle typically stops near the tunnel sidewall. This work used experiments and numerical simulations to investigate the influence of different fire source offset positions on the critical velocity in arched tunnels with large sectional aspect ratios. The results showed that: (1) In an arched tunnel, the critical velocity first decreases and then increases with increasing distance between the fire source center and the sidewall. (2) For car fires in arched tunnels, if the fire source is located in the center of the tunnel, the critical velocity is similar to that of the near-wall fire, and it does not always increase as the fire source approaches the sidewall. The predictive model for the critical velocity of arched tunnel offset fires with different sectional aspect ratios has been established. (3) In large section aspect ratio arched tunnels, the influence of different fire source distances from the sidewall on the back-layering length is more pronounced than in tunnels with small aspect ratios. In near-wall fires, the dimensionless control velocity still has a linear relationship with the dimensionless back-layering length in arched tunnels.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106673"},"PeriodicalIF":6.7,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876718","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}

{"title":"Resilience analysis of tunnel lining under creep-induced convergence of soft rock: Characterization and field application","authors":"Xiaoyun Shu ,&nbsp;Weizhong Chen ,&nbsp;Hongming Tian ,&nbsp;Zhende Zhu ,&nbsp;Jingqiang Yuan ,&nbsp;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 &lt; 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}

{"title":"Temperature decay and heat exhaust efficiency under ceiling multi-point centralized smoke exhaust in a ventilated tunnel","authors":"Peng Hu ,&nbsp;Maohua Zhong ,&nbsp;Huihang Cheng ,&nbsp;Junfeng Chen ,&nbsp;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}

{"title":"Analytical solutions for discharge and hydraulic head of three-dimensional underground caverns in coastal areas","authors":"Shaohui Du ,&nbsp;Yifan Zhang ,&nbsp;Lianzhi Yang ,&nbsp;Fanmin He ,&nbsp;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}

{"title":"Characterizing the driving cognition within spiral tunnels based on SER principle","authors":"Yanzi Xia ,&nbsp;Chi Zhang ,&nbsp;Min Zhang ,&nbsp;Hong Zhang ,&nbsp;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}

{"title":"A novel cluster-based ensemble learning method for long-term rockburst risk prediction and its application","authors":"Leilei Liu,&nbsp;Weizhang Liang,&nbsp;Guoyan Zhao,&nbsp;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>₁-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_et</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}

{"title":"Numerical investigation on the effect of cutterhead shapes on tunnel face stability","authors":"Bassam Mohammed Al-Washali ,&nbsp;Kai Yao ,&nbsp;Umashankaran Satchithananthan ,&nbsp;Zhanyong Yao ,&nbsp;Abdullah M. Tawfek ,&nbsp;Yutao Pan ,&nbsp;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}