Tunnelling and Underground Space Technology最新文献

{"title":"Extraction of image fractal characteristics of rock chips based on the Sandbox method and analysis of shield tunneling performance","authors":"Changbin Yan ,&nbsp;Yuxuan Shi ,&nbsp;Zihe Gao ,&nbsp;Weiwei Zhan","doi":"10.1016/j.tust.2025.106751","DOIUrl":"10.1016/j.tust.2025.106751","url":null,"abstract":"<div><div>The size distribution of rock chips can fully reflect the performance of shield machine, and existing size distribution indicators suffer from low efficiency and poor accuracy. Therefore, the aim is to find an accurate and rapid quantitative indicator to characterize the rock chips size distribution and address the engineering issues of shield machine rock-breaking efficiency analysis and tunneling parameter optimization. In this study, five groups of rock chips with different quality components and eight shooting heights were designed to explore the performance and applicability of the image fractal dimension (<em>D</em>), a quantitative indicator of rock chip size distribution based on the Sandbox fractal method, and also to compare it with the traditional Box-counting method. Additionally, an analysis of 136 groups of rock chips data from different surrounding rock grades was conducted to investigate the correlation between image fractal dimension and common shield performance indexes, such as the average single cutter thrust force (<em>F</em>_n), and penetration depth (<em>P</em>_rev). The results indicate that the experimental platform constructed in this study, with image data acquired at a shooting height of 120 cm, is well-suited for calculating image fractal dimension. Compared to the traditional Box-counting method, the Sandbox method demonstrates higher sensitivity to changes in the particle size distribution of rock chips and does not impose restrictions on input image size, making it more appropriate for quantitative analysis. The image fractal dimension decreases as the proportion of large-sized rock chips increases. Under the same surrounding rock conditions, the image fractal dimension of rock chips is positively correlated with the logarithm of specific energy (<em>SE</em>) and negatively correlated with the logarithm of coarseness index (<em>CI</em>), effectively reflecting shield rock-breaking efficiency. Based on the correlation between image fractal dimension and <em>SE</em>, the optimal ranges of <em>F</em>_n and <em>S</em>/<em>P</em>_rev under grade II, III, IV, and V surrounding rock conditions can be determined, thereby enabling the optimization of tunneling performance.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106751"},"PeriodicalIF":6.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144147429","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":"Surrounding rock grade identification of deep TBM tunnel based on data decomposition and model fusion","authors":"Kang Fu ,&nbsp;Daohong Qiu ,&nbsp;Yiguo Xue ,&nbsp;Fanmeng Kong ,&nbsp;Huimin Gong","doi":"10.1016/j.tust.2025.106760","DOIUrl":"10.1016/j.tust.2025.106760","url":null,"abstract":"<div><div>The automatic identification of surrounding rock grade is a key challenge in the TBM construction of deep tunnels. This study aims to develop an automatic identification system based on TBM ascending section tunneling data to provide accurate guidance for stable section tunneling. A total of 6734  m of per-second TBM tunneling data was collected, and a preprocessing method for null and outlier values was proposed. The TBM complete tunneling cycle was divided into empty pushing, ascending, stable, and descending sections. Based on improved ICEEMDAN and HWPE, the <em>T</em> and <em>F</em> curves of the ascending section were decomposed, feature entropy values of IMF components were extracted, and an IMF component <em>HWPE</em> sample database was constructed. A Stacking ensemble framework was developed, and the Stacking-BIGRU model achieved identification accuracies of 95.0 %, 100.0 %, 97.5 %, and 90.0 % for grade II, IIIa, IIIb, and IV rock, respectively, with an overall accuracy of 95.625 %. Compared with traditional EMD and PE, the improved ICEEMDAN and HWPE enhanced the overall accuracy by 13.33 % and 7.75 %, respectively. The proposed system can effectively extract feature information from ascending section tunneling data, enabling accurate surrounding rock grade identification.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106760"},"PeriodicalIF":6.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134900","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 parametric method for maximum key block on tunnels excavation and its verification","authors":"Yong Yang ,&nbsp;Minsi Zhang ,&nbsp;Shuhong Wang ,&nbsp;Wenhua Zha","doi":"10.1016/j.tust.2025.106608","DOIUrl":"10.1016/j.tust.2025.106608","url":null,"abstract":"<div><div>During the engineering design stage, it is challenging to precisely identify the number and spatial distribution of joints within rock masses. To address this, joint orientations are assumed to be constant and evaluate all possible combinations of joints and excavation surfaces to identify the most critical scenario. The maximum key block serves as a vital indicator for tunnel alignment optimization. However, existing methods are limited and primarily focus on pyramidal blocks. In practice, wedged blocks (non-pyramidal) are common and often exhibit larger volumes. This study proposes a parametric method to determine the maximum key blocks formed by four joint groups on tunnel excavation surfaces. The method uniformly characterizes both wedged and pyramidal blocks using a parameter <em>t</em>, enabling efficient identification of maximum key blocks. Implemented through a computer program, the method was validated in an engineering case study, revealing that wedged blocks constitute the maximum key block in 62.7% of scenarios. This finding emphasizes the necessity of incorporating both block types in stability analysis.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106608"},"PeriodicalIF":6.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134899","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":"Game engine-driven synthetic point cloud generation method for LiDAR-based defect detection in sewers","authors":"Minghao Li,&nbsp;Xin Feng,&nbsp;Ziyu Wu,&nbsp;Juju Bai,&nbsp;Fengyuan Yang","doi":"10.1016/j.tust.2025.106755","DOIUrl":"10.1016/j.tust.2025.106755","url":null,"abstract":"<div><div>3D point clouds acquired from emerging light detection and ranging (LiDAR) enable quantitative defect inspection for urban sewers. Defect detection of sewer point clouds is an essential step in deep-learning-based condition assessment; however, it faces challenges related to data scarcity. This study proposes a novel LiDAR simulation-based synthetic point-cloud data generation methodology driven by game engines, which addresses issues arising from geometric occlusions and the defect randomization. Evaluation experiments were conducted to validate the enhancement provided by the synthetic point clouds. The results indicated that the synthetic data significantly enhanced the accuracy of detecting corrosion and spalling defects by 17.90% and 4.69%, 15.22% and 11.69%, 15.56% and 15.21%, and 10.32% and 1.40% for 50, 100, 200, and 300 real scans, respectively. In addition, pre-trained models outperformed the widely used hybrid training approach, solving knowledge transfer between synthetic and real data. The proposed method alleviates data scarcity and contributes to automated defect segmentation in sewer point clouds.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106755"},"PeriodicalIF":6.7,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144114951","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":"Optimal range of ventilation velocity in tunnel fires under subcritical longitudinal ventilation","authors":"Dong Yang ,&nbsp;Zhijie Lin ,&nbsp;Xianyuan Lu ,&nbsp;Xin Guo ,&nbsp;Haoyue Yu ,&nbsp;Tao Du","doi":"10.1016/j.tust.2025.106753","DOIUrl":"10.1016/j.tust.2025.106753","url":null,"abstract":"<div><div>In tunnel fires under longitudinal ventilation, a large ventilation velocity, such as the critical velocity, may disrupt smoke stratification downstream of the fire source. During the early stages of a fire, when evacuation is in progress, a subcritical ventilation velocity can strike a balance between maintaining smoke stratification and restricting backlayering length. To determine the optimal range of subcritical ventilation velocity, both brine-water and fire smoke experiments are conducted, considering the combined effects of smoke backlayering and stratification. Due to boundary buoyancy loss, the backlayering length observed in fire smoke experiments is slightly shorter than that in brine-water experiments. Smoke stratification is characterized using the thickness of the smoke layer and a dimensionless temperature rise. The thickness of the smoke layer is primarily influenced by ventilation velocity and source buoyancy flux, with minimal impact from boundary heat transfer during the early stages of a tunnel fire. Furthermore, the dimensionless temperature rise tends to increase with higher source buoyancy flux and lower ventilation velocity. Based on human safety criteria, i.e., backlayering length is manageable and smoke does not descend into human activity zone, the optimal range of subcritical ventilation velocity is proposed. These findings provide valuable insights for optimizing ventilation strategies in tunnel fires under subcritical longitudinal ventilation.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106753"},"PeriodicalIF":6.7,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115573","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":"Optimizing artificial lighting conditions for rock plane detection on tunnel faces: A controlled experiment using smartphone videogrammetry","authors":"Nirandoal Cheng ,&nbsp;Mohd Ashraf Mohamad Ismail ,&nbsp;Fatin Nadhirah Ahmad Pauzi ,&nbsp;Yasuhiro Yokota ,&nbsp;Hayato Tobe","doi":"10.1016/j.tust.2025.106756","DOIUrl":"10.1016/j.tust.2025.106756","url":null,"abstract":"<div><div>The study investigates the influence of artificial lighting conditions on the accuracy of detecting rock planes on tunnel faces using videogrammetry. A controlled experiment was conducted employing 3D-printed models with predefined dip angles and dip directions, illuminated under varying conditions of light intensity, color temperature, and angles. The research utilized advanced imaging techniques to capture video data at multiple distances and angles, followed by detailed 3D point cloud reconstruction and analysis. Results demonstrate that lighting parameters significantly affect videogrammetric outcomes. Optimal configurations such as 5500 K color temperature and 1000 lx intensity enhanced point cloud density and reduced errors, achieving precise detection of rock planes. Oblique video captures outperformed straight-on captures, providing better coverage of inclined surfaces and reducing Root Mean Square Error (RMSE) in measurements. In contrast, combined lighting setups introduced inconsistencies, leading to increased variability. The findings underline the importance of tailored lighting and capture strategies to improve detection accuracy in tunnel environments. Practical guidelines derived from this research offer valuable insights for optimizing videogrammetric workflows in engineering and geotechnical applications.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106756"},"PeriodicalIF":6.7,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105477","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":"Mwd-based real-time identification of rock weathering: A comparison of supervised and unsupervised machine learning methods","authors":"Yang Li ,&nbsp;Jiayao Chen ,&nbsp;Yifan Shen ,&nbsp;Qian Fang ,&nbsp;Jianhong Man","doi":"10.1016/j.tust.2025.106744","DOIUrl":"10.1016/j.tust.2025.106744","url":null,"abstract":"<div><div>A large-scale database linking six-dimensional tunneling parameters to rock weathering conditions was constructed from measurement-while-drilling (MWD) data during tunnel construction utilizing the drill-and-blast method. A data-driven predictive model was developed, integrating random search (RS) with a random forest (RF) classifier, for efficient, real-time identification of unexcavated rock weathering levels. Nine comparative models combining CART and XGBoost with hyperparameter optimization were also evaluated using the <em>Macro F</em>₁ score. The classification performance, applicability, and generalization capabilities of the proposed model were analyzed. Additionally, several unsupervised models were employed for clustering analysis, leveraging inherent data characteristics. Results demonstrated that the RS-RF algorithm outperforms other models in identifying rock weathering levels, with rotation pressure as the primary classification feature. For large, highly similar datasets, supervised algorithms exhibited superiority over their unsupervised counterparts. Consequently, the proposed model enables optimal classification of rock weathering conditions, thereby providing essential information for subsequent support and measurement.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106744"},"PeriodicalIF":6.7,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115574","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":"Performance of pipeline suspension system for in-situ protecting large-diameter pressurized pipelines straddling deep braced excavation in clays","authors":"Panpan Guo ,&nbsp;Tianshe Sun ,&nbsp;Haibo Li ,&nbsp;Yixian Wang","doi":"10.1016/j.tust.2025.106752","DOIUrl":"10.1016/j.tust.2025.106752","url":null,"abstract":"<div><div>This paper investigates the in-situ protection technique for buried pipelines straddling deep braced excavation and the relevant structural performance. A deep braced excavation case history for constructing the West Yuanhetang tunnel in Suzhou, China is reported. The excavation is straddled by two shallowly-buried large-diameter pressurized pipelines, with a straddling distance of about 31 m. Considering the significance of the pipelines for the normal life of local citizens, in-situ protective measures is thus necessary for ensuring the pipeline serviceability and stability during excavation. In an attempt to overcome the shortcomings of traditional pipeline protection technique, a new pipeline protection technique based on the suspension method is proposed. This technique takes advantage of the excavation support system. It eliminates the need for installing an exclusive structure for suspending pipelines, which is frequently practiced in conventional methods. Moreover, the original use of several kinds of materials for restraining pipeline displacement and transferring pipeline weight also contributes to a better protection of the pipelines. Furthermore, the performance of the proposed pipeline suspension system during excavation is investigated by using three-dimensional finite element method. The method is validated via reproducing the observed typical behavior of the deep excavation. Results has shown that the maximum axial forces, shear forces, and bending moments in the suspension supporting beams, as well as the maximum axial forces in the finish-rolling screw-thread (FRST) steel bars and the maximum bending moments and shear forces in the composite steel beams, all exhibit a stepwise growth pattern as the construction stage progresses. This research provides practical reference for in-situ protection of buried pipelines within deep braced excavation.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106752"},"PeriodicalIF":6.7,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099751","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 simulation and experimental study on oxygenation of tunnel face in plateau tunnel construction","authors":"Feng Lu ,&nbsp;Jie Liu ,&nbsp;Wanqing Wang ,&nbsp;Haowen Zhou ,&nbsp;Guanding Yang ,&nbsp;Huyun Zhao","doi":"10.1016/j.tust.2025.106716","DOIUrl":"10.1016/j.tust.2025.106716","url":null,"abstract":"<div><div>In order to investigate the effect of different oxygenation schemes on oxygen enrichment under different working conditions during the construction of the tunnel face of a large section tunnel on a plateau highway and to solve the quantitative problem of the oxygen enrichment model, a full-size numerical model of the tunnel face and a 1:30 experimental model were established for a plateau highway tunnel. These were used for numerical simulation and experimental research. The results indicate that the oxygen enriched area is piled up in the shape of a round bench when a construction bench is present, whereas in the absence of a construction bench, the oxygen enriched area assumes the shape of a slanting droplet. Furthermore, the oxygen enriched programs with oxygen delivery distances of 9 m, 8 m, and 7 m are unable to deliver the oxygen to the tunnel face. In the absence of a construction bench, the oxygenation effect is enhanced when the distance between the oxygen outlet and the tunnel face is 0.5 m. The oxygen released from different locations in multiple ports is distributed along the tunnel’s oxygen distribution range, which extends from three ports to two ports to one port. The number of oxygen ports affects the initial velocity of oxygen, which is susceptible to wind flow field influence. It is challenging to direct the flow of oxygen along the oxygen ports. The oxygen enriched volume of the different oxygen enriched programs in the tunnel under different working conditions can be quantified according to the multivariate linear regression oxygen enriched model, which can serve as a reference for optimizing oxygen enriched programs.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106716"},"PeriodicalIF":6.7,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090126","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":"Reply to Discussion: On effects of critical tunnelling parameters on consolidation-associated long-term greenfield settlement due to shield tunnel in soft ground by J.N. Shirlaw, and S.J. Boone","authors":"Gang Zheng,&nbsp;Ruikun Wang,&nbsp;Huayang Lei,&nbsp;Xuesong Cheng,&nbsp;Eng-Choon Leong,&nbsp;Hualin Du","doi":"10.1016/j.tust.2025.106521","DOIUrl":"10.1016/j.tust.2025.106521","url":null,"abstract":"","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"163 ","pages":"Article 106521"},"PeriodicalIF":6.7,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084234","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}