Tunnelling and Underground Space Technology最新文献

{"title":"Stability of surrounding rock in karst formations and response mechanism of tunnel linings under high water pressure","authors":"An Pengtao ,&nbsp;Liu Xiong ,&nbsp;Ma Shaokun ,&nbsp;Zhang jiabing ,&nbsp;Huang zhen ,&nbsp;Fu Helin","doi":"10.1016/j.tust.2025.107113","DOIUrl":"10.1016/j.tust.2025.107113","url":null,"abstract":"<div><div>Under certain natural conditions, karst stratum tunnels may experience the buildup of water pressure behind their linings, which can jeopardize operational safety. Therefore, it is crucial to examine the distribution of water pressure and the structural response characteristics in karst strata tunnels under high water pressure environments. Firstly, a three-dimensional model test was constructed to reveal the influence mechanisms of cavity location and water pressure on the distribution characteristics of water pressure behind the tunnel lining, the stress state of the tunnel support structure, and the surrounding rock pressure. Building upon this, a numerical model was employed to further elucidate the characteristics of stress and deformation evolution in the lining under complex water pressure environments. The results indicate that: When cavities are located above or below the tunnel, the stress and deformation of the lining exhibit symmetry; cavities located directly above the tunnel pose the most unfavorable condition for the lining structure, with the safety coefficient at the vault being approximately 30 % of that for cavities located to the side or below under identical hydraulic head conditions. The eccentric stress state of lining cross-sections is closely related to the cavity location; sections distant from the cavity consistently experience eccentric tension and exhibit lower safety coefficients than other sections. The failure process of the lining under high water pressure can be divided into four stages: water seepage, crack initiation, crack propagation, and localized failure. The displacement of the lining presents a ‘cherry-shaped’ distribution with the concave side pointing towards the karst cavity. The closer the karst cavity is to the vault, the greater the deformation. For every 0.5 MPa increase in water pressure from 0.5 MPa to 3 MPa, the vault displacement increases from 0.85 mm to 18.12 mm, with growth rates of 158 %, 144 %, 72 %, 46 %, and 35 % respectively. The Mises stress within the lining forms a ‘maple leaf’ distribution, with a pronounced stress concentration in a 120° sector adjacent to the karst cavity.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"168 ","pages":"Article 107113"},"PeriodicalIF":7.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108559","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":"Mechanical performance of novel joints in prefabricated UHPC panels for shield tunnel reinforcement: An experimental and numerical investigation","authors":"Zhen Li ,&nbsp;Xuezeng Liu ,&nbsp;Hehua Zhu ,&nbsp;Gang Shi","doi":"10.1016/j.tust.2025.107108","DOIUrl":"10.1016/j.tust.2025.107108","url":null,"abstract":"<div><div>To overcome the limitations of insufficient performance enhancement, poor construction quality control and low efficiency associated with existing reinforcement methods for shield tunnels, a prefabricated UHPC panel (PUP) reinforcement method is proposed, along with a novel joint for panel connection, referred to as the assembled bolt-plate joint (ABPJ). A series of flexural tests are conducted to systematically reveal the effects of load type and key design parameters on the mechanical behaviour of the ABPJ, and corresponding optimization strategies are proposed. A refined finite element (FE) model for the interlayer composite damage behaviour of bonded reinforced segmental structure was developed based on coupled CZM (Cohesive Zone Model)-XFEM (eXtended Finite Element Method) method, clarifying the influence of the ABPJ on the load-bearing performance and damage mechanisms of the reinforced structure. The results show that the technical framework of the prefabricated UHPC panel reinforcement method encompasses three key aspects: standardized design, industrialized production, and prefabricated construction. The flexural failure of the ABPJ is governed by the formation of plastic hinges, which may develop either at the groove wall or at the joint interface. The former is caused by the combined effects of flexural tension and the weakening of the cross-section due to grooving, while the latter results from insufficient stiffness of the connecting plate. To ensure adequate bidirectional flexural stiffness, the ABPJ connecting plate thickness should not be less than 20 mm. Under axial compression combined with positive bending, the development of gaps at the ABPJ compromises the structural integrity, leading to interlayer composite failure characterized by adhesive layer cracking and interfacial debonding, and a reduction in load-bearing capacity of approximately 25 % for the reinforced structure. Under axial compression combined with negative bending, the high level of axial force helps maintain compression at the joint interface, making the presence of the ABPJ have a negligible effect on the reinforcement effectiveness.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"168 ","pages":"Article 107108"},"PeriodicalIF":7.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108587","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 new method to determine the surrounding rock pressure in twin tunnels with small clear spacing","authors":"Zhiyu Tian ,&nbsp;Chuan He ,&nbsp;Guowen Xu ,&nbsp;Guojin Lin ,&nbsp;YueHeng Shu ,&nbsp;Jun Wang ,&nbsp;Liang Nie","doi":"10.1016/j.tust.2025.107106","DOIUrl":"10.1016/j.tust.2025.107106","url":null,"abstract":"<div><div>This study introduces a new method for calculating the surrounding rock pressure of twin-tunnels with small clear spacing under various working conditions. The proposed method unifies the calculation approaches for surrounding rock pressure under different working conditions into a single framework. A comparison is made between the new method and the standard recommended methods, and the installation procedures for field monitoring instruments of surrounding rock pressure are standardized. Laboratory experiments are conducted to correct the monitored values of surrounding rock pressure in the field. Additionally, the active–passive load separation method is employed to extract the active load component from the measured pressure values. The results show that the surrounding rock pressure calculated using the new method aligns more closely with actual engineering conditions. The variation trends and absolute magnitudes of surrounding rock pressure are smaller than those obtained using the standard methods. The corrected surrounding rock pressure values are closer to the true surrounding rock pressure. By comparing the active load derived from the measured values with the calculated surrounding rock pressure, the comparison results become more accurate. Furthermore, a three-way comparison among the calculated values from the new method, the standard recommended values, and the field-measured values confirms the correctness of the new method and its rationality and applicability in practical engineering projects.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"168 ","pages":"Article 107106"},"PeriodicalIF":7.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109103","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":"Drone-based photogrammetry and virtual reality: technological alternatives for tunnel inspection","authors":"Leandro Silva de Assis,&nbsp;Bernardo Lopes Poncetti,&nbsp;Lucas Bellini Machado,&nbsp;Marcos Massao Futai","doi":"10.1016/j.tust.2025.107094","DOIUrl":"10.1016/j.tust.2025.107094","url":null,"abstract":"<div><div>This study presents a comparative analysis of tunnel inspection methodologies, emphasizing the effectiveness of Virtual Reality (VR) inspection using drone-based 3D photogrammetric models in contrast to traditional visual inspection (TVI). The experiment was conducted in a 750-meter-long engineered concrete road tunnel in São Paulo, Brazil. The research involved fixing 139 synthetic pathology indicators inside the tunnel to standardize the assessments, and the photogrammetric model was compared to the Sacannig terrestrial laser – TLS 3D model, to evaluate the geometry quality. Results revealed that TVI achieved a precision of just 18% and an accuracy of 63%, highlighting significant subjectivity and inconsistency in manual inspections. In contrast, the VR method demonstrated an improved precision of 73% and an accuracy of 98%, with a reduction in the false discovery rate from 32% to 1%. The drone inspection was completed in approximately 35 min, significantly reducing inspection time compared to the two hours required for TVI. Furthermore, the photogrammetric approach proved better than Terrestrial Laser Scanning (TLS) in terms of occlusion reduction and visual realism, although TLS maintained advantages in data processing speed and accuracy. To the best of our knowledge, this is the first replicable study that directly compares VR-based inspection with TVI using a standardized dataset of synthetic tunnel pathologies, providing a robust ground-truth benchmark for future research. These findings underscore the potential of drone-based photogrammetry combined with Virtual Reality to enhance the efficiency, reliability, and scalability of tunnel inspections.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"168 ","pages":"Article 107094"},"PeriodicalIF":7.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109252","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":"Friction stabilizers for rock bursts hazard mitigation in deep mines’ environments","authors":"Witold Pytel ,&nbsp;Bogumiła Pałac-Walko ,&nbsp;Jan Butra ,&nbsp;Piotr Mertuszka","doi":"10.1016/j.tust.2025.107096","DOIUrl":"10.1016/j.tust.2025.107096","url":null,"abstract":"<div><div>As underground mining reaches deeper and deeper deposits of useful materials, it is associated with an increasing threat from rock outbursts, which have become the greatest challenge in securing the excavations with appropriate ground support system. Also, despite decades of research, effective management of rock burst still continues to be a formidable challenge in underground operations. Therefore, selecting and designing the most suitable support systems are crucial for securing underground openings, limiting their deformation and ensuring their long-term stability. In a such situation, energy absorbing rock bolt is today recognized as an important support element in deep mines around the world. Ground support system composed on energy absorbing elements is able to utilize the general principle of ground control in rock burst prone conditions. This consists in the dynamic energy transfer on the yielding support system to facilitate absorption and controlled deformation of rock mass.</div><div>The paper shows that in the case where stiff rock bolts cannot provide stability of excavation walls (i.e., the load is much higher than the bolt’s capacity), energy-absorbing yield ground support can successfully confine or even eliminate the risk of failure by allowing controlled movement of the expelled blocks of rock. The developed 2-dimensional model of rock bursts from an underground excavation’s sidewalls, based on the LEM (Limit Equilibrium Method), is relatively simple and sufficiently general analytical approach for formulating practical conclusions and recommendations with respect to selecting the best methods of ground support, particularly in the geological and mining conditions of deep mines. Presented herein model may be applied to continuous types of rocks as well as to rock mass characterized by more than one joint/discontinuity system. Also, the rock heterogeneity within sidewalls does not disturb the theoretical background of the developed models however it does require an additional analytical work to be done. The main contribution of this paper is the development of an algorithm for quantitatively tracking rock burst phenomena as a function of time (acceleration, velocity, and displacement of expelled rocks) as well as indicating the required ground support reinforcement. The advantages of the method are demonstrated using two types of energy-absorbing yield rock bolts: Split Sets and the new CTw twisted rock bolts. It is accepted that the so-called critical depth, at which the force unbalance can overcome the rock’s mass resistance, is the most important reference parameter for indication a rock burst high potential. The critical depth value under actual mining/geological conditions may be determined based on the obtained diagrams, not attached to the paper.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"168 ","pages":"Article 107096"},"PeriodicalIF":7.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109106","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":"Experimental study on the hardening behavior of compacted cohesive soil and its rapid evaluation method","authors":"Gongyun Xu,&nbsp;Yong Fang,&nbsp;Zetong Zhang,&nbsp;Yifan Jiang,&nbsp;Yuxiang Yao,&nbsp;Kaichen Ying,&nbsp;Bin Zhuo","doi":"10.1016/j.tust.2025.107109","DOIUrl":"10.1016/j.tust.2025.107109","url":null,"abstract":"<div><div>Shield tunnelling cutterheads are prone to mud cake formation in cohesive strata, which significantly reduces tunnelling efficiency. Current research on mud cake formation and risk prediction primarily focuses on adhesion behavior and largely overlooks the evaluation of the degree of mud cake hardening. Investigating the hardening behavior of cohesive soil under pressure is crucial to elucidate the development process of shield clogging and improve the methodology for assessing clogging risk. In this study, a Shore durometer is proposed for rapid assessment of the hardening level of compacted cohesive soil. The effects of clay mineral composition, initial water content, and pressure on the compaction characteristics, Shore hardness, and unconfined compression strength (UCS) of soil are systematically analyzed using two manually prepared cohesive soil samples: Sample I (illite-dominant) and Sample M (montmorillonite-dominant). The results indicate that under pressure, the dry density and UCS increased more significantly in Sample I than in Sample M due to efficient pore water drainage. The initial water content and compaction pressure jointly determine the peak UCS, with both dry density and UCS reaching their maxima at the plastic limit. Although low-plasticity muck exhibits low adhesion, it compacts and hardens easily under high pressure. Therefore, shield clogging risk assessment should comprehensively consider both adhesion and compaction properties. Shore hardness in low-hardness regions is affected by the puncture effect, whereas data distortion limitations became dominant in high-hardness regions. Overall, Shore hardness effectively reflects the degree of hardening of compacted cohesive soil and can serve as a rapid indicator for shield clogging assessment.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"168 ","pages":"Article 107109"},"PeriodicalIF":7.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109102","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":"Data-driven evacuation time prediction for train passengers under floods: A differentiated deep learning framework","authors":"Xiaoxia Yang ,&nbsp;Chuang Shao ,&nbsp;Chuan-Zhi (Thomas) Xie ,&nbsp;Yuanlei Kang","doi":"10.1016/j.tust.2025.107068","DOIUrl":"10.1016/j.tust.2025.107068","url":null,"abstract":"<div><div>Predicting the evacuation time of subway train passengers is a key issue in flood disaster prevention and emergency management. However, traditional experiments are time-consuming and costly, failing to meet real-time requirements. To address this issue, this paper proposes a differentiated deep learning framework named DCBAK, which integrates an advanced differentiated creative search (DCS), convolutional neural networks, bidirectional long short-term memory networks, attention mechanisms, and kernel density estimation. The designed DCS is innovatively applied to optimize hyperparameters in the integrated network, and an enhanced fitness calculation method is proposed to improve the quality of time prediction. Kernel density estimation synthesizes the contributions and distribution characteristics of point prediction results, enhancing the smoothness and credibility of evacuation time prediction results. The introduction of SHAP structure increases the transparency and interpretability of prediction results. Data on train passenger evacuation collected by PathFinder are used to demonstrate the effectiveness of the proposed method. The results show that: (1) The proposed DCBAK approach achieves a high coefficient of determination above 0.90 and even up to 0.99, indicating a high degree of data fitting; (2) Under a 95% confidence interval, the prediction interval coverage probability of the evacuation time reaches 0.95, accurately explaining the uncertainty range of results; (3) The most significant factor affecting the evacuation time of train passengers in flood disasters is the train stopping scenario. This study emphasizes the potential of differentiated deep learning networks in addressing the challenge of rapid evacuation time prediction in emergency evacuation management.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"167 ","pages":"Article 107068"},"PeriodicalIF":7.4,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145093880","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":"Distributed temperature sensor model for linear heat detection in tunnel fires","authors":"Jakub Bielawski ,&nbsp;Dia Luan ,&nbsp;Xiaoning Zhang ,&nbsp;Weikang Xie ,&nbsp;Xinyan Huang ,&nbsp;Wojciech Węgrzyński","doi":"10.1016/j.tust.2025.107092","DOIUrl":"10.1016/j.tust.2025.107092","url":null,"abstract":"<div><div>This study proposes a method for implementing distributed temperature sensing systems in tunnel fire simulations. A review of the investigations was conducted, and previous research on linear heat detection was examined. The characteristics and operational parameters of a complete DTS-based LHD system in a road tunnel are presented. A heat transfer model of the DTS sensor cable for CFD modelling was developed based on experiments in the standardised EN 54–5 wind tunnel for testing heat sensors. Based on the data analysis, substitute physical properties of the sensor cable were selected for the heat transfer model to allow implementation of the DTS model in CFD. Concurrently, an RTI value of 90 (m/s)^1/2 was approximated to compare the model with the response-time model commonly used in fire engineering analyses. To validate the model, two full-scale fire tests were carried out in a road tunnel in Świnoujście, Poland, and CFD numerical simulations were performed with the proposed DTS model. The relative error of detection time prediction was within 3% for the case with low velocity, and successfully predicted no detection in the case with high velocity (&gt;1 m/s). The developed model allows to tracking temperature changes of the DTS sensor cable with satisfactory precision and can be applied in various tunnel fire analyses.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"167 ","pages":"Article 107092"},"PeriodicalIF":7.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145093881","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":"Moisture migration within the melting laps during construction controls frost heaving damage of lining in permafrost tunnels","authors":"Hailiang Jia ,&nbsp;Kangyong Xiao ,&nbsp;Yibo Hao ,&nbsp;Long Jin ,&nbsp;Yao Wei ,&nbsp;Xianjun Tan","doi":"10.1016/j.tust.2025.107107","DOIUrl":"10.1016/j.tust.2025.107107","url":null,"abstract":"<div><div>Frost heaving damage is a typical hazard in tunnels constructed in cold regions, among which frost heave induced by the freezing expansion of surrounding rock stands as one of the primary factors leading to stress concentration and even cracking failure in lining structures. Under the influence of construction thermal disturbances, the thawing of surrounding rock is accompanied by moisture redistribution, where the characteristics of water distribution play a critical role in governing frost heave. This study establishes a thermal-hydro-mechanical (THM) coupled model for melting laps, validated through the Jiangluling Tunnel case. Integrating laboratory freezing tests on gravel soils with numerical simulations, we investigate moisture migration impacts on lining frost heaving damage under construction thermal disturbance and operational refreezing. The results indicate: (1) The numerical simulations align closely with field monitoring data, validating the accuracy of the model for this project. (2) Pore ice formation without moisture migration generates negligible frost heave pressure. (3) Moisture redistribution during construction creates water-enriched zones at tunnel flanks, causing tensile stress concentration (peak 6.008 MPa) at lining sidewalls. (4) The tensile stress at the inner walls of the lining initially increases gradually, then rises rapidly, and finally stabilizes. Mechanistic analysis reveals that moisture redistribution within the melting laps under construction thermal disturbance establishes essential material precondition for frost heave. During operational phases, initial frost heave develops in surrounding rocks, which subsequently subjected to seasonal freeze–thaw cycles triggers cumulative frost heave effects. Consequently, maximum tensile stress in lining structures demonstrates progressive annual escalation. This research provides theoretical basis for frost-resistant lining design in permafrost tunnels.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"167 ","pages":"Article 107107"},"PeriodicalIF":7.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145093875","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":"Optimization on escape exit selection for personnel in highway tunnel fires","authors":"Jinghong Wang,&nbsp;Jintao Li,&nbsp;Hongcheng Lu,&nbsp;Siming Wang,&nbsp;Ran Ye,&nbsp;Jialin Wu","doi":"10.1016/j.tust.2025.107081","DOIUrl":"10.1016/j.tust.2025.107081","url":null,"abstract":"<div><div>Pedestrian evacuation during fires has become a critical concern due to the increasing frequency of tunnel fire accidents in recent years. Existing research faces limitations in dynamically adjusting evacuation paths to respond to changing fire source locations. This study employs FDS and MassMotion software to investigate the impact of various fire source locations on pedestrian exit choices and evacuation efficiency in tunnels. A standard tunnel model was developed based on regulatory designs. Fire and evacuation simulations were conducted. Evacuation efficiency metrics were refined, and K-means clustering and polynomial regression methods were applied to determine optimal exit selection strategies for different fire source positions. The results indicate that, in a tunnel fire, adjusting the distribution of pedestrians between the nearest adjacent escape exits upstream of the fire source is crucial to improving overall evacuation efficiency. The optimal evacuation strategy involves directing all pedestrians located between the nearest and the adjacent upstream exits to the adjacent exit when the fire source is 0–75 m from the nearest upstream exit. Pedestrians situated between the adjacent and the farthest upstream exits should proceed to the farthest exit. When the fire source is 175–250 m from the nearest upstream exit, evacuation selection points should be set 50 m upstream of the nearest exit and 70 m upstream of the adjacent exit to effectively direct pedestrians toward exits on both sides. This research contributes to enhanced safety and improved evacuation efficiency, providing valuable insights for emergency management.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"167 ","pages":"Article 107081"},"PeriodicalIF":7.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145093882","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}