The quasi-rectangular tunnel represents a novel cross-section design,intended to supersede the traditional circular and rectangular tunnel formats.Due to the limited capacity of the tunnel vault to withstand vertical ...The quasi-rectangular tunnel represents a novel cross-section design,intended to supersede the traditional circular and rectangular tunnel formats.Due to the limited capacity of the tunnel vault to withstand vertical loads,an interior column is often installed at the center to enhance its load-bearing capacity.This study aims to develop a hyperstatic reaction method(HRM)for the analysis of deformation and structural integrity in this specific tunnel type.The computational model is validated through comparison with the corresponding finite element method(FEM)analysis.Following comprehensive validation,an ensemble machine learning(ML)model is proposed,using numerical benchmark data,to facilitate real-time design and optimization.Subsequently,three widely used ensemble models,i.e.random forest(RF),gradient boosting decision tree(GBDT),and extreme gradient boosting(XGBoost)are compared to identify the most efficient ML model for replacing the HRM model in the design optimization process.The performance metrics,such as the coefficient of determination R2 of about 0.999 and the mean absolute percentage error(MAPE)of about 1%,indicate that XGBoost outperforms the others,exhibiting excellent agreement with the HRM analysis.Additionally,the model demonstrates high computational efficiency,with prediction times measured in seconds.Finally,the HRM-XGBoost model is integrated with the well-known particle swarm optimization(PSO)for the real-time design optimization of quasi-rectangular tunnels,both with and without the interior column.A feature importance assessment is conducted to evaluate the sensitivity of design input features,enabling the selection of the most critical features for the optimization task.展开更多
The infrastructure in the urban core area is becoming increasingly dense,leading to restrictions on intensive development;however,there is a lack of adequate research on the structural mechanics of quasi-rectangular p...The infrastructure in the urban core area is becoming increasingly dense,leading to restrictions on intensive development;however,there is a lack of adequate research on the structural mechanics of quasi-rectangular pipe jacking tunnels.This paper presents an experimental investigation that was conducted to analyze the impact of ground surcharge on the structural behavior of a quasi-rectangular tunnel located at Jing’an Temple station of Shanghai Rail Transit Line 14.The experimental setup included a scaled-down model of a quasi-rectangular tunnel,which was considered to be typical of underground structures.A series of tests were carried out by applying varying surcharge loads and eccentricities on the ground surface located above the tunnel.The tunnel structure’s response was monitored and analyzed through the use of earth pressure gauges,displacement sensors,and strain gauges.The experimental results revealed that ground surcharge on existing tunnels is mainly influenced by eccentricity and depth,with distinct effects at zero eccentricity and increasing eccentricity.Shallow tunnel burial depths intensify the impact of ground surcharge on the tunnel structure.展开更多
The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combi...The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.展开更多
In-situ enlargement of super-large-span tunnels can intensify excavation-induced unloading in the surrounding rock,increasing deformation demand and failure risk during construction.This study combines laboratory mode...In-situ enlargement of super-large-span tunnels can intensify excavation-induced unloading in the surrounding rock,increasing deformation demand and failure risk during construction.This study combines laboratory model tests with FLAC3D simulations to evaluate the stabilizing role of prestressed anchor cables and to establish an energy-balance framework for support optimization.Comparative model tests of existing and enlarged tunnel sections,with and without anchors,show that reinforcement increases load-carrying capacity,reduces displacement,and confines damage to more localized zones.The numerical simulations reproduce displacement fields,shear-strain localization,and plastic-zone evolution with good agreement against the experimental observations.The energy framework is implemented in the in-situ simulations by quantifying unloading-related energy release in the rock mass and reinforcement work contributed by the anchors,and by introducing an energy release–reinforcement ratio as a stability indicator.Parametric analyses indicate that anchor length,spacing,and prestress influence stability in a nonlinear manner,with diminishing returns once reinforcement extends beyond the mechanically dominant deformation zone.An efficient parameter window is identified that improves deformation and yielding control while avoiding unnecessary reinforcement.The results provide an energy-consistent and design-oriented basis for prestressed anchorage selection in large-span tunnel expansion.展开更多
Urban tunnels are often built in multiples,yet the influence of surface structures on their support demands is frequently overlooked,highlighting the need for refined design under realistic loading.This study addresse...Urban tunnels are often built in multiples,yet the influence of surface structures on their support demands is frequently overlooked,highlighting the need for refined design under realistic loading.This study addresses this gap by examining the response of a uniformly loaded strip footing above twin horseshoe tunnels with structural linings.A non-dimensional Footing Stability Improvement Factor(I_(f)),defined as the ratio of ultimate bearing capacity with and without lining to that of a footing on intact rock—is evaluated using adaptive finite element limit analysis.The effects of normalized vertical depth of tunnel,normalised horizontal spacing of tunnel,and lining-thickness factor are examined,providing key insights into foundation-tunnel interaction and support optimization.This study finds that,for unlined twin tunnels,footing-tunnel interaction becomes negligible when embedment exceeds four times of footing widths and tunnel spacing surpasses eleven times of footing widths,beyond which additional support is unnecessary.For lined tunnels,the tunnel-lining thickness required to maintain footing stability equivalent to that on intact rock decreases rapidly with embedment depth.At a tunnel spacing equal to onehalf of the footing width,the critical lining-thickness ratio is about six percent of the footing width at a tunnel depth of half the footing width,reducing to approximately five,four,and three percent at depths of one,one-and-a-half,and two footing widths,and asymptotically approaching nearly one percent for embedment depths exceeding two-and-a-half footing widths.Additionally,rock mass parameters exhibit minimal impact(±2%)on I_(f).The results show that failure mechanisms in footing-tunnel systems are primarily governed by tunnels-positional parmeters,and lining thickness.The study presents a mechanistic framework that delineates the critical depth-spacing-thickness regimes controlling twin-tunnel behavior,providing engineers with clear design boundaries and performance-based lining guidelines to improve the stability of both tunnels and overlying foundations.展开更多
Geological prospecting and the identification of adverse geological features are essential in tunnel construction,providing critical information to ensure safety and guide engineering decisions.As tunnel projects exte...Geological prospecting and the identification of adverse geological features are essential in tunnel construction,providing critical information to ensure safety and guide engineering decisions.As tunnel projects extend into deeper and more mountainous terrains,engineers face increasingly complex geological conditions,including high water pressure,intense geo-stress,elevated geothermal gradients,and active fault zones.These conditions pose substantial risks such as high-pressure water inrush,largescale collapses,and tunnel boring machine(TBM)blockages.Addressing these challenges requires advanced detection technologies capable of long-distance,high-precision,and intelligent assessments of adverse geology.This paper presents a comprehensive review of recent advancements in tunnel geological ahead prospecting methods.It summarizes the fundamental principles,technical maturity,key challenges,development trends,and real-world applications of various detection techniques.Airborne and semi-airborne geophysical methods enable large-scale reconnaissance for initial surveys in complex terrain.Tunnel-and borehole-based approaches offer high-resolution detection during excavation,including seismic ahead prospecting(SAP),TBM rock-breaking source seismic methods,fulltime-domain tunnel induced polarization(TIP),borehole electrical resistivity,and ground penetrating radar(GPR).To address scenarios involving multiple,coexisting adverse geologies,intelligent inversion and geological identification methods have been developed based on multi-source data fusion and artificial intelligence(AI)techniques.Overall,these advances significantly improve detection range,resolution,and geological characterization capabilities.The methods demonstrate strong adaptability to complex environments and provide reliable subsurface information,supporting safer and more efficient tunnel construction.展开更多
Residents living near drill-and-blast tunnels often experience disturbances from blasting operations.This motivates us to investigate the characteristics of airblasts and resulting noise through on-site monitoring at ...Residents living near drill-and-blast tunnels often experience disturbances from blasting operations.This motivates us to investigate the characteristics of airblasts and resulting noise through on-site monitoring at three tunnels.The research focuses on both the temporal evolution and spatial propagation of airblasts.Temporal analysis,including peak overpressure(POp),positive duration(PD),and Fourier main frequency(MF),emphasizes the relationship between airblast characteristics,blasting delays,and rock grade.It shows that airblast bandwidths are typically in the range of 3e200 Hz,with noise levels exceeding 130 dB,which is comparable to jet engines and rocket launch.Spatial propagation analysis reveals the impact of tunnel space on airblast propagation.Although POp and PD typically decrease with distance inside the tunnel,wave superposition can cause increased overpressure and prolonged durations at far-field distances(above 60 m kg^(-1/3)).Outside the tunnel,sound radiation was influenced by azimuth and was basically determined by sound power d an often-overlooked factor.To address the anisotropic propagation of airblasts,a predictive model was proposed for external noise levels,considering variables like distance,azimuth angle,initial sound power,and wave expansion.Validated by tests,this model successfully unifies data from three studies,helping to explain and predict airblast disturbances near tunnels.展开更多
The existing 2D settlement monitoring systems for utility tunnels are heavily reliant on manual interpretation of deformation data and empirical predictionmodels.Consequently,early anomalies(e.g.,minor cracks)are ofte...The existing 2D settlement monitoring systems for utility tunnels are heavily reliant on manual interpretation of deformation data and empirical predictionmodels.Consequently,early anomalies(e.g.,minor cracks)are often misjudged,and warnings lag by about 24 h without automated spatial localization.This study establishes a technical framework for requirements analysis,architectural design,and data-integration protocols.Revit parametric modelling is used to build a 3D tunnel model with structural elements,pipelines and 18 monitoring points(for displacement and joint width).Custom Revit API code integrated real-time sensor data into the BIM platform via an automated pipeline.The system achieved a spatial accuracy of±1 mm in locating deformation hotspots.Notifications are triggered within 10 s of anomaly detection,and the system renders 3D risk propagation paths in real-time.Realtime 3D visualization of risk propagation paths is also facilitated.The efficacy of the solution was validated in a Ningbo utility tunnel project,where it was demonstrated that it eliminates human-dependent judgment errors and reduces warning latency by 99.9%compared to conventional methods.The BIM-IoT integrated approach,which enables millimetre-level precision in risk identification and near-instantaneous response,establishes a new paradigm for intelligent infrastructure safety management.展开更多
The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,...The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.展开更多
Excessive blasting-induced vibration during drilling-and-blasting excavation of deep tunnels can trigger geological hazards and compromise the stability of both the rock mass and support structures.This study focused ...Excessive blasting-induced vibration during drilling-and-blasting excavation of deep tunnels can trigger geological hazards and compromise the stability of both the rock mass and support structures.This study focused on the deep double-line Sejila Mountain tunnel to systematically analyze the spatial response of blasting-induced vibration and to develop a prediction model through field tests and numerical simulations.The results revealed that the presence of a cross passage significantly altered propagation paths and the spatial distribution of blasting-induced vibration velocity.The peak particle velocity(PPV)at the cross-passage corner was amplified by approximately 1.92 times due to wave reflection and geometric focusing.Blasting-induced vibration waves attenuated non-uniformly across the tunnel cross-section,where PPV on the blast-face side was 1.54–6.56 times higher than that on the opposite side.We propose an improved PPV attenuation model that accounts for the propagation path effect.This model significantly improved fitting accuracy and resolved anomalous parameter(k and a)estimates in traditional equations,thereby improving prediction reliability.Furthermore,based on the observed spatial distribution of blasting-induced vibration,optimal monitoring point placement and targeted vibration control measures for tunnel blasting were discussed.These findings provide a scientific basis for designing blasting schemes and vibration mitigation strategies in deep tunnels.展开更多
Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On ...Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.展开更多
Cyperus esculentus(C.esculentus),a desert-adapted plant species with both ecological and economic value,has been widely cultivated in northern China's sandy regions.However,limited studies have investigated the pe...Cyperus esculentus(C.esculentus),a desert-adapted plant species with both ecological and economic value,has been widely cultivated in northern China's sandy regions.However,limited studies have investigated the performance of composite shelterbelts that integrate C.esculentus.This study systematically evaluated five shelterbelt models—Populus euphratica(P.euphratica),P.euphratica–C.esculentus composite,P.euphratica–nylon net–C.esculentus composite,Tamarix chinensis(T.chinensis),and T.chinensis–C.esculentus composite—using wind tunnel experiments and field observations.Sediment flux was measured at a normalized downwind distance(x/h)of 5,where x refers to the distance from the front edge(upwind side)of the shelterbelt for upwind measurements,and the distance from the rear edge(downwind side)for downwind measurements,and h represents the canopy height.Wind velocity was measured at x/h of–2,–1,1,2,3,5,and 7,and sand flux was measured at x/h=5,under initial wind velocities of 8.0 and 12.0 m/s.The results indicated that the P.euphratica–nylon net–C.esculentus composite was the most effective in reducing wind velocity,followed by the P.euphratica–C.esculentus composite.In contrast,the P.euphratica and T.chinensis exhibited relatively weaker wind reduction capabilities.Regarding sand flux,under moderate wind velocity(8.0 m/s),both the P.euphratica–C.esculentus composite and P.euphratica–nylon net–C.esculentus composite demonstrated the lowest sand flux values.However,under high wind velocity(12.0 m/s),the P.euphratica–nylon net–C.esculentus composite significantly outperformed the other shelterbelt models in sand retention,highlighting its superior windbreak and sand fixation efficacy.Field observations further validated the windbreak and sand fixation effects of C.esculentus.Comparisons between the bare sand plot and C.esculentus plot within protective forests demonstrated that planting C.esculentus can provide substantial ecological benefits in windbreak and sand-fixation.These findings,reinforced by field observations,strengthen the wind tunnel experiment results and highlight the critical role of C.esculentus in enhancing the performance of composite shelterbelts for desert ecological restoration.展开更多
Strong seismic excitation and fault dislocation are likely to occur simultaneously in high-intensity seismic zones,causing severe damage to tunnels crossing active fault zones.This paper aims to develop a novel analyt...Strong seismic excitation and fault dislocation are likely to occur simultaneously in high-intensity seismic zones,causing severe damage to tunnels crossing active fault zones.This paper aims to develop a novel analytical solution to determine the longitudinal mechanical responses of tunnels subjected to the combined effects of seismic waves and strike-slip faulting.Adopting the elastic springbeam model,the seismic waves are modelled as shear horizontal(SH)waves and the fault dislocation follows an S-shaped pattern;the superposition principle for free-fielddisplacements caused by both effects is assumed.In addition,the transmission and reflectionof seismic waves at the fault-rock geological interface and the tangential contact conditions at the tunnel-rock interface are considered.The analytical model is validated against numerical simulations,confirmingits accuracy in calculating tunnel responses.Moreover,a parametric study is conducted to evaluate the impact of key factors,including fault displacement,fault zone width,fault dip angle,earthquake frequency,rock conditions,tunnel lining stiffness,and tangential contact conditions,on tunnel responses.Compared with each effect alone,the combined effects of seismic waves and strike-slip faulting significantlychange the tunnel deformation and internal forces,leading to increased tunnel responses,especially within the fault zone and near the fault-rock interfaces.Depending on specificparameters,tunnel responses can be classifiedinto seismic-dominated,faulting-dominated,and seismic-faulting coupled responses on the basis of the relative contributions of each effect.The proposed analytical solution can be applied to quickly predict the longitudinal mechanical behaviour of tunnels under such combined effects in engineering applications.展开更多
3D laser scanning technology is widely used in underground openings for high-precision,rapid,and nondestructive structural evaluations.Segmenting large 3D point cloud datasets,particularly in coal mine roadways with m...3D laser scanning technology is widely used in underground openings for high-precision,rapid,and nondestructive structural evaluations.Segmenting large 3D point cloud datasets,particularly in coal mine roadways with multi-scale targets,remains challenging.This paper proposes an enhanced segmentation method integrating improved PointNet++with a coverage-voted strategy.The coverage-voted strategy reduces data while preserving multi-scale target topology.The segmentation is achieved using an enhanced PointNet++algorithm with a normalization preprocessing head,resulting in a 94%accuracy for common supporting components.Ablation experiments show that the preprocessing head and coverage strategies increase segmentation accuracy by 20%and 2%,respectively,and improve Intersection over Union(IoU)for bearing plate segmentation by 58%and 20%.The accuracy of the current pretraining segmentation model may be affected by variations in surface support components,but it can be readily enhanced through re-optimization with additional labeled point cloud data.This proposed method,combined with a previously developed machine learning model that links rock bolt load and the deformation field of its bearing plate,provides a robust technique for simultaneously measuring the load of multiple rock bolts in a single laser scan.展开更多
Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoret...Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.展开更多
Accurate and rapid recognition of weathering degree(WD)and groundwater condition(GC)is essential for evaluating rock mass quality and conducting stability analyses in underground engineering.Conventional WD and GC rec...Accurate and rapid recognition of weathering degree(WD)and groundwater condition(GC)is essential for evaluating rock mass quality and conducting stability analyses in underground engineering.Conventional WD and GC recognition methods often rely on subjective evaluation by field experts,supplemented by field sampling and laboratory testing.These methods are frequently complex and timeconsuming,making it challenging to meet the rapidly evolving demands of underground engineering.Therefore,this study proposes a rock non-geometric parameter classification network(RNPC-net)to rapidly achieve the recognition and mapping ofWD and GC of tunnel faces.The hybrid feature extraction module(HFEM)in RNPC-net can fully extract,fuse,and utilize multi-scale features of images,enhancing the network's classification performance.Moreover,the designed adaptive weighting auxiliary classifier(AC)helps the network learn features more efficiently.Experimental results show that RNPC-net achieved classification accuracies of 0.8756 and 0.8710 for WD and GC,respectively,representing an improvement of approximately 2%e10%compared to other methods.Both quantitative and qualitative experiments confirm the effectiveness and superiority of RNPC-net.Furthermore,for WD and GC mapping,RNPC-net outperformed other methods by achieving the highest mean intersection over union(mIOU)across most tunnel faces.The mapping results closely align with measurements provided by field experts.The application of WD and GC mapping results to the rock mass rating(RMR)system achieved a transition from conventional qualitative to quantitative evaluation.This advancement enables more accurate and reliable rock mass quality evaluations,particularly under critical conditions of RMR.展开更多
Although machine learning models have achieved high enough accuracy in predicting shield position deviations,their“black box”nature makes the prediction mechanisms and decision-making processes opaque,leading to wea...Although machine learning models have achieved high enough accuracy in predicting shield position deviations,their“black box”nature makes the prediction mechanisms and decision-making processes opaque,leading to weaker explanations and practicability.This study introduces a novel explainable deep learning framework comprising the Informer model with enhanced attention mechanisms(EAMInfor)and deep learning important features(DeepLIFT),aimed at improving the prediction accuracy of shield position deviations and providing interpretability for predictive results.The EAMInfor model attempts to integrate channel attention,spatial attention,and simple attention modules to improve the Informer model's performance.The framework is tested with the four different geological conditions datasets generated from the Xiamen metro line 3,China.Results show that the EAMInfor model outperforms the traditional Informer and comparison models.The analysis with the DeepLIFT method indicates that the push thrust of push cylinder and the earth chamber pressure are the most significant features,while the stroke length of the push cylinder demonstrated lower importance.Furthermore,the variation trends in the significance of data points within input sequences exhibit substantial differences between single and composite strata.This framework not only improves predictive accuracy but also strengthens the credibility and reliability of the results.展开更多
Tunneling nanotubes are crucial structures for cellular communication and are observed in a variety of cell types.Glial cells,the most abundant cells in the nervous system,play a vital role in intercellular signaling ...Tunneling nanotubes are crucial structures for cellular communication and are observed in a variety of cell types.Glial cells,the most abundant cells in the nervous system,play a vital role in intercellular signaling and can show abnormal activation under pathological conditions.Our bibliometric analysis indicated a substantial increase in research on tunneling nanotubes over the past two decades,highlighting their important role in cellular communication.This review focuses on the formation of tunneling nanotubes in various types of glial cells,including astrocytes,microglia,glioma cells,and Schwann cells,as well as their roles in cellular communication and cargo transport.We found that glial cells influence the stability of the neural system and play a role in nerve regeneration through tunneling nanotubes.Tunneling nanotubes facilitate the transmission and progression of diseases by transporting pathogens and harmful substances.However,they are also involved in alleviating cellular stress by removing toxins and delivering essential nutrients.Understanding the interactions between glial cells through tunneling nanotubes could provide valuable insights into the complex neural networks that govern brain function and responses to injury.展开更多
An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of a...An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of adverse geological conditions in deep-buried tunnel construction.The installation techniques for microseismic sensors were optimized by mounting sensors at bolt ends which significantly improves signal-to-noise ratio(SNR)and anti-interference capability compared to conventional borehole placement.Subsequently,a 3D wave velocity evolution model that incorporates construction-induced disturbances was established,enabling the first visualization of spatiotemporal variations in surrounding rock wave velocity.It finds significant wave velocity reduction near the tunnel face,with roof and floor damage zones extending 40–50 m;wave velocities approaching undisturbed levels at 15 m ahead of the working face and on the laterally undisturbed side;pronounced spatial asymmetry in wave velocity distribution—values on the left side exceed those on the right,with a clear stress concentration or transition zone located 10–15 m;and systematically lower velocities behind the face than in front,indicating asymmetric rock damage development.These results provide essential theoretical support and practical guidance for optimizing dynamic construction strategies,enabling real-time adjustment of support parameters,and establishing safety early warning systems in deep-buried tunnel engineering.展开更多
基金funded by the Hanoi University of Mining and Geology(Grant No.T23-44)The research is also funded by the German Research Foundation(DFG e Project number 518862444)in collaboration with the Vietnam National Foundation for Science and Technology Development(NAFOSTED)under grant number DFG.105e2022.03The third author was funded by the Postdoctoral Scholarship Program of the Vingroup Innovation Foundation(VINIF)(VINIF.2023.STS.15).
文摘The quasi-rectangular tunnel represents a novel cross-section design,intended to supersede the traditional circular and rectangular tunnel formats.Due to the limited capacity of the tunnel vault to withstand vertical loads,an interior column is often installed at the center to enhance its load-bearing capacity.This study aims to develop a hyperstatic reaction method(HRM)for the analysis of deformation and structural integrity in this specific tunnel type.The computational model is validated through comparison with the corresponding finite element method(FEM)analysis.Following comprehensive validation,an ensemble machine learning(ML)model is proposed,using numerical benchmark data,to facilitate real-time design and optimization.Subsequently,three widely used ensemble models,i.e.random forest(RF),gradient boosting decision tree(GBDT),and extreme gradient boosting(XGBoost)are compared to identify the most efficient ML model for replacing the HRM model in the design optimization process.The performance metrics,such as the coefficient of determination R2 of about 0.999 and the mean absolute percentage error(MAPE)of about 1%,indicate that XGBoost outperforms the others,exhibiting excellent agreement with the HRM analysis.Additionally,the model demonstrates high computational efficiency,with prediction times measured in seconds.Finally,the HRM-XGBoost model is integrated with the well-known particle swarm optimization(PSO)for the real-time design optimization of quasi-rectangular tunnels,both with and without the interior column.A feature importance assessment is conducted to evaluate the sensitivity of design input features,enabling the selection of the most critical features for the optimization task.
基金Financial support,jointly provided by the Ministry of Science and Technology of China(No.2021YFE0114100)the Federal Ministry of Education,Science,and Research(BMBWF)of Austria(No.CN11/2021)for the project“Intense Upgrades of the New Austrian Tunnelling Method(NATM)and Demonstration of its Applicability to High-Quality Urban Development”,is gratefully acknowledged+2 种基金the National Natural Science Foundation of China(Grant No.U1934210)the Science and Technology Commission of Shanghai Municipality(Nos.21DZ1203505,22DZ1203005,21DZ1202803,and 21DZ1202806)the Shanghai Rising-Star Program(No.22QB1405000)for their financial support of this work.
文摘The infrastructure in the urban core area is becoming increasingly dense,leading to restrictions on intensive development;however,there is a lack of adequate research on the structural mechanics of quasi-rectangular pipe jacking tunnels.This paper presents an experimental investigation that was conducted to analyze the impact of ground surcharge on the structural behavior of a quasi-rectangular tunnel located at Jing’an Temple station of Shanghai Rail Transit Line 14.The experimental setup included a scaled-down model of a quasi-rectangular tunnel,which was considered to be typical of underground structures.A series of tests were carried out by applying varying surcharge loads and eccentricities on the ground surface located above the tunnel.The tunnel structure’s response was monitored and analyzed through the use of earth pressure gauges,displacement sensors,and strain gauges.The experimental results revealed that ground surcharge on existing tunnels is mainly influenced by eccentricity and depth,with distinct effects at zero eccentricity and increasing eccentricity.Shallow tunnel burial depths intensify the impact of ground surcharge on the tunnel structure.
基金Guangzhou Metro Scientific Research Project(No.JT204-100111-23001)Chongqing Municipal Special Project for Technological Innovation and Application Development(No.CSTB2022TIAD-KPX0101)Science and Technology Research and Development Program of China State Railway Group Co.,Ltd.(No.N2023G045)。
文摘The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.
基金funded by the National Key R&D Program of China,China(No.2024YFF0507903)the National Key Research and Development Program of China(Grant No.2024YFF0507904)the National Natural Science Foundation of China,China(Grant No.52379114).These supports are gratefully acknowledged.
文摘In-situ enlargement of super-large-span tunnels can intensify excavation-induced unloading in the surrounding rock,increasing deformation demand and failure risk during construction.This study combines laboratory model tests with FLAC3D simulations to evaluate the stabilizing role of prestressed anchor cables and to establish an energy-balance framework for support optimization.Comparative model tests of existing and enlarged tunnel sections,with and without anchors,show that reinforcement increases load-carrying capacity,reduces displacement,and confines damage to more localized zones.The numerical simulations reproduce displacement fields,shear-strain localization,and plastic-zone evolution with good agreement against the experimental observations.The energy framework is implemented in the in-situ simulations by quantifying unloading-related energy release in the rock mass and reinforcement work contributed by the anchors,and by introducing an energy release–reinforcement ratio as a stability indicator.Parametric analyses indicate that anchor length,spacing,and prestress influence stability in a nonlinear manner,with diminishing returns once reinforcement extends beyond the mechanically dominant deformation zone.An efficient parameter window is identified that improves deformation and yielding control while avoiding unnecessary reinforcement.The results provide an energy-consistent and design-oriented basis for prestressed anchorage selection in large-span tunnel expansion.
文摘Urban tunnels are often built in multiples,yet the influence of surface structures on their support demands is frequently overlooked,highlighting the need for refined design under realistic loading.This study addresses this gap by examining the response of a uniformly loaded strip footing above twin horseshoe tunnels with structural linings.A non-dimensional Footing Stability Improvement Factor(I_(f)),defined as the ratio of ultimate bearing capacity with and without lining to that of a footing on intact rock—is evaluated using adaptive finite element limit analysis.The effects of normalized vertical depth of tunnel,normalised horizontal spacing of tunnel,and lining-thickness factor are examined,providing key insights into foundation-tunnel interaction and support optimization.This study finds that,for unlined twin tunnels,footing-tunnel interaction becomes negligible when embedment exceeds four times of footing widths and tunnel spacing surpasses eleven times of footing widths,beyond which additional support is unnecessary.For lined tunnels,the tunnel-lining thickness required to maintain footing stability equivalent to that on intact rock decreases rapidly with embedment depth.At a tunnel spacing equal to onehalf of the footing width,the critical lining-thickness ratio is about six percent of the footing width at a tunnel depth of half the footing width,reducing to approximately five,four,and three percent at depths of one,one-and-a-half,and two footing widths,and asymptotically approaching nearly one percent for embedment depths exceeding two-and-a-half footing widths.Additionally,rock mass parameters exhibit minimal impact(±2%)on I_(f).The results show that failure mechanisms in footing-tunnel systems are primarily governed by tunnels-positional parmeters,and lining thickness.The study presents a mechanistic framework that delineates the critical depth-spacing-thickness regimes controlling twin-tunnel behavior,providing engineers with clear design boundaries and performance-based lining guidelines to improve the stability of both tunnels and overlying foundations.
基金supported by the National Natural Science Foundation of China(Grant Nos.52021005,52325904,and 51991391)。
文摘Geological prospecting and the identification of adverse geological features are essential in tunnel construction,providing critical information to ensure safety and guide engineering decisions.As tunnel projects extend into deeper and more mountainous terrains,engineers face increasingly complex geological conditions,including high water pressure,intense geo-stress,elevated geothermal gradients,and active fault zones.These conditions pose substantial risks such as high-pressure water inrush,largescale collapses,and tunnel boring machine(TBM)blockages.Addressing these challenges requires advanced detection technologies capable of long-distance,high-precision,and intelligent assessments of adverse geology.This paper presents a comprehensive review of recent advancements in tunnel geological ahead prospecting methods.It summarizes the fundamental principles,technical maturity,key challenges,development trends,and real-world applications of various detection techniques.Airborne and semi-airborne geophysical methods enable large-scale reconnaissance for initial surveys in complex terrain.Tunnel-and borehole-based approaches offer high-resolution detection during excavation,including seismic ahead prospecting(SAP),TBM rock-breaking source seismic methods,fulltime-domain tunnel induced polarization(TIP),borehole electrical resistivity,and ground penetrating radar(GPR).To address scenarios involving multiple,coexisting adverse geologies,intelligent inversion and geological identification methods have been developed based on multi-source data fusion and artificial intelligence(AI)techniques.Overall,these advances significantly improve detection range,resolution,and geological characterization capabilities.The methods demonstrate strong adaptability to complex environments and provide reliable subsurface information,supporting safer and more efficient tunnel construction.
基金supported by the Shenzhen Stability Support Plan(Grant No.20231122095154003)National Natural Science Foundation of China(Grant Nos.51978671 and 52422807).
文摘Residents living near drill-and-blast tunnels often experience disturbances from blasting operations.This motivates us to investigate the characteristics of airblasts and resulting noise through on-site monitoring at three tunnels.The research focuses on both the temporal evolution and spatial propagation of airblasts.Temporal analysis,including peak overpressure(POp),positive duration(PD),and Fourier main frequency(MF),emphasizes the relationship between airblast characteristics,blasting delays,and rock grade.It shows that airblast bandwidths are typically in the range of 3e200 Hz,with noise levels exceeding 130 dB,which is comparable to jet engines and rocket launch.Spatial propagation analysis reveals the impact of tunnel space on airblast propagation.Although POp and PD typically decrease with distance inside the tunnel,wave superposition can cause increased overpressure and prolonged durations at far-field distances(above 60 m kg^(-1/3)).Outside the tunnel,sound radiation was influenced by azimuth and was basically determined by sound power d an often-overlooked factor.To address the anisotropic propagation of airblasts,a predictive model was proposed for external noise levels,considering variables like distance,azimuth angle,initial sound power,and wave expansion.Validated by tests,this model successfully unifies data from three studies,helping to explain and predict airblast disturbances near tunnels.
基金supported by the Scientific Research Projects of the Education Department of Zhejiang Province(Grant No.Y202454744)the Ningbo Public Welfare Science and Technology Project(Grant No.2024S077)+1 种基金International Sci-tech Cooperation Projects under the“Innovation Yongjiang 2035”Key R&D Programme(No.2024H019)the Ningbo Key R&D Program(Grant No.2024Z287).
文摘The existing 2D settlement monitoring systems for utility tunnels are heavily reliant on manual interpretation of deformation data and empirical predictionmodels.Consequently,early anomalies(e.g.,minor cracks)are often misjudged,and warnings lag by about 24 h without automated spatial localization.This study establishes a technical framework for requirements analysis,architectural design,and data-integration protocols.Revit parametric modelling is used to build a 3D tunnel model with structural elements,pipelines and 18 monitoring points(for displacement and joint width).Custom Revit API code integrated real-time sensor data into the BIM platform via an automated pipeline.The system achieved a spatial accuracy of±1 mm in locating deformation hotspots.Notifications are triggered within 10 s of anomaly detection,and the system renders 3D risk propagation paths in real-time.Realtime 3D visualization of risk propagation paths is also facilitated.The efficacy of the solution was validated in a Ningbo utility tunnel project,where it was demonstrated that it eliminates human-dependent judgment errors and reduces warning latency by 99.9%compared to conventional methods.The BIM-IoT integrated approach,which enables millimetre-level precision in risk identification and near-instantaneous response,establishes a new paradigm for intelligent infrastructure safety management.
基金funded by the National Natural Science Foundation of China(NSFC)under Grant No.52278415the National Key Research and Development Program of China under Grant No.2022YFC3801104+2 种基金Hebei Provincial Department of Education Project under Grant No.QN2025304the Innovation Fund Project of Hebei University of Engineering under Grant No.SJ2401002066the Sichuan Science and Technology Program under Grant No.2023YFS0407。
文摘The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.
基金financially supported by the National Natural Science Foundation of China(Nos.42577209 and U22A20239)the Key R&D Program of Hunan Province(No.2024WK2004)the Key Technologies for Accurate Diagnosis and Intelligent Prevention and Control of Slope Hazards in Open pit Mines,181 Major R&D projects of Metallurgical Corporation of China Ltd。
文摘Excessive blasting-induced vibration during drilling-and-blasting excavation of deep tunnels can trigger geological hazards and compromise the stability of both the rock mass and support structures.This study focused on the deep double-line Sejila Mountain tunnel to systematically analyze the spatial response of blasting-induced vibration and to develop a prediction model through field tests and numerical simulations.The results revealed that the presence of a cross passage significantly altered propagation paths and the spatial distribution of blasting-induced vibration velocity.The peak particle velocity(PPV)at the cross-passage corner was amplified by approximately 1.92 times due to wave reflection and geometric focusing.Blasting-induced vibration waves attenuated non-uniformly across the tunnel cross-section,where PPV on the blast-face side was 1.54–6.56 times higher than that on the opposite side.We propose an improved PPV attenuation model that accounts for the propagation path effect.This model significantly improved fitting accuracy and resolved anomalous parameter(k and a)estimates in traditional equations,thereby improving prediction reliability.Furthermore,based on the observed spatial distribution of blasting-induced vibration,optimal monitoring point placement and targeted vibration control measures for tunnel blasting were discussed.These findings provide a scientific basis for designing blasting schemes and vibration mitigation strategies in deep tunnels.
文摘Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.
基金supported by the Xinjiang Key Research and Development Programme Project(2022B02040-2)the Tianshan Yingcai Program of Xinjiang Uygur Autonomous Region(2024TSYCLJ0028).
文摘Cyperus esculentus(C.esculentus),a desert-adapted plant species with both ecological and economic value,has been widely cultivated in northern China's sandy regions.However,limited studies have investigated the performance of composite shelterbelts that integrate C.esculentus.This study systematically evaluated five shelterbelt models—Populus euphratica(P.euphratica),P.euphratica–C.esculentus composite,P.euphratica–nylon net–C.esculentus composite,Tamarix chinensis(T.chinensis),and T.chinensis–C.esculentus composite—using wind tunnel experiments and field observations.Sediment flux was measured at a normalized downwind distance(x/h)of 5,where x refers to the distance from the front edge(upwind side)of the shelterbelt for upwind measurements,and the distance from the rear edge(downwind side)for downwind measurements,and h represents the canopy height.Wind velocity was measured at x/h of–2,–1,1,2,3,5,and 7,and sand flux was measured at x/h=5,under initial wind velocities of 8.0 and 12.0 m/s.The results indicated that the P.euphratica–nylon net–C.esculentus composite was the most effective in reducing wind velocity,followed by the P.euphratica–C.esculentus composite.In contrast,the P.euphratica and T.chinensis exhibited relatively weaker wind reduction capabilities.Regarding sand flux,under moderate wind velocity(8.0 m/s),both the P.euphratica–C.esculentus composite and P.euphratica–nylon net–C.esculentus composite demonstrated the lowest sand flux values.However,under high wind velocity(12.0 m/s),the P.euphratica–nylon net–C.esculentus composite significantly outperformed the other shelterbelt models in sand retention,highlighting its superior windbreak and sand fixation efficacy.Field observations further validated the windbreak and sand fixation effects of C.esculentus.Comparisons between the bare sand plot and C.esculentus plot within protective forests demonstrated that planting C.esculentus can provide substantial ecological benefits in windbreak and sand-fixation.These findings,reinforced by field observations,strengthen the wind tunnel experiment results and highlight the critical role of C.esculentus in enhancing the performance of composite shelterbelts for desert ecological restoration.
基金supported by the National Natural Science Foundation of China(No.41941018)Shanghai Gaofeng Discipline Construction Funding.
文摘Strong seismic excitation and fault dislocation are likely to occur simultaneously in high-intensity seismic zones,causing severe damage to tunnels crossing active fault zones.This paper aims to develop a novel analytical solution to determine the longitudinal mechanical responses of tunnels subjected to the combined effects of seismic waves and strike-slip faulting.Adopting the elastic springbeam model,the seismic waves are modelled as shear horizontal(SH)waves and the fault dislocation follows an S-shaped pattern;the superposition principle for free-fielddisplacements caused by both effects is assumed.In addition,the transmission and reflectionof seismic waves at the fault-rock geological interface and the tangential contact conditions at the tunnel-rock interface are considered.The analytical model is validated against numerical simulations,confirmingits accuracy in calculating tunnel responses.Moreover,a parametric study is conducted to evaluate the impact of key factors,including fault displacement,fault zone width,fault dip angle,earthquake frequency,rock conditions,tunnel lining stiffness,and tangential contact conditions,on tunnel responses.Compared with each effect alone,the combined effects of seismic waves and strike-slip faulting significantlychange the tunnel deformation and internal forces,leading to increased tunnel responses,especially within the fault zone and near the fault-rock interfaces.Depending on specificparameters,tunnel responses can be classifiedinto seismic-dominated,faulting-dominated,and seismic-faulting coupled responses on the basis of the relative contributions of each effect.The proposed analytical solution can be applied to quickly predict the longitudinal mechanical behaviour of tunnels under such combined effects in engineering applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.52304139,52325403)the CCTEG Coal Mining Research Institute funding(Grant No.KCYJY-2024-MS-10).
文摘3D laser scanning technology is widely used in underground openings for high-precision,rapid,and nondestructive structural evaluations.Segmenting large 3D point cloud datasets,particularly in coal mine roadways with multi-scale targets,remains challenging.This paper proposes an enhanced segmentation method integrating improved PointNet++with a coverage-voted strategy.The coverage-voted strategy reduces data while preserving multi-scale target topology.The segmentation is achieved using an enhanced PointNet++algorithm with a normalization preprocessing head,resulting in a 94%accuracy for common supporting components.Ablation experiments show that the preprocessing head and coverage strategies increase segmentation accuracy by 20%and 2%,respectively,and improve Intersection over Union(IoU)for bearing plate segmentation by 58%and 20%.The accuracy of the current pretraining segmentation model may be affected by variations in surface support components,but it can be readily enhanced through re-optimization with additional labeled point cloud data.This proposed method,combined with a previously developed machine learning model that links rock bolt load and the deformation field of its bearing plate,provides a robust technique for simultaneously measuring the load of multiple rock bolts in a single laser scan.
基金support of the National Natural Science Foundation of China(Grant Nos.52179116 and 51991392)the support of Key Deployment Projects of Chinese Academy of Sciences(Grant No.ZDRW-ZS-2021-3).
文摘Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.
基金supported by the National Natural Science Foundation of China(Grant Nos.42077242 and 42171407)the Graduate Innovation Fund of Jilin University.
文摘Accurate and rapid recognition of weathering degree(WD)and groundwater condition(GC)is essential for evaluating rock mass quality and conducting stability analyses in underground engineering.Conventional WD and GC recognition methods often rely on subjective evaluation by field experts,supplemented by field sampling and laboratory testing.These methods are frequently complex and timeconsuming,making it challenging to meet the rapidly evolving demands of underground engineering.Therefore,this study proposes a rock non-geometric parameter classification network(RNPC-net)to rapidly achieve the recognition and mapping ofWD and GC of tunnel faces.The hybrid feature extraction module(HFEM)in RNPC-net can fully extract,fuse,and utilize multi-scale features of images,enhancing the network's classification performance.Moreover,the designed adaptive weighting auxiliary classifier(AC)helps the network learn features more efficiently.Experimental results show that RNPC-net achieved classification accuracies of 0.8756 and 0.8710 for WD and GC,respectively,representing an improvement of approximately 2%e10%compared to other methods.Both quantitative and qualitative experiments confirm the effectiveness and superiority of RNPC-net.Furthermore,for WD and GC mapping,RNPC-net outperformed other methods by achieving the highest mean intersection over union(mIOU)across most tunnel faces.The mapping results closely align with measurements provided by field experts.The application of WD and GC mapping results to the rock mass rating(RMR)system achieved a transition from conventional qualitative to quantitative evaluation.This advancement enables more accurate and reliable rock mass quality evaluations,particularly under critical conditions of RMR.
基金supported by the National Natural Science Foundation of China(Grant Nos.52378392,52408356)the Foal Eagle Program Youth Top-notch Talent Project of Fujian Province,China(Grant No.00387088).
文摘Although machine learning models have achieved high enough accuracy in predicting shield position deviations,their“black box”nature makes the prediction mechanisms and decision-making processes opaque,leading to weaker explanations and practicability.This study introduces a novel explainable deep learning framework comprising the Informer model with enhanced attention mechanisms(EAMInfor)and deep learning important features(DeepLIFT),aimed at improving the prediction accuracy of shield position deviations and providing interpretability for predictive results.The EAMInfor model attempts to integrate channel attention,spatial attention,and simple attention modules to improve the Informer model's performance.The framework is tested with the four different geological conditions datasets generated from the Xiamen metro line 3,China.Results show that the EAMInfor model outperforms the traditional Informer and comparison models.The analysis with the DeepLIFT method indicates that the push thrust of push cylinder and the earth chamber pressure are the most significant features,while the stroke length of the push cylinder demonstrated lower importance.Furthermore,the variation trends in the significance of data points within input sequences exhibit substantial differences between single and composite strata.This framework not only improves predictive accuracy but also strengthens the credibility and reliability of the results.
基金supported by the National Natural Science Foundation of China,No.82101115(to JY)the Wuhan University Independent Innovation Fund Youth Project,No.2042021kf0094(to JY).
文摘Tunneling nanotubes are crucial structures for cellular communication and are observed in a variety of cell types.Glial cells,the most abundant cells in the nervous system,play a vital role in intercellular signaling and can show abnormal activation under pathological conditions.Our bibliometric analysis indicated a substantial increase in research on tunneling nanotubes over the past two decades,highlighting their important role in cellular communication.This review focuses on the formation of tunneling nanotubes in various types of glial cells,including astrocytes,microglia,glioma cells,and Schwann cells,as well as their roles in cellular communication and cargo transport.We found that glial cells influence the stability of the neural system and play a role in nerve regeneration through tunneling nanotubes.Tunneling nanotubes facilitate the transmission and progression of diseases by transporting pathogens and harmful substances.However,they are also involved in alleviating cellular stress by removing toxins and delivering essential nutrients.Understanding the interactions between glial cells through tunneling nanotubes could provide valuable insights into the complex neural networks that govern brain function and responses to injury.
基金support of the National Natural Science Foundation of China(No.52274176)the Guangdong Province Key Areas R&D Program(No.2022B0101070001)+5 种基金Chongqing Elite Innovation and Entrepreneurship Leading talent Project(No.CQYC20220302517)the Chongqing Natural Science Foundation Innovation and Development Joint Fund(No.CSTB2022NSCQ-LZX0079)the National Key Research and Development Program Young Scientists Project(No.2022YFC2905700)the Chongqing Municipal Education Commission“Shuangcheng Economic Circle Construction in Chengdu-Chongqing Area”Science and Technology Innovation Project(No.KJCX2020031)the Fundamental Research Funds for the Central Universities(No.2024CDJGF-009)the Key Project for Technological Innovation and Application Development in Chongqing(No.CSTB2025TIAD-KPX0029).
文摘An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of adverse geological conditions in deep-buried tunnel construction.The installation techniques for microseismic sensors were optimized by mounting sensors at bolt ends which significantly improves signal-to-noise ratio(SNR)and anti-interference capability compared to conventional borehole placement.Subsequently,a 3D wave velocity evolution model that incorporates construction-induced disturbances was established,enabling the first visualization of spatiotemporal variations in surrounding rock wave velocity.It finds significant wave velocity reduction near the tunnel face,with roof and floor damage zones extending 40–50 m;wave velocities approaching undisturbed levels at 15 m ahead of the working face and on the laterally undisturbed side;pronounced spatial asymmetry in wave velocity distribution—values on the left side exceed those on the right,with a clear stress concentration or transition zone located 10–15 m;and systematically lower velocities behind the face than in front,indicating asymmetric rock damage development.These results provide essential theoretical support and practical guidance for optimizing dynamic construction strategies,enabling real-time adjustment of support parameters,and establishing safety early warning systems in deep-buried tunnel engineering.
