With the increase in the number and scale of tunnel projects in China in recent years,the comprehensive management for quality inspection and monitoring measurement in the tunnel construction process is receiving more...With the increase in the number and scale of tunnel projects in China in recent years,the comprehensive management for quality inspection and monitoring measurement in the tunnel construction process is receiving more and more attention.Based on this,this paper analyzes the comprehensive management of quality inspection and monitoring during tunnel construction to ensure the quality of tunnel construction.展开更多
The biggest environmental problem caused by the construction of tunnels adjacent to high-rise buildings is the settlement of buildings.The paper analyzes the influence of tunnel excavation on the deformation of the su...The biggest environmental problem caused by the construction of tunnels adjacent to high-rise buildings is the settlement of buildings.The paper analyzes the influence of tunnel excavation on the deformation of the superstructure and the deformation mode of the superstructure.It introduces the indicators and standards for the construction control of tunnel adjacent to the building at home and abroad.Combined with the Yuzhong tunnel project under construction in Chongqing,the main monitoring indicators and control standards of the Yuzhong Tunnel passing through the main buildings are given after comprehensive analysis and considerations,which provide a reference for the deformation control indicators of similar urban traffic tunnels adjacent to high-rise buildings.展开更多
Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the ass...Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the assumption of linear small deformation,a mathematical model of the relationship between ground deformation and construction parameters is set up.The principle and method of optimization for estimating ground deformation is studied.The actual measured data are compared with the results of theoretical analysis in a case.Considering different ground formations in different construction sites with different adverse effects on surface and underground structures,the ground surface deformations caused by shield tunneling is an aimed topic in this paper.The contributions and research implications are the revealed relationships between the ground deformation and the shield tunneling parameters during construction.展开更多
This article analyzes the application strategies of shotcrete anchor support technology using a highway bridge-tunnel construction project as an example.The article covers various strategies,including support plan for...This article analyzes the application strategies of shotcrete anchor support technology using a highway bridge-tunnel construction project as an example.The article covers various strategies,including support plan formulation,mortar shotcrete anchor construction,grid steel frame construction,steel mesh construction,and concrete support construction.This analysis aims to provide a guideline for those interested in applying this technology and improving the quality and safety of highway bridges and tunnels construction.展开更多
In this study,full-scale fire experiments were conducted in a hydropower station to investigate smoke propagation during tunnel construction.The flame height,smoke temperature and stratification,smoke descent and spre...In this study,full-scale fire experiments were conducted in a hydropower station to investigate smoke propagation during tunnel construction.The flame height,smoke temperature and stratification,smoke descent and spread velocity were analyzed via measurements and on-site observations.The initial combustion stage was largely affected by ignition source during tunnel construction for diesel pool fire,and the average flame height in the fully developed stage could reach 1.4-2.1 m in experimental fire scenarios.The gradient of the smoke temperature evolution near the fire was the opposite for the upstream and downstream regions.The longitudinal temperature distribution was concentrated in a small range at the heights of the smoke layer,and gradually decreased by air entrainment as the height decreased,while further increasing in the lower half of the tunnel height in the near-fire region under heat radiation from the fire source.Moreover,distinct and stable smoke stratification formed during the fully developed combustion stage,and the smoke layer interface was at approximately half the tunnel height.Smoke descent was aggravated in the decay stage of combustion,and the fire risk remained high after the fully developed period.The smoke front spread velocity was empirically determined for the full-scale tunnel fire scenarios.Conclusions from full-scale experiments can support smoke control design and on-site fire emergency response plans for hydropower stations.展开更多
In the process of tunnel construction,if large-deformation occurs in high geostress soft rock,it will likely cause geological disasters.This situation will not only seriously affect the smooth progress of tunnel const...In the process of tunnel construction,if large-deformation occurs in high geostress soft rock,it will likely cause geological disasters.This situation will not only seriously affect the smooth progress of tunnel construction,but also cause serious safety threat to the construction personnel.Therefore,with the continuous growth in the number and scale of tunnel construction in recent years,the construction technology for high geostress soft rock with large-deformation has begun to receive more and more attention from the society.Based on this,this paper takes an actual project as an example to analyze the specific application of the technology in order to improve the construction effect and avoid the damage caused by the large-deformation of the high geostress soft rock.展开更多
In the construction of a soft rock tunnel,it is critical to accurately estimate the pre-stressed anchor support parameters for surrounding rock reinforcement;otherwise,engineering disasters may occur.This paper presen...In the construction of a soft rock tunnel,it is critical to accurately estimate the pre-stressed anchor support parameters for surrounding rock reinforcement;otherwise,engineering disasters may occur.This paper presents a support parameter selection method that aims to allow deformation as a control objective,which was applied to the tunnel located in Muzailing Highway,Min County,Dingxi City,Gansu Province,China.Through theoretical analysis,we have identified five factors that influence pre-stressing anchorages.The selection of mechanical parameters for the rock mass was carried out using an inverse analysis method.Compared with the measured data,the maximum displacement error of the numerical simulation results was only 0.07 m.The length of anchor cable,circumferential spacing of anchor cable,longitudinal spacing,and pre-stress index are adopted as the input parameters for the support vector machine neural network model based on particle swarm optimization(PSO-LSSVM).Besides,the vault subsidence and the maximum deformation of surrounding rock are considered as output values(performance indices).The goodness of fit between the predicted values and the simulated values exceeds 0.9.Finally,all support parameters within the acceptable deformation range are calculated.The optimal support variables are derived by considering the construction cost and duration.The field application results show that it is feasible to construct the sample database utilizing the numerical simulation approach by taking the displacement as the control target and using the neural network to specify the appropriate support parameters.展开更多
With the coordinated development of social economy and technology today,various advanced construction techniques and well-established management measures have begun to be widely used in coal-tunnel construction.Howeve...With the coordinated development of social economy and technology today,various advanced construction techniques and well-established management measures have begun to be widely used in coal-tunnel construction.However,in the construction process of low-gas tunnels,it will also cause a certain degree of adverse impact on the construction quality and safety due to the lack of technical experience and management experience to a certain extent.Based on this,this paper takes the actual tunnel project of a coal mine as an example to analyze the main construction technology and safety management measures of low-gas tunnels,so as to provide guarantee for the quality and safety of such tunnel construction.展开更多
Large cross-section tunnel construction induces ground surface settlements, potentially endangering both subterranean projects and nearby above-ground structures. A novel tunnel construction method, known as the suspe...Large cross-section tunnel construction induces ground surface settlements, potentially endangering both subterranean projects and nearby above-ground structures. A novel tunnel construction method, known as the suspension method,is introduced in this paper to mitigate surface settlement. The suspension method employs vertical tie rods to establish a structural connection between the initial tunnel support system and the surface steel beam, thereby exerting effective control settlements. To analyze the performance of the proposed method, systematic numerical simulations were conducted based on the practical engineering of Harbin Subway Line 3. The surface settlement and vault settlement characteristics during construction are investigated. The results show a gradual increment in both surface and vault settlement throughout the construction process, culminating in a stabilized state upon the completion of construction.In addition, compared to the double-side drift method and the Cross Diaphragm Method(CRD) method, the suspension method can obviously reduce the surface settlement and vault settlement. Moreover, the surface settlements and the axial force of tie rods were continuously monitored during the construction process at the trial tunnel block.These specific monitoring measurements are illustrated in comparison to numerical analysis results. The monitored results show great agreement with the numerical predictions, confirming the success of the project. This research can serve as a valuable practical reference for similar projects, offering insights and guidance for addressing ground surface settlements and enhancing construction safety in the domain of large cross-section tunneling.展开更多
This study integrates different machine learning(ML) methods and 5-fold cross-validation(CV) method to estimate the ground maximal surface settlement(MSS) induced by tunneling.We further investigate the applicability ...This study integrates different machine learning(ML) methods and 5-fold cross-validation(CV) method to estimate the ground maximal surface settlement(MSS) induced by tunneling.We further investigate the applicability of artificial intelligent(AI) based prediction through a comparative study of two tunnelling datasets with different sizes and features.Four different ML approaches,including support vector machine(SVM),random forest(RF),back-propagation neural network(BPNN),and deep neural network(DNN),are utilized.Two techniques,i.e.particle swarm optimization(PSO) and grid search(GS)methods,are adopted for hyperparameter optimization.To assess the reliability and efficiency of the predictions,three performance evaluation indicators,including the mean absolute error(MAE),root mean square error(RMSE),and Pearson correlation coefficient(R),are calculated.Our results indicate that proposed models can accurately and efficiently predict the settlement,while the RF model outperforms the other three methods on both datasets.The difference in model performance on two datasets(Datasets A and B) reveals the importance of data quality and quantity.Sensitivity analysis indicates that Dataset A is more significantly affected by geological conditions,while geometric characteristics play a more dominant role on Dataset B.展开更多
Freeze-sealing pipe roof method is applied in the Gongbei tunnel,which causes the ground surface uplift induced by frost heave.A frost heaving prediction approach based on the coefficient of cold expansion is proposed...Freeze-sealing pipe roof method is applied in the Gongbei tunnel,which causes the ground surface uplift induced by frost heave.A frost heaving prediction approach based on the coefficient of cold expansion is proposed to simulate the ground deformation of the Gongbei tunnel.The coefficient of cold expansion in the model and the frost heaving rate from the frost heave test under the hydration condition can achieve a good correspondence making the calculation result closer to the actual engineering.The ground surface uplift along the lateral and longitudinal direction are respectively analyzed and compared with the field measured data to validate the model.The results show that a good agreement between the frost heaving prediction model and the field measured data verifies the rationality and applicability of the proposed model.The maximum uplift of the Gongbei tunnel appears at the center of the model,gradually decreasing along with the lateral and longitudinal directions.The curve in the lateral direction presents a normal distribution due to the influence of the constraint of two sides,while the one along the lateral direction shapes like a parabola with the opening downward due to the temperature field distribution.The model provides a reference for frost heaving engineering calculation.展开更多
Forced ventilation is typically used in the construction of tunnels since it is an economical method to provide high amounts of fresh air.Air velocity and pollutant concentration near the work face are determined by t...Forced ventilation is typically used in the construction of tunnels since it is an economical method to provide high amounts of fresh air.Air velocity and pollutant concentration near the work face are determined by the ventilation arrangement.In the study,field measurement of air velocity was performed,and computational fluid dynamics(CFD)models were constructed to investigate airflow near the work face and predict the gas distribution in a gas tunnel construction.The effects of the distance between the air duct exit and the work face(L_(1))were evaluated by analyzing the flow field and pollutant concentration.The evaluation shows that the ventilation efficiency improves if L_(1) does not exceed 15 m in a road tunnel with full-face excavation.With respect to a road tunnel with benching excavation,the effects of bench length(L_(2))are analyzed,and the results of the analysis indicate that ventilation efficiency is optimal when L_(2)=5 m and L_(2)=10 m and the air-duct diameter corresponds to 1.6 m.The CFD results fit the field measurement significantly well,and the current ventilation system in the construction exhibits a relatively high efficiency.The findings of the study aid practitioners in optimizing ventilation efficiency.展开更多
This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining.The composite lining was formed by mining outside and shield tunne...This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining.The composite lining was formed by mining outside and shield tunnelling inside with backfill in between.Finite element method was conducted to analyse the axial forces and bending moment for voids of different diameters at different positions.The results show that the axial forces in the transverse section increase near the crown and then invert and decrease on the left and right sides with an increase in the void centre angle(β)measured from the vertical axis.The increase in void diameter(d<300 mm)induces an increase in the axial force on the left and right sides when β=45°and 90°,while it decreases near the crown and invert.The occurrence of voids leads to an increase in the bending moment in the entire segment section with an angle β.展开更多
文摘With the increase in the number and scale of tunnel projects in China in recent years,the comprehensive management for quality inspection and monitoring measurement in the tunnel construction process is receiving more and more attention.Based on this,this paper analyzes the comprehensive management of quality inspection and monitoring during tunnel construction to ensure the quality of tunnel construction.
基金National Key R&D Program of China Special Funding(2017YFC0805305)National Natural Science Foundation of China(41601574)Chinese Academy of Engineering Institute-Local Cooperation Project(2019-CQ-ZD-4)。
文摘The biggest environmental problem caused by the construction of tunnels adjacent to high-rise buildings is the settlement of buildings.The paper analyzes the influence of tunnel excavation on the deformation of the superstructure and the deformation mode of the superstructure.It introduces the indicators and standards for the construction control of tunnel adjacent to the building at home and abroad.Combined with the Yuzhong tunnel project under construction in Chongqing,the main monitoring indicators and control standards of the Yuzhong Tunnel passing through the main buildings are given after comprehensive analysis and considerations,which provide a reference for the deformation control indicators of similar urban traffic tunnels adjacent to high-rise buildings.
文摘Through the systematic analysis of the ground settlement generated by the process of shield tunneling,the relationships between ground deformation and construction parameters are studied in this paper.Based on the assumption of linear small deformation,a mathematical model of the relationship between ground deformation and construction parameters is set up.The principle and method of optimization for estimating ground deformation is studied.The actual measured data are compared with the results of theoretical analysis in a case.Considering different ground formations in different construction sites with different adverse effects on surface and underground structures,the ground surface deformations caused by shield tunneling is an aimed topic in this paper.The contributions and research implications are the revealed relationships between the ground deformation and the shield tunneling parameters during construction.
文摘This article analyzes the application strategies of shotcrete anchor support technology using a highway bridge-tunnel construction project as an example.The article covers various strategies,including support plan formulation,mortar shotcrete anchor construction,grid steel frame construction,steel mesh construction,and concrete support construction.This analysis aims to provide a guideline for those interested in applying this technology and improving the quality and safety of highway bridges and tunnels construction.
基金supported by the National Natural Science Foundation of China(52104198,72091512)the Science and Technology Project of the Fire and Rescue Department Ministry of Emergency Management(2021XFZD02).
文摘In this study,full-scale fire experiments were conducted in a hydropower station to investigate smoke propagation during tunnel construction.The flame height,smoke temperature and stratification,smoke descent and spread velocity were analyzed via measurements and on-site observations.The initial combustion stage was largely affected by ignition source during tunnel construction for diesel pool fire,and the average flame height in the fully developed stage could reach 1.4-2.1 m in experimental fire scenarios.The gradient of the smoke temperature evolution near the fire was the opposite for the upstream and downstream regions.The longitudinal temperature distribution was concentrated in a small range at the heights of the smoke layer,and gradually decreased by air entrainment as the height decreased,while further increasing in the lower half of the tunnel height in the near-fire region under heat radiation from the fire source.Moreover,distinct and stable smoke stratification formed during the fully developed combustion stage,and the smoke layer interface was at approximately half the tunnel height.Smoke descent was aggravated in the decay stage of combustion,and the fire risk remained high after the fully developed period.The smoke front spread velocity was empirically determined for the full-scale tunnel fire scenarios.Conclusions from full-scale experiments can support smoke control design and on-site fire emergency response plans for hydropower stations.
文摘In the process of tunnel construction,if large-deformation occurs in high geostress soft rock,it will likely cause geological disasters.This situation will not only seriously affect the smooth progress of tunnel construction,but also cause serious safety threat to the construction personnel.Therefore,with the continuous growth in the number and scale of tunnel construction in recent years,the construction technology for high geostress soft rock with large-deformation has begun to receive more and more attention from the society.Based on this,this paper takes an actual project as an example to analyze the specific application of the technology in order to improve the construction effect and avoid the damage caused by the large-deformation of the high geostress soft rock.
基金supported by the Open Fund of State Key Laboratory of High speed Railway Track Technology(2022YJ127-1)National Natural Science Foundation of China(52104125,41941018)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(2022JQ-304)the Young Elite Scientists Sponsorship Program by CAST(No.2021QNRC001)。
文摘In the construction of a soft rock tunnel,it is critical to accurately estimate the pre-stressed anchor support parameters for surrounding rock reinforcement;otherwise,engineering disasters may occur.This paper presents a support parameter selection method that aims to allow deformation as a control objective,which was applied to the tunnel located in Muzailing Highway,Min County,Dingxi City,Gansu Province,China.Through theoretical analysis,we have identified five factors that influence pre-stressing anchorages.The selection of mechanical parameters for the rock mass was carried out using an inverse analysis method.Compared with the measured data,the maximum displacement error of the numerical simulation results was only 0.07 m.The length of anchor cable,circumferential spacing of anchor cable,longitudinal spacing,and pre-stress index are adopted as the input parameters for the support vector machine neural network model based on particle swarm optimization(PSO-LSSVM).Besides,the vault subsidence and the maximum deformation of surrounding rock are considered as output values(performance indices).The goodness of fit between the predicted values and the simulated values exceeds 0.9.Finally,all support parameters within the acceptable deformation range are calculated.The optimal support variables are derived by considering the construction cost and duration.The field application results show that it is feasible to construct the sample database utilizing the numerical simulation approach by taking the displacement as the control target and using the neural network to specify the appropriate support parameters.
文摘With the coordinated development of social economy and technology today,various advanced construction techniques and well-established management measures have begun to be widely used in coal-tunnel construction.However,in the construction process of low-gas tunnels,it will also cause a certain degree of adverse impact on the construction quality and safety due to the lack of technical experience and management experience to a certain extent.Based on this,this paper takes the actual tunnel project of a coal mine as an example to analyze the main construction technology and safety management measures of low-gas tunnels,so as to provide guarantee for the quality and safety of such tunnel construction.
基金supported by the Fundamental Research Funds for the Central Universities(2023JBZD004)the National Natural Science Foundation of China(U2034204,52078031)the Science and Technology Development Project of cccC Harbin Metro Investment and Construction Co.,Ltd.(ZJHD-FW-2018-01-086).
文摘Large cross-section tunnel construction induces ground surface settlements, potentially endangering both subterranean projects and nearby above-ground structures. A novel tunnel construction method, known as the suspension method,is introduced in this paper to mitigate surface settlement. The suspension method employs vertical tie rods to establish a structural connection between the initial tunnel support system and the surface steel beam, thereby exerting effective control settlements. To analyze the performance of the proposed method, systematic numerical simulations were conducted based on the practical engineering of Harbin Subway Line 3. The surface settlement and vault settlement characteristics during construction are investigated. The results show a gradual increment in both surface and vault settlement throughout the construction process, culminating in a stabilized state upon the completion of construction.In addition, compared to the double-side drift method and the Cross Diaphragm Method(CRD) method, the suspension method can obviously reduce the surface settlement and vault settlement. Moreover, the surface settlements and the axial force of tie rods were continuously monitored during the construction process at the trial tunnel block.These specific monitoring measurements are illustrated in comparison to numerical analysis results. The monitored results show great agreement with the numerical predictions, confirming the success of the project. This research can serve as a valuable practical reference for similar projects, offering insights and guidance for addressing ground surface settlements and enhancing construction safety in the domain of large cross-section tunneling.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)-Discovery Grant(Grant No.RGPIN-2019-06471)the McMaster University Engineering Life Event Fund。
文摘This study integrates different machine learning(ML) methods and 5-fold cross-validation(CV) method to estimate the ground maximal surface settlement(MSS) induced by tunneling.We further investigate the applicability of artificial intelligent(AI) based prediction through a comparative study of two tunnelling datasets with different sizes and features.Four different ML approaches,including support vector machine(SVM),random forest(RF),back-propagation neural network(BPNN),and deep neural network(DNN),are utilized.Two techniques,i.e.particle swarm optimization(PSO) and grid search(GS)methods,are adopted for hyperparameter optimization.To assess the reliability and efficiency of the predictions,three performance evaluation indicators,including the mean absolute error(MAE),root mean square error(RMSE),and Pearson correlation coefficient(R),are calculated.Our results indicate that proposed models can accurately and efficiently predict the settlement,while the RF model outperforms the other three methods on both datasets.The difference in model performance on two datasets(Datasets A and B) reveals the importance of data quality and quantity.Sensitivity analysis indicates that Dataset A is more significantly affected by geological conditions,while geometric characteristics play a more dominant role on Dataset B.
基金supported by the financial support from National Natural Science Foundation of China(No.51478340)Natural Science Foundation of Jiangsu Province(No.BK20200707)+4 种基金The Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.20KJB560029)China Postdoctoral Science Foundation(No.2020M671670)Key Laboratory of Soft Soils and Geoenvironmental Engineering(Zhejiang University)Ministry of Education(No.2020P04)the support above is gratefully acknowledged.
文摘Freeze-sealing pipe roof method is applied in the Gongbei tunnel,which causes the ground surface uplift induced by frost heave.A frost heaving prediction approach based on the coefficient of cold expansion is proposed to simulate the ground deformation of the Gongbei tunnel.The coefficient of cold expansion in the model and the frost heaving rate from the frost heave test under the hydration condition can achieve a good correspondence making the calculation result closer to the actual engineering.The ground surface uplift along the lateral and longitudinal direction are respectively analyzed and compared with the field measured data to validate the model.The results show that a good agreement between the frost heaving prediction model and the field measured data verifies the rationality and applicability of the proposed model.The maximum uplift of the Gongbei tunnel appears at the center of the model,gradually decreasing along with the lateral and longitudinal directions.The curve in the lateral direction presents a normal distribution due to the influence of the constraint of two sides,while the one along the lateral direction shapes like a parabola with the opening downward due to the temperature field distribution.The model provides a reference for frost heaving engineering calculation.
基金supported by the National Key Research and Development Program(2016YFC0802205),Chinathe National Natural Science Foundation of China(No:64051578460),Chinathe National Key Research and Development Program of China(2016YFC0802200),China.
文摘Forced ventilation is typically used in the construction of tunnels since it is an economical method to provide high amounts of fresh air.Air velocity and pollutant concentration near the work face are determined by the ventilation arrangement.In the study,field measurement of air velocity was performed,and computational fluid dynamics(CFD)models were constructed to investigate airflow near the work face and predict the gas distribution in a gas tunnel construction.The effects of the distance between the air duct exit and the work face(L_(1))were evaluated by analyzing the flow field and pollutant concentration.The evaluation shows that the ventilation efficiency improves if L_(1) does not exceed 15 m in a road tunnel with full-face excavation.With respect to a road tunnel with benching excavation,the effects of bench length(L_(2))are analyzed,and the results of the analysis indicate that ventilation efficiency is optimal when L_(2)=5 m and L_(2)=10 m and the air-duct diameter corresponds to 1.6 m.The CFD results fit the field measurement significantly well,and the current ventilation system in the construction exhibits a relatively high efficiency.The findings of the study aid practitioners in optimizing ventilation efficiency.
基金funded by the Pearl River Talent Recruitment Program(Grant No.2019CX01G338)Guangdong Province and the Research Funding of Shantou University for New Faculty Member(Grant No.NTF19024-2019).
文摘This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining.The composite lining was formed by mining outside and shield tunnelling inside with backfill in between.Finite element method was conducted to analyse the axial forces and bending moment for voids of different diameters at different positions.The results show that the axial forces in the transverse section increase near the crown and then invert and decrease on the left and right sides with an increase in the void centre angle(β)measured from the vertical axis.The increase in void diameter(d<300 mm)induces an increase in the axial force on the left and right sides when β=45°and 90°,while it decreases near the crown and invert.The occurrence of voids leads to an increase in the bending moment in the entire segment section with an angle β.
