A tunnel-group metro station built in rock site is composed of a group of tunnels.Different tunnels and their interconnections can show inconsistent responses during an earthquake.This study investigates the dynamic r...A tunnel-group metro station built in rock site is composed of a group of tunnels.Different tunnels and their interconnections can show inconsistent responses during an earthquake.This study investigates the dynamic responses of such a metro station in a rock site,by shaking table tests.The lining structures of each tunnel and surrounding rock are modeled based on the similitude law;foam concrete and gypsum are used to model the ground-structure system,keeping relative stiffness consistent with that of the prototype.A series of harmonic waves are employed as excitations,input along the transverse and longitudinal direction of the shaking table.The discrepant responses caused by the structural irregularities are revealed by measurement of acceleration and strain of the model.Site characteristics are identified by the transfer function method in white noise cases.The test results show that the acceleration response and strain response of the structure are controlled by the ground.In particular,the acceleration amplification effect at the opening section of the station hall is more significant than that at the standard section under transverse excitation;the amplification effect of the structural opening is insignificant under longitudinal excitation.展开更多
Quality assurance and maintenance play a crucial role in engineering construction,as they have a significant impact on project safety.One common issue in concrete structures is the presence of defects.To enhance the a...Quality assurance and maintenance play a crucial role in engineering construction,as they have a significant impact on project safety.One common issue in concrete structures is the presence of defects.To enhance the automation level of concrete defect repairs,this study proposes a computer vision-based robotic system,which is based on three-dimensional(3D)printing technology to repair defects.This system integrates multiple sensors such as light detection and ranging(LiDAR)and camera.LiDAR is utilized to model concrete pipelines and obtain geometric parameters regarding their appearance.Additionally,a convolutional neural network(CNN)is employed with a depth camera to locate defects in concrete structures.Furthermore,a method for coordinate transformation is presented to convert the obtained coordinates into executable ones for a robotic arm.Finally,the feasibility of this concrete defect repair method is validated through simulation and experiments.展开更多
基金supported by the National Key R&D Program of China(No.2021YFE0114100)the National Natural Science Foundation of China(Grant Nos.U1934210 and 52061135112).
文摘A tunnel-group metro station built in rock site is composed of a group of tunnels.Different tunnels and their interconnections can show inconsistent responses during an earthquake.This study investigates the dynamic responses of such a metro station in a rock site,by shaking table tests.The lining structures of each tunnel and surrounding rock are modeled based on the similitude law;foam concrete and gypsum are used to model the ground-structure system,keeping relative stiffness consistent with that of the prototype.A series of harmonic waves are employed as excitations,input along the transverse and longitudinal direction of the shaking table.The discrepant responses caused by the structural irregularities are revealed by measurement of acceleration and strain of the model.Site characteristics are identified by the transfer function method in white noise cases.The test results show that the acceleration response and strain response of the structure are controlled by the ground.In particular,the acceleration amplification effect at the opening section of the station hall is more significant than that at the standard section under transverse excitation;the amplification effect of the structural opening is insignificant under longitudinal excitation.
基金This research was funded by the Ministry of Science and Technology of China(No.2021YFE0114100)the Science and Technology Commission of Shanghai Municipality(No.21DZ1203505)the Top Discipline Plan of Shanghai Universities-Class I.
文摘Quality assurance and maintenance play a crucial role in engineering construction,as they have a significant impact on project safety.One common issue in concrete structures is the presence of defects.To enhance the automation level of concrete defect repairs,this study proposes a computer vision-based robotic system,which is based on three-dimensional(3D)printing technology to repair defects.This system integrates multiple sensors such as light detection and ranging(LiDAR)and camera.LiDAR is utilized to model concrete pipelines and obtain geometric parameters regarding their appearance.Additionally,a convolutional neural network(CNN)is employed with a depth camera to locate defects in concrete structures.Furthermore,a method for coordinate transformation is presented to convert the obtained coordinates into executable ones for a robotic arm.Finally,the feasibility of this concrete defect repair method is validated through simulation and experiments.
