Rock masses are often exposed to dynamic loads such as earthquakes and mechanical disturbances in practical engineering scenarios.The existence of underground caverns and weak geological structures like columnar joint...Rock masses are often exposed to dynamic loads such as earthquakes and mechanical disturbances in practical engineering scenarios.The existence of underground caverns and weak geological structures like columnar jointed rock masses(CJRMs)and interlayer shear weakness zones(ISWZs)with inferior mechanical properties,significantly undermines the overall structural stability.To tackle the dynamic loading issues in the process of constructing subterranean caverns,a programmable modeling approach was utilized to reconstruct a large-scale underground cavern model incorporating ISWZs and columnar joints(CJs).By conducting dynamic simulations with varying load orientations,the analyses focused on the failure patterns,deformation characteristics,and acoustic emission activity within the caverns.Results revealed that the failure modes of the underground caverns under dynamic loading were predominantly tensile failures.Under X-direction loading,the failed elements were mainly distributed parallel to the CJs,while under Y-direction loading,they were distributed parallel to the transverse weak structural planes.Furthermore,the dynamic stability of the overall structure varied with the number of caverns.The dual-cavern model demonstrated the highest stability under X-direction loading,while the single-cavern model was the least stable.Under Y-direction loading,the cavern stability increased with the number of caverns.Importantly,different weak structures affected the dynamic response of caverns in different ways;the CJRMs were the primary contributors to structural failure,while ISWZs could mitigate the rock mass failure induced by CJs.The findings could offer valuable insights for the dynamic stability analysis of caverns containing CJRMs and ISWZs.展开更多
Mapping grasps from human to anthropomorphic robotic hands is an open issue in research,because the master hand and the slave hand have dissimilar kinematics.This paper proposes a hybrid mapping method to solve this p...Mapping grasps from human to anthropomorphic robotic hands is an open issue in research,because the master hand and the slave hand have dissimilar kinematics.This paper proposes a hybrid mapping method to solve this problem.In the proposed method,fingers in the master and the slave hands are divided into vital and synergic fingers according to their contribution to the grasping task.The tip of the vital finger of the master hand is first mapped to that of the slave hand while ensuring that both are in simultaneous contact with the object to be grasped.Following postural synergy theory,joints of the other synergic fingers of the slave hand are then used to generate an anthropomorphic grasping configuration according to the shape of the object to be grasped.Following this,a human-guided impedance controller is used to reduce the pre-grasping error and realize compliant interaction with the environment.The proposed hybrid mapping method can not only generate the posture of the humanoid envelope but can also carry out impedance-adaptive matching.It was evaluated using simulations and an experiment involving an anthropomorphic robotic slave hand.展开更多
With the acceleration of urbanization and the increasingly severe shortage of land resources in China,the development of underground space has emerged as a key strategy to alleviate urban development conflicts.It play...With the acceleration of urbanization and the increasingly severe shortage of land resources in China,the development of underground space has emerged as a key strategy to alleviate urban development conflicts.It plays a vital role in mitigat ing the“m etropolitan maladies”and optimizing the spatial layout of national territory.However,various issues in underground space development have become increasingly prominent,including inadequate planning systems,poor functional coordination,pronounced safe ty risks,and fragmented management mechanisms.Moreover,China's urban underground space development remains at an early stage,with a low degree of integration between above-ground and underground spaces,and a relatively weak resilient disaster preventi on system.This study analyzes key factors affecting the effectiveness of underground space development and proposes targeted strategies to enhance overall outcomes.These include improving institutional frameworks,promoting the integrated application of BIM and GIS technologies,constructing digital platforms,and facilitating green and low-carbon transitions.The research also offers theoretical insights to support the refinement of the Regulations on the Development and Utilization of Urban Underground Space.In the future,technical approaches can be further validated through integration with smart city pilot initiatives.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.42077251,41807269,and U1865203).
文摘Rock masses are often exposed to dynamic loads such as earthquakes and mechanical disturbances in practical engineering scenarios.The existence of underground caverns and weak geological structures like columnar jointed rock masses(CJRMs)and interlayer shear weakness zones(ISWZs)with inferior mechanical properties,significantly undermines the overall structural stability.To tackle the dynamic loading issues in the process of constructing subterranean caverns,a programmable modeling approach was utilized to reconstruct a large-scale underground cavern model incorporating ISWZs and columnar joints(CJs).By conducting dynamic simulations with varying load orientations,the analyses focused on the failure patterns,deformation characteristics,and acoustic emission activity within the caverns.Results revealed that the failure modes of the underground caverns under dynamic loading were predominantly tensile failures.Under X-direction loading,the failed elements were mainly distributed parallel to the CJs,while under Y-direction loading,they were distributed parallel to the transverse weak structural planes.Furthermore,the dynamic stability of the overall structure varied with the number of caverns.The dual-cavern model demonstrated the highest stability under X-direction loading,while the single-cavern model was the least stable.Under Y-direction loading,the cavern stability increased with the number of caverns.Importantly,different weak structures affected the dynamic response of caverns in different ways;the CJRMs were the primary contributors to structural failure,while ISWZs could mitigate the rock mass failure induced by CJs.The findings could offer valuable insights for the dynamic stability analysis of caverns containing CJRMs and ISWZs.
基金supported in part by the China National Key Research and Development Program under Grant no.2020YFC2007801in part by the National Natural Science Foundation of China under Grant no.U1813209.
文摘Mapping grasps from human to anthropomorphic robotic hands is an open issue in research,because the master hand and the slave hand have dissimilar kinematics.This paper proposes a hybrid mapping method to solve this problem.In the proposed method,fingers in the master and the slave hands are divided into vital and synergic fingers according to their contribution to the grasping task.The tip of the vital finger of the master hand is first mapped to that of the slave hand while ensuring that both are in simultaneous contact with the object to be grasped.Following postural synergy theory,joints of the other synergic fingers of the slave hand are then used to generate an anthropomorphic grasping configuration according to the shape of the object to be grasped.Following this,a human-guided impedance controller is used to reduce the pre-grasping error and realize compliant interaction with the environment.The proposed hybrid mapping method can not only generate the posture of the humanoid envelope but can also carry out impedance-adaptive matching.It was evaluated using simulations and an experiment involving an anthropomorphic robotic slave hand.
文摘With the acceleration of urbanization and the increasingly severe shortage of land resources in China,the development of underground space has emerged as a key strategy to alleviate urban development conflicts.It plays a vital role in mitigat ing the“m etropolitan maladies”and optimizing the spatial layout of national territory.However,various issues in underground space development have become increasingly prominent,including inadequate planning systems,poor functional coordination,pronounced safe ty risks,and fragmented management mechanisms.Moreover,China's urban underground space development remains at an early stage,with a low degree of integration between above-ground and underground spaces,and a relatively weak resilient disaster preventi on system.This study analyzes key factors affecting the effectiveness of underground space development and proposes targeted strategies to enhance overall outcomes.These include improving institutional frameworks,promoting the integrated application of BIM and GIS technologies,constructing digital platforms,and facilitating green and low-carbon transitions.The research also offers theoretical insights to support the refinement of the Regulations on the Development and Utilization of Urban Underground Space.In the future,technical approaches can be further validated through integration with smart city pilot initiatives.
