The investigation of supporting pressure is of great significance to the design of underground structures.Based on the kinematical approach of limit analysis,an improved failure mechanism is proposed,and the supportin...The investigation of supporting pressure is of great significance to the design of underground structures.Based on the kinematical approach of limit analysis,an improved failure mechanism is proposed,and the supporting pressure is investigated for deep buried cavity.Three failure mechanisms are first introduced according to the existing failure mechanisms of geotechnical structures of limit analysis.A comparison with respect to the optimal failure mechanisms and the upper bound solutions provided among these three mechanisms are then conducted in an attempt to obtain the improved failure mechanism.The results provided by the improved failure mechanism are in good agreement with those by the existing method,the numerical solution and field monitoring,which demonstrates that the proposed failure mechanism is effective for the upper bound analysis of supporting pressure.展开更多
Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the e...Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the effect of the blast vibration, a possible collapse would occur at a certain region between the concealed karst cave and the excavated cavity. This paper aims to study the roof collapse of a deep buried cavity induced by a concealed karst cave base on a two-dimensional failure mechanism by using upper bound theorem. The failure mechanism is constituted by arbitrary curves which is similar to the collapse observed in an actual cavity excavation. The shape and range of the collapse block is determined by virtual work equation in conjunction with variational approach. The results obtained by the presented approach are approximate with the numerical results provided by finite difference code, which indicates that the proposed method in this work is valid.展开更多
The development of a“two birds with one stone”strategy for capturing pollutant molecules and incorporating new functions provides a promising solution for sustainability.In this work,we designed an unprecedented dee...The development of a“two birds with one stone”strategy for capturing pollutant molecules and incorporating new functions provides a promising solution for sustainability.In this work,we designed an unprecedented deep-cavity aluminum–organic macrocycle to trap dye molecules and enhance non-linear optical performance.Using long building blocks and inorganic aluminum ions at the midriff,we successfully isolated a deep-cavity(1.8 nm)macrocycle,with a deeper cavity than classic pure organic macrocycles,such as crown ether and calixarenes.We report the accurate locking of the HAO7 dye molecule in the deep-cavity macrocycle and reveal its trapping mechanism at the molecular level for the first time.The combined host–vip compound AlOC-136-HAO7 displays altered physical properties,such as a decreased optical band gap and increased proton conductivity but also exhibits enhanced third-order non-linear optical(NLO)properties.Combined with theoretical calculations,we confirmed that the enhancement was attributed to abundant host–vip interactions and the vip-to-vip charge transfer.Our findings provide a strategy for isolating deep-cavity macrocycles and further demonstrate their enormous potential for capturing contaminants and forming valuable materials.展开更多
基金Project(51674115)supported by the National Natural Science Foundation of ChinaProject(51434006)supported by the Key Program of the National Natural Science Foundation of ChinaProject(2015JJ4024)supported by the Natural Science Foundation of Hunan Province,China
文摘The investigation of supporting pressure is of great significance to the design of underground structures.Based on the kinematical approach of limit analysis,an improved failure mechanism is proposed,and the supporting pressure is investigated for deep buried cavity.Three failure mechanisms are first introduced according to the existing failure mechanisms of geotechnical structures of limit analysis.A comparison with respect to the optimal failure mechanisms and the upper bound solutions provided among these three mechanisms are then conducted in an attempt to obtain the improved failure mechanism.The results provided by the improved failure mechanism are in good agreement with those by the existing method,the numerical solution and field monitoring,which demonstrates that the proposed failure mechanism is effective for the upper bound analysis of supporting pressure.
基金Projects(51878074,51678071)supported by the National Natural Science Foundation of China
文摘Reliable prediction of the potential collapse region of rock mass is a key challenge for deep underground cavity excavation, especially if a concealed karst cave is located above the excavated cavity. Because of the effect of the blast vibration, a possible collapse would occur at a certain region between the concealed karst cave and the excavated cavity. This paper aims to study the roof collapse of a deep buried cavity induced by a concealed karst cave base on a two-dimensional failure mechanism by using upper bound theorem. The failure mechanism is constituted by arbitrary curves which is similar to the collapse observed in an actual cavity excavation. The shape and range of the collapse block is determined by virtual work equation in conjunction with variational approach. The results obtained by the presented approach are approximate with the numerical results provided by finite difference code, which indicates that the proposed method in this work is valid.
基金supported by the National Natural Science Foundation of China(22371278,U23A2095,and 92061104)Natural Science Foundation of Fujian Province(2021J06035)Youth Innovation Promotion Association Chinese Academy of Sciences(Y2021081).
文摘The development of a“two birds with one stone”strategy for capturing pollutant molecules and incorporating new functions provides a promising solution for sustainability.In this work,we designed an unprecedented deep-cavity aluminum–organic macrocycle to trap dye molecules and enhance non-linear optical performance.Using long building blocks and inorganic aluminum ions at the midriff,we successfully isolated a deep-cavity(1.8 nm)macrocycle,with a deeper cavity than classic pure organic macrocycles,such as crown ether and calixarenes.We report the accurate locking of the HAO7 dye molecule in the deep-cavity macrocycle and reveal its trapping mechanism at the molecular level for the first time.The combined host–vip compound AlOC-136-HAO7 displays altered physical properties,such as a decreased optical band gap and increased proton conductivity but also exhibits enhanced third-order non-linear optical(NLO)properties.Combined with theoretical calculations,we confirmed that the enhancement was attributed to abundant host–vip interactions and the vip-to-vip charge transfer.Our findings provide a strategy for isolating deep-cavity macrocycles and further demonstrate their enormous potential for capturing contaminants and forming valuable materials.
