Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Ta...Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Taking two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first surveyed.The results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively large.Subsequently,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity method.It is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero linearly.For this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance factor.The evaluation results obtained by this method match well with actual observations.In addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst pits.The potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth.展开更多
Since the discovery of high temperature superconducting(HTS)materials in 1987,the performance of microwave filters such as insertion loss,selectivity,and out-band rejection has been significantly improved by utilizing...Since the discovery of high temperature superconducting(HTS)materials in 1987,the performance of microwave filters such as insertion loss,selectivity,and out-band rejection has been significantly improved by utilizing HTS films.Nowadays,HTS filters have been widely used in wireless communications,space exploration,satellite communications,and several other fields.HTS filters with a special performance,such as wideband,dual-band or multiband,frequency tunable,and high power-handling capability have been designed and fabricated in recent years to meet the increasing requirements of practical applications and to further extend the application areas.This paper reviews the various types of above-mentioned HTS filters as well as the developments of novel design methodologies.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42077244).
文摘Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Taking two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first surveyed.The results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively large.Subsequently,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity method.It is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero linearly.For this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance factor.The evaluation results obtained by this method match well with actual observations.In addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst pits.The potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth.
基金supported in part by the Key-Area Research and Development Program of Guangdong Province under Grant 2020B0101340002in part by the National Nature Science Foundation of China under Grants 61971415 and 61601456supported by the Youth Innovation Promotion Association of CAS under Grants Y2021004 and 2017009.
文摘Since the discovery of high temperature superconducting(HTS)materials in 1987,the performance of microwave filters such as insertion loss,selectivity,and out-band rejection has been significantly improved by utilizing HTS films.Nowadays,HTS filters have been widely used in wireless communications,space exploration,satellite communications,and several other fields.HTS filters with a special performance,such as wideband,dual-band or multiband,frequency tunable,and high power-handling capability have been designed and fabricated in recent years to meet the increasing requirements of practical applications and to further extend the application areas.This paper reviews the various types of above-mentioned HTS filters as well as the developments of novel design methodologies.
