A case of Qinghuayuan tunnel excavation below the existing Beijing Subway Line 10 is presented.The new Qinghuayuan tunnel,part of the Beijing-Zhangjiakou High-speed Railway,was excavated by a shield machine with an ou...A case of Qinghuayuan tunnel excavation below the existing Beijing Subway Line 10 is presented.The new Qinghuayuan tunnel,part of the Beijing-Zhangjiakou High-speed Railway,was excavated by a shield machine with an outer diameter of 12.2 m.The existing subway was excavated by shallow tunnelling method.The project layout,geological conditions,reinforcement measures,operational parameters of shield machine and monitoring results of the project are introduced.During the Qinghuayuan tunnel excavation below the existing subway,total thrust,shield driving speed,cutterhead rotation speed and torque were manually controlled below the average values obtained from the previous monitoring of this project,which could effectively reduce the disturbance of the surrounding soil induced by shield excavation.The Gaussian fitting function can appropriately fit both the ground and the existing subway settlements.The trough width is influenced not only by the excavation overburden depth,but also by the forepoling reinforcement and tail void grouting measures.展开更多
An optical transceiver with a novel optical subassembly structure is proposed in this paper, which achieves high coupling efficiency and low assembly difficulty. The proposed optical transceiver consumes 0.9 W power a...An optical transceiver with a novel optical subassembly structure is proposed in this paper, which achieves high coupling efficiency and low assembly difficulty. The proposed optical transceiver consumes 0.9 W power and retains a small size of 28 mmx16 mmx3 mm. The fabrication process of the silicon substrate and the assembly process of the optical transceiver are demonstrated in details. Moreover, the optical transceiver is measured in order to verify its transmission performance. The clear eye diagrams and the low bit error rate （BER） less than 1013 at 10 Gbit/s per channel show good transmission characteristics of the designed optical transceiver.展开更多
基金Project(U1934210)supported by the Key Project of High-speed Rail Joint Fund of National Natural Science Foundation of ChinaProject(8202037)supported by the Natural Science Foundation of Beijing,China。
文摘A case of Qinghuayuan tunnel excavation below the existing Beijing Subway Line 10 is presented.The new Qinghuayuan tunnel,part of the Beijing-Zhangjiakou High-speed Railway,was excavated by a shield machine with an outer diameter of 12.2 m.The existing subway was excavated by shallow tunnelling method.The project layout,geological conditions,reinforcement measures,operational parameters of shield machine and monitoring results of the project are introduced.During the Qinghuayuan tunnel excavation below the existing subway,total thrust,shield driving speed,cutterhead rotation speed and torque were manually controlled below the average values obtained from the previous monitoring of this project,which could effectively reduce the disturbance of the surrounding soil induced by shield excavation.The Gaussian fitting function can appropriately fit both the ground and the existing subway settlements.The trough width is influenced not only by the excavation overburden depth,but also by the forepoling reinforcement and tail void grouting measures.
基金supported by the National High Technology Research and Development Program of China(No.2015AA016904)
文摘An optical transceiver with a novel optical subassembly structure is proposed in this paper, which achieves high coupling efficiency and low assembly difficulty. The proposed optical transceiver consumes 0.9 W power and retains a small size of 28 mmx16 mmx3 mm. The fabrication process of the silicon substrate and the assembly process of the optical transceiver are demonstrated in details. Moreover, the optical transceiver is measured in order to verify its transmission performance. The clear eye diagrams and the low bit error rate （BER） less than 1013 at 10 Gbit/s per channel show good transmission characteristics of the designed optical transceiver.
