1 Project overview The“Beishan No.1”,the world’s first-ever hard rock Tunnel Boring Machine(TBM)tailored for high-gradient spiral tunnels,constitutes a pivotal element within the Beishan Underground Research Labora...1 Project overview The“Beishan No.1”,the world’s first-ever hard rock Tunnel Boring Machine(TBM)tailored for high-gradient spiral tunnels,constitutes a pivotal element within the Beishan Underground Research Laboratory(URL)initiative in China.Beishan URL,the first URL for geological disposal of high level radioactive waste(HLW)in China,is a national key construction project listed in the“13th Five-Year Plan”.In 2019,subsequent to receiving approval from the China Atomic Energy Authority,the Beijing Research Institute of Uranium Geology(BRIUG),serving as the project’s owner,initiated its construction.This underground facility,categorized as a“third generation”URL for HLW disposal,i.e.,area-specific URL,was located in Beishan,Jiuquan City,Gansu Province,China,following more than three decades of rigorous research on site selection.展开更多
This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge struct...This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge structure.The purpose of this paper is to provide robust support for enhancing the design quality of these bridges and ensuring their efficacy in real-world applications.展开更多
To improve the forming quality and forming limit of the numerical control （NC） bending of high-pressure titanium alloy tubes, in this study, using three-dimensional （3D） finite element method, deformation behavior...To improve the forming quality and forming limit of the numerical control （NC） bending of high-pressure titanium alloy tubes, in this study, using three-dimensional （3D） finite element method, deformation behavior of medium-strength TA 18 high-pressure tubes during NC bending with different bending radii is investigated. The results show that the cross-sectional deformation and the wall thickness variation during NC bending of TA18 tubes using a small bending radius （less than 2 times of tube outside diameter） are clearly different from that using a normal bending radius （between 2 and 4 times of tube outside diameter）. For bending with a normal bending radius, with or without a mandrel, the distribution of the flattening in the bending area resembles a platform and an asymmetric parabola, respectively. For bending with a small bending radius, with or without a mandrel, the flattening both distributes like a parabola, but the former has a stable peak which deflects toward the initial bending section, and the latter has a more pronounced peak with a bending angle and deflects slightly toward the bending section. The wall thickness variations with a normal bending radius, with and without a mandrel, both resemble a platform when the bending angle exceeds a certain angle. For the bending with a small radius, the distribution of the wall thickness variation without a mandrel follows an approximate parabola which increases in value as the bending angle increases. If a mandrel is used, the thickening ratio increases from the initial bending section to the bending section.展开更多
文摘1 Project overview The“Beishan No.1”,the world’s first-ever hard rock Tunnel Boring Machine(TBM)tailored for high-gradient spiral tunnels,constitutes a pivotal element within the Beishan Underground Research Laboratory(URL)initiative in China.Beishan URL,the first URL for geological disposal of high level radioactive waste(HLW)in China,is a national key construction project listed in the“13th Five-Year Plan”.In 2019,subsequent to receiving approval from the China Atomic Energy Authority,the Beijing Research Institute of Uranium Geology(BRIUG),serving as the project’s owner,initiated its construction.This underground facility,categorized as a“third generation”URL for HLW disposal,i.e.,area-specific URL,was located in Beishan,Jiuquan City,Gansu Province,China,following more than three decades of rigorous research on site selection.
文摘This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge structure.The purpose of this paper is to provide robust support for enhancing the design quality of these bridges and ensuring their efficacy in real-world applications.
基金National Natural Science Foundation of China(51175429)Program for New Century Excellent Talents in University(NCET-08-0462)+2 种基金Foundation of NWPU (JC201136)Fund of the State Key Laboratory of Solidification Processing in NWPU (KP200919)"111" Project (B08040)
文摘To improve the forming quality and forming limit of the numerical control （NC） bending of high-pressure titanium alloy tubes, in this study, using three-dimensional （3D） finite element method, deformation behavior of medium-strength TA 18 high-pressure tubes during NC bending with different bending radii is investigated. The results show that the cross-sectional deformation and the wall thickness variation during NC bending of TA18 tubes using a small bending radius （less than 2 times of tube outside diameter） are clearly different from that using a normal bending radius （between 2 and 4 times of tube outside diameter）. For bending with a normal bending radius, with or without a mandrel, the distribution of the flattening in the bending area resembles a platform and an asymmetric parabola, respectively. For bending with a small bending radius, with or without a mandrel, the flattening both distributes like a parabola, but the former has a stable peak which deflects toward the initial bending section, and the latter has a more pronounced peak with a bending angle and deflects slightly toward the bending section. The wall thickness variations with a normal bending radius, with and without a mandrel, both resemble a platform when the bending angle exceeds a certain angle. For the bending with a small radius, the distribution of the wall thickness variation without a mandrel follows an approximate parabola which increases in value as the bending angle increases. If a mandrel is used, the thickening ratio increases from the initial bending section to the bending section.
