In recent years, the use of terrestrial laser scanning （TLS） technique in engineering surveys is gaining an increasing interest due to the advantages of non-contact, rapidity, high accuracy, and large scale. Million...In recent years, the use of terrestrial laser scanning （TLS） technique in engineering surveys is gaining an increasing interest due to the advantages of non-contact, rapidity, high accuracy, and large scale. Millions of accurate 3D points （mm level accuracy） can be delivered by this technique with a high point density in a short time （up to 1 million points per second）, which makes it a poten- tial technique for large scale applications in engineering environments such as tunnels, bridges, and heritage buildings. Tunnels, in particular those with long lengths, create great challenges for surveyors to obtain the satisfactory scanned data. This paper presents a short history of TLS techniques used for tunnels. A general overview of TLS techniques is given, followed by a review of several applications of TLS for tunnels. These applications are classified as： detecting geological features of drilling tun- nels, monitoring the geometry of tunnels during excavation, making deformation measurements, and extracting features. The review emphasizes how TLS techniques can be used to measure various aspects of tunnels. It is clear that TLS techniques are not yet a common tool for tunnel investigations, but there is still a huge potential to excavate.展开更多
The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstruct...The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained.展开更多
基金financially supported by Special Fund for Basic Scientific Research of Central Colleges ( No. 2013G2241019 )Shaanxi Province Science & Technology Fund ( No . 2013KW03 )Xi'an City Science & Technology Fund ( No . CX1252 ( 8 ) )
文摘In recent years, the use of terrestrial laser scanning （TLS） technique in engineering surveys is gaining an increasing interest due to the advantages of non-contact, rapidity, high accuracy, and large scale. Millions of accurate 3D points （mm level accuracy） can be delivered by this technique with a high point density in a short time （up to 1 million points per second）, which makes it a poten- tial technique for large scale applications in engineering environments such as tunnels, bridges, and heritage buildings. Tunnels, in particular those with long lengths, create great challenges for surveyors to obtain the satisfactory scanned data. This paper presents a short history of TLS techniques used for tunnels. A general overview of TLS techniques is given, followed by a review of several applications of TLS for tunnels. These applications are classified as： detecting geological features of drilling tun- nels, monitoring the geometry of tunnels during excavation, making deformation measurements, and extracting features. The review emphasizes how TLS techniques can be used to measure various aspects of tunnels. It is clear that TLS techniques are not yet a common tool for tunnel investigations, but there is still a huge potential to excavate.
基金Project (2016YFB1200602-11) supported by National Key R&D Plan of China
文摘The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained.
