Zeng Q.-Y.,China Railway Siyuan Survey and Design Institute Group Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010
On January 21 2006, the water and mud popped out from the 978 high-pressure and water-filled cavern at the exit to Maluqing tunnel. The water amount was instantaneously 300 thousand cubic meter per hour. For ensuring the safety of construction and traffic, a 4700 m-drainage tunnel was built to release the karst water in the Maluqing tunnel. To release the karst water includes the following 4 stages: water release by boring, water release by high place hole, water release by low place drainage tunnel, automatic release of water, mud and rock due to strong rainfall. The water release mechanism is summarized based on the measured data. To release water by boring can reduce the water pressure, but the water release ability is limited because of the boring blockage. To release water by the high place hole has certain effectiveness, but, if the high place hole encounteres the cavern, contineous construction will be difficult so as to have impact on the water release ability. As the drainage tunnel connects with the cavern, when the rainfall is strong, the water, mud and rock release from the drainage tunnel. So, the cavern is ceaselessly dredged, and the function of water release is satisfied. The maximum water release is corresponding to the rainfall.
Gong Y.-F.,China Railway Siyuan Survey and Design Institute Group Co. |
Zhang J.-R.,Southwest Jiaotong University |
Xu X.-D.,China Railway Siyuan Survey and Design Institute Group Co. |
Tang Z.,China Railway Siyuan Survey and Design Institute Group Co.
Journal of Railway Engineering Society | Year: 2015
Research purposes: In the dangerous difficult mountainous area, affected by the railway station setting and the contact line fork, there will be multi-line station tunnel and variable section tunnels, even form a super large section tunnel. When the shallow tunnel is located in stratum of completely weathered granite with abundant water, tunnel construction has the following security risks: the topographic and geological conditions are poor, developed groundwater, easy to collapse; Primary support force are large, deformation control is difficult, exit the risk of deformation intrude structure ambit, lose stability and collapse; Tunnel should be taken repeatedly excavation support, difficult force transfer, high security risk of support remove and replace. In view of the domestic and foreign less examples and research on super large cross section shallow tunnel in stratum of completely weathered granite with abundant water, there are less research on it. Based on the practical engineering, the problem is studied in this paper. Research conclusions: This paper summarizes the domestic and foreignnowadays construction technology of super large section tunnel, analyzes the mechanical behavior of tunnel constructive process, establishes measures of advanced support, support parameters of lining and constructive methods, the main conclusions are as follows: (1) The construction of super large section tunnel in stratum of completely weathered granite with abundant water is difficult, high security risk and high cost, should be combined with specific conditions of tunnel engineering to develop practical supporting measures and construction methods. (2) To control primary support deformation and primary supporting measures conversion of super large section tunnel in stratum of completely weathered granite with abundant water, large wall foundation and multiple supporting measures are necessary. (3)In order to control deformation of soft stratum with abundant water, deformation and collapse of super large cross section tunnel, should adopt strong advanced reinforcement and reinforcement measures of tunnel face. (4) The relevant research results can provide reference for the design and construction of the super large section tunnel in soft stratum. © 2015, Editorial Department of Journal of Railway Engineering Society. All right reserved.
Liu Q.-J.,China Railway Siyuan Survey and Design Institute Group Co Ltd
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2014
Taking Jijiang Yangtze river bridge in Chongqing as an example, the coupled vibration of wind, vehicle, and bridge of light rail-cum-road suspension bridges was studied. First of all, using the theory that the total potential energy of elastic system in dynamics is constant and the matrix "reserved seats" law, the dynamic equations of the suspension bridge and the vehicle-bridge coupling system were established respectively. Then, for the Jijiang Yangtze river bridge, the random wind field on the bridge site was simulated. Using the numerical wind tunnel technology, three component coefficients of train, girder and train-girder system model were calculated. On this basis, the coupled vibration of wind, vehicle, and bridge for the Jijiang Yangtze river bridge was carried out. The experimental results show that, when the wind speed is not more than 25 m/s, the designed bridge can meet the requirements of train safety and comfort, and the requirements satisfy the train operation control procedures standards made by China in case of high winds. It is shown that the influence of the bridge on the train operation under strong winds does not become a control factor for the whole railway line.
Zhu J.,China Railway Siyuan Survey and Design Institute Group Co.
Journal of Railway Engineering Society | Year: 2013
Research purposes: In recent years, people has begun to focus on the influence of lightning on the electrified railway. Especially the lighting activity in the heavy lightning areas brings the serious harm to the electrified railway in these areas. The lightning protection technology is an important for ensuring the reliability of the power supply system of the electrified railway. So the measures for the lightning protection must be strengthened and the lighting protection technology must be enhanced. Research conclusions: The three lines of defense should be built for the lighting protection for the substation to avoid the hit of the lighting strike to the substation devices, and the three level prevention should be built for avoiding the appearances of the failures of the low-voltage devices of the substation caused by the rising earth potential or the induced voltage and the induced current. Also the measures should be taken for the earthing system to make it in the good working state The lighting protection engineering for the substation should have the means mentioned above.
Luo S.,China Railway SiYuan Survey and Design Institute Group Co. |
Rao S.,China Railway SiYuan Survey and Design Institute Group Co.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2011
According to the mechanical characteristics of the curve cable-stayed bridge of four-track railway, the structure design and research on the cable, girder, bridge towers and foundation construction were launched by space bar finite element static analysis method in terms of the cable-stayed bridge architecture, the bridge stiffness, shrinkage and creep, and geometric nonlinearity etc. FEM analysis was used to study the stress distribution of the orthotropic steel box decks under the combined effect of the vertical and horizontal bending, shear lag and torsion warping. With FEM simulation, the local stress analysis and structure research were carried out on several aspects, such as the joint section of steel box girder and the prestressed concrete beam, the consolidation area between the main girder and the crossbeam of the bridge tower as well as the upper and lower steel anchor boxes for stay cable. Vehicle-bridge coupled time-varying analysis method was adopted to study the train running dynamic performance. Response spectrum method and seismic time history analysis method were used to study and analyze the seismic performance and seismic measures of the structure. Analyses show that about 3 m distance between the diaphragm and the web plates adopted for the steel box girder plays important role in improving the main beam structure in the curve cable-stayed bridge of four-track railway. Good train operation performance indicates that 1/900 deflection-span ratio adopted for the bridge to control the structural stiffness is more reasonable. E-type steel damping bearing has improved the seismic performance of the bridge.