Wu S.-F.,Design and Research Institute Co.
Bridge Construction | Year: 2014
The Gusaoshu Road Overpass Spanning Railways is a prestressed concrete continuous box girder bridge of variable section with span arrangement (70+116+70) m and deck width 32 m. Considering that the overpass is required to span 11 railway lines and to ensure the safe operation of the railways during the construction and minimize the interference of the construction to the railways, it is determined in the design that the overpass should be constructed by the rotation erection method (with the rotating weight being 17 300 t and the maximum rotating angle being 106°) and the closure segment of the central span should be shifted 9.25 m from the right center of the central span towards the direction of the main mileage. The main girder of the overpass is of the cross section of five cells and single box. The main piers are the m-shape piers to be supported on the bored pile foundations. The rotation system is mainly comprised of the bearing system, pushing and hauling system and the balancing system. The dimensions of the spherical hinges are respectively 4 m for the Pier Z63 and 3.9 m for the Pier Z64. The software MIDAS Civil 2011 and MIDAS FEA are used to calculate the static forces of the main girder, m-shape main piers, rotation system, cross beams and deck slabs. The results of the calculation show that the various indices of the overpass can satisfy the relevant requirements in the codes. Source
Jin G.-D.,Design and Research Institute Co.
Journal of Railway Engineering Society | Year: 2013
Research purposes: In urban area, the design of tunnel usually needs to consider certain interchange relations with other tunnels (or other structures), such as overpass, underpass, etc. These adjacent and interchange relations are the difficult and important points for designing tunnel, so they become the control factors for tunnel design and construction. New Zhongliangshan Tunnel of Chengdu-Chongqing Passenger Line has different interchange relations with existing tunnels and it is highly influenced by the existing tunnels and interchange relations. Different adjacent tunnel design requires quite different construction method, which means how to guarantee the construction safety and operation security of the existing tunnels are the research focuses in this paper. Research conclusions: According to the research, it can be drawn: (1) When the new tunnel under wear both tunnel, can through the adoption of forepole controlled blasting and ensure the safety of the tunnel construction safety and existing lines. (2) New super small clear distance tunnel across both the tunnel, in the case of clearance limit llowed, can through the tunnel reinforcement and grouting behind the lining, by improving the existing tunnel structure to ensure the safety of the existing tunnel. (3) For the proposed subway down through the tunnel under construction, the proposed subway can be applied through the tunnel under construction for auxiliary measures can be applied in advance for interchange effect, reduce the influence of the planned tunnel on existing tunnel, ensure safety. (4) For two proposed tunnel, when the first a lower tunnel construction, should be considered in the late on across the tunnel construction load and operating load, the influence of the primary support and secondary lining consider appropriate to strengthen. (5) When across the tunnel on the early construction, priority and tunnel construction during this period, reduce the wear on the tunnel construction on across the influence of the tunnel. (6) This research result can be applied in tunnel near the design of the tunnel section. Source
Jiang D.-Y.,Dalian Maritime University |
Feng Z.-Q.,Dalian Maritime University |
Zhang J.-D.,Dalian Maritime University |
Wu P.-L.,Design and Research Institute Co.
Dalian Haishi Daxue Xuebao/Journal of Dalian Maritime University | Year: 2014
With the fuel common rail system of RT-flex diesel engine as the simulation object, the working principle and structural features were studied. The mathematical models of high pressure fuel oil pump, intermediate fuel accumulator, fuel rail ICU piston as well as injector were established. Simulink results show that the mathematical models are proper. The visual simulation system of the common fuel rail system in RT-flex diesel was developed by VS2012. The visual simulation system can display the working principle and running of the common fuel rail system, which is useful in developing marine engine simulator and training candidates. Source
Ying H.,Zhejiang University |
Nie W.,Design and Research Institute Co. |
Huang D.,Third railway survey and design institute group corporation
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014
Groundwater level in coastal region fluctuates periodically due to wave or tides. The response of the pore pressures of the ground near the retaining wall is vital for pit excavation. In this study, a single layer ground with finite thickness around the pit to be excavated was considered to be isotropic and homogeneous. The fluctuating water level at the boundary was assumed to be a sinusoidal function. The seepage area around the pit was divided into three zones. Assuming the total stresses of soil keeping constant, the two-dimensional consolidation equations were decoupled. A semi-analytical solution of pore pressure of the ground around the pit with gravity retaining wall in response to the groundwater level fluctuation was derived with Laplace and Fourier transforms. The comparisons with the results from finite element software PLAXIS verified the proposed method. An example was presented to investigate the pore pressure response around the pit and its influence on the stability of the retaining wall via the above semi-analytical solution. The results show that the amplitude of pore pressure attenuated along the seepage path from the back to the front of the retaining wall, while the phase lag increased. The stability of the retaining wall fluctuates and has phase lags too as the groundwater level fluctuating. Source
Li X.-G.,Beijing Jiaotong University |
Sun H.-C.,China Railway Electrification Bureau Group Co. |
Zhang J.-Q.,Design and Research Institute Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011
The PLC hydraulic synchronization control system is used to control the deformation of the existing metro structure during the construction of Dongzhimen Station of Airport Line under the reentry line of Dongzhimen Station of Line 13 of Beijing Metro. Combined with the construction sequences of the drift and pile method, the idea of zoning, phasing, grouping, and staging is adopted to design the overall jacking scheme. The zoning idea refers to the respective calculation of the jacking force according to different structure types of the existing line; the phasing idea means that three phases are divided based on typical construction cases and the control scheme at each phase is respectively made; the grouping idea refers to driving the jacks into different groups and grouping control; the staging idea means the implementation of staged control of the jack force of each group and slow increase of the jacking force to reach the design values. Based on the measured deformations of the existing line, the 3rd phase jacking scheme is executed six times. Practice shows that the PLC hydraulic synchronization control jacking technology may slow the settlement speed and reduce the settlement amount of the existing structures to ensure the safe operation of the existing line, which is an active defense method. Source