Nanjing, China
Nanjing, China

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Niu Z.L.,Xi'an University of Technology | Niu Z.L.,China Railway 13th Bureau Group Co. | Qi Y.B.,China Railway 13th Bureau Group Co. | Huang J.S.,The 2nd Engineering Co. | And 2 more authors.
Applied Mechanics and Materials | Year: 2014

The article proposed the reliability calculation method for tunnel lining design combining Rock-Mechanics model and Monte Carlo finite element method. The reliability calculation model of tunnel lining structure design was established considering tunnel character. The types of the statistical characteristics and distribution of axial force for the big cross section of the loess tunnel structure had been summarized. The study result stated that the method is feasible. It has important theoretical guiding significance to the practice structure reliability design of tunnel and underground engineering. © (2014) Trans Tech Publications, Switzerland.

Sun M.,The 2nd Engineering Co..
Modern Tunnelling Technology | Year: 2014

The exit section (510 m) of the Xiuning tunnel on the rebuilt Chengdu-Kunming railway, passing under the Longtan reservoir, is located in the Luoci-Yimen fault zone. The stratum is composed of rare water-rich mylonite with a classification of grade VI. After excavation, mylonite in the form of plastic flow can easily cause mud gushing and collapse, resulting in large deformation of the primary lining. To pass through this stratum safely and quickly, the deformation of the surrounding rock has to be controlled. Based on a water stability test of mylonite shear strength, this paper presents a support method for this section, namely, full-face pre-grouting with pipe-roof support. Using numerical simulation and deformation monitoring of the surrounding rock and lining structure, it was proven that full-face pre-grouting can effectively achieve water blocking, water squeezing, drainage consolidation and rock strength improvement; pipe-roof pre-support and three-bench seven-step excavation can effectively control rock deformation, ensuring construction safety.

Tong L.-H.,China Railway Major Bridge Engineering Group Co. | Xiao J.-W.,The 2nd Engineering Co. | Wang L.,The 2nd Engineering Co.
Bridge Construction | Year: 2013

The main bridge of Anqing Changjiang River Railway Bridge is a steel truss girder cable-stayed bridge with double pylons, triple cable planes and with span arrangement(101.5+188.5+580+217.5+159.5+116) m. The stay cables of the bridge are the ones formed by the φ7 mm hot galvanized steel wires with hot extruded polyethylene sheaths, of which the longest cable is 301.750 m and the heaviest single cable is 37.3 t. Since the pylon and main girder at Pier No.4 of the bridge was to be partially constructed concurrently and to achieve the rapid and safe installation of the cables at the pier, the reeled cables were lifted onto the bridge by the tower crane and deck crane. The stay cable unreeling way was arranged at the truss top of the main and side spans and the installation of the cables on the pylon was completed by two ways of lifting by the tower crane and pylon top lifting frame. After the reeled cables were lifted in place, the cables were unreeled on the truss top. The short and medium cables at the main girder were installed by the guiding system and winch and the long cables there were installed by the guiding system, winch hauling system and the soft hauling system. A group (6 nos.) of the cables on the pylon was tensioned concurrently, symmetrically and in stages. Presently, the installation and initial tensioning of the cables at pier No.4 have been all completed.

Tong L.-H.,China Railway Major Bridge Engineering Group Co. | Wang L.,The 2nd Engineering Co.
Bridge Construction | Year: 2013

The main bridge of Anqing Changjiang River Railway Bridge is a steel truss girder cable-stayed bridge with double pylons and triple cable planes. The steel truss girder of the bridge is designed as the parallel truss type of N-shape and is composed of three main trusses. The girder of the main bridge in the areas without stay cables has 12 panels, totally weighing 6 041.5 t. The panels of the girder were installed by the piece-by-piece assembling method, of which the 8 panels between the Pier No.6 and Pier No.7 were installed on staging and the 4 panels between the Pier No.6 and Pier No.5 were installed by the cantilever method. The piers of the staging were arranged at the locations corresponding to each panel point of the girder and totally 7 arrays of the temporary piers were arranged. In each array of the piers, there were 6 steel pipe piles and the piles were driven in and extended by the vibrating hammer. The panels of the girder were lifted and installed and the erection of the girder was completed by the repeated utilization of the 200 t capacity floating crane alternatively placed at the downstream and upstream sides. The erection of the steel truss girder of the bridge was completed on October 15, 2011 and the inspection of the erection proved that the geometric shapes and stress of the girder in the areas without stay cables could accord with the design requirements.

Li Z.,Beijing Jiaotong University | Bai M.,Beijing Jiaotong University | Xu Z.,Beijing Jiaotong University | Zhao X.,The 2nd Engineering Ltd Company | And 2 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2011

Qiyueshan tunnel engineering of Yichang-Wanzhou Railway was taken as the research background. Based on the karst geological conditions in hazardous section, 3D finite element analysis method was applied to simulate and analyze the deformation and damage law of the tunnel face with different rock mass thickness and different karst water pressure under three conditions, namely, the scale of the karst cave in front of the tunnel face is greater than, equal to and less than the scale of the tunnel face. The results indicate that when the diameter of the karst cave is greater than or equal to the tunnel diameter, the deformation values of the tunnel face are similar under the action of the same karst water pressure. When the diameter of the karst cave is less than the tunnel diameter, the deformation of the tunnel face is small. The maximum deformation of the tunnel face appears in the center position of the tunnel face. When the distance between the tunnel face and the wall of the karst cave is greater than 2.0 m, the increase in the deformation of the tunnel face is not obvious. Under the condition that there is no water pressure in the karst cave, the plastic area of the tunnel face rock mass is very small. However, the plastic area will gradually increase along with the increase of water pressure.

Li K.,The 2nd Engineering Co.
Advances in Energy, Environment and Materials Science - Proceedings of the International Conference on Energy, Environment and Materials Science, EEMS 2015 | Year: 2016

This article establishes a nonlinear finite element model based on the general finite element method, and simulates the stress of the reinforced rust caused by the reinforced concrete in the arch foot of the Xixihe bridge. Based on the finite element numerical analysis, the calculation method of the corrosion rate of reinforced concrete corroded reinforcement is presented. Numerical calculation and analysis, including the concrete component angle of reinforcement corrosion and central reinforcement corrosion of uniform corrosion expansion force of concrete member, based on previous reinforcement corrosion distribution theory analysis results, combines with the results of the numerical analysis of the corrosion expansion force, to calculate the arch foot concrete cover cracking moment of steel corrosion rate, predict the Xixihe bridge arch foot concrete protective layer cracking time, and provide the reference for the design. © 2016 Taylor & Francis Group, London.

Yang X.-J.,Tongji University | Hu Z.-D.,Tongji University | Liang J.,Marine Design and Research Institute of China | Jia H.-R.,The 2nd Engineering Co.
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2014

Based on the scattering theory of elastic waves, the scattering of SH wave and the dynamic stress concentration around circular tunnel with lining were investigated by employing the wave function expansion and mirror methods. The analytical solution of the problem, which was taken as a group of unlimited algebraic equations, was derived, and the numerical solution of the dynamic stress concentration factor around the lining was given. The effects of the shear elasticity of the surrounding rock and the lining, together with the wave number on the dynamic stress concentration factors were analyzed. It is shown that the shear elasticity of the surrounding rock and the wave number are factors that influence dynamic stress concentration, which may provide important theoretical basis for the earthquake evaluation of lining.

The usage amount of concrete for the in-water pier works of the Hutong Changjiang River Bridge is 1325000 m3. To determine the supply systems of such a huge amount of the concrete for construction of the pier works, the general plans of the concrete mixing plants were made in the light of the riverbed elevation, the specific required amount of the concrete and also in consideration of the shallow and deep water areas. Through comparison of the supply capacity, construction difficulties, construction periods and construction cost of the two schemes of the steel platform mixing plant and hydraulic reclamation island mixing plant, it was finally determined that in the shallow water area, a reclamation island mixing plant should be applied. The height of the island would be about 6.1 m and at the outside of the surrounding dyke, a ring of the 1 m high and 0.3 m thick cast-in-situ concrete retaining wall would be arranged. In the deep water area, the steel platform mixing plants (made up of the steel pipe piles+pile top distribution beams+Bailey truss beams+steel floor systems) should be applied. For the reclamation island mixing plant in the shallow water, the surrounding dyke would be constructed first, the reclamation sand inside the cofferdam and the side slope protection outside the cofferdam would be then constructed. The rubble stone base would be laid and the concrete would be finally cast to form a platform. For the steel platform mixing plants, the steel pipe piles would be set and driven first and the bracing systems connecting the piles, the pile top distribution beams, platform main beams and the floor systems would be then successively constructed. © 2015, Journal Press, China Railway Bridge Science. All right reserved.

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