Time filter

Source Type

Liu X.,Jinan Rail Transit Group Co. | Xiang Z.,Tongji University | Niu J.,Tongji University | Xia K.,Tongji University | And 3 more authors.
International Journal of Electrochemical Science | Year: 2015

The corrosion behaviors of amorphous, nanocrystalline and crystalline Ni-W alloys coating were systematically investigated by ultrasonic-assisted direct current electrodeposition. Through potentiodynamic polarization test and electrochemical impedance spectroscopy analysis, it was found the self-corrosion trend of nanocrystalline coating < crystalline coating < amorphous coating, whereas the anti-corrosion property trend of nanocrystalline coating > crystalline coating > amorphous coating in alkaline solution contrary to that in acid solution. The mechanism of corrosion resistance is amorphous homogenous structure and WO3 films in acid solution and coating high electrical resistance in alkaline solution corresponding to different structure, respectively.

Liu Y.-J.,Shanghai JiaoTong University | Liu Y.-J.,Ecole Centrale Nantes | Liu Y.-J.,Shanghai Tunnel Engineering & Rail Transit Design and Research Institute | Wang J.-H.,Shanghai JiaoTong University | And 5 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015

The granular materials are widely used in geotechnical engineering, whose grading changing feature will affect their mechanical behavior obviously, especially the bearing capacity. In order to well describe the influence of grain-size distribution on the mechanical behavior of granular materials, a simple constitutive model taking into account the grading-dependent critical state line is developed within the framework of elasto-plasticity and the critical state theory. The model is used to simulate the drained and undrained triaxial compression tests on different types of granular materials (DEM ideal sphere, artificial material glass ball and natural material Hostun sand). It is found that only one group of grading-dependent critical state parameters is needed for describing the mechanical response of granular materials with different gradings. ©, 2015, Chinese Society of Civil Engineering. All right reserved.

Wang W.,Shandong University of Science and Technology | Sun J.,Shandong University of Science and Technology | Sun J.,Jinan Rail Transit Group Co. | Lu L.,Shandong University of Science and Technology | Lu L.,BGI Engineering Consultants LTD.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2016

For overcoming the difficulty of in-situ stress testing caused by borehole collapse, softening and disintegration under water in weakly consolidated soft rock, an inversion analysis method of initial in-situ stress was proposed. On the basis of damped least square method, the improved displacement solutions of roof, floor and wall of straight wall-semicircle arch roadway were respectively established by introducing the geometric modified coefficients to revise the theoretical displacement solutions of circular roadway. The distribution of in-situ stress was determined according to the field displacement test data of roadway in Yili No.4, and forward verification for in-situ stress was carried out by numerical analysis. The results show that the improved displacement solution of roadway is highly fitted with the numerical simulation and field test data. The gravity stress is the dominant geostress in the testing mining area, and the maximum horizontal principal stress is 0.7~0.8 times the vertical stress. The direction of maximum horizontal stress dimension is N10°E~N20°E, which is important directional influence on drivage and arrangement of roadway. © 2016, China University of Mining and Technology. All right reserved.

Wang G.,Shandong University of Science and Technology | Wang G.,Jinan Rail Transit Group Co. | Lu L.,Jinan Rail Transit Group Co. | Sun J.,Shandong University of Science and Technology
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2015

In the tunneling of the Jinan rail transit line R1 passing under Lashan River, the stability of surrounding rock, the effect of shield thrust and the sensitivity of interface parameters were analyzed employing both the theoretical calculation and numerical method. The study showed that, as the shield passed through the medium interface, the settlement of surrounding rock at arch crown increased firstly and then decreased, while the principal stress in the lining segment increased firstly, then declined and rebounded. The interface effect reached 4 meters to the front and 10 meters in behind. If the safety factor was 2, the support stress ratios maintaining the stability of rock medium, soil medium and excavation face of watercourse were 0.24-2.80, 0.34-1.65, 0.54-1.40, respectively. The rock-soil interfacial effect was found to increase with the increase of stiffness ratio of medium and interface dipping angle. Especially in the situation of k≥4 and θ≥20°, the disturbance sensitivity of interface surrounding rock thrust became more significant. © 2015, Science Press. All right reserved.

Wang G.-F.,Jinan Rail Transit Group Co. | Yang P.-S.,Jinan Rail Transit Group Co. | Liu H.-D.,Jinan Rail Transit Group Co.
Journal of Railway Engineering Society | Year: 2016

Research purposes: Train is the direct carrier of passangers in urban rail transit, and train marshalling form involves the urban planning, passenger flow, train operation, line network resource sharing, and so on. From the perspectives of urban rail transit line characteristics, traffic volume forecasting, vehicle capacity, transport capacity matching, line network resource sharing, dynamic ratio of motor cars and trailers and economy, the optimal Jinan rail R1 line train marshalling was determined through the break-even analysis. Research conclusions: (1) Considering various factors, 4-4-6 marshalling is recommended for Jinan rail transit R1 in the early, the near future and the far future stages. The ratio of motor cars and trailers is 3:1 in the early and the near future, 4:2 in the far future. (2) Passenger flow prediction is the main factor affecting vehicle type and train marshalling selection, depending on urban planning and development. (3) According to the breakeven analysis, train expansion after 10 years of operation is a more economical solution. (4) The results have been applied on the design of Jinan rail transit R1, and can provide a reference for the similar projects. © 2016, Editorial Department of Journal of Railway Engineering Society. All right reserved.

Discover hidden collaborations