| 1. | Double track line
双线铁路 |
| 2. | Three dimensional stress analysis of double - tracks railway continuous rigid frame bridge with wide box girder
双线铁路连续刚构桥宽箱梁空间应力分析 |
| 3. | The analytic method and results in this paper has reference value to design and construction of box beams of double - track railways
本文所采用的分析方法和结论对于双线铁路箱梁的设计与施工有一定的借鉴意义。 |
| 4. | The upper level is for cars and has a width of 22 . 5 meters ; the lower level is railroad and has a width of 18 meter . the length of the bridge is 1670 meter ( 1 mile )
5米；下层为双线铁路，宽18米；全长1670米，正桥长156米，有两台8墩9米，每孔跨度128米。 |
| 5. | The upper level is for cars and has a width of 22 . 5 meters ; the lower level is railroad and has a width of 18 meter . the length of the bridge is 1670 meter 1 mile
长江大桥上层是公路，宽为22 . 5米下层为双线铁路，宽18米全长1670米，正桥长156米，有两台8墩9米，每孔跨度128米。 |
| 6. | Finally , based on the survey on the ventilation of double ( rack tunnels in operation representative parameters were selected and a series of computations were carried o ' ut to examine the train passing capacity of tunnels with different lengths and slopes
最后，根据对我国双线铁路隧道运营通风的调查分析，选择具有代表性的参数，利用数值计算程序，对不同长度和坡度的隧道在自然通风情况下列车的通过能力进行了模拟计算。 |
| 7. | By analyzing the relation between the train passing capacity and tunnel length as well as tunnel slopes the upper and lower limits for installing mechanical ventilation in railway double track tunnel have been determined , which provides science foundations for the formulation the ventilation design norm for railway double track tunnels in operation
通过对列车通过能力与隧道长度和坡度关系的进一步研究，得出了内燃牵引双线铁路隧道设置机械通风的上、下界限，为双线铁路隧道运营通风设计规范的制订提供了科学依据。 |
| 8. | Then a one - dimensional unsteady incompressible flow with moving pollutant source model was proposed . the continuity equation , momentum equation and convection - diffusion equation were discredited using finite volume scheme . thus a software for predicting the air velocity and pollutant in railway double track tunnels was developed
接着，根据双线铁路隧道运营通风的特点，建立了一维不可压缩非恒定流和流动污染源的物理模型以及山相应的连续性方程、动量方程和对流扩散方程构成的数学模型；在此基础上，利用数值计算方法，编制了一套双线铁路隧道运营通风的数值计算程序。 |
| 9. | A study on the limits for installing mechanical ventilation in railway double track tunnels in operation has been conducted . both numerical methods and field tests were used in the study . first , present situation of railway double track tunnels ; diesel locomotives with its pollutant emissions , and tunnel environmental hygienic standard ( tb1912 - 87 ) were reviewed
目前我国内燃牵引双线铁路隧道还没有设置机械通风的界限，针对这种情况，本文采用数值计算方法，结合现场试验，并根据tb1912 - 87的卫生标准，对设置机械通风的界限进行了深入的研究。 |
