scholarly journals Large-Scale Model Testing of High-Speed Railway Subgrade under Freeze-Thaw and Precipitation Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Shasha Zhang ◽  
Yantao Wang ◽  
Fei Xiao ◽  
Weizhi Chen
Keyword(s):  
Moisture Content ◽  
High Speed ◽  
Laboratory Tests ◽  
Large Scale ◽  
Saline Soil ◽  
Field Monitoring ◽  
Coarse Grained ◽  
Scale Model ◽  
High Speed Railway ◽  
Freeze Thaw

To determine whether coarse-grained saline soil meets the deformation requirements of the DY high-speed railway subgrade, a study was conducted by a combination of field-monitoring and laboratory tests. First, several temperature sensors were buried vertically in the ground of a typical section, and the temperature at different depths was monitored for nearly one year and analysed dynamically. It was determined that a depth of 4.8 m can be set as the constant-temperature layer. Then, based on the field-monitoring results, laboratory tests were carried out on a large-scale subgrade model under freeze-thaw and precipitation conditions. The change of temperature, moisture content, and soil deformation of the subgrade under long-term freeze-thaw and precipitation conditions were obtained. The results show that the temperature changes periodically with a V shape during the entire cycle. Twenty centimetres below the top surface is the sensitive depth of the sample, and salinity has little effect on temperature change. In the process of cycles, the average moisture content of soils with higher salinity is about 0.5% lower than that of soils with lower salinity. After nine freeze-thaw cycles, the sample finally shows dissolved settlement deformation. Precipitation mainly affects the deformation of the sample; however, the influence on salt-expansion and frost-heave deformation is less significant. Finally, by predicting the deformation of coarse saline soil, it is proven that the soil can meet the deformation requirements of high-speed railway foundations.

scholarly journals Monitoring and Modeling Railway Structures on High-Speed Lines with Asphalt Concrete Underlay: A Study on the Bretagne–Pays de la Loire Line

2020 ◽  
Vol 2674 (12) ◽  
pp. 600-607
Author(s):  
Diana Khairallah ◽  
Olivier Chupin ◽  
Juliette Blanc ◽  
Pierre Hornych ◽  
Jean-Michel Piau ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
High Speed ◽  
Large Scale ◽  
Strain Gages ◽  
Railway Transportation ◽  
Dynamic Stresses ◽  
High Speed Railway ◽  
High Frequencies ◽  
High Acceleration ◽  
High Speed Trains

The design and durability of high-speed railway lines is a major challenge in the field of railway transportation. In France, 40 years of feedback on the field behavior of ballasted tracks led to improvements in the design rules. However, the settlement and wear of ballast, caused by dynamic stresses at high frequencies, remains a major problem on high-speed tracks leading to high maintenance costs. Studies have shown that this settlement is linked to the high acceleration produced in the ballast layer by high-speed trains traveling on the track, disrupting the granular assembly. The “Bretagne–Pays de la Loire” high-speed line (BPL HSL), with its varied subgrade conditions, represents the first large-scale application of asphalt concrete (GB) as the ballast sublayer. This line includes 77 km of conventional track with a granular sublayer of unbound granular material (UGM) and 105 km of track with an asphalt concrete sublayer under the ballast. During construction, instruments such as accelerometers, anchored deflection sensors, and strain gages, among others, were installed on four sections of the track. This paper examines the instrumentation as well as the acquisition system installed on the track. The data processing is explained first, followed by a presentation of the ViscoRail software, developed for modeling railway tracks. The bituminous section’s behavior and response is modeled using a multilayer dynamic response model, implemented in the ViscoRail software. A good match between experimental and calculated results is highlighted.

Study on bearing structure and joint seismic resistance of large span non-landing arch on high-speed railway station

2019 ◽  
Author(s):  
Liu Chuanping ◽  
Tianluan Liu ◽  
Jian Jia
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Large Earthquake ◽  
Scale Model ◽  
Railway Station ◽  
High Speed Railway ◽  
Long Span ◽  
Weak Component ◽  
Double Beam ◽  
Cyclic Loading Tests

<p>The main entrance of Chongqing West Railway Station adopts the non-landing compound arch with a span of 108m. In this paper, the nonlinear finite element theory is applied to analyze the bearing capacity and seismic ductility of the compound arch joints. Low frequency cyclic loading tests are performed on the 1/5 scale model. Based on the calculation and test results, a double beam structure and a section of steel truss are placed in the arch joints to bear the force of the arch. Moreover, the buckling-restrained brace (BRB) is placed in the lower part of the arch that enables most force directly transmit to the foundation of the arch. Unlike BRB’s common use as an inter-column support, it now acts as a buckling constraint support in the large earthquake. For instance, it can be yielded before the frame column to improve earthquake resistance. The research results indicate that the compound arch joint structure successfully accomplishes the seismic design goals of strong joints with weak component. Moreover, the study provides the theoretical basis and design reference for the application of BRB and long-span arch structures in high-speed railway station.</p>

New insights into the frost heave behavior of coarse grained soils for high-speed railway roadbed: Clustering effect of fines

2019 ◽  
Vol 167 ◽  
pp. 102863 ◽  
Author(s):  
Wei She ◽  
Luansu Wei ◽  
Guotang Zhao ◽  
Guotao Yang ◽  
Jinyang Jiang ◽  
...  
Keyword(s):  
High Speed ◽  
Coarse Grained ◽  
Frost Heave ◽  
High Speed Railway ◽  
Clustering Effect

scholarly journals Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ding Youliang ◽  
Wang Gaoxin
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
High Speed ◽  
Field Monitoring ◽  
Generalized Extreme Value Distribution ◽  
Monitoring Data ◽  
Load Factor ◽  
High Speed Railway ◽  
Arch Bridge ◽  
The Impact

Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF) to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

Dynamic Scheduling Model and Algorithm for Dispatching Trains in High-Speed Railway Passenger Station

2010 ◽  
Author(s):  
Yixiang Yue ◽  
Leishan Zhou
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Job Shop ◽  
Dynamic Scheduling ◽  
Time Window ◽  
Real Life ◽  
Greedy Heuristic ◽  
Railway Station ◽  
High Speed Railway ◽  
Railway Passenger

Regarding the railway station tracks and train running routes as machines, all trains in this railway station as jobs, dispatching trains in high-speed railway passenger stations can be considered as a special type of Job-Shop Problem (JSP). In this paper, we proposed a multi-machines, multi-jobs JSP model with special constraints for Operation Plan Scheduling Problem (OPSP) in high-speed railway passenger stations, and presented a fast heuristic algorithm based on greedy heuristic. This algorithm first divided all operations into several layers according to the yards attributes and the operation’s urgency level. Then every operation was allotted a feasible time window, each operation was assigned to a specified “machine” sequenced or backward sequenced within the time slot, layer by layer according to its priority. As we recorded and modified the time slots dynamically, the searching space was decreased dramatically. And we take the South Beijing High-speed Railway Station as example and give extensive numerical experiment. Computational results based on real-life instance show that the algorithm has significant merits for large scale problems; can both reduce tardiness and shorten cycle times. The empirical evidence also proved that this algorithm is industrial practicable.

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