Comparative Analysis of Various Kinds Concrete Creep Prediction Models

Author(s):  
Jun-Qing Lei ◽  
Hang Xu ◽  
Li-Qun Zou

The ratio of bridges to High-speed Railway line in China is very high. The influence of concrete creep to bridge structure is very high, so it is necessary to study creep of concrete in depth. In this thesis, experimental data of four important regions in China are collected, and the curves of concrete creep are analyzed. While, by comparing the domestic and foreign curves of Concrete Creep Prediction Models, the difference between them could be found. In addition, the theory of long-term deformation of concrete obtained by short-time experiment, which is proposed by Professor Bazant is used. According to experimental data, the creep curves are fittd by regression method. Finally, the comparison between common prediction models and Bazants’ theory is carried out, it can be found that the regression value is closed to the measured value.

Author(s):  
Gangqiang Yang ◽  
Yuxi Ma ◽  
Yongyu Xue ◽  
Xia Meng

Does the development of a high-speed railway (HSR) have a significant impact on the equalization of medical and health resources allocated among cities? Based on the panel data of 67 cities in China from 2007 to 2016, this paper investigates the direct and dynamic effects of HSR development on the equalization of medical and health services by using the difference-in-differences (DID) method. The empirical results show that an HSR connection significantly reduces the equalization level of medical and health services in cities and that the effect is larger for the period from the year of the connection to the second year. However, in the long term, HSR development improves the equalization level of medical and health services in cities. Heterogeneity tests show that the effect of the HSR connection shows an “N”-shaped trend under different city scales, the equalization level of medical resources in the largest cities benefit the most from HSR development, and the Eastern and Western regions of China are more sensitive to the HSR connection. While the allocation of medical resources is in the direction of equalization, the level of medical resources is significantly more equal with the HSR development in cities with stronger financial capacity and non-core cities. The analysis of other city characteristics provides policy recommendations for improving the public services delivery mode in China’s heterogeneous cities in terms of HSR development.


2014 ◽  
Vol 716-717 ◽  
pp. 342-346
Author(s):  
Xiao Jun Zhou ◽  
Bo Jiang ◽  
Yue Feng Zhou ◽  
Yu Yu

On the basis of different landform and multifarious topography in rugged mountainous area in southwest China, typical tunnel portals for single track tunnels in a new high speed railway line have been presented in the paper. The portal comprises headwall, shed tunnel, bridge abutment and its support. Portal with headwall is suitable for tunnel to resist front earth pressure on high and abrupt slope. Shed tunnel is placed in front of headwall so as to prevent rockfall; its outward part is built into a flared one. Meanwhile, the installation of bridge and its abutment are also included in the portal according to landform in the paper.


Author(s):  
Linggang Kong ◽  
Shuo Li ◽  
Xinlong Chen ◽  
Hongyan Qin

Vehicle on-board equipment is the most important train control equipment in high-speed railways. Due to the low efficiency and accuracy of manual detection, in this paper, we propose an intellectualized fault diagnosis method based on adaptive neuro-fuzzy inference system (ANFIS) network. Firstly, we collect the fault information sheets that are recorded by electrical personnel, using frequency weighting factor and principal component analysis (PCA) to realize the data extraction and dimension reduction; Then, in order to improve the fault diagnosis rate of the model, using genetic algorithm (GA) to optimize the parameters of the ANFIS network; Finally, using the fault data of a high-speed railway line in 2019 to test the model, the optimized ANFIS model can achieve 96% fault diagnosis rate for vehicle on-board equipments, which indicating the method is effective and accurate.


2017 ◽  
Vol 20 (3) ◽  
pp. 107
Author(s):  
V V Zagrebin

Предлагается модель анализа текущего состояния существующей инфраструктуры железнодорожной магистрали с целью последующего принятия организационно-технических решений на этапе инициации проекта высокоскоростной железнодорожной магистрали. Описываются возможные современные способы реализации высокоскоростного сообщения и их отличия в проектных и организационных решениях. Представлены основные элементы инфраструктуры железнодорожной магистрали, отдельно выделены факторы, влияющие на увеличение скорости движения. Представлена методика анализа, этапы и последовательность его проведения, принцип определения объектов анализа, возможные способы сбора данных по объектам анализа, перечень отраслевых геоинформационных и автоматизированных систем сбора и обработки оперативной информации по текущему состоянию инфраструктуры и эксплуатационной работе, методика обработки, обобщения, систематизации полученных данных для последующего анализа. Разработан общий алгоритм комплексного анализа технических и эксплуатационных параметров магистрали в виде последовательной блок-схемы. Данная модель актуальна при проведении анализа состояния инфраструктуры для всех существующих железнодорожных магистральных линий на территории России при выборе оптимальных и эффективных проектных решений совместно с экономическим обоснованием в процессе разработки комплексных мероприятий по внедрению высокоскоростного сообщения.


2013 ◽  
Vol 838-841 ◽  
pp. 1126-1129
Author(s):  
Zhao Lan Wei ◽  
Guo Jun Liu ◽  
Zu Yin Zou

Each related index was compared in three specifications, including Fundamental code for design on railway bridge and culvert, Code for rating existing railway bridges, and Code for design of high speed railway. The reasons of the difference existed in indexes was revealed, especially between high speed railway bridge and normal speed railway bridge.


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