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Fei G.-H.,Central South University | Fei G.-H.,Key Laboratory of Engineering Structure of Heavy Railway | Wu X.-P.,Central South University | Wu X.-P.,Key Laboratory of Engineering Structure of Heavy Railway | And 2 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2015

To study the influence of sound barriers with different heights on the noise reduction effect, a noise reduction model of sound barrier for high-speed railway was established. Based on a certain section of Wuhan-Guangzhou high-speed railway, the noise reduction effects of the vertical noise barriers with different heights and conditions were simulated and analysed by the software ANSYS and SYSNOISE. Results showed that, the working efficiency of the sound barrier decreased with the increase of the train speed. And under the same speed, the noise reduction effect of the ground noise barrier is more satisfactory than the bridge barrier. Data according to MATLAB numerical calculation showed that the insertion loss of each observation point is a logarithmic formula of the height. The relationship between noise attenuation and the height of barrier was not a linear one, the growth rate of the insertion loss was smaller as the height increased on the same scale. According to the need of noise reduction and the economics, the suitable height of the subgrade sound barrier is 3.45~3.95 m. And when the train runs at a high speed above 350 km/h, the suitable height of the bridge sound barrier should be more than 3.15 m. ©, 2015, Chinese Society for Environmental Sciences. All right reserved. Source

Ma K.L.,Central South University | Ma K.L.,HIGH-TECH | Ma K.L.,Key Laboratory of Engineering Structure of Heavy Railway | Xie Y.J.,Central South University | And 8 more authors.
Science China Technological Sciences | Year: 2014

The dynamic mechanical property of concrete is one of the key parameters, which greatly influences durability of infrastructures subjected to continuous heavy loading, such as girder and track slab of high-speed railway foundation structure. This paper reports serials of experiments designed to investigate the deterioration of dynamic mechanical properties of different concretes under fatigue loading condition. Four parameters including relative dynamic elastic modulus (RDEM), relative dynamic shear modulus (RDSM), relative compressive strength (RCS) and water absorption (WA) of concrete were evaluated to assess the dynamic properties and microstructures of concretes. Results show that the fatigue stress levels and fatigue cycle durations significantly influence the dynamic mechanical properties of concrete including dynamic elastic modulus and dynamic shear modulus. Addition of proper mineral admixture can improve the dynamic mechanical characteristics of concrete and increase its resistance against the fatigue loading effect. Keeping the amount of mineral admixture in concrete constant, its dynamic mechanical property with fly ash is lower than that with fly ash and silica fume. The water absorption in concrete, which is an indirect parameter reflecting capillary porosity, increases evidently after bearing fatigue-loading. There is a close correlation between the deterioration of dynamic mechanical property and the increasing of water absorption of concrete. This indicates that the damage of microstructure of concrete subjected to fatigue loading is the indispensable reason for the decay of its dynamic mechanical performance. © 2014, Science China Press and Springer-Verlag Berlin Heidelberg. Source

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