| Urban road traffic noise pollution in China seriously affects the normal life of people around the roads.As a good porous sound-absorbing material,foamed concrete has good plasticity.Cost-effective noise reduction measures in the region.Therefore,this paper proposes a foamed concrete sound barrier(abbreviated as "FLC" sound barrier)on the basis of the existing research results of foamed concrete in the research group.Compared with traditional concrete sound barriers,FLC sound barriers have the advantages of good noise reduction performance,durability,economical and reasonable construction,and light construction,and have broad application prospects.In this paper,the mechanical and acoustic properties of FLC sound barriers are systematically studied from the three levels of material,unit plate,and sound barrier model by combining experimental analysis and numerical simulation.The research results can provide theories for its design and practical engineering application.in accordance with.The main research work and results of the article are as follows:1.Basic mechanical properties test of foamed concrete materials.Firstly,the basic material composition and dry density grade of this foamed concrete were identified as A09,and then the basic mechanical properties test of the material was carried out,including cube compressive strength test,split tensile strength test,axial compressive strength and elastic modulus The stress-strain constitutive relationship of foamed concrete is obtained by combining with the theoretical formula,which provides material parameters for subsequent model tests and numerical simulation studies.2.Experimental research on the bending resistance,impact resistance mechanical properties and sound absorption and acoustic performance of FLC sound barrier unit panels.The results show that the sound barrier unit board can withstand the ultimate load of 4.025 MPa and the impact energy of 100 J,the sound absorption and noise reduction coefficient is 0.71,and the weighted sound insulation is 46 d B,which meets the requirements of engineering use.3.Establish a 4m by 2m vertical FLC sound barrier test model in a semi-anechoic room to conduct noise reduction analysis experiments on the influence factors of sound barrier insertion loss.The results show that the lower the sound source is and the higher the sound barrier height is,the better the noise reduction effect of the FLC sound barrier is;for the sound barriers with different panel opening forms,rectangular openings,35% opening rate and 20 mm soundabsorbing hole depth are selected.The sound barrier panel can reduce the railway environmental noise as much as possible.4.Combined with ABAQUS and Virtual.lab software,a refined model of acoustic simulation of FLC sound barrier was established,and the simulation analysis of the insertion loss of the sound barrier was carried out,and the noise reduction mechanism of the insertion loss of the foamed concrete sound barrier was further revealed.The results show that the noise frequency response values of the noise barrier monitoring points below 400 Hz are all less than70 d B(A),which meets the requirements of the fourth category of urban road standards.On the near sound source side,the sound barrier insertion loss is 0;on the far sound source side,the sound barrier insertion loss is divided into three stages: interference,attenuation and stabilization.Compared with the single-sided sound barrier,the insertion loss of the doublesided sound barrier is significantly improved,up to 2 d B(A),and the increase is stable around2 d B(A)with the increase of the distance.The above research results can not only have a clear understanding of the insertion damage factors of the FLC sound barrier,but also play a role in promoting the refined development of the long-term noise reduction control of the FLC sound barrier,and provide a reliable design and construction basis for its engineering application. |
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