为比较不同轨下基础噪声水平,通过ABAQUS建立声-固耦合模型,模拟结构振动产生的声场中的噪声变化.选取声场中的声压值转化得到的声压级值作为定量评价两种沥青混凝土轨下基础（ACRS-1型、ACRS-2型）和普通板式（Slab Track）结构产生的噪声水平.结果表明,选用的声-固耦合模型可以较好地评估不同轨下基础下噪声.比较3种轨下基础结构可以发现,总体上,ACRS-1型和ACRS-2型结构要比普通板式结构的噪声要低,特别是ACRS-2型结构,比其他两种结构的噪声均要低.噪声降低的幅值出现在0.01、0.02、0.03 s附近,尤其在0.02 s附近,ACRS-2型结构低于普通板式结构的噪声幅值10~20 d B,ACRS-1型结构低于普通板式结构的噪声幅值5 d B左右.
A numerical analysis using a finite element program was performed on three structures:hot mix asphalt(HMA) reinforced trackbed(RACS-1),HMA directly supported trackbed(RACS-2),and traditional Portland Cement Concrete(PCC) slab track(SlabTrack).Although the comprehensive dynamic responses of RACS-1 were similar with SlabTrack,HMA layer can positively affect the stress distributions.In particular,the horizontal stresses indicate that the resilience of RACS-1 was improved relative to SlabTrack.In addition,HMA reinforced substructure has the capacity to recover the residual vertical deformation.The effective depth for weakening dynamic loadings is mainly from 0 to 2 m,this being especially true at 0.5 m.The results from the analysis show that HMA is a suitable material for the railway substructure to enhance resilient performance,improve the stress distribution,weaken dynamic loading,and lower the vibration,especially at the effective depth of 2 m.The HMA constructed at the top of the stone subbase layer allows the vertical modulus a smooth transition.In terms of the comprehensive dynamic behaviors,RACS-1 is better than SlabTrack,while the results for RACS-2 are inconclusive and require further research.
Mingjing FANGYanjun QIUJerry G. ROSERandy C. WESTChangfa AI
