Acoustic Field Numerical Analysis And Experimental Study Of Highway Tunnel

In recent years, with the highway construction process, there has been a lot ofhighway tunnels. Tunnels can greatly shorten the total length of the highway route andenhance road alignment, and improve safety and comfort of road driving experience.But simultaneously there are a series of environment drawbacks, such as the tunnelventilation black hole effect, dust, visibility, noise pollution, emergency rescue, etc. Theproblem of noise pollution is particularly serious. On the one hand, dirving in the tunnelhigh decibel noise environment, drivers and occupants will produce irritability, fear,which leads to inattention, seriously affect driving safety and comfort. On the otherhand, in case of emergency such as fire, explosion congestion, as the tunnel acousticenvironment is relatively poor, evacuation information is difficult to transfer to thetrapped, resulting in serious casualty and property damage. In this paper, theoreticalanalysis, field tests and numerical simulation methods are taken to study the highwaytunnel acoustic environment.The main contents of this paper as following:(1) Operating conditions of the existing highway tunnel and trend of developmenthave been introduced. The research status of acoustic environment of highway tunnelwas reviewed. Using basic acoustic classic theory, highway tunnel acousticenvironments were studied preliminary.(2) Based on the finite element method, numerical analyses were carried on toresearch the acoustic model characteristics and corresponding frequency. Longitudinaland lateral distribution of sound level was analyzed. The effects of sound absorptioncoefficient also were analyzed.(3) The attenuation time characteristics and distribution in tunnel are derived.(4) Design a set of real-time acoustic measurement for tunnel to carry out field test.The sound pressure level distribution, reverberation time, attenuation characteristicswere measured systematically. The results that measured in tunnle were compared withthe results of numerical analysis(5) Based on the results of (1),(2),(3),(4), using geometric reflection method toanalyze D/R and STI distribution of highway tunnel. The relation of D/R and STI wasfound and their spatial distribution characteristic was studied. To improve tunnel auditory environment, the scheme of tunnel cable broadcasting system are studied, thepublic broadcasting configuration were evaluated. The best scheme solution of publicbroadcasting is given.