高速公路隧道内噪声声场分布特性

FEM-based study on distribution characteristics of noise field in highway tunnel

针对某高速公路隧道,把隧道壁及路面设置为全反射边界条件,以点声源作为基本噪声源建立了足尺有限元分析模型。利用LMS Virtual Lab软件对模型进行有限元分析,对隧道内声传播介质——空气进行声传播计算,研究了点声源条件下隧道内声场的分布特性及声源频率和位置对声场分布的影响。研究结果表明:公路隧道内噪声主要分为两大区域分布,贴近界面呈明显的规律性声压叠加与消减的声场紊乱区及远离界面的声场稳定区。声源频率从250Hz逐步增加到1 000Hz时,紊乱区的范围由距离隧道壁2.3m以内范围向0.7m以内递减;声源位置不同时,仅影响到声源附近5m范围内的声场,隧道内整体声场仍符合前述分布规律。参数分析表明隧道内噪声场主要分为平均声压级较高的紊乱区和较低的稳定区两大区域,声源频率会影响两区域分布范围,声源位置仅能影响声源附近小范围声场分布,对隧道整体声场影响不大。

In this paper, a full scaled model of a highway tunnel was established based on the Finite Ele- ment Method （FEM）. The tunnel wall and the pavement were set as total reflection boundary conditions and point acoutie source was used as the basic sound source. The model was analyzed based on FEM by using the software LMS Virtual Lab. And the sound propagation characteristic in air, which is the prop- agation medium in tunnel, was calculated. The sound pressure distribution of the tunnel and the influ- ence of sound source frequency and location on the sound pressure distribution were analyzed under the condition of point source. The research results show that the sound distribution is mainly divided into two large areas in the highway tunnels, the sound field disorder region which is close to the interface and presenting obvious regularity of sound pressure superposition and reduction, and the sound field stable region which is far away from the interface of sound field. When the frequency of the sound source increases from 250 Hz to 1 000 Hz, the range of the disordered region decreases from 2.3 m in the vicinity of the tunnel walls to 0.7 m. Changing of the sound source location can only affect the sound field within the range of 5 m away from the sound source, but the global sound field in-side the tunnel is essentially unchanged. The analysis of the parameters show that the sound field in the tunnel is mainly divided into two areas, the disorder area and the stable area. Sound source frequency can affect the distribution of the two areas. The sound source position can only influ- ence the range close to the sound source, but have slight influence on the sound field of the whole tunnel. 16 figs, 21 refs.