对无砟轨道吸声板降噪措施效果的评价与分析

对框架型和双块式无砟轨道结构铺设吸声板前后进行了列车辐射噪声测试，结果表明：在距线路中心线3．75m、于轨面1．5m处，框架型板式无砟轨道结构噪声降低约2dB（A），双块式无砟轨道结构降低约1dB（A），该吸声板的吸声系数在315～3150Hz的中高频段有较好的吸声效果，能够有效吸收列车通过时主要分布在500～4000Hz中高频段的辐射噪声能量，具有一定的吸声效果。并对产生不同吸声效果的原因进行了分析。该测试结果可供铁路建设项目环境影响评价参考和借鉴。

Evaluation and Analysis on the Effect of Noise Mitigation Measures for Railway with Ballastless Track

Railway noise was measured on frame-structured ballastless track and double-block ballastless track before and after sound absorption board was laid. Result showed that Railway noise on frame-structured ballastless track with sound absorption board was 2 dB lower than that without sound absorption board; while noise on double- block ballastless track with sound absorption board was ldB lower than that without sound absorption board. Sound absorb effect of the board is good at the frequency from 315 to 3 150 Hz and can effectively absorb the sound energy between 500 and 4 000 Hz exhausted by a passing train. The paper also analyzed the reason of different sound absorb effect of the block. This research achievement might be used in the experience of railway EIA.