地层差异对轨道减振效果影响测试分析

Field Test and Analysis of the Influence of Stratum Differences on the Performance of Track Vibration Reduction

研究目的:针对目前减振轨道减振效果现场测试评价中忽略地层因素影响的研究现状,本文通过现场测试量化地层差异对轨道减振效果评价的影响,提出具有显著影响的地层因素及规律,明确不同地层参照断面选取对测试结果的影响程度。研究结论:(1)本测试研究结果表明选取不同断面测试分析隧道壁对比损失时,地层差异能引起隧道壁分频振级对比损失结果最大相差10 d B以上,Z振级对比损失结果相差4 d B以上;(2)隧道壁壁后地层剪切波速和波阻抗对隧道壁对比损失影响较大,土体波阻抗为1.5~2倍关系时,隧道壁对比损失最大Z振级差值可超过3 d B;(3)地层剪切波速随深度增加时,对比工况埋深越浅,测试得到的隧道壁对比损失越大,获得的减振效果越好;(4)本研究成果可为减振轨道设计、工后评价提供参考和指导。

Research purposes:In view of the research status that the influence of stratum factors is ignored in the field test and evaluation of vibration reduction effect of vibration damping track,this paper attempts to quantify the influence of the stratum differences on the performance evaluation of track vibration reduction,put forward the stratum factors and laws that have significant influence,and make clear the influence degree of the comparative section selection with different stratum on the test results by field tests.Research conclusions:(1)The test results show that comparative loss difference of more than 10 dB vibration level related to the frequency and 4 d B maximum Z vibration level on the tunnel wall can be caused by the stratum differences when different test sections are selected to analyze the comparative loss on the tunnel wall.(2)The shear wave velocity and wave impedance of the stratum behind the tunnel wall have a great impact on comparison loss of the tunnel wall,and when the wave impedance of the stratum is the relationship of 1.5~2 times,the comparative loss difference of maximum Z vibration level on tunnel walls can exceed 3 dB.(3)When the shear wave velocity increases with the depth,the shallower the buried depth of comparative section is,the greater the comparative loss on tunnel wall is,and the better the test evaluation effect of vibration reduction is.(4)The research results can provide reference and guidance for the design and evaluation after construction of track vibration reduction.