基于正交分析的地铁目标频段隔振排桩参数研究

Study on the Parameters of Periodic Pile Barriers for Vibration Isolation within Target Frequency Range of a Subway Based on Orthogonal Analysis

为优化地铁目标频段隔振排桩设计与选型,基于带隙理论和正交分析理论,针对桩长、排数、列数、隧道埋深以及排桩到隧道距离等因素对振动衰减效果的影响规律展开研究。研究表明,在粉质黏土地层条件下:(1)各因素对竖向振动衰减影响主次排序:隧道埋深>桩长、排数>列数>排桩到隧道距离;(2)各因素对水平振动衰减影响主次排序:排桩到隧道距离>隧道埋深、排数>桩长>列数;(3)为取得较好的竖直方向衰减效果,隧道埋深<0.8λ_(SV)时(λ_(SV)为土体剪切波波长),桩长宜取3.2λ_(SV);隧道埋深介于1.6λ_(SV)~2.4λ_(SV)时,可在1.6λSV~3.2λ_(SV)和4λ_(SV)~4.8λ_(SV)范围内增加桩长;排数达到3排就能取得较为稳定的隔振效果。

In order to optimize the design and selection of periodic pile barriers for vibration isolation within target frequency range of the subway,this paper studies the influence of pile length,row number,column number,tunnel buried depth and the distance between piles and tunnel on the vibration attenuation effects based on the band gap theory and the orthogonal analysis theory.Researches show that,on the condition of silty clay stratum:(1)The primary and secondary order of the influencing factors on the vertical vibration attenuation effect within the initial complete bandgap is:tunnel buried depth>pile length,row number>column number>distance between periodic piles and tunnel;(2)The primary and secondary order of the influencing factors on the horizontal vibration attenuation effect within the initial complete bandgap is:distance between periodic piles and tunnel>tunnel buried depth,row number>pile length>column number;(3)In order to achieve good vertical vibration isolation,when tunnel buried depth is less than 0.8λ_(SV),pile length should be 3.2λ_(SV);when tunnel buried depth is between 1.6λ_(SV)~2.4λ_(SV),pile length can be increased in the range of 1.6λ_(SV)~3.2λ_(SV) or 4λ_(SV)~4.8λ_(SV);when row number reaches 3,stable vibration isolation can be achieved.