局部振动压实荷载对地铁车站结构开裂影响分析

Analysis of Influence of Local Vibratory Compaction Load on Cracking of Metro Station Structure

针对某地铁车站回填过程中主体结构局部开裂问题,基于动力分析方法,分析压路机振动压实荷载对车站局部开裂的影响。结果表明,动力分析与静力分析整体趋势均与现场监测结果相吻合,静力分析数据较现场监测数据大,而动力分析数据与监测数据整体更接近;名义振幅和振动频率是影响振动机压实荷载对地铁车站结构开裂影响的主要因素;基坑底部土体最大沉降差与车站顶板最大拉应力值和名义振幅呈正比,且随着振动频率的增加呈现出先增大后减小的趋势;当振动频率为10 Hz、名义振幅为1.8 mm时,车站顶板拉应力最大,可能使得车站顶板发生开裂。

Targeting the problem of main structure local cracking during the backfilling process of certain metro station,based on dynamic analysis method,the impact of road roller vibratory compaction load on station local cracking is analyzed.Results show that the overall trend of dynamic and static analysis is consistent with the field monitoring results.The static analysis data is larger than the field monitoring data,while the dynamic analysis data is closer to the monitoring data in gene-ral.The nominal amplitude and vibration frequency are the main factors affecting the impact of vibratory compaction load on the cracking of metro station structure.The maximum settlement difference of foundation pit soil is proportional to the maximum tensile stress value and nominal amplitude of station roof,showing a trend of first increasing then decreasing with the increase of vibration frequency.When the vibration frequency is 10 Hz and the nominal amplitude is 1.8 mm,the tensile stress of the station roof is the largest,which may lead to cracking of the station roof.