地铁区间浅埋暗挖施工的地表沉降特征

Study on Surface Settlements Induced by Bored Shallow Tunneling of Subway

通过大量现场监控量测数据的统计分析,研究在北京地区黏性土与砂性土互层的地质条件下地铁区间隧道浅埋暗挖法施工引起地表沉降的一般特征。结果表明:对于所考虑的17个北京地铁区间工点的现场监测数据,约有95.3%的最大地表沉降小于40mm,大于某沉降值的累计发生频率曲线符合正态分布;地表沉降槽宽度参数的取值范围为0.26～0.60;地铁区间隧道施工引起的地层损失率在0.19%～2%之间。

A regression analysis of the field measurements of ground surface settlements induced by bored shallow tunneling in Beijing subway was conducted to acquire empirical estimation of the relevant characteristic parameters. The ground includes silty sand, silty clay, clayey silt, silty time sand, medium and coarse sand, cobble and gravel, which present the typical soil composition in Beijing area. About 95.3% of the maximum surface settlements induced by tunneling were less than 40 mm. The accumulative frequency curve of maximum surface settlement fitted well with the accumulative normal distribution curve. The settlement trough width parameter was 0.26 -0.60. The ground loss ratio was 0.19% -2%. These results are useful for predicting the magnitude and influence range of ground surface settlement.