地铁车站洞桩法施工引起的地层变形及地表沉降预测  

Prediction of Strata Deformation and Surface Settlement Caused by Hole-pile Construction at Subway Station

作　　者：李健学 LiJianxue(China Railway 19 Bureau Group Rail Transit Engineering Co.,Ltd.,Beijing 101300,China)

机构地区：[1]中铁十九局集团轨道交通工程有限公司,北京101300

出　　处：《市政技术》2023年第12期102-110,共9页Journal of Municipal Technology

摘　　要：为了预测贵阳某地铁车站洞桩法施工引起的地表沉降,采用现场实测数据与数值模拟计算结果对比分析的方法,研究了不同导洞开挖顺序引起的地层变形规律,进一步根据现场实测数据及工程地质条件,依据洞桩法独特的结构形式优化了Peck公式,使其可用于预测砂层地质地铁车站洞桩法施工引起的地表沉降。研究结果表明:“先上后下,先边洞后中洞”开挖方案最优,对地表沉降影响最小;在洞桩法施工过程中,相邻导洞开挖表现出“群洞效应”,导洞开挖及扣拱施作引起的地表沉降量占总地表沉降量的比例为90.4%,其中导洞开挖对地表沉降影响最大;距车站中线-20~20 m范围为地层主要影响区,距车站中线-60~-20 m和20~60 m为地层次要影响区,需要对主要影响区土体采取加固措施;当最大地表沉降量修正系数α和沉降槽宽度修正系数β取值分布在0.44~0.66和1.38~1.69区间时,优化后的Peck公式预测地表沉降量与实测地表沉降量更加吻合。In order to predict the surface settlement caused by hole-pile construction of a subway station in Guiyang,the method of comparative analysis of field measured data and numerical simulation results was used to study the strata deformation law caused by different excavation sequences of pilot tunnels.According to the field measured data and engineering geological conditions,the Peck formula was optimized by the unique structural form of the hole-pile method to predict the surface settlement in the sand layer.The results show that"first up and then down,first side hole and then middle hole"is the best excavation scheme,which has the least influence on surface settlement;During the construction process,the"group hole effect"appear in the excavation of the adjacent pilot tunnel.The surface settlement caused by the excavation of the pilot tunnel and the construction of the buckle arch accounts for 90.4%of the total surface settlement.The excavation of the pilot tunnel has the greatest influence on the surface settlement;The area with range of-20~20 m from the station central line is the main influence area of the strata,the-60~-20 m and 20~60 m from the station central line are the secondary influence areas of the strata,so that the main impacted area should be reinforced;When the maximum surface settlement correction coefficientαand the settlement trough width correction coefficientβare distributed in the range of 0.44~0.66 and 1.38~1.69,the surface settlement pre-dicted by the optimized Peck formula is more consistent with the measured one.

关 键 词：地铁车站 洞桩法 地层变形 地表沉降预测 现场监测 PECK公式 

分 类 号：U231.4[交通运输工程—道路与铁道工程]