摘要
研究目的:黄土地区某城市地铁2号线盾构施工下穿既有陇海铁路线是一个盾构施工中的I级风险源,为保证地铁盾构施工安全下穿陇海线路,开展了盾构施工穿越既有铁路的变形控制技术研究,以为盾构安全施工提供技术支撑。研究结论:(1)黄土地区地铁盾构下穿既有陇海线路的地表沉降规律:不采取控制措施盾构施工时,路基右线隧道轴线正上方的沉降量为20.48 mm,左线隧道轴线正上方的沉降量为12.85 mm,左右线隧道的轴线上的沉降量均超出了沉降允许值;采取严格控制土压力、盾构匀速通过、严格控制注浆量、减少盾构推进方向的改变等减小地铁盾构下穿既有铁路施工风险的措施盾构施工时,右线隧道轴线正上方的沉降量为5.44 mm,左线隧道轴线上方的沉降量为4.95 mm,均小于变形允许值。(2)FLAC计算预测的变形规律与实际值基本一致,地表和铁路路基的变形量在允许范围内;减小地铁盾构下穿既有铁路施工风险的措施合理有效。(3)该研究成果可应用于黄土地区地铁盾构下穿铁路施工变形控制。
Research purposes： The shield construction of the Line 2 of the urban subway in loess area had to under - cross the Lianyungang -Lanzhou Railway and it was project with the I level risk. In order to guarantee the safe construction of the subway under - crossing the railway, the study was done on the deformation control technology for the shield under - crossing the existing railway for the purpose of providing the technical support for the safe shield construction. Research conclusions ： （ 1 ） The rule of the ground surface settlement for the loess subway shield across the existing Lianyungang- Lanzhou railway was forecasted by the FLAC3D numerical simulation analysis; when shield construction without control measures, the settlement of roadbed upward the right tunnel axial line is 20.48 mm, the settlement of roadbed upward the left tunnel axial line is 12. 85 mm, they are both beyond the allowable value; when shield construction with control measures for reducing the construction risk of the subway shield across the existing line, such as control earth pressure strictly, shield impelling in uniform speed, control the injected amount strictly, reduce the change of the shield impelling direction, etc, the settlement of roadbed upward the right tunnel axial line is 5.44 mm, the settlement of roadbed upward the left tunnel axial line is 4.95 mm, they are within the allowable value. （2） The result of the site monitoring indicates that the deformation rule forecasted by the FLAC accounting match with the true value basically, the deformation of the surface and the railway roadbed is allowed. The measures for reducing the construction risk of the subway shield across the existing line proposed is reasonable and effective. （ 3 ） The research results can be used in construction control of deformation for the loess subway shield across the railway.
出处
《铁道工程学报》
EI
北大核心
2013年第5期57-62,111,共7页
Journal of Railway Engineering Society
基金
高等学校博士学科点专项科研基金资助(20096121110004)
关键词
黄土地区
地铁盾构
穿越
既有铁路
变形控制
loess zone
subway shield
crossing
existing railway
deformation control
