摘要
地铁隧道在下穿既有铁路时,保证其安全运营是施工中的关键问题之一。为保证南京地铁S8线某段盾构隧道下穿宁启铁路桥涵的安全,通过建立FLAC三维数值模型进行计算分析,并将监测结果和计算结果进行对比分析,得出以下结论:1)盾构下穿期间,在对地层进行水泥注浆、加固土体的同时,还应加强同步注浆和二次注浆,设定施工控制区域,并将盾构施工参数精确到每一环。2)地层加固前后的地表变形规律,采取加固措施可以将地铁下穿带来的铁路沉降影响降至0.7 mm。3)根据现场情况制定了地表变形监测方案。结果显示,路基地表沉降较之桥涵沉降值显著一些,但仍处于安全范围之内。
A shield-bored running tunnel of Line S8 of Nanjing Metro crosses underneath existing Ni-Qi railway. It is of great importance to ensure the normal operation of the existing railway during the shield boring. In the paper,the deformation of the ground caused by shield boring is analyzed by means of FLAC 3-D numerical model,and comparison and contrast is made between the measured deformation and the calculated deformation. Conclusions drawn are as follows： 1） In addition to the grouting reinforcement made to the ground,simultaneous grouting and secondary grouting shall also be strengthened during shield boring,the critical control zones shall be established and specific shield boring parameters shall be determined for each segment ring; 2） Due to the ground reinforcement measures taken,the settlement of the existing railway caused by shield tunneling can be reduced to 0. 7 mm; 3） The monitoring result shows that the ground surface settlement of the subgrade of the existing railway is more serious than that of the bridge and culvert,but it is still within the limit.
出处
《隧道建设》
北大核心
2015年第10期1015-1021,共7页
Tunnel Construction
关键词
南京地铁
铁路
桥涵
路基
盾构
地基加固
监测
Nanjing Metro
existing railway
bridge and culvert
subgrade
shield
ground reinforcement
monitoring
