盾构隧道近距离穿越燃气管道影响分析

Influence Analysis of Shield Tunnel Crossing Gas Pipeline at Close Distance

盾构隧道近距离穿越燃气管道易引起管道及周边地层变形,控制效果不佳可能引发工程事故。依托某盾构隧道长距离穿越燃气管道工程,采用ABAQUS建立盾构隧道掘进对管线影响的三维有限元模型,研究地表和燃气管道受力及变形,并对比分析下穿过程不同掌子面支撑压力和同步注浆压力对燃气管道沉降影响规律。结果表明,掌子面支撑压力增大,燃气管道沉降量随之小幅减小;盾尾同步注浆压力增大,燃气管道沉降显著减小,同步注浆压力控制在1.1~1.3倍静止土压力范围可满足燃气管道变形控制要求。经现场实测验证,燃气管道最大沉降速率仅为0.25 mm/d,小于变形控制标准。

Shield tunnel crossing gas pipeline at close distance is easy to cause deformation of pipeline and surrounding strata,and poor construction control may lead to engineering accidents.Based on a long-distance shield tunnel crossing gas pipeline project,a three-dimensional finite element model of the influence of shield tunnel excavation on pipeline was established by ABAQUS.The force and deformation of the surface and gas pipeline were analyzed,and the influence of different support pressure and synchronous grouting pressure on the settlement of gas pipeline was compared and analyzed.The results show that the settlement of gas pipeline decreases slightly with the increase of support pressure of tunnel face.After the synchronous grouting pressure of shield tail increases,the settlement of gas pipeline decreases obviously.It is proposed that the synchronous grouting pressure can meet the requirements of gas pipeline deformation control standard within the range of 1.1~1.3 times the static earth pressure.After field measurement and verification,the maximum settlement rate of gas pipeline is only 0.25 mm/d,which is less than the deformation control standard.