地铁隧道开挖超前小导管预注浆参数对地表沉降的影响

以哈尔滨地铁三号线湘江路站—会展中心站区间大断面地铁隧道暗挖段施工为背景,采用FLAC 3D数值模拟软件研究不同超前小导管预注浆参数下地铁隧道开挖引起的地表沉降规律,计算结果显示,改善小导管投影长度、注浆半径及径向加固范围这3个参数可以有效地减小地表最大沉降量。基于这3个敏感性因素设计正交试验,以掌子面后方14 m处截面最大地表沉降和掌子面处地表沉降释放率为评价指标,通过极差分析和方差分析得出:小导管投影长度对地表沉降的影响最为显著,其次是注浆半径,而小导管径向加固范围的影响最小。

Inf luence of Parameters for Pre-grouting with Advanced Small Duct on Ground Surface Settlement During Metro Tunnel Excavation

Taking the large section excavation of metro tunnel between Xiangjiang Road Station and Exhibition Center Station of Harbin Metro Line 3 as background,and using FLAC 3D numerical simulation softw are,this paper studied the law of ground surface settlement caused by metro tunnel excavation under different parameters for pregrouting with advanced small duct.The calculation results show that the maximum ground surface settlement can be effectively reduced by improving three parameters of advanced small duct,such as length along tunnel,grouting radius and reinforcement range in radial direction. The orthogonal experiment was designed based on these three sensitive factors.The maximum ground surface settlement of the section 14m behind the tunnel face and the release rate of ground surface settlement of the tunnel face were taken as the evaluation indexes.By means of range analysis and variance analysis,it is concluded that the length along tunnel of advanced small duct has the most significant inf luence on ground surface settlement,followed by grouting radius,w hile the inf luence of reinforcement range in radial direction is the least.