土体加固范围对既有盾构隧道轨道的影响分析

Influence analysis of soil reinforcement range on existing shield tunnels orbital

为分析不同拱顶、拱底和不同横向土体加固范围对既有盾构隧道轨道及轨道高差的影响规律,运用Midas-gts有限元软件结合现场施工,并基于已有盾构隧道施工扰动范围的影响机理,对广州市某盾构隧道斜穿11号线工程进行研究。结果表明:既有轨道的沉降值曲线呈V型,轨道高差曲线呈W型;在一定范围内,相比其他土体加固,横向土体加固对控制既有隧道轨道和轨道高差效果显著,且当横向加固为1倍盾构直径时,既有隧道轨道和轨道高差的控制效果最明显;既有隧道轨道的最大沉降值与拱顶、拱顶+拱底以及横向加固范围呈对数线性关系,与拱底加固范围呈线性关系;盾构隧道扰动范围大致为距既有隧道两侧1倍盾构直径范围,故对盾构隧道两侧土体加固1倍盾构直径,防止隧道结构产生较大变形。

In order to analyze the influences of different vault, arch bottoms and different transverse soil reinforcement ranges on the existing tunnel track and rail height difference, the Midas-gts finite element software was used in combination with the on-site construction, and based on the existing shield tunnel construction influence mechanism of the disturbance range, the project of a shield tunnel in Guangzhou obliquely crossing Line 11 was studied.The results showed that the settlement curve of the existing track was a"V"shape and the rail height difference curve was a"W"shape;Within a certain range, lateral soil reinforcement controls effect of the height difference between the track and the track was significant, and when the lateral reinforcement was 1 D(D was the shield diameter),the control effect of the height difference between the existing track and the track was obvious;The maximum settlement of the existing track and the vault, the vault + arch bottom and the lateral reinforcement range had a logarithmic linear relationship with the arch bottom reinforcement range;The shield tunnel disturbance range was approximately 1D from both sides of the existing tunnel;The disturbance range of the shield tunnel was roughly within 1D on both sides of the existing tunnel.Therefore, the 1D range of soil on both sides of the shield tunnel was reinforced to prevent large deformation of the tunnel structure.