群洞施工邻近既有线深孔注浆加固范围研究

Research on the Deep Hole Grouting Reinforcement Scope during Group Tunnels Construction Adjacent to the Existing Line

为分析邻近既有线时深孔注浆对既有隧道变形的影响,并确定合理的注浆加固范围,以北京地铁17号线东大桥站邻近既有线隧道为工程背景,通过数值计算和现场实测分析在距离既有线一定区域进行全断面深孔注浆的加固效果。结果表明,在上层导洞与既有线高程相同,下层导洞小于既有线高程的情况下,下层导洞开挖是引起既有隧道变形的主要施工阶段,而上层导洞开挖对既有隧道的变形几乎没有影响,因此建议减小上层导洞的深孔注浆范围,重点加固下层导洞;随着深孔注浆范围的增大,既有线的竖向变形逐渐减小,但两者之间呈非线性变化关系,存在最优加固范围;当注浆范围大于10 m时,继续增加注浆范围对减少既有线变形的作用很小。

In order to analyze the influence of deep hole grouting on the deformation of existing tunnel in the process of adjoining it,and to determine the reasonable grouting reinforcement range,the Dongdaqiao Station of Beijing Subway Line 17,adjoining the existing Metro Line,was taken as the engineering background.The effect of full-section deep hole grouting reinforcement in a certain distance from the existing line was analyzed by numerical calculation and on-site measurement.The results show that the lower pilot tunnel excavation is the main construction stage that causes the deformation of the existing tunnel under the condition that the elevation of the upper pilot tunnel is the same as the existing line and the elevation of the lower pilot tunnel is smaller than the existing line,while the upper pilot tunnel excavation has little effect on the deformation of the existing tunnel.Therefore,it is recommended to reduce the deep hole grouting range of the upper pilot tunnel and pay more attention on reinforcement of the lower pilot tunnel.The vertical deformation of the existing tunnel gradually decreases with the increase of the range of deep hole grouting reinforcement,but the relationship between the two is nonlinear,and there exists the most optimal reinforcement range.There is little effect on reducing the deformation of the existing tunnel by increasing the grouting range when it is greater than 10 m.