注浆控制土体变形原位试验与隧道竖向变形数值模拟研究

In-situ test of grouting control soil deformation and numerical simulation of tunnel vertical deformation

基坑开挖过程会在一定程度上引起邻近隧道竖向变形,然而目前针对注浆控制隧道变形的理论研究较为缺乏。为了深入研究注浆引起的土体与隧道变形规律,探究更合理的变形控制措施,本文通过现场试验进行了注浆引起土体变形的研究,并对注浆对土体与隧道的影响进行了数值模拟和参数分析。原位试验结果表明,在刚结束注浆时,注浆产生的土体水平变形及超静孔隙水压力均是最大的,初期变形及超静孔隙水压力减小较快。分段注浆时,下方注浆完成之后,浆液更容易向上流动,使上方土体产生较大变形。距离注浆体位置较近的土体竖向位移衰减得较快。数值模拟结果表明,在相同的位置注等量浆液,由于隧道的刚度相较于土体更大,土体变形远大于隧道变形。注浆后浆液大部分向上流动,难以对下方的土体/隧道产生变形影响。

The foundation pit excavation may cause vertical deformation of adjacent tunnels to some extent.However,there is a lack of theoretical research on grouting to control tunnel deformation.To gain a comprehensive understanding of the deformation behavior of soil and tunnels caused by grouting and to explore more effective deformation control measures,a field test was conducted to investigate the soil deformation induced by grouting and the influence of soil and tunnels resulting from grouting was simulated.The test results show that,the largest horizontal deformation and excess pore water pressure of soil caused by grouting achieved at the end of grouting;while the deformation and excess pore water pressure decrease rapidly in the beginning.During segmented grouting,after the grouting at the lower part is completed,the slurry tends to flow upward,resulting in large soil deformation at the upper part.The vertical displacement of soil close to the grouting body ttenuates faster.Furthermore,numerical simulation results demonstratethat when the same amount ofslurry is injected at the same position,the soil experiences significantly greater deformation compared to the tunnel.After grouting,a substantial portion of the slurry flows upward,which leads to the reduction of potential impact on the deformation of the soil/tunnel below.