Influence of Foundation Pit Excavation on the Deformation of Tunnel Below and Its Countermeasures
The foundation pit excavation above the existing section tunnel is of great risk,its loading and unloading will change the original stress state of the section tunnel,resulting in additional stress and deformation.If the protection measures for foun-dation pit excavation are not properly controlled,the deformation of the section tunnel will inevitably exceed the limit,and even crack,water leakage and other diseases will occur.Taking the foundation pit of booster station above an interval tunnel as an example,combined with the existing state investigation results of the interval tunnel,finite element software midas GTS is used to conduct in-depth analysis on the impact of foundation pit partition,symmetrical construction and foundation pit backfilling conditions on the interval tunnel below.Research and actual monitoring datas show that during the construction of the upper foundation pit,some protection measures such as rational partition construction and symmetrical construction can effectively control the deformation of the tunnel below and ensure its structural safety,and the research can provide a certain reference for the construction of similar projects.
foundation pittunnel deformationmidas GTSsection tunnelpartition and blocksymmetrical construction