Parametric Studies on the Interaction between Existing and New Bored Tunnels

摘要

The increase of underground tunnel infrastructure in urban cities implies a need to make rational andrnefficient use of underground space. Therefore, new tunnels in development areas have to bernconstructed more often in close proximity to the existing tunnels. Prediction of stresses induced in thernexisting tunnel is therefore crucial. This paper presents the results of a numerical study that has beenrnperformed to investigate the effect of new bored tunnels on the stresses induced in the lining ofrnexisting adjacent tunnels. The effects of tunnels relative position, tunnels proximity, Volume Loss,rndepth of burial and lining thickness have been studied in details. Observation of the resultsrndemonstrates that a new tunnel excavated above the crown of an existing tunnel would reduce thernbending moment in the lining of the existing tunnel. However, the bending moment will increasernsubstantially if the new tunnel is excavated beside the existing tunnel. The Volume Loss, depth ofrnburial and the lining properties have also been found to have a significant effect on the bendingrnmoment induced in the existing tunnel after interaction with the new bored tunnel. Therefore safetyrnand planning purposes can be affected by these factors.