Abstract

The behaviors of the ground in crossed zone and the existing upper tunnel in shallow cover due to the excavation of new lower tunnel crossed to that was studied. Model test was performed in the large scale test pit, the size was 4.0m (width)×3.8m (height)×4.1m (length)'. Test ground was constructed uniformly by sand in middle density and test with the crossed angle of 56 (obliquely) were performed. The numerical analysis was performed on equal condition with model test. Results of the study by model test and numerical analysis show that earth pressure and settlement of the ground in crossed zone were redistributed due to the longitudinal arching effect by the excavation of lower tunnel. Model test shows that upper tunnel blocks stress flow due to the longitudinal arching effect by excavation of lower tunnel.