Ground arching induced by the non-uniform ground deformations
When a tunnel is excavated, the ground above tunnel crown can be loosened and ground arching can be developed. And their size and shape would be dependent on the ground deformation characteristics and the distribution shape of local ground deformations. Terzaghi showed that the ground arching was developed due to the uniform ground deformations in the trap door tests. In this study, the development of the loosened ground zone and the ground arching depending on the distribution shape of local ground deformations were experimentally studied. For this purpose, model tests were performed in three types of ground deformations, and their results were compared to that of Terzaghi’s trap door tests, which were performed for the uniform local ground deformations. As a result, it was found that the loosened ground zone and the ground arching were developed in different shapes depending on the distribution shape of local ground deformations.