Determination and Application of Similar Materials in a Subway Excavation and Support Model Test

Abstract

In order to study the mechanical response of strata during the construction of a subway, it is crucial to develop similar materials suitable for indoor model tests. Therefore, based on the similarity theory, combined with the uniaxial compressive test results of similar materials, the similar materials and their ratios of advanced small pipes, shotcrete and steel frames were determined. Then, they were applied to the model test of a subway excavation and support. The variation laws of surface displacement, stress distribution around the tunnel and internal force of the steel frame during tunnel excavation and support were obtained to verify the reliability of similar materials. The results show that the aluminum arch frame with width of 4.87 mm and thickness of 5.00 mm can be used to simulate the grid steel frame. Nine fine steel wires in a ring are taken to simulate the advanced small pipes, and gypsum with elastic modulus of about 1.12 GPa are prepared to simulate the initial shotcrete. They are proven to accurately simulate the physical characteristics of supporting materials in practical engineering, and the variation is similar to that obtained from the field test, which improves the authenticity of the model test results.