Experimental Study on Reasonable Distance of Tunnels with Small Spacing
An experimental methods was used to study the reasonable distance of tunnels with small spacing, four tunnels were located in a model, the distances between them were 0.5D, 1.0D and 1.5D respectively. The results show that the stress is concentrated in the folder of rock due to the superimposed stress fields, intensive vertical cracks emerged in the folder rock, then folder rock buckled, finally, the crown area of the tunnel sank. The thickness of the folder rock is the crucial factor for the stability of the tunnel, when the thickness is less than 0.5D, the folder rock failed first, when the thickness is as much as the span of the tunnel, the individual dilapidated area in the folder rock will not intersected with each other, the middle area of the folder rock is still in a stable state, as a result, the folder rock can maintain in a stable state.
Qing Yang, Li Hua Zhu, Jing Jing He, Zeng Feng Yan and Rui Ren
X. M. Wen et al., "Experimental Study on Reasonable Distance of Tunnels with Small Spacing", Advanced Materials Research, Vols. 368-373, pp. 2621-2624, 2012