Physical modelling of deformation and failure mechanisms and supporting effects for a deep-buried tunnel in inclined layered strata

In this paper, two physical model tests were conducted to study the deformation failure mechanism of a deep-buried tunnel in inclined layered strata and supporting effects with constant resistance and large deformation of anchor cables. The non-contact deformation and displacement test system, the strain data acquisition system, and the camera were applied to obtain the deformation and failure process of surrounding rocks and the vertical and transverse strain fields during the test. The results of the research showed that when the tunnel was excavated in the inclined thin-layer rock strata, the deformation had obvious asymmetry, the left arch shoulder of the tunnel presented bending fracture failure, the right arch shoulder presented shear slip failure; the key position of the failure was located in the left arch shoulder of the tunnel. When the asymmetric constant resistance and large deformation anchor cable model was used, the strain field was transferred to the deep rock strata, and the deformation coordination of deep and shallow rock strata was realized. The deformation and strain field of surrounding rocks was significantly reduced.

Automated summary

In this paper, two physical model tests were conducted to study the deformation failure mechanism of a deep-buried tunnel in inclined layered strata and the supporting effects of constant resistance and large deformation anchor cables. The deformation and failure process of surrounding rocks and the strain fields were obtained using non-contact deformation and displacement test system, strain data acquisition system, and camera. The results showed that the deformation of the tunnel in the inclined thin-layer rock strata was asymmetrical, with bending fracture failure in the left arch shoulder and shear slip failure in the right arch shoulder. The key failure position was located in the left arch shoulder of the tunnel. When using the asymmetric constant resistance and large deformation anchor cable model, the strain field was transferred to the deep rock strata, achieving deformation coordination between deep and shallow rock strata and significantly reducing the deformation and strain field of surrounding rocks.