Failure mechanism of circlular tunnel supported by concrete layers under uniaxial compression: Numerical simulation and experimental test

•The failure behavior of rectangular pre-holed gypsum samples with interlayer concrete under uniaxial compression was experimentally and numerically investigated.•The results show that concrete length, concrete layer number, and concrete circumstance all have an effect on the crack growth trajectory.•With the increase in the number of concrete layers, the concrete's young modulus, fracture initiation stress, ultimate strength, and absorbed energy were all raised.•Numerical simulation outputs are in good accordance with experimental test results. Under this study, particle flow code modeling and experimental testing were used to examine the failure behavior of a pre-holed rocklike specimen including concrete interlayers in uniaxial compression. Rectangular pre-holed gypsum samples with interlayer concrete have been made specifically for this purpose. The sample's measurements were 150 mm*150 mm*50 mm, and the hole's diameter was 20 mm. Changes were made to the concrete's length, location, and number. There were 0 and 20 mm between the concrete layer and the hole. The lengths of the concrete were 50, 100, and 150 mm. 20 mm thick concrete was used. This complex was quantitatively tested and simulated under uniaxial loading circumstances. 13 experiments in all have been performed. The findings show that concrete length, concrete layer number, and concrete circumstance all have an impact on the crack growth trajectory. Two tensile fractures started in the hole wall while it was in the middle of the concrete layer and spread parallel to the loading axis until coalescing with the sample edges. By increasing the distance between the concrete layer and the hole, more tensile cracks and oblique fractures occurred. By lengthening the concrete, the model's crack count was reduced. The shear bands at the hole were expanded by extending the distance between the concrete layer and the hole when the hole was encircled by two concrete layers. Additionally, by shortening the concrete, more shear bands were formed close to the hole. Longer concrete had higher young modulus, fracture initiation stress, ultimate strength, and absorbed energy. Additionally, the concrete layer's distance from the hole was increased, which diminished these mechanical qualities. By increasing the number of concrete layers, the concrete's young modulus, fracture initiation stress, ultimate strength, and absorbed energy were all raised. The results of the numerical simulation agree well with those o