Study on mechanical properties of rock like samples with prefabricated holes under specific temperatures

Based on the volume shrinkage characteristics of expandable polystyrene (EPS) particles after heating, holes were randomly constructed in the interior of rock-like samples containing EPS particles after heating. The axial compression test was carried out on the rock-like samples, and then the failure process of samples with prefabricated holes under uniaxial compression was simulated by the particle flow software PFC2D. Therefore, the influences of diameter and porosity of precast holes on the mechanical properties, crack evolution and failure characteristics of rock-like samples were explored. The results show that the pore-forming effect in specimen was most evident under the heating of 200℃, which has a relatively small impact on the strength of the sample. The larger the pore diameter and porosity inside the sample, the lower the peak stress and the larger the peak strain, and even the strain mutation could appear. Moreover, the development of internal cracks in the sample is closely related to the pore diameter and porosity according to the results of PFC2D simulation. Furthermore, cracks generate firstly at the pore locations and then expand to the area surrounding the holes, and form a through crack ultimately. Besides, both tensile stress and shear stress play a significant role during the uniaxial compression failure process of the sample with pores, indicating that failure is not solely due to tensile stress. Although there are slight deviations between the stress-strain curves of indoor tests and numerical simulations, the overall trends are basically consistent.