This paper develops a model that only requires two sets of small-size rock specimens with the ratio of the structural geometry parameter maximum to minimum a_e,max:a_e,min ≥ 3:1 to determine the rock fracture and strength parameters without size effect and predict the actual structural performance of rock. Regardless of three-point-bending, four-point-bending, or a combination of the above two specimen types, fracture toughness K_IC and tensile strength f_t of rock were determined using only two sets of specimens with a_e,max:a_e,min ≥ 3:1. The values K_IC and f_t were consistent with those determined using multiple sets of specimens. The full structural failure curve constructed by two sets of small-size specimens with a_e,max:a_e,min ≥ 3:1 can accurately predict large-size specimens fracture failure, and ±10% upper and lower limits of the curve can encompass the test results of large-size specimens. The peak load prediction curve was constructed by two sets of specimens with a_e,max:a_e,min ≥ 3:1, and ±15% upper and lower limits of the peak load prediction curve can cover the small-size specimen tests data. The model and method proposed in this paper require only two sets of small-size specimens, and their selection is unaffected by the specimen type, geometry, and initial crack length.

本文开发了一种模型，只需要两组结构几何参数最大值与最小值a _e,max : a _e,min  ≥ 3:1 的小尺寸岩石试件即可确定无尺寸的岩石断裂强度参数影响并预测岩石的实际结构性能。无论是三点弯曲、四点弯曲还是上述两种试样类型的组合，岩石的断裂韧性K _IC和抗拉强度f _t仅使用两组试样来确定，_e,max为：a _e,min  ≥ 3:1。值K _IC和f_t与使用多组样本确定的一致。两组a _e,max : a _e,min  ≥ 3:1 的小尺寸试件构建的全结构破坏曲线可以准确预测大尺寸试件的断裂破坏，曲线上下限±10%可以包括大尺寸试样的测试结果。峰值载荷预测曲线由两组试件构成， _e,max : a _e,min ≥3:1，峰值载荷预测曲线上下限±15%，可覆盖小尺寸试样试验数据。本文提出的模型和方法只需要两组小尺寸试样，它们的选择不受试样类型、几何形状和初始裂纹长度的影响。