Effect of Confining Pressure on Is(۵۰) Obtained by Point Load Test

In this investigation, the impact of confining pressure on the tensile strength obtained by point load test (PLT) is examined by particle flow code in two dimensions. In this regard, at first, a numerical model is calibrated using the Brazilian experimental test results. The tensile strength of the model material is equal to ۲.۵ MPa. Secondly, PLT is performed on the numerical models with dimension of ۱۵ cm × ۵۰ cm. The rectangular models are tested by PLT under the presence of the confining pressure. The loading rate is ۰.۰۰۱ mm/min, confining that the pressure is changed with the ۱۳ different values of ۰ MPa, ۰.۰۰۲ MPa, ۱MPa, ۱.۵ MPa, ۲ MPa, ۲.۵ MPa, ۳MPa, ۳.۵ MPa, ۴ MPa, ۵MPa, ۶ MPa, ۹ MPa, and ۱۱ MPa. The results obtained show that the vertical tensile crack develops through the model under a low confining pressure, while several shear bands are developed in the models under a high confining pressure. The number of shear cracks is augmented by augmenting the confining pressure. Is(۵۰) is the augment by augmenting the confining pressure. Also a new criterion is rendered in order to determine Is(۵۰) based on the confining pressure.

کلیدواژه ها:

Point load test ، PFC۲D ، tensile crack