PSI - Issue 18

Mikhail Eremin / Procedia Structural Integrity 18 (2019) 135–141

140

6

Mikhail Eremin / Structural Integrity Procedia 00 (2019) 000–000

Fig. 3. Loading diagram for the case of free sliding with marked stages of deformation - a, fracture patterns for di ff erent stages of deformation, matched with loading diagram - b, c, d.

5. Conclusions

Modern problems of geomechanics are strongly related to the study of mechanical behavior of rocks under di ff erent loading conditions. This requires the engineering sta ff to know the basic laws of rock behavior, and above all, strength and deformation characteristics. In recent years a large role has become given to numerical simulation, which expands the understanding of mechanical behavior of rocks. In comparison to the laboratory experiment, numerical simulation is capable of estimating di ffi cult states of internal stress, if all model parameters are validated in simple model cases. One of the most simple model cases is uniaxial compression which was simulated. This work reports rather qualitative study of deformation behavior of porous sandstone. However, almost all model parameters were chosen according to the available experimental data and justified physical ideas of rocks behavior. The results of numerical simulation (UCS and Young’s modulus) are in satisfactory agreement with statistical data reported by Farrokhrouz and Asef (2017). It is obtained that the mathematical model under development catches major behaviorial trends of rocks such as nonlinearity in the beginning of deformation, nucleation of cracks prior to the peak stress, softening behavior and turn to residual strength. Failure patterns suggest that porous sandstone specimens undergo the mixed mode of fracture, since both tensile and shear cracks occur. We haven’t discussed the conditions of crack nucleation in the previous section. Here we should provide an important concluding remark: even in the conditions of external compressive loading, structural