Anisotropic strength and deformation of irregular columnar jointed rock masses under triaxial stress

Abstract

The special columnar jointed structure endows rocks with significant anisotropy, accurately grasping the strength and deformation properties of a columnar jointed rock mass (CJRM) under complex geological conditions is crucial for related engineering safety. Combined with the irregular jointed networks observed in the field, artificial irregular CJRM (ICJRM) samples with various inclination angles were prepared for triaxial tests. The results showed that the increase in confining pressure can enhance the ability of the ICJRM to resist deformation and failure, and reduce the deformation and strength anisotropic degrees. Considering the field stress situation, the engineering parts with an inclination angle of 30°–45° need to be taken seriously. Four typical failure modes were identified, and the sample with an inclination angle of 15° showed the same failure behavior as the field CJRM. Traditional and improved joint factor methods were used to establish empirical relationships for predicting the strength and deformation of CJRM under triaxial stress. Since the improved joint factor method can reflect the unique structure of CJRM, the predictive ability of the empirical relationship based on the improved method is better than that based on the traditional joint factor method.

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Central South University