Modeling failure and instability of a single-jointed rock column based on finite deformation theory

The mechanical behaviour of rock columns is closely tied to factors such as joint development and height-to -width (H/W) ratio. Based on a recently developed finite deformation analysis scheme that can consider both material failure and structural instability of rock columns, uniaxial compression numerical tests of different H/W ratio rock columns containing a single-filled joint were carried out. It analyzes the effects of the strength of joint -filled material (joint strength) and H/W ratio on strength characteristics and failure modes of rock columns. The numerical results indicate that the joint strength controls the joint failure degree, macro-strength, stress distribution, and failure zone range of the rock column. Under different H/W ratios, the macro-strength of the rock column increases in an S-shaped curve with the increase in joint strength. Lower joint strength will accelerate joint failure, resulting in the failure mode of the rock column being joint failure-induced structural instability. As the joint strength and H/W ratio increase, the failure mode of the rock column evolves into the mode of cooperative material-structure-induced collapse and finally develops into structural instability-induced material failure. The research results have a particular reference significance for selecting grout materials for columnar jointed rock mass engineering.