Theoretical Study on the Initiation Model for the Kinked Open‐Crack Under Internal Hydraulic Pressure

The propagation and coalescence of the crack under hydraulic pressure is a common phenomenon in geotechnical engineering. First, based on the distributed dislocation technique (DDT), the theoretical solution of the full‐field stress complex potential functions for a kinked open‐crack in an infinite plane under far‐field compression and internal hydraulic pressure is derived. Second, the effects of the inclination angle α of the main crack, the inclination angle θ of the kinked segment, the ratio of l /2 c , the lateral pressure coefficient k , and the hydraulic coefficient λ on the stress intensity factors (SIFs) K I and K II at the tip B of the main crack and tip A of the kinked segment were investigated. Furthermore, the critical initiation angle θ c and critical hydraulic pressure P c were analyzed based on the maximum tangential stress (MTS) criterion. The results show that as α increases from 0° to 90°, K IA and θ cA first increase and then decrease, whereas the trends of K IIA and P cA are opposite. In contrast, K IB increases; K IIB , P cB , and θ cB first decrease and then increase. As θ varies from 0° to 90°, K IA and θ cA first increase and then decrease, K IIA increases, and P cA first decreases and then increases. K IB , K IIB , and θ cB decrease; P cB increases.