Fig. 4

Temporal changes in temperatures and water pressures for the borehole and four outlet faces, and AE energy at 1 mL/min (a1–a3), 5 mL/min (b1–b3), 10 mL/min (c1–c3), and 15 mL/min (d1–d3) in Run 1. σ_x (y) in the middle row demotes the pressure for the outlet face, y (R: right face, L: left face, F: front face, B: back face) subjected to the principal stress, σ_x (x: 1, 2, 3)