Study on critical power-law singularity of brittle creep failure in deep hole-containing sandstone

Through the high stress creep test of hole-containing sandstone, the mechanical behavior and deformation response characteristics are analyzed, the critical power law acceleration behavior and parameter variation law are revealed, and the creep failure evaluation index is constructed. The results show that: (1) The creep behavior of hole-containing sandstone is strongly correlated with the load, compared with intact sandstone, εc and t0 are reduced by 1–47% and 9–61%, respectively. (2) Tension cracks appear in hole-containing sandstone, accompanied by particle spalling and hole deformation. The intact sandstone shows tensile-shear composite failure, with brittle sound and particle collapse and accumulation. (3) The stable creep stage (∆t)max, (∆ε)max and accelerated creep stage (∆dε2/dt2)max of hole-containing sandstone are significantly higher than those of intact sandstone. The creep transition stage (∆dε/dt)max is lower than that of intact sandstone. (4) In the power-law acceleration stage, β changes significantly and converges to − 1, which induces damage; the β of the hole-containing sandstone is 2–26% higher than that of the intact sandstone (< − 0.9), but the β of the former is more volatile. At the time of impending disaster (≥ 0.9tf), the (∆t/tf)max and (∆β)max of the hole-containing sandstone are 1.8–2.2 times and 1.3–14.3 times that of the intact sandstone, respectively. 5) Compared with intact sandstone (α < 2), the α value (α > 2) of hole-containing sandstone increases by about 5–19%. The hole-containing sandstone λ is positively correlated with the load and is significantly higher than the intact sandstone.