Experimental study on the mechanical properties of short-term creep in post-peak rupture damaged sandstone

The creep of rock is a slow stress adjustment deformation and an evolutional process of rock mass destruction. Therefore, rock creep plays a vital role in a variety of rock engineering. To reveal the creep properties of rock, the following work has been done. A series of triaxial creep tests has been conducted considering different low confining pressures. The creep curve is analyzed under different confining pressures, and the creep law of each stage is obtained. Many results were obtained for the influence of confining pressure on the instantaneous modulus of deformation, creep strain, creep rate and instantaneous strain. The proportion of the various stages of creep changes under different confining pressure. Due to the existence of confining pressure, the ultimate failure method of rock has also been affected. Creep data can then be fitted by the improved Nishihara model, revealing a good relationship. The conclusion of this paper can provide some significant guidance for rock engineering.