深埋石英砂岩三轴分级蠕变特性研究

he time delay for rockburst is closely related to the creep mechanical properties of the surrounding rock in deep tunnel. Thus, the creep test for dry and saturated quartz sandstone under triaxial multistage loading was carried out. The results show that at the high stress level, the weakening effect of water on the rock is more obvious, which is faded by the restraint of confining pressure effect to slow down the creep failure process and improve the strength of the rock. In the dry state, the volume deformation of quartz sandstone presents a sawtooth wave evolution pattern compared to the saturated state. The weakening effect of water makes the volume expansion and deformation exhibit ductile characteristics in evolution process over time, while the confining pressure suppresses the deformation and compresses the adjustment space. The relationship between stress level and (log-) creep strain rate moves to the left as the water content increases, and moves to the right as the confining pressure increases. The dry and saturated rocks show failure modes in which shear dominates and shear and split coexist under uniaxial conditions, respectively. The dry specimen under confining pressure is still dominated by shear failure, while the saturated specimen tends to shear mode in the coexistence of shear and split failure. It may provide the reference for the generation mechanism, prediction and prevention of time delayed rockburst.