Experimental study on creep failure mechanism of artificially frozen sandstone of Luohe Formation after thawing

Abstract

With the construction of coal mines in western China, most inclined shafts need to pass through the weakly cemented water-rich sandstone stratum of Luohe Formation, and there are huge safety risks in conventional tunneling, so the freezing tunneling method is often adopted. After artificial freezing and thawing, the water-rich sandstone of Luohe Formation has significant creep characteristics, which has obvious influence on long-term safety and stability of inclined shaft. Based on uniaxial compression creep mechanics tests of defrosted sandstone of Luohe Formation at different freezing temperatures, a more concise nonlinear fractional order creep mechanics model of sandstone was established; the fractional creep mechanical model of defrosted sandstone is constructed, and test data and fitting curves are analyzed through comparison. The results show that: with the decrease of freezing temperature, the creep variable, creep rate and nonlinearity of sandstone in Luohe Formation increase after thawing, and the nonlinear fractional creep model can well simulate the creep process of defrosted Luohe Formation sandstone, and the model is simple and convenient.

Keywords

• luohe formation sandstone
• freezing method
• freezing temperature
• creep mechanics
• creep model