Simulation experiment study on large-size sandstone weathering under coupling effect of snow and temperature
Sandstone grotto temples are subject to varying degrees of weathering damage when exposed to freeze-thaw cycles.This study focuses on the North Grottoes in Gansu,employing a multi-faceted approach based on the coupled relationships of numerous environmental factors.Large-scale sandstone weathering simulations were conducted in a sophisticated multi-field coupling laboratory under conditions emulating snowfall-temperature variations.The findings reveal that repetitive snowfall-temperature fluctuations induce freeze-thaw cycles,causing significant microstructural changes in the sandstone.At the microscopic level,freeze-thaw cycles result in the nearly complete dissolution of surface sandstone cementation.Internally,the sandstone exhibits a degradation characterized by a predominant contact-type cementation breakdown,accompanied by a noticeable increase in pore volume and size.Macroscopically,there is a discernible augmentation in the depth of moisture infiltration,coinciding with a progressive expansion of damaged regions and an intensification in the severity of observed deterioration.Surface manifestations include warping,detachment,deepening discoloration,and widening of cracks.Mechanically,there is a gradual decline in strength.Moreover,a categorization of five distinct response-sensitive zones was established based on different sandstone rock types.This classification sheds light on the progressive cumulative weathering mechanism of sandstone under the influence of snowfall-temperature fluctuations.
rock mechanicssandstonegrotto templefreezing-thawing cyclessnowfall-temperature fluctuationscoupling of multiple variables and factorsweathering mechanism