Mechanisms and effects of the water seepage environment on the deterioration of stone cultural relics

Water seepage can accelerate the deterioration of stone, but previous experimental studies often only focused on a single solution, ignoring the complexity of the natural water environment. In this study, sandstone samples from two strata of Leshan Giant Buddha were collected. Then the wet-dry cycle experiment was carried out using the prepared water seepage solution with a concentration equivalent to the on-site solution. The severity of sandstone deterioration followed the order of Na2SO4 > CaSO4 > water seepage solution > H2O. The water seepage solution caused less deterioration than did the salt solutions (Na2SO4 and CaSO4) at the same concentration. Sandstones with strong cementation deteriorated slower, which was attributed to the variations in the mineral cementation balance index (MCBI). Furthermore, the uniaxial compressive strength of sandstones was predicted based on nondestructive indices combined with random forest (R2 ≥ 0.97), providing a nondestructive assessment method for the preservation of stone heritage.