湿热盐与冻融作用下贺兰山岩画劣化机理对比研究OA

Helan Mountain rock art is one of the most representative and largest ancient rock art groups in northern China,and is currently facing severe weathering threats.Based on the climatic and environmental characteristics of the Helan Mountain rock art site,this study designed two sets of labo-ratory accelerated aging tests:hygrothermal-salt cycle and freeze-thaw cycles,and employed multi-scale analytical techniques such as SEM,XRD,porosity and permeability tests and nanoindentation to systematically compare the rock deterioration effects under two environmental stresses.The results indicated that the freeze-thaw cycle primarily caused microcrack propagation through physical mecha-nisms,resulting in relatively mild deterioration.The hardness and elastic modulus decreased by only approximately 3％and 1.3％,respectively,and limited changes were observed in porosity and perme-ability.In contrast,the test results of the hygrothermal-salt cycle showed that physicochemical syner-gistic effects,including salt crystallization pressure,cement dissolution,and clay mineral expansion,caused severe damage to the rock structure,with a 69％～86％increase in permeability,a 44％reduc-tion in hardness,and a 20.3％reduction in elastic modulus,as well as particle detachment.It was re-vealed that the essence of sandstone deterioration lay in the preferential dissolution,expansion and loss of cement-phase minerals under environmental stresses such as salt damage and frost heave,which led to a significant reduction in the bonding force between rock particles,instability of the micro-structure,and ultimately the degradation of macroscopic mechanical properties and surface spalling.This study suggests that periodic desalination and humidity control can be adopted to mitigate the weathering of rock art,thereby providing a theoretical basis and practical guidance for the scientific conservation of Helan Mountain rock art.