Research On The Influence Of The Mechanism Of Dustfall On The Surface Of Statues And Salt Transportation Of Capillary Water On The Diseases Of Statues

As a cultural treasure of the Chinese nation,statues and murals have been damaged by nature,man-made and atmospheric pollution for thousands of years,and the ground disease frequently occurs,which seriously endangers the preservation of cultural relics such as statues.The dust on the surface of the statue will form a"cumulative effect"for a long time,and the salt in the dust will also migrate in the ground layer,which aggravates the disease and corrosion of the statue ground layer in the process of capillary salt transportation.At present,there are many researches on the mechanism of capillary water and salt transportation at home and abroad,but there are few studies on the impact of dust on the statues’cultural relics,especially the joint effect of dust fall and the capillary salt transportation process in the ground layer has not been reported.This study combines the actual environment of the statues’cultural relics,through the experimental study of the effect of dust fall on the capillary salt transport mechanism in the ground layer,exploring the mechanism of the joint effect of dust reduction and capillary water and salt transport on the disease of the statue,which is of great significance to the protection of the statue.（1）The research on the mechanism of the influence of dust fall and water and salt migration on the ground of the statue shows that:1)During the migration test of dust falling in the ground test block:The conductivity and ion concentration in the sample show a trend of keeping constant first and then increasing with the increase of the height of the sample,the higher the relative humidity,the more serious the deliquescence of dust fall,and the greater the amount of migration of soluble salts in the sample during dust fall.2)In the joint migration test of dust reduction and water and salt（ultra pure water,KCl,Na₂SO₄,KCl and Na₂SO₄ solutions）:After being soaked by the migration solution,the dust will migrate in the sample,increasing the conductivity and ion concentration in the upper soil sample of the sample,the farther the place is from the dust,the more difficult it is for the salt in the dust to migrate,the change of relative humidity has little effect on the migration of salt in the sample during dust fall.3)When the migration liquid is a salt solution,since the capillary migration capacity of salt in the salt solution is much greater than that in dust fall,which causes the salt in the groundwater to accumulate in the upper layer of the sample,and the dual effect of the two makes the statue ground battle more serious damage;On the whole,when dust falls and a variety of migrating fluids work together,the amount of migration of the total amount of soluble salt in the dust fall in the sample is:KCl and Na₂SO₄>Na₂SO₄>KCl>capillary water.（2）The research on the influence of water vapor adsorption on the surface of the statue and the ground battle layer shows that:1)Research on the dynamic characteristics of moisture absorption and desorption:When the moisture absorption and desorption kinetics of the ground test block and the statue dust test block reach equilibrium,the moisture absorption and migration flux>the moisture release and migration flux of the test block;the moisture absorption and dehumidification cycle of the ground test block>moisture absorption and dehumidification cycle of the statue dust test block,dust has little effect on the moisture absorption and moisture migration flux of the test block;the moisture absorption kinetic curves of the ground test block and the statue dust test block are most in line with the double exponential model（R²>0.996）.2)In the isothermal moisture absorption and desorption test:The equilibrium moisture content of the ground test block and the statue dust test block both increase with the increase of relative humidity,the fitting of isothermal moisture absorption curves of the test blocks is most in line with the Peleg model（R²>0.998）,it shows that the adsorption process of the test block is gradually transitioning from low humidity to short-range adsorption mainly to high humidity mainly to capillary condensation;the equilibrium moisture content of the test blocks decreases with the increase of relative humidity,the fitting of the isothermal dehumidification curves of the test blocks is most in line with the quadratic polynomial model（R²>0.997）;the dust will deliquesce under the action of relative humidity,and the salt in the dust will migrate in the sample,the lower the position,the more difficult it is for the salt to migrate in the dust,the higher the relative humidity,the more serious the deliquescence of the dust,and the greater the amount of migration of the total amount of soluble salt in the dust within the sample.3)During the dry-wet cycle test:In the early stage of the test,the sample quality has a large range of changes,with the increase in the number of dry-wet cycles,the sample quality changes gradually tend to be flat;the moisture absorbed by the test block in a wet environment is greater than the moisture released in a dry environment,after the dry-wet cycle test,some moisture will accumulate in the sample,and the moisture will drive the salt migration in the alternate dry-wet environment,after repeated dissolution and crystallization of these salts,they cause serious disease and corrosion to the ground.The main conclusion of this research shows that the atmospheric dust on the surface of the statue is affected by the migration of water and salt in the ground layer and the change of the microenvironment in which the statue is located,the salt in the falling dust migrates within the ground,and these salts undergo repeated dissolution and crystallization to aggravate the disease and corrosion of the statue ground.In this regard,the relative humidity of the preservation of the statues and cultural relics can be controlled below 79%and the relative temperature and humidity environment can be constructed as much as possible,isolate the capillary water from the ground of the statue,increase the frequency of cleaning up the surface of the statue and other preventive measures,to effectively slow down the occurrence of draconine disease on the statue.