| Soil site due to the particularity of its own building materials,coupled with its long-term sustained,natural factors and human factors,makes soil site repair protection of cultural relics in one of the most difficult,the survey found that the soil sites all over the world to develop different extent of disease and the deterioration,and even some soil site on the verge of collapse,an urgent need to repair protect.Of the specialty of the ruins of soil environment in kaifeng,the erosion of soil sites are more serious in kaifeng area damage,and in kaifeng area to protect the site has not yet formed a mature theoretical system and research methods for protection of site repair,technical maturity,therefore in kaifeng area soil site to carry out the repair protection and research is of important value and significance.Sodium methyl silicate,as a kind of organic material,shows good hydrophobicity and is widely used in building walls,gypsum and other fields,but little is known about the application of the site soil.Therefore,based on the good hydrophobicity of sodium methyl silicate,this paper takes the kaifeng Bridge site soil as an example to determine 4 types of 16 improved samples.Sodium methyl silicate solution containing 4%,6%,8% and 10% concentration was carbonized and cured for 3h,6h,9h and 12 h.Capillary water absorption test and immersion disintegration test were conducted to explore the improvement effect of sodium methyl silicate on the water quality of the soil in Kaifeng site.The internal morphology changes were analyzed by scanning electron microscopy to reveal the improvement mechanism.Combined with the existing conditions of kaifeng soil site,three restoration methods,mixing method,capillary osmosis method and negative pressure osmosis method,were proposed.Combined with the test results,the application scope of each method was analyzed and compared.The main research contents and conclusions are as follows:(1)Capillarity is an important factor that causes erosion and collapse of soil sites.In this paper,through capillary water absorption test,it is found that sodium methyl silicate can significantly change the capillary effect of site soil,and the improvement effect is related to the concentration of sodium methyl silicate and carbonization curing time.The specific conclusions are as follows: 8% concentration of sodium methyl silicate solution is preferred,because the capillary water absorption of the sample does not change much when the concentration increases from 8% to 10%.The carbonization curing time of 9h is preferred,and the capillary water absorption of samples with all concentrations is the least after 9h carbonization curing.Too long or insufficient time is not conducive to the improvement of the water quality of the site soil.The experiment shows that the capillary action of the site soil can be effectively improved by the appropriate concentration of sodium methyl silicate solution and carbonization time.(2)When the soil is immersed in water,it is easy to disperse,break and collapse.In this paper,through the immersion disintegration test,it is found that the incorporation of sodium methyl silicate can effectively improve the anti-disintegration performance of the site soil after immersion.Similarly,the improvement effect is related to the concentration of sodium methyl silicate and the curing time of carbonization.The specific conclusions are as follows: the modified samples with 8% and 10%concentrations of sodium methyl silicate have little influence on the carbonization curing time.No matter how much the carbonization curing time is,the samples do not collapse and their appearance is intact.The results show that the high concentration of sodium methyl silicate can effectively improve the resistance of the site soil to soaking water,and it is little affected by the curing time of carbonization.(3)The degradation of soil sites is different,so it is necessary to select appropriate restoration methods.Through the comparative analysis of restoration methods and test results,the following conclusions are drawn: mixing method can only be used for in-situ repair of soil sites and new soil sites due to the limitation of restoration technology.The capillary infiltration test shows that the penetration rate and depth of sodium methyl silicate are greatly affected by the volume and concentration of sodium methyl silicate.Therefore,the capillary infiltration method is suitable for soil site restoration with small volume and low water resistance requirements.Through the negative pressure infiltration test,it is found that under the negative pressure force,the penetration of sodium methyl silicate in the soil site can basically ignore the impact of the volume of soil site and sodium methyl silicate concentration.Therefore,the negative pressure infiltration method makes up for the shortcomings of the capillary infiltration method,and can be used in most of the soil site restoration projects.To sum up,mixing method is suitable for soil site repair engineering,while negative pressure infiltration method is used for in-situ repair engineering of soil site.(4)Scanning electron microscopy(SEM)can be used to study the morphologic changes of soil samples before and after soil particle analysis.In this paper,the internal microstructure by SEM scanning electron microscope,compared with soil specimen,the methyl sodium silicate modified site soil specimen,a certain change in microstructure,the decrease in the number of independent suspension of the soil particles,the connection between the soil particles become more,connecting closely,the corresponding internal porosity decreases,because the adsorption of poly(methyl siloxane membrane,Then agglomeration and connection occur on the surface of soil particles,forming a more complete hydrophobic film.On the one hand,the formation of water-repellent film reduces the capillary effect of site soil and the capillary water absorption;On the other hand,it strengthens the connection between soil particles and improves the anti-disintegration performance of the site soil after immersion. |
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