Optimization Of Fracture Repair Materials And Grouting Simulation Study Of Soil Site

With a civilisation of five thousand years,China has a long history and culture,and there are numerous precious earthen sites scattered throughout its territory.These sites are of great historical,scientific and social value.They are distinctive in that the main building material is earth and the building masses are large,most of which are in open-air conditions and subject to significant environmental influences.The current state of survival of most of these sites is not promising,with serious damage and urgent restoration,making it important to undertake restoration research on earthen sites.Considering that fissures are the most common and influential disease on earthen sites,this paper focuses on the restoration of fissures on earthen sites in loess areas,with restoration materials and methods as the main research objectives,and selects a variety of natural and environmentally friendly materials for the modification of restoration soils.Firstly,the materials were modified with soil alone,and then the better materials and proportions were selected for the mixing test,and then the environmental durability test of the mixed modified soil was combined with the final selection of suitable materials for fracture repair of soil sites.On this basis,COMSOL software was used to simulate the effect of different parameters on the effect of fracture grouting at the soil site,and the main findings are as follows:The site soil modification tests showed that for the single-mix tests,the selected modified materials all improved the cohesion and internal friction angle of the soil,with the most significant improvement in the modified soil with 6% natural hydraulic lime alone;for the mixed-mix tests,mixing the restoration materials with the ash generally gave better results than the single-mix,with the highest strength and the greatest improvement in the modified soil with a 10% blast furnace slag and 1:9 ash mix.The durability test of modified soils showed that in the freeze-thaw test,the strength of all modified soils decreased with the increase of freeze-thaw times,with the most significant decrease in the first 10 times,among which the loss of cohesion and internal friction angle of the partial metakaolin-lime modified soil in the first 10 times were 68.7% and 77.1% of the total loss,respectively;in the immersion disintegration test,the loess samples basically lost strength after soaking for about 5 min,while In the dipping shear test,the strength of the modified soil was greater than that of the loess,and the loss of cohesion and internal friction angle of the slag-lime modified soil was 29.1% and 20.47% respectively;in the scouring test,the loss of the surface of the partial metakaolin-lime modified soil and the slag-lime modified soil was the least;in the saline erosion test,the strength of the salt-doped specimens all In the saline erosion test,the strength of the salt-doped samples decreased to a certain extent,while the strength of the alkali-doped samples remained the same or increased slightly,except for sodium alginate,which was unstable in the alkali environment and caused a decrease in strength.The results of these tests show that the modified soil with 8% metakaolin and 10% slag mixed with 1:9 grey soil has the best performance in terms of strength and durability and can be used as the first choice for crack repair in soil sites.In the grouting simulation study,the diffusion of slurry in the fractures of the soil site was calculated and analysed for different water to ash ratios,grouting pressures and fracture widths.The results show that the water to ash ratio has the most significant effect on the slurry diffusion,the grouting pressure has a slight effect,while the fracture width has a minimal effect on the slurry diffusion.This paper has carried out experiments and simulations on materials and methods for the repair of fissures in earthen sites,selected suitable repair materials,analysed the factors and laws affecting the diffusion of grouting,and the research results can provide reference and basis for the conservation and repair of earthen sites,with good practical significance and application value.