| In recent years,with the vigorous development of the national infrastructure construction projects,a number of areas of underground engineering,construction engineering,water conservancy and other rapid development,continues to expand the scale,but the project is increasing,the most common is the complicated stratum of rock mass seepage plugging and foundation reinforcement.At present,the solution of this kind of engineering problems mainly depends on grouting technology.Asphalt grouting is a new fast plugging technology developed in China recently.It belongs to chemical grouting category in a strict sense.The principle of asphalt grouting mainly depends on the physical properties of asphalt,so as to achieve the purpose of grouting.Asphalt materials and water immiscible,when the asphalt is heated into the flow of liquid,changing the shape of the asphalt material,has good fluidity and pumpability,dispersed asphalt slurry into the leakage water,with water flowing into the leakage passage,after cooling the asphalt adhesion in the seam wall gradually the channel,not easy to be out of water.With the continuous accumulation of asphalt on the seam wall,the water seepage channel shrinks until finally completely blocked,so as to achieve the purpose of strengthening and strengthening the rock and soil,and preventing leakage.This paper aims at the defects of the existing asphalt grouting materials and shortcomings,especially for the research of modification of existing asphalt grouting,based on the full use of the existing data collection,through the indoor experiment,firstly from the aspects of asphalt modification,preparation of a liquid asphalt can have greater mobility at room temperature the long time and can maintain its morphology and properties do not change.Then,the solidified material is added into the prepared normal temperature liquid asphalt,and the mixture is mixed with the liquid asphalt,so that the liquid asphalt at normal temperature can be condensed and solidified,so as to achieve the purpose of seepage prevention and leakage prevention and reinforcement.According to the different types of curing agent,initiator,accelerator and diluent content,design of multi group formula,each formula respectively when the initial pumping period,and condensation time determination of viscosity of slurry,determination of compressive strength,bond strength and consolidation strength after solidification,the optimum formula can meet the grouting conditions.Finally,the optimum formula of materials and ordinary cement slurry test to select the different head flow under different porosity under dynamic water erosion simulation test,comparing the two kinds of slurry fluidity,permeability,fluid retention and erosion intensity,a comprehensive evaluation of the modified asphalt slurry grouting performance.The main research contents and results are as follows:(1)Through many experiments,adding 15% solvent 0# diesel and 2%R in asphalt heating and melting of modifier,stirring and dissolving,cooling the asphalt no longer return to solid,but showing a liquid with certain flowability,successfully developed liquid asphalt.This provides precondition for asphalt grouting to save heating,save time and effort,and improve construction efficiency.(2)In normal temperature curing liquid asphalt test,combined with the initiator with 4 types of curing agents in different dosage ratio,influence on slurry condensation indexes during the curing process,the test results should be used as initiator and B curing agent combination system,and the dosage of initiator and B curing agent should be 30% of liquid asphalt.(3)The diluent has some influence on initial viscosity of slurry and mechanical properties of grouts.If the amount of admixture is too small or too large,the mechanical properties of slurry consolidation will decrease,so the amount of diluent should be controlled within a certain range.(4)The accelerator has an important influence on the coagulation and solidification rate of the slurry.Considering the slow curing and the homogeneous polymerization of the slurry,it is recommended that the dosage of accelerator should be 2% of the initiator without affecting the follow-up work.(5)In the anti-scour simulation test,the retention rate of asphalt slurry and cement slurry is decreased with the increase of porosity.The retention rate of asphalt slurry was kept above 70%,while the retention rate of cement slurry was even lower than 60%,which indicated that the water resistance of asphalt slurry was better than that of cement slurry.Under the condition of the same porosity,the retention rate of asphalt material is higher than that of cement slurry 10%~20%,which shows that the asphalt slurry is better than ordinary cement slurry.(6)The asphalt slurry can effectively penetrate into the rubble and broken stone clearance,firmly adhesion wrapped together,show that the asphalt material permeability and good fluidity;in water flow increases,asphalt slurry along the trough bottom began to spread,suggesting that the bitumen slurry diffusion is good;the ordinary cement slurry in dynamic water scouring before and after the basic surface covered with gravel body,show that the cement slurry fluidity than asphalt slurry,lower asphalt slurry diffusion.(7)After the erosion test,the asphalt slurry has been completely solidified and solidified,and the slurry wrapped up the crushed stones to form a dense and solid network structure,which joined together to form a whole organic body of higher strength.The cement slurry is not solidified because of the hydration reaction too slowly.The cement slurry and the crushed stone are not cemented together and the surface is separated.Compared with asphalt grouting material,cement slurry to quickly reinforce plugging effect in practical grouting engineering.In summary,modified asphalt grouting material test system has the advantages of low viscosity,good permeability,diffusion resistance,fast curing,high strength,consolidation of water scouring resistance,provides new ideas for the treatment of hydrodynamic conditions of rock and soil,seepage prevention and reinforcement of the strong complementarity problem,has application value important. |
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