Experimental Study On Static Properties Of Fiber-reinforced Soil Subjected To Freezing And Thawing

As a kind of soil improvement means,fiber-reinforced soil was widely used in various special subgrade soils.With the speed of China’s infrastructure construction,this means of soil improvement began to be applied to seasonal frozen ground.In view of the requirement for the strength,stiffness and stability of the subgrade fillings in the seasonal frozen soil area,the actual improvement effect of the fiber-modified soil in the seasonal frozen soil area needs to be systematically verified.In this paper,the silty soil in seasonal frozen soil is taken as the research object,and the modified triaxial test is carried out under the condition of freezing and thawing cycles,and the mechanical properties and deformation properties of the silty soils modified with polypropylene fiber are tested.The influence of various factors on the deformation and mechanical properties was analyzed.The main research contents and research results include:(1)Polypropylene fiber-reinforced soil relative mechanical properties and antifrost heave and thawing performance reinforced significantly,polypropylene fiber in the seasonal frozen soil roadbed filler improvement can play its due role.(2)Confining pressure,fiber content,fiber length can improve the strength of the sample index.It was found that the fiber content and length had a significant effect on the cohesion of the sample,and the effect of the freeze-thaw cycle was relatively small.The fiber content,the fiber length,and the number of freeze-thaw cycles do not have much effect on the internal friction angle of the sample.5 ‰ fiber content of the sample strength of the highest,but there are many samples under the content of the strength will be reduced and the existence of weak rupture surface problems.So the 3 ‰ fiber content,9mm and 12 mm fiber length of the sample stability and economy is ideal.(3)It is found that the fiber content has a great influence on the specimen.The effect of fiber length is not obvious and there is no specific rule.3 ‰ fiber content of the sample showed good anti-freeze-thaw performance,6mm and 9mm fiber length of the sample frost heave melt displacement is smaller.(4)Combining the frost heaving and melting properties of polypropylene fiberreinforced soil,the optimum dosage and length are combined.