Effect of Fiber and Fine Particle Content on Freeze-thaw Resistance of Straw Fiber Soil
In order to enhance the freeze-thaw resistance of straw fiber soils,corn straw and reed straw fiber with a length of 9 mm were mixed into muddy soil respectively.After different freeze-thaw cycles,unconfined compressive strength test and direct shear test were carried out.At the same time,the conventional test and freeze-thaw test on the influence of fine particle content on the strength of fiber soil were carried out,and the internal changes were deeply analyzed by electron microscope scanning.The test results show that freezing and thawing have significant influence on soil strength and cohesion,but little influence on internal friction angle.With the increase of freeze-thaw cycles,the soil is affected by frost heave effect,the soil particles are rearranged,the soil structure is destroyed,cracks are produced,and the strength and cohesion are reduced.After five freeze-thaw cycles,the soil structure is stable,and the strength and cohesion are also stable.Appropriate amount of fiber can obviously improve the frost resistance of soil.After freezing and thawing,comparing the mechanical properties of the two kinds of fiber soil,the strength of corn straw fiber soil is higher and the toughness of reed straw fiber soil is better.In addition to this,the fine particle content has a greater effect on the soil freezing and swelling sensitivity(frost heave properties),the higher the fine particle content is,the more pronounced the effect of freezing and swelling of the soil is,which leads to a substantial attenuation of the strength of the soil body.However,in the absence of freezing and thawing,the increase in fine particle content can instead improve the compressive strength of the soil.
straw fiber soilfreeze-thaw resistancemechanical testfine particle contentcompressive strengthshear strength index
万方数据
维普
