Study On Fiber Reinforced Soil Shear Strength And Stability Of Embankment Slope

In recent years,the development of China’s transportation industry has been rapid,and the corresponding requirements for engineering structures have also become more stringent.Geosynthetics are widely used in various geotechnical structures.Fiber-reinforced soils provide their physical and mechanical properties to meet high engineering requirements.Research on the addition of reinforcement such as laths and grids to soil is mainly focused on improving the safety and stability of the overall structure.The addition of chopped fibers in the soil can improve the performance of the soil material,and The discrete nature of fiber doping makes the material as isotropic overall,which is different from lacing and other reinforcements.The researches on the mechanical properties of fiber-reinforced soils mainly focus on different forms of mix ratios,but the mechanisms on quantitatively exploring the reinforcing strength of fiber-reinforced composites have not been developed yet.silty clay is used as the base material,adding short-cut polyethylene fiber to the soil,and combines the single fiber pull-out test to further explore the influence of different influencing factors on the shear strength of the fiber-reinforced soil,according to the test results.The finite element analysis of the fiber-soil subgrade slope was carried out.The main research work carried out in the paper is as follows:(1)A pull-out test device was designed to measure the interfacial friction between fiber and soil.The obtained data provide an important basis for the analysis of the shear strength enhancement of the fiber soil.(2)Based on the pull-out test device,the time-history curves of the interfacial friction between fibers and soil under different influencing factors(sand-bearing rate,moisture content,fiber diameter,vertical pressure,compaction degree)were measured and different influences were obtained.(3)The direct shear test of polyethylene fiber soil under different mix ratios was carried out.A series of direct shear tests were carried out to determine the ability of polypropylene fiber with different lengths and different contents reinforced clay.The statistical work on the number of fiber at the failure surface of the direct shear test specimens was carried out to further describe the fiber reinforcement rule.Combined with the above laws,a better fitting formula for the increment of cohesion was proposed.(4)The fitting formula of the changing trend of the shear strength of the fiber soil under different influencing factors was obtained.According to the statistical analysis results of the interface fiber number,the mechanism of action of each influencing factor on the shear strength parameters of the fiber soil was identified.The influence of influencing factors on the enhancement effect was analyzed.(5)The finite element model of fiber soil slope was established.The safety factor of the slope was calculated by the strength reduction method.At the same time,the value engineering method was introduced to fit the value engineering coefficient under different parameter design by regression surface fitting to obtain a regression effect.Significant multivariate quadratic regression variance.(6)A series of direct shear tests were conducted to determine the numerical statistical characteristics of the shear strength parameters of the fiber and the soil.Using this as a benchmark,a subgrade slope finite element model was established and the reliability of fiber soil and prime soil was calculated.