Study on Strength Characteristics of Jet Straw Reinforced Loess

Adding fiber into soil can enhance the strength characteristics of soil, but it is mostly suitable for easy compaction conditions, and its application of complex conditions is limited. In this paper, preparation of jet straw reinforced loess samples by high pressure air injection, and direct shear tests were carried out to study the influence of fiber content and water content changes on the strength of the reinforced loess. In order to obtain the best mix ratio of reinforced soil under the required working performance, and based on the experimental data, the strength prediction model of reinforced soil under different working conditions is established. The results showed that: (1) The strength of soil presents a trend of "first increasing and then decreasing" to the increase of the content in straw fibe, and the addition of fiber can improve the failure mode of soil and enhance the residual strength and deformation capacity of soil; (2) The change of water content has a significant impact on the cohesion of the soil, but internal friction angle of reinforced soil with high fiber content is greatly affected, but the reinforced soil can still maintain good shear strength under high water content; (3) The decrease of water content is conducive to the reinforcement of fiber on cohesion and internal friction angle, with the decrease of water content, fiber increases soil strength lifting rate showed a trend of "decreasing first and then slowing down"; (4) The fiber content and water content are important factors affecting the shear strength, and the influence of water content should be given priority when predicting the strength; The research results have guided significance of optimizing the performance of reinforced loess, overcoming the blind area of application of fiber reinforced soil in engineering and scientific selection of corresponding design and construction methods.