Study on compressive strength test and estimation model of fiber reinforced loess

To investigate the compressive strength characteristics of fiber-reinforced loess and develop a corresponding strength estimation model，unconfined compressive strength tests were conducted to analyze the effects of varying fiber content，fiber length，fiber fineness，and moisture content on the compressive strength of reinforced loess. Combined with scanning electron microscopy(SEM) tests，the reinforcement mechanism and macro-mechanical properties of the fiber-reinforced soil were analyzed from a microscopic perspective. The test results indicate that the compressive strength of fiber-reinforced loess increases with higher fiber content，greater fiber length，and reduced fiber fineness；within the studied fiber length range of 10 to 40 mm，fiber reinforcement was effective. When fiber content is below a critical level，increasing fiber length and reducing fiber fineness further enhance soil reinforcement. Based on the test data，a reinforcing parameter <italic>I</italic>_r was developed to quantitatively evaluate the reinforcement effect，and a strength estimation model for fiber-reinforced loess was established. This model can accurately estimate the compressive strength of fiber-reinforced loess. Comparison with experimental results verifies that the model has high prediction accuracy and practical application value.