Abstract：The property of Pisha-sandstone to be easily collapsed in water brings obstacles to water and soil treatment in the Yellow River Basin. In order to increase the utilization value of Pisha-sandstone, and reduce the cost of sediment treatment, an appropriate amount of cement and fiber was added to the Pisha-sandstone to improve its mechanical properties and functionality. Based on the reinforcement effect of basalt fiber(BF), the test block with 0.2%, 0.5% and 0.7% basalt fiber content was prepared. Unconfined compressive strength and SEM scanning electron microscope test were carried out. The effect of BF content and age on the strength of BF- Pisha-sandstone cement soil, and the formation mechanism of BF-Pisha-sandstone cement soil′s strength were explored and the stress-strain curve equation of BF participating in Pisha-sandstone cement soil was established. The results show that the incorporation of fiber effectively increases the strength of Pisha-sandstone cement soil, and its strength increases first and then decreases with the increase of BF. The peak strength is reached when the content is 0.2%; the later strength of BF- Pisha-sandstone cement soil is more obvious than that of Pisha-sandstone cement soil; the age of BF-Pisha-sandstone cement soil is positively correlated with the unconfined compressive strength, but is negatively correlated with its strength growth rate; Pisha-sandstone cement soil with a cement content of 10% and a fiber content of 0.2% can completely replace that with a cement content of 15%. At 28 days of age, the stress-strain curve equation of BF- Pisha-sandstone cement soil with BF content between 0 and 0.7% is established, which is convenient to reflect the stress-strain changes and failure conditions of each fiber content.
