Experimental research on mechanical characteristics of iron tailings modified subgrade mixture under freeze-thaw conditions

Abstract

The amount of iron ore mining is increasing with the development of the country, and how to deal with the large amount of piled iron tailings slag has left a series of problems; if it can replace aggregates for road construction or save resources. On the one hand, it solves the problem of iron tailings slag occupying a large amount of land. This article explores the quality, strength and frost heave characteristics of the iron tailings modified roadbed mixture under freezing and thawing conditions. The limit compressive strength test and the frost heave and thaw settlement test are compared to obtain the influence law of the stress and strain characteristics, strength, frost heave and thaw settlement rate and quality loss of the iron tailings modified soil and the undisturbed soil. The results show that as the number of freeze-thaw cycles increases, the unconfined compressive strength of the iron tailings slag mixture gradually decreases, and stabilizes after 7 freeze-thaw cycles, and the gap between it and the undisturbed soil gradually decreases. The frost heave and thaw settlement test showed that the frost heave rate and thaw settlement rate of the iron tailings modified soil were lower than the original soil, and with the increase of the freezing and thawing times, the frost heave rate and the thaw settlement rate continued to decrease, and finally tended to 0. It is proved that under the freeze-thaw cycle, the frost heave performance and thaw settlement performance of the iron tailings modified soil are improved compared with the original soil, and the frost heave rate and thaw settlement of the iron tailings modified roadbed mixture with 3% cement The rates are all less than 3%, compared with the original soil before improvement, and the improvement effect is analyzed and evaluated.