Abstract: In order to reveal the influence of aggregate size effect on the improvement effect of expansive soil, iron tailings sand and calcium carbide slag were selected as amendments to treat expansive soil. The unconfined compression strength, water stability and stress-strain characteristics of the improved soil with different aggregate sizes(0,2) mm, [2,5) mm and [5,10) mm) were studied, and its structural changes were analyzed in combination with microscopic experiments. The experimental results show that the larger the aggregate size of the improved soil, the lower its unconfined compression strength and water stability, the smaller its stiffness, and the more obvious its brittle failure characteristics. Compared to the improvement by using iron tailings sand, the composite improvement effect is better. The addition of iron tailings sand can weaken the negative impact of aggregate size effect on the improvement effect, and the optimal dosage is 30%-40%. Calcium carbide slag is enriched on the surface of the aggregates, causing the soil sample structure to become loose. At the same time, the internal soil modification effect is poor, which has a negative impact on the stability of the sample. Adding iron tailings sand can fill the pores between the aggregates, improve the pore structure of the soil, and increase the strength of the soil sample. The experimental results can provide reference for the application of iron tailings sand and calcium carbide slag in expansive soil improvement engineering.
Keywords: expansive soil improvement; aggregate size effect; industrial waste residue; unconfined compression strength
合肥工业大学学报自科版