铁尾矿粉改良水泥土的强度与动力特性试验研究

为提高水泥改良土强度,验证尾矿粉能够起到对水泥土的增强效果,对已用水泥改良过的路基土,在尾矿粉掺入量不同的条件下,经改良后水泥土的强度特性,以及对被最佳掺量的尾矿粉改良后的水泥土,在围压和频率不同的条件下进行动力特性的试验研究,制备了不同尾矿粉掺量(0%、2%、4%、6%、8%、10%)的试验土样进行无侧限抗压强度试验和动三轴试验;试验结果表明:随着尾矿粉掺入量的增加,无侧限抗压强度先增大后减小,土的应力应变曲线先急剧增加达到峰值后逐渐趋于平缓.当尾矿粉掺量达到最佳时,分析不同围压和不同频率的条件下G/Gmax~γ、λ~γ变化规律.对于同一动剪应变幅,动剪模量比随围压的增加而增大.阻尼比随动剪应变幅的增大而增大,随围压的增大而减小.G/Gmax~γ、λ~γ关系受频率影响不太敏感,都集中于一狭小范围.该试验能够提高水泥土强度的尾矿粉最佳掺量为6%.

Experimental Study on Strength and Dynamic Characteristics of Cement Soil Modified with Iron Tailings Powder

In order to improve the strength of cement stabilized soil and verify the effect of tailing powder on strengthening of cement soil,subgrade soil improved with cement,under the condition of different amount of tailings powder,strength characteristics of cement soil after improvement,and the best amount of tailings powder after the improvement of cement soil, experimental investigation on dynamic characteristics under different confining pressure and frequency is carried out,the test soil samples with different tailings content (0%,2%,4%,6%,8%,10%)were prepared. Test results show that:With the increase of the amount of tailings powder,unconfined compressive strength increases first,then decreases. Stress-strain curve of soil increases sharply first,then gradually flatten when peak value is reached. When the amount of tailing powder is optimum,dynamic three axis test the relationship between dynamic shear modulus ratio,damping ratio and dynamic shear strain amplitude under different confining pressure and frequency is analyzed. For the same moving shear strain amplitude,the dynamic shear modulus ratio increases with increasing confining pressure. The damping ratio increases with the increase of the shear strain amplitude, which decreases with the increase of the confining pressure. The relationship between the shear modulus ratio,the damping ratio and the moving shear strain amplitude isless sensitive to the frequency,and is concentrated in a narrow range. The optimum dosage of tailing powder which can increase the strength of cement soil is 6%.