尾矿制备气泡混合轻质土的力学与抗冻性能研究

Mechanical Property and Frost Resistance of Foamed Mixture Lightweight Soil Prepared by Tailings

以尾矿制备气泡混合轻质土,研究了湿密度和尾矿质量掺量对轻质土力学和抗冻性能的影响,并研究了尾矿对轻质土气孔结构的影响。结果表明,气泡混合轻质土的抗压强度与湿密度成正相关,与尾矿掺量成负相关。当尾矿掺量达到45%(质量分数,下同)时,湿密度为700 kg/m^(3)和800 kg/m^(3)的轻质土抗压强度分别为0.97 MPa和1.40 MPa,相比未掺尾矿的轻质土强度分别下降约69%和66%。尾矿制备气泡混合轻质土具有良好的抗冻性,30次冻融循环中,湿密度为700 kg/m^(3)尾矿掺量为0%~45%的轻质土抗压强度损失率均在15%以内,且抗压强度均大于0.80 MPa,提高湿密度等级可以进一步改善轻质土的抗冻性。尾矿的掺入会导致轻质土孔隙率和平均孔径增大,孔圆度降低,相比于未掺尾矿的轻质土,当尾矿掺量达到30%时,孔隙率增大3.58%、平均孔径增大16.7%、圆度值增加7.4%。

The foamed mixture lightweight soil was prepared by tailings.The effects of wet density and tailings concent on the mechanical property and frost resistance of lightweight soil were researched,and the effects of tailings on the pore structure of lightweight soil were researched.The results show that the compressive strength of foamed mixture lightweight soil is positively correlated with wet density and negatively correlated with tailings content.When the content of tailings reaches 45%(mass fraction,the same below),the compressive strength of light soil with 700 kg/m^(3) and 800 kg/m^(3) wet density is 0.97 MPa and 1.40 MPa respectively,which is about 69%and 66%lower than that of lightweight soil without tailings.Tailings foamed mixture lightweight soil has good frost resistance.In 30 freeze-thaw cycles,the loss rate of compressive strength of lightweight soil with 700 kg/m^(3) wet density of 0%to 45%tailings is less than 15%,and the compressive strength is greater than 0.80 MPa.Improving the wet density grade can further improve the frost resistance of lightweight soil.The addition of tailings will increase the porosity and average pore diameter of lightweight soil and reduce the pore roundness.Compared with the lightweight soil without tailings,when the content of tailings reaches 30%,the porosity increases by 3.58%,the average pore size increases by 16.7%,and the roundness increases by 7.4%.