不同外掺材料下泡沫轻质土力学性能试验研究

Experimental Study on Mechanical Properties of Foamed Lightweight Soil under Different Admixtures

摘要: 本文分别采用纯水泥，40%、50%、60%烧结法赤泥与25%、33%、40%粉质黏土制备泡沫轻质土，开展了无侧限抗压试验、劈裂抗拉试验、回弹模量试验以及软化系数试验。试验发现，泡沫轻质土抗压强度、劈裂抗压强度以及回弹模量均随水泥掺量减小而降低，且三者具有良好的线性关系；由于烧结法赤泥具有一定的胶凝活性，相同替代量下烧结法赤泥泡沫轻质土力学性能和软化系数均明显优于粉质黏土泡沫轻质土；40%~60%烧结法赤泥基泡沫轻质土的28 d抗压强度、劈裂抗压强度以及回弹模量分别为1.2~0.81 MPa、0.24~0.17 MPa和377~258 MPa；25%~40%粉质黏土基泡沫轻质土28 d抗压强度、劈裂抗压强度分别为2.43~1.02 MPa和0.44~0.2 MPa；不同类型泡沫轻质土软化系数均大于0.7。基于现有规范要求，提出以泡沫轻质土作为路床区填料，土替代量不高于33%，赤泥替代量不高于40%，以泡沫轻质土作为路堤区填料，土替代量不高于40%，赤泥替代量不高于50%。

Abstract: In this paper, pure cement, 40%, 50% and 60% sintered red mud and 25%, 33% and 40% silty clay were used to prepare foamed lightweight soil. Unconfined compression test, splitting tensile test, resilient modulus test and softening coefficient test were carried out. The experimental results show that the compressive strength, splitting compressive strength and resilient modulus of the lightweight foamed soil decrease with the decrease of cement content, and the three have a good linear relationship. Because of the cementitious activity of red mud, the mechanical properties and softening coefficient of the red mud foamed lightweight soil under the same dosage are obviously better than that of the silty clay foamed lightweight soil. The 28 d compressive strength, splitting compressive strength and resilient modulus of sintered red mud foamed light weight soil at 40% - 60% dosage are 1.2 - 0.81 MPa, 0.24 - 0.17 MPa and 377 - 258 MPa respectively. The 28 d compressive strength and splitting compressive strength of 25% - 40% dosage silty clay foamed light weight soil are 2.43 - 1.02 MPa and 0.44 - 0.2 MPa respectively, and the softening coefficient of different types of foamed lightweight soil is greater than 0.7. Based on the existing code requirements, it is proposed that foamed light soil should be used as roadbed filler, the soil content is not higher than 33%, red mud content is not higher than 40%, foamed lightweight soil is used as Embankment Filler, soil content is not higher than 40%, and red mud content is not higher than 50%.