磷石膏掺量对赤泥抗剪特性的影响

Effect of Phosphogypsum Content on Shear Properties of Red Mud

为扩大赤泥资源化、无害化利用途径,研究利用磷石膏改性赤泥应用于矿山充填和路基填筑等实际工程中的可能性。开展了赤泥、磷石膏以及磷石膏掺量分别为15%、30%、45%和60%的赤泥—磷石膏混合材料的直接剪切试验。试验发现:随着磷石膏掺量的增加,赤泥—磷石膏混合材料的剪应力—剪切位移关系曲线由软化逐渐趋于硬化,掺量为60%时变为应变硬化型;磷石膏能在一定程度上增强赤泥的抗剪强度,磷石膏掺量从15%增加到60%,试样的凝聚力逐渐减小,内摩擦角先增大后减小,掺量为15%时试样的凝聚力最大,掺量为30%时试样的内摩擦角最大。磷石膏掺入赤泥后,材料的力学性能得到了一定程度的改善,需开展更深入的研究,以将赤泥和磷石膏协同利用于实际工程中。

In order to expand the resource and harmless utilization of red mud,the possibility of us⁃ing phosphogypsum to modify red mud and applying it to mine filling and roadbed filling is studied.Direct shear tests of red mud,phosphogypsum,and red mud-phosphogypsum mixed materials have been carried out.The mixing amount of phosphogypsum in the mixed materials is 15%,30%,45%and 60%.The test found that with the increase of the phosphogypsum content,the shear stress-shear displacement relation⁃ship curve of the red mud-phosphogypsum mixed material gradually changes from softening to hardening,and becomes a strain hardening type when the content is 60%.Phosphogypsum can enhance the shear strength of red mud to a certain extent.When the content of phosphogypsum is increased from 15%to 60%,the cohesive force of the sample gradually decreases,and the internal friction angle increases first and then decreases.When the content is 15%,the cohesive force of the sample is the largest,and when the content is 30%,the internal friction angle of the sample is the largest.After phosphogypsum is mixed with red mud,the mechanical properties of the material have been improved to a certain extent,and more indepth research is needed to use red mud and phosphogypsum synergistically in practical engineering.