State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China.
School of Resources and Safety Engineering, Chongqing University, Chongqing, 400044, China.
Environ Sci Pollut Res Int. 2021 Apr;28(14):17468-17481. doi: 10.1007/s11356-020-12148-2. Epub 2021 Jan 4.
Phosphogypsum (PG) is a solid waste product of the wet-process phosphoric acid industry that accumulates in large amounts on the ground, forming PG ponds. In recent years, the amount of PG produced and discharged into ponds has increased significantly with the increase in the market demand for phosphate fertilizers. To enrich the basic knowledge of PG properties and provide basic data for the stability analysis of PG dams, a series of laboratory geotechnical tests, including permeability tests, compressibility tests, triaxial shear tests, and dynamic triaxial tests, were conducted in this study. During the preparation of the test samples, solubility and high-temperature dehydration of PG were considered. The results indicated that PG exhibits medium compressibility and medium to weak permeability characteristics. The stress-strain curves of the triaxial shear tests were divided into three typical stages: initial deformation stage, strain hardening stage, and destruction stage. With increasing dry density and consolidation confining pressure, both the shear strength and deformation modulus significantly increased. The relationship between the deformation modulus and confining pressure gradually changed from linear to logarithmic with increasing density. The liquefaction resistance curves (CSR-N curves) of PG were expressed by power functions. With increasing dry density, the curves shifted higher and became steeper. Compared with the Hardin-Drnevich model, the Davidenkov model was found to be more suitable for describing the relationship between the dynamic shear modulus ratio and damping ratio of PG and the dynamic shear strain. Furthermore, compared with those of tailings and natural soils, the engineering mechanical properties of PG were relatively poor, which may be related to its uniform particle distribution and neat particle stacking structure.
磷石膏（PG）是湿法磷酸工业的固体废弃物，大量堆积在地面上，形成 PG 池。近年来，随着磷肥市场需求的增加，PG 的产量和排放量显著增加，堆积到 PG 池中的量也在增加。为了丰富 PG 性质的基础知识，并为 PG 坝的稳定性分析提供基础数据，本研究进行了一系列实验室土工试验，包括渗透试验、压缩试验、三轴剪切试验和动三轴剪切试验。在试验样品制备过程中，考虑了 PG 的溶解度和高温脱水。结果表明，PG 表现出中等压缩性和中等至弱渗透性特征。三轴剪切试验的应力-应变曲线分为三个典型阶段：初始变形阶段、应变硬化阶段和破坏阶段。随着干密度和固结围压的增加，剪切强度和变形模量均显著增加。变形模量与围压的关系随着密度的增加逐渐由线性变为对数。PG 的液化阻力曲线（CSR-N 曲线）由幂函数表示。随着干密度的增加，曲线向上移动且变得更陡峭。与 Hardin-Drnevich 模型相比，Davidenkov 模型更适合描述 PG 的动剪切模量比和阻尼比与动剪切应变之间的关系。此外，与尾矿和天然土相比，PG 的工程力学性能相对较差，这可能与其均匀的颗粒分布和整齐的颗粒堆积结构有关。
