Experimental study on static and dynamic mechanical properties of phosphogypsum.

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