Comprehensive assessment of clay soil stabilized by phosphate tailings: laboratory research, microscopic mechanism, and numerical simulation

The production of phosphate tailings (PT) is increasing, but utilization remains a challenge. In this study, PT was mixed with clay and stabilized with lime to prepare phosphate tailings stabilized soil (PTSS). Laboratory and microscopic tests were conducted to investigate the mechanical properties and mechanism of PTSS. Numerical simulation was used to analyze the deformation and dynamic response of PTSS.The optimal proportion was selected for field application. The results show that PTSS with 30% PT content has splendid mechanical properties, with unconfined compressive strength, California bearing ratio, and resilient modulus values of 0.55 MPa, 47.31%, and 71.49 MPa, respectively, well correlated among the three. The strength of PTSS is primarily influenced by particle gradation and the hydration reaction and pozzolanic reaction of lime with clay. The actual road performance was higher than the laboratory values.The sustainability indicators indicate that PTSS is an environmentally friendly and cost-effective subgrade material.