铀尾砂胶结充填体三轴压缩试验及非线性强度准则研究

充填采矿法是矿山开采的重要施工方法，探究尾砂胶结充填体回填采空区后的强度特性具有重要的理论研究和工程实际意义。以铀尾砂胶结充填体为研究对象，研究砂灰比和围压对胶结充填体力学性能的影响。随后基于三种强度理论，以试验数据为基准，对不同砂灰比铀尾砂胶结充填体强度进行预测。结果表明：砂灰比对尾砂胶结充填体的力学特性有较大的影响；砂灰比为4,围压小于4 MPa时，铀尾砂胶结充填体的应力-应变曲线呈应变软化型，砂灰比大于4,铀尾砂胶结充填体的应力-应变曲线呈应变硬化型。黏聚力和内摩擦角随着砂灰比的增大而减小，逐渐趋于平稳，并呈指数下降趋势。Rocker准则公式简单，能精准地预测不同砂灰比条件下铀尾砂胶结充填体的强度。提出考虑砂灰比的铀尾砂胶结充填体的Rocker强度准则，并验证其具有良好的预测效果。研究成果为矿山充填开采提供了有益的参考。

Triaxial compression test and nonlinear strength criterion of uranium tailings cemented backfill

Backfill mining method is an important construction method of mining. It is of great theoretical research and engineering practical significance to explore the strength characteristics of cemented tailings backfill after backfilling goaf. The influence of sand-cement ratio and confining pressure on the mechanical properties of uranium tailings cemented backfill was studied. Then, based on the three strength theories and the experimental data, the strength of cemented uranium tailings backfill with different sand-cement ratios was predicted. The results show that the sand-cement ratio has great influence on the mechanical properties of cemented tailings backfill. (1) When the sand-cement ratio is 4 and the confining pressure is less than 4MPa, the stress-strain curve of uranium tailings cemented backfill shows strain softening type, and the sand-cement ratio is greater than 4. The stress-strain curve of uranium tailings cemented backfill shows strain hardening type (2) Cohesion and internal friction Angle decrease with the increase of sand-cement ratio and gradually tend to be stable. (3) Rocker criterion formula is simple, which can accurately predict the strength of uranium tailings cemented backfill under different sand-cement ratios. Rocker strength criterion of uranium tailings cemented backfill considering sand-cement ratio is proposed, and its good prediction effect is verified. The above research will provide a useful reference for filling mining.