常规三轴加载下尾砂胶结充填体的力学特性及能量变化特征

基于室内常规三轴压缩试验,结合能量耗散原理,系统研究了质量浓度及围压的变化对尾砂胶结充填体力学性能及能量演化特征的影响规律。结果表明：三轴加载下,尾砂胶结充填体的变形破坏均经历了微孔隙、裂隙压密阶段(OA)、线弹性变形阶段(AB)、屈服阶段(BC)及应变硬化阶段(CD)；充填体的峰值应力随着质量浓度或围压的增加而不断增大,其中一次函数能够很好的表达围压与峰值应力间的关系；充填体的残余应力及弹性模量随着围压的增大基本遵循一次函数和指数函数递增规律,且质量浓度的增加也有利于提高充填体的残余应力及弹性模量；充填体的裂纹分布密度均随着质量浓度或围压的增加而降低,说明围压或质量浓度的提高均能够有效的提高充填体的抗变形破坏能力；三轴加载下,充填体的总能量、弹性应变能及耗散能均随着围压或质量浓度的增加而增大,并且围压与各能量间的关系符合二次函数模型。

Mechanical properties and energy variation characteristics of tailings cemented backfill under conventional triaxial loading

Based on the indoor conventional triaxial compression test and the principle of energy dissipation, the effects of mass concentration and confining pressure on the mechanical properties and energy evolution characteristics of tailings cemented backfill are systematically studied. The results show that under triaxial loading, the deformation and failure of tailings cemented backfill experienced micro pore, fracture compaction stage (OA), linear elastic deformation stage (AB), yield stage (BC) and strain hardening stage (CD). The peak stress of backfill increases with the increase of mass concentration or confining pressure, and the first-order function can well express the relationship between confining pressure and peak stress. With the increase of confining pressure, the residual stress and elastic modulus of backfill basically follow the increasing law of primary function and exponential function, and the increase of mass concentration is also conducive to improve the residual stress and elastic modulus of backfill. The crack distribution density of the filling body decreases with the increase of mass concentration or confining pressure, indicating that the increase of confining pressure or mass concentration can effectively improve the deformation and failure resistance of the backfill. Under triaxial loading, the total energy, elastic strain energy and dissipation energy of the backfill increase with the increase of confining pressure or mass concentration, and the relationship between confining pressure and each energy conforms to the quadratic function model.