连续级配废石胶结充填体强度及变形特性试验研究

Experimental study of strength and deformation characteristics of cemented waste rock backfills with continuous gradation

采用MTS815岩石力学试验系统与自制的胶结充填体制作装置,对骨架颗粒满足Talbol级配理论的废石胶结充填体进行单轴抗压试验研究,分析了Talbol幂指数、初始孔隙度、胶结材料种类及含量对充填体强度及变形特性的影响规律。结果表明:充填体单轴抗压强度、弹性模量、变形模量均随Talbol指数n呈先增大、后减小的趋势;采用2次多项式拟合充填体单轴抗压强度与骨架颗粒Talbol指数的关系,得到了使充填体强度及变形特性达到最优的Talbol指数n=0.45。充填体单轴抗压强度基本上随其初始孔隙度的增大而减小,但当孔隙分布均匀性较差时,其试验结果具有一定差异。满足Talbol分布的充填体强度随其胶结材料胶结性能的提高而逐渐增大,其中水泥胶结充填体单轴抗压强度可以达到黏土胶结充填体的6倍以上。另外,胶结材料含量的提高同样可以增大充填体的强度,并能够相应地缩短其应力-应变曲线中的孔隙压密阶段。

Uniaxial compression experiment is carried out on the cemented waste rock backfill of which the framework particles satisfy Talbol grading theory by MTSS15 rock mechanics testing system and homemade device. The influences of Talbol index, initial porosity, type and content of cementitious material on the characteristics of strength and deformation of backfills are analyzed. The results show that the uniaxial compression strength, elastic modulus and deformation modulus of backfill increase first and then decrease with the increase of Talbol index. By adopting the quadratic polynomial to get the relations between the uniaxial compression strength of backfill and the framework grain Talbol index, it is concluded that when the Talbol index n is 0.45, the optimization of the strength and deformation characteristics can be achieved. Uniaxial compressive strength of backfill generally declines as the initial porosity increases and also can be affected by the pore distribution. When the uniformity of pore distribution is poor, it will cause the experimental results some differences. The strength of backfill, which meets the Talbol distribution, will increase as the glued performance of cementitious material improves. Among those materials, the uniaxial compression strength of backfill bonded with cement can be over 6 times higher than that of the specimen bonded with clay. In addition, the strength of backfill can be increased by the content of backfill enhanced. And in this way, the pore compaction stage in its stress-strain curve can be shortened.