露天坑回填土石混合体的渗流特性及颗粒元数值分析

PERMEABILITY CHARACTERISTICS OF ROCK AND SOIL AGGREGATE OF BACKFILLING OPEN-PIT AND PARTICLE ELEMENT NUMERICAL ANALYSIS

针对土石混合体的渗透性,结合唐钢司家营铁矿III采场露天转井下的回填土石混合体工程,采用室内试验、现场试验和数值模拟的方法对其进行系统地研究,得出土石混合体的渗透系数与其非均匀度近似存在线性关系,渗透系数与混合土的孔隙比成正比;合理控制回填废石的粒径级配,降低平均粒径与非均匀度,可有效降低回填土石混合体的渗透性。通过颗粒元数值正交试验确定对土石混合体的渗流量影响顺序,并二次逐步回归出回填层厚度,水头压力,孔隙率,平均粒径对渗流量的关系式,为土石混合体防渗抗渗提供计算工具。

Combining with the backfilling（RSA） engineering in stope III of Sijiaying open-pit to underground iron mining of Hebei Iron and Steel Group Mining Co., Ltd., the permeability of rock and soil aggregate（RSA） is studied systematically by laboratory test, in-situ experiment and numerical simulation. The results show that there is an approximation linear relationship between the permeability coefficient of RSA and its non-uniform degree, and the permeability coefficient of RSA is directly proportional to the void ratio. The permeability of RSA can be reduced effectively by controlling the gradation of particle size of waste rock backfilled and reducing the average particle size and non-uniformity reasonably. The influence order to the seepage discharge of RSA is determined by particle element numerical orthogonal tests. The relationship formulas of the effects of four factors（thickness of back-packing, head pressure, porosity, particle diameter） on the seepage are obtained by quadratic stepwise regression analysis, and it can provide a calculation tool for impermeability of RSA.