为了解决露天煤矿端帮充填开采过程中充填体无法接顶的问题和研究充实率对采硐变形破坏规律的影响，采用室内试验和数值模拟相结合的方法，分别研究了赤泥、水泥、矿粉的不同掺量对膨胀性充填材料不同性能的影响规律以及采硐在不同充实率条件下的变形破坏规律。研究表明：当赤泥、水泥、矿粉的质量比为4∶2∶3时，膨胀性充填材料的性能处于最优状态；顶板下沉极值和支撑煤柱压缩极值均与充实率呈二次函数降低关系；充实率处于80%~90%和90%~100%范围内，支撑煤柱压缩极值分别减小了约3.5 mm和6.5 mm，支撑煤柱减缓压缩速度随着充实率的提高呈现出增大趋势；不同充实率条件下，支撑煤柱的垂直应力变化规律均呈现出相互叠加的“马鞍形”分布特征；充实率在80%~100%区间内，上覆岩层塑性区发育高度随充实率提高而下降，整体下降速率随充实率的提高而增加；膨胀材料提高采硐充实率后，能显著减少顶板、支撑煤柱的变形量，缩小塑性区范围。

In order to solve the problem that the backfill body can not be connected to the roof in the process of end slope filling mining in open pit coal mine and to investigate the influence of filling rate on the deformation and failure characteristics of mining tunnel, the effects of different contents of red mud, cement and mineral powder on different properties of the expansive filling materials and the deformation and failure of the mining tunnel under different filling rates were studied by means of laboratory test and numerical simulation. The results indicate that when the mass ratio of red mud, cement, and mine powder is 4:2:3, the performance of the expansive filling material is optimal; the extreme values of roof subsidence and compression of supporting coal pillars exhibit a quadratic decreasing relationship with the filling rate; when the filling rate is in the range of 80%-90% and 90%-100%, the compression extremum of the supporting coal pillar decreases by about 3.5 mm and 6.5 mm, respectively, and the compression deceleration speed of the supporting coal pillar shows an increasing trend with the increase of the filling rate; under different filling rate conditions, the vertical stress variation of supporting coal pillars demonstrates a superimposed “saddle-shaped” distribution pattern; in the filling rate range of 80% to 100%, the development height of the plastic zone in the overlying strata decreases with the increase in filling rate, and the overall decrease rate of height accelerates with the rise in filling rate; increasing the filling rate with expansive materials significantly reduces the deformation of the roof and supporting coal pillars, narrows the plastic zone range.