采空区充填体强度分布规律试验研究

Experimental study on strength distribution of backfill in goaf

针对2种不同充填下料口位置,通过相似模型浆体充填试验,分析采空区充填浆体流动沉积规律及充填浆体颗粒质量分数分布规律,研究采空区充填体强度空间分布。根据采空区充填体强度分布特征,提出采空区充填体强度评价方法。研究结果表明:充填体强度受浆体颗粒质量分数影响,粗颗粒质量分数越大,其单轴抗压强度越大;充填浆体在流动沉积过程中,颗粒分布不均匀导致其充填体强度分布不均匀;在流动方向上,充填体强度分布基本符合正太分布规律,离充填口距离越大,粗颗粒质量分数越小,细颗粒质量分数越大,其充填体强度越小;在沉积方向上,充填体强度呈线性变化规律,随高度增加,粗颗粒质量分数降低,细颗粒质量分数增加,其强度线性降低;在采空区充填区域同时存在强度增强和损失区域,但只要该区域充填体强度大于规定的有效强度,即认为充填达到标准要求。

Aiming at the two different discharge outlets,the flow deposition law and the particle distribution of the slurry were analyzed,and the spatial distribution of the backfill strength was studied by the slurry filling similar model test.With the consideration of the characteristics of strength distribution in goaf,the strength evaluation method of backfill was put forward.The results show that the strength of backfill is affected by the content of the slurry particles.The larger the coarse particle content is,the larger the uniaxial compressive strength is,and the uneven distribution of the strength is caused by the uneven distribution of the particles.In flow direction,the distribution of the strength of backfill is basically consistent with normal distribution curve.The greater the distance from the discharge outlet is,the smaller the coarse particle content becomes,the larger the fine particle content becomes,and the smaller the strength of backfill increases.In deposition direction,the strength decreases linearly with the increase of the height.When the height increases,the coarse particle content become smaller and the fine particle content increases,and the strength decreases linearly.There is strength enhancement and loss area in the backfill area of goaf.As long as the strength of the backfill is larger than the specified effective strength,filling is thought to meet the standard requirements.