State Key Laboratory of Coal Resources and Safe Mining, School of Mines, Nanhu Campus, China University of Mining & Technology, No. 1 University Road, Xuzhou, 221116, Jiangsu, China.
Environ Sci Pollut Res Int. 2020 May;27(14):16707-16717. doi: 10.1007/s11356-019-06932-y. Epub 2020 Mar 4.
As solid wastes are generated during coal mining, waste rocks can be backfilled into goaf so as to reduce geological hazards and environmental damage caused by coal mining; however, under different stress regimes, the sensitivities of factors influencing compression-induced deformation (CID) of waste rocks for backfilling (WRBs) are different. In order to control the compression-induced deformation of waste rocks for backfilling more efficiently, compression characteristics of waste rocks for backfilling under four different stress levels were tested by using a homemade loading test system for granular materials based on an orthogonal experiment. The influences of lithology, particle size distribution (PSD), lateral stress, and number of lateral loading cycles on compression-induced deformation of waste rocks for backfilling and sensitivities ranks of the four factors were analysed. The test results showed that: (1) under an axial stress of less than 10 MPa, lateral stress was considered the main factor influencing compression-induced deformation of waste rocks for backfilling; when the axial stress ranged from 10 to 20 MPa, particle size distribution was the main influencing factor; (2) under four different axial stress levels, the optimal combination of influencing factors is sandstone, a particle size distribution from 0 to 10 mm, 3 MPa lateral stress, and 7 lateral loading cycles; (3) to control the compression-induced deformation of waste rocks for backfilling, it was necessary to optimise the lateral stress under an axial stress of less than 10 MPa; while the axial stress was between 10 and 20 MPa, it was essential to optimise the particle size distribution.
由于在采煤过程中会产生固体废物，因此可以将废石回填到采空区，以减少采煤引起的地质灾害和环境破坏；然而，在不同的应力状态下，影响充填废石（WRB）压缩变形的因素的敏感性是不同的。为了更有效地控制充填废石的压缩变形，采用基于颗粒材料的自制加载试验系统，通过正交试验对四种不同应力水平下的充填废石压缩特性进行了测试。分析了岩性、粒度分布（PSD）、侧向应力和侧向加载循环次数对充填废石压缩变形的影响以及四个因素的敏感性等级。试验结果表明：（1）在轴向应力小于 10 MPa 的情况下，侧向应力被认为是影响充填废石压缩变形的主要因素；当轴向应力在 10-20 MPa 范围内时，粒度分布是主要影响因素；（2）在四种不同的轴向应力水平下，影响因素的最优组合是砂岩、粒径分布为 0-10 mm、3 MPa 的侧向应力和 7 次侧向加载循环；（3）为了控制充填废石的压缩变形，有必要优化轴向应力小于 10 MPa 时的侧向应力；而当轴向应力在 10-20 MPa 之间时，优化粒径分布是至关重要的。
