地表塌陷区膏体回填控制颗粒流数值模拟

Numerical Simulation of Paste Backfill Control on Surface Subsidence by Particle Flow

以某矿地表塌陷区为工程背景,并基于颗粒流法和PFC2D程序,对塌陷区进行多种回填工艺模拟,得出在不同回填工艺下回填处置体的运移规律,可有效地对回填工艺进行优化与选择。研究结果表明:在塌陷坑底部矿石开采过程中,全部胶结回填方案中回填处置体沉陷位移量最小,沉陷情况控制效果最好,分层回填方案效果次之,全部非胶结回填方案效果最差;利用膏体回填地表塌陷区,可使处置体与周围岩体形成应力拱结构传递应力,对地表塌陷区的稳定性起到较好的控制作用;完全非胶结回填方案的离层因子最小,为0.12%,处置体颗粒与塌陷坑底部接触效果最好;完全胶结回填方案的离层因子最大,达到0.18%,接触效果最差;其余3种方案的离层因子值相近,分别为0.15%、0.16%、0.148%,接触效果位于前两者之间。

With the surface subsidence areas of a mine as engineering background, and based on particle flow method and PFC2D, numerical simulations on a variety of backfill schemes in surface subsidence areas are carried out. The migration rule of backfill disposal paste under different kinds of backfill schemes was obtained, which can optimize and select backfill technology effectively. The results are shown as follows ： in the process of mining under subsidence areas, the subsidence of backfill dispos- al paste in fully cemented backfitl scheme is minimum, which shows the best subsidence control effect. Stratified backfill scheme takes second and completely non-cemented backfill scheme is the worst;Using the paste backfill in surface subsidence can form stress arch in disposal paste and the surrounding rock mass which can pass stress and has a good control effect on the stability of the surface subsidence; Separation factor in completely non-cemented backfill scheme is minimum,0.12% ,which makes the best contact efficiency between disposal paste and bottom of the pit. The separation factor is maximum,0.18% in fully cemented backfill scheme, showing the worst contact efficiency. The rest schemes have similar separation factors ,0.15%, 0.16% and 0. 148% .and its contact efficiencv is located between the former two resnectivelv.