Flow Characteristics Of Paste Slurry In The Underground Stope And Control Technology Of Backfilling Roof-contact

The flow characteristics of the paste slurry in the underground stope are the key factors affecting the slurry surface curve and the sedimentation slope of the filling body.The control technology of backfilling roof-contact,based on this flow law,is an effective approach.This article focuses on the flow characteristics,and based on the rheology and non-Newtonian fluid mechanics to improve the roof-contact performance.The main research content:1.According to the requirements using waste rock and whole tailings as filling materials,the paddle rheometer and L-box are used to conduct rheological test.Meantime,boased on the similar between the L-box test principle and the slurry flow in the stope,the slump flow characteristics of paste slurry is explored preliminarily.2.For the paste slurry containing coarse aggregate,a CFD-DEM coupling simulation method is proposed to study the flow behavior.Based on the irregular characteristics of the rock particles,the non-spherical particle modeling method is used.The simulation result is in good agreement with the physical test.3.Summarized the physical test data and numerical simulation results of the L-box,a multi-parameter combination inversion analysis method based on SVM technology is proposed.The complete rheological parameters(yield stress,viscosity coefficient and power law index)of the paste slurry can be obtained from the test data of the L-box.This system provide new test methods for the research of paste rheological properties.4.Based on the inclined plate flow model of viscoplastic fluid,using(non-Newtonian)fluid mechanics research methods,and the paste slurry flow model is constructed.The theoretical model is analyzed and deduced by the lubrication theory,and the numerical solution of partial differential equations is used to solve the scheme.The flow mechanism,such as velocity field,yield surface,and "liquid surface" trajectory was obtained.5.Design a simulated stope test platform,investigate the influence of the rheological parameters,the position of the discharge port,the discharge flow rate,and the slope angle on the flow behavior of the paste.A model parameter correction scheme was proposed to make it more effective to predict the flow curve of the paste slurry.6.Research on control technology of backfilling roof-contact.Based on swelling filling materials technology,non-settlement or micro-swelling paste materials are formulated.With the help of the paste flow model,the discharging optimization and semi-industrial test are carried out.And then,suggestions are provided for better roof-contact performance.