Roof Control Mechanism By Coordination With Backfilled Body And Backfill Support In Solid Backfill Mining Technology

Solid backfill mining as a typical representative method of green mining technology, its technology innovation and further foundation theory research is in line with significant demand of national energy strategy and an inevitable requirement of technology development itself. Focus on "roof control mechanism by coordination with backfilled body and backfill support" and basing on the lab test of backfill material, analysis of backfilled body’s site measurement, backfill support structural characteristics, engineering application, overburden movement characteristics of backfill mining, and supporting load characteristics of backfill support, By integrating use of field test, theoretical analysis, simulation analysis and numerical simulation method, this dissertation establishes the mine pressure mechanical model of overburden movement control by coordination with backfilled body and backfill support, gets the deflection equation of immediate roof under dense and non-dense backfill state, reveals the mechanism of roof control by coordination with backfilled body and backfill support under periodic weighting roof. Then, through building three dimensional entity model of backfill support, analysis its backfill properties, establishes evaluation and optimization method of design scheme based on this backfill properties. At last, set up an analytical model of backfilled body’s forming process by backfill support, analysis main influence factors on backfilled body’s density, reveals backfilled body’s forming mechanism, and proposes engineering control measures.The main innovative points are as follows:(1) This dissertation analyzes the stress-strain difference between compact and incompact backfilling materials. In addition, it also promotes a modified method to revise backfilling materials’ mechanical properties and obtained backfilling material’s modification curve of bulk density and elastic foundation coefficient.(2) The thesis builds theoretical mechanical model of cooperative control mechanism of roof with the cooperation of backfill body and backfilling hydraulic support. Besides, it simulates the operations of mining, support advancing and backfilling at backfilling workface by using the simulation software of ABAQUS and Pro/E. The simulation reveals the basic principles of roof control by coordination with backfilled body and backfill support. That is, backfill support controlling the subsidence of the roof within the supporting scope, transferring roof load and reducing the stress concentration; backfilled body bearing overburden load to inhibit roof movement, and the degree of inhibition is strictly controlled by its elastic foundation coefficient, the greater elastic foundation coefficient is, the greater pressure backfilled body bears, and the smaller the overburden displacement is.(3) The thesis studies the connotation of backfilling hydraulic support’s property and establishes evaluation system of backfilling support’s design scheme based on these properties. With this evaluation system, the designing and optimization method on backfill support’s structure is established, and research framework on backfill support is formed naturally, which includes initial scheme designing, scheme optimizing, evaluation index selecting, evaluating optimized scheme and backfilling properties controlling.(4) The dissertation reveals the forming mechanism of backfill body and builds an analytical model of compacted backfill body. Besides, the thesis analyzes main influence factors on backfilled body’s density, establishes expression formula between backfilled body’s density and initial density of backfilling material, length of backfilling web, tamping angle, and the tamping times and promotes the density control method of backfill body.