Studies On Movement Rules Of Direct Roof And Compaction Strength Of Loess In Filling Mining With Loess

The paper first did a physical and mechanical experiment to the quasi-filling loess, and mainly studied its features of compression and creeping. On the basis of this, the author drew the variation curves, did the regression analysis, and the corresponding function was given. Then, the author built the structural model of solid filling mining, deduced calculation formula of first and periodic fracture length of direct roof based on this model and maximum deflection that direct roof reaches the first and periodic fracture length by using correlation formula of material mechanics. After analyzing and comparing these two deflections, we know that maximum deflection that direct roof reaches the first breakage length is always longer than that of direct roof reaches the periodic fracture length. So, this paper discussed these two deflections and reasonable equivalence mining height respectively and finally summarized the movement rules of direct roof in solid filling mining. On the basis of this, the compaction strength formula of loess filling in filling and mining was deduced by using Winkler’s theory of elastic foundation beam and stress-strain variation function in the loess compression experiment. In addition, the compaction strength formula of loess filling while filling and mining was deduced according to the variation function of compaction factor and stress, variation function of creep factor and stress in the loess compression creep experiment. The gap of loess compaction strength used in engineering practice deduced by these two ways is little, and there is of great significance to guide the engineering practice.It’s the first time to study movement rules of direct roof in solid filling mining and filling compaction strength of loess mass in loess filling mining, and deduced the relevant calculations. The work lays s strong foundation for further studying loess filling mining in future.