Study On The Spatial-temporal Distribution Law Of Separated Strata In Mining Overburden And The Subsidence Model Based On The Theory Of Allometric Growth

With the development of coal mining industry, the damage of the surface subsidence due to mining is gradually serious. The development process of separated strata in mining overburdens plays an important role in mining subsidence as an inevitable phenomenon. Therefore, building the relational model between the separated strata in mining overburden and the surface subsidence, studying the spatial-temporal distribution law of separated strata and analyzing the allometric characteristics of growth and development of separated strata in mining overburden, which can be able to further understand and improve the theory of mining subsidence, to provide important theoretical guidance meaning and practical value in engineering.This dissertation studies the spatial-temporal distribution law of separated strata and its relationship with the mining subsidence combined with the theory of allometric growth, which uses the methods of similar material simulation experiments and RFPA numerical simulation and regards the mining overburden separated strata in sedimentary strata as analysis objects. The main results are as follows:(1) In the process of coal seam mining, the growth states of separated strata is affected by the sedimentation rate difference in the upper and lower strata. When the subsidence velocity of the upper strata is less than the subsidence velocity of the lower strata, the separated strata is in the crack and development stage. Otherwise, the separated strata is in the closing stage, and is compacted gradually.(2) Mined-out area is formed after coal mining, the mining space shift upward in the strata, spreading to the surface and causing the surface subsidence eventually, which exists in the strata as the form of separated strata space. The growth states of separated strata will cause a certain influence on surface subsidence, a large number of separated strata come into the closing stages after stopping mining of coal seam, and then the surface subsidence is also gradually stabilized.(3) The growth rate of separated strata in mining overburden is diverse from each other in each stage, which reflects the allometric characteristics. The separated strata enter the development stage after the crack, which is in a state of positive allometric at that time, the length and width increased gradually until the maximum, since then, the separated strata comes into a state of negative allometric, whose length no longer change, width decreases, the separated strata begins to close.(4) Based on the theory of allometric growth, this dissertation studies the growth states of separated strata width in the process of mining, which obtains the relationship between separated strata in mining overburden and surface subsidence, and establishes the subsidence model based on allometric growth of separated strata in mining overburden according to the equivalent conversion process of each space in the strata.