Research Article

Research on Key Factors Influencing Surface Subsidence of Paste Backfilling Mining in Thick Coal Seam of Deep Mine

Table 2

Fuzzy membership degree of quantitative indicators.

NoQuantitative indexFuzzy membership degree

1Mining depthWhen the mining depth is greater than 800, the membership degree is 0, less than 200 is 1, and the middle is 0.5.
2Coal seamWhen the dip angle of the coal seam is greater than 54°, the membership degree is 0; when the dip angle of the coal seam is 0°, the membership degree is 1.
3Overburden structureWhen the uniaxial compressive strength (unit: MPa) ∈ (40, 80) (hard overburden), the membership degree is 0.3; when ∈ (20, 40) (medium hard overburden), the membership degree is 0.5; when ∈ (10, 20) (weak overburden), the membership degree is 0.7; when < 10 (very weak overburden), the membership degree is 0.9.
4Subsidence before fillingWhen the roof has no subsidence, the membership degree is taken as 1; when the roof is larger than 100 mm, it is taken as 0.
5Nonbackfilling accountWhen there is no subsidence, the membership degree is taken as 1; when it is greater than 60 mm, it is taken as 0
6Floating coalWhen there is no compression, the membership degree is 1; when the compression is greater than 50 mm, the membership degree is 0.
7Rock compressionWhen there is no compression, the membership degree is 1; when the compression is greater than 50 mm, the membership degree is 0.
8Volume shrinkageWhen there is no shrinkage, the membership degree is 1; when it is greater than 30 mm, it is 0.
9Volume compressionWhen there is no compression, the membership degree is 1; when the compression is greater than 50 mm, the membership degree is 0.
10Strength of filling bodyWhen the strength is greater than 5 MPa, the membership degree is 0; when the strength is less than 1 MPa, the membership degree is 1.
11Slicing heightWhen the slice mining height is greater than 5 m, the membership degree is 0; when the slice mining height is less than 1 m, the membership degree is 1.