Method and device for determining development status of separation layer of coal mine

A method for determining a development status of a separation layer in a coal mine, comprising:

• obtaining surface subsidence variation data of the coal mine within a preset time interval by a rock movement monitoring station set on a ground surface of the coal mine or by at least one Unmanned Aerial Vehicle;
• obtaining rock stress variation data of a caving zone corresponding to the ground surface of the coal mine by a stress measurement device buried in the caving zone;
• obtaining water pressure variation data of the caving zone corresponding to the ground surface of the coal mine by a water pressure measurement device buried in the caving zone;
• determining a height decrease of the caving zone based on the rock stress variation data and the water pressure variation data, comprising:
• calculating a maximum development height of the caving zone:
• P
• =
• ∑
• i
• =
• 1
• n
• γ
• i
• ⁢
• s
• i
• H
• =
• ∑
• i
• =
• 1
• n
• -
• 1
• s
• i
• +
• P
• 0
• -
• P
• γ
• n
• wherein, P refers to an intensity of pressure of the caving zone, in Pa;
• γi refers to a unit weight of a ith layer of the caving zone, in N/m3;
• si refers to a thickness of the ith layer of the caving zone, in m;
• n refers to a total number of layers of the caving zone;
• P0 refers to a stable intensity of pressure that a bottom plate of the caving zone experiences within the preset time interval;
• γn refers to a unit weight of a nth layer of the collapsed rock mass;
• and H refers to the maximum development height of the caving zone;
• calculating a total stress of the caving zone based on the maximum development height:
• r
• 0
• =
• M
• H
• +
• M
• ×
• 100
• ⁢
• %
• σ
• i
• ⁢
• j
• =
• (
• 1
• -
• r
• 0
• )
• ⁢
• P
• 0
• +
• r
• 0
• ⁢
• p
• 0
• wherein, M refers to a mining height from the ground surface to a position of the stress measurement device or the water pressure measurement device;
• H refers to the maximum development height of the caving zone;
• r0 refers to an initial porosity of blocks within a cubic a range of a cube occupied by a goaf of the coal mine;
• P0 refers to the stable intensity of pressure that a bottom plate of the caving zone experiences within the preset time interval;
• p0 refers to a pore water pressure in the goaf when the maximum development height of the caving zone is reached;
• σij refers to the total stress of the caving zone;
• calculating the height decrease of the caving zone based on the total stress:
• Δ
• ⁢
• h
• =
• M
• -
• P
• i
• -
• σ
• i
• ⁢
• j
• σ
• i
• ⁢
• j
• -
• p
• i
• ⁢
• H
• wherein, Pi refers to the rock stress variation data;
• pi refers to the water pressure variation data;
• σij refers to the total stress of the caving zone;
• H refers to the maximum development height of the caving zone;
• M refers to a mining height where a stress measurement device or a water pressure measurement device locates;
• Δh refers to the height decrease of the caving zone;
• in response to determining a difference between the height decrease and the surface subsidence variation data is less than a preset threshold, determining the development status of the separation layer is an undeveloped status;
• and
• in response to determining the difference between the height decrease and the surface subsidence variation data is larger than the preset threshold, determining the development status of the separation layer is a developed status;
• determining a development degree of the separation layer according to the difference between the height decrease and the surface subsidence variation data;
• and in response to determining the development degree reaches a preset early warning threshold, taking control measures for the caving zone to avoid occurrences of water damages.