Extra-thick coal seam gob-side coal roadway digging time design method based on a double-index weight method

Abstract

The invention relates to an extra-thick coal seam gob-side coal roadway digging time design method based on a double-index weight method. The method comprises the following steps: 1) determining gob-side roadway digging time T1 by taking basic roof subsidence as an index, 2) determining reasonable digging time T2 by taking roadway surrounding rock deformation rate as a time index; and 3) determining reasonable gob-side roadway digging time T. The basic roof subsidence and the overlying strata movement stabilization time are obtained on the basis of fully considering the difference of coal androck mass so that the field reality is better met and the result is more accurate; the roadway surrounding rock deformation rate is introduced as an additional index to form a double-index system of gob-side coal roadway digging time; 70% of the maximum basic roof subsidence value and the surrounding rock deformation rate (4mm / day) are proposed as evaluation indexes of the roadway digging time andthe weight ratio of the two is determined according to specific geological conditions, the gob-side roadway digging time is comprehensively obtained, the gob-side roadway surrounding rock safety andstability are guaranteed, the extra-thick coal seam gob-side roadway digging time is shortened and normal replacement of digging is guaranteed.

Description

technical field [0001] The invention relates to the field of coal mine roadway excavation and support, in particular to a method for designing the excavation time of a gob-side coal roadway in an extra-thick coal seam based on a double-index weighting method. Background technique [0002] Narrow coal pillar roading along the goaf refers to the preservation of coal pillars by leaving 3-5m narrow coal pillars at the edge of the goaf under the condition that the movement of the overlying strata in the adjacent goaf terminates and the stress redistribution caused by it tends to be stable. down the laneway. At present, gob-side entry with narrow coal pillars is mainly used in thin coal seams and medium-thick coal seams. Thin coal seams refer to coal seams with a single layer thickness less than 1.3m, and medium-thick coal seams refer to those with a single layer thickness greater than 1.3m and less than 3.5m. coal seam. In the process of mining thick and extra-thick coal seams,...

AI Technical Summary

Problems solved by technology

[0004] Through a large number of literature searches, it is found that there are no theoretical research and practical reports on the excavation time of gob-side roadways in ultra-thick coal seams above 15m

In the current engineering practice of extra-thick coal seams above 15m, there are two commonly used methods to determine the excavation time of gob-side roadway: one is to excavate the roadway after the movement of overburden rock is fully stabilized, that is, 12 to 16 months. The surrounding rock of the roadway is stable, and the maintenance of the roadway is good, but it seriously affects the succession of the normal production of the mine, resulting in difficulties in mine connection and a sharp drop in profitability

The second is to continue to use the traditional time of digging roadways from April to June, that is, to start digging roadways from April to June after the completion of mining at the adjacent working face. Severe deformation and instability of empty roadway

Images