A double-index method for quantitatively judging the excavation time of gob-side roadway in extra-thick coal seam

Abstract

The invention relates to a double-index method for quantitatively judging the excavation time of a gob-side roadway in an extra-thick coal seam. 1 ; 2) Determine the reasonable excavation time T by taking the development depth of the roadway surrounding rock fissures as the time index 2 ; 3) Determine the reasonable excavation time T of gob-side roadway. On the basis of fully considering the differences of coal and rock masses, the basic roof subsidence and overlying rock movement stability time are obtained, which are more in line with the actual site and the results are more accurate. 2) The depth of fissure development in the surrounding rock of the roadway is introduced as an additional index to form a dual-index system for the excavation time of the gob-side coal roadway. 3) Take 70% of the maximum basic roof subsidence value and 80% of the maximum fissure depth as the evaluation index of roadway excavation time, and determine the weight ratio of the two according to the specific geological conditions, and comprehensively obtain the excavation time of the gob-side roadway to ensure The surrounding rock of the gob-side roadway is safe and stable, reducing the time for gob-side roadway digging in extra-thick coal seams, and ensuring the normal replacement of mining.

Description

technical field [0001] The invention relates to the field of coal mine roadway excavation and support, in particular to a double-index method for quantitatively judging the excavation time of a gob-side roadway in an extra-thick coal seam. Background technique [0002] Due to the advantages of high production, high efficiency, reduced roadway excavation, and ease of tension in the working face, gob-side roadway technology has been widely 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 , The medium-thick coal seam refers to the coal seam with a single layer thickness greater than 1.3m and less than 3.5m. In the process of mining thick and extra-thick coal seams, gob-side entry is rarely used, and the roadway protection method with 20-30m wide coal pillars is mostly used. Thick coal seams refer to those with a single layer thickness greater than 3.5m and less than 8.0m Coal seams, ultra-thic...

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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

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