1. A goaf filling method for reconstructing a broken roof structure in coal pillar-free mining is characterized by comprising the following steps:

step 1, gob-side entry retaining operation workers complete the vertical mold of a No. 1 filling body, pre-burying of a No. 1 goaf filling pipe, roadside filling, calculation of a filling design position, a filling space and a filling material consumption;

step 2, moving the waste rock blocking support along the mining direction of the working face, and completing the work of vertical mold setting of a No. 2 filling body, pre-embedding a No. 2 goaf filling pipe, roadside filling, filling design position, filling space and filling material consumption calculation by gob-side entry retaining workers;

step 3, continuously moving the waste rock blocking support along the mining direction of the working face, finishing the vertical mold of a No. 3 filling body, embedding a No. 3 goaf filling pipe, roadside filling, filling design positions, filling spaces and filling material consumption calculation work by gob-side entry retaining workers, simultaneously connecting a waste rock cemented filling pipeline to the No. 1 goaf filling pipe by the goaf waste rock cemented filling workers according to the calculation result of the filling space of the No. 1 filling pipe, starting pumping high-salinity water waste rock cemented materials, continuing pressurization when the design position of primary filling is reached, and stopping the filling work of the goaf when the design position of secondary filling is reached;

step 4, continuously moving the waste rock blocking support along the mining direction of the working face, and finishing the vertical mold, pre-embedding a goaf filling pipe, roadside filling, filling the design position, filling space and filling material consumption calculation work of the next filling body by gob-side entry retaining operation workers; meanwhile, a goaf gangue cemented filling operation worker connects a gangue cemented filling pipeline to a No. 2 goaf filling pipe, starts pumping high-salt water gangue cemented material, continues pressurizing when reaching a primary filling design position, and stops the goaf filling work when reaching a secondary filling design position;

step 5, drilling a long-distance hole from the position of the goaf filling pipe No. 1 by using a drilling machine to perform hole re-drilling, connecting the filling pipeline to the goaf filling pipe No. 1 again after the hole drilling construction is completed, starting pumping high-salt water fine slurry until the high-salt water fine slurry is completely filled into the goaf, stopping pumping, and cleaning the pipeline;

and 6, sequentially filling according to the advancing sequence of the steps 3-5 until the whole working face is completely stoped.

2. The goaf filling method for reconstructing a broken roof structure in coal pillar-free mining according to claim 1, wherein: the usage amount of the high-salt gangue cementing material required by the primary filling position in the step 3 is as follows:

V₁＝l×(m+h₁-k_ph₁)×L₃

in the formula: v₁Filling space below suspension before secondary breaking of key block B, m³；

l-the working surface advancing distance per day, m;

m is mining height, m;

k_p-direct jack crush expansion coefficient;

h₁-immediate roof thickness, m;

L₃the lateral overhang distance, m, before the secondary breakage of the key block B.

3. The goaf filling method for reconstructing a broken roof structure in coal pillar-free mining according to claim 1, wherein: the usage amount of the high-salt gangue cementing material required by the secondary filling design position in the step 3 is as follows:

in the formula: v₂Filling space after secondary breaking of new key block B and rotary sinking, m³；

l-the working surface advancing distance per day, m;

m is the working face mining height, m;

k_p-direct jack crush expansion coefficient;

h₁-immediate roof thickness, m;

L₂-substantially transverse to the lateral fracture span, m.

Background

At present, with the increase of mining strength of mineral resources, the mining of the mineral resources gradually develops towards refinement, sustainable type and greening direction, so that a tunnel mining arrangement form of non-pillar mining such as gob-side entry retaining, gob-side entry driving, 110 construction method and the like becomes a most reasonable mode for selecting a mine. In coal pillar-free mining, because a wall body (a narrow coal pillar or a roadside filling body) reserved for isolating a goaf is usually narrow, if the goaf cannot be sufficiently collapsed in time, a stress concentration effect is inevitably formed, and the isolating wall body is further endangered, so that the goaf is sufficiently collapsed or uniformly and slowly collapsed to the greatest extent. Just like the caving form of the top plate in the existing non-coal-pillar mining, namely the O-X breaking form, the key block B is inevitably rotated, sunk and intensively acted on the isolation wall, and the isolation wall is further endangered.

Aiming at the problems, the invention provides a goaf filling method for reconstructing a broken roof structure in coal pillar-free mining, aiming at achieving secondary breakage of a conventional O-X roof broken form in coal pillar-free mining through goaf filling, forming a new O-X broken form, ensuring that the goaf sinks slowly and consistently and reducing the degree of endangering an isolation wall body.

Disclosure of Invention

In order to solve the technical problem, the invention provides a goaf filling method for reconstructing a broken roof structure in coal pillar-free mining.

A goaf filling method for reconstructing a broken roof structure in coal pillar-free mining comprises the following steps:

step 1, gob-side entry retaining operation workers complete the vertical mold of a No. 1 filling body, pre-burying of a No. 1 goaf filling pipe, roadside filling, calculation of a filling design position, a filling space and a filling material consumption;

step 2, moving the waste rock blocking support along the mining direction of the working face, and completing the work of vertical mold setting of a No. 2 filling body, pre-embedding a No. 2 goaf filling pipe, roadside filling, filling design position, filling space and filling material consumption calculation by gob-side entry retaining workers;

step 3, continuously moving the waste rock blocking support along the mining direction of the working face, finishing the vertical mold of a No. 3 filling body, embedding a No. 3 goaf filling pipe, roadside filling, filling design positions, filling spaces and filling material consumption calculation work by gob-side entry retaining workers, simultaneously connecting a waste rock cemented filling pipeline to the No. 1 goaf filling pipe by the goaf waste rock cemented filling workers according to the calculation result of the filling space of the No. 1 filling pipe, starting pumping high-salinity water waste rock cemented materials, continuing pressurization when the design position of primary filling is reached, and stopping the filling work of the goaf when the design position of secondary filling is reached;

step 4, continuously moving the waste rock blocking support along the mining direction of the working face, and finishing the vertical mold, pre-embedding a goaf filling pipe, roadside filling, filling the design position, filling space and filling material consumption calculation work of the next filling body by gob-side entry retaining operation workers; meanwhile, a goaf gangue cemented filling operation worker connects a gangue cemented filling pipeline to a No. 2 goaf filling pipe, starts pumping high-salt water gangue cemented material, continues pressurizing when reaching a primary filling design position, and stops the goaf filling work when reaching a secondary filling design position;

step 5, drilling a long-distance hole from the position of the goaf filling pipe No. 1 by using a drilling machine, re-drilling the goaf charging pipe No. 1, connecting the filling pipeline to the goaf filling pipe No. 1 again after the drilling construction is finished, starting to pump the high-salt water fine slurry until the high-salt water fine slurry is completely filled into the goaf, stopping pumping, and cleaning the pipeline;

and 6, sequentially filling according to the advancing sequence of the steps 3-5 until the whole working face is completely stoped.

Further, the usage amount of the high-salt gangue cementing material required by the primary filling position in the step 3 is as follows:

V₁＝l×(m+h₁-k_ph₁)×L₃

in the formula: v₁Filling space below suspension before secondary breaking of key block B, m³；

l-the working surface advancing distance per day, m;

m is mining height, m;

k_p-direct jack crush expansion coefficient;

h₁-immediate roof thickness, m;

L₃the lateral overhang distance, m, before the secondary breakage of the key block B.

Further, the usage amount of the high-salt gangue cementing material required by the secondary filling design position in the step 3 is as follows:

in the formula: v₂Filling space after secondary breaking of new key block B and rotary sinking, m³；

l-the working surface advancing distance per day, m;

m is the working face mining height, m;

k_p-direct jack crush expansion coefficient;

h₁-immediate roof thickness, m;

L₂-substantially transverse to the lateral fracture span, m.

Has the advantages that: and (3) constructing a goaf isolation wall (namely a roadside filling body or a narrow coal pillar) in time after the working face is pushed, and providing a construction space and a grout stopping wall for goaf filling. And performing two times of high-salt gangue cemented filling and one time of high-salt fine slurry filling within the suspension range of the key block B of the gob, fully abutting the roof and providing a certain supporting resistance, ensuring that the key block B above the gob-side entry retaining is not broken, so that the arc-shaped triangular block at the end of the working face extends towards the inside of the gob to form a new basic roof O-X breaking form, ensuring that the gob sinks slowly and consistently, and reducing the degree of endangering an isolation wall.

Drawings

FIG. 1 is a schematic view of a gob filling process succession of the present invention

FIG. 2 is a plan view of the movement characteristics of a gob-side entry retaining top plate

FIG. 3 is a cross-sectional view of FIG. 2A-A

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

The invention principle comprises the following steps:

during the non-pillar mining, the direct roof is firstly collapsed along with the continuous forward propulsion of the working face, generally, the strength of the direct roof is relatively low, the direct roof is collapsed along with the mining, and the broken degree of the collapsed rock mass is good and the rock mass is scattered and accumulated. After the basic roof is broken for the first time, the structure formed by the rock stratum of the fractured zone always undergoes the changes of stabilization-destabilization-restabilization along with the continuous forward propulsion of the working surface, and the basic roof is broken periodically. The periodically broken rock blocks are basically propped to form a masonry beam structure along the direction of the working face, and two ends of the working face are broken to form arc-shaped triangular blocks 12, as shown in figure 2.

And constructing a goaf isolation wall 14 (namely a roadside filling body or a narrow coal pillar) in time after the working face is pushed, and providing a construction space and a grout stopping wall for goaf filling. And the backward goaf key block B16 is subjected to high-salt water gangue cemented filling within the suspension range, fully abuts against the roof and provides a certain supporting resistance, so that the key block B16 above the gob-side entry retaining is not broken, the arc-shaped triangular plate at the end of the working face extends towards the inside of the goaf, and a new basic roof O-X breaking form is formed, as shown in figures 2-3.

It should be noted that, in order to more accurately ensure that the pillar-free mining filling roof is broken again into the shape shown in fig. 2, the goaf filling space needs to be pre-calculated, and then the required filling material amount is obtained.

(1) Goaf filling space before secondary breakage of key block B

V₁＝l×(m+h₁-k_ph₁)×L₃ (1)

In the formula: v₁Fill space below suspension before secondary breaking of critical block B16, m³；

l-the working surface advancing distance per day, m;

m is mining height, m;

k_p-direct jack crush expansion coefficient;

h₁-immediate roof thickness, m;

L₃critical block B16 secondary break front lateral overhang distance, m.

(2) Secondary breaking new key block B17 rotary sinking back filling space

Constructing a high-water material roadside filling body and a goaf key block B suspension space to carry out high-salt water gangue cemented filling in time, and after having certain supporting resistance, ensuring that the end basic top key block B16 is not broken secondarily in the primary filling process, and the arc-shaped triangular plate moves towards the goaf. And after the new arc-shaped triangular plate 13 is broken in the goaf, the waste rock is contacted in a rotating mode to form a new triangular filling space. At the moment, the plane where the new arc-shaped triangular block directly pushes up the crushed and expanded gangue with the goaf after the gangue is contacted and the space formed by the once-filled wall of the goaf are triangular (shown in figure 2), the space is simplified into a right-angled triangle, and the formed filling space is as follows:

in the formula, V₂Filling space after secondary breaking of new key block B and rotary sinking, m³；

l-the working surface advancing distance per day, m;

m is the working face mining height, m;

k_p-direct jack crush expansion coefficient;

h₁-immediate roof thickness, m;

L₂-substantially transverse to the lateral fracture span, m.

Filling is carried out according to the calculation results of the primary filling space and the secondary filling space, and further the O-X breaking form of the reconstructed top plate in the coal pillar-free mining is achieved.

A goaf filling method for reconstructing a broken roof structure in coal pillar-free mining comprises the following steps:

(1) the gob-side entry retaining operation 1 worker completes the work of vertical mold of No. 1 filling body 4, pre-embedding gob filling pipe I12, roadside filling, filling design position, filling space and filling material consumption calculation under the shield of a gangue blocking bracket 7 at the side of a gob-side entry retaining 8;

(2) moving the waste rock blocking support, and finishing the work of vertical mold of No. 2 filling body 5, pre-embedding gob filling pipe II2, roadside filling, filling design position, filling space and filling material amount calculation by workers in gob-side entry retaining operation 2 under the shield of the waste rock blocking support 7;

(3) moving the waste rock blocking support 7, and finishing the vertical mold of the No. 3 filling body 6, embedding a gob filling pipe III3, roadside filling, filling design positions, filling spaces and filling material consumption calculation work by workers in gob-side entry retaining operation 1 under the shield of the waste rock blocking support 7; meanwhile, workers in 1 shift of goaf gangue cementing filling operation connect a gangue cementing filling pipeline to a goaf filling pipe I, start pumping high-salt water gangue cementing material, perform primary gangue cementing filling 9 to reach a primary filling design position, continue pressurizing, perform secondary gangue cementing filling 10, and stop filling work of the goaf when reaching the secondary filling design position;

(4) moving the waste rock blocking support, and finishing the work of vertical mold erection of a next filling body, pre-embedding a gob filling pipe, roadside filling, filling design position and filling space and filling material consumption calculation by 2 workers along the gob entry retaining operation under the shield of the waste rock blocking support; meanwhile, workers in goaf gangue cementing and filling operation 2 shift connect the gangue cementing and filling pipeline to a filling pipe II2, start to pump high-salt water gangue cementing material, continue to pressurize when reaching the initial specific position, and stop the goaf filling operation when reaching the set position again; and then, drilling a long distance to the goaf from the position of the filling pipe I1 by a drilling machine, connecting the filling pipeline to the filling pipe I1 again after the drilling construction is completed, starting pumping the high-salt water fine slurry 11 until the high-salt water fine slurry is completely filled into the goaf, stopping pumping, and cleaning the pipeline.

And (4) repeating the steps (3) and (4) until the whole working face extraction is finished.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.