CN103321677A - Method for actively controlling motion of coal mine critical layers by using strip filling walls - Google Patents

Abstract

The invention relates to a coal mine rock burst pre-controlling method, particularly to a method for actively controlling motion of coal mine critical layers by using strip filling walls. The method comprises the steps of calculating initial fracture steps of the coal mine critical layers by using a mine pressure theoretical model, determining intervals of the strip filling walls through combining experience safety factors, and calculating widths of the filling walls according to coal bed buried depths, rock stratum volume weights and unidirectional compressive strength of filling materials, and performing construction of the strip filling walls. According to the method, danger relieving measures passively adapted to abrupt fractures of critical layers in the prior art are changed into the measure of eliminating preconditions of fracture of coal mine critical layers in advance, so that pre-defense for coal mine rock burst is achieved. According to the method, the coal mining production efficiency can be improved, the work amount of filling construction of coal mine working faces is reduced, filling materials are saved, and the production cost per unit of coal is reduced.

Description

Utilize the method for strip filling body of wall ACTIVE CONTROL colliery key stratum movement

Technical field

The present invention relates to a kind of coal mine rock burst pre-control method, relate in particular to a kind of method of utilizing strip filling body of wall ACTIVE CONTROL colliery key stratum movement.

Background technology

Coal mine rock burst be in driving and the recovery process coal body that occurs or rock mass moment outstanding, cause casualties and tunnel, device damage even ground produce the disastrous dynamic phenomenon that shakes.

The control of coal mine rock burst still belongs to an international difficult problem, and damage tunnel thousands of rice because of bump every year, caused a lot of personnel casualty accidentses, and the billions of units of the direct economic loss of bringing have affected the safe working of nearly 10,000,000,000 tons of deepen coal resources.Therefore, the pre-control techniques of bump to capturing the international difficult problem of Controlling of Coal Outburst, has important scientific value.

The back production bump refers to because the bump that the propelling of stope is brought out.Wherein, to discharge be one of important reason of stope bump to the tight roof elasticity of flexure.In the stope progradation, the large tracts of land tight roof elasticity of flexure can discharge the bump that produces, and occurs in the moment of thick-layer tight roof brisement, and strong impact failure comprises following two parts:

1, by bring out coal seam, position, the bearing pressure peak elasticity of compression can the time discharge the destruction that causes work plane and winnning-off country rock;

2, the moment high speed settling of top board brisement, the destruction that the impact extruded rib causes.

Generally speaking, claim that the competent bed that this thickness is large, intensity is high is key stratum; Claim this bump to be " roof break type ".

The condition of key stratum fracture is: the extraction of coal body and the inbreak of the next rock stratum have changed the original mechanical equilibrium condition of key stratum and provide free space for the fracture of key stratum.

The danger releasing measures of bump mainly contains at present: loose coal release, water filling are softened; Large deformation energy-absorption bracket etc.The former principle is that forming plasticity unloads nip (buffer area) on every side adopting the space, can absorb the elastic energy of deep coal body sudden outburst after building up under the key stratum compression, and the protection roadway surrounding rock is not destroyed; The latter's principle is the quick deformability of utilizing support when deep coal body elastic energy abrupt release or key stratum rupture suddenly with the fast moving of certain rapid suitable for surrounding rock of supporting intensity and keeps the stable state of country rock.

These two kinds of methods all are that abrupt release or the key stratum that adapts to passively deep coal body elastic energy ruptures suddenly.

Summary of the invention

The objective of the invention is to propose a kind of strip filling body of wall ACTIVE CONTROL key stratum movement that utilizes, and then the technical scheme of the bump of key stratum fracture initiation appears in the prevention colliery.

The technical problem to be solved in the present invention is:

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of method of utilizing strip filling body of wall ACTIVE CONTROL key stratum movement may further comprise the steps:

1, its unidirectional tensile strength sigma is tested in the coring of drilling in key stratum _t

2, according to the mine pressure theoretical model, calculate the first secondary fissure section step pitch C of key stratum ₀

3, determine the spacing L of strip filling wall;

4, according to coal seam buried depth H, rock stratum unit weight γ, the unidirectional compressive strength σ of filler _cCalculate the width W of filling wall;

5, in coal mining construction working face progradation, every propelling L constructs a filling wall, until working face extraction finishes.

Technique effect of the present invention is, the filling wall that is positioned at coal mine gob has played supporting role to covering key stratum on it, make and cover key stratum on this and be in the mechanical balance state, do not possess the mechanical boundary condition that brisement occurs, thereby brisement can not occur, avoided the generation of the rock blast hazard that the unexpected brisement owing to key stratum causes.Simultaneously, because the filling wall has been born the weight of overlying rock, do not form the high stress concentrations district on the coal body around, avoided coal body the gathering of performance of being hit by a bullet, prevented the generation of the bump that caused by the release of the elastic energy of gathering in the coal body.

Strip filling body of wall of the present invention adopts the periodic stripes filling according to the brisement step pitch of key stratum, compare with existing bump danger releasing measures, the danger releasing measures of the unexpected fracture of the passive adaptation key stratum of prior art changed into the precondition of colliery key stratum fracture is eliminated in advance, fundamentally eliminated because the basic condition of bump is brought out in suddenly fracture of tight roof, must improve the level of security of work plane, thereby improve coal mining production efficiency;

For understanding better the present invention, the existing further common filling operation face of strip filling body of wall of the present invention and prior art being compared is analyzed as follows:

The common filling operation face of prior art comprises gob side entry retaining and two kinds of situations of goaf filling.

Gob side entry retaining filling operation face, need to build one the concrete filling wall by laying bricks or stones at the edge, goaf, width is generally 1.5-2.0m, height is consistent with head-room, strength grade of concrete is generally C20-C30, the length of its concrete wall is consistent with advance of the face length, is generally hundreds of rice or 1-2 km even longer distance.The purpose of gob side entry retaining is to utilize complete tunnel of the common formation of coal body of filling wall and back, base plate and an other side, as the gate road of next work plane.

The goaf filling work plane then is to utilize filler with whole goaf filling, and the sinking of control overlying rock plays a protective role to surface buildings.The used filler of goaf filling is generally C10 following concrete, high-water material or does not mix the ecosystem spoil etc. of cementitious material.

And strip filling body of wall of the present invention is periodically to build the concrete filling wall in the goaf by laying bricks or stones, length and face length are basically identical, and width then needs the filling wall spacing L and the concrete intensity σ that determine according to the weight of the overlying rock that is determined by the unit weight γ of buried depth H and rock, by the brisement step pitch of key stratum _cCalculate according to the mine pressure theoretical model, its concrete strength grade is generally C30, C40, C50 or higher, its filled wall build the fill volume that volume is far smaller than the goaf filling work plane by laying bricks or stones.

Therefore, its effect of strip filling body of wall of the present invention is obviously different from gob side entry retaining filling operation face and goaf filling work plane.Compare with common goaf filling work plane, need to carry out the space of filling and significantly reduce, the engineering quantity of construction operation significantly reduces, thereby can effectively save filler, reduction filling construction operation cost, enhances productivity.

More crucial is, strip filling body of wall of the present invention is compared with the common filling operation face of prior art, and the building construction method of the filled wall of the two is basic identical, is ripe prior art.But strip filling body of wall of the present invention is compared with the common filling operation face of prior art, and the purpose of the two, principle, structure, locality and distribution mode etc. are all not identical, and its stressing conditions is also fully different.

Description of drawings

Fig. 1 is filling operation face filled wall direction and the positional structure schematic diagram of prior art;

Fig. 2 is the goaf filling schematic diagram of prior art;

Fig. 3 is strip filling wall direction of the present invention and positional structure schematic diagram;

Fig. 4 is strip filling wall body structure schematic diagram of the present invention.

The specific embodiment

Contrast Fig. 1, with certain work plane coal seam buried depth 700m, coal seam thickness 3.0m, immediate roof is siltstone, thickness 9.3m, key stratum are middle sandstone, thickness 25m, unit weight 2.7t/m ³, the compressive strength of filled wall is that 40Mpa is that basic condition is illustrated implementation step of the present invention:

The coring of at first drilling is supposed to record that the unidirectional tensile strength values of sandstone is 10.49MPa in the key stratum;

1, calculate the first brisement step pitch of key stratum:

$C_0=\sqrt{\frac{2m{\mathrm{\σ}}_t\×100}{{\mathrm{\γ}}_z}}=\sqrt{\frac{2\×25\×10.49\×100}{2.7}}=139.37m$

2, determine the spacing L of strip filling wall: because the first brisement step pitch of key stratum is 139.37m, in conjunction with the safety factor empirical data, determine that the spacing of strip filling wall is: L=60m

3, calculate the width W of strip filling wall:

$W=\frac{H\×\mathrm{\γ}\×L}{{\mathrm{\σ}}_c\×100}=\frac{700\×2.5\×60}{40\×100}=26.25m.$

For the ease of construction, the width of filling wall is got 27m.

4, in the advance of the face process, every propelling 60m, constructing a width is 27m filling wall, until working face extraction finishes.

The spacing safety factor of selected strip filling wall is about 0.43 in the present embodiment, and this only is that the spacing safety factor empirical value span of actual strip filling wall can be 0.4-0.8 for giving an example that the round numbers convenience of calculation is carried out.

Claims (2)

1. method of utilizing strip filling body of wall ACTIVE CONTROL colliery key stratum movement is characterized in that may further comprise the steps:

Its unidirectional tensile strength sigma is tested and is obtained in the coring of drilling in key stratum _tStep;

According to the mine pressure theoretical model, calculate the first brisement step pitch C of key stratum ₀Step;

Determine the step of the spacing L of strip filling wall;

According to coal seam buried depth H, rock stratum unit weight γ, the unidirectional compressive strength σ of filler _c, the step of the width W of calculating filling wall;

In colliery mining construction working face progradation, every propelling length is that L constructs a filling wall, until the step that working face extraction finishes.

2. the method for utilizing strip filling body of wall ACTIVE CONTROL colliery key stratum movement according to claim 1 is characterized in that,

The first brisement step pitch design formulas of described key stratum is

Rice;

The spacing L of described strip filling wall is according to above-mentioned first brisement step pitch C ₀Evaluation multiply by the safety factor empirical value and determine, described safety factor empirical value is 0.4-0.8;

The width of described filling wall Rice.

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