CN103244122A - Trinity coupling support stability control method for gob-side entry-driving coal pillar - Google Patents

Abstract

The invention provides a trinity coupling support stability control method for a gob-side entry-driving coal pillar, which is particularly suitable for a large-deformation gob-side roadway with an unstable overlying rock. A pre-stress threaded steel anchor rod is used on the gob-side entry-driving coal pillar on an upper zone roadway coal pillar side to tension a coal pillar goaf-side coal body; a short anchor rod on a lower zone gob-side entry-driving coal pillar side is used for controlling the integrity of a whole displacement region of a coal pillar roadway side; and meanwhile, a long grouting anchor cable is matched to reinforce an anchoring point so as to limit the development of an inner separation layer in the whole displacement region. A range of generating a crushed region of the coal pillar under the effect of lateral supporting pressure can be relieved under the expression of a haling effect of the pre-stress threaded steel anchor rod, so as to prevent an instability state of the coal pillar from worsening; and 'controlling by the short rod and grouting by the long rod' of the short anchor rod and the long grouting anchor cable are given into fully play so as to prevent a coal pillar support structure from losing effect and re-achieve the supporting capability of a remained anchoring structure in the coal pillar, so that coupling support with alternative anchor net support and anchor grouting support is formed between the gob-side entry-driving coal pillar side and a goaf side.

Description

Three-in-one coupled support control method for coal pillar stability in gob-side driving

technical field

The invention relates to a coal pillar stability control method, in particular to a three-in-one coupling support control method for coal pillar stability in gob-side entry roadway with large deformation under unstable overlying strata in coal mines.

Background technique

The basis for the rapid development of gob entry technology is the surrounding rock control technology of gob entry, and maintaining the stability of narrow coal pillars is the key to the control of surrounding rock in gob entry. At present, the stability of narrow coal pillars in gob entry The research on control technology mostly focuses on the width of coal pillars before excavation and the support technology of coal pillars after excavation, etc., and the influence of roadway support in the upper section, excavation along gob-side roadway and mining in this working face has not been fully considered. During the process, the roadway surrounding rock control measures are considered uniformly, and the coal pillar stability technology of the gob-side roadway is comprehensively determined. Moreover, this kind of research is based on a basic condition, that is, the excavation along the goaf is carried out after the overburden of the goaf in the upper section is stable or basically stable. In contrast, due to the limitation of field test conditions However, there are still few studies on the surrounding rock control technology of gob-side entry under unstable overlying rock. In particular, in recent years, in order to alleviate the tense situation of production replacement in some coal mines, when the overlying strata in the goaf of the upper section of the working face have not been sufficiently stable, that is, by leaving narrow coal pillars along the goaf to carry out the work of the lower section of the working face. Excavation of mining roadways. This situation is called gob entry under unstable overlying rock. Under the condition that the overburden of the goaf in the upper section is not sufficiently stable, a stable residual bearing pressure has not been formed in the lateral coal body of the goaf, and the mine pressure is still unstable. The roadway generally has obvious deformation during the excavation period. When the working face is mined, affected by the advanced bearing pressure, the deformation and damage of the roadway are more serious, and even the expansion of the side is required to meet the production requirements, which will increase the production cost at the slightest and bring safety at the worst. Hidden danger. Gob-side entry, especially the stability control of gob-side entry under unstable overburden rock, is the key to the surrounding rock control of gob-side entry under this condition, and new technical solutions under the guidance of new ideas are needed to achieve the goal.

Contents of the invention

Technical problem: The purpose of the present invention is to solve the problems in the existing technology, and to provide a three-in-one coupling for effectively controlling the deformation of the surrounding rock of gob-side roadway and the stability of narrow coal pillars, and ensuring the safety of underground production. Support control method, this method is mainly aimed at driving along the goaf.

Technical solution: The three-in-one coupling support control method for coal pillar stability along gob-side roadway of the present invention includes the above steps:

a. During the excavation and support construction of the mining roadway in the upper section, when the overlying strata in the gob area of the working face in the upper section is not sufficiently stable, install multiple prestressing rods on the coal pillar side of the mining roadway in the upper section Threaded steel bolts, using the anchoring effect of prestressed threaded steel bolts to tighten the coal body at the side of the coal pillar roadway;

b. In the process of gob-side entry in the lower section, gob-side entry of the working face of the lower section is carried out, and a prestressed short anchor rod is installed on the side of the coal pillar of the gob-side entryway in the lower section, and the lengthened anchoring method is adopted;

c. During the process of gob-side roadway in the lower section of the working face, while installing the prestressed short bolt on the side of the gob-side roadway coal pillar, install the grouting anchor cable on the side of the gob-side roadway coal pillar in the lower section. The grouting anchor cable performs grouting on the coal pillar, and the anchor point of the grouting anchor cable goes deep into the unmoving area of the coal pillar, and the coal mass on the side of the coal pillar roadway, the coal mass displacement area on the side of the coal pillar mined-out area, and the coal pillar are not affected. The moving zone is reinforced.

Beneficial effects: the present invention uniformly considers the roadway surrounding rock control measures during the whole process from roadway support in the upper section to gob-side roadway excavation and working face mining influence, and determines a comprehensive gob-side roadway coal pillar stability control technical scheme, Through the three-in-one coupling support control of "strong pull, short control, and long injection", the details are as follows: (1) When the roadway is excavated in the upper section, high-strength prestressed threaded steel anchor rods are used on the coal pillar side to tighten the gob side of the coal pillar body of coal. The "strong pull" function of the high-strength prestressed rebar anchor rod on the side of the coal pillar in the upper section of the roadway can slow down the scope of the coal pillar's crushing area under the action of lateral support pressure, prevent the deterioration of the coal pillar's unstable state, and avoid the damage of the anchor bolt. Problems such as damage and breakage of the pallet and rod body provided the possibility for the anchor rod to play an anchoring role again after gob-side entry. (2) In the gob-side excavation of the lower section, short bolts are used on the coal pillar side of the roadway to control the integrity of the overall displacement area on the coal pillar roadway side. (3) When excavating gob-side roading in the lower section, long grouting anchor cables are used to reinforce the anchor points on the coal pillar side of the roadway to limit the development of abscission layers in the overall displacement zone. The full play of the "short control and long injection" effect of short anchor rods and long grouting anchor cables can effectively avoid the failure of the coal pillar support structure, and re-exert the support capacity of the left anchor structure in the coal pillar to achieve joint maintenance of the coal pillar stability effect. The invention can not only effectively avoid the failure of the coal pillar support structure, but also re-display the support ability of the anchorage structure left in the coal pillar during the roadway support in the upper section, and is useful for the stability maintenance of the coal pillar in the gob-side roadway and the roadway enclosure. Rock control has important guiding significance. This method has simple construction technology, economical support materials, remarkable support effect and wide practicability.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the present invention.

In the figure: 1—long grouting anchor cable, 2—prestressed short anchor rod, 3—working face in the lower section, 4—gobside roadway in the lower section, 5—coal body at the side of the coal pillar roadway, 6—coal pillar without Moving area, 7—coal pillar goaf side coal body, 8—prestressed rebar anchor rod, 9—upper section mining roadway, 10—upper section working face goaf.

Detailed ways

An embodiment of the present invention will be further described below in conjunction with accompanying drawing:

1) During the excavation and support construction of the mining roadway in the upper section, when the overlying strata in the goaf 10 of the working face in the upper section is not sufficiently stable, the coal pillar side of the large deformation along the gobside roadway is "strongly pulled" The three-in-one coupling support of "short control, long injection" is used to install the prestressed rebar anchor rod 8 on the side of the coal pillar of the mining roadway 9 in the upper section; the side of the coal pillar roadway is tightened by the anchoring effect of the prestressed rebar anchor rod 8 coal body 5;

2) In the process of goaf entry in the lower section, when the overburden stratum in the goaf 10 of the upper section working face is not sufficiently stable, the goaf entry of the lower section working face 3 can be carried out, and the prestressed short anchor The rod 2 is installed on the side of the coal pillar 4 in the goaf in the lower section, and the anchorage method is lengthened. The stability of the coal pillar is controlled by the fixed zone 6 of the goaf coal pillar, that is, the horizontal displacement change in the goaf coal pillar In extremely small areas, the integrity of the coal body needs to be guaranteed, and no large separation layers will be generated;

3) During the gob-side entry process of the working face 3 in the lower section, while installing the short prestressed anchor rod 2 on the coal pillar side of the gob-side entry, install the long grouting anchor cable 1 on the 4th coal pillar of the gobside entryway in the lower section On one side, use the long grouting anchor cable 1 to implement grouting on the coal pillar, and its anchorage point should go deep into the coal pillar immovable zone 6, so that the coal body 5 on the side of the coal pillar roadway and the coal body 7 on the side of the coal pillar goaf The displacement zone and the coal pillar fixed zone 6 are reinforced; through the combined use of the prestressed threaded steel anchor 8, the prestressed short anchor 2 and the long grouting anchor cable 1, the coal pillar side of the gob-side roadway in the lower section is connected to the Alternate coupling support of bolt-mesh support and anchor-grouting support is formed between the sides of the goaf, and the gob-side roadway in the lower section and the mining of the working face in the lower section are completed.

Claims (1)

1. a gob side entry driving coal column stability Trinity coupling supporting control method is characterized in that comprising the steps:

A, in upper curtate stope drift active workings drivings and supporting construction process, at upper curtate work plane goaf (10) overlying rock as yet under the fully unstable situation, in upper curtate stope drift active workings (9) coal column one side many prestressing force twisted steel anchor rods (8) are installed, are utilized prestressing force twisted steel anchor rod (8) anchorage effect tension coal column tunnel side coal body (5);

B, in lower curtate gob side entry driving process, carry out lower curtate work plane (3) gob side entry driving, at the short anchor pole (2) of lower curtate gob side entry (4) coal column one side prestressed, adopt to lengthen anchorage style;

C, in lower curtate work plane (3) gob side entry driving process, when the gob side entry driving coal column side short anchor pole of prestressing force (2) is installed, grouting cable anchor (1) is installed on lower curtate gob side entry (4) coal column one side, utilize grouting cable anchor (1) that coal column is implemented slip casting, the anchor point of grouting cable anchor (1) is deep in the motionless district of coal column (6), coal column tunnel side coal body (5), coal column goaf side coal body (7) displacement field and the motionless district of coal column (6) are reinforced.

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