阅读说明：本技术 一种工作面双巷掘进小煤柱加固施工方法 (Working face double-lane tunneling small coal pillar reinforcement construction method ) 是由 黄万朋 王学文 张呈国 崔海峰 蒋力帅 郭晓胜 于 2020-04-09 设计创作，主要内容包括：本发明提供了一种工作面双巷掘进小煤柱加固施工方法,涉及煤矿开采及巷道支护技术领域。其步骤包括：在工作面布置双巷掘进,巷道之间留设3-5m的小煤柱；在小煤柱安装对穿锚索,使煤柱处于三向受力状态；小煤柱两侧设置注浆锚杆控制围岩裂隙,保证煤柱的完整性；安装悬吊锚索,加强煤柱与上覆岩层的联系,防止煤柱滑移；煤帮设置钢管混凝土墩柱加固,提高煤柱承载能力控制帮鼓；回采期间进行超前预断顶卸压,降低煤柱上方的支承压力。该方法保证了掘进和回采过程中小煤柱的稳定性,双巷掘进能够缓解矿井工作面接替紧张的问题,小煤柱的设置能够提高采出率；另外还提高了小煤柱的承载能力,保证了小煤柱的长期稳定,实现了留小煤柱的双巷掘进。(The invention provides a working face double-roadway tunneling small coal pillar reinforcement construction method, and relates to the technical field of coal mining and roadway support. The method comprises the following steps: arranging double-roadway tunneling on a working face, and reserving small coal pillars of 3-5m between the roadways; installing a through anchor cable on the small coal pillar to enable the coal pillar to be in a three-dimensional stress state; grouting anchor rods are arranged on two sides of the small coal pillar to control surrounding rock cracks, so that the integrity of the coal pillar is guaranteed; mounting a suspension anchor cable to strengthen the connection between the coal pillar and the overlying rock stratum and prevent the coal pillar from sliding; the coal side is provided with a steel pipe concrete pier column for reinforcement, so that the bearing capacity of the coal column is improved, and the side drum is controlled; and during the recovery period, advanced pre-top breaking pressure relief is carried out, and the supporting pressure above the coal pillar is reduced. The method ensures the stability of the small coal pillars in the tunneling and stoping processes, the problem of tension on the mine working face can be relieved by double-lane tunneling, and the mining rate can be improved by the arrangement of the small coal pillars; in addition, the bearing capacity of the small coal pillar is improved, the long-term stability of the small coal pillar is ensured, and the double-lane tunneling of the small coal pillar is realized.)

1. A working face double-lane tunneling small coal pillar reinforcement construction method is characterized by comprising the following steps:

step 1, performing double-lane tunneling on one side of a coal face, and reserving a small coal pillar of 3-5m between an advance lane and a delay lane;

step 2, supporting the roadway after the advance roadway and the lag roadway are tunneled, and driving a grouting anchor rod to the side of the small coal pillar in the roadway;

step 3, installing a suspension anchor cable, wherein the suspension anchor cable penetrates through the small coal pillar and is obliquely fixed in the overlying rock stratum;

step 4, installing opposite-penetrating anchor cables on the small coal pillars along with the lagging roadway driving working face, and applying lateral confining pressure to the two sides of the small coal pillars through the opposite-penetrating anchor cables;

step 5, arranging concrete-filled steel tube pier columns at the two sides of the small coal pillars 8-12m behind the driving working face of the lagging roadway, wherein the concrete-filled steel tube pier columns support the small coal pillars in an inclined manner towards one sides of the small coal pillars;

6, grouting two sides of the small coal pillar by using a grouting anchor rod 40-50m behind the driving working surface of the lagging roadway;

step 7, repeating the steps 1 to 6 until double-lane tunneling is completed;

and 8, after the coal face begins to recover, constructing the top breaking pressure relief in the advanced face of the coal pillar side in the roadway.

2. The working face double-roadway driving small coal pillar reinforcement construction method according to claim 1, wherein grouting anchor rods are arranged during roadway supporting after driving of the advancing roadway and the lagging roadway, and suspension anchor cables are installed at the same time.

3. The working face double-lane tunneling small coal pillar reinforcement construction method according to claim 1, wherein a connecting lane is arranged between every 50-100m of the tunnels, and the tunneling working face of one tunnel lags behind the tunneling working face of the other tunnel by 3-5m during double-lane tunneling.

4. The working face double-lane tunneling small coal pillar reinforcement construction method according to claim 1, wherein the length of the grouting anchor rod is less than half of the width of the small coal pillar, the anchoring end of the suspension anchor cable is arranged in the overlying hard rock stratum, and the vertical inclination angle of the suspension anchor cable is less than 30 degrees.

5. The working face double-lane tunneling small coal pillar reinforcement construction method according to claim 1, wherein during installation of the opposite anchor cables, construction is simultaneously performed on two sides of the coal pillar; and (3) pre-tightening the penetrating anchor cable by adopting a multi-cycle pre-tightening mode, and tensioning the penetrating anchor cable by adopting graded tensioning.

6. The working face double-lane tunneling small coal pillar reinforcement construction method as claimed in claim 5, wherein the total length of the through anchor cable is greater than the width of the small coal pillar, the through anchor cable comprises a free section and an exposed section, and the length of the exposed section is 200-300 mm.

7. The working face double-lane tunneling small coal pillar reinforcement construction method according to claim 1, wherein the concrete-filled steel tube pier column is inclined 3-5 degrees to one side of the small coal pillar, and a gap of 300-500mm is formed between the concrete-filled steel tube pier column and the small coal pillar.

8. The working face double-lane tunneling small coal pillar reinforcement construction method according to claim 7, wherein during construction of the steel tube concrete pier, 6-8 hollow steel tubes are erected, and then concrete is injected into the hollow steel tubes; and a steel tray is arranged at the top of the steel pipe concrete pier, and a flexible cushion layer is arranged between the steel tray and the hollow steel pipe.

9. The working face double-roadway driving small coal pillar reinforcement construction method according to claim 1, wherein the coal face begins to recover, top breaking drilling is conducted in advance of working face construction from a cut hole, holes are sealed after explosives are placed in the drilling holes, and pre-splitting blasting is conducted; and a sealing wall is arranged along with the propulsion of the working face to seal the connection roadway.

Technical Field

The invention relates to the technical field of coal mining and roadway support, in particular to a working face double-roadway tunneling small coal pillar reinforcement construction method.

Background

The traditional double-lane tunneling can realize the sequential stoping of a working face and ensure the normal mining and replacement; however, on the basis of mine pressure control, 10-30 m of protective coal pillars are generally reserved, which causes a great waste of coal resources. Although the width of a coal pillar is reduced, the resource extraction rate is improved, the roadway is close to a goaf and is easily subjected to large deformation caused by the influence of movement of a rock stratum above the goaf, so that the roadway is generally kept in a lag period of 6-10 months, and the problem of insufficient mining and replacement is brought. The current support control technology aiming at the small coal pillar mainly comprises the traditional anchor rod cable and metal net support, and the key parts are reinforced support, grouting, guniting and the like. Under the supporting system, supporting structures on two sides of the coal pillar are not connected, and bidirectional reinforcement cannot be guaranteed; meanwhile, the integrity of the coal pillar is damaged by excessive anchor rod cable holes on two sides, the small coal pillar is easy to generate plastic damage on the whole width, the bulging phenomenon is serious, the roadway can generate large deformation, and serious problems such as air leakage and fire disaster of a goaf can be caused. The combination of the existing support modes such as anchor rod, anchor cable and grouting is difficult to realize the long-term control of the small coal pillar, and the contradiction between the working face continuation and the coal extraction rate cannot be solved, so that the existing construction method needs to be further improved.

Disclosure of Invention

The invention provides a working face double-lane tunneling small coal pillar reinforcement construction method, which aims to solve the problem that stability control of small coal pillars reserved in double-lane tunneling is difficult due to the influence of mining, guarantee working face mining replacement, improve the coal mining rate and improve the bearing capacity of the small coal pillars.

A working face double-lane tunneling small coal pillar reinforcement construction method comprises the following steps:

step 1, performing double-lane tunneling on one side of a coal face, and reserving a small coal pillar of 3-5m between an advance lane and a delay lane;

step 2, supporting the roadway after the advance roadway and the lag roadway are tunneled, and driving a grouting anchor rod to the side of the small coal pillar in the roadway;

step 3, installing a suspension anchor cable, wherein the suspension anchor cable penetrates through the small coal pillar and is obliquely fixed in the overlying rock stratum;

step 4, installing opposite-penetrating anchor cables on the small coal pillars along with the lagging roadway driving working face, and applying lateral confining pressure to the two sides of the small coal pillars through the opposite-penetrating anchor cables;

step 5, arranging concrete-filled steel tube pier columns at the two sides of the small coal pillars 8-12m behind the driving working face of the lagging roadway, wherein the concrete-filled steel tube pier columns support the small coal pillars in an inclined manner towards one sides of the small coal pillars;

6, grouting two sides of the small coal pillar by using a grouting anchor rod 40-50m behind the driving working surface of the lagging roadway;

step 7, repeating the steps 1 to 6 until double-lane tunneling is completed;

and 8, after the coal face begins to recover, constructing the top breaking pressure relief in the advanced face of the coal pillar side in the roadway.

Preferably, when the roadway is supported after the advance roadway and the delay roadway are tunneled, a grouting anchor rod is arranged, and a suspension anchor cable is installed.

Preferably, one connecting roadway is arranged between the roadways every 50-100m, and the tunneling working face of one roadway lags behind the tunneling working face of the other roadway by 3-5m during double-roadway tunneling.

Preferably, the length of the grouting anchor rod is less than half of the width of the small coal pillar, the anchoring end of the suspension anchor cable is arranged in the upper hard rock stratum, and the vertical inclination angle of the suspension anchor cable is less than 30 degrees.

Preferably, when the anchor cable is installed, construction is simultaneously carried out on two sides of the coal pillar; and (3) pre-tightening the penetrating anchor cable by adopting a multi-cycle pre-tightening mode, and tensioning the penetrating anchor cable by adopting graded tensioning.

It is further preferred that the total length of the opposite-penetrating anchor rope is larger than the width of the small coal pillar, the opposite-penetrating anchor rope comprises a free section and an exposed section, and the length of the exposed section is 200mm and 300 mm.

Further preferably, the steel pipe concrete pier column is inclined to one side of the small coal column by 3-5 degrees, and a gap of 300-500mm is formed between the steel pipe concrete pier column and the small coal column.

Preferably, when the steel pipe concrete pier stud is constructed, 6-8 hollow steel pipes are erected firstly, and then concrete is injected into the hollow steel pipes; and a steel tray is arranged at the top of the steel pipe concrete pier, and a flexible cushion layer is arranged between the steel tray and the hollow steel pipe.

Preferably, the coal face is stoped, top breaking drilling is started from opening the cutting hole in advance of the face construction, and the hole is sealed after explosive is placed in the drilling hole, and presplitting blasting is carried out; and a sealing wall is arranged along with the propulsion of the working face to seal the connection roadway.

The working face double-lane tunneling small coal pillar reinforcing construction method provided by the invention has the beneficial effects that:

(1) the method adopts a double-lane tunneling mode, so that sequential stoping of a working face is ensured, and meanwhile, a stoping tunnel is pre-dug for the next working face, so that mining succession is ensured; the small coal pillars are comprehensively supported by using the opposite-penetrating anchor cables, the grouting anchor rods, the suspension anchor cables and the steel pipe concrete pier pillars, so that the stability of the coal pillars is ensured; during stoping, pressure relief is carried out by utilizing advanced top breaking, so that long-term stability of the roadway is ensured.

(2) The width of the small coal pillar reserved between the two roadways is far smaller than that of the protective coal pillar reserved in the traditional double-roadway tunneling, so that the extraction rate is greatly improved, the fire disaster caused by excessive coal pillars in the goaf is avoided, and the danger of rock burst can be effectively avoided.

(3) The method uses the opposite-penetrating anchor cable on the coal pillar between two roadways, so that the construction of the opposite-penetrating anchor cable is more convenient, the opposite-penetrating anchor cable changes the stress state of the small coal pillar, the small coal pillar is stressed in three directions, and the self bearing capacity of the coal pillar is improved; the grouting anchor rod can effectively control the surrounding rock cracks and enhance the integrity and stability of the small coal pillar; the suspension anchor cable strengthens the mechanical relation between the coal pillar and the overlying rock stratum and prevents the small coal pillar from slipping; the small coal pillars are reinforced from the side faces of the steel pipe concrete pier pillars and provide support for overlying rocks in cooperation with the small coal pillars, so that the bearing capacity of the coal pillars is further improved; and in the recovery process, the pressure of the overlying strata is relieved through advanced pre-breaking of the roof, so that the stability of the small coal pillar during the recovery period of the working face is ensured. The combination of the penetrating anchor cable, the grouting anchor rod, the suspending anchor cable and the steel pipe concrete pier column acts on the reinforcement of the small coal pillar, and acts on each stage of roadway excavation in a synergistic manner, the stability of the roadway is guaranteed through advanced top breaking pressure relief during the stoping period, and the long-term stable control over the small coal pillar is realized.

Drawings

Fig. 1 is a schematic plan view of a double-lane excavation;

FIG. 2 is a construction schematic diagram of a double-lane tunneling small coal pillar;

FIG. 3 is a schematic cross-sectional structure of a small coal pillar;

FIG. 4 is a diagram of a leading top-break pressure relief drilling construction layout;

in the figure: 1-advanced roadway; 2-a lagging roadway; 3-small coal pillar; 4-connecting lane; 5, oppositely penetrating anchor cables; 6-grouting anchor rod; 7, suspending the anchor cable; 8-steel pipe concrete pier stud; 9-a flexible cushion layer; 10-a steel tray; 11-section haulage roadway; 12-a track lane of the lower section; 13-a pilot hole; 14-blast hole; 15-working surface.

Detailed Description

A specific embodiment of the working face double-roadway tunneling small coal pillar reinforcement construction method provided by the present invention will be described with reference to fig. 1 to 4.