Gob-side entry retaining gangue blocking and support facilities and construction method for pillarless mining

Abstract

The present invention relates to a gob-side entry retaining gangue blocking and supporting facility and a construction method for pillarless mining. The gangue blocking and supporting facility is used for supporting the entry roadway and the lower outlet of the coal mining face; it includes fixed pillars supported between the roof of the working face and with the top inclined towards the entry roadway. The middle and upper parts of the fixed pillars are connected to the roof of the entry roadway through connecting rods. The connecting rods are supported from the middle and upper parts of the fixed pillars to the roof of the entry roadway; it is used to offset part of the pressure exerted by the gangue parallel to the coal mining face towards the entry roadway and part of the vertically downward pressure of the roof of the entry roadway. The construction method disclosed in the present invention is for constructing the above-mentioned gangue blocking and supporting facility. The present invention reduces the bearing pressure of anchor cables, fixed pillars, and the supporting facilities of the roof of the entry roadway. It provides better guarantee for gangue blocking of gob-side entry retaining and stable support of the roadway.

Description

Technical Field

[0001] The present invention relates to a new technology for safe coal mining, specifically to the gob-side entry retaining gangue blocking and support facilities without coal pillars and the construction method thereof. Background Art

[0002] Gob-side entry retaining without coal pillars means leaving the machine roadway of the previous mining area as the air roadway of the next mining area, and there is no coal pillar support during the entry retaining, and all mining operations are carried out. This method is an advanced underground mining technology for rationally developing coal resources, improving coal recovery rate, reducing roadway driving volume, and is beneficial to the safe production of the mine and improving the technical and economic benefits of the mine. It not only has practical significance for production mines to improve coal recovery rate, ease the tension between mining and excavation replacement, and extend the mine life, but also is one of the ways for coal enterprises to improve safety conditions and technical and economic indicators, increase production, increase profits and reduce losses. The gob-side entry retaining technology has more technical and economic advantages than driving roadways with coal pillars both in terms of using coal resources and in terms of coal mining methods.

[0003] However, after canceling the support coal pillar, due to the influence of mining vibration during mining and the accumulation of gob gangue on the upper side of the roadway after it rolls down, a pressure towards the roadway is formed. Therefore, how to better support the area between the gob and the machine roadway has become the guarantee for safe coal mining.

[0004] In the mining of steeply inclined coal seams, the gob gangue slides down along the bottom plate of the steeply inclined gob (towards the machine roadway). The support facilities set on the upper side of the roadway are used to block the sliding gangue, causing the gangue to accumulate on the upper side of the roadway. The accumulated gangue acts on the support facilities, and the support facilities will bear a large pressure. Especially for the fixed pillars mainly bearing the impact of gangue sliding between the gob roof and floor, which are fixed by the anchor cables at the top and bottom ends of the fixed pillars, the anchor cables also bear a large pressure. Moreover, one end of the anchor cable tail is subjected to a downward pulling force and the other end is subjected to a lateral shearing force. Therefore, the support structure of the existing support facilities is unevenly stressed, and some structures bear a large pressure, which is prone to cause problems such as gangue washing, deformation of the roof and floor of the machine roadway, and the upper and lower sides of the roadway. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a gob-side entry retaining gangue blocking and support facility without coal pillars and the construction method thereof.

[0006] Among them, the gob-side entry retaining gangue blocking and support facility without coal pillars of the present invention is set at the machine roadway of the steeply inclined coal seam and the lower exit of the coal mining face, and supports this place; the lower exit of the coal mining face has a working face bottom plate inclined at 35° - 55° to the horizontal plane and a working face roof parallel to the working face bottom plate; the upper side and the lower side of the machine roadway are vertically arranged, and the machine roadway roof and the working face roof are in the same plane. Among them, it includes:

[0007] A fixed support pillar that is set between the working face floor and the working face roof, with its top inclined towards the machine roadway.

[0008] A connecting rod is provided to connect the upper and middle parts of the fixed support pillar to the roof of the machine roadway. The connecting rod has a first end of the connecting rod at the connection with the fixed support pillar and a second end of the connecting rod at the connection with the roof of the machine roadway.

[0009] The connecting rod is supported from the upper and middle parts of the fixed support pillar towards the roof of the machine roadway; it is used to offset part of the pressure exerted on the gangue parallel to the coal mining face towards the machine roadway direction and part of the vertically downward pressure of the roof of the machine roadway.

[0010] For the gob-side entry retaining gangue blocking and support facilities in non-pillar mining as described above, between the floor of the machine roadway and the roof of the machine roadway, a hydraulic support pillar is detachably provided. Specifically, it is advanced and supported between the floor of the machine roadway and the roof of the machine roadway before the coal mining face advances, and is removed after the coal mining face advances;

[0011] It includes a hydraulic support pillar supported below the second end of the connecting rod, and a wooden cushion block is provided between the top end of the hydraulic support pillar and the connecting rod.

[0012] For the gob-side entry retaining gangue blocking and support facilities in non-pillar mining as described above, a first cable bolt is provided on the working face roof. The front end of the first cable bolt is driven into the working face roof, and the tail end passes downward through the fixed support pillar and is then anchored to the connecting rod below the fixed support pillar. Specifically, it is anchored to the first end of the connecting rod; the first cable bolt is vertically arranged;

[0013] A second cable bolt is provided on the roof of the machine roadway. The front end of the second cable bolt is driven into the roof of the machine roadway, and the tail end is anchored to the second end of the connecting rod.

[0014] For the gob-side entry retaining gangue blocking and support facilities in non-pillar mining as described above, a column cap is provided at the connection between the connecting rod and the roof of the machine roadway.

[0015] The column cap is a right-angled wedge protruding upward and is used to be embedded in the roof of the machine roadway.

[0016] Below the wedge is a right-angled wedge-shaped groove, and the end wedge formed by the perpendicular intersection of the upper surface and the end surface of the second end of the connecting rod is inserted into the wedge-shaped groove.

[0017] One of the surfaces forming the right-angled wedge has an anchor hole through which a second anchor bolt passes. The tail end of the second cable bolt passes through the anchor hole and is then anchored to the second end of the connecting rod.

[0018] The two sides of the right-angled wedge have brims for fitting the roof of the machine roadway.

[0019] For the gob-side entry retaining gangue blocking and support facilities in non-pillar mining as described above, a T-shaped steel strip is provided on the roof of the machine roadway and is arranged along the roof of the machine roadway starting from the second end of the connecting rod to the lower side of the roadway.

[0020] Anchor nets are installed on the roof of the roadway along the working face, on the upper side of the roadway, and on the lower side of the roadway, and are pressed against the rock wall by T-shaped steel straps.

[0021] For the gob-side entry retaining gangue and support facilities in non-pillar mining as described above, the fixed support is an I-beam, and a long hole for the cable bolt to pass through is provided on the web at two-thirds of the upper part of the fixed support.

[0022] The connecting rod is an I-beam, and anchor holes for the cable bolt to pass through are provided on the webs at the first end and the second end of the connecting rod.

[0023] The distance between the outer sides of the two flanges of the I-beam of the connecting rod is smaller than the distance between the inner sides of the two flanges of the I-beam of the fixed support, so that the connecting rod can be inserted into the two flanges of the fixed support.

[0024] For the gob-side entry retaining gangue and support facilities in non-pillar mining as described above, the connecting rod is horizontally arranged; the first end of the connecting rod is connected to two-thirds of the fixed support from bottom to top.

[0025] The top end of the fixed support inclines towards the roadway along the working face, so that an angle of 70° - 80° is formed between the fixed support and the working face floor;

[0026] Drive the third cable bolt into the upper side of the roadway along the working face in a direction perpendicular to the upper side of the roadway to support the upper side of the roadway along the working face.

[0027] The construction method of the present invention is used for constructing the gob-side entry retaining gangue and support facilities in non-pillar mining as described above, including construction in the advanced stage and construction in the lagging stage;

[0028] Among them, the construction in the advanced stage includes the following steps:

[0029] Before the coal mining face advances, construct a support notch on the working face floor and a cap notch on the roof of the roadway along the working face that is adapted to the cap.

[0030] Drive anchor holes into the upper side of the roadway along the working face and the cap notch on the roof of the roadway along the working face;

[0031] Install the second cable bolt, the third cable bolt, and the cap.

[0032] Insert the lower end of the fixed support into the support notch and connect the upper end to the roof; connect the middle and upper parts of the fixed support to the first end of the connecting rod, and pass the second cable bolt through the cap and tension and clamp it.

[0033] Support the hydraulic support under the second end of the connecting rod.

[0034] Among them, the construction in the lagging stage includes the following steps:

[0035] Remove the hydraulic support; tension and clamp the movable margin generated at the tail end of the second cable bolt.

[0036] After the goaf is cut-bottom pressure relief, the slack generated at the tail end of the second cable bolt is tensioned and clamped again.

[0037] The following steps are also included:

[0038] Before the coal mining face advances, drill anchor holes in the roof of the working face and install the first cable bolt.

[0039] After passing the first cable bolt through the upper middle part of the fixed support, connect it to the end of the connecting rod and perform tensioning and clamping.

[0040] Among them, the following steps are also included in the construction during the lag phase: tension and clamp the slack generated at the tail end of the first cable bolt, and then remove the hydraulic support.

[0041] The following steps are also included:

[0042] In front of the column cap, first install the anchor mesh, leave a blank for installing the column cap on the anchor mesh, pass the right-angled wedge of the column cap through the blank and insert it into the notch of the column cap, and the cap edge presses on the anchor mesh.

[0043] After the second cable bolt passes through the column cap, then pass through the second end of the connecting rod, pass through the T-shaped steel strip, and then perform tensioning and clamping on the end of the second cable bolt.

[0044] Beneficial technical effects:

[0045] The present invention utilizes the function of the connecting rod to transfer part of the pressure exerted by the gangue on the fixed support towards the roadway side to the roof of the roadway, offset it with part of the pressure on the roof of the roadway, and reduce the bearing pressure on the first cable bolt, the fixed support, and the supporting facilities on the roof of the roadway. It provides better guarantee for gangue blocking along the gob-side entry retaining and stable support of the roadway. Description of the Drawings

[0046] Figure 1 Schematic diagram of the force on the gangue blocking and supporting facilities of the present invention;

[0047] Figure 2 It is a schematic diagram of the structure of the gangue blocking and supporting facilities of the present invention, mainly showing the structure of the gangue blocking and supporting facilities in the advanced stage;

[0048] Figure 3 It is a schematic diagram of the structure of the gangue blocking and supporting facilities of the present invention, mainly showing the structure of the gangue blocking and supporting facilities in the lag stage;

[0049] Figure 4 It is a schematic diagram of the connection relationship between the second end of the connecting rod, the column cap, the anchor mesh, the T-shaped steel strip, and the hydraulic support.

[0050] Figure 5 It is a schematic diagram of the connection relationship between the first cable bolt, the fixed support, and the first end of the connecting rod.

[0051] Figure 6 It is a schematic diagram of a column cap structure.

[0052] Among them, the attached drawing reference numerals are: working face roof 1; working face floor 2; fixed support 3; hydraulic support 4; conveyor belt 5; machine roadway 6; connecting rod 7; gob 8; third cable bolt 9; upper side of machine roadway 10; lower side of machine roadway 11; floor of machine roadway 12; first cable bolt 13; second cable bolt 14; roof of machine roadway 15; column cap 16; wooden cushion block 17; T-shaped steel strip 18; anchor net 19; long strip hole 20; flange 21; web 22; brim 23; column cap notch 24. Specific implementation manners

[0053] The present invention is applied to a steeply inclined coal seam with an inclination angle of 35° to 55°.

[0054] In the following examples, the direction indication of each component is as follows: taking the direction where the gob 8 (or coal mining face) is located as "rear", and the direction of the machine roadway 6 as "front"; the coal mining face, gob, and machine roadway all have a roof and a floor, taking the direction where the roof is located as "upper", and the direction where the floor is located as "lower".

[0055] The gob-side entry retaining gangue and support facilities for non-pillar mining in this example are arranged between the upper side of the machine roadway in a steeply inclined coal seam and the lower outlet of the coal mining face, as well as in the machine roadway, and support is carried out at this place.

[0056] The coal seam to be mined and the gob after mining are inclined, with an inclination angle of 35° to 55°;

[0057] Among them, the lower outlet of the coal mining face has a working face floor 2 inclined at 35° to 55° with respect to the horizontal plane, and a working face roof 1 parallel to the working face floor; the roof 15 of the machine roadway and the working face roof 1 are in the same plane. The floor of the machine roadway is a horizontal plane; the upper side 10 and the lower side 11 of the machine roadway are vertically arranged. The lower section of the upper side of the machine roadway is rock mass, and the upper section is a coal seam (specifically, a support notch dug out in the coal seam, and fixed columns are arranged in the support notch).

[0058] The machine roadway 6 has a special-shaped cross-section, with a net width of 3300 mm, a height of the high side of 3500 mm, and a height of the low side of 1600 mm.

[0059] Facilities such as a conveyor belt 5, a pedestrian passage, a drainage ditch, and a cable rack are arranged in the machine roadway.

[0060] Among them, after the roof cutting and pressure relief of the gob, the gangue in the gob 8 slides down along a slope of 35° to 55° (parallel to the coal mining face) towards the machine roadway direction and is blocked by the fixed support, and the pressure is applied to the fixed support. A row of fixed supports is arranged on the upper side of the machine roadway, and there is a wooden board behind the fixed supports. The wooden board is arranged between each fixed support to prevent the gangue from sliding into the machine roadway.

[0061] Example 1:

[0062] The gob-side entry retaining gangue and support facilities for pillarless mining include conventional support facilities, such as the fixed pillar 3 set between the working face floor 2 and the working face roof 1, and the top end of which inclines towards the machine roadway. In particular, a connecting rod 7 connecting the upper middle part of the fixed pillar 3 and the machine roadway roof is provided, and the connecting rod supports from the upper middle part of the fixed pillar towards the machine roadway roof 15; Refer to Figure 1 The connecting rod 7 is used to offset part of the pressure 01 exerted by the gangue parallel to the coal mining face towards the machine roadway direction and part of the vertically downward pressure of the machine roadway roof.

[0063] Among them, the upper end of the fixed pillar 3 is fixed by the anchoring tension provided by the first cable bolt 13, while the machine roadway roof 1 is fixed by the roof support facilities (the advanced support relies on hydraulic props, cable bolts and anchor bolts; the lag support relies on cable bolts and anchor bolts); Therefore, the function of the connecting rod 7 reduces the pressure on the first cable bolt 13 and at the same time reduces the pressure on the support facilities of the machine roadway roof 15.

[0064] Refer to Figure 2 During the advanced support, a hydraulic prop 4 is provided between the machine roadway floor 12 and the machine roadway roof 15, specifically advanced supported between the machine roadway floor and the machine roadway roof before the coal mining face advances and removed after the coal mining face advances; In this example, at least two rows of hydraulic props 4 are required. One row is close to the upper side of the machine roadway 10, supported from the intersection of the upper side of the machine roadway 10 and the machine roadway floor 12 to the first end of the connecting rod at the machine roadway roof 15. The hydraulic prop inclines forward by 12° (forming a 12° angle with the vertical direction). A wooden cushion block 17 is provided between the top end of the hydraulic prop and the connecting rod 7. Utilizing the soft characteristics of the wooden cushion block, the top end of the hydraulic prop is adapted to the complex structural surface at the supported place.

[0065] In this example, the connecting rod 7 is made of I-beam. The I-beam has two parallel flange edges, and then a web is vertically arranged between the two flange edges. The connecting rod is basically horizontally arranged.

[0066] Taking the connection point of the connecting rod and the fixed pillar as the first end of the connecting rod, and the connection point of the connecting rod and the machine roadway roof as the second end of the connecting rod.

[0067] The machine roadway roof 15 is provided with a second cable bolt 14. The front end of the second cable bolt is driven into the machine roadway roof, and the tail end is anchored to the second end of the connecting rod.

[0068] In order to better support the machine roadway roof, usually a tray is set at the tail end of the cable bolt. In this example, the second cable bolt cancels the tray, or improves the tray, and replaces the tray with a column cap 16.

[0069] Refer to Figure 4 、 Figure 6, the cap 16 is arranged at the connection between the connecting rod 7 and the roadway roof 15. The cap 16 is a right-angled wedge protruding upwards and is used to be embedded in the cap notch of the roadway roof. Below the wedge is a right-angled wedge-shaped groove. The end wedge formed by the perpendicular intersection of the upper surface of the second end of the connecting rod with the end face is inserted into the wedge-shaped groove. One of the faces forming the right-angled wedge has an anchor hole through which the second bolt passes. The tail end of the second cable passes through the anchor hole and is anchored to the second end of the connecting rod. Both sides of the right-angled wedge have brims 23 for fitting the roadway roof.

[0070] Therefore, the cap 16 in this example can be subjected to forces in two directions, and both ultimately transfer to the roadway roof. One direction is the tensile force of the cable on the cap, and the other direction is the supporting force of the connecting rod perpendicular to the tensile force of the cable. Ultimately, the resultant force direction of the two-direction forces is perpendicular to the roadway roof direction to support the roadway roof. The cap 16 is made of a steel plate with a thickness of 10 mm.

[0071] The fixed props 3 are arranged along the roadway direction with a spacing of 500 mm using 11# I-beams, and are installed at a position 500 mm away from the upper side of the roadway on the coal mining face floor. Waste wooden boards, rubber sheets, and wire meshes are laid behind the fixed props for full-section closure.

[0072] In this example, both the fixed props and the connecting rods are made of I-beams. The I-beam consists of two flanges 21 and a web 22. The top of the fixed prop 3 inclines towards the roadway, forming an angle of 70° - 80° between the fixed prop and the working face floor.

[0073] The distance between the outer sides of the two flanges of the I-beam of the connecting rod is less than the distance between the inner sides of the two flanges of the I-beam of the fixed prop, so that the connecting rod can be inserted into the two flanges of the fixed prop.

[0074] The first end of the connecting rod is connected to the upper middle part of the fixed prop, specifically, it is connected to two-thirds of the upper part of the fixed prop.

[0075] For the fixing method of the connecting rod on the fixed prop, one example is: pin holes can be set on the two flanges of the I-beam at two-thirds of the upper part of the fixed prop, and pin holes are set at the first end of the connecting rod. The connecting pins are respectively passed through the pin holes of the fixed prop and the pin holes at the first end of the connecting rod to connect the first end of the connecting rod to the fixed prop, and the connecting pins transfer and bear the forces in two directions of the solid prop and the roadway roof. This method has a simple structure, but the shear force on the connecting pins is relatively large, and drilling pin holes on the two flanges of the fixed prop affects the strength. During construction, it is very difficult to ensure that the cap notch constructed on the roadway roof is at a distance from the upper middle part of the fixed prop that is exactly suitable for the length of the connecting rod, so the construction is slightly difficult.

[0076] For the fixing method of the connecting rod on the fixed support, another example is as follows: Set an auxiliary support. The height of the auxiliary support is two-thirds of the height of the fixed support, and the bottom end of the auxiliary support is supported on the upper side of the roadway in the mining area. After the fixed support and the connecting rod are installed in place, the top end of the auxiliary support is supported on the first end of the connecting rod, so that the end of the first end of the connecting rod is abutted within the two flanges of the fixed support.

[0077] For the fixing method of the connecting rod on the fixed support, another example is: Refer to Figure 2 , Figure 4 , Figure 5 , there is a first cable bolt 13 set on the working face roof. The first cable bolt is set vertically, and the front end of the first cable bolt is driven into the working face roof 1. A long strip hole 20 for the cable bolt to pass through is set on the web at two-thirds of the upper part of the fixed support (when the I-beam is used for support, the two flanges mainly resist the bending moment, so opening a long strip hole on the web has little impact on the I-beam support); anchor holes are set on the webs at the first end and the second end of the connecting rod; the tail end of the first cable bolt faces downward. After passing through the long strip hole 20 of the fixed support, it is anchored at the first end of the connecting rod. In this way, the distance that the tail end of the cable bolt exposes from the working face roof is relatively long. The bolt is not subjected to lateral shear force and only receives a downward tensile force. The impact force of part of the sliding gangue on the fixed support is transferred by the connecting rod and is not completely borne by the cable bolt. Therefore, the pressure borne by the bolt is reduced.

[0078] Refer to Figure 2 , Figure 3 , in order to prevent the rib spalling of the upper side of the roadway in the mining area (rib spalling refers to the phenomenon that the side wall of the roadway in the mining area, due to the action of mine pressure, causes the coal wall or rock to deform, break and fall off. This phenomenon usually occurs when there is a suspension in the roof rock formation of the goaf area and the pressure is transferred to the upper side of the roadway in the mining area, resulting in an increase in the pressure borne by the upper side of the roadway in the mining area and being crushed), drive the third cable bolt 9 into the upper side of the roadway in the mining area to support the upper side 10 of the roadway in the mining area; specifically in implementation, at least one row of bolts also needs to be driven into the upper side of the roadway in the mining area, and one row of bolts or cable bolts needs to be driven downward into the roof of the goaf area for fixing the upper side of the roadway in the mining area.

[0079] Refer to Figure 2 , Figure 3 , at the same time, multiple other rows of cable bolts and bolts also need to be applied to the roof and the lower side of the roadway in the mining area. The roof of the roadway in the mining area is supported by resin bolts, cable bolts and anchor nets. The bolt spacing and row spacing are both 800 mm, and the cable bolt spacing and row spacing are both 2400 mm; the upper side and the lower side of the roadway in the mining area are supported by resin bolts and anchor nets. The bolt spacing and row spacing are both 800 mm. The bolt diameter is 18 mm and the length is 1800 mm; the cable bolt diameter is 17.8 mm and the length is 5200 mm.

[0080] At the same time, between the roof of the roadway in the mining area and the roof, another row of hydraulic supports also needs to be applied, which is supported at the middle position of the roadway in the mining area and the hydraulic support inclines forward by 12° (forming a 12° angle with the vertical direction).

[0081] Bolting wire meshes 19 are arranged on the roof 15 of the roadway along the face, the upper rib 10 of the roadway, and the lower rib 11 of the roadway. The bolting wire meshes 19 are pressed against the rock wall by T-shaped steel straps 18. The T-shaped steel straps 18 are arranged along the roof of the roadway along the face to the lower rib of the roadway starting from the second end of the connecting rod; the T-shaped steel straps are tightened by anchor cables and anchor bolt trays and supported by the tops of hydraulic props.

[0082] Example 2:

[0083] The construction method of the gob-side entry retaining gangue retaining and support facilities for non-pillar mining of the present invention includes construction in the advanced stage and construction in the lagging stage.

[0084] Among them, the construction in the advanced stage should be carried out when the advancing distance of the working face of the coal mining face is not less than 50 m. The construction in the advanced stage includes the following steps:

[0085] Before the coal mining face advances, a prop notch is constructed on the floor 2 of the working face, and a cap notch 24 adapted to the cap is constructed on the roof 15 of the roadway along the face.

[0086] Anchor holes are drilled in the upper rib 10 of the roadway along the face, the roof 15 of the roadway along the face, and the cap notch 24; anchor holes are drilled in the roof 1 of the working face.

[0087] Then, the bolting wire meshes 19 and the T-shaped steel straps 18 are installed. A blank for installing the cap is reserved on the bolting wire mesh. The T-shaped steel straps are tightened by the trays of each anchor cable and anchor bolt, and the bolting wire mesh is pressed against the rock wall. When constructing the anchor bolts, an MQT-13 type anchor bolt machine is used to drill the anchor bolt holes. The diameter of the drilled holes of the anchor bolt holes is 28 mm, and the depth of the anchor bolt holes is 50 - 100 mm shorter than the total length of the anchor bolt body. The coal and rock powder in the drilled anchor holes must be cleaned clean, without accumulated water and debris.

[0088] Install resin anchor bolts. Use an MSK-2350 resin cartridge to continuously stir at a constant speed for 8 - 15 s and then stop. After the stirring stops, wait for another 41 - 90 s until the gel retreats and then withdraw the anchor bolt drill. After the waiting time of the anchoring agent reaches 5 min, the anchor bolt drill can be used to tighten the nut until the tail of the anchor bolt pops out the plastic pad, the tray is close to the wall surface, and the length of the anchor bolt exposed from the nut is 10 mm - 50 mm; the pre-tightening torque of the anchor bolt nut shall not be less than 120 N·m; and shall not be greater than 150 N·m.

[0089] Install the cap 16 and the connecting rod 7. The right-angled wedge of the cap passes through the blank and is inserted into the cap notch 24. The cap brim 23 presses the bolting wire mesh 19. The second anchor cable 14 passes through the cap 16, the end of the second end of the connecting rod, and the T-shaped steel strap, and then the second anchor cable 14 is tensioned and tightened.

[0090] Insert the lower end of the fixed support column 3 into the support column notch and connect the upper end to the roof. After placing the first end of the connecting rod in the upper-middle position of the fixed support column, pass the first cable through the long hole 20 of the fixed support column, then through the first end of the connecting rod, and then tension and clamp the first cable 13. The fixed support columns constructed must be placed on solid ground and ensure a strong uphill force. At the same time, install the third cable 9.

[0091] Install the hydraulic support column 4. The initial support force of the hydraulic support column shall not be less than 90 KN. The hydraulic support column must be tied with an anti-toppling rope to prevent injury caused by the pressure relief of the support column. One of the hydraulic support columns is supported below the second end of the connecting rod. A wooden cushion block 17 is provided between the top end of the hydraulic support column and the connecting rod. Utilizing the soft characteristics of the wooden cushion block, the top end of the hydraulic support column is adapted to the complex structural surface at the supported location.

[0092] Among them, the construction in the lag phase includes the following steps:

[0093] Tighten the tail end of the first cable 13 again. Due to mining influence and the stress released by the cable, there is a movement allowance. Tension and clamp the generated movement allowance, and remove the hydraulic support column 4; also tighten the tail end of the second cable 14 again.

[0094] After the gob floor cutting pressure relief, tighten the tail end of the second cable 14 again.

[0095] During cable construction, the cable shall be installed as it is drilled (i.e., start installing the cable as soon as a cable hole is drilled). After the cable is drilled, the T-shaped steel strip must be fixed first and then the cable tail end locking device is installed, and tension it in time to prevent the T-shaped steel strip from sliding down and injuring people. Before tensioning the cable, check whether there is looseness at the oil circuit joints of the tensioning jack and the oil pump. If looseness is found, tighten it in time. When tensioning the cable, the tensioning cylinder shall be coaxial with the cable. After tensioning, the length of the cable tail end exposed outside the locking device is 150 mm - 250 mm.

[0096] Using the facilities and construction plan of the present invention, an experimental implementation was carried out. After the implementation, a set of monitoring points for the roof-to-floor and upper-lower rib convergence of the machine roadway were set at every 30 m in the machine roadway, and a set of roof separation monitoring points of the machine roadway were set at every 50 m. Observe the change situation once a week and record it in the on-site ledger. At the end of each month, submit the records of all monitoring points to the production technology section for filing and use as the basis for analysis. The following Table 1 was obtained:

[0097] Table 1: Observation table for gob-side entry retaining:

[0098] Monitoring table for roof-to-floor and rib convergence in the gob-side entry retaining section (monitored once a week)

[0099]

[0100] As can be seen from Table 1 above: The effect of the present invention is relatively good. The maximum movement of the roof is 78 mm, and the maximum convergence of the upper and lower sides of the roadway is 138 mm. There are no safety accidents during the experimental implementation.

[0101] The above is an exemplary description of the present invention and does not represent the protection scope of the present invention.

Claims

1. The gob-side entry retaining gangue blocking and support facilities for pillarless mining are installed at the machine roadway of the steeply inclined coal seam and the lower outlet of the coal mining face, and support this area; among them, the lower outlet of the coal mining face has a working face floor inclined at 35° - 55° to the horizontal plane and a working face roof parallel to the working face floor; the upper side and the lower side of the machine roadway are vertically arranged, and the roof of the machine roadway and the roof of the working face are on the same plane; It is characterized in that It includes: A fixed support pillar arranged between the working face floor and the working face roof, with the top inclined towards the machine roadway, used to block the sliding pressure of the gangue in the goaf; A connecting rod is provided to connect the upper middle part of the fixed support pillar to the roof of the machine roadway. The connecting rod has a first end of the connecting rod at the connection with the fixed support pillar and a second end of the connecting rod at the connection with the roof of the machine roadway; specifically, the first end of the connecting rod is connected to two-thirds of the fixed support pillar from bottom to top; The connecting rod supports from the upper middle part of the fixed support pillar to the roof of the machine roadway; it is used to offset part of the pressure exerted by the gangue parallel to the coal mining face towards the machine roadway and part of the vertically downward pressure of the roof of the machine roadway; The working face roof is provided with a first cable bolt. The front end of the first cable bolt is driven into the working face roof, and the tail end passes downward through the fixed support pillar and is anchored at the first end of the connecting rod; The roof of the machine roadway is provided with a second cable bolt. The front end of the second cable bolt is driven into the roof of the machine roadway, and the tail end is anchored at the second end of the connecting rod.

2. The gob-side entry retaining gangue blocking and support facilities for pillarless mining according to claim 1, characterized in that, Between the floor of the machine roadway and the roof of the machine roadway, a hydraulic support pillar is detachably arranged. Specifically, it is advanced and supported between the floor of the machine roadway and the roof of the machine roadway before the coal mining face advances, and is removed after the coal mining face advances; Among them, it includes a hydraulic support pillar supported below the second end of the connecting rod, and a wooden cushion block is arranged between the top end of the hydraulic support pillar and the connecting rod.

3. The gob-side entry retaining gangue blocking and support facilities for pillarless mining according to claim 1, characterized in that, The first cable bolt is vertically arranged.

4. The gob-side entry retaining gangue blocking and support facilities for pillarless mining according to claim 3, characterized in that, At the connection of the connecting rod and the roof of the machine roadway, a column cap is arranged; The column cap is a right-angled wedge protruding upward, used to embed into the roof of the machine roadway; Below the wedge is a right-angled wedge-shaped groove, and the end wedge formed by the intersection of the upper surface and the end surface of the second end of the connecting rod is inserted into the wedge-shaped groove; One of the surfaces forming the right-angled wedge has an anchor hole through which a second bolt passes. The tail end of the second cable bolt passes through the anchor hole and is anchored at the second end of the connecting rod; Both sides of the right-angled wedge have brims for fitting the roof of the machine roadway.

5. The gob-side entry retaining gangue blocking and support facilities for pillarless mining according to claim 3, characterized in that, A T-shaped steel strip is arranged on the roof of the machine roadway, and it is arranged along the roof of the machine roadway from the second end of the connecting rod to the lower side of the roadway; An anchor mesh is arranged on the roof of the machine roadway, the upper side of the roadway, and the lower side of the roadway, and is pressed against the rock wall by the T-shaped steel strip.

6. The gob-side entry retaining gangue blocking and support facilities for pillarless mining according to claim 3, characterized in that, The fixed support pillar is an I-beam, and a long hole for the cable bolt to pass through is arranged on the web at two-thirds of the upper part of the fixed support pillar; The connecting rod is an I-beam, and anchor holes for the cable bolt to pass through are arranged on the webs at the first end and the second end of the connecting rod; The distance between the outer sides of the two flanges of the I-beam of the connecting rod is smaller than the distance between the inner sides of the two flanges of the I-beam of the fixed support pillar, so that the connecting rod can be inserted into the two flanges of the fixed support pillar.

7. The gob-side entry retaining gangue and support facilities for pillarless mining according to claim 3, characterized in that: The connecting rod is horizontally arranged; The top end of the fixed support inclines towards the machine roadway, so that an included angle of 70° - 80° is formed between the fixed support and the working face floor; The third anchor cable is driven into the upper side of the machine roadway in the direction perpendicular to the upper side of the machine roadway to support the upper side of the machine roadway.

8. Construction method of gob-side entry retaining gangue and support facilities for pillarless mining, which is used for constructing the gob-side entry retaining gangue and support facilities for pillarless mining described in any one of claims 1-7, characterized in that, It includes the construction in the advanced stage and the construction in the lagging stage; Among them, the construction in the advanced stage includes the following steps: Before the coal mining face advances, a support notch is constructed on the working face floor, and a cap notch adapted to the cap is constructed on the machine roadway roof, Anchor holes are driven into the upper side of the machine roadway and the cap notch of the machine roadway roof; The second anchor cable, the third anchor cable and the cap are installed; The lower end of the fixed support is inserted into the support notch, and the upper end abuts against the roof; the middle and upper part of the fixed support is connected to the first end of the connecting rod, and the second anchor cable passes through the cap and is tensioned and clamped; The hydraulic support is supported below the second end of the connecting rod; Among them, the construction in the lagging stage includes the following steps: The hydraulic support is removed; the slack generated at the tail end of the second anchor cable is tensioned and clamped; After the goaf is cut-bottom pressure-relieved, the slack generated again at the tail end of the second anchor cable is tensioned and clamped.

9. The construction method according to claim 8, characterized in that, It also includes the following steps: Before the coal mining face advances, anchor holes are driven into the working face roof, and the first anchor cable is installed; After the first anchor cable passes through the middle and upper part of the fixed support, it is connected to the end of the connecting rod and tensioned and clamped; Among them, the construction in the lagging stage also includes the following steps: the slack generated at the tail end of the first anchor cable is tensioned and clamped, and then the hydraulic support is removed.

10. The construction method according to claim 8, characterized in that, It also includes the following steps: Before installing the cap, first install the anchor mesh, leave a blank for installing the cap on the anchor mesh, the right-angled wedge of the cap passes through the blank and is inserted into the cap notch, and the cap edge presses the anchor mesh; After the second anchor cable passes through the cap, it passes through the second end of the connecting rod, passes through the T-shaped steel strip, and then the end of the second anchor cable is tensioned and clamped.

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