Coal mining tunnel support facilities and construction methods

Abstract

The invention discloses a coal mining tunnel support facility and a construction method, wherein the support facility includes anchor rods, anchor cables, and anchor nets of the tunnel upper wall, tunnel lower wall, and tunnel roof. It also includes laying a reinforcement net composed of steel bars interwoven vertically and horizontally on the straight roof. An arched top beam is arranged at the curved roof, and the two ends of the arched top beam are respectively fixed on the straight roof and the tunnel upper wall. The construction of the invention includes the steps of installing anchor rods, anchor cables, and anchor nets; hanging a reinforcement net under the straight roof; and installing an arched beam under the curved roof. The invention strengthens the curved roof of the tunnel that is easy to deform and the support of the tunnel upper wall, and utilizes the characteristics of the straight roof section with a low moving speed and small deformation to disperse the deformation pressure of part of the curved roof to the straight roof through the arched beam to maintain the force balance of the tunnel. The straight roof is also guaranteed to be intact by arranging a reinforcement net. The invention adjusts the axial force of the anchor rods and anchor cables, arranges the anchor rods and anchor cables in the tunnel as a whole, and uses the tunnel support balance.

Description

Technical Field

[0001] The invention relates to a coal mining technology, in particular to a supporting technology for coal mining tunnels. Background Art

[0002] For thin coal seams with a thickness of about 1 meter and steeply inclined coal seams, in order to cooperate with the mining technology, the coal mining tunnels are all excavated in the coal seams, which are semi-coal tunnels. The cross-section of the semi-coal tunnel is composed of an arc-shaped roof section and a straight roof section. Among them, the cross-section of the excavated coal seam is an arc-shaped roof, and the arc-shaped roof is mainly composed of coal seams. Since the coal seams are relatively fragile, they are easy to collapse after excavation, so they are set to an arc shape (vault shape) to better cope with roof deformation. Among them, the straight roof is set along the lower surface of the pseudo-roof, and the pseudo-roof rock layer is complete, easy to maintain, and not easy to deform. The upper wall and the lower wall of the tunnel are vertical, the side of the arc-shaped roof is the upper wall of the tunnel, and the side of the straight roof is the lower wall of the tunnel.

[0003] The mechanical conditions of the mining tunnel in steeply inclined thin coal seams are as follows:

[0004] Analyzing the distribution law of the vertical stress field around the tunnel, there is obvious vertical stress and horizontal stress concentration on the upper wall of the tunnel. If the support strength is insufficient, it is easy to deform.

[0005] The entire tunnel upper wall and roof shifted along the inclination of the rock strata, and one side of the straight roof section moved at a lower speed while the roof was intact.

[0006] From the perspective of the axial force on the anchor rods and cables, the anchor rods and cables near the false top of the top plate, the upper side anchor rods and the lower side anchor rods are subject to large tensile stress; from the perspective of the shear force on the anchor rods and cables, the anchor rods and cables near the false top of the top plate, the upper side anchor rods and the lower side anchor rods are subject to large shear stress, and if the support strength is insufficient, they are prone to deformation.

[0007] Analyzing the plastic failure of the tunnel surrounding rock, the failure mainly occurred in the top plate and upper wall of the arc section.

[0008] There are many steeply inclined thin coal seams in the southwest of my country. If the support strength of the mining tunnel is too low, the deformation of the tunnel cannot be effectively controlled. During the mining period, the deformation of the tunnel roof and bottom plates and the two sides is large and the support is difficult. This problem is particularly prominent during the mining of the working face. The surrounding rock control of this type of tunnel has become the main factor restricting the safe and efficient production of mines. Therefore, it is urgent to reform the existing support scheme of the mining tunnel to promote safe production and improve the economic benefits of mines. Summary of the invention

[0009] In order to solve the above problems, the present invention provides coal mining tunnel support facilities and construction methods.

[0010] The coal mining tunnel support facility of the present invention is arranged in the coal mining tunnel, which is a semi-coal tunnel arranged in a steeply inclined thin coal seam, and has a straight roof arranged along the lower surface of the pseudo roof and an arc-shaped roof arranged to dig the cross section of the coal seam. The upper wall of the tunnel is vertically arranged between the arc-shaped roof and the tunnel bottom plate, and the lower wall of the tunnel is vertically arranged between the straight roof and the tunnel bottom plate.

[0011] It includes anchor rods and anchor cables installed on the upper wall, lower wall and roof of the tunnel, as well as anchor nets hung at the tail ends of the anchor rods and anchor cables and partially covering the tunnel wall.

[0012] The straight roof plate is driven into the rock mass with a row of anchor cables and four rows of anchor rods, and penetrates into the old roof.

[0013] Two rows of anchor cables and three rows of anchor rods are driven into the rock mass on the curved roof and the upper wall of the tunnel.

[0014] Two rows of anchor rods are driven into the rock mass at the lower wall of the tunnel.

[0015] A row of anchor rods are driven into the rock mass at the junction of the curved roof and the upper wall of the tunnel.

[0016] Anchor nets are laid on the upper wall and curved roof of the tunnel and hung at the tail ends of each anchor rod\anchor cable.

[0017] The straight top plate is paved with a reinforcement mesh composed of crisscrossing steel bars, and both ends of the steel bars are hung on the tail ends of the anchor rods and cables.

[0018] An arched top beam is arranged on the lower surface of the anchor net at the arc-shaped top plate, and the two ends of the arched top beam are respectively fixed on the flat top plate and the upper wall of the tunnel. The arched top beam is composed of at least two sections, including a left arch beam section and a right arch beam section, which are hinged by a movable joint and can rotate relative to each other, and the rotation range is that the angle between the left arch beam section and the right arch beam section at the bottom is less than 180°.

[0019] The coal mining tunnel support facilities as described above are further described as follows: a row of anchor cables driven into the rock body from the straight roof plate is arranged in the center of the straight roof plate and is perpendicular to the straight roof plate, and four rows of anchor rods driven into the rock body from the straight roof plate are evenly spaced on the straight roof plate, of which three rows of anchor rods are perpendicular to the straight roof plate, and a row of anchor rods close to the curved roof plate is inclined toward the curved roof plate.

[0020] The two rows of anchor cables of the arc-shaped top plate are evenly distributed on the arc-shaped top plate and inclined toward the straight top plate. The three rows of anchor rods of the arc-shaped top plate are evenly distributed on the arc-shaped top plate, and the anchor rods are perpendicular to the arc tangent of the arc-shaped top plate.

[0021] The two rows of anchor cables on the upper side of the tunnel are evenly distributed on the upper side of the tunnel, and the anchor cables close to the tunnel bottom plate are inclined toward the tunnel bottom plate. The anchor cables close to the tunnel top plate are inclined toward the tunnel top plate. The three rows of anchor rods on the upper side of the tunnel are evenly distributed on the upper side of the tunnel at equal intervals, and the middle anchor rod is perpendicular to the upper side of the tunnel. The anchor rods close to the tunnel bottom plate are inclined toward the tunnel bottom plate. The anchor rods close to the tunnel top plate are inclined toward the tunnel top plate.

[0022] The two rows of anchor rods on the lower wall of the tunnel are evenly distributed on the lower wall of the tunnel. The anchor rods close to the tunnel bottom plate are inclined toward the tunnel bottom plate. The anchor rods close to the tunnel top plate are inclined toward the tunnel top plate.

[0023] A virtual connecting line is drawn between the two end points of the arc passing through the arc-shaped roof, and the virtual connecting line forms an angle with the upper wall of the tunnel. The anchor rod at the connection between the tunnel roof and the upper wall of the tunnel is driven into the rock mass along the direction of the bisector of the angle.

[0024] The above-mentioned coal mining tunnel support facility is further described as follows: the anchor net is laid from the junction of the tunnel upper wall and the tunnel roof, covers the curved roof, and then extends to the tail end of a row of anchor rods in the straight roof close to the curved roof. The anchor net is hung at the tail end of each anchor rod\anchor cable.

[0025] The above-mentioned coal mining tunnel support facility is further described as follows: hooks are arranged at both ends of the steel bars, and a square tray is hung at the tail end of the anchor rod or anchor cable. The tray is a flat plate perpendicular to the anchor cable and the anchor rod, and a number of columns are arranged vertically upward at the four corners of the tray. The upper end of the column is a cone tip that penetrates into the rock mass. The hook is overlapped on the column.

[0026] A reinforcing rib is arranged between the two adjacent and parallel steel bars. The reinforcing rib is composed of connecting hooks at both ends and a connector connecting the connecting hooks at both ends. The front end of the connecting hook is a hook, the rear end is a screw rod, and the connector is an inner thread sleeve, and the left and right ends of the inner thread sleeve are respectively provided with a left-hand thread and a right-hand thread.

[0027] The coal mining tunnel support facility as described above is further described as follows: the arched top beam is composed of a right section of the arch beam near one end of the straight top plate, and a left section of the arch beam near one end of the tunnel upper wall.

[0028] The arc length of the arc top plate is evenly divided into four parts, and the hinge point between the right section of the arch beam and the left section of the arch beam is set at any position between one quarter and two quarters close to the straight top plate.

[0029] The hinged joint is provided with a limit card which makes the included angle between the left section of the arch beam and the right section of the arch beam at the bottom smaller than 180°.

[0030] The tail end of the left section of the arch beam is provided with a turning angle that is consistent with the angle between the tunnel roof and the tunnel upper wall, so that the tail end of the left section of the arch beam is attached to the tunnel upper wall surface.

[0031] A plurality of anchor rod / anchor cable hanging holes are arranged on the arched top beam, which are used to fix the arched top beam to the tail ends of the anchor rods / anchor cables at corresponding locations.

[0032] The coal mining tunnel support facility as described above is further described as follows: an arch beam sleeve is embedded in the straight roof near the intersection of the curved roof and the straight roof, and the end of the right section of the arch beam is an elbow, which is inserted into the arch beam sleeve.

[0033] A sleeve embedding hole for installing an arch beam sleeve is arranged in the flat top plate, and an anchor cable is driven into the sleeve embedding hole to the old top.

[0034] A fixing surface roughly perpendicular to the anchor cable is provided in the arch beam sleeve, and the tail end of the anchor cable is pulled on the fixing surface.

[0035] An adhesive layer is arranged around the arch beam sleeve to bond the arch beam sleeve to the sleeve embedding hole.

[0036] Among them, the construction method of the coal mining tunnel support facility provided by the present invention is used to construct the coal mining tunnel support facility in the above-mentioned invention content, and the specific steps are as follows:

[0037] (1) After the tunnel is excavated, the exposed rock mass on the top of the tunnel is temporarily supported. Then, anchor rods and anchor cable holes are driven into the curved roof.

[0038] (2) A sleeve embedding hole is driven into the straight top plate near the intersection of the curved top plate and the straight top plate, and then an anchor cable hole is driven into the old top from the bottom of the sleeve embedding hole.

[0039] (3) Anchor rods and anchor cables are arranged in the anchor rod / anchor cable holes driven in step (1), and anchor cables are arranged in the anchor cable holes driven in step (2). An anchor net is hung at the tail end of the anchor rod / anchor cable of the curved top plate.

[0040] (4) A cement release agent is applied to the tail end of the anchor cable in the sleeve embedding hole, the arch beam sleeve according to claim 5 is arranged in the sleeve embedding hole, and the tail end is pulled onto the fixed surface for pre-tightening.

[0041] (5) Pour concrete into the sleeve embedding hole to fix the arch beam sleeve.

[0042] (6) Anchor rods and anchor cables are installed on the flat top plate.

[0043] (7) Hang a reinforcing net at the tail end of the anchor rod or anchor cable on the straight top plate.

[0044] (8) Install an arched beam below the anchor net at the curved top plate.

[0045] (9) Anchor rod and anchor cable holes are driven into the upper and lower sides of the tunnel, and anchor rods and anchor cables are set in the holes and fixed by grouting.

[0046] The construction method of the coal mining tunnel support facilities as described above is further described as follows:

[0047] (1) The sleeve embedding hole is specifically: a sleeve embedding hole having a hole diameter equal to the diameter of the circumscribed circle of the arch beam sleeve and a depth greater than the length of the arch beam sleeve is driven into the flat top plate in a direction perpendicular to the flat top plate.

[0048] (2) Punch the anchor hole from the bottom of the sleeve embedded hole to the old top. Specifically, first open a lower notch with a width greater than the diameter of the anchor hole drill rod at the lower edge of the sleeve embedded hole. Then, pass the anchor hole drill rod through the lower notch and push it into the bottom of the sleeve embedded hole. Punch the anchor hole to the old top at an angle inclined toward the arc-shaped top plate.

[0049] (3) The tail end of the anchor cable embedded in the sleeve hole is pulled on the fixed surface for pre-tightening, and the specific pre-tightening force is 20-40KN.

[0050] (4) The concrete is poured into the sleeve embedding hole to fix the arch beam sleeve. The specific steps are as follows:

[0051] a. Inject concrete into the gap between the fixing surface and the bottom of the sleeve embedding hole. Inject concrete into the gap between the sleeve embedding hole and the outer surface of the arch beam sleeve.

[0052] b. 30 minutes after the concrete is injected, the pre-tightening sleeve is embedded in the anchor cable in the hole to make the pre-tightening force 40-70KN.

[0053] c. 3 hours after concrete injection, pre-tighten the anchor cable again so that the pre-tightening force is above 150KN.

[0054] As mentioned above, a reinforcement net is hung at the tail end of the anchor rod or anchor cable of the flat top plate, specifically:

[0055] a. Put the pallet into the tail end of the anchor rod / anchor cable, and hang the steel bar hook on the pallet column.

[0056] b. After the entire flat top plate is equipped with steel bars, pre-tighten each pallet for the first time to a pre-tightening force of 20-40KN.

[0057] c. Pre-tighten each pallet a second time until the pre-tightening force is not less than 150KN, until the pallet column is inserted into the rock mass.

[0058] d. Install reinforcing bars between the loose steel bars and the adjacent and parallel steel bars, and tighten the reinforcing bars.

[0059] As described above, the arched beam is installed below the anchor net at the curved top plate, specifically:

[0060] a. Insert the end of the right section of the arch beam into the arch beam sleeve to the bottom of the arch beam sleeve, and hang the hanging hole of the right section of the arch beam into the corresponding anchor rod\anchor cable tail end and initially insert the nut.

[0061] b. Then hinge the left section of the arch beam with the right section of the arch beam, and hang the hanging hole of the left section of the arch beam into the corresponding anchor rod\anchor cable tail end and initially insert the nut.

[0062] c. Starting from the right section of the arch beam to the left section of the arch beam, pre-tighten the nuts at the tail end of the anchor rod and anchor cable to a pre-tightening force of 40-70KN.

[0063] d. Start again from the right section of the pre-tightened arch beam to the left section of the arch beam and tighten the nuts at the tail end of the anchor rod and anchor cable to a pre-tightening force of more than 150KN.

[0064] Beneficial effects:

[0065] The invention strengthens the support of the easily deformed arc-shaped roof of the tunnel and the upper wall of the tunnel, overcomes the obvious vertical stress and horizontal stress concentration on the upper wall of the tunnel, and prevents the deformation of the tunnel.

[0066] The present invention utilizes the characteristics of the flat roof section with low moving speed and small deformation to disperse the deformation pressure of the part of the curved roof to the flat roof through the arched beam to maintain the force balance of the roadway. The integrity of the flat roof is ensured by setting a reinforcing net.

[0067] The present invention adjusts the axial force of the anchor rods and anchor cables, generally arranges the anchor rods and anchor cables in the tunnel, and uses the tunnel support balance.

[0068] From the analysis of the plastic failure of the tunnel surrounding rock, it is found that the failure mainly occurs in the arc-shaped roof and upper wall. The present invention disperses the deformation pressure of part of the arc-shaped roof to the straight roof through the arched beam to maintain the force balance of the tunnel.

[0069] The reinforcing net structure of the present invention is simple to set up, can effectively grasp the rock wall surface, and can tighten the reinforcing net through reinforcing ribs, so that the reinforcing net can effectively support the straight top plate and protect the integrity of the straight top plate. The reinforcing net is simple to construct, and reinforcing ribs are installed at necessary positions, and the installation process is simple.

[0070] Instruction Manual

[0071] Figure 1 This is a schematic diagram of the rock structure of the semi-coal tunnel.

[0072] Figure 2 It is a schematic diagram of the tunnel support structure of the present invention.

[0073] Figure 3 It is a schematic diagram of the reinforcing net structure of the present invention.

[0074] Figure 4 It is a schematic diagram of the connection between the pallet and the steel bar of the present invention.

[0075] Figure 5 It is a schematic diagram of the structure of the tray of the present invention.

[0076] Figure 6 It is a schematic diagram of the reinforcing rib structure of the present invention.

[0077] Figure 7 It is a structural schematic diagram of the present invention in which the arch beam sleeve is embedded in the straight top plate sleeve embedding hole, and the elbow is inserted into the arch beam sleeve.

[0078] Figure 8 The invention is a cross-sectional schematic diagram showing that the arch beam sleeve is embedded in the straight top plate sleeve embedding hole, and the elbow is inserted into the arch beam sleeve.

[0079] Fig. 9 It is a cross-sectional view of the arch beam sleeve of the present invention.

[0080] Fig.10 It is a schematic diagram of the arched beam structure of the present invention.

[0081] Fig.11 2 is a structural diagram of an arched beam according to another example of the present invention.

[0082] Among them: false roof 1; coal seam 2; upper wall of tunnel 3; lower wall of tunnel 4; curved roof 5; straight roof 6; anchor cable 7; anchor rod 8; arch top beam 9; reinforcing mesh 10; steel bar 11; tray 12; reinforcing rib 13; column 14; connecting hook 15; inner thread sleeve 16; right section of arch beam 17; elbow 18; arch beam sleeve 19; sleeve embedding hole 20; concrete 21; lower notch 22; fixing surface 23; tail end of left section of arch beam 24; hanging hole 25; left section of arch beam 26; hinge pin 27; pull rod 28. DETAILED DESCRIPTION

[0083] The tunnel excavated in the following example experiment of the present invention belongs to the mining tunnel, which adopts the integration of machine and track to meet the requirements of coal and material transportation, equipment installation, pedestrians, ventilation, etc. during the production of the corresponding coal mining working face. The total length of the tunnel design is 960m, the service life is 5 years, and the tunnel slope is +5‰. This example experiment excavated 100m. Because the coal seam with an inclination angle greater than 45° during underground mining is a steeply inclined coal seam, taking the coal seam of 45° as an example, the straight roof 6 is inclined to 45°.

[0084] The coal seam in this example contains 1 to 2 layers of interlayers, with the total thickness of interlayers ranging from 0.08 to 0.15 m. The average thickness of the coal seam is 1.05 m, the average inclination is 51°, the coal is bright, the hardness is f = 2-3, the specific gravity is 1.45 t / m3, the mining index is 1.0, the coal seam variation coefficient is 34%, and it is a relatively stable coal seam. The coal seam in some parts of the working face is broken and easy to collapse, and the mine pressure is relatively large.

[0085] The strength index of the old roof rock sample of the mining tunnel is 2.06MPa, and the compressive strength is 49.24MPa. The strength index of the direct roof rock sample is 1.50MPa, and the compressive strength is 52.66MPa. The strength index of the coal sample is 0.62MPa, and the compressive strength is 15.00MPa. The strength index of the rock sample is 0.62~2.06MPa, the average strength index is 1.39MPa, the uniaxial compressive strength is 15.00~52.66MPa, and the average value is 38.97MPa.

[0086] According to on-site measurements, the tunnel surrounding rock has developed stratification, and the bonding strength between strata is low, among which the thickness of the old top stratification is about 15-25cm, the direct top is about 15-30cm, the coal seam 2 is about 30-50cm, and the floor is about 25-40cm. At the same time, the joints of the surrounding rock are also well developed, among which the coal seam has the largest degree of joint development, followed by the direct top, and the old top has the least.

[0087] refer to Figure 1 The coal mining tunnels in this embodiment are all excavated in the coal seam 2, which is a semi-coal tunnel. The cross section of the semi-coal tunnel is composed of 5 arc-shaped roof sections and 6 straight roof sections. Among them, the cross section of the excavated coal seam 2 is an arc-shaped roof 5, the arc-shaped roof 5 is mainly the coal seam 2, and the straight roof 6 is set along the lower surface of the pseudo roof 1. The straight roof 6 is set along the lower surface of the pseudo roof 1, and the pseudo roof 1 rock layer is complete. The upper wall 3 of the tunnel and the lower wall 4 of the tunnel are vertical, the upper wall 3 of the tunnel is on one side of the arc-shaped roof 5, and the lower wall 4 of the tunnel is on the side close to the straight roof 6.

[0088] The width of the tunnel is 4500mm, the upper wall height is 2450mm, and the lower wall height is 1510mm.

[0089] The supporting facilities are used to support the mining tunnel from the tunnel upper wall 3, tunnel lower wall 4, tunnel roof and tunnel floor. Figure 1 In the schematic diagram of the rock structure of the semi-coal tunnel, the left side of the tunnel is the upper wall 3 of the tunnel, and the right side is the lower wall 4 of the tunnel.

[0090] In this embodiment, the straight roof 6, which is called the tunnel roof, has a straight section length of about 3 meters in the tunnel section.

[0091] The other section of the tunnel roof is an arched section, the cross-section of which is an arc-shaped, and the radius of the arc is 3250 mm.

[0092] The basic support arrangement includes anchor rods and anchor cables of the tunnel upper wall 3, the tunnel lower wall 4, and the tunnel roof, and an anchor net hung at the tail ends of the anchor rods and anchor cables and partially covering the tunnel wall.

[0093] Example 1:

[0094] refer to Figure 2, the anchor cable 7 driven into the rock body by the straight roof plate 6 is arranged in the center of the straight roof plate 6 and is perpendicular to the straight roof plate 6. The four rows of anchor rods driven into the rock body by the straight roof plate 6 are evenly spaced on the straight roof plate 6, of which three rows of anchor rods 8 are perpendicular to the straight roof plate 6, and one row of anchor rods 8 near the curved roof plate 5 is inclined toward the curved roof plate 5, and the inclination angle is: forming an angle of 5° with the vertical line of the straight roof plate 6.

[0095] The two rows of anchor cables 7 driven into the rock body of the curved roof plate 5 are evenly distributed on the curved roof plate 5 and are inclined toward the straight roof plate 6 at an angle of 10° between the anchor cables 7 and the perpendicular line of the tangent. The three rows of anchor rods 8 driven into the rock body of the curved roof plate 5 are evenly distributed on the curved roof plate 5, and the anchor rods 8 are perpendicular to the curved tangent of the curved roof plate 5.

[0096] The two rows of anchor cables 7 driven into the rock mass from the upper wall 3 of the tunnel are evenly distributed on the upper wall of the tunnel. The anchor cables 7 close to the tunnel floor are inclined toward the tunnel floor, and the inclination angle is: forming an angle of 15° with the vertical line of the upper wall 3 of the tunnel. The anchor cables 7 close to the tunnel roof are inclined toward the tunnel roof, and the inclination angle is: forming an angle of 15° with the vertical line of the upper wall 3 of the tunnel.

[0097] The three rows of anchor rods 8 driven into the rock mass on the upper wall 3 of the tunnel are evenly distributed on the upper wall of the tunnel, and the middle anchor rod 8 is perpendicular to the upper wall of the tunnel. The anchor rods 8 close to the tunnel floor are inclined toward the tunnel floor, and the inclination angle is: forming an angle of 45° with the vertical line of the upper wall 3 of the tunnel. The anchor rods 8 close to the tunnel roof are inclined toward the tunnel roof, and the inclination angle is: forming an angle of 5° with the vertical line of the upper wall 3 of the tunnel.

[0098] Two rows of anchor rods 8 driven into the rock mass of the tunnel lower wall 4 are evenly distributed on the tunnel lower wall. The anchor rods 8 close to the tunnel bottom plate are inclined toward the tunnel bottom plate, and the inclination angle is: forming an angle of 5° with the vertical line of the tunnel lower wall 4. The anchor rods 8 close to the tunnel top plate are inclined toward the tunnel top plate, and the inclination angle is: forming an angle of 10° with the vertical line of the tunnel lower wall 4.

[0099] A row of anchor rods 8 are driven into the rock mass at the connection between the curved roof 5 and the upper wall 3 of the roadway. The specific driving angle is: a virtual connecting line is drawn between the two end points of the arc passing through the curved roof 5, and the virtual connecting line forms an angle with the upper wall 3 of the roadway, and the anchor rods 8 at the connection between the roadway roof and the upper wall 3 of the roadway are driven into the rock mass along the direction of the bisector of the angle.

[0100] Anchor nets are laid on the tunnel upper wall 3 and the curved roof 5. The anchor nets are laid from the connection between the tunnel upper wall 3 and the tunnel roof, and after covering the curved roof, they extend to the tail end of a row of anchor rods in the straight roof 6 close to the curved roof 5. The anchor nets are hung at the tail end of each anchor rod 8\anchor cable 7.

[0101] Technical parameters of anchor rods, anchor cables and anchor nets used in this embodiment:

[0102]

[0103] The anchor rods, grouting anchor cables, grouting materials and grouting equipment used in this plan are all made of materials produced by Shandong Anke Mine Support Technology Co., Ltd.

[0104] Example 2:

[0105] refer to Figure 3-6 A reinforcing mesh 10 composed of crisscrossed steel bars 11 is laid on the flat top plate 6, and both ends of the steel bars 11 are hung on the tail ends of the anchor rods and anchor cables.

[0106] Draw hooks are set at both ends of the steel bar 11, and a square tray 12 is hung at the tail end of the anchor rod or anchor cable. The tray 12 is a flat plate perpendicular to the anchor cable and the anchor rod. Four columns are vertically arranged at the four corners of the tray 12. The upper end of the column is a cone tip that penetrates into the rock mass. The draw hook is overlapped on the column.

[0107] The technical parameters of the square tray 12 used in this embodiment are as follows: length / width 150×150 mm, thickness 16 mm, wherein the column height is 40-50 mm, the column diameter is 20 mm, and the length of the portion inserted into the rock body is about 30-40 mm.

[0108] The diameter of the steel bar 11 is 8-12mm, preferably 10mm. The two ends of the steel bar 11 are directly bent to form hooks (circular ring shape, with an inner diameter slightly larger than 20mm). After the hooks are wound into a circular ring shape, it is best to weld them to prevent them from being straightened due to excessive stress. The length of the steel bar 11 is 600-1000mm. When used in this embodiment, since the spacing of the tail ends of the anchor rods and cables (including the row spacing and spacing: the spacing between adjacent anchor rods and cables in the horizontal direction, and the spacing between adjacent anchor rods and cables in the longitudinal direction) is set to 800mm, the spacing between the columns of the tray 12 at the tail ends of adjacent anchor rods and cables is calculated to be 626mm, so the spacing between the hooks of the steel bar 11 is 626mm.

[0109] A reinforcing rib is arranged between two adjacent and parallel steel bars 11. The reinforcing rib is composed of connecting hooks at both ends and a connector connecting the connecting hooks at both ends. The front end of the connecting hook is a hook, the rear end is a screw, and the connector is an inner screw sleeve 16, and the left and right ends of the inner screw sleeve 16 are respectively provided with a left-handed thread and a right-handed thread. The reinforcing rib is only used for pulling and connecting when the steel bar 11 is hung loosely, and its purpose is to tighten the steel bar 11. The hook center distance of the hooks at both ends of the reinforcing rib is adjustable through the inner screw sleeve 16, and the adjustment range is 600-900mm. The hook is a semicircular non-closed hook. The diameter of the reinforcing rib is 12-18mm, and 16mm is preferably used.

[0110] Example 3:

[0111] refer to Figure 7-11 The arched top beam 9 is mainly used to support the arc-shaped top plate 5 and is arranged on the lower surface of the anchor net below the arc-shaped top plate 5. The arched top beam 9 is composed of an arched beam left section 26 and an arched beam right section 17. The end close to the straight top plate 6 is the arched beam right section 17, and the end close to the upper wall 3 of the tunnel is the arched beam left section 26.

[0112] The left section 26 of the arch beam and the right section 17 of the arch beam are hinged by a movable joint and can rotate relative to each other. The range of rotation is to make the angle between the left section 26 of the arch beam and the right section 17 less than 180°. Preferably, the limit angle between the left section 26 of the arch beam and the right section 17 is 160°. Therefore, if the top plate of the arc section is deformed, when the arch beam is pressed from above, the deformation angle of the arch beam will not exceed 160° at most to prevent excessive deformation. The limit card at the hinge is set in various forms, but the main purpose is to prevent the angle from expanding beyond the limit. When the maximum limit angle is reached, the angle will no longer change.

[0113] Example 1 of setting the limit card at the hinge: Reference Fig.10 The left section 26 of the arch beam and the right section 17 of the arch beam intersect at the joint, and the same pin is passed through as a hinge pin 27. The right section 17 of the arch beam is provided with a fork after passing the hinge pin 27. The upper end of the fork extends forward and the lower end shrinks in a circular arc transition. The two side surfaces of the left section 26 of the arch beam are provided with limiting inclined surfaces that match the fork. The left section 26 of the arch beam narrows after passing the hinge pin 27, and the upper end extends forward and the lower end shrinks in a circular arc transition. The two side surfaces of the right section 17 of the arch beam are provided with limiting inclined surfaces that match the narrowing. Therefore, the expansion limit of the lower side angle of the left section 26 of the arch beam and the right section 17 of the arch beam in this way is 168°, and then the limiting inclined surfaces are in contact and cannot be expanded any further. The tightening limit of the lower side angle of the left section 26 of the arch beam and the right section 17 of the arch beam is 145°. The feature of the limit card structure used in this example is that the relative rotation angle between the left arch beam section 26 and the right arch beam section 17 is small, which will have certain restrictions on operation during installation and is relatively difficult to construct (compared to the limit card setting example 2), but this structure is relatively strong and can withstand greater pressure. The pressure bearing capacity of a single arch top beam 9 exceeds 3 tons.

[0114] Example 2 of setting the limit card at the hinge: Reference Fig.11The end of the left section 26 of the arch beam is an outer arc, and the right section 17 of the arch beam is an inner arc that embraces the outer arc of the left section 26 of the arch beam. The left section 26 of the arch beam and the right section 17 of the arch beam rotate relative to each other through the arc contact surface. Then, a tie rod 28 is arranged on both sides of the joint, and the two ends of the tie rod 28 are respectively hinged in the pin holes of the left section 26 of the arch beam and the right section 17 of the arch beam through pin holes, which are more than 300mm away from the arc contact surface, and the center distance of the pin holes at both ends of the tie rod 28 is smaller than the center distance of the pin holes of the left section 26 of the arch beam and the right section 17 of the arch beam when the left section 26 of the arch beam and the right section 17 of the arch beam are straight. Therefore, when the left section 26 of the arch beam and the right section 17 of the arch beam are unfolded to a certain angle, they are restricted by the tie rod 28 and cannot be further unfolded, but the angle is not restricted when it is tightened (until the left and right sections can overlap in the end). The characteristic of the limit card structure used in this example is that the relative rotation angle of the left section 26 of the arch beam and the right section 17 of the arch beam is free, which is more conducive to installation. However, the pressure that this structure can withstand depends on the tension borne by the pull rod 28 and the pin. In the current design, the pressure bearing capacity of a single arch top beam 9 is about 1.5 tons.

[0115] The hinge of the left section 26 of the arch beam and the right section 17 of the arch beam is set at the right position in the middle of the arc-shaped roof plate 5. According to calculation, its position is as follows: the arc length of the arc-shaped roof plate 5 is evenly divided into four parts, and the hinge of the right section 17 of the arch beam and the left section 26 of the arch beam is set at any position between one-quarter and two-quarters of the arc length of the straight roof plate 6. It is best that the hinge of the right section 17 of the arch beam and the left section 26 of the arch beam is set at one-quarter of the arc length of the arc-shaped roof plate 5 near the straight roof plate 6. From the analysis of the plastic failure of the surrounding rock of the tunnel, the failure mainly occurs in the arc-shaped roof plate 5 and the upper wall. Among them, the arc-shaped roof plate 5 is close to the side of the straight roof plate 6, which is most likely to cause the segregation of the star rock layer, because this part is close to the stratification of the coal seam 2 and the pseudo roof 1, so that the arc-shaped roof plate 5 is the coal seam suspension of the triangular area, and the arc-shaped roof plate 5 is close to the side of the straight roof plate 6 is the tip of the triangular area, so the roof here is most likely to deform.

[0116] The hinge of the right section 17 of the arch beam and the left section 26 of the arch beam is set here. When the top plate here deforms and generates pressure downward, the pressure is dispersed to the upper wall 3 and the straight top plate 6 of the tunnel through the arch beam. The upper wall 3 of the tunnel itself has deformation pressure. When the pressure of the top plate is dispersed to the upper wall 3 of the tunnel, it counteracts the pressure of the upper wall 3 of the tunnel to maintain the stability of the tunnel. Another part of the pressure of the top plate is transferred to the straight top plate 6 through the arch beam. Since the straight top plate 6 has good integrity, it can withstand the transferred pressure, and part of the pressure is transferred to the old top through the anchor cable, thus further ensuring the stability of the tunnel.

[0117] The arch beam is made of channel steel, and the specifications of the channel steel are: height 140mm, leg width 60mm, waist thickness 8mm. The right section 17 of the arch beam and the left section 26 of the arch beam are both arcs with a radius of 3550mm, and the straight-line distance between the two end points of the arch section of the middle section of the arch beam is 2900mm. The arch section of the middle section of the arch beam here refers to: excluding the elbow 18 of the right section 17 of the arch beam, and excluding the corner of the tail end of the left section 26 of the arch beam.

[0118] refer to Fig.10 The back is provided with an anchor rod / anchor cable hanging hole 25 corresponding to the tail end of the anchor rod / anchor cable at the corresponding position of the arc-shaped top plate 5, and is used to fix the arched top beam 9 to the tail end of the anchor rod / anchor cable at the corresponding position.

[0119] The tail end 24 of the left arch section 26 is provided with a turning angle consistent with the angle between the tunnel roof and the tunnel upper wall 3, so that the tail end 24 (length 185mm) of the left arch section 26 is attached to the wall surface of the tunnel upper wall 3. The end of the right arch section 17 is an elbow 18, the length of the elbow 18 is 300mm, and the elbow 18 forms an angle of 157° with the arc tangent of the right arch section 17 (the junction between the arc section and the elbow 18). The elbow 18 is inserted into the arch sleeve 19.

[0120] refer to Figure 7 The arch beam sleeve 19 is arranged in the straight top plate 6, and the specific position is near the intersection of the curved top plate 5 and the straight top plate 6. A sleeve embedding hole for installing the arch beam sleeve 19 is provided here. The sleeve embedding hole has a diameter of 230mm and a depth greater than 360mm. An anchor cable is driven into the sleeve embedding hole to the old top.

[0121] The arch beam sleeve 19 is square, with a depth of 350mm, an inner width of 148mm, an inner height of 160mm, and a wall thickness of 8mm.

[0122] refer to Figure 7 , 8 9. A fixing surface 23 approximately perpendicular to the anchor cable is provided in the arch beam sleeve 19. The fixing surface 23 is welded to the inner wall of the arch beam sleeve 19. Since the arch beam sleeve 19 is approximately perpendicular to the straight top plate 6, and the anchor cable is driven into the sleeve embedded hole to the old top, the anchor cable is inclined toward the arc top plate 5, and the inclination angle is: forming an angle of 15° with the vertical line of the straight top plate 6. The fixing surface 23 is perpendicular to the anchor cable, so the fixing surface 23 is also arranged inclined in the arch beam sleeve 19, and the tail end of the anchor cable is pulled on the fixing surface 23. A grouting notch is provided on the inner upper wall of the arch beam sleeve 19, and the grouting notch extends from the tail end of the arch beam sleeve 19 to the fixing surface 23, so that concrete can be poured from the grouting port into the gap behind the fixing surface 23 to make the gap compact.

[0123] An adhesive layer is arranged around the arch beam sleeve 19 to bond the arch beam sleeve 19 to the sleeve embedding hole. The adhesive layer is actually concrete 21, which fixes the arch beam sleeve 19 in the sleeve embedding hole.

[0124] Example 4:

[0125] The construction steps of the present invention are:

[0126] 1. Temporary support;

[0127] 2. Drill anchor rods and anchor cable holes in the curved top plate;

[0128] 3. Drill the hole for the sleeve to be embedded;

[0129] 4. Install anchor rods, anchor cables and anchor nets;

[0130] 5. Install the arch beam sleeve;

[0131] 6. Install anchor rods and cables on the straight top plate;

[0132] 7. A reinforcing net is hung under the flat top plate;

[0133] 8. Install an arched beam under the curved top plate;

[0134] 9. Install anchor rods and anchor cables on the upper and lower sides of the tunnel.

[0135] The specific steps of the above construction are as follows:

[0136] 1. Temporary support:

[0137] After the tunnel is cut, the exposed rock mass on the top of the tunnel will be temporarily supported by a metal front exploration beam. The distance between the temporary support and the top of the working face cannot be greater than 300mm.

[0138] 2. Drill anchor rods and anchor cable holes in the curved top plate:

[0139] The support of the present invention for the roof, especially the support of anchor rods, anchor cables and anchor nets, should be completed within the range of the head-on empty top distance. After the cutting cycle is completed, the newly exposed top side should be supported in time, and the lag time is not allowed to exceed 1 hour. The roof anchor rod construction is carried out in the order of the middle first and then the two sides; the drilling depth is 2300mm.

[0140] 3. Drill the sleeve embedding hole:

[0141] A sleeve embedding hole 20 is punched in the flat top plate 6 near the intersection of the curved top plate 5 and the flat top plate 6, and the sleeve embedding hole 20 is punched in a direction perpendicular to the flat top plate 6 by water drilling.

[0142] After the sleeve embedding hole 20 is drilled, a lower notch 22 is first cut at the lower edge of the hole mouth of the sleeve embedding hole 20. The width of the lower notch 22 can be larger than the diameter of the anchor hole drill rod. Because the center line of the anchor hole and the center line of the sleeve embedding hole 20 do not coincide, the two are greatly deflected. Therefore, the sleeve embedding hole 20 cannot extend into the anchor hole drill rod at the required angle. After setting the lower notch 22, the anchor hole drill rod can be passed through the lower notch 22 and pressed into the bottom of the sleeve embedding hole 20, and the anchor hole can be punched inward in the direction of the arc-shaped top plate 5 to the old top.

[0143] 4. Install anchor rods, anchor cables and anchor nets:

[0144] Anchor rods and anchor cables are set in the anchor rod / anchor cable holes driven in the above steps, and grouting is performed to fix them. An anchor net is hung under the arc-shaped top plate 5. An anchor net tray is set at the tail end of the anchor rod / anchor cable, and the anchor net is pressed against the rock surface through the anchor net tray.

[0145] The anchoring agent is installed in a fast and slow sequence. When the anchor bolt machine installs the anchor, when the anchor reaches the bottom of the hole, it is stirred and pushed forward, and the stirring is stopped after the stirring time required for the anchor is reached.

[0146] Anchor cable\anchor rod grouting:

[0147] The distance between the grouting equipment and the farthest grouting anchor rod / anchor cable should be within 10 meters.

[0148] Pour a certain amount of clean water into the mixing barrel as required, start the mixer, start slowly at the beginning, add the grouting material into the barrel, and stir while adding. The grouting material must be added slowly and stirred continuously. After the grouting material is added, the stirring time should be no less than 10 minutes.

[0149] Start the grouting pump for grouting. Start slowly and gradually increase the grouting flow rate.

[0150] When the grouting pump pressure reaches the maximum (7MPa), turn off the grouting pump and wait for 3 minutes before grouting again.

[0151] 5. Install the arch beam sleeve:

[0152] The tail end of the anchor cable in the sleeve embedding hole 20 is coated with a cement release agent to prevent the concrete from being combined with the anchor cable when it is poured into the gap behind the fixing surface 23 .

[0153] The arch beam sleeve 19 is placed in the sleeve embedding hole 20, and the tail end is pulled on the fixed surface 23 for pre-tightening, and the pre-tightening force is 20-40KN. After pre-tightening, the pores of the fixed surface 23 are blocked with waste paper or wood chips to prevent the concrete from flowing out when the concrete is poured.

[0154] Concrete with a water-cement ratio of about 0.5 is injected into the gap between the fixing surface 23 and the bottom of the sleeve embedding hole 20. After the gap is filled, concrete with less water is injected into the gap between the sleeve embedding hole 20 and the outer surface of the arch beam sleeve 19 to prevent the concrete from flowing out. If necessary, a baffle (concrete module) is added. The concrete is filled with a manual hand tool.

[0155] 30 minutes after the concrete is injected, the pre-tightening sleeve is embedded in the anchor cable in the hole 20, so that the pre-tightening force is 40-70KN. The anchor cable is moved during the concrete hardening process to prevent the concrete from combining with the anchor cable. 3 hours after the concrete is injected, the anchor cable is pre-tightened again (equivalent to moving the anchor cable again) so that the pre-tightening force is more than 150KN. In addition, the tail end of the anchor cable is coated with cement release agent, so the anchor cable and cement are in a separated state. The tension of the anchor cable is all borne on the fixed surface 23, and the tension can be adjusted by the nut at the tail end of the anchor cable.

[0156] The concrete in the filling sleeve embedding hole 20 uses quick-drying cement, which starts to harden within a few minutes, and the cement starts to harden in 10-20 minutes. The strength reaches more than 20MPa in 2h, about 30MPa in 4h, and more than 60MPa in 28 days.

[0157] The quick-drying cement has a micro-expansion property, so after being injected into the sleeve embedding hole, it can fully fill and tighten the gap through subsequent expansion.

[0158] 6. Install anchor rods and anchor cables on the straight top plate 6:

[0159] Anchor rods and anchor cables are drilled into the straight top plate 6, and anchor rods and anchor cables are set in the holes and fixed by grouting. The installation of anchor rods and anchor cables refers to the above (4. Installation of anchor rods, anchor cables and anchor nets).

[0160] 7. A reinforcement net 10 is hung under the flat top plate 6:

[0161] (1) Insert the pallet into the end of the anchor rod or anchor cable, and screw in the nut to prevent the pallet from falling. It is not necessary to tighten it. There should be at least 10mm gap between the upper end of the pallet column and the rock surface. The hook of the steel bar 11 is hung on the pallet column through this gap.

[0162] (2) After the entire flat top plate 6 is hung with pallets and steel bars 11, each pallet is pre-tightened to a pre-tightening force of 20-40KN. The column is partially nailed into the rock mass.

[0163] (3) Pre-tighten each pallet a second time to a pre-tightening force of not less than 150 kN, until all pallet columns are inserted into the rock mass, and the hooks of the steel bars 11 are pressed against the rock mass.

[0164] (4) Check whether there are any loose steel bars 11. Since the actual processing length of the steel bars 11 may be greater than the distance between the columns of two adjacent pallets, the steel bars 11 may not be tightened. Hang a reinforcing bar between the loose steel bar 11 and the adjacent and parallel steel bars 11, tighten the inner thread sleeve on the reinforcing bar, and tighten the reinforcing bar.

[0165] 8. Install an arched beam below the curved top plate 5:

[0166] Install the arched beam below the anchor net at the arc-shaped top plate 5, specifically:

[0167] When the arched beam is transported to the work site, it is transported in two sections (the left section of the arched beam and the right section of the arched beam).

[0168] (1) First install the right section 17 of the arch beam, insert the end of the right section 17 of the arch beam into the arch beam sleeve 19 to the bottom of the arch beam sleeve 19, and hang the hanging hole 25 on the back of the right section 17 of the arch beam into the corresponding anchor rod\anchor cable tail end and initially insert the nut to prevent the arch beam from falling.

[0169] (2) Then hinge the left section 26 of the arch beam with the right section 17 of the arch beam, insert the hinge pin 27, and hang the hanging hole 25 of the left section 26 of the arch beam into the corresponding anchor rod\anchor cable tail end and initially insert the nut to prevent the arch beam from falling.

[0170] (3) Pre-tighten the nuts at the tail end of the anchor rod and anchor cable from the right section 17 of the arch beam to the left section 26 of the arch beam until the background of the arch beam is basically attached to the rock surface. Due to the uneven rock surface, some sections cannot be attached, so there is no need to forcibly apply pre-tightening force. Check the gap between the back of the arch beam and the rock surface. If the gap is too large, add a block (such as a wood block or an iron block) in the gap to make the back of the arch beam and the rock surface close. Then, pre-tighten the nuts at the tail end of the anchor rod and anchor cable from the right section 17 of the arch beam to the left section 26 of the arch beam until the pre-tightening force is 40-70KN. When adding a block in the gap, it is not necessary to add a block to the entire back of the arch beam, but mainly to ensure that there is no gap at and near the tail end of the anchor rod and anchor cable.

[0171] (4) Start again from the right section 17 of the pre-tightened arch beam to the left section 26 of the arch beam, and tighten the nuts at the tail end of the anchor rod and anchor cable to a pre-tightening force of more than 150KN.

[0172] 9. Drive anchor rod / anchor cable holes in the upper side 3 and lower side 4 of the tunnel, set anchor rods and anchor cables in the holes, and fix them by grouting. The installation of anchor rods and anchor cables refers to the above (4. Install anchor rods, anchor cables, and anchor nets).

[0173] Supplementary explanation: The above embodiments can be combined with each other to form new embodiments.

[0174] The above is an example of the present invention and does not represent the protection scope of the present invention.

Claims

1. Coal mining roadway support facilities are arranged in the coal mining roadway, the coal mining roadway is a semi-coal roadway arranged in a steeply inclined thin coal seam, and has a straight roof arranged along the lower surface of the pseudo roof and an arc-shaped roof arranged to dig the cross section of the coal seam; the upper wall of the roadway is vertically arranged between the arc-shaped roof and the roadway bottom plate, and the lower wall of the roadway is vertically arranged between the straight roof and the roadway bottom plate; It includes anchor rods and anchor cables installed on the upper wall, lower wall and roof of the tunnel, and anchor nets hung at the tail end of the anchor rods and anchor cables and partially covering the tunnel wall; It is characterized in that The straight roof plate drives a row of anchor cables and four rows of anchor rods into the rock mass and penetrates the old roof; Two rows of anchor cables and three rows of anchor rods are driven into the rock mass on both the curved roof and the upper wall of the tunnel; Two rows of anchor rods are driven into the rock mass at the lower wall of the tunnel; A row of anchor rods are driven into the rock mass at the connection between the curved roof and the upper wall of the roadway; Anchor nets are laid on the upper wall and curved roof of the tunnel, and the anchor nets are hung at the tail ends of each anchor rod\anchor cable; The flat top plate is laid with a reinforcement mesh composed of crisscrossed steel bars, with both ends of the steel bars hung at the tail ends of the anchor rods and cables; An arched top beam is arranged on the lower surface of the anchor net at the arc-shaped top plate, and two ends of the arched top beam are respectively fixed on the flat top plate and the upper wall of the tunnel; the arched top beam is composed of at least two sections, including a left arched beam section and a right arched beam section, and the left arched beam section and the right arched beam section are hinged through a movable joint and can rotate relative to each other, and the rotation range is that the angle between the left arched beam section and the right arched beam section at the bottom is less than 180°; The arc length of the arc top plate is evenly divided into four parts, and the hinged part of the right section of the arch beam and the left section of the arch beam is set at any position between one quarter and two quarters of the straight top plate; the hinged part is provided with a limit card which makes the angle between the left section of the arch beam and the right section of the arch beam at the bottom less than 180°; The tail end of the left section of the arch beam is provided with a turning angle which is consistent with the angle between the tunnel roof and the tunnel upper wall, so that the tail end of the left section of the arch beam is attached to the tunnel upper wall surface; An arch beam sleeve is embedded in the straight top plate near the intersection of the curved top plate and the straight top plate. The end of the right section of the arch beam is an elbow, which is inserted into the arch beam sleeve. A sleeve embedding hole for installing the arch beam sleeve is provided in the straight top plate, and an anchor cable is driven into the sleeve embedding hole to the old top. A fixing surface roughly perpendicular to the anchor cable is provided in the arch beam sleeve, and the tail end of the anchor cable is pulled on the fixing surface.

2. The coal mining tunnel support facility according to claim 1, characterized in that: The row of anchor cables driven into the rock body by the straight top plate is arranged in the center of the straight top plate and is perpendicular to the straight top plate. The four rows of anchor rods driven into the rock body by the straight top plate are evenly spaced and distributed on the straight top plate, wherein three rows of anchor rods are perpendicular to the straight top plate, and a row of anchor rods close to the curved top plate is inclined toward the curved top plate. The two rows of anchor cables of the arc-shaped top plate are evenly distributed on the arc-shaped top plate and inclined toward the straight top plate; the three rows of anchor rods of the arc-shaped top plate are evenly distributed on the arc-shaped top plate, and the anchor rods are perpendicular to the arc tangent of the arc-shaped top plate; The two rows of anchor cables on the upper side of the tunnel are evenly distributed on the upper side of the tunnel, and the anchor cables close to the tunnel bottom plate are inclined toward the tunnel bottom plate; the anchor cables close to the tunnel top plate are inclined toward the tunnel top plate; the three rows of anchor rods on the upper side of the tunnel are evenly distributed on the upper side of the tunnel at equal intervals, and the middle anchor rod is perpendicular to the upper side of the tunnel; the anchor rods close to the tunnel bottom plate are inclined toward the tunnel bottom plate; the anchor rods close to the tunnel top plate are inclined toward the tunnel top plate; The two rows of anchor rods on the lower wall of the tunnel are evenly distributed on the lower wall of the tunnel; the anchor rods close to the tunnel bottom plate are inclined toward the tunnel bottom plate; the anchor rods close to the tunnel top plate are inclined toward the tunnel top plate; A virtual connecting line is drawn between the two end points of the arc passing through the arc-shaped roof, and the virtual connecting line forms an angle with the upper wall of the tunnel. The anchor rod at the connection between the tunnel roof and the upper wall of the tunnel is driven into the rock mass along the direction of the bisector of the angle.

3. The coal mining tunnel support facility according to claim 1, characterized in that: The anchor net is laid from the connection between the tunnel upper wall and the tunnel roof, covers the curved roof, and then extends to the tail end of a row of anchor rods in the straight roof close to the curved roof; The anchor net is hung at the tail end of each anchor rod\anchor cable.

4. The coal mining tunnel support facility according to claim 1, characterized in that: Draw hooks are arranged at both ends of the steel bar, and a square tray is hung at the tail end of the anchor rod or anchor cable. The tray is a flat plate perpendicular to the anchor cable and the anchor rod, and a number of columns are arranged vertically upward at the four corners of the tray; the upper end of the column is a cone tip that penetrates into the rock mass; the draw hook is overlapped on the column; A reinforcing rib is arranged between two adjacent and parallel steel bars; the reinforcing rib is composed of connecting hooks at both ends and a connector connecting the connecting hooks at both ends; the front end of the connecting hook is a hook, the rear end is a screw rod, the connector is an internal thread sleeve, and the left and right ends of the internal thread sleeve are respectively provided with a left-hand thread and a right-hand thread.

5. The coal mining tunnel support facility according to claim 1, characterized in that: The arched top beam is composed of a right section of the arch beam near one end of the straight top plate and a left section of the arch beam near one end of the upper wall of the tunnel; A plurality of anchor rod / anchor cable hanging holes are arranged on the arched top beam, which are used to fix the arched top beam to the tail ends of the anchor rods / anchor cables at corresponding locations.

6. The coal mining tunnel support facility according to claim 1, characterized in that: An adhesive layer is arranged around the arch beam sleeve to bond the arch beam sleeve to the sleeve embedding hole.

7. A method for constructing a coal mining tunnel support facility, characterized in that: The specific steps for constructing the coal mining tunnel support facility described in any one of claims 1 to 6 are as follows: (1) After the tunnel is excavated, the exposed rock mass on the top of the tunnel is temporarily supported; then anchor rods and anchor cable holes are driven into the curved roof; (2) A sleeve embedding hole is punched into the straight roof near the intersection of the curved roof and the straight roof, and then an anchor cable hole is punched from the bottom of the sleeve embedding hole toward the old roof; (3) Anchor rods and anchor cables are arranged in the anchor rod / anchor cable holes driven in step (1), and anchor cables are arranged in the anchor cable holes driven in step (2); an anchor net is hung at the tail end of the anchor rod / anchor cable of the curved top plate; (4) Apply cement release agent to the tail end of the anchor cable in the sleeve embedding hole, set the arch beam sleeve in the sleeve embedding hole, and pull the tail end onto the fixed surface for pre-tightening; (5) Pour concrete into the sleeve embedding hole to fix the arch beam sleeve; (6) Anchor rods and anchor cables are installed on the flat roof; (7) Hang a reinforcing net at the end of the anchor rod or anchor cable on the straight top plate; (8) Install an arched beam below the anchor net at the curved top plate; (9) Anchor rod and anchor cable holes are driven into the upper and lower sides of the tunnel, and anchor rods and anchor cables are set in the holes and fixed by grouting.

8. The method for constructing coal mining tunnel support facilities according to claim 7, characterized in that: (1) The sleeve embedding hole is specifically: a sleeve embedding hole having a hole diameter equal to the diameter of the circumscribed circle of the arch beam sleeve and a depth greater than the length of the arch beam sleeve is driven into the flat top plate in a direction perpendicular to the flat top plate; (2) Punching the anchor cable hole from the bottom of the sleeve embedded hole to the old top, specifically: first, a lower notch with a width greater than the diameter of the anchor cable hole drill rod is opened at the lower edge of the hole opening of the sleeve embedded hole, and then the anchor cable hole drill rod is passed through the lower notch and pushed into the bottom of the sleeve embedded hole, and the anchor cable hole is punched to the old top at an angle inclined toward the arc-shaped top plate; (3) Pull the tail end of the anchor cable embedded in the hole of the sleeve onto the fixed surface for pre-tightening. The specific pre-tightening force is 20-40KN. (4) The concrete is poured into the sleeve embedding hole to fix the arch beam sleeve. The specific steps are as follows: a. Inject concrete into the gap between the fixing surface and the bottom of the sleeve embedding hole; inject concrete into the gap between the sleeve embedding hole and the outer surface of the arch beam sleeve; b. 30 minutes after the concrete is injected, the preload sleeve is embedded in the anchor cable in the hole to make the preload force 40-70KN; c. 3 hours after concrete injection, pre-tighten the anchor cable again so that the pre-tightening force is above 150KN.

9. The method for constructing coal mining tunnel support facilities according to claim 7, characterized in that: A reinforcement net is hung at the end of the anchor rod or anchor cable of the straight top plate, specifically: a. Put the pallet into the end of the anchor rod / anchor cable, and hang the hook of the steel bar on the pallet column; b. After the entire flat top plate is equipped with steel bars, pre-tighten each pallet to a pre-tightening force of 20-40KN for the first time; c. Pre-tighten each pallet for the second time until the pre-tightening force is not less than 150KN, until the pallet column is inserted into the rock mass; d. Install reinforcing bars between the loose steel bars and the adjacent and parallel steel bars, and tighten the reinforcing bars.

10. The method for constructing coal mining tunnel support facilities according to claim 7, characterized in that: Install the arched beam below the anchor net at the curved top plate, specifically: a. Insert the end of the right section of the arch beam into the arch beam sleeve to the bottom of the arch beam sleeve, and hang the hanging hole of the right section of the arch beam into the corresponding anchor rod\anchor cable tail end and initially insert the nut; b. Then hinge the left section of the arch beam with the right section of the arch beam, and hang the hanging hole of the left section of the arch beam into the corresponding anchor rod\anchor cable tail end and initially insert the nut; c. Pre-tighten the nuts at the tail end of the anchor rod and anchor cable from the right section of the arch beam to a pre-tightening force of 40-70KN; d. Start again from the right section of the pre-tightened arch beam to the left section of the arch beam and tighten the nuts at the tail end of the anchor rod and anchor cable to a pre-tightening force of more than 150KN.

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