Composite support structure for coal mine roadway and construction method

Abstract

The present application relates to the technical field of coal mine roadway supporting and discloses a coal mine roadway composite supporting structure and a construction method, the coal mine roadway composite supporting structure comprising an anchor net cable spray primary support layer, a mine I-beam framework and a reinforced concrete structure layer, the anchor net cable spray primary support layer being attached to the roadway roof rock wall, the mine I-beam framework being arranged on the outer side of the anchor net cable spray primary support layer, the mine I-beam framework comprising a plurality of I-beams and transverse steel bars connected between adjacent I-beams, the end of each I-beam being provided with a pressure bearing steel plate, the reinforced concrete structure layer being wrapped on the outer side of the mine I-beam framework and forming a cooperative bearing system with the anchor net cable spray primary support layer and the mine I-beam framework. Through the cooperative work of the flexible primary support, the rigid framework and the overall arch shell, the present application realizes a bearing system with rigidity and flexibility, has high bearing capacity and strong structural integrity, and can be applied to the supporting scene of the Y-shaped intersection point of the super-large span roof of the extra-thick impact pressure coal seam.

Description

Technical Field

[0001] This invention belongs to the field of coal mine roadway support technology, specifically relating to a composite support structure and construction method for coal mine roadways. Background Technology

[0002] Y-shaped intersections in coal mine roadways, especially ultra-large span intersections in scenarios involving extra-thick rockburst coal seams, present significantly greater support challenges than ordinary roadway sections due to their large cross-sectional spans, small intersection angles, and complex stress environments.

[0003] In the related technologies, the anchor-mesh-cable-sprayed combined support method uses a flexible anchor-mesh-cable-sprayed layer, which is difficult to withstand the vertical pressure and impact load of ultra-large span roof slabs. The mining H-beams are only used as temporary supports and do not form a cooperative load-bearing system with the anchor-mesh-cable-sprayed layer and concrete layer. The overall structure is poor, stress concentration is prominent, and it is prone to roof slab delamination, spray layer cracking and other defects, which seriously affect the load-bearing capacity and durability of the support structure. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a composite support structure and construction method for coal mine roadways. This composite support structure has high bearing capacity and strong structural integrity, and is suitable for supporting ultra-large span roofs at Y-shaped intersections of extra-thick coal seams prone to rock bursts.

[0005] The embodiments of the present invention also propose a construction method for a composite support structure for coal mine roadways.

[0006] According to an embodiment of the present invention, a composite support structure for coal mine roadways includes an anchor-mesh-shotcrete initial support layer, a mining H-beam frame, and a reinforced concrete structural layer. The anchor-mesh-shotcrete initial support layer is attached to the roof rock wall of the roadway. The mining H-beam frame is located on the outside of the anchor-mesh-shotcrete initial support layer. The mining H-beam frame includes multiple H-beams and transverse reinforcing bars connecting adjacent H-beams. Each H-beam has a bearing steel plate at its end. The reinforced concrete structural layer wraps around the outside of the mining H-beam frame, and the reinforced concrete structural layer, the anchor-mesh-shotcrete initial support layer, and the mining H-beam frame form a cooperative load-bearing system.

[0007] According to an embodiment of the present invention, the coal mine roadway composite support structure forms a three-layer collaborative load-bearing system through an initial support layer of anchor mesh and cable spraying, a mining H-beam frame, and a reinforced concrete structural layer. The initial support layer of anchor mesh and cable spraying quickly seals the surrounding rock and suppresses early deformation. The mining H-beam frame provides bending stiffness and forms a spatial grid structure through transverse reinforcement. The reinforced concrete structural layer wraps the mining H-beam frame to form an integral arch shell as the main load-bearing layer, thus realizing the organic combination of flexible support and rigid support.

[0008] In some embodiments, the pressure-bearing steel plate is welded to the end of the I-beam, and the area of ​​the pressure-bearing steel plate is larger than the cross-sectional area of ​​the end of the I-beam.

[0009] In some embodiments, the transverse reinforcing bars are arranged at intervals along the length of the I-beams, and the transverse reinforcing bars are tied and fixed to each of the I-beams so that multiple I-beams are connected to form a spatial grid structure.

[0010] In some embodiments, the anchor-mesh-cable-shotcrete initial support layer includes anchor bolts, reinforcing mesh, anchor cables, and a shotcrete layer. The reinforcing mesh is laid on the outside of the anchor bolts and anchor cables, and the shotcrete layer covers the reinforcing mesh and the exposed portions of the anchor bolts and anchor cables.

[0011] In some embodiments, the reinforced concrete structural layer includes a foundation paving bottom and an arch shell, the arch shell completely enclosing the mining I-beam frame and the pressure-bearing steel plate.

[0012] In some embodiments, an additional reinforcing mesh is provided within the reinforced concrete structural layer, and the additional reinforcing mesh is connected to the transverse reinforcing bars of the mining I-beam frame.

[0013] According to an embodiment of the present invention, a construction method for a composite support structure for coal mine roadways includes a primary support layer of anchor mesh and shotcrete as described above, a mining H-beam frame, and a reinforced concrete structural layer. The construction method includes: constructing the primary support layer of anchor mesh and shotcrete after roadway excavation; erecting the mining H-beam frame on the outside of the primary support layer of anchor mesh and shotcrete, the mining H-beam frame including multiple H-beams and transverse reinforcing bars connecting adjacent H-beams, with a bearing steel plate welded to the end of each H-beam; setting up a formwork on the outside of the mining H-beam frame and pouring concrete to form the reinforced concrete structural layer enclosing the mining H-beam frame.

[0014] The construction method of the composite support structure for coal mine roadways according to the embodiments of the present invention follows the principles of flexible construction first, rigid construction later, layered construction, and coordinated molding. The construction process is highly standardized, which can effectively shorten the construction cycle and improve the molding quality.

[0015] In some embodiments, constructing the anchor mesh and shotcrete initial support layer includes: drilling holes and installing anchor bolts and anchor cables; laying a steel mesh and fixing it to the anchor bolts and anchor cables; and shotcreting concrete to cover the steel mesh and the exposed portions of the anchor bolts and anchor cables.

[0016] In some embodiments, the construction method further includes: excavating a foundation trench along the bottom slab of the roadway and pouring a concrete cushion layer before erecting the mining I-beam frame.

[0017] In some embodiments, the reinforced concrete structural layer is poured in sequence from the bottom of the foundation to the arch shell. Attached Figure Description

[0018] Figure 1 This is an overall schematic diagram of the present invention.

[0019] Figure 2 This is a top view schematic diagram of the mining I-beam frame in this invention.

[0020] Figure 3 This is a top view of the pressure-bearing steel plate in this invention.

[0021] Figure label: 100. Composite support structure for coal mine roadways; 1. Anchor mesh and shotcrete initial support layer; 11. Anchor bolts; 12. Shotcrete layer; 13. Anchor cables; 2. Mining I-beam frame; 21. I-beam; 22. Transverse reinforcement; 23. Bearing steel plate; 200. The roof and rock walls of the tunnel. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] like Figures 1 to 3 As shown, the coal mine roadway composite support structure 100 according to an embodiment of the present invention includes an anchor-mesh-and-sprayed initial support layer 1, a mining H-beam frame 2, and a reinforced concrete structural layer. The anchor-mesh-and-sprayed initial support layer 1 is attached to the roadway roof rock wall 200, the mining H-beam frame 2 is located on the outside of the anchor-mesh-and-sprayed initial support layer 1, and the reinforced concrete structural layer wraps around the outside of the mining H-beam frame 2. These three layers are arranged sequentially from the inside out. The anchor-mesh-and-sprayed initial support layer 1 serves as a flexible initial support layer, quickly sealing the surrounding rock and suppressing early deformation; the mining H-beam frame 2 serves as a rigid frame layer, providing bending stiffness and forming a spatial stress grid; the reinforced concrete structural layer serves as an integral arch shell layer, wrapping the mining H-beam frame 2 to form the main load-bearing structure. The three layers work together to form a synergistic load-bearing system that combines rigidity and flexibility, which can improve the problems of insufficient load-bearing capacity of anchor-mesh-and-sprayed support and lack of synergy between the mining H-beam and the concrete layer in related technologies.

[0024] It should be noted that the coal mine roadway composite support structure 100 of the present invention is applicable to various roadway intersection forms, such as Y-shaped intersections, cross-shaped intersections, etc., and is especially suitable for ultra-large span intersection support with a span greater than 10m in the case of extra-thick rockburst coal seams.

[0025] According to an embodiment of the present invention, the coal mine roadway composite support structure 100 includes a mining H-beam frame 2 comprising multiple H-beams 21 and transverse reinforcing bars 22 connecting adjacent H-beams 21, and each H-beam 21 is provided with a bearing steel plate 23 at its end.

[0026] Specifically, the I-beams 21 can be made of No. 11 mining I-beams, with the length of a single beam determined based on the span of the roof profile at the intersection point. The I-beams 21 are machined to an arc shape according to the Y-shaped intersection point roof profile. The arc of the machined I-beams 21 matches the outer surface of the anchor-mesh-shotcrete initial support layer 1, with a fit gap not exceeding 30mm, ensuring tight contact between the I-beams 21 and the anchor-mesh-shotcrete initial support layer 1 and preventing stress transmission interruption due to excessive gaps. Multiple I-beams 21 are evenly arranged along the roof profile, with an adjacent spacing of 0.8m. For an intersection point with a span of 13.97m, 30 I-beams 21 can be installed, with bearing steel plates 23 at both the top and bottom ends of each I-beam 21.

[0027] In some embodiments, the pressure-bearing steel plate 23 is welded to the end of the I-beam 21, and the area of ​​the pressure-bearing steel plate 23 is larger than the cross-sectional area of ​​the end of the I-beam 21. The pressure-bearing steel plate 23 can be a 300mm×300mm×10mm Q235B square steel plate, welded to the upper and lower ends of the I-beam 21 using a double-sided full welding method, with a weld height of not less than 8mm. Before welding, rust and oil stains on the end of the I-beam 21 and the surface of the pressure-bearing steel plate 23 must be cleaned to avoid welding defects such as incomplete welding or missed welding.

[0028] By setting a bearing steel plate 23 with an area larger than the cross-sectional area of ​​the end of the I-beam 21, the contact area between the end of the I-beam 21 and the reinforced concrete structural layer is increased. This allows the concentrated load transmitted by the I-beam 21 to be distributed to a larger area of ​​concrete through the bearing steel plate 23, reducing local compressive stress at the contact surface and lowering the risk of local crushing or cracking of the concrete due to stress concentration. Simultaneously, after being embedded within the reinforced concrete structural layer, the bearing steel plate 23 also acts as a shear connector, enhancing the interfacial shear resistance between the I-beam frame 2 and the concrete structural layer 3, thus improving their collaborative performance.

[0029] In some embodiments, the transverse reinforcing bars 22 are arranged at intervals along the length of the I-beams 21, and are tied to each I-beam 21 to form a spatial grid structure. Specifically, the transverse reinforcing bars 22 can be made of 16# threaded steel and are evenly arranged at 300mm intervals along the length of the I-beams 21. The intersections of the transverse reinforcing bars 22 and each I-beam 21 are fixed using a figure-eight binding method, with double-strand binding wire wrapped around the binding points at least 3 times to ensure a firm binding and prevent relative displacement between the transverse reinforcing bars 22 and the I-beams 21.

[0030] Multiple independently arranged I-beams 21 are connected into an overall spatial grid structure by transverse reinforcing bars 22, transforming the originally independent I-beams 21 into a unified load-bearing system. When the top plate load acts on a certain area, the load is transferred to adjacent I-beams 21 through the transverse reinforcing bars 22, realizing the lateral distribution and diffusion of the load, which helps to prevent buckling instability of a single I-beam 21 due to local overload. At the same time, the spatial grid structure can improve the overall torsional stiffness and out-of-plane stability of the mining I-beam frame 2, enabling it to maintain good structural stability when subjected to eccentric loads or impact loads.

[0031] In some embodiments, the anchor-mesh-cable-shotcrete initial support layer 1 includes anchor bolts 11, steel mesh, anchor cables 13, and shotcrete layer 12. The steel mesh is laid on the outside of the anchor bolts 11 and anchor cables 13, and the shotcrete layer 12 covers the exposed portions of the steel mesh, anchor bolts 11, and anchor cables 13.

[0032] Specifically, anchor bolt 11 can be a high-strength threaded steel anchor bolt with a specification of Φ22×2800mm, arranged in a staggered pattern with a row spacing of 800mm×800mm. The tail of anchor bolt 11 is equipped with a 150mm×150mm×10mm butterfly tray and nut, and is anchored using resin anchoring agent with a mixing time of not less than 30 seconds. After installation, a pre-tightening force of not less than 100kN is applied to ensure a tight fit between anchor bolt 11 and the surrounding rock, providing initial anchoring force. Anchor cable 13 can be a high-strength, low-relaxation steel strand anchor cable with a specification of Φ17.8×6300mm, arranged in rows with a row spacing of 1600mm×1600mm, with an anchoring depth of not less than 4.5m. The tail is fixed with an anchor, and a pre-tightening force of not less than 250kN is applied. It is used for deep reinforcement of the roof rock mass and dispersion of concentrated stress. When laying the reinforcing mesh, it should fit tightly against the anchor bolt tray, with an overlap length of not less than 100mm between adjacent mesh sections. The overlap should be secured with binding wire every 200mm. The shotcrete layer 12 uses C20 grade shotcrete with a thickness of 100mm, a spraying distance of 0.8-1.2m, and an angle of not less than 70° with the rock wall. It should ensure that the exposed parts of the reinforcing mesh, anchor bolts 11, and anchor cables 13 are covered, and the surface flatness error after spraying should not exceed 50mm.

[0033] The anchor-mesh-cable-shotcrete initial support layer 1, as the innermost layer of the composite support system, works on the following principle: after tunnel excavation, the stress in the surrounding rock redistributes, and the roof rock mass tends to deform towards the free face. Anchor bolts 11 and anchor cables 13, through pre-tensioning, actively restrain delamination and slippage in the shallow and deep parts of the roof rock mass, forming a compression zone within the roof rock mass. The steel mesh, laid on the outside of the anchor bolts 11 and anchor cables 13, acts as a support, preventing broken rock fragments from falling. The shotcrete layer 12 quickly covers the rock wall surface, sealing the surrounding rock, isolating it from air, inhibiting rock weathering, and forming an integrated stress point with the anchor bolts 11 and anchor cables 13. The function of the anchor-mesh-cable-shotcrete initial support layer 1 is to quickly seal the surrounding rock, inhibit early deformation, and provide a safe working environment for the subsequent construction of the mining I-beam frame 2 and reinforced concrete structural layers.

[0034] In some embodiments, a reinforced concrete structural layer is wrapped around the outside of the mining H-beam frame 2. The reinforced concrete structural layer includes a foundation base and an arch shell. The thickness of the foundation base is not less than 600 mm, and the arch shell completely wraps around the mining H-beam frame 2 and the bearing steel plate 23. An additional steel mesh is provided inside the reinforced concrete structural layer, and the additional steel mesh is connected to the transverse steel bars 22 of the mining H-beam frame 2.

[0035] Specifically, the reinforced concrete structural layer uses C30 grade commercial concrete with a standard value of not less than 20.1 MPa for axial compressive strength and not less than 3.0 × 10⁴ MPa for elastic modulus. The thickness of the foundation bottom layer is not less than 600 mm, and the thickness of the sidewalls is adjusted according to the span of the top slab. For the intersection point with a span of 13.97 m, the sidewall thickness is 500 mm, completely enclosing the mining H-beam frame 2 and the bearing steel plate 23. The radius of curvature of the arch shell is optimized according to the included angle and span of the Y-shaped intersection point to make the stress distribution more uniform and reduce stress concentration caused by local curvature abrupt changes. The additional reinforcing mesh can use Φ12mm@200×200mm load-bearing reinforcing mesh, which is tied to the transverse reinforcing bars 22 of the mining H-beam frame 2 to form a unified reinforcing mesh system.

[0036] The reinforced concrete structural layer, the mining H-beam frame 2, and the anchor-mesh-sprayed initial support layer 1 form a collaborative load-bearing system. Its working principle is as follows: The reinforced concrete structural layer, as the outermost integral arch shell, is the main load-bearing layer of the composite support system. The arch shell structure transforms the vertical load transmitted from the top slab into compressive stress along the tangent direction of the arch shell, fully utilizing the high compressive strength of concrete. The mining H-beam frame 2 is embedded in the arch shell, sharing the load with the concrete. The high bending stiffness of the H-beam 21 compensates for the relatively low tensile strength of the concrete. The bearing steel plate 23 increases the contact area between the ends of the H-beam 21 and the concrete, facilitating uniform load distribution. The transverse reinforcing bars 22 connect multiple H-beams 21 into a spatial grid and are tied to the additional reinforcing mesh, forming a double reinforcing system. This effectively inhibits the propagation of concrete cracks and improves the structure's crack resistance and ductility. The enlarged foundation at the bottom disperses the upper load to a wider area of ​​the bottom rock mass, reducing the compressive stress at the base and helping to reduce uneven settlement caused by reliance on the original rock mass for bearing.

[0037] The coal mine roadway composite support structure 100 according to an embodiment of the present invention achieves an organic combination of flexible and rigid support through the flexible pressure relief and rapid closure function of the anchor-mesh-cable-sprayed initial support layer 1, the rigid bending resistance and spatial grid effect of the mining I-beam frame 2, and the overall arch shell and enlarged foundation of the reinforced concrete structural layer, with the three layers working together to bear the load. Compared with the anchor-mesh-cable-sprayed combined support in related technologies, the roof bearing capacity can be significantly improved, and the roof delamination can be significantly reduced; the enlarged foundation can effectively reduce uneven settlement; and the stress concentration coefficient in the core area of ​​the Y-shaped intersection point is reduced, which can improve defects such as roof delamination, spalling, and cracking of the sprayed layer.

[0038] According to an embodiment of the present invention, the construction method of a composite support structure for coal mine roadways, wherein the composite support structure 100 comprises an anchor-mesh-cable-spray initial support layer 1, a mining I-beam frame 2, and a reinforced concrete structural layer, and the construction method includes the following steps: After the tunnel excavation is completed, the initial support layer 1 (anchor mesh and shotcrete) is constructed. Specifically, the excavation is carried out using smooth blasting technology according to the Y-shaped intersection design cross-section, controlling the height of the 200mm protrusion of the roof rock wall after blasting to be no more than 100mm and the depth of the depression to be no more than 150mm. The construction of the initial support layer 1 (anchor mesh and shotcrete) includes: drilling and installing anchor bolts 11 and anchor cables 13; laying a steel mesh and fixing it to the anchor bolts 11 and anchor cables 13; and spraying concrete to cover the steel mesh and the exposed parts of the anchor bolts 11 and anchor cables 13.

[0039] Furthermore, the borehole diameter for anchor bolt 11 is 28mm, and the depth is 50mm greater than the anchor bolt length; the borehole diameter for anchor cable 13 is Φ32mm, and the depth is 100mm greater than the anchor cable length. After drilling, the rock powder inside the hole is cleaned, and anchor bolt 11 is anchored using resin anchoring agent. The mixing time is not less than 30 seconds, and a preload of not less than 100kN is applied after installation. Anchor cable 13 is anchored along its entire length using resin anchoring agent, and a preload of not less than 250kN is applied after installation. When laying the reinforcing mesh, it should fit tightly against the anchor bolt tray, with an overlap length of not less than 100mm between adjacent mesh sections. Shotcrete of grade C20 is used, applied in sections, with a spraying distance of 0.8-1.2m, an angle of not less than 70° with the rock wall, a spray thickness of 100mm, and a curing time of not less than 72 hours.

[0040] The construction of the initial support layer 1 of the anchor mesh and cable spraying can quickly seal the surrounding rock of the top plate, inhibit early deformation of the rock mass, and provide a safe working surface for subsequent processes. This reflects the principle of "flexible first, rigid later, layered construction, and coordinated forming" of the construction method of this invention.

[0041] In some embodiments, before erecting the mining I-beam frame 2, a foundation trench is excavated along the roadway floor and a concrete cushion layer is poured. Specifically, the foundation trench is excavated along the designed location on the roadway floor, with a width 200mm greater than the width of the foundation slab bottom and a depth 100mm greater than the thickness of the foundation slab bottom. The bottom of the trench is manually leveled, with a flatness error not exceeding 20mm. A 100mm thick C15 concrete cushion layer is then laid and compacted using a plate vibrator, with a surface flatness error not exceeding 30mm. The curing time is not less than 48 hours. The concrete cushion layer provides a flat and solid base for the foundation slab bottom of the subsequent reinforced concrete structural layer, which is beneficial for the uniform transfer of force at the foundation slab bottom.

[0042] A mining H-beam frame 2 is erected on the outside of the initial support layer 1 of the anchor mesh and shotcrete system. No. 11 mining H-beams 21 are pre-fabricated according to the roof outline, ensuring the curvature meets the fitting gap requirements. The H-beams 21 are hoisted to the designed position using lifting equipment, adjusting the verticality error to no more than 3° and the spacing error to no more than 50mm. After positioning, the bearing steel plates 23 are welded to the upper and lower ends of the H-beams 21. Before welding, rust and oil stains are cleaned to avoid incomplete or missed welds. Then, transverse reinforcing bars 22 are laid, arranged at 300mm intervals along the length of the H-beams 21. The intersections of the transverse reinforcing bars 22 and each H-beam 21 are fixed with a figure-eight binding, ensuring a firm and secure binding, so that all the H-beams 21 are connected to form a spatial grid structure.

[0043] Formwork is erected on the outside of the mining I-beam frame 2, and concrete is poured to form a reinforced concrete structural layer enclosing the mining I-beam frame 2. Steel formwork with a thickness of not less than 5mm is used to support the outer formwork. The support system uses 48×3.5mm steel pipe scaffolding, with a vertical pole spacing of not more than 1.2m, a horizontal bar spacing of not more than 1.5m, a verticality error of not more than 5mm / m, a flatness error of not more than 3mm / m, and a joint width of not more than 2mm. Additional steel mesh is laid and tied to the transverse steel bars 22. After the concealed works pass inspection, C30 commercial concrete is poured.

[0044] In some embodiments, the reinforced concrete structural layers are poured sequentially from the bottom of the foundation to the arch shell. During pouring, an immersion vibrator is used for compaction, with an insertion depth of not less than 50mm and a spacing of not more than 300mm. Each vibration point is vibrated for 20-30 seconds to ensure concrete density. After pouring, the surface is smoothed. Within 12 hours of pouring, the concrete is covered with geotextile and watered for curing, with a curing period of not less than 14 days. After curing, the structural dimensions, concrete strength, and appearance quality are inspected and accepted; only after passing inspection can the structure be put into use.

[0045] According to the construction method of this invention, the standardized processing, positioning, and binding procedures reduce manual adjustment time, and the construction cycle can be significantly shortened compared to traditional methods. Standardized formwork erection and concrete pouring operations are beneficial for controlling structural dimensional errors and improving the concrete strength qualification rate, while effectively reducing subsequent maintenance frequency and costs.

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A composite support structure for coal mine roadways, characterized in that, include: An anchor-mesh-shotcrete initial support layer, which is attached to the roof rock wall of the roadway; A mining H-beam frame is provided on the outside of the anchor mesh and shotcrete initial support layer. The mining H-beam frame includes multiple H-beams and transverse reinforcing bars connecting adjacent H-beams. Each H-beam has a bearing steel plate at its end. A reinforced concrete structural layer is provided, which is wrapped around the outside of the mining I-beam frame. The reinforced concrete structural layer, the anchor mesh and shotcrete initial support layer, and the mining I-beam frame together form a load-bearing structure.

2. The composite support structure for coal mine roadways according to claim 1, characterized in that, The pressure-bearing steel plate is disposed at the end of the I-beam, and the area of ​​the pressure-bearing steel plate is larger than the cross-sectional area of ​​the end of the I-beam.

3. The composite support structure for coal mine roadways according to claim 1, characterized in that, The transverse reinforcing bars are arranged at intervals along the length of the I-beams, and the transverse reinforcing bars are fixed to each I-beam so that multiple I-beams are connected to form a spatial grid structure.

4. The composite support structure for coal mine roadways according to claim 1, characterized in that, The initial support layer of the anchor-mesh-cable-shotcrete system includes anchor bolts, steel mesh, anchor cables, and a shotcrete layer. The steel mesh is laid on the outside of the anchor bolts and anchor cables, and the shotcrete layer covers the steel mesh and the exposed portions of the anchor bolts and anchor cables.

5. The composite support structure for coal mine roadways according to claim 1, characterized in that, The reinforced concrete structural layer includes a foundation base and an arch shell, the arch shell of which completely encloses the mining I-beam frame and the pressure-bearing steel plate.

6. The composite support structure for coal mine roadways according to claim 5, characterized in that, An additional steel mesh is provided within the reinforced concrete structural layer, and the additional steel mesh is connected to the transverse steel bars of the mining I-beam frame.

7. A construction method for a composite support structure for coal mine roadways, characterized in that, The coal mine roadway composite support structure comprises, as described in any one of claims 1-6, an anchor-mesh-cable-shotcrete initial support layer, a mining I-beam frame, and a reinforced concrete structural layer; the construction method includes: After the tunnel excavation is completed, the anchor mesh and cable spraying initial support layer is constructed; The mining H-beam frame is erected on the outside of the anchor mesh and shotcrete initial support layer. The mining H-beam frame includes multiple H-beams and transverse reinforcing bars connecting adjacent H-beams. Each H-beam has a pressure-bearing steel plate welded to its end. A template is erected on the outside of the mining I-beam frame, and concrete is poured to form the reinforced concrete structural layer that encloses the mining I-beam frame.

8. The construction method of the composite support structure for coal mine roadways according to claim 7, characterized in that, The construction of the anchor mesh and shotcrete initial support layer includes: Drill holes and install anchor bolts and anchor cables; Lay a steel mesh and fix it to the anchor bolt and the anchor cable; Shotcrete is applied to cover the exposed portions of the steel mesh, anchor bolts, and anchor cables.

9. The construction method of the composite support structure for coal mine roadways according to claim 7, characterized in that, Also includes: Before erecting the mining I-beam frame, foundation trenches are excavated along the bottom slab of the roadway and a concrete cushion layer is poured.

10. The construction method of the composite support structure for coal mine roadways according to claim 7, characterized in that, The concrete structural layer is poured in sequence from the bottom of the foundation to the arch shell.

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