A combined roadway protection device for roadway retention along the goaf.

Abstract

This utility model provides a combined roadway protection device for gob-side roadway retention, comprising: a bolt and cable support device including bolts, cables, and constant-resistance cables placed within the roadway roof; a temporary support device including individual hydraulic props and unit supports; a roadway retaining wall support device including a retaining wall abutting the roadway wall on the gob side, and support piles installed outside the retaining wall; the retaining wall includes a wall body. This utility model provides a simple and easy-to-operate combined roadway protection device particularly suitable for gob-side roadway retention in deep, high-stress roadways. This device can maximize the control of surrounding rock deformation during gob-side roadway retention, reduce roadway maintenance, and thus achieve roadway reuse requirements.

Description

Technical Field

[0001] This utility model belongs to the field of tunnel support technology, specifically relating to a combined tunnel protection device for roadway retention along the goaf. Background Technology

[0002] As coal mining progresses deeper, the resulting large deformation and damage to surrounding rock, as well as severe impact hazards, become increasingly serious. In the complex geomechanical environment of deep mining—characterized by high ground stress, high ground temperature, high osmotic pressure, intense mining activity, and multi-field coupling—the stress characteristics, coal and rock mass failure properties, strata movement, and energy accumulation and release patterns all undergo significant changes. This causes significant damage to the surrounding rock of the roadways, leading to repeated maintenance and substantial losses of manpower, financial resources, and materials. The traditional 121 mining process, which equips one mining face with two return roadways (transport roadway and return airway), results in a significant waste of coal pillar resources. While the 110 method, a pillarless self-contained roadway technology, allows for maximum coal resource extraction, its application still faces severe roadway damage and deformation under complex geological conditions, necessitating repeated repairs.

[0003] To address the above issues, a combined roadway protection device for gob-side roadway retention was invented. In particular, a combined support device was proposed for gob-side roadway retention in deep high-stress roadways, and its construction method was clarified. This device can ensure that the deformation of the surrounding rock is controllable during roadway use, guarantee the stability of the surrounding rock, and monitor the surrounding rock in real time through the device's built-in pressure and displacement monitoring devices, thus ensuring the safety of the roadway.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The present invention addresses the above-mentioned problems by providing a combined roadway protection device for gob-side roadway retention in deep, high-stress roadways that is simple in structure and easy to operate. This device can control the deformation of the surrounding rock of the gob-side roadway retention to the greatest extent, reduce roadway maintenance, and thus achieve the requirements for roadway reuse.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] An improvement of a combined roadway protection device for gob-side roadway retention is that the combined roadway protection device comprises:

[0008] Anchor bolt and cable support devices are added along the roadway axis; including anchor bolts, anchor cables, and constant resistance anchor cables placed in the roadway roof.

[0009] Temporary support devices are added along the axial direction of the roadway; including individual hydraulic props 22 and unit supports 23 placed inside the roadway.

[0010] A roadway retaining wall support device is added along the roadway axis; it includes a retaining wall that is attached to the roadway retaining wall on one side of the goaf, and support piles installed outside the retaining wall; the retaining wall includes a wall body 20.

[0011] Preferably, the wall 20 includes: a plurality of wall units 1, which are spliced ​​together to form the wall 20.

[0012] Preferably, the wall unit includes: a box, which is a hollow metal box; and grouting holes 24 are provided on the surface of the box facing the tunnel.

[0013] The first end of the box is provided with a protrusion 4; the second end of the box is provided with a slot 2 that matches the protrusion; adjacent wall units are connected by the protrusion and the slot.

[0014] The top surface of the enclosure is provided with a top surface protrusion 3, and the bottom surface of the enclosure is provided with a bottom surface groove that matches the top surface protrusion 3; adjacent wall units are connected by the top surface protrusion 3 and the bottom surface groove.

[0015] Preferably, the bottom wall unit 5 located at the bottom of the wall also includes: wall unit reinforcing ribs 6 and support plates;

[0016] Support plates are provided on both sides of the bottom of the bottom wall unit; three right-angled triangular plates perpendicular to the side of the wall unit are evenly provided on the support plate placed on one side of the bottom wall unit as wall unit reinforcing ribs 6.

[0017] The bottom wall unit with reinforcing ribs is attached to the side of the tunnel wall.

[0018] Preferably, the support pile includes: a steel pipe concrete support column 12 and a hydraulic support column 13 connected coaxially;

[0019] The steel-concrete composite support 12 includes multiple coaxially arranged steel-concrete composite sleeves 7; the steel-concrete composite sleeves 7 are hollow tubular objects with through holes on their side walls as grouting holes 10 for the support.

[0020] Preferably, adjacent support piles are connected by a connector; the connector includes a connecting rod 14 and a fixing ring 15 connected to both ends of the connecting rod 14; the fixing ring 15 is a ring-shaped object that is sleeved on the support pile.

[0021] Preferably, a roadway top grouting pipe 28-1 is installed in the roadway roof near the cut side, and a goaf grouting pipe 28-2 is also installed in the goaf area.

[0022] Preferably, a layer of steel mesh with flame-retardant tarpaulin is laid on the surface of the retaining wall; the flame-retardant tarpaulin is attached to the wall 20; and a polymer material is sprayed on the outside of the steel mesh for sealing treatment.

[0023] Beneficial effects:

[0024] 1. By using retaining walls, the risk of gangue entering the tunnel due to the impact of retaining walls can be greatly reduced;

[0025] 2. Grouting in the goaf can increase the density of the goaf, reduce the amount of rotational deformation of the roadway roof, and reduce the risk of spontaneous combustion of gas.

[0026] 3. The use of anchor bolts, anchor cables, and constant resistance anchor cables for combined support of the roadway roof can apply high preload to the roof while also providing some pressure relief, ensuring that the roof can be anchored in stable rock strata by NPR anchor cables.

[0027] 4. The combined roadway protection device for roadway retention involved in this application has a simple structure and a clear construction method. The combined support structure has a high pressure-bearing capacity and deformation resistance. At the same time, the construction process is simple and can effectively improve the roadway retention support effect, control the deformation of the surrounding rock, and achieve the purpose of roadway protection. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. Wherein:

[0029] Figure 1 This is a schematic diagram of the roadway cross-section of the combined roadway protection device involved in this application;

[0030] Figure 2 This is a top view of the roadway involved in the combined roadway protection device described in this application;

[0031] Figure 3 This is one of the schematic diagrams of the retaining wall structure involved in this application;

[0032] Figure 4 This is the second schematic diagram of the retaining wall structure involved in this application;

[0033] Figure 5 This is a schematic diagram of the wall unit structure involved in this application;

[0034] Figure 6 This is a schematic diagram of the bottom wall unit structure involved in this application;

[0035] Figure 7 This is a schematic diagram of the wall unit connection involved in this application;

[0036] Figure 8This is a schematic diagram of the connection of the bottom wall unit involved in this application;

[0037] Figure 9 This is a schematic diagram of the steel-concrete composite sleeve structure involved in this application;

[0038] Figure 10 This application involves a schematic diagram of the support piles;

[0039] Figure 11 This is a schematic diagram of the linkage structure involved in this application;

[0040] The components are as follows: 1. Wall unit; 2. Slot; 3. Top protrusion; 4. Protrusion; 5. Bottom wall unit; 6. Wall unit reinforcing rib; 7. Steel pipe concrete sleeve; 8. Sleeve reinforcing rib; 9. High-strength bolt; 10. Support grouting hole; 11-1. Upper base; 11-2. Lower base; 12. Steel pipe concrete support; 13. Hydraulic support; 14. Connecting rod; 15. Fixing ring; 16. Goaf; 17. Working face; 18. Roadway; 19. Grouting pump; 20. Wall; 21. Crossbeam; 22. Single hydraulic support; 23. Unit support; 24. Grouting hole; 25. Anchor bolt; 26. Anchor cable; 27. Constant resistance anchor cable; 28-1. Roadway top grouting pipe; 28-2. Goaf grouting pipe; 29. ​​Sealing unit. Detailed Implementation

[0041] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art are within the protection scope of this utility model.

[0042] In the description of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., 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 utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. The terms "connected" and "linked" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0044] like Figure 1 and Figure 2 As shown, a combined roadway protection device for gob-side roadway retention is improved in that the combined roadway protection device includes:

[0045] Anchor bolt and cable support devices are installed radially along the roadway and additionally along the roadway axially; including anchor bolts, anchor cables, and constant resistance anchor cables placed in the roadway roof.

[0046] Temporary support devices are added along the axial direction of the roadway; including individual hydraulic props 22 and unit supports 23 placed inside the roadway and located on both sides of the roadway.

[0047] A roadway retaining wall rock retaining support device is added along the roadway axis; it includes a retaining wall that is attached to the roadway retaining wall on one side of the goaf 16; the retaining wall includes a wall body 20; the roadway retaining wall rock retaining support device also includes support piles set near the outer wall of the wall body 20, that is, support piles are set on the roadway cut side; the support piles include steel pipe concrete props 12 and hydraulic props 13 that are coaxially integrated.

[0048] Specifically, the combined roadway protection device for roadway retention involved in this application includes a bolt and cable support device, which is added along the roadway axis; including bolts 25, cables 26, and constant resistance cables 27 placed in the roadway roof.

[0049] Preferably, constant-resistance anchor cables are arranged on the roadway roof to anchor the shallow surrounding rock into the deep strata, thereby enhancing roadway stability. A roadway top grouting pipe 28-1 is arranged near the cut side. Top grouting forms a complete, integral structure from the shallow, fractured surrounding rock, preventing further breakage. Simultaneously, a goaf grouting pipe 28-2 is also installed in the goaf 16. Its primary function is to spray an inhibitor, which forms a protective film on the coal surface, blocking oxygen contact and preventing spontaneous combustion. After the inhibitor is sprayed, grouting is performed. The main function of grouting is to prevent excessive pressure on the roadway roof when the overlying strata of the goaf are hard, leading to roof rotation and subsequent subsidence on the cut side if the goaf collapses prematurely. Therefore, grouting can enhance the density of the goaf in advance, preventing continuous roof subsidence. The tunnel 18 is also equipped with unit supports 23, single hydraulic props 22, crossbeams 21, grouting pumps 19 and other equipment.

[0050] Specifically, anchor bolts 25, anchor cables 26, and constant-resistance anchor cables 27 are installed within the tunnel roof along both the radial and axial directions of the tunnel. Commonly used anchor bolts 25, anchor cables 26, and constant-resistance anchor cables 27 are sufficient. Among them, anchor bolt 25 is the shortest; anchor cable 26 is the next shortest; and constant-resistance anchor cable 27 is the longest.

[0051] The radial arrangement order of anchor bolts 25, anchor cables 26, and constant-resistance anchor cables 27 is not restricted and can be arranged according to design requirements. In this application, anchor bolts 25 are preferred, and anchor cables 26 are arranged between radially adjacent anchor bolts 25; constant-resistance anchor cables 27 are inserted between anchor cables 26 and anchor bolts 25, more preferably in the middle of the roadway roof and above the support piles.

[0052] like Figure 3 and Figure 4 As shown, the wall 20 constituting the retaining wall includes multiple wall units 1, which are spliced ​​together to form the wall 20.

[0053] Wall unit 1 includes: a box-shaped body, the interior of which is hollow and serves as a filling mold; through holes are provided on the surface of the box-shaped body facing the tunnel, serving as grouting holes 24. The wall unit is 800mm long, 500mm wide, and 800mm high, with a protruding part at the front and a recessed groove at the rear. By fitting the front and rear together, an integral structure is formed. The upper part of the mold has a protrusion, and the bottom has a corresponding recessed groove. By connecting the upper and lower parts, a stable structure is achieved.

[0054] Specifically, such as Figure 5 As shown, the enclosure is made of metal. A protrusion 4 is provided at the first end of the enclosure; a slot 2 matching the protrusion is provided at the second end of the enclosure; adjacent wall units are connected by the protrusion and the slot. Specifically, the shape of the protrusion is not limited; this application uses a T-shaped protrusion, therefore the slot is also correspondingly T-shaped. Figure 7 As shown, the subsequent wall unit engages the T-shaped protrusion into the slot of the previous wall unit, thus completing the connection between adjacent wall units.

[0055] A top protrusion 3 is provided on the top surface of the enclosure, and a bottom groove matching the top protrusion 3 is provided on the bottom surface of the enclosure. Adjacent wall units are engaged via the top protrusion and the bottom groove. Specifically, the shape of the top protrusion is not limited; this application uses a rectangular frame as the top protrusion, and therefore the bottom groove is also correspondingly set as a rectangular frame. The upper wall unit engages its bottom groove with the top protrusion of the lower wall unit, completing the connection between adjacent wall units.

[0056] Preferred, such as Figure 6 As shown, the bottom wall unit 5, located at the very bottom of the wall, also includes: wall unit reinforcing ribs 6 and a support plate. The bottom wall unit has the same dimensions as the wall unit. Reinforcing ribs are located on the left side of the bottom wall unit to prevent impact from gangue, and a support plate is located on the right side to serve as a base for stability after gangue compression. Figure 8 As shown, the connection method of the bottom wall unit is the same as that of the wall unit. The bottom wall unit is only used at the bottom, and through installation, it forms a structure as shown. Figure 3 and Figure 4 The retaining wall shown. The side with the wall unit reinforcing rib 6 is placed on the goaf side. Grouting is performed on each box through grouting holes 24 to support the roof sinking and the lateral pressure of the goaf gangue.

[0057] Specifically, a support plate, made of steel, is installed on the bottom side of the bottom wall unit, with a length corresponding to the length of the bottom wall unit. Support plates are installed on both sides of the bottom of the bottom wall unit. Three right-angled triangular plates, perpendicular to the side of the wall unit, are evenly arranged on the support plate on one side of the bottom wall unit as reinforcing ribs 6. One right-angled side of each triangular plate is fixedly connected to the side of the bottom wall unit, and the other right-angled side is fixedly connected to the support plate. One triangular plate is positioned in the middle of the bottom wall unit, and the other two are positioned on either side of the bottom wall unit.

[0058] The bottom wall unit with the reinforcing rib 6 faces the tunnel wall and is attached to it. First, the bottom wall units are assembled, and then the wall units are built upwards to finally form wall 20.

[0059] Preferably, this application also relates to retaining piles, which are formed by grouting into two steel-concrete composite sleeves 7 constituting the retaining piles to create two steel-concrete composite supports 12 at the bottom of the retaining piles, and the two steel-concrete composite supports 12 are connected by high-strength bolts 9. The total height of the steel-concrete composite supports 12 is 1.5m, and a hydraulic support 13 is installed on the upper part of the steel-concrete composite supports 12 to form the retaining piles. The total height of the retaining piles is 2.5m, with a contraction range of 1m, allowing for appropriate expansion and contraction when the top plate is pressed. Adjacent retaining piles are connected by connecting rods 14 to increase their stability.

[0060] Specifically, the steel-concrete composite support 12 includes multiple coaxially arranged steel-concrete composite sleeves 7. For example... Figure 9 As shown, the steel-concrete composite sleeve 7 is a hollow tubular object with through holes on its side wall serving as grouting holes 10 for the support column. The diameter and number of steel-concrete composite sleeves 7 are determined by the engineering design. In this application, two steel-concrete composite sleeves 7 are overlapped and then connected to the hydraulic support column 13 to form a support pile.

[0061] To facilitate the fixing and connection of the steel-concrete composite sleeve 7, a base 11-1 and a lower base 11-2 are welded to both ends of the steel-concrete composite sleeve 7. Both the upper base 11-1 and the lower base 11-2 include a base plate, which is a sheet-like body with no shape limitation. The area of ​​the base plate is larger than the bottom area of ​​the steel-concrete composite sleeve 7, ensuring that the edge of the base plate can be reserved for setting the sleeve reinforcing ribs. The sleeve reinforcing rib 8 is a right-angled triangular piece, and the material is not limited; metal is acceptable. The two right-angled sides of the sleeve reinforcing rib are welded to the base plate and the side wall of the steel-concrete composite sleeve 7, respectively. The number of sleeve reinforcing ribs is not limited; in this application, four sleeve reinforcing ribs are evenly distributed on the upper base 11-1 and the lower base 11-2. Bolt holes are also provided on the base plate between two sleeve reinforcing ribs. After the upper and lower overlapping steel-concrete composite sleeves 7 are installed with the bolt holes of the base plate aligned, they form a steel-concrete composite support column 12.

[0062] like Figure 10 As shown, the hydraulic prop 13 is coaxially fixedly installed on the upper part of the steel pipe concrete prop 12 to form a support pile. The bottom of the hydraulic prop 13 is also provided with a hydraulic prop base. The structure of the hydraulic prop base is the same as that of the lower base 11-2. During installation, the bolt holes of the hydraulic prop base are aligned with the bolt holes of the upper base 11-1 of the steel pipe concrete sleeve 7 for bolt fixing connection.

[0063] Support piles are added along the axial direction of the roadway. Preferably, adjacent support piles are connected by connectors to increase their stability. Specifically, such as... Figure 11 As shown, the connector includes a connecting rod 14 and retaining rings 15 connected to both ends of the connecting rod 14. The retaining rings 15 are annular and fit onto the steel-concrete composite sleeve 7. The dimensions of the retaining rings 15 match the diameter of the steel-concrete composite sleeve 7. Protrusions are provided on the outer wall of the retaining rings 15 for connection with the connecting rod 14. The connection method is not limited; welding, riveting, etc., are acceptable. The length of the connecting rod 14 matches the spacing of the support piles.

[0064] Preferably, a sealing material is also laid on the surface of the retaining wall. Specifically, a sealing material is also laid on the surface of the wall 20 to form a closed unit 29. Commonly used polymer materials in engineering construction are mainly used for sealing to prevent excessive methane content in the goaf from causing spontaneous combustion.

[0065] Specifically, a layer of steel mesh with flame-retardant tarpaulin is laid on the surface of wall 20. A layer of flame-retardant tarpaulin is then laid inside the steel mesh, adhering to wall 20. The top of the steel mesh is lapped and fixed to the steel reinforcement of the tunnel roof slab, and the bottom of the steel mesh is embedded and fixed with a support plate. During sealing, a polymer material is sprayed onto the outside of the steel mesh for sealing treatment.

[0066] The combined roadway protection device for roadway retention involved in this application also includes a temporary support device, which is added along the roadway axis; including a single hydraulic prop 22 and a unit support 23 placed in the roadway and located on both sides of the roadway.

[0067] Specifically, such as Figure 1 Figure 2 As shown, the unit support 23 includes columnar structures and is installed in the roadway on one side near the goaf area; the individual hydraulic prop 22 is a hydraulic column and is installed on the other side of the roadway, corresponding to the unit support 23. The tops of the unit support 23 and the individual hydraulic prop 22 are connected to the roadway roof through crossbeams 21.

[0068] Specifically, the unit support 23 is a rod-shaped structure with a height corresponding to the height of the roadway. There are no restrictions on the cross-sectional shape of the unit support 23, as long as it can provide support.

[0069] The crossbeam 21 is a rod-shaped structure, preferably made of metal. The width of the crossbeam 21 matches the top diameter of the unit support 23 and the individual hydraulic support 22. The length of the crossbeam 21 is not limited, as long as it is sufficient to connect the unit support 23 and the individual hydraulic support 22.

[0070] This application also provides a construction method for a combined roadway protection device for gob-side roadway retention, comprising the following steps:

[0071] Step S1: Before the 17th working face is mined, the roof of the roadway is supported by anchor bolts and cables, and constant resistance anchor cables are also used for reinforcement support. The support design adopts the traditional "110 method" for construction.

[0072] Step S2 involves grouting the more fractured sections and water-soaked sections of the roadway roof. First, grouting holes are drilled, and a roadway top grouting pipe 28-1 is installed near the cut side, while a goaf grouting pipe 28-2 is installed in goaf 16. The hole depth is determined based on the inspection results. During grouting, the principle of "high pressure fine particles, low pressure coarse particles" is followed. The pressure is set and matched according to the grout particle size and the degree of rock fracture.

[0073] Step S3: Commence face mining. During face mining, retaining walls are installed. The bottom wall units of the retaining walls are positioned close to the goaf. After installation, the retaining walls are grouted. The grout material is selected based on the coal seam depth and thickness. If the coal seam is deep and thick, higher support strength is needed to support the roof pressure and the goaf rock pressure; in this case, concrete can be used as the filling material. If the coal seam is shallow and the pressure is low, high-strength foam can be used as the filling material.

[0074] Step S4: Install support piles on the cut side. The support piles include steel-concrete composite columns, whose main function is to provide continuous support to the tunnel roof. At the same time, the hydraulic props located on top of the support piles can withstand pressure and prevent the steel-concrete composite columns from becoming dead columns. The injection material for the steel pipes can be concrete, sand, etc. If the pressure is high, concrete is selected as permanent support; if the pressure is low, sand is selected as the injection material, which can be reused.

[0075] Step S5 involves arranging temporary support devices within the roadway, including unit supports 23, individual hydraulic props 22, and crossbeams 21, to protect the integrity of the roadway roof. The unit supports 23 primarily support the high-level roof, preventing it from delaminating or rotating. Once the goaf has stabilized, the unit supports 23, individual hydraulic props 22, and crossbeams 21 can be gradually withdrawn, leaving the support piles and retaining walls as supporting structures.

[0076] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be within the scope of protection of the pending claims of the present utility model.

Claims

1. A combined roadway protection device for roadway retention along the goaf, characterized in that, The combined roadway protection device includes: An anchor bolt and cable support device is added along the axial direction of the roadway; the anchor bolt and cable support device includes anchor bolts, anchor cables, and constant resistance anchor cables placed in the roof of the roadway. Temporary support devices are added along the axial direction of the roadway; the temporary support devices include single hydraulic props (22) and unit supports (23) placed in the roadway; A roadway retaining wall rock retaining support device is added along the roadway axis; the roadway retaining wall rock retaining support device includes a rock retaining wall that is attached to the roadway retaining wall on one side of the goaf, and support piles set outside the rock retaining wall; the rock retaining wall includes a wall body (20).

2. The combined roadway protection device for gob-side roadway retention as described in claim 1, characterized in that, The wall (20) includes: multiple wall units (1), which are spliced ​​together to form the wall (20).

3. The combined roadway protection device for gob-side roadway retention as described in claim 2, characterized in that, The wall unit includes: a box, which is a hollow metal box; and grouting holes (24) are provided on the surface of the box facing the tunnel. The first end of the box is provided with a protrusion (4); the second end of the box is provided with a slot (2) that matches the protrusion; the wall units that are adjacent at the beginning and end are connected by the protrusion and the slot. The top surface of the box is provided with a top surface protrusion (3), and the bottom surface of the box is provided with a bottom surface groove that matches the top surface protrusion (3); the upper and lower adjacent wall units are connected by the top surface protrusion (3) and the bottom surface groove.

4. The combined roadway protection device for gob-side roadway retention as described in claim 3, characterized in that, The bottom wall unit (5) located at the bottom of the wall also includes: wall unit reinforcing ribs (6) and support plates; Support plates are provided on both sides of the bottom of the bottom wall unit; three right-angled triangular plates perpendicular to the side of the wall unit are evenly provided on the support plate placed on one side of the bottom wall unit as wall unit reinforcing ribs (6); The bottom wall unit with reinforcing ribs is attached to the side of the tunnel wall.

5. The combined roadway protection device for gob-side roadway retention as described in claim 1, characterized in that, The support piles include: a steel pipe concrete column (12) and a hydraulic column (13) connected coaxially; The steel-concrete composite support (12) includes multiple coaxially arranged steel-concrete composite sleeves (7); the steel-concrete composite sleeves (7) are hollow tubular objects with through holes on their side walls as grouting holes (10) for the support.

6. The combined roadway protection device for gob-side roadway retention as described in claim 1, characterized in that, Adjacent support piles are connected by connectors; the connectors include a connecting rod (14) and a fixing ring (15) connected to both ends of the connecting rod (14); the fixing ring (15) is a ring-shaped object that is fitted onto the support pile.

7. The combined roadway protection device for gob-side roadway retention as described in claim 1, characterized in that, A roadway top grouting pipe (28-1) is installed in the roadway roof near the cut side, and a goaf grouting pipe (28-2) is also installed in the goaf area.

8. The combined roadway protection device for gob-side roadway retention as described in claim 1, characterized in that, A layer of steel mesh with flame-retardant tarpaulin is laid on the surface of the retaining wall; the flame-retardant tarpaulin is attached to the wall (20); and a polymer material is sprayed on the outside of the steel mesh for sealing treatment.

Images