Hydraulic-spring composite energy-absorbing shed frame system for rock burst support under mine

Abstract

The invention discloses a hydraulic-spring composite energy-absorbing shed frame system for an under-mine rock burst support, belongs to the technical field of mine support, and solves the problems of fixed energy-absorbing parameters, low mounting efficiency, poor environmental tolerance and insufficient combined support collaboration of a traditional support. The system comprises a main body supporting structure, a core energy absorption module, a pressure-bearing force transmission structure and a filling layer, and can be combined with a constant-resistance large-deformation anchor rod / anchor cable for use. The main body supporting structure comprises a 36 U-shaped steel arched shed frame and a quick-release yielding clamping cable, so that quick mounting and controllable yielding are realized; the core energy absorption module is composed of a detachable laminated belleville spring set, a replaceable valve element type hydraulic damper and a protective shell, and energy absorption parameters are adjustable. And a support cooperative control unit is further arranged to realize synchronous yielding reset. And the energy absorption of the system is adaptive to 100-500kJ, the installation efficiency is improved by 500%, the service life is prolonged to 2.5 years, and the system is suitable for supporting the multi-grade under-mine rock burst roadway.

Description

Technical Field

[0001] This invention relates to the field of underground mine support technology, specifically to a hydraulic-spring composite energy-absorbing canopy system for underground rockburst support. Background Technology

[0002] Rockbursts are a major disaster in the mining of deep mineral resources. The huge energy released instantaneously can easily cause brittle failure of traditional rigid support systems (such as ordinary U-shaped steel scaffolding), leading to roadway collapse, equipment damage, and casualties.

[0003] Existing support technologies mostly employ "reinforced rigid structures" or "simple retractable connections," which are essentially "passive resistance" and cannot actively dissipate impact energy. They also have significant drawbacks: First, the energy absorption parameters are fixed, only suitable for a single impact level, making it difficult to meet the support needs of different geological conditions such as shallow mining roadways and deep high-stress roadways. Second, installation relies on bolt positioning, which is cumbersome, time-consuming, and inefficient for underground operations. Third, the core energy absorption components are susceptible to erosion from coal dust and water, resulting in short lifespans and high maintenance costs. Fourth, the combined support with constant resistance large deformation anchor bolts / cables lacks coordinated control, making it prone to "local failure first" problems.

[0004] To address the aforementioned shortcomings, there is an urgent need to design a composite support system that is "actively energy-absorbing and adjustable, easy to install, highly adaptable to the environment, and highly collaborative" in order to solve the pain points of traditional technologies. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hydraulic-spring composite energy-absorbing canopy system for rockburst support in mines, which achieves "adjustable energy absorption parameters, improved installation efficiency, enhanced environmental tolerance, and coordinated joint support", transforming passive resistance into active energy absorption and dissipation, and ensuring the support safety of rockburst roadways in mines.

[0006] To address the aforementioned problems, this invention provides a hydraulic-spring composite energy-absorbing canopy system for rockburst support in mines, comprising a main support structure, a core energy-absorbing module, a pressure-bearing and force-transmitting structure, and a filling layer. It can be used in conjunction with constant-resistance, large-deformation anchor bolts / cables to form a synergistic support system. The specific design of each structure is as follows: (I) Main Support Structure The main support structure consists of an arched frame made of high-strength steel and quick-release pressure-relief cable clamps. The high-strength steel is 36U-shaped steel to ensure the rigidity of the foundation support.

[0007] The quick-release pressure-relief cable clamp includes a "mortise and tenon buckle" and a "mine manual hydraulic pretensioner": the mortise and tenon buckle is used for quick positioning and locking of the scaffold components without the need for bolts; the hydraulic pretensioner has a rated pressure of 63MPa, can be operated by a single person, and can achieve rapid pretensioning of the cable clamp.

[0008] The arched scaffold joints are fitted with wear-resistant copper alloy bushings to reduce metal friction loss during scaffold contraction and ensure a smooth pressure relief process. The quick-release pressure relief cable allows the scaffold to contract in a controlled manner when the load exceeds a predetermined value (which can be set to 180-250kN depending on the impact level), thus achieving "secondary pressure relief" protection.

[0009] (II) Core Energy Absorption Module The core energy-absorbing module is fixed to the top beam of the arched scaffold by a mounting base. It is evenly arranged along the length of the top beam with a spacing of 1.2-1.5m and consists of a disc spring assembly, a hydraulic damper, and a protective shell.

[0010] The disc spring assembly adopts a "detachable stacked structure", which includes a base plate (thickness 8mm, stiffness 50kN / mm) and an adjustment plate (thickness 5mm, stiffness gradient 5%-10%). By increasing or decreasing the number of adjustment plates, the total stiffness of the spring can be adjusted from 100-300kN / mm to adapt to different impact energies (100-500kJ).

[0011] The hydraulic damper adopts a "replaceable valve core structure". The valve core is a standard part with a bore diameter of φ2-φ5mm. The damping coefficient can be adjusted from 50-200kN・s / m by replacing the valve core to meet the energy dissipation requirements under different impact loads. The damper oil chamber is reserved with an oil filling port, which can be replenished with mining anti-wear hydraulic oil regularly and is suitable for underground temperatures of -20℃ to 80℃.

[0012] The disc spring assembly and hydraulic damper are connected in parallel or series (selected according to the impact level; parallel connection is selected for moderate impact, and series connection is selected for heavy impact), and are encapsulated together in a protective housing. An overload protection pin is added inside the protective housing: when the impact load exceeds the module's design limit (displacement exceeds the maximum stroke by 200mm), the protection pin shears off, triggering the polyurethane spare buffer pad (20mm thick) inside the housing to prevent overload damage to the spring and damper. The inner wall of the protective housing is coated with a mining lithium-based dustproof lubricating grease layer, and a drain hole (φ5mm diameter) with a one-way valve is opened at the bottom to prevent coal dust intrusion and water accumulation and corrosion.

[0013] (III) Pressure-bearing and force-transmitting structure The pressure transmission structure is a composite structure of "main distribution plate + auxiliary support ribs", including the top plate pressure main distribution plate and the transverse auxiliary support ribs.

[0014] The main distribution plate of the roof pressure is made of Q690 high-strength steel with a thickness of 20mm, covering all core energy-absorbing modules to ensure uniform transmission of roof pressure; the transverse auxiliary support bars are made of Q355 steel with a cross section of 100mm×10mm, and are set every 1.5m along the longitudinal direction below the main distribution plate to prevent the main distribution plate from bending and deforming due to large span (≥5m) roadways.

[0015] The connection between the main distribution plate and the core energy-absorbing module is equipped with 40Cr spherical washers to accommodate slight tilts (≤3°) during scaffold installation, ensuring uniform force distribution on each energy-absorbing module and avoiding localized concentrated loads.

[0016] (iv) Filling layer The filling layer is a "composite functional filler" that is filled between the main pressure distribution plate of the roof and the roof rock wall of the roadway. The structure consists of a polymer dustproof net, a high-strength compressed wood layer, and a mining stainless steel support sheet from top to bottom.

[0017] A polymer dustproof net (0.5mm aperture) is placed on the rock wall side to prevent debris from falling and coal dust from seeping in; a high-strength compressed wood layer (density 0.8g / cm³, compression rate 30%) serves as the main force transmission layer to ensure effective transmission of impact loads; mining stainless steel support plates (thickness 3mm, size 100mm×100mm) are embedded in the compressed wood layer every 1m to improve the filling layer's resistance to long-term collapse (compression amount ≤8%).

[0018] The compressed wood layer is mixed with 10% magnesium hydroxide (a flame retardant for mining) and 2% carbon black (an antistatic agent) during production, which meets the requirements of MT / T113-2019 "Requirements for Flame Retardancy and Antistatic Properties of Polymer Products Used in Coal Mines", thus avoiding the risks of fire and static electricity.

[0019] (v) Collaborative design of joint support The system adds an "intrinsically safe support coordination control unit" that works in conjunction with constant resistance large deformation anchor bolts / cables. The coordination control logic is as follows: when the impact load on the core energy-absorbing module is ≥150kN, the coordination control unit adjusts the locking pressure of the constant resistance anchor bolt through a hydraulic valve, increasing the anchor bolt decompression speed from 5mm / s to 10mm / s, synchronizing with the compression speed of the core energy-absorbing module, thus preventing the anchor bolt from failing first and causing the support frame to overload. The connection method is that the coordination control unit connects the oil chamber of the core energy-absorbing module and the anchor bolt locking device through mining hydraulic pipelines to achieve mechanical transmission of pressure signals (without electronic components).

[0020] Working principle: When a rockburst occurs, the impact load is transmitted sequentially through the tunnel roof rock wall → polymer dustproof netting → composite functional filler → roof pressure main distribution plate to each core energy absorption module: The disc spring assembly is compressed, converting 60%-70% of the impact kinetic energy into elastic potential energy; The piston of the hydraulic damper moves with the compression of the spring, and through the friction of the hydraulic oil in the valve core hole, 20%-30% of the impact kinetic energy is converted into heat energy for dissipation, which prolongs the load application time and reduces the peak force. If the impact load exceeds the design limit of the core energy-absorbing module, the overload protection pin inside the protective shell will shear off, and the spare buffer pad will provide further cushioning. If the impact load continues to increase, the quick-release pressure relief cable of the main support structure triggers "secondary pressure relief", allowing the scaffold to shrink in a controlled manner and preventing overall collapse; After the impact, the hydraulic damper suppresses the rebound oscillation of the disc spring assembly, allowing the system to slowly return to stability; at the same time, the support coordination control unit ensures that the constant resistance anchor bolts and the scaffolding are synchronously reset, maintaining the integrity of the support system. Beneficial effects

[0021] 1. Adjustable energy absorption and wide adaptability: Through the detachable stacked disc spring assembly and replaceable valve core hydraulic damper, the energy absorption parameters (stiffness 100-300kN / mm, damping coefficient 50-200kN·s / m) can be adjusted in stages, making it suitable for roadways with mild (100-200kJ), moderate (200-350kJ), and severe (350-500kJ) rockburst, without the need to replace the entire module, thus reducing equipment costs; 2. Highly efficient installation and easy operation: The quick-release pressure-relief cable clamp, combined with the hydraulic pretensioner, reduces the installation time of the canopy from 15 minutes / unit to 3 minutes / unit, increasing installation efficiency by 500% and reducing the intensity of downhole operations; 3. Environmentally resistant and extended lifespan: The dustproof lubricating grease layer, drainage holes, and flame-retardant and antistatic design of the protective shell enhance the core components' resistance to coal dust and water spray, extending the overall system lifespan from 1.5 years to 2.5 years and reducing maintenance frequency; 4. Collaborative support with high stability: The collaborative support control unit enables synchronous pressure relief and reset of the scaffolding and constant resistance anchors, avoiding local failures and improving overall support stability by 20%. 5. Overload protection, safe and reliable: The system integrates dual overload protection with "backup buffer pad + secondary pressure relief cable clamp", which can prevent system collapse even if the design load is exceeded, and its safety is significantly better than traditional support. Attached Figure Description

[0022] Figure 1: Schematic diagram of the overall system structure (front view), with annotations: 1. Arched frame (36U-shaped steel); 2. Pressure-relief cable clamp; 3. Mounting base; 4. Disc spring assembly; 5. Hydraulic damper; 6. Protective outer shell; 7. Top plate pressure main distribution plate; 8. Composite filling layer (including 81 - polymer dustproof net, 82 - high-strength compressed wood layer, 83 - stainless steel support plate); Figure 2: Schematic diagram of the cross-sectional structure of the core energy absorption module (AA cross-sectional view), with annotations: 4. Disc spring assembly (series / parallel combination); 5. Hydraulic damper; 6. Protective housing; 61. Overload protection pin; 62. Spare buffer pad; 63. Dustproof grease layer; 64. Drain hole; Figure 3: Enlarged view of the pressure-bearing and force-transmitting structure and filling layer (enlarged area B), with annotations: 7. Main pressure distribution plate of the top plate; 71. Transverse auxiliary support ribs; 81. Polymer dustproof netting; 82. High-strength compressed wood layer; 83. Mining stainless steel support sheet; Figure 4: Detailed view of the interface of the main support structure (enlarged area C), annotation: 2. Cable clamping (including tenon and mortise buckles); Figure 5: Schematic diagram of a single disc spring, labeled: 4. Disc spring. Detailed Implementation

[0023] The following, in conjunction with the attached diagram and an application scenario of a mine's 800m deep roadway with moderate rockburst (impact energy 200-350kJ, roadway span 4.5m), illustrates the specific implementation steps of this system: Assembly of main support structure: 36U steel is used to process arched frame (1), and a 5mm thick copper alloy wear-resistant bushing (11) is embedded at the interface of the frame components; the frame components are connected by pressure relief cable (2), and the cable is pre-tightened by a mine manual hydraulic pre-tightener (rated pressure 63MPa), and the pressure relief threshold is set to 220kN to ensure that the axial deviation of the frame after assembly is ≤3mm.

[0024] Core energy absorption module installation: Configuration of core energy absorption module: a disc spring group (4) and a hydraulic damper (5) are connected in parallel. The disc spring group is composed of 8 stacked discs (total stiffness 200kN / mm), and the hydraulic damper is composed of a φ3mm valve core (damping coefficient 120kN・s / m). The spring group and the damper are encapsulated in a stainless steel protective shell (6). Ensure that the overload protection pin (61) is installed in place. The inner wall of the shell is uniformly coated with lithium-based dustproof grease. The core energy absorption module is fixed to the top beam of the scaffold by the mounting base (3). The module spacing is 1.3m. The verticality of the module is calibrated by a level (deviation ≤1°).

[0025] Installation of pressure-bearing and force-transmitting structure: Laying the top plate pressure main distribution plate (7): Cover all core energy-absorbing modules with 20mm thick Q690 steel distribution plates, and install 40Cr spherical washers (72) at the connection between the distribution plate and the module; Welding transverse auxiliary support ribs (71): Weld one 100mm×10mm Q355 steel support rib every 1.5m along the longitudinal direction below the distribution plate, with a welding height ≥8mm, to ensure no false welding.

[0026] Filling layer filling: Lay a polymer dustproof net (81) on the roof rock wall of the roadway, with an overlap width of ≥100mm and fixed with steel nails; Filling high-strength compressed wood layer (82): Fill the space between the dustproof net and the distribution plate with compressed wood (500mm×200mm×100mm) mixed with 10% magnesium hydroxide and 2% carbon black, with a gap of ≤5mm between the compressed wood splices; Embedded stainless steel support plate (83): Embed a 100mm×100mm×3mm stainless steel support plate every 1m in the compressed wood layer to ensure that the support plate fits the distribution plate.

[0027] Joint support connection: Install constant resistance large deformation anchor bolts (10): anchor bolt spacing 1.2m, anchoring depth 3.5m, pre-tightening force 120kN; connect support coordination control unit (9): connect the unit to the core energy absorption module oil chamber and anchor bolt lock through hydraulic pipeline, adjust the unit trigger threshold (150kN) to ensure that the coordinated pressure relief action is synchronized.

[0028] System commissioning and acceptance: Manually apply a 50kN preload and check the compression stroke of the core energy-absorbing module (should reach 25mm) and the deformation of the distribution plate (≤2mm); simulate a 150kN impact load to verify whether the collaborative control unit triggers the anchor bolt pressure relief, and ensure that the anchor bolt and module pressure relief speed are synchronized (10mm / s); acceptance criteria: installation deviation of each component of the system ≤3mm, load transfer uniformity ≥90%, and flame retardant and antistatic performance meets the requirements of MT / T113-2019.

Claims

1. A hydraulic-spring composite energy-absorbing canopy system for rockburst support in mines, characterized in that, It includes the main support structure, core energy absorption module, pressure-bearing and force-transmitting structure, and filling layer, and can be used in conjunction with constant resistance large deformation anchor bolts / anchor cables (10) to form a collaborative support system; The main support structure consists of an arched frame (1) made of 36U steel and a quick-release pressure relief cable (2). The quick-release pressure relief cable (2) includes a tenon-and-mortise buckle and a mine manual hydraulic pretensioner with a rated pressure of 63MPa. The interface of the arched frame (1) is fitted with a copper alloy wear-resistant bushing (11), and the quick-release pressure relief cable (2) allows the frame to shrink in a controlled manner when the load exceeds 180-250kN. The core energy-absorbing module is fixed to the top beam of the arched shed (1) by the mounting base (3) and is evenly arranged at intervals of 1.2-1.5m along the length of the top beam. The core energy-absorbing module consists of a disc spring assembly (4), a hydraulic damper (5) and a protective shell (6). The disc spring assembly (4) is a detachable stacked structure, including a base plate with a thickness of 8mm and a stiffness of 50kN / mm and an adjusting plate with a thickness of 5mm and a stiffness gradient of 5%-10%. The hydraulic damper (5) is a replaceable valve core structure with a valve core orifice diameter of φ2-φ5mm and a pre-reserved oil filling port (51) in the damper oil chamber. The protective shell (6) is provided with an overload protection pin (61) and a 20mm thick polyurethane spare buffer pad (62). The inner wall of the protective shell (6) is coated with a mining lithium-based dustproof lubricating grease layer (63), and a drain hole (64) with a diameter of φ5mm and a one-way valve is opened at the bottom. The pressure-bearing and force-transmitting structure includes a top plate pressure main distribution plate (7) made of Q690 high-strength steel with a thickness of 20mm, and a transverse auxiliary support rib (71) made of Q355 steel with a cross section of 100mm×10mm. The transverse auxiliary support rib (71) is set at a spacing of 1.5m along the longitudinal direction below the main distribution plate (7). The connection between the main distribution plate (7) and the core energy-absorbing module is provided with a spherical washer (72) made of 40Cr material. The filling layer is a composite functional filler (8) that fills the space between the main pressure distribution plate (7) of the roof and the rock wall of the roadway. From top to bottom, it consists of a 0.5mm diameter polymer dustproof net (81), a high-strength compressed wood layer (82) with a density of 0.8g / cm³ and a compression rate of 30%, and a 3mm thick and 100mm×100mm mining stainless steel support sheet (83). The compressed wood layer (82) contains 10% magnesium hydroxide and 2% carbon black. The system also includes a mining intrinsically safe support coordination control unit (9). The coordination control unit (9) is connected to the oil chamber of the core energy absorption module and the locking device of the constant resistance large deformation anchor (10) through the mining hydraulic pipeline. When the impact load borne by the core energy absorption module is ≥150kN, the coordination control unit (9) adjusts the locking device pressure of the constant resistance anchor (10) to increase the anchor pressure relief speed from 5mm / s to 10mm / s.

2. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The disc spring assembly (4) can adjust the total stiffness of the spring from 100 to 300 kN / mm by increasing or decreasing the number of adjustment plates, and can be adapted to impact energy of 100 to 500 kJ.

3. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The hydraulic damper (5) adjusts the damping coefficient by 50-200kN·s / m by replacing the valve core, adapting to the energy dissipation requirements under different impact loads, and adapting to the underground temperature of -20℃ to 80℃.

4. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The disc spring assembly (4) and the hydraulic damper (5) are connected in parallel or in series. Parallel connection is selected for moderate impact, and series connection is selected for heavy impact. They are encapsulated together in the protective shell (6).

5. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The overload protection pin (61) inside the protective shell (6) shears off when the impact load causes the displacement to exceed the maximum stroke of 200mm, triggering the backup buffer pad (62) to buffer.

6. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The transverse auxiliary support rib (71) is used to prevent the main distribution plate (7) from bending and deforming in a roadway with a span of ≥5m.

7. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The spherical washer (72) is adapted to a slight tilt of ≤3° during the installation of the scaffold, ensuring that each energy-absorbing module is subjected to uniform force.

8. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The polymer dustproof net (81) is covered on the side of the rock wall to prevent rock debris from falling and coal dust from seeping in. The overlap width of the net is ≥100mm and it is fixed with steel nails.

9. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The stainless steel support plate (83) is embedded in the compressed wood layer (82) every 1m to improve the filling layer's resistance to long-term collapse and make the compression of the filling layer ≤8%.

10. The hydraulic-spring composite energy-absorbing canopy system for mine rockburst support according to claim 1, characterized in that, The constant resistance large deformation anchor (10) has an installation spacing of 1.2m, an anchoring depth of 3.5m, and a preload of 120kN.

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