GB 25974.1-2026Powered support for coal mine - Part 1: General technical specification (English PDF)

4.1.1 Pedestrian walkway

4.1.1.1 The width of the pedestrian walkway within the basic support structure shall not be less than 0.6m and the height shall not be less than 0.4m.

4.1.1.2 When in use, the bracket should not have any protruding parts that would obstruct walking within pedestrian range.

4.1.1.3 Anti-slip measures that comply with coal mine safety regulations should be taken for the surfaces to be stepped on.

4.1.1.4 When working in inclined coal seams, there should be devices that comply with coal mine safety regulations to ensure pedestrian safety.

4.1.2 Dust suppression and leak prevention device

4.1.2.1 The basic support structure should be equipped with a dust suppression device.

4.1.2.2 The structure of the support should provide safe protection for pedestrian passages and prevent gangue from entering the working face space from the roof and goaf.

4.1.3 Protection of Hydraulic Components

4.1.3.1 When the support is working as specified, its structural components shall not cause damage to the hydraulic components on the support.

4.1.3.2 Protective devices should be provided at the connection points of the main inlet and outlet pipelines of the support to prevent the pipeline joints and accessories such as U-pins from falling off.

4.1.4 Anti-scraping device When the mining height is greater than or equal to 3m, the basic support should be equipped with side guard plates. The length of the side guard plates should be determined based on the coal seam conditions and equipment requirements of the working face. Once the supporting conditions are determined, the side guard plate must be locked when it is in operation and when it is retracted, and the side guard jack should be equipped with a safety valve.

4.1.5 Anti-tipping and anti-slip When the working face inclination angle is greater than 15°, the hydraulic support should take measures to prevent tipping and slipping; when the inclination angle is greater than 25°, measures should be taken to prevent coal (gangue) from escaping and being scraped. Measures to prevent injuries caused by plate conveyors.

4.1.6 Lifting Point The entire support frame and its main components should be equipped with lifting points, and the structure of these lifting points should be able to withstand a static load of four times the lifting weight; the lifting points should have permanent supports. (For example, by welding) Clearly mark the lifting weight at the lifting points of the entire frame.

4.1.7 Advanced protection devices When the support frame is used in a mining face with a height greater than 3m or a broken roof, protective devices such as telescopic beams or side guards should be installed.

4.1.8 Assembly performance Similar components of the bracket should be interchangeable and should not be assembled by selection.

4.1.9 Structural Dimensions

4.1.9.1 The height deviation between the minimum and maximum height of the bracket is ±50mm.

4.1.9.2 The width deviation between the minimum and maximum width of the bracket is ±20mm.

4.1.10 Pressure Display A device that can display the pressure in the piston chamber of the column should be installed on the bracket.

4.1.11 Hazard Assessment A hazard assessment should be conducted on the support structure, and measures should be taken to eliminate or reduce various potential hazards. The support structure is prone to [problems/risks] during operation, installation, and maintenance. See Appendix A for details of the hazards and dangerous situations that may occur.

4.2 Appearance Quality

4.2.1 The outer surface of the bracket shall be painted, and the paint layer shall be uniform and free from defects such as missed coating, blistering, peeling, and cracks.

4.2.2 Exposed welds shall comply with the provisions of MT/T 1273-2025.

4.2.3 The appearance of castings shall conform to the requirements of GB/T 11352.

4.2.4 The appearance of forgings shall conform to the requirements of GB/T 12361.

4.2.5 Exposed coatings shall comply with the provisions of GB/T 25974.2-2010.

4.3 Operational Performance The movement of each component of the support should be accurate, flexible, and free from jamming or interference. Each component should be undamaged when it reaches its limit.

4.4 Sealing performance

4.4.1 When the piston chamber of the column and front beam jack is at 90% of the rated working pressure, the pressure should not drop within a specified time.

4.4.2 The column should have good sealing performance. After the piston extends outward, its extension stroke should remain stable under specified conditions, and the retraction amount should not exceed [a certain limit]. Exceeding 2mm (ignoring the effect of temperature).

4.4.3 The front beam jack should have good sealing performance. After the piston rod extends, its extension stroke should remain stable under specified conditions, and the retraction... The amount should not exceed 2mm (not considering the effect of temperature).

4.4.4 Under the rated fluid supply pressure, and in accordance with the specified operation of the support, no external leakage should occur in any hydraulic component.

4.5 Support performance

4.5.1 Under rated liquid supply pressure, the initial support force of the support should not be less than 95% of the rated initial support force at its test height, or the piston chamber pressure of the column. The force should be no less than 95% of the rated hydraulic pressure.

4.5.2 When the support reaches its rated working resistance, the pressure in the piston chamber of the column should not exceed 110% of the rated opening pressure of the column safety valve. Less than 90% of the rated opening pressure.

4.5.3 The opening pressure of the safety valve in the working chamber of the front beam jack and the balance jack should not exceed 110% of its rated working pressure, and the safety valve should be closed. The closing pressure should not be less than 90% of the rated working pressure.

4.6 Adaptability

4.6.1 When the moving mechanism is in the retracted position, the amount by which the connecting hole between the connector and the matching conveyor is raised, for thin coal seam supports or those equipped with a bottom lifting mechanism. The support bracket for the seat device should be no less than 100mm, and other brackets should be no less than.200mm; the drop of the connecting hole should not be less than for all types of brackets. 60mm.

4.6.2 When the support frame is raised by 300mm from its minimum height, the sway angle of the top beam should not be less than 5°; for a maximum height greater than or equal to 3m... For scaffolding, at its maximum height, the sway angle of the top beam should not be less than 15°; for scaffolding with a maximum height of less than 3m, the sway angle of the top beam at its maximum height should not be less than 15°. At that time, the tilt angle of the top beam should not be less than 10°.

4.6.3 For brackets with special requirements on the specific pressure of the base plate, the specific pressure of the base plate should be less than the allowable compressive strength requirement of the base plate.

4.7 Improve shrinkage performance The supports used in fully mechanized mining faces should have compressibility to withstand roof subsidence. When the roof subsides and the supports retract, the maximum supporting force should not exceed [a certain value]. 110% of the rated working resistance.

4.8 Structural Strength

4.8.1 Strength of main structural components After the strength loading test, there should be no cracks in the welds or base material of the main structural components of the support frame. The relative residual deformation between the top beam and the base should not exceed [a certain value]. 0.4%; the angle of deviation between the centerline of the top beam and the centerline of the base should not exceed 3°, and other components should not be damaged or have any impact on use. Deformation.

4.8.2 Strength of non-main structural components

4.8.2.1 Top beam side guard plate After the strength loading test, the main load-bearing components of the top beam side guard plate should not be damaged or the welds should not crack, and the residual deformation should not affect the free movement of the side guard plate. Extend.

4.8.2.2 Balancing jack connecting structural components The connecting structural components of the balancing jack should not be damaged or deformed in a way that affects their use after the strength loading test.

4.8.2.3 Side panels After the strength loading test, the structural components of the protective plate should not be damaged or deformed in a way that affects its use.

4.8.2.4 Front beam After the strength loading test, the structural components and connecting structural components of the front beam should not be damaged or deformed in a way that affects its use.

4.8.2.5 Telescopic Beam After the strength loading test, the expansion beam should not have any damage or residual deformation that would affect expansion and contraction.

4.8.2.6 Pushing Mechanism The pushing mechanism should not be damaged or deformed in a way that affects its use after the strength loading test.

4.8.2.7 Column connectors After a single column is contracted at

1.2 times the rated hydraulic pressure, the connecting pins should not exhibit residual deformation. After the hydraulic force is applied to the column to retract

1.5 times, the column base pin is allowed to break, but the other connecting parts should not have any deformation that would affect disassembly or assembly.

4.8.2.8 Base Adjustment Mechanism The bottom adjustment mechanism should not be damaged or deformed in a way that affects its use after the strength loading test.

4.9 Durability No cracking of the base material should occur after the durability test of the bracket. There should be no more than two weld cracks on the same component, and the weld should not have a crack greater than A crack 50mm long; residual deformation should not exceed 0.5% of the corresponding fulcrum distance; warping deformation should not exceed the maximum length of the component in its maximum direction. 0.5%; the angle of deviation between the centerline of the top beam and the centerline of the base should not exceed 3°; all components should not be damaged or have any impact on their use. Deformation.

4.10 Hydraulic Components

4.10.1 Columns and Jacks The support column and jacks shall comply with the provisions of 4.2,

4.6 in GB/T 25974.2-2010.

4.10.2 Hydraulic control system and valves The hydraulic control system and valves of the support frame shall comply with 5.3.2.1~5.3.2.7, 5.3.2.9, 5.3.2.10, and

5.3.3 of GB/T 25974.3-2010. The provisions of 5.3.4.1, 5.3.4.3~5.3.4.7, and 5.3.5.

4.10.3 Hose assemblies and fittings Hose assemblies shall comply with MT/T 98; U-pin quick couplings and accessories shall comply with MT/T 986.

4.11.1 Steel

4.11.1.1 General requirements for steel materials The materials used for the support components should meet the performance requirements specified in the design drawings. The elongation of the material should be no less than 10%; the elongation of the pins should... Not less than 9%.

4.11.1.2 Steel for welded components Killed steel with uniform impurity distribution and stable grains, suitable for welding, should be selected, and should meet the following requirements.

a) Ferrite grain size level greater than or equal to 6;

b) At a temperature of -20°C, the following notch impact energy should be achieved (regardless of the rolling direction of the specimen).

---For steel with a yield strength less than or equal to 620 N/mm^2, the value is 20 J;

---For steel with a yield strength greater than 620 N/mm^2, the value is 25 J.

4.11.1.3 Steel for non-welded components The steel should be deoxidized, and its notched impact energy at 20°C should be no less than 25J.

4.11.1.4 Light Metals The outer surfaces (including coatings, brushes, or platings) of bracket components and accessories should not use light metals or light metal alloys, and should comply with... The provisions of Chapter 8 of GB/T 3836.1-2021.

4.11.2 Other materials Other materials used should meet the design requirements. Non-metallic materials should comply with the provisions of Chapter 7 of GB/T 3836.1-2021.

4.12 Welding Welding operations shall comply with the provisions of GB/T 12467 (all parts).

5.1.1 Test Requirements

5.1.1.1 The test shall be conducted on a complete support, or on a support component or a group of components acting together.

5.1.1.2 After the loading test, the base material of the support component should not be damaged or have deformation or weld cracks that affect its use.

5.1.1.3 All test values and results of the experiment should be fully recorded.

5.1.2 Test Apparatus and Conditions

5.1.2.1 The test apparatus includes an external loading test bench and an internal loading test bench, the loading capacity and height of which shall meet the requirements of the test support.

5.1.2.2 The flow rate and pressure of the working fluid source should be equal to or greater than the design flow rate and pressure of the test support.

5.1.2.3 The liquid supply system should have a pressurization function, capable of pressurizing to

1.5 times the rated working pressure of the tested support; the system may be supplemented with automatic circulation. Loading function.

5.1.2.4 The diameter of the inlet and return pipes connecting the test support should be consistent with or not less than the designed inlet and return pipe diameters.

5.1.2.5 The working fluid shall be a high-water-content solution prepared by mixing emulsified oil or concentrate as specified in MT/T 76 with neutral soft water at a ratio of 5.95 (mass ratio). Hydraulic fluid.

5.1.2.6 During the test, the working fluid temperature shall be controlled between 10°C and 50°C. A 40µm precision filter shall be used for the working fluid, and a magnetic filter shall be provided. Filtering device.

5.1.2.7 The measurement accuracy shall be no less than Class C, and the permissible error of the measurement system shall comply with the provisions of Table 1.

5.1.3 Loading pad The pads used to transfer symmetrical bending loads should have an average specific pressure not exceeding 25 MPa, a width of 150 mm, and a length reaching the specified value. The full width of the component. If the specific pressure during the test exceeds 25 MPa, the pad should be enlarged accordingly. Pads transmitting torsional loads should ensure that the specific pressure does not exceed [a certain value]. 25MPa, width should be.200mm, and length should be 1/4 of the component width; if it is a separable base, the length of the pad should reach under this load. The full width of each individual base. Pads should be placed at the center of force transmission and at the ends of the tested support components, and may also be placed with these locations if necessary. Different settings are used to achieve a stable load. The pad structure should not impede the free and flexible movement of components and should not subject the edges to compression. Its height should ensure that it does not obstruct support during testing. Deformation of frame components.

5.2 Lifting Point Load the lifting point with jacks until it reaches four times the lifting weight, then stop and observe whether the structure of the lifting point undergoes any changes that may affect its use. Deformation or damage. This test is also permitted to be performed as a single test, for example, on a comparable specimen.

5.3 Appearance Quality Perform the inspection using ordinary measuring tools and special measuring instruments under sunlight or normal lighting.

5.4 Operational Performance Operate the directional valve to make each moving part perform the designed action 3 times, each time reaching its limit position.

5.5 Sealing performance

5.5.1 The support is placed inside the test bench, and the test bench height is adjusted to the maximum height of the support minus 1/3 of the support's travel. Operation reverse direction. The valve supplies fluid to the column and related hydraulic cylinders, tightening the support within the test bench and raising the pressure in the piston chamber to the rated working pressure. 90%, stabilize the voltage for 5 minutes, and measure 3 times.

5.5.2 Raise the frame under no-load conditions until the piston rod extends to 2/3 of its full stroke, then let it stand still for 16 hours and measure the piston rod. Retraction amount.

5.5.3 With the bracket equipped with the front beam, raise the front beam under no-load until the piston rod of the front beam jack extends to 2/3 of its full stroke, then bring it to a complete stop. After 16 hours, measure the amount of piston rod retraction.

5.5.4 Operate the directional valve to make each moving part reciprocate and reach its limit position, and operate it 5 times, one of which is at the rated supply pressure. Hold for 5 minutes and inspect hydraulic components (including columns, jacks, valves, hoses and connectors).

5.6 Support performance

5.6.1 The support is placed in an external or internal loading test bench for testing.

5.6.2 Operate the reversing valve to bring the pressure in the piston chamber of the support column to the rated supply pressure, then cut off the supply, stabilize the pressure for 5 minutes, and measure the pressure in the piston chamber of the column. Pressure value, measured 3 times.

5.6.3 After the support column reaches the rated liquid supply pressure, apply external or internal load slowly to cause the safety valve to overflow 2 to 3 times, and measure the column pressure. Piston chamber pressure value. After the safety valve stops discharging for 5 minutes, measure the piston chamber pressure value again, and repeat the measurement 3 times.

5.6.4 Apply slow external or internal loading to the front beam jack and the balance jack until the safety valve overflows 2 to 3 times, and measure the pressure. Value. After the safety valve stops discharging for 5 minutes, measure the jack pressure value again, and repeat the measurement 3 times.

5.7 Adaptability

5.7.1 As shown in Figure 2, when the moving mechanism is in the retracted position and the push rod is in a horizontal state, the connector lifts and falls. Measure the connection of the connector. The center of the hole is lifted by L1 and dropped by L2.

5.7.2 Elevation Angle Measurement. After the support frame is raised to the specified height, the center height of the hinge axis between the top beam and the shield beam remains unchanged. The top beam is then tilted upwards by operation. (Four-post support is achieved through extension columns, and two-post support is achieved through extension columns and adjusting balance jacks); Deflect...