Anchor cable shed support method

Abstract

The present invention discloses an anchor cable shed type support method, which relates to the field of coal mining support methods. The present invention comprises the following steps: cutting an I-beam long beam, welding a vertical support plate and an inclined steel plate at both ends of the bottom surface; drilling oblique anchor cable holes and oblique anchor cable through holes at both ends of the I-beam long beam, and drilling a vertical anchor cable hole in the middle; welding end fixing ribs on both sides and installing triangular side support plates, and welding a middle fixing rib in the middle; laying a steel mesh on the top plate and driving a top anchor rod; arranging the I-beam long beam in a forward direction, driving and fixing vertical anchor cables and oblique anchor cables, laying a steel mesh on the side of the tunnel wall and driving a side anchor rod. The anchor cable shed type support method provided by the present invention solves the problems existing in traditional commonly used support methods, enriches the connotation of large-span tunnel support under special conditions, has value and significance for exploring the theory and practice of tunnel support under special conditions, and is a method that has been proven to be effective in solving large-span tunnel support under special conditions.

Description

Technical Field

[0001] The invention relates to the field of coal mine mining support methods, in particular to an anchor cable shed type support method. Background Art

[0002] Taking the C5# layer 5207 lane of Tongfa Dongzhouyao Mine in Shanxi Province as an example, the Tongfa Dongzhouyao Mine in Shanxi Province is a tens of millions of tons mine with a large tunnel cross-section span and complex geological conditions. It is affected by faults, sinkholes, igneous rock intrusions, fracture zones, stress concentration areas, and water-spraying areas. The excavation tunnel roof has high crushing pressure, and the advanced section of the fully mechanized mining face drift has serious deformation and sinking. The C5# layer 5207 lane is a fully mechanized mining drift with a width of 5m. It is excavated along the bottom plate of the coal seam and has a top coal thickness of about 6m. The gravel-containing coarse sandstone roof on the upper part of the coal seam has an average thickness of 24.51 meters. The coal-rock interface is poorly bonded and prone to separation. The design involved anchor mesh steel belts and cable support. φ22×2400mm anchor rods were initially installed. Single-point anchor cables, φ21.8×8300mm, were then installed vertically from the roof, extending 2 meters into the stable gravel-bearing coarse sandstone strata above the coal seam for reinforced support. Three anchor cables were installed in rows, each 2 meters apart, to prevent the top coal seam from separating and collapsing from the rock strata. From August 1 to 20, 2021, the roadway encountered a gravel-bearing coarse sandstone aquifer at the top of the 600-700-meter tunnel. While no water flowed through the anchor cable holes during construction in the coal seam, water flowed through the holes as they penetrated the top coal and entered the rock stratum, with a flow rate of approximately 1-3 m³ / h per hole. This water flow affected both construction personnel and anchor cable installation, while also impacting anchoring quality, significantly reducing preload and anchoring force. Anchor loss and disengagement during lifting and pulling became common, and in severe cases, the anchor could no longer be anchored, threatening production safety. However, using short anchor cables to anchor in coal and not in stable rock formations can easily cause roof separation and collapse.

[0003] In the existing large-scale mine production, large-span coal mine tunnels encounter special conditions such as soft and broken layered rock layers, joint and fissure development areas, faults, sinkholes, igneous rock intrusion areas, scour zones, water sprinkling areas, pressure-affected areas, tunnel surrounding rock deformation and subsidence areas, stress concentration areas, tunnel intersections, chambers and tunnel openings. Normal tunnel support cannot meet their needs, and the existing commonly used support methods have many shortcomings, as follows.

[0004] (1) Pre-grouting or polymer materials. Pre-grouting or polymer materials is a method of pre-reinforcement of soft and broken surrounding rock before excavation. It is a pre-reinforcement method that assists support and cannot replace support. In addition, it requires special materials and equipment, has many processes, and is costly.

[0005] (2) Densification and strengthening of the original support. By using longer and thicker anchor rods (cables), reducing the row spacing, and increasing support, a continuous composite beam or arch is formed in the surrounding rock, which improves the stress state of the surrounding rock and increases the stability and bearing capacity of the surrounding rock. This is suitable for small-span tunnels with relatively stable surrounding rock. However, for soft and broken surrounding rock with large cross-sectional spans and large deformation, anchor rod (cable) point support is difficult to form a continuous structure in the broken rock mass, and the effect is not good.

[0006] (3) Traditional cable-beam support. Figure 2 As shown, the traditional cable-beam support is a steel beam (or JM beam) that is locked by several anchor cables to support the roof. Multiple anchor cables lock long beams, and long beams are combined with anchor cables. The support area is large and the integrity is good. It can overcome the shortcomings of small area and poor integrity of single-point anchor cables, and overcome the shortcomings of passive and pre-tightening force of shed-type support, and has the advantages of both shed-type and anchor cable support. The beam length and anchor cables can be adjusted according to conditions, with strong adaptability and wide application. However, there are also many problems. The vertical anchor cables of traditional cable-beam support do not extend into the stable rock layer that has not collapsed. The large-section tunnel roof that is soft, broken, affected by the structure, and has weak interlayers may collapse. The traditional cable-beam support cannot bear the delamination and the collapsed broken body of this part and collapses along with it; Figure 3 As shown, the anchor cable (4) is inserted into the forward-arranged I-beam (1), and the end of the anchor cable (4) is locked by the steel washer (2) and the anchor cable lock (3). The forward-arranged I-beam has a strong bending resistance, but the opening of the anchor cable hole causes serious damage to the beam ribs, which reduces the bending resistance of the beam and makes it easy to break at the opening after being subjected to force; Figure 4 As shown, the anchor cable (4) is inserted into the laterally arranged I-beam (1), and the end of the anchor cable (4) is locked by the steel gasket (2) and the anchor cable lock (3). The lateral arrangement of the opening on the beam causes less damage to the ribs, but the bending resistance is weak, and the vertical edge of the beam and the top plate are in line contact rather than surface contact; the anchor cable centering angle is small, generally 10°, and the side anchor cable is almost straight on the top plate. The anchor end is difficult to extend into the upper solid rock layer of the tunnel wall, especially when the top rock is soft and broken, thick, or joints and fissures are developed. When the anchor end cannot extend into the upper stable rock layer, it is easy to cause the cable beam and the soft and broken rock layer to be cut off along the two side lines, causing serious consequences.

[0007] (4) Combined anchor cable support. Combined anchor cable support uses 3-5 anchor cables of different lengths to lock a large tray (generally a 600*600*16mm steel tray) to support the roof. The support area and strength are increased. It is suitable for strengthening support of large-span sections or intersections with relatively good surrounding rock integrity, as well as broken and sunken rock masses. However, the support workload is large and it is only applicable in special circumstances. The cost is high.

[0008] (5) Scaffolding support. Scaffolding support is a traditional passive support that cannot provide high preload and has many shortcomings in strength and effectiveness. It has many processes, complex techniques, heavy workload, and slow progress, and is gradually being reduced or replaced in modern production. However, its good integrity, large support area, and passive support characteristics, combined with anchor-net spraying support, a combination of active and passive, still play an irreplaceable role in strengthening support for soft rock formations under extreme conditions, structural influence zones, and broken subsidence zones, as well as preventing and controlling roof collapse in small-span tunnels.

[0009] In summary, when addressing the problem of supporting large-span roadways under special conditions, current conventional support methods suffer from various problems and shortcomings, including single methods, one-sided concepts, insufficient strength, poor adaptability, poor performance, complex processes, high workload, and high costs. Therefore, it is necessary to study practical support methods for large-span roadways under special conditions and explore practical support technologies to address these issues. Summary of the Invention

[0010] The present invention aims to address various problems and shortcomings of conventional support methods, such as single method, one-sided concept, insufficient strength, poor adaptability, poor performance, complex process, heavy workload, and high cost, when encountering special conditions such as soft and broken layered rock, joint and fissure development zones, faults, collapse columns, igneous rock intrusion zones, scour zones, water-sprinkling zones, pressure-affected zones, deformation and subsidence zones of tunnel surrounding rock, stress concentration zones, tunnel intersections, chambers, and tunnel openings. By absorbing the advantages of conventional support methods and improving their shortcomings, the present invention proposes a large-span tunnel support technology that meets practical special conditions based on field applications, and provides an anchor shed-type support method.

[0011] The present invention is implemented by the following technology: The present invention provides an anchor cable shed type support method, comprising the following steps:

[0012] a. Cut off a long I-beam, which consists of an upper flange, a web, and a lower flange. A vertical support plate is vertically welded to each end of the bottom surface of the lower flange. The width of the vertical support plate is consistent with the width of the lower flange. An inclined steel plate is welded between the bottom end of each vertical support plate and the bottom surface of the lower flange. The width of the inclined steel plate is consistent with the width of the lower flange, thus forming a triangular area.

[0013] b. Oblique anchor cable holes are respectively opened at both ends of the I-beam long beam, passing through the lower flange, web and upper flange. Oblique anchor cable holes corresponding to the oblique anchor cable holes are opened on the inclined steel plate for the installation of oblique anchor cables; vertical anchor cable holes are opened in the middle of the I-beam long beam, passing through the lower flange, web and upper flange for the installation of vertical anchor cables;

[0014] c. Weld end fixing ribs between the upper flange and the lower flange on both sides of the inclined anchor hole at the end of the I-beam long beam, and weld and install triangular side support plates on both sides of the triangular area surrounded by the lower flange, the vertical support plate and the inclined steel plate, so that the strength of the I-beam long beam is not reduced after the hole is opened, and the strength of the inclined steel plate is strengthened; weld middle fixing ribs (18) between the upper flange (101) and the lower flange (103) on both sides of the vertical anchor hole (16) in the middle of the I-beam long beam (1), so that the strength of the I-beam long beam is not reduced after the hole is opened;

[0015] d. Excavate the tunnel section to obtain a flat roof. When the roof is broken and difficult to retain, reduce the cycle footage. After the rough section is excavated, spray concrete first to fill the pits and level the concave parts, or brake the roof at the local super-high point, and then obtain the flat roof. Lay steel mesh on the roof and drive rows of top anchors vertically upward. The steel mesh and top anchors cooperate to form a top anchor net support, which can increase the support area and integrity. You can also spray concrete on the outer layer to enhance the support integrity.

[0016] e. Arrange the I-beam between the two rows of top anchor rods in a positive direction, with the upper flange of the I-beam in close contact with the top plate; according to the position of the vertical anchor cable hole opened in the middle of the I-beam, drive the vertical anchor cable on the top plate, with the anchoring end of the vertical anchor cable deep into the top plate, and the locking end of the vertical anchor cable outside the vertical anchor cable hole on the lower flange, fixed by steel gaskets and anchor cable locks; according to the position of the inclined anchor cable hole opened at the end of the I-beam, drive the inclined anchor cable on the top plate, with an elevation angle of 60°~70°, and the length of the inclined anchor cable can be shorter than the vertical anchor cable hole. Straight anchor cable: The anchoring ends of the inclined anchor cables enter the upper solid rock layer of the tunnel walls on both sides. The tension point of the anchoring end enters 1.5-2m into the tunnel wall in the horizontal direction. The locking end of the inclined anchor cable passes through the inclined anchor cable hole and is located outside the inclined anchor cable hole of the inclined steel plate. It is fixed by steel washers and anchor cable locks. The angle between the inclined anchor cable and the I-beam is complementary to the angle between the inclined steel plate and the I-beam. After assembly, the I-beam and the top plate form a whole, forming a narrow shed-type small structure with the inclined anchor cable locking point as the shed leg and the long steel beam as the shed beam.

[0017] f. Lay steel mesh on the pressure-bearing wall of the side of the tunnel wall, and install anchor rods to form a protection support, which can improve the bearing capacity of the two sides and form a broad shed-type large structure with the top extruded composite beam as the shed beam and the pressure-bearing wall of the side as the shed leg. The narrow shed-type small structure and the broad shed-type large structure form an anchor shed-type support structure, which is formed by the joint action of anchor cables, steel beams and rock strata.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] For example, the excavation of Lane 5207 in the C5# layer, which passes through the top aquiferous rock layer, was a drift tunnel in the fully mechanized mining face. The original design employed anchor mesh steel belts and anchor cables, with φ21.8×8000mm anchor cables. From August 1 to 20, 2021, during the 600m to 700m section of the tunnel, the tunnel encountered a gravelly coarse sandstone aquifer at the top. The top coal layer was approximately 6m thick. As the anchor cable holes penetrated the top coal and entered the rock layer, water gushed out of the holes, with a flow rate of approximately 1-3m³ / h per hole. This water gushed severely into the anchor cable anchoring quality and effectiveness. The anchor cable shed type support method of the present invention is adopted, with a steel beam of 4 meters in length, a beam spacing of 1 meter, a φ21.8×6000mm anchor cable, an elevation angle of 60° for the inclined anchor cables on both sides, a spacing of 3 meters for the inclined anchor cables, and the anchoring end of the inclined anchor cable entering 1.8 meters into the tunnel wall in the horizontal direction and 4.8 meters above the top in the vertical direction; a middle anchor cable, the anchoring end of the middle anchor cable entering 5.6 meters from the top in the vertical direction, and the anchoring end of the anchor cable not entering the water-bearing rock formation, which is convenient for construction, safe and reliable, fast in progress, greatly shortens the construction period, solves on-site problems, plays an important role in quickly and safely passing through the top water-bearing rock formation, and conveniently, quickly and effectively solves the problems that arise.

[0020] The present invention adopts an anchor cable shed-type support method suitable for supporting large-span rectangular cross-section tunnels under special conditions. In this invention, inclined anchor cables at both ends are used instead of vertical roof plates, so that the anchor ends are not located on the upper part of the tunnel roof, but instead penetrate deep into the upper part of the solid rock layer of the tunnel wall. This allows both ends of the entire extruded composite beam to penetrate deep into the tunnel wall, with the side bearing wall as the support and force point, resulting in greater integrity and higher strength. Anchor-type support is the primary method, supplemented by shed-type support, or a combination of anchor and shed support; surface-type support is the primary method, supplemented by point-type support, or a combination of surface and point support. It absorbs the advantages of traditional support and overcomes the shortcomings of traditional support methods such as small support area of ​​traditional anchor rods (cables), difficulty in forming continuous structures in broken rock masses, weak bending resistance of traditional cable-beam support, difficulty in extending side anchor cables into stable rock formations, small support area of ​​traditional combined anchor cables, large support workload and high cost, and no pre-tightening force, complex process, large workload and high cost of scaffolding support. The anchor cables, steel beams and rock formations work together to absorb the advantages of traditional combined anchor cables, lock beams and scaffolding support, and have the advantages of active and passive support, point and surface support, anchor and scaffolding support, with strong flexibility and adaptability. Through structural analysis and establishment of mechanical models, the stability of the surrounding rock can be improved. The comprehensive application of the theories of fixed-support beams and reduced-span beams, natural equilibrium arch theory, extruded composite rock beam theory, surrounding rock stress state theory, stiffness and deflection theory, and rod stability theory to the field of large-span roadway support under special conditions has achieved surrounding rock control under special conditions through microscopic mechanisms and macroscopic perspectives. The support system and overall structure are constructed based on mechanical analysis and surrounding rock control mechanisms. This solves the problems existing in traditional commonly used support methods for large-span roadways under special conditions, enriches the connotation of large-span roadway support under special conditions, explores the theory and practice of roadway support under special conditions, and is a proven and effective method for solving large-span roadway support under special conditions. It has the advantages of convenient process, low cost, safety, reliability, and practicality, and has theoretical and practical significance for large-span roadway support and surrounding rock control under special conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional rendering of the anchor cable shed type support in the present invention is shown.

[0022] Figure 2 Schematic diagram showing the structure of traditional cable-beam support.

[0023] Figure 3 Schematic diagram showing the forward arrangement of long beams.

[0024] Figure 4 Schematic diagram showing the lateral arrangement of long beams.

[0025] Figure 5 A front view showing the installation positions of the inclined steel plates and the vertical support plates in the present invention.

[0026] Figure 6A side view showing the installation positions of the inclined steel plates and the vertical support plates in the present invention.

[0027] Figure 7 A diagram showing the installation position of the inclined anchor cable in the present invention.

[0028] Figure 8 It shows the anchor shed type support structure and mechanical mechanism under small span.

[0029] Figure 9 It shows the anchor shed type support structure and mechanical mechanism under large span.

[0030] Figure 10 1. A processing design drawing of an I-beam long beam according to an embodiment of the present invention is shown.

[0031] Figure 11 It shows the processing front view of the inclined steel plate and the vertical support plate in the embodiment of the present invention.

[0032] Figure 12 It shows the processing side view of the inclined steel plate and the vertical support plate in the embodiment of the present invention.

[0033] Figure 13 It shows the cross-sectional effect of the anchor shed type support in the embodiment of the present invention.

[0034] Figure 14 It shows the plan layout of the anchor shed type support in an embodiment of the present invention.

[0035] In the figure: 1-I-beam long beam, 101-upper flange, 102-web, 103-lower flange, 2-steel gasket, 3-anchor lock, 4-anchor cable, 5-vertical anchor cable, 6-oblique anchor cable, 7-steel mesh, 8-top anchor rod, 9-guard anchor rod, 10-pressure wall, 11-side support plate, 12-vertical support plate, 13-oblique anchor cable hole, 14-inclined steel plate, 15-end fixing rib, 16-vertical anchor cable hole, 17-oblique anchor cable through hole, 18-middle fixing rib, 19-extruded composite beam. DETAILED DESCRIPTION

[0036] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0037] Taking the top water-bearing rock layer of the 5207 lane in the C5# layer as an example, the anchor cable shed support method designed in the present invention includes the following steps:

[0038] a, such as Figure 1 As shown, cut off the 4m long 11# I-beam long beam 1, as shown Figure 6 As shown, the I-beam long beam 1 includes an upper flange 101, a web 102 and a lower flange 103. Figure 5 、 11As shown, a vertical support plate 12 is vertically welded and fixed at both ends of the bottom surface of the lower flange 103. The vertical support plate 12 is 110 mm long, 90 mm wide, and 12 mm thick. The width of the vertical support plate 12 is consistent with the width of the lower flange 103. A bevel steel plate 14 is welded at an angle of 60° between the bottom end of each vertical support plate 12 and the bottom surface of the lower flange 103. The bevel steel plate 14 is 233 mm long, 90 mm wide, and 12 mm thick. The width of the bevel steel plate 14 is consistent with the width of the lower flange 103, thereby forming a triangular area.

[0039] b, such as Figure 10 As shown, inclined anchor cable holes 13 are respectively opened at both ends of the I-beam long beam 1, and the inclined anchor cable holes 13 pass through the lower flange 103, the web 102 and the upper flange 101, with a hole diameter of 25 mm, and the distance between the two inclined anchor cable holes 13 is 3 m. The inclined steel plate 14 is provided with inclined anchor cable through holes 17 corresponding to the inclined anchor cable holes 13 for installing the inclined anchor cables 6; a vertical anchor cable hole 16 is opened in the middle of the I-beam long beam 1, with a hole diameter of 25 mm, and the vertical anchor cable hole 16 is 1.5 m away from the inclined anchor cable holes 13 on both sides. Multiple vertical anchor cable holes can also be opened, and the number of vertical anchor cable holes is determined according to the actual requirements of the span section. The vertical anchor cable hole passes through the lower flange 103, the web 102 and the upper flange 101 for installing the vertical anchor cable 5;

[0040] c, such as Figure 6 、 12 As shown, 12mm thick end fixing ribs 15 are welded between the upper flange 101 and the lower flange 103 on both sides of the inclined anchor cable hole 13 at the end of the I-beam long beam 1, so that the strength of the I-beam long beam 1 is not reduced after the opening is pierced, and it is not easy to break or crack at the opening. Triangular side support plates 11 are welded and installed on both sides of the triangular area surrounded by the lower flange 103, the vertical support plate 12 and the inclined steel plate 14 to strengthen the strength of the inclined steel plate 14; Figure 10 As shown, intermediate ribs 18 are welded between the upper flange 101 and the lower flange 103 on both sides of the vertical anchor cable hole 16 in the middle of the I-beam long beam 1, so that the strength of the I-beam long beam 1 is not reduced after the hole is punched, solving the problem of the traditional cable beam being damaged, reduced in strength and easy to break after the hole is opened;

[0041] d, such as Figure 13 、 14 As shown, a flat roof is taken from the excavated tunnel section. When the roof is broken and difficult to retain, the cycle footage is reduced. After the rough section is excavated, initial concrete is sprayed to fill the pits or depressions, or the roof is braked at the local super-high point, and then the flat roof can be taken. A φ6×100×100mm steel mesh 7 is laid on the roof, and rows of top anchor rods 8 are driven vertically upward. The anchor rod specification is φ22×2400mm, and the row spacing is 1000×900mm. The steel mesh 7 and the top anchor rod 8 cooperate to form a top anchor rod net support.

[0042] e, such as Figure 14 As shown, between the two rows of top anchor rods 8, an I-beam long beam 1 is arranged in the positive direction every 1m, and the upper flange 101 of the I-beam long beam 1 is in close contact with the top plate; according to the position of the vertical anchor hole 16 opened in the middle of the I-beam long beam 1, a vertical anchor cable 5 is set on the top plate, and the number and spacing of the vertical anchor cables are determined according to the actual needs of the span section. Different numbers and spacings can adapt to different span section requirements, with strong flexibility and adaptability. The anchoring end of the vertical anchor cable 5 penetrates into the top plate and enters the top 5.6m in the vertical direction. The locking end of the vertical anchor cable 5 is in the vertical anchor hole 103 of the lower flange. 6, fixed by steel gasket 2 and anchor lock 3; according to the position of the inclined anchor hole 13 opened at the end of the I-beam long beam 1, a φ21.8×6000mm inclined anchor cable 6 is set on the top plate with an elevation angle of 60°. The inclined anchor cable enters the upper solid rock layer of the roadway on both sides, and enters the stable rock layer on both sides of the natural balance arch of the broken soft rock layer, which can effectively prevent the soft and broken rock in the arch from collapsing together with the cable beam. It enters 1.8m inside the roadway in the horizontal direction and 4.8m above the top in the vertical direction without entering the water-bearing rock layer, which is convenient for construction, safe and reliable, and greatly shortens the construction period. Figure 7 As shown, the locking end of the inclined anchor cable 6 passes through the inclined anchor cable hole 13 and is located outside the inclined anchor cable through hole 17 of the inclined steel plate 14, and is fixed by the steel gasket 2 and the anchor cable lock 3. The angle between the inclined anchor cable 6 and the I-beam long beam 1, and the angle between the inclined steel plate 14 and the I-beam long beam 1, are complementary angles to each other; the assembled I-beam long beam 1 and the top plate form a whole, forming a narrow shed-type small structure with the inclined anchor cable locking point as the shed leg and the 4m long 11# I-beam long beam 1 as the shed beam. Compared with the traditional shed structure, by organically integrating with the anchor cable support, the shed leg is eliminated, the workload is reduced, the shed beam is actively pre-tightened, and the disadvantage of the passive isobaric pressure of the traditional shed is completely changed. It is much better than the traditional shed support in terms of construction technology, support strength and effect.

[0043] f. Steel mesh 7 is laid on the 1.8m-wide bearing wall 10 at the side of the tunnel, and support anchors 9 are installed. The support anchors are φ22×2400mm, with a row spacing of 1000×900mm. The steel mesh is φ6×100×100mm. This provides support and improves the bearing capacity of both sides. A broad-based shed-like structure is formed, with an 8.6m-long (tunnel width + twice the bearing wall width) and 4.8m-high top extruded composite beam as the shed beam, and the bearing wall as the shed legs. This anchor cable shed-like support structure, composed of a narrow-based shed-like small structure and a broad-based shed-like large structure, forms a combined anchor cable shed. The anchor cables, steel beams, and rock formations work together to effectively support the overlying rock formation and protect the underlying space. The length and spacing of the steel beams, the number and spacing of the intermediate anchor cables, the inclination angle of the diagonal anchor cables, and the specifications of the anchor cables can be flexibly adjusted based on the specific tunnel width and roof conditions.

[0044] The mechanical analysis of the anchor shed support method is as follows:

[0045] Analyze from the locking end of the lower part of the inclined anchor cable: in the vertical direction, if Figure 8 As shown in FIG. 1 , the vertical component F2′ of the inclined tension F′ at the lower locking end of the inclined anchor cable 6 acts on the top plate through the I-beam 1. Compared with the single-point anchor cable, it can form a relatively uniform, continuous and symmetrical upward compressive stress σ2′ on the top plate; Figure 9 As shown in the figure, when there is a vertical anchor cable 5, the compressive stress σ3' is greater than the compressive stress σ2', which further improves the vertical stress state of the extruded composite beam, makes the top rock layer vertically squeezed, and forms a strong extruded composite beam. Figures 8 and 9 As shown, the horizontal component F1' of the oblique tension F' at the lower locking end of the oblique anchor cable 6 forms a balanced horizontal tension of equal magnitude and opposite direction at both ends of the I-beam long beam 1, forming a uniform tensile stress inside the steel beam, which can increase the rigidity of the I-beam long beam 1, enhance the stability of the steel beam as a rod, and reduce the bending deflection of the steel beam, which is very beneficial to increasing the stability and bending resistance of the steel beam. At the same time, the reverse tightening horizontal force of the I-beam long beam 1 on the oblique anchor cable 6 can horizontally squeeze and reinforce the rock layer below the top plate.

[0046] Analyze from the upper anchorage end of the inclined anchor cable: in the vertical direction, if Figures 8 and 9 As shown in the figure, the downward vertical component F2 of the inclined tension F at the upper anchorage end of the inclined anchor cable, together with the downward vertical tension F3 of the middle anchor cable, and the upward vertical component F2' of the inclined tension F' at the lower locking end of the inclined anchor cable, together with the upward vertical pressure F3' of the middle anchor cable, are in opposite directions, forming vertical extrusion stresses σ2, σ3, σ2', and σ3', which work together to squeeze the composite beam, completely improving the vertical stress state of the squeezed composite beam, making the top rock layer vertically squeezed and forming a strong squeezed composite beam 19. In the horizontal direction, as shown in the figure, Figure 8 As shown, the horizontal component F1 of the diagonal tension force F at the upper anchorage end of the inclined anchor cable 6 forms a horizontal compressive stress σ1 at both ends of the extrusion composite beam, further improving the horizontal stress state of the extrusion composite beam and horizontally compacting the top rock strata, forming a strong extrusion composite beam 19. The downward vertical component F2 of the diagonal tension force F at the upper anchorage end of the inclined anchor cable 6, together with the downward weight of the extrusion composite beam and the bearing capacity of the extrusion composite beam on the overlying rock strata, forms a vertical stress σ2, which presses on the two lane walls, forming a bearing wall 10 of a certain width on both sides.

[0047] The long steel beam provides surface support, enclosing the roof over a large area, creating a relatively uniform preload on the roof, which facilitates the formation of a beam structure. The constructed fixed-beam or multi-span beam structures, narrow shed-style small structures, and broad shed-style large structures, promote the concept of combining active and passive support, as well as the integration of anchor cables and shed-style support, which is of considerable value and reference value.

[0048] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various variations and modifications. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. An anchor cable shed type support method, characterized by: The following steps are involved: a. Cutting an I-beam long beam (1), the I-beam long beam (1) comprising an upper flange (101), a web (102) and a lower flange (103), vertically welding and fixing a vertical support plate (12) at both ends of the bottom surface of the lower flange (103), and welding an inclined steel plate (14) between the bottom end of each vertical support plate (12) and the bottom surface of the lower flange (103), thereby forming a triangular area; b. Oblique anchor cable holes (13) are respectively provided through the two ends of the I-beam long beam (1), and oblique anchor cable holes (17) corresponding to the oblique anchor cable holes (13) are provided on the inclined steel plate (14); a vertical anchor cable hole (16) is provided through the middle of the I-beam long beam (1); c. Welding end fixing ribs (15) between the upper flange (101) and the lower flange (103) on both sides of the inclined anchor hole (13) at the end of the I-beam (1), and welding and installing triangular side support plates (11) on both sides of the triangular area surrounded by the lower flange (103), the vertical support plate (12) and the inclined steel plate (14); and welding middle fixing ribs (18) between the upper flange (101) and the lower flange (103) on both sides of the vertical anchor hole (16) in the middle of the I-beam (1); d. Excavate the tunnel section to obtain a flat roof, lay a steel mesh (7) on the roof, and vertically drive rows of top anchor rods (8), wherein the steel mesh (7) and the top anchor rods (8) cooperate to form a top anchor rod mesh support; e. Arrange an I-beam (1) between two rows of top anchor rods (8) in a positive direction, wherein the upper flange (101) of the I-beam (1) is in close contact with the top plate; according to the position of the vertical anchor cable hole (16) opened in the middle of the I-beam (1), a vertical anchor cable (5) is driven on the top plate, the anchoring end of the vertical anchor cable (5) penetrates into the top plate, and the locking end of the vertical anchor cable (5) is fixed outside the vertical anchor cable hole (16) of the lower flange (103) through a steel gasket (2) and an anchor cable lock (3); according to the inclined anchor cable hole (16) opened at the end of the I-beam (1), the vertical anchor cable (5) is driven into the top plate, and the locking end of the vertical anchor cable (5) is fixed outside the vertical anchor cable hole (16) of the lower flange (103) through a steel gasket (2) and an anchor cable lock (3); At the location of the cable hole (13), an inclined anchor cable (6) is installed on the top plate. The angle between the inclined anchor cable (6) and the I-beam (1) and the angle between the inclined steel plate (14) and the I-beam (1) are complementary angles. The anchoring ends of the inclined anchor cables (6) enter the upper solid rock layer of the tunnel walls on both sides. The locking ends of the inclined anchor cables (6) pass through the inclined anchor cable holes (13) and are located outside the inclined anchor cable holes (17) of the inclined steel plate (14), and are fixed by steel washers (2) and anchor cable locks (3). After assembly, the I-beam (1) and the top plate form a whole. f. Lay a steel mesh (7) on the bearing wall (10) of the tunnel side and install a side support anchor rod (9) to form a side support.

2. The anchor cable shed type support method according to claim 1, characterized in that: In step a, the width of the vertical support plate (12) is consistent with the width of the lower flange (103), and the width of the inclined steel plate (14) is consistent with the width of the lower flange (103).

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