Surrounding rock supporting and reinforcing method in stoping process of steeply-inclined extremely-thin mine body difficult to mine

Abstract

The invention relates to a surrounding rock supporting and reinforcing method in the stoping process of a steeply-inclined extremely-thin difficult-to-mine body, which comprises the following steps: S1, analyzing the stress and displacement evolution law of a rock mass in the stoping process of a shallow hole shrinkage method stope on the basis of numerical simulation, and determining a rock mass tensile stress concentration area and a maximum displacement occurrence area, original ore pillars are reserved in the key supporting intervals to support the upper and lower wall surrounding rocks; s2, sealing the joint and fracture development area of the surrounding rocks of the upper and lower walls by adopting concrete guniting; s3, on the basis of surrounding rock guniting treatment, upper and lower wall surrounding rocks are temporarily supported through cross-braced struts, and then anchor rods are arranged on the upper and lower wall surrounding rocks on the basis of the cross-braced struts for supporting; and S4, for an unstable area where hanging foot wall caving and crushing argillization occur at the junction of the surrounding rock and the vein, a mode of pouring a reinforced concrete beam is adopted for replacing the fractured rock mass. According to the method, safe and efficient stoping of ore body resources is achieved through collaborative means of primary ore pillar supporting, surrounding rock guniting sealing, anchor rod supporting, rock mass replacement and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of mining, and in particular relates to a surrounding rock support and reinforcement method during the mining process of a steeply inclined, extremely thin, and difficult-to-mine body. Background Art

[0002] Steeply inclined, extremely thin, and difficult-to-mine ore bodies are common in underground mining projects. These ore bodies are often characterized by faults, developed joints, and weak interlayers. The surrounding rock structure is unstable, making it highly susceptible to instability during mining. Existing mining processes often face the following problems: First, the complex distribution of the secondary stress field leads to stress concentration, triggering surrounding rock failure; second, the mining process itself disturbs the surrounding rock in the upper and lower walls, which can easily cause instability such as spalling and roof collapse; third, weak structural surfaces weaken the integrity of the rock mass, causing a decrease in strength; fourth, groundwater infiltration weakens the physical and mechanical properties of the rock mass, further reducing its bearing capacity; fifth, the surrounding rock contains clay minerals, which expand upon contact with water, accelerating the surrounding rock's fragmentation process. Furthermore, some granite surrounding rocks are susceptible to instability due to weathering. To address these geological conditions, existing technologies often use methods such as anchor bolting, pre-reserved pillars, or shotcrete sealing to support and reinforce the stope to ensure mining safety and reduce the risk of resource loss.

[0003] However, for steeply inclined, extremely thin ore bodies, due to their small thickness, large inclination, and severe surrounding rock fragmentation, the surrounding rock stability is often even worse when using the shallow hole ore retention method for mining. Although existing technologies usually use temporary support methods to support the upper and lower wall surrounding rock and roof rock, such as cross bracing, anchor support, or the installation of safety pillars, under the influence of weathering and oblique structural fracture zones, it is still unable to effectively suppress rock mass instability and is prone to local collapse. Especially under conditions where the ore-rock interface is severely muddied or the clay interlayer expands when exposed to water, traditional support methods are difficult to achieve structural integrity, resulting in an increased risk of support failure. In addition, existing technologies still lack systematic collaborative design of key links such as support position, support combination, and surrounding rock replacement. As a result, the support effect is limited in the actual mining process, the mining range is difficult to control, and the recovery rate is generally low, only 35% to 55%. This not only causes a large amount of resource waste but also seriously threatens the lives of workers. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a surrounding rock support and reinforcement method suitable for the mining process of steeply inclined, extremely thin and difficult-to-mining ore bodies. Through the coordinated means of primary ore pillar support, surrounding rock grouting sealing, anchor support and rock replacement, the safe and efficient mining of ore resources can be achieved.

[0005] To achieve the above object, the technical solution of the present invention is as follows: A method for supporting and reinforcing surrounding rock during the mining process of a steeply inclined, extremely thin, and difficult-to-mine ore body comprises the following steps: S1: Based on numerical simulation, analyze the stress and displacement evolution of the rock mass during the shallow hole ore retention method stope recovery process, determine the rock mass tensile stress concentration area and the maximum displacement occurrence area, identify the range of one-third to two-thirds of the stope height as the key support area with poor surrounding rock stability, and retain primary ore pillars in this key support area to support the upper and lower wall surrounding rock; S2, after the primary pillars are laid, concrete shotcrete is used to seal the joints and fissures of the surrounding rock in the upper and lower walls, and the slurry is pressed into the joints and fissures of the rock mass by the injection pressure to enhance the bonding force between the rock masses; S3, based on the surrounding rock shotcreting treatment, first use cross bracing pillars to temporarily support the upper and lower wall surrounding rocks, and then lay anchor rods on the upper and lower wall surrounding rocks to improve the stress condition of the stope surrounding rocks and prevent spalling; S4: For unstable areas with overhanging slabs, broken mud and debris at the junction of surrounding rock and ore vein, reinforced concrete beams are cast to replace the broken rock mass to form alternative structural support.

[0006] Preferably, in step S1, three primary pillars are set, one at 1 / 3 of the mining height of the stope and at 1 / 3 and 2 / 3 along the length of the stope, and the other is set at 2 / 3 of the mining height of the stope and in the middle of the length of the stope.

[0007] Preferably, the size of the primary pillar is 4m×4m.

[0008] Preferably, in step S2, the spraying sealing treatment adopts a PZ-5 type spraying machine to spray concrete, the concrete strength is C20, and the amount of accelerating agent used is 5% of the amount of cement.

[0009] Preferably, the sprayed thickness of the concrete is 50 mm.

[0010] Preferably, in step S3, the anchor rod is a φ18mm left-handed threaded steel resin anchor rod with a length of 1.5-1.8m. During installation, the anchor rod should be perpendicular to the surrounding rock surface, and the support plate should be close to the rock surface. The anchoring force should be no less than 50kN and the tightening force should be no less than 100N·m.

[0011] Preferably, for areas with severe weathering and fragmentation, metal steel mesh is added on the basis of anchor rods and shotcrete support.

[0012] Preferably, the steel mesh is made of φ6.5mm steel bars, has a mesh size of 150mm×150mm, and a mesh size of 1m×2m, and is firmly connected to the anchor rods when laid.

[0013] Preferably, in step S4, the pouring of the reinforced concrete beam includes the following construction steps: S41, drilling steel bars along both sides of the stope with a grid size of 30 cm × 25 cm, the drilling depth of which is 1.2 meters; S42, inserting a 1.6-meter-long threaded steel bar into the drill hole, with an exposed length of 0.4 meters, and laying and tying the steel bars along the strike direction of the stope to form a reinforcement structure; S43, before pouring concrete, lay woven bags under the reinforced concrete beams to prevent the concrete from bonding with the slag below; S44, pour concrete and maintain it for at least one week. No mining operations shall be carried out during the maintenance period.

[0014] Preferably, the thickness, width and length of the reinforced concrete beam are determined according to the degree of crushing of the surrounding rock.

[0015] Compared with the prior art, the advantages of the present invention are: The present invention adopts a collaborative support method of primary pillar support, surrounding rock grouting closure, surrounding rock anchor support and broken rock replacement during the mining process of steeply inclined and extremely thin difficult-to-mine ore bodies. It can effectively deal with the instability risks brought about by complex geological conditions such as severe surrounding rock weathering, developed joints and fissures, layered fragmentation structure and mudification at the interface between ore and rock. Leaving primary pillars in key parts of the mining site effectively reduces the exposed area of ​​the upper and lower surrounding rocks, improves the local stress concentration, and enhances the overall stability of the rock mass; spraying concrete on the upper and lower surrounding rocks forms a sealing layer, which can cement the broken rock mass into a whole, isolate it from air and water erosion, and slow down the weathering rate; laying anchor rods and combining them with steel mesh for support can achieve anchoring of unstable surrounding rock in stable rock layers, forming a complete force system to prevent spalling and collapse; for severely broken areas, rock mass replacement is achieved by casting reinforced concrete beams, which can achieve structural rigid support and significantly improve the bearing capacity and safety of the area. In summary, the above-mentioned multi-means coordinated support method can improve the overall stress distribution of the surrounding rock in the mining area, enhance the stability of the surrounding rock, control the mining width, and prevent the occurrence of dangerous situations such as roof falls and rock spalling, thereby achieving safe and efficient recovery of ore resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of the surrounding rock support and reinforcement method of the present invention; Figure 2 is a cross-sectional view of a stope of the present invention; Figure 3 For the present invention Figure 2 Middle AA top view; Figure 4 This is a schematic diagram of the anchor rod arrangement of the present invention; Figure 5 is a side view of the stope of the present invention; Figure 6This is a schematic diagram of pouring a reinforced concrete beam according to the present invention; Figure 7 The present invention is a flow chart of the pouring construction of reinforced concrete beams.

[0017] Figure numerals: 1-primary pillar; 2-surrounding rock; 3-anchor; 4-reinforced concrete beam; 5-threaded steel bar; 6-reinforcement structure. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the present invention.

[0019] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps etc. can be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0020] like Figure 1-7 As shown, this embodiment discloses a surrounding rock support and reinforcement method during the mining process of a steeply inclined, extremely thin, and difficult-to-mine ore body. The method is applicable to the mining process of a steeply inclined, extremely thin, and difficult-to-mine ore body. The mining field is divided into an upper unmined ore body and a collapsed ore in a lower mining area. Such ore bodies generally have characteristics such as a large inclination angle, thin thickness, loose structure, and developed joints and fissures. During the mining process, surrounding rock weathering, spalling, and caving are prone to instability. Conventional support methods are difficult to meet the requirements of safe mining. The surrounding rock support and reinforcement method of this embodiment includes the following steps: S1, based on numerical simulation analysis of the stress and displacement evolution of the rock mass during the mining process of the shallow hole ore retention method, determine the rock mass tensile stress concentration area and the maximum displacement occurrence area, identify the range of one-third to two-thirds of the mining site height as the key support area with poor surrounding rock stability, and leave primary ore pillars in the said key support area to support the upper and lower surrounding rocks.

[0021] In this step, the placement of primary pillars 1 is determined based on numerical simulation results. This effectively reduces the exposed area of ​​surrounding rock 2, improves stress concentration in this area, and thus enhances the overall stability of surrounding rock 2 during mining. For example, a steeply inclined, extremely thin ore body was mined using the shallow hole retention method, with a designed stope size of 50 meters long and 50 meters high. To determine the stability of the surrounding rock during mining, numerical simulation was used to analyze the stress and displacement evolution of the stope at different stages. The simulation results show that when mining reaches a mining height of approximately 15 meters, or one-third of the total stope height, the tensile stress distribution area in the surrounding rock begins to expand rapidly, and the tensile stress in the rock mass increases significantly. When mining continues to a mining height of approximately 33 meters, or two-thirds of the stope height, the tensile stress distribution reaches its maximum, approaching the ultimate tensile strength of the rock mass, making tensile failure highly likely, resulting in loosening or spalling of the surrounding rock.

[0022] S2: After the primary pillar 1 is laid, the joints and cracks in the upper and lower walls of the surrounding rock are sealed with concrete spraying. The slurry is pressed into the joints and cracks of the rock mass through the spraying pressure to enhance the bonding force between the rock masses.

[0023] In this step, the shotcrete layer forms a closed protective shell on the surface of the surrounding rock 2. This not only cements the broken rock mass into a whole, improving its integrity, but also effectively blocks the ingress of air and moisture, slowing the rate of weathering. Using shotcrete sealing measures can provide a planar support effect in areas with developed joints and fissures, forming an initial support shell and providing a good load-bearing foundation for subsequent support components.

[0024] S3, based on the surrounding rock 2 shotcreting treatment, first use cross bracing pillars to temporarily support the upper and lower surrounding rocks, and then on this basis, lay anchor rods in the upper and lower surrounding rocks for support, so as to improve the stress condition of the surrounding rock in the stope and prevent spalling.

[0025] In this step, the installation of the horizontal bracing provides initial stability for anchor bolt installation, effectively reducing the risk of surrounding rock 2 destabilization during mining. The subsequently installed anchor bolts 3 anchor the broken surrounding rock 2 and connect to the stable rock layer, forming a point-to-surface combined support structure. This pulls loose blocks into the stable structure, preventing the surrounding rock from loosening and collapsing. Furthermore, the anchor bolts 3 work in conjunction with the shotcrete layer to further enhance the surrounding rock's shear and pullout resistance, forming a three-dimensional stabilization system.

[0026] S4: For the unstable area with overhanging slabs, broken mud and cracks at the junction of surrounding rock 2 and ore vein, reinforced concrete beams are cast to replace the broken rock mass to form an alternative structural support.

[0027] In this step, reinforced concrete beams 4 are embedded with threaded steel bars 5 through pre-drilled holes and tied together to form a reinforcement structure 6, completing the concrete pouring and curing process. This structure replaces the original unstable rock mass and, by integrating with the surrounding rock mass 2, provides strong support for the fractured boundary. Reinforced concrete beams 4 not only physically fill the gap but also provide efficient load-bearing support through their rigid structural properties. This is particularly suitable for areas with severe weathering and muddiing at the ore-rock interface, effectively preventing the risk of roof collapse and spalling.

[0028] like Figure 2 As shown, three primary pillars are set: one at 1 / 3 of the stope's mining height and at 1 / 3 and 2 / 3 of its length, respectively; and another at 2 / 3 of its mining height and midway along its length. The primary pillars measure 4m x 4m. This dimension has been optimized through engineering to provide sufficient support strength to improve the stress state of the surrounding rock 2 while minimizing the need to occupy excessive mining space and impact resource recovery, thus ensuring a balanced balance between safety and mining economics. Furthermore, the number of primary pillars 1 can be flexibly adjusted based on the development and stability of the joints and fissures in the surrounding rock 2, to accommodate site requirements under varying geological conditions.

[0029] In some embodiments, the grouting and sealing treatment uses a PZ-5 type shotcrete machine to spray concrete, the concrete strength is C20, and the amount of accelerator is 5% of the cement amount. The use of the PZ-5 type shotcrete machine can achieve high-efficiency, high-pressure atomization spraying, ensuring that the concrete is evenly covered on the surface of the surrounding rock 2 and penetrates into the joints and fissures, effectively improving the bonding performance and density of the shotcrete layer. The C20 concrete has moderate strength and can avoid brittle failure while ensuring sufficient support force. The addition of the accelerator allows the concrete to quickly solidify in a short period of time, meeting the requirements for support reaction speed in the mining environment and preventing the shotcrete layer from falling off before the surrounding rock 2 continues to loosen. Specifically, the spraying thickness of the concrete is 50mm. This thickness setting can not only cover and seal the joints and fissures on the surface of the surrounding rock 2, but also will not cause delamination or construction difficulties due to the excessive thickness of the shotcrete layer. At the same time, it is also convenient for the subsequent anchor rods 3 and steel mesh to work together to form a multi-component composite support system, thereby improving the overall weathering and spalling resistance of the surrounding rock 2.

[0030] like Figure 4-5As shown, in some embodiments, the anchor rod 3 is a φ18mm left-handed threaded steel resin anchor rod with a length of 1.5-1.8m. During installation, the anchor rod 3 should be perpendicular to the surface of the surrounding rock, and the support plate should be close to the rock surface. The anchoring force should be no less than 50kN, and the tightening force should be no less than 100N·m. The anchor rod 3 is quickly solidified and fixed inside the surrounding rock 2 by resin anchoring, which can effectively anchor loose blocks and connect them with deep stable rock masses to form a force-bearing whole. The left-handed structure can enhance the bite force with the anchoring agent during the installation process and improve the anchoring efficiency. The anchor rod 3 is driven vertically during installation to ensure that its force direction is orthogonal to the rock surface, thereby improving its pull-out resistance. The support plate is close to the rock surface to prevent displacement and slippage. The anchoring force and tightening force parameters ensure that the anchor rod still has a stable bearing capacity under extreme stress conditions, effectively suppressing the shedding, spalling and collapse of the surrounding rock 2.

[0031] Furthermore, for areas with severe weathering and fragmentation, metal steel mesh is added on the basis of anchor rods 3 and shotcrete support. The steel mesh is covered on the surface of the surrounding rock 2 and connected with the anchor rods 3, which can provide surface constraint in a large range, further improving the integrity of the surrounding rock support, especially for areas with severe joint and fissure development. It has stronger wrapping and protection capabilities to prevent fragments from falling. Specifically, the steel mesh can be made of φ6.5mm steel bars, with a mesh size of 150mm×150mm and a mesh size of 1m×2m. It is firmly connected to the anchor rods 3 during laying. The setting of this structural parameter ensures that the mesh has sufficient strength and flexibility. Without increasing the weight of the support too much, it can adapt to the contour changes of the irregular surrounding rock 2 surface and form a stable coupling with the anchor rods 3, thereby improving the force uniformity and long-term stability of the anchor rod mesh combined support system.

[0032] like Figure 6 As shown, the rock mass at the junction of the surrounding rock 2 and the ore vein is broken, with overhanging slabs appearing in many places. The interface between the ore and rock is in a broken and muddy state, and the surrounding rock is unstable, posing a threat to the safety of personnel and equipment. In order to ensure safe mining, this embodiment uses the method of casting reinforced concrete beams 4 to replace the broken and unstable rock mass. Since there are weak interlayers and muddy structures between the surrounding rock 2 and the ore vein in this area, effective support cannot be achieved through traditional anchor rods 3 or grouting methods. Therefore, by arranging reinforced concrete beams 4 with a rigid structure at the interface, it can actively assume the function of stabilizing the surrounding rock structure and improve the support stiffness and safety level. Supporting by casting reinforced concrete beams 4 can effectively solve the prominent problems of broken muddy, overhanging slabs, unstable and unsafe surrounding rock at the interface of the ore and rock, and ensure the structural continuity and operational safety during the mining process of the mine.

[0033] like Figure 7 As shown, the pouring of reinforced concrete beam 4 includes the following construction steps: S41, steel bar drilling is arranged along both sides of the stope with a grid size of 30cm×25cm and a drilling depth of 1.2 meters. This drilling method ensures that the threaded steel bars 5 are evenly distributed in the surrounding rock 2, facilitating the subsequent formation of a reinforced concrete beam 4 with continuous structure and uniform stress. At the same time, it ensures that the drilling depth reaches the stable area of ​​the rock mass, which is conducive to enhancing the anchoring effect and the overall embedding force of the reinforced concrete beam 4.

[0034] S42, insert a 1.6-meter-long threaded steel bar 5 into the drill hole, with an exposed length of 0.4 meters. The steel bars are laid out and tied along the strike direction of the stope to form a reinforcement structure 6. After the threaded steel bars 5 penetrate deep into the surrounding rock 2, combined with the extension of the exposed section, a continuous tie system is formed. The reinforcement structure 6 formed by tying on its surface can provide skeleton support for the reinforced concrete beam 4, improve the overall stiffness and bearing capacity of the structure, and ensure good shear engagement between the beam and the surrounding rock.

[0035] S43, before pouring concrete, lay woven bags under the reinforced concrete beam 4 to prevent the concrete from bonding with the slag below; this step can effectively isolate the concrete from the residual slag at the bottom of the mine, avoid slurry leakage or interface delamination caused by mixing of concrete and loose media, thereby ensuring the integrity and molding quality of the lower edge structure of the reinforced concrete beam 4.

[0036] S44: Concrete is poured and cured for at least one week, with no mining operations performed during this period. This curing time ensures that the concrete reaches its design strength and stabilizes its initial shrinkage. Suspending mining during this period helps avoid structural disturbance and prevents premature load failure of reinforced concrete beam 4.

[0037] Furthermore, the thickness, width and length of the reinforced concrete beam 4 are determined according to the degree of surrounding rock fragmentation. The more severely the surrounding rock 2 is fragmented, the larger the structural size should be to improve the support capacity and coverage range; while in areas where the structure is relatively intact, the size can be reduced to save materials and construction space, thereby achieving a dynamic balance between support effect and construction efficiency.

[0038] In summary, the present invention discloses a method for supporting and reinforcing surrounding rocks during the mining process of steeply inclined, extremely thin, and difficult-to-mined ore bodies. The method includes analyzing the stress and displacement distribution of the mining site based on numerical simulation, laying out primary ore pillars 1 within the key height range of the mining site, forming a closed layer on the surface of the surrounding rock 2 by spraying concrete, combining anchor rods 3 with steel mesh to form a composite support system, and replacing and supporting unstable rock masses by pouring reinforced concrete beams 4 in areas with severe crushing and muddification, in conjunction with threaded steel bars 5 and reinforcement structures 6. The technical solution as a whole embodies a coordinated control mechanism of point support, surface closure, body anchoring, and rigid replacement, and has the advantages of high structural stability, strong adaptability to complex geological conditions, and good feasibility of construction technology. The present invention can significantly improve the stress concentration and surrounding rock instability problems of steeply inclined, extremely thin ore bodies during the mining process. By implementing differentiated coordinated support for different structural areas of the mining site, it effectively suppresses the loosening, weathering, spalling, and caving of the surrounding rocks, improves the recovery rate of ore resources and operational safety, and solves the technical bottleneck that traditional support methods are difficult to adapt to extremely thin, weathered, and crushed ore bodies. Compared to existing single support methods, this method offers greater support system integrity, wider adaptability, and greater scalability. It provides a practical solution for ore body stability control under complex geological conditions. It is particularly suitable for mining projects involving steeply inclined, extremely thin, and well-jointed and fissured difficult-to-mineralize ore bodies. It has significant engineering application value and promotional significance in areas such as safe mining, efficient resource utilization, and ground pressure disaster prevention and control.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions described in the above embodiments, or to make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for supporting and reinforcing surrounding rock during the mining process of a steeply inclined, extremely thin, and difficult-to-mine ore body, characterized in that: The steps include: S1, based on numerical simulation analysis of the stress and displacement evolution of the rock mass during the shallow hole ore retention method stope recovery process, determine the rock mass tensile stress concentration area and the maximum displacement occurrence area, identify the range of one-third to two-thirds of the stope height as the key support area with poor stability of the surrounding rock (2), and leave primary ore pillars (1) in the said key support area to support the upper and lower wall surrounding rock (2); S2, after the primary pillars (1) are laid out, the joints and fissures of the upper and lower wall surrounding rocks (2) are sealed by concrete spraying, and the slurry is pressed into the joints and fissures of the rock mass by the spraying pressure to enhance the bonding force between the rock masses; S3, on the basis of the spraying treatment of the surrounding rock (2), first use the cross bracing pillars to temporarily support the upper and lower surrounding rock, and then on the basis of the cross bracing pillars, lay anchor rods (3) on the upper and lower surrounding rock (2) to support, improve the stress condition of the surrounding rock (2) in the mining area and prevent spalling; S4: For unstable areas with overhanging slabs, broken mud and the like at the junction of the surrounding rock (2) and the ore vein, reinforced concrete beams (4) are cast to replace the broken rock mass and form an alternative structural support.

2. The surrounding rock support and reinforcement method according to claim 1, characterized in that: In step S1, three primary pillars (1) are provided, one at 1 / 3 of the stope height and at 1 / 3 and 2 / 3 of the stope length, and the other at 2 / 3 of the stope height and in the middle of the stope length.

3. The surrounding rock support and reinforcement method according to claim 2, characterized in that: The specification of the primary ore pillar (1) is 4m×4m.

4. The surrounding rock support and reinforcement method according to claim 1, characterized in that: In step S2, the spraying sealing treatment uses a PZ-5 type spraying machine to spray concrete, the concrete strength is C20, and the amount of accelerating agent used is 5% of the amount of cement.

5. The surrounding rock support and reinforcement method according to claim 4, characterized in that: The spraying thickness of the concrete is 50 mm.

6. The surrounding rock support and reinforcement method according to claim 1, characterized in that: In step S3, the anchor rod (3) is a φ18mm left-handed threaded steel resin anchor rod with a length of 1.5-1.8m. During installation, the anchor rod (3) should be perpendicular to the surface of the surrounding rock (2), and the support plate should be close to the rock surface. The anchoring force should be no less than 50kN, and the tightening force should be no less than 100N·m.

7. The surrounding rock support and reinforcement method according to claim 6, characterized in that: For areas with severe weathering and crushing, metal steel mesh is added on the basis of anchor rods (3) and shotcrete support.

8. The surrounding rock support and reinforcement method according to claim 7, characterized in that: The steel mesh is made of φ6.5mm steel bars, has a mesh size of 150mm×150mm, and a mesh size of 1m×2m. It is firmly connected to the anchor rods when laid.

9. The surrounding rock support and reinforcement method according to claim 1, characterized in that: In step S4, the pouring of the reinforced concrete beam (4) includes the following construction steps: S41, drilling steel bars along both sides of the stope with a grid size of 30 cm × 25 cm, the drilling depth of which is 1.2 meters; S42, inserting a 1.6-meter-long threaded steel bar (5) into the drill hole, with the exposed length of the threaded steel bar (5) being 0.4 meters, and laying and tying the steel bars along the strike direction of the stope to form a reinforcement structure (6); S43, before pouring concrete, woven bags are laid under the reinforced concrete beam (4) to prevent the concrete from bonding with the slag below; S44, pour concrete and maintain it for at least one week. No mining operations shall be carried out during the maintenance period.

10. The surrounding rock support and reinforcement method according to claim 9, characterized in that: The thickness, width and length of the reinforced concrete beam (4) are determined according to the degree of crushing of the surrounding rock.

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