Method for protecting brow line of large-diameter deep hole lateral caving bottom structure

Abstract

The invention provides a protection method for a large-diameter deep hole lateral caving bottom structure brow line, and belongs to the technical field of underground mine mining. According to the method, a continuous pre-crack is formed above the brow line in advance, crustal stress is actively released, impact of follow-up blasting on the brow line is reduced, and the structure of the brow line is effectively protected; then, a high-strength and high-toughness grouting material is used for conducting grouting reinforcement on the pre-crack and the peripheral rock mass crack development area, and the integrity and the deformation resistance of the brow line are improved; high-strength anchor rods and a reinforcing mesh are adopted to form an overall supporting structure, the stability of the brow line is further improved, displacement sensors and stress sensors are arranged in a stress concentration area, a deformation sensitive area and a potential damage area (near the brow line) of the brow line, the deformation amount and the stress distribution condition of the brow line are monitored, the deformation condition of the brow line is mastered in time, and the safety of the brow line is improved. The problems of crustal stress and blasting impact borne by the brow line are fundamentally solved, and mining safety is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of underground mining, and in particular to a method for protecting the eyebrow line of a bottom structure of a large-diameter deep hole lateral mine collapse. Background Art

[0002] Large-diameter deep hole lateral caving is an efficient and safe mining method, which is widely used in metal mining and is suitable for complex geological conditions such as thick and large ore bodies and steeply inclined ore bodies. This method arranges large-diameter deep holes at the bottom of the ore body and uses lateral caving to crush and recover the ore.

[0003] The eyebrow line is a key supporting structure between the bottom of the ore body and the goaf, and it is subjected to huge ground pressure and blasting shock. In practical applications, the protection of the eyebrow line of the bottom structure has become a key technical problem that restricts the further promotion of this method. First, with the increase of mining depth, the ground pressure increases significantly, and the eyebrow line is prone to deformation, cracking and even collapse. Second, the shock wave generated by large-diameter deep-hole blasting causes direct damage to the eyebrow line, affecting its stability. Third, there are usually natural cracks in the rock mass at the bottom of the ore body. After blasting, the cracks further expand, weakening the integrity of the eyebrow line.

[0004] In the prior art, most eyebrow line protection methods are passive protection, which cannot fundamentally solve the problem of stress concentration on the eyebrow line.

[0005] The patent application with the publication number CN116927824A discloses a pre-splitting and post-grouting reinforcement support structure and method for a harsh underground environment. The method first arranges pre-splitting holes and grouting holes vertically around the rock space in the harsh roof; a hole-protecting steel pipe with a single-side opening and an opening direction facing the rock space is placed in the hole, and a static fracturing agent is first injected into the pre-splitting hole to put the harsh roof in a critical crushing state; then cement-based materials are injected through the grouting hole to fill the rock cracks; after the slurry injection is completed, the pre-splitting hole and the grouting hole are blocked; the present invention actively strengthens the roof through human intervention, eliminates the instability factors in the roof, and makes the subsequent support work simple and convenient. This method effectively solves the problem that the roof pressure can only be passively accepted in the traditional support method, and avoids safety accidents caused by the uncertainty of the roof. However, this method only uses static fracturing agents to break the roof and then grouting, lacks special design for blasting impact, multi-structure collaborative support and intelligent monitoring functions, and cannot meet the special needs of long-term stability of the eyebrow line in a high-stress mining environment.

[0006] In view of this, it is necessary to design a method for protecting the eyebrow line of the bottom structure of large-diameter deep hole lateral mine collapse to solve the above problems. Summary of the invention

[0007] In view of the technical problems existing in the background art, the present application provides a method for protecting the brow line of the bottom structure of large-diameter deep-hole sidewise ore caving, which actively releases the in-situ stress by pre-forming a continuous pre-crack above the brow line, reduces the impact of subsequent blasting on the brow line, then uses high-strength grouting materials to grout and reinforce the pre-crack and the surrounding rock mass fissure development area, and further forms an integral support structure through anchor bolts and steel meshes to improve the stability of the brow line. Displacement sensors and stress sensors are arranged in the stress concentration area, deformation sensitive area and potential failure area (near the brow line) of the brow line to monitor the deformation amount and stress distribution of the brow line, fundamentally solving the problems of in-situ stress and blasting impact borne by the brow line and ensuring mining safety.

[0008] The present application provides a method for protecting the brow line of the bottom structure of large-diameter deep-hole sidewise ore caving, including the following steps: S1. At a position 1 - 1.5 m above the designed position of the brow line, pre-splitting holes are arranged along the trend of the brow line, and pre-splitting blasting is carried out using an uncoupled charge structure to form a pre-crack; wherein, the charge amount is 0.3 - 0.6 kg / m, and the sectional charging method is adopted, with the length of each section less than or equal to 2 m; S2. After pre-splitting blasting, grouting holes are arranged at a position 0.5 - 1.0 m on both sides of the pre-crack and along the direction of the pre-crack inside the brow line rock mass, and high-strength grouting materials are used to fill the pre-crack and the rock mass fissures to reinforce the brow line; S3. After grouting and reinforcement, an integral support structure is formed by anchor bolts and steel meshes to support the brow line; S4. After the support is completed, displacement sensors and stress sensors are arranged at a position 0.1 - 0.5 m above and below the designed position of the brow line, and the displacement sensors and stress sensors are signal-connected to a data acquisition system to monitor the deformation and stress conditions of the brow line in real time.

[0009] In the embodiment of the present application, the in-situ stress is actively released through pre-splitting blasting, fundamentally reducing the force on the brow line and solving the limitations of traditional passive protection methods. The uncoupled charge structure and sectional charging method are adopted to accurately control the blasting energy and avoid excessive damage to the brow line. Moreover, the pre-splitting blasting parameters can be flexibly adjusted according to the on-site geological conditions and are applicable to different mine environments.

[0010] As a further improvement of the present application, the pre-splitting holes are arranged as upward holes, and the pre-splitting holes form an angle of 10° - 30° with the horizontal plane.

[0011] As a further improvement of the present application, the spacing of the pre-splitting holes is 0.5 - 1.0 m, the hole diameter is 50 - 80 mm, and the hole depth is 1.2 - 1.5 times the height of the brow line.

[0012] As a further improvement of the present application, according to the different degrees of fissure development, the spacing of the grouting holes is controlled to be 0.5 - 1.5 m, the hole diameter is 50 - 80 mm, and the hole depth exceeds the end of the pre - crack by 1 - 2 m to ensure full - crack coverage.

[0013] As a further improvement of the present application, the grouting material is a cement - based composite material, whose compressive strength is greater than or equal to 50 MPa and tensile strength is greater than or equal to 5 MPa.

[0014] As a further improvement of the present application, in step S2, high - pressure grouting technology is adopted for grouting reinforcement, the grouting pressure is 1.0 - 2.0 MPa, and the grouting speed is 10 - 20 L / min.

[0015] Traditional grouting reinforcement methods usually use ordinary cement slurries, which have low compressive and tensile strengths and are difficult to effectively fill rock mass fissures and improve the integrity of the eyebrow line. In the embodiments of the present application, a cement - based composite material with high strength and high toughness is used to fill the pre - cracks and rock mass fissures through high - pressure grouting technology, significantly improving the integrity and deformation resistance ability of the eyebrow line.

[0016] As a further improvement of the present application, the bolt is a full - length bonded bolt, its diameter is 20 - 25 mm, its length is 3 - 5 m, and the spacing is 1.0 - 1.5 m.

[0017] As a further improvement of the present application, the diameter of the steel bars of the steel bar mesh is 8 - 12 mm, and the grid spacing is 100 - 150 mm.

[0018] Traditional support methods usually use single bolt support or steel bar mesh support, which are difficult to form an overall support structure and cannot effectively resist large - scale ground pressure and blasting impact. In the embodiments of the present application, the full - length bonded bolt is combined with the steel bar mesh to form an overall support structure, significantly improving the stability of the eyebrow line.

[0019] As a further improvement of the present application, in step S3, prestressed bolts are used for bolt support, and the prestress is 50% - 70% of the yield strength of the bolts. The use of prestressed bolts further improves the support effect.

[0020] As a further improvement of the present application, the steel bar mesh and the bolts are connected by welding or tying.

[0021] The beneficial effects of the present application are: The present application provides a method for protecting the brow line of the bottom structure in large-diameter deep-hole side blasting. This method actively releases the in-situ stress by pre-forming a continuous pre-crack above the brow line, reducing the impact of subsequent blasting on the brow line and effectively protecting the brow line structure. Then, a high-strength and high-toughness grouting material is used to grout and reinforce the pre-crack and the surrounding rock mass fissure development area to improve the integrity and deformation resistance of the brow line. Further, a high-strength bolt and a steel mesh are used to form an overall support structure to further improve the stability of the brow line. Displacement sensors and stress sensors are set at the stress concentration area, deformation sensitive area and potential failure area of the brow line (0.1 - 0.5 m above and below the designed position of the brow line) to monitor the deformation amount and stress distribution of the brow line, timely grasp the deformation situation of the brow line, fundamentally solve the problems of in-situ stress and blasting impact borne by the brow line, and ensure mining safety.

[0022] The present application adopts a systematic protection scheme of "pre-splitting blasting - high-pressure grouting - collaborative support - intelligent monitoring". After arranging parallel pre-splitting holes at a distance of 1.0 - 1.5 m above the brow line and using an uncoupled charging structure to accurately release the in-situ stress, high-pressure grouting is carried out to fill the fissures, and a spatial collaborative support system is formed with fully grouted bolts and steel meshes. Finally, dynamic early warning is realized through a real-time monitoring system to form a full-process active protection of "stress release - overall reinforcement - dynamic monitoring".

[0023] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specific embodiments of the present application are specifically given. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solution of the present application, the drawings used in the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is the layout drawing of the pre-splitting blasting for the brow line.

[0026] Figure 2 It is Figure 1 the front view of

[0027] Figure 3 It is Figure 1 the side view of

[0028] Figure 4 It is the schematic diagram of the grouting reinforcement for the brow line.

[0029] Figure 5is Figure 4 front view of

[0030] Figure 6 is Figure 4 side view of

[0031] Figure 7 is the layout drawing of the eyebrow line support structure.

[0032] Figure 8 is Figure 7 front view of

[0033] Figure 9 is Figure 7 side view of

[0034] Figure 10 is the layout drawing of the real-time monitoring system for the eyebrow line.

[0035] Figure 11 is the comprehensive layout drawing of the protection method for the eyebrow line of the bottom structure of large-diameter deep-hole side blasting in this application. Specific implementation manners

[0036] Hereinafter, embodiments of the technical solution of this application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of this application, and thus are only examples and cannot be used to limit the protection scope of this application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0038] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0039] In the prior art, the protection method for the eyebrow line usually adopts passive protection measures (such as reinforced concrete reinforcement or bolt support), and cannot fundamentally solve the problems of ground stress and blasting impact borne by the eyebrow line.

[0040] The present application provides a method for protecting the brow line of the bottom structure of large-diameter deep-hole side blasting. By pre-forming a continuous pre-crack above the brow line, the in-situ stress is actively released to reduce the impact of subsequent blasting on the brow line. Then, a high-strength grouting material is used to grout and reinforce the pre-crack and the area where rock mass fissures develop around it. An integral support structure is formed by bolts and wire meshes to further improve the stability of the brow line. Displacement sensors and stress sensors are set in the stress concentration area, deformation-sensitive area, and potential failure area (near the brow line) of the brow line to monitor the deformation amount and stress distribution of the brow line, fundamentally solving the problems of in-situ stress and blasting impact borne by the brow line and ensuring mining safety.

[0041] Please refer to Figures 1 to 11 As shown in the figure, the embodiment of the present application provides a method for protecting the brow line of the bottom structure of large-diameter deep-hole side blasting, including the following steps: S1. At a position 1 - 1.5 m above the designed position of the brow line 1, pre-splitting holes 2 are arranged along the trend of the brow line 1, and pre-splitting blasting is carried out using a decoupled charging structure to form a pre-crack 31. Among them, the charge amount is 0.3 - 0.6 kg / m, and the sectional charging method is adopted, with the length of each section less than or equal to 2 m to control the blasting energy and avoid excessive damage to the brow line, as Figures 1 to 3 shown; Among them, the pre-splitting holes 2 are arranged as upward holes. The upward holes can better control the formation direction of the pre-crack 31, make the pre-crack 31 extend along the upper part of the brow line 1, and effectively release the in-situ stress above the brow line 1. The rock debris and crushed stones generated after blasting are easier to clean, reducing the secondary damage to the brow line.

[0042] Specifically, the angle of the upward holes is designed according to the geometric shape of the brow line and the in-situ stress distribution. In the embodiment of the present application, the pre-splitting holes 2 form an angle of 10° - 30° with the horizontal plane. If the angle is too small, the pre-crack may not be able to fully release the in-situ stress, and if the angle is too large, the construction difficulty may increase.

[0043] In the embodiment of the present application, the spacing of the pre-splitting holes 2 is 0.5 - 1.0 m, and the hole diameter is 50 - 80 mm.

[0044] The hole depth of the pre-splitting holes 2 is 1.2 - 1.5 times the height of the brow line to ensure that the pre-crack 31 can fully extend above the brow line 1.

[0045] S2. After pre-splitting blasting, grouting holes 43 are arranged at a position 0.5 - 1.0 m on both sides of the pre-crack and along the direction of the pre-crack inside the brow line rock mass, and a high-strength grouting material is used to fill the pre-crack 31 and the rock mass fissures to form a filled pre-crack 33 and filled fissures 32 to reinforce the brow line, as Figures 4 to 6 shown.

[0046] In the embodiments of the present application, according to different degrees of fissure development, the spacing of the grouting holes 43 is controlled to be 0.5 - 1.5 m, the hole diameter is 50 - 80 mm, and the hole depth exceeds the end of the pre - crack by 1 - 2 m to ensure full - crack coverage.

[0047] Among them, the grouting material is a cement - based composite material, whose compressive strength is not less than 50 MPa and tensile strength is not less than 5 MPa.

[0048] In the embodiments of the present application, the grouting material is injected into the grouting holes 43 through a grouting pipeline 42 connected to a grouting pump 41. The grouting reinforcement adopts a high - pressure grouting process, the grouting pressure is 1.0 - 2.0 MPa, and the grouting speed is 10 - 20 L / min. After grouting, the integrity of the rock mass is significantly improved, and the anti - deformation ability of the brow line is enhanced.

[0049] S3, after grouting reinforcement, an integral support structure is formed by bolts 51 and a steel mesh 52 to support the brow line; the steel mesh 52 and the bolts 51 are connected by welding or tying to form an integral support structure, as Figures 7 to 9 shown.

[0050] Among them, the bolts 51 are full - length bonded bolts, with a diameter of 20 - 25 mm, a length of 3 - 5 m, and a spacing of 1.0 - 1.5 m. The steel bars of the steel mesh 52 have a diameter of 8 - 12 mm, and the grid spacing is 100 - 150 mm.

[0051] The bolt support adopts prestressed bolts, and the prestress is 50% - 70% of the yield strength of the bolts 51.

[0052] S4, after the support is completed, sensors 61 are set in the stress concentration area, deformation - sensitive area, and potential failure area (near the brow line) of the brow line. The sensors 61 include displacement sensors and stress sensors. The displacement sensors and stress sensors are signal - connected to a data acquisition system to monitor the deformation and stress conditions of the brow line in real - time, as Figures 10 to 11 shown.

[0053] The stress concentration area, deformation - sensitive area, and potential failure area of the brow line refer to the areas 0.1 - 0.5 m above and below the designed position of the brow line.

[0054] Specifically, displacement sensors (such as LVDT linear displacement gauges) and stress sensors (such as vibrating wire stress gauges) arranged in the stress concentration area, deformation sensitive area, and potential failure area of the brow line are connected to the explosion-proof data acquisition instrument 62 through armored cables. The data acquisition instrument obtains sensor signals in real time at a sampling frequency of 1 - 10 Hz, and after A / D conversion, transmits the data to the surface monitoring center 63 through the network. The SCADA system of the surface monitoring center filters and normalizes the data, and uses the threshold analysis method (such as setting the displacement alarm threshold to 5 mm and the stress threshold to 80% of the rock mass strength) to achieve automatic early warning. At the same time, it predicts the deformation trend through time series analysis. All data is stored in the cloud database at 1-minute intervals for subsequent retrospective analysis and further optimization of parameters. In this way, the state of the brow line is grasped in real time through the intelligent monitoring system, solving the problem of lag in traditional manual inspections.

[0055] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application.

[0056] Embodiment 1 A certain iron mine uses the large-diameter deep-hole sidewise ore caving method for mining. The thickness of the ore body is 50 m and the dip angle is 60°. Due to the large ground pressure at the bottom of the ore body, the brow line is prone to deformation and damage. The protection method for the brow line of the large-diameter deep-hole sidewise ore caving bottom structure of the present invention is used to protect the brow line, and the specific steps are as follows: Pre-splitting blasting of the brow line: 1 m above the designed position of the brow line 1, pre-splitting holes 2 are arranged along the trend of the brow line 1, the hole spacing is 0.8 m, the hole diameter is 60 mm, and the hole depth is 6 m. The pre-splitting blasting is carried out using an uncoupled charging structure, and the charge amount is 0.5 kg / m.

[0057] Reinforcement of the brow line: After the pre-splitting blasting, grouting holes 43 are arranged at 0.5 - 1.0 m on both sides of the pre-splitting crack and along the direction of the pre-splitting crack inside the brow line rock mass. The brow line is grouted and reinforced using a cement-based composite material with a compressive strength of 60 MPa and a tensile strength of 6 MPa, and the grouting pressure is 1.5 MPa.

[0058] Support of the brow line: After the grouting reinforcement, the brow line is supported using fully grouted bolts 51 with a diameter of 22 mm and a length of 4 m, and the spacing of the bolts 51 is 1.2 m. At the same time, the brow line is supported using a steel mesh 52 with a diameter of 10 mm and a mesh spacing of 120 mm, and the steel mesh 52 is connected to the bolts 51 to form an integral support structure.

[0059] Monitoring of the brow line: After the completion of the brow line protection construction, displacement sensors and stress sensors are set in the stress concentration area, deformation sensitive area, and potential failure area (near the brow line) of the brow line to monitor the deformation, stress, etc. of the brow line in real time.

[0060] After more than one year of production practice, the brow line has not shown obvious deformation or damage, effectively ensuring the safety and efficiency of mining.

[0061] Example 2 A certain copper mine adopts the large-diameter deep-hole side caving method for mining. The thickness of the ore body is 40m, and the dip angle is 70°. Due to the relatively large ground pressure at the bottom of the ore body, the brow line is prone to deformation and damage. The method of the present invention is used to protect the brow line, and the specific steps are as follows: Pre-splitting blasting of the brow line: At a position 1.2m above the designed position of the brow line 1, pre-splitting holes 2 are arranged along the trend of the brow line 1. The hole spacing is 0.6m, the hole diameter is 70mm, and the hole depth is 5m. The pre-splitting blasting is carried out using an uncoupled charge structure, and the charge amount is 0.4kg / m.

[0062] Reinforcement of the brow line: After the pre-splitting blasting, grouting holes 43 are arranged at a distance of 0.5 - 1.0m on both sides of the pre-splitting crack and along the direction of the pre-splitting crack inside the brow line rock mass. A cement-based composite material with a compressive strength of 55MPa and a tensile strength of 5.5MPa is used to grout and reinforce the brow line, and the grouting pressure is 1.8MPa.

[0063] Support of the brow line: After the grouting reinforcement, a full-length bonded bolt with a diameter of 25mm and a length of 5m is used to support the brow line, and the bolt spacing is 1.0m. At the same time, a steel mesh with a diameter of 12mm and a grid spacing of 100mm is used to support the brow line, and the steel mesh is connected to the bolts to form an integral support structure.

[0064] Monitoring of the brow line: After the construction of the brow line protection is completed, displacement sensors and stress sensors are set in the stress concentration area, deformation sensitive area and potential damage area (near the brow line) of the brow line to monitor the deformation, stress, etc. of the brow line in real time.

[0065] After more than one year of production practice, the brow line has not shown obvious deformation or damage, effectively ensuring the safety and efficiency of mining.

[0066] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same structure and the same function and effect as the technical idea within the scope of the technical solution of this application are all included in the technical scope of this application. In addition, within the scope of not departing from the main idea of this application, various deformations that can be thought of by those skilled in the art are applied to the embodiments, and other methods constructed by combining some constituent elements of the embodiments are also included in the scope of this application.

Claims

1. A method for protecting the brow line of the bottom structure of large-diameter deep-hole side casting mining, characterized in that, It includes the following steps: S1. At a position 1 - 1.5 m above the designed position of the eyebrow line, arrange pre-splitting holes along the trend of the eyebrow line, and conduct pre-splitting blasting with an uncoupled charge structure to form a pre-split crack; among them, the charge amount is 0.3 - 0.6 kg / m, and the sectional charging method is adopted, with the length of each section less than or equal to 2 m; S2. After pre-splitting blasting, arrange grouting holes at a position 0.5 - 1.0 m on both sides of the pre-split crack and inside the rock mass of the eyebrow line along the direction of the pre-split crack, and use high-strength grouting materials to fill the pre-split crack and rock mass fissures to reinforce the eyebrow line; S3. After grouting reinforcement, use anchor bolts and wire meshes to form an integral support structure to support the eyebrow line; S4. After the support is completed, set displacement sensors and stress sensors at positions 0.1 - 0.5 m above and below the designed position of the eyebrow line. The displacement sensors and stress sensors are signal-connected to a data acquisition system to monitor the deformation and stress conditions of the eyebrow line in real time.

2. The protection method of the brow line of the bottom structure for lateral ore caving in large-diameter deep holes according to claim 1, characterized in that The pre-splitting holes are arranged as upward blast holes, and the pre-splitting holes form an angle of 10° - 30° with the horizontal plane.

3. The method for protecting the brow line of the bottom structure of side caving in large-diameter deep holes according to claim 1, characterized in that The spacing of the pre-splitting holes is 0.5 - 1.0 m, the hole diameter is 50 - 80 mm, and the hole depth is 1.2 - 1.5 times the height of the eyebrow line.

4. The method for protecting the brow line of the bottom structure of sidewise ore caving in large-diameter deep holes according to claim 1, characterized in that, The spacing of the grouting holes is 0.5 - 1.5 m, the hole diameter is 50 - 80 mm, and the hole depth exceeds the end of the pre-split crack by 1 - 2 m.

5. The protection method for the brow line of the bottom structure of large-diameter deep-hole sidewise ore caving according to claim 1, characterized in that, The grouting material is a cement-based composite material, whose compressive strength is greater than or equal to 50 MPa and tensile strength is greater than or equal to 5 MPa.

6. The protection method for the brow line of the bottom structure of large-diameter deep-hole sidewise ore caving according to claim 1, characterized in that The anchor bolts are full-length bonded anchor bolts, with a diameter of 20 - 25 mm, a length of 3 - 5 m, and a spacing of 1.0 - 1.5 m.

7. The protection method for the brow line of the bottom structure of large-diameter deep-hole side caving according to claim 1, characterized in that, The steel bars of the wire mesh have a diameter of 8 - 12 mm, and the grid spacing is 100 - 150 mm.

8. The protection method for the brow line of the bottom structure of large-diameter deep-hole sidewise ore caving according to claim 1, characterized in that In step S2, high-pressure grouting technology is adopted for grouting reinforcement, the grouting pressure is 1.0 - 2.0 MPa, and the grouting speed is 10 - 20 L / min.

9. The protection method for the brow line of the bottom structure of large-diameter deep-hole side caving according to claim 1, characterized in that In step S3, prestressed anchor bolts are used for anchor bolt support, and the prestress is 50% - 70% of the yield strength of the anchor bolts.

10. The protection method for the brow line of the bottom structure of large-diameter deep-hole side caving according to claim 1, characterized in that The wire mesh and the anchor bolts are connected by welding or tying.

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