A method for constructing a distributed rigid-flexible coupling bottom structure

Abstract

The application discloses a distributed rigid-flexible coupling bottom structure construction method, and belongs to the technical field of mine engineering. The stress transmission path of rock mass is actively cut off through pre-splitting space, and the continuous bottom structure is divided into independent units, so that the problems of maximum principal stress concentration and blast vibration accumulation and conduction are solved. On the other hand, the step-by-step stoping is matched with the formation of peach-shaped pillars, the formed filling body is combined with double retaining walls, the rigid pillar bearing structure is formed, the rigid-flexible coupling system is formed by the flexible interval unloading of the pre-splitting space, the structure deformation caused by the settlement of the filling body is resisted, local damage chain diffusion is avoided, and the problems that the bottom structure of the super-large scale panel is easy to be disturbed and production is easy to be interrupted in the traditional method are solved.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering technology, and in particular relates to a method for constructing a distributed rigid-flexible coupled bottom structure. Background Technology

[0002] In recent years, with the increased efforts in the development of deep mineral resources, the number of mines with extra-large and thick ore bodies has continued to increase. The scale of mine infrastructure and production has expanded in tandem. Combined with the ore body occurrence conditions, the size of the mining panel of such mines often exceeds 200 meters × 200 meters, forming ultra-large-scale mining units.

[0003] In this type of panel mining, the bottom structure of the roadway needs to be constructed in advance before the mining operation, and it continuously bears the dual core load throughout the mining cycle. It is easily disturbed during the production process, which can lead to structural instability and affect production efficiency. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a method for constructing a distributed rigid-flexible coupled bottom structure, including:

[0005] Preparatory work is carried out in the bottom structure of the ultra-large-scale panel area;

[0006] In the bottom structure of the ultra-large-scale panel, pre-splitting blast holes are arranged at intervals along the strike of the body to be mined.

[0007] Pre-splitting blasting is carried out to form a pre-splitting space, which is located within a peach-shaped pillar, and the two peach-shaped pillars containing the pre-splitting space are not adjacent.

[0008] The first-stage mining area is back-mined, and an inclined surface on one side of the peach-shaped pillar is formed in the ore body by means of construction inclined holes and blasting.

[0009] An arched filling retaining wall is constructed at the pre-fractured space that has been formed in the peach-shaped pillar ore roadway. At the same time, an additional retaining wall is set at the intersection of the ore roadways of the first and second step mining areas, and then the goaf of the first step mining area is filled.

[0010] After the filling material in the first-stage stope reaches the designed strength and is fully consolidated, the second-stage stope mining operation is carried out. Similarly, the inclined surface on the other side of the peach-shaped pillar is formed by constructing inclined holes and blasting, thus forming the peach-shaped pillar.

[0011] In some embodiments, the preparation project includes, on the basis of the development projects such as the upper plate haulage roadway, the lower plate haulage roadway, and the plate cross-vein roadway, the ore receiving roadway, the ore exit roadway, and the ore exit access roadway are constructed in sequence to form a complete bottom structure engineering system of the plate.

[0012] In some implementations, the cross-sectional dimensions of the receiving tunnel, the exit tunnel, and the exit access road need to meet the requirements for ore extraction and ventilation, and provide operating space for subsequent pre-splitting blasting operations.

[0013] In some embodiments, the pre-splitting blast holes are arranged along the extension direction of the ore exit roadway of the bottom structure, and a buffer layer is reserved between the bottom of the pre-splitting blast holes and the boundary of the bottom structure; the buffer layer is used to avoid damage to the main body of the bottom structure caused by the pre-splitting blasting, so as to accurately control the blasting influence range.

[0014] In some embodiments, the pre-splitting blasting employs an interleaved, uncoupled charge structure.

[0015] In some implementations, during the first-step mining operation, upward fan-shaped medium-deep holes are constructed in the upper section of the rock-drilling roadway and the bottom ore-receiving roadway of the mining area, while inclined short blast holes are constructed near the boundary of the mining area in the ore-receiving roadway; the inclined short blast holes are used to form ore chutes to improve ore flowability and ore extraction efficiency.

[0016] In some implementations, the blasting for one-step mining operations employs a medium-deep hole sequential micro-differential detonation method.

[0017] In some implementations, a preset number of boreholes are detonated each time, with the boreholes within a row being detonated in at least two separate stages according to a slight time delay, and delayed blasting is used between rows.

[0018] In some implementations, while constructing the arched filling retaining wall, an additional retaining wall is set up in the section where the receiving roadway of the first-stage mining area and the second-stage mining area intersects.

[0019] In some implementations, during the two-step stope mining, the arrangement logic of the upward fan-shaped medium-deep holes and the inclined short blast holes used to form the ore drop trough is consistent with that of the one-step stope; and when the inclined holes are used to form the other inclined surface of the peach-shaped ore pillar, the construction direction of the inclined holes is adapted to the inclined holes used to form the other inclined surface of the peach-shaped ore pillar in the one-step stope.

[0020] This application provides a method for constructing a distributed rigid-flexible coupled bottom structure, including:

[0021] Preparatory work is carried out in the bottom structure of the ultra-large-scale panel area;

[0022] In the bottom structure of the ultra-large-scale panel, pre-splitting blast holes are arranged at intervals along the strike of the body to be mined.

[0023] Pre-splitting blasting is performed to create a pre-splitting space;

[0024] The first-stage mining area is back-mined, and an inclined surface on one side of the peach-shaped pillar is formed in the ore body by means of construction inclined holes and blasting.

[0025] An arched filling retaining wall is constructed at the pre-fractured space that has been formed in the peach-shaped pillar ore roadway. At the same time, an additional retaining wall is set at the intersection of the ore roadways of the first and second step mining areas, and then the goaf of the first step mining area is filled.

[0026] After the filling material in the first-stage stope reaches the designed strength and is fully consolidated, the second-stage stope mining operation is carried out. Similarly, the inclined surface on the other side of the peach-shaped pillar is formed by constructing inclined holes and blasting, thus forming the peach-shaped pillar.

[0027] By actively cutting off the stress transmission path of the rock mass through pre-splitting space, the continuous bottom structure is divided into independent units, thereby solving the problems of maximum principal stress concentration and cumulative transmission of blasting vibration. On the other hand, the step-by-step mining combined with the formation of peach-shaped pillars, combined with the filling body formed by double retaining walls, forms a rigid pillar bearing structure. Combined with the flexible interval unloading of the pre-splitting space, a rigid-flexible coupling system is formed, which not only resists the structural deformation caused by the settlement of the filling body, but also avoids the chain diffusion of local damage. This specifically solves the core problems of easy disturbance of the bottom structure and easy interruption of production in traditional methods. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall layout of the bottom structure of a large-scale panel area and the preparation project of a distributed rigid-flexible coupling bottom structure construction method provided in the embodiments of this application;

[0029] Figure 2 This is a schematic diagram of the pre-splitting borehole arrangement and the bottom structure after the pre-splitting space is formed, according to a distributed rigid-flexible coupling bottom structure construction method provided in this application embodiment.

[0030] Figure 3 This is a top-down view of the filling operation within the pre-cracked space, illustrating a distributed rigid-flexible coupling bottom structure construction method provided in this application embodiment.

[0031] Figure 4 This is a schematic diagram of a step in the mining blasting operation within a stope, as provided in an embodiment of this application, of a distributed rigid-flexible coupling bottom structure construction method.

[0032] Figure 5 This is a schematic diagram of a step in the construction of a distributed rigid-flexible coupled bottom structure provided in this application embodiment, as well as the filling work in the pre-fractured space of the peach-shaped pillar.

[0033] Explanation of reference numerals in the attached diagrams: 1. Panel pass; 2. Upper hanging wall haulage roadway; 3. Ore extraction access road; 4. Ore extraction roadway; 5. Backfill retaining wall; 6. Return air shaft; 7. Peach-shaped pillar; 8. Pre-splitting space; 9. Pre-splitting blast hole; 10. Arched backfill retaining wall; 11. Panel pillar; 12. External connecting roadway; 13. Stope to be mined; 14. Ore to be extracted; 15. Backfill body; 16. Lower hanging wall haulage roadway; 17. Panel cross-vein connecting roadway; 18. Step 19. Mining roadway in the first-stage stope; 20. Mining roadway in the second-stage stope; 21. Mining roadway in the second-stage stope; 22. Bottom structure; 23. Upward fan-shaped blast hole; 24. Segmented rock drilling roadway; 25. Second-stage stope awaiting return mining; 26. Inclined hole forming peach-shaped pillar; 27. Drainage trough; 28. Filling body in the first-stage stope; 30. Filling body in the pre-splitting space; 31. Filling retaining wall in the second-stage mining roadway; 32. Bottom filling body. Detailed Implementation

[0034] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0036] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0039] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0040] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0041] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] In recent years, with the increased efforts in the development of deep mineral resources, the number of mines with extra-large and thick ore bodies has continued to increase. The scale of mine infrastructure and production has expanded in tandem. Combined with the ore body occurrence conditions, the size of the mining panel of such mines often exceeds 200 meters × 200 meters, forming ultra-large-scale mining units.

[0044] In this type of panel mining, the roadway engineering of the bottom structure needs to be constructed in advance before the mining operation, and it will continuously bear dual core loads throughout the mining cycle: On the one hand, the cyclic blasting vibration during the mining process will be transmitted through the interconnected roadway network, causing the vibration energy to accumulate continuously inside the structure, especially causing superimposed disturbance to the bottom structure of the end mining section, exacerbating the risk of damage; on the other hand, due to the limitations of the existing filling technology, the lower filling body is difficult to fully connect with the roof and has a natural shrinkage rate, which can easily cause the top filling body to settle, thereby causing the bottom structure to settle and deform, affecting the structural integrity.

[0045] Meanwhile, to maintain the stability of the long sidewalls of the stope, the long side direction is usually aligned with the direction of the maximum principal stress. However, this arrangement requires the bottom structure to extend perpendicular to the direction of the maximum principal stress, resulting in significant stress concentration on the bottom structure and further increasing the probability of structural failure. More importantly, the bottom structure of ultra-large-scale panels is designed as a single, interconnected structure. Local structural damage caused by the aforementioned problems such as accumulated blasting vibrations, stress concentration, and settlement deformation of the backfill can be rapidly transmitted and spread across regions through connecting roadways. This not only reduces the ore extraction efficiency in the damaged area but also endangers the bottom structure of adjacent stopes, drastically increasing the difficulty of bottom structure repair and even causing a complete interruption of production across the entire panel.

[0046] Therefore, how to solve the problem of insufficient stability of the bottom structure of ultra-large-scale mining areas under complex stress and multi-factor coupling, as well as the problem of chain-like diffusion of local damage, has become an issue to ensure the safe and efficient mining of deep mines.

[0047] To address the above technical issues, this application provides a method for constructing a distributed rigid-flexible coupled bottom structure, referring to... Figures 1 to 5 ,include:

[0048] S10. Arrange the preparatory works in the bottom structure of the ultra-large panel. The purpose of this step is to build the basic engineering system for subsequent mining operations, such as development roadways, stope connecting roadways, ore receiving roadways, and ore exit roadways, to provide access for subsequent pre-splitting blast hole construction, stope mining, ore transportation, and personnel and equipment passage, and to clarify the boundaries of the first and second step stopes, and to plan the spatial range for step-by-step mining. At the same time, establish auxiliary systems such as ventilation, drainage, and power supply in advance to ensure the continuity and safety of subsequent operations.

[0049] For example, the upper plate haulage roadway 2 and the lower plate haulage roadway 16 in the middle section of the construction section serve as the main channels for ore transportation and personnel and equipment passage in the panel area; at the same time, the construction panel cross-vein connecting roadway 17 connects the upper and lower plate haulage roadways to form a horizontal connecting network in the panel area and clearly define the overall boundary of the panel area.

[0050] Based on the development project, the receiving roadway 18 of the first-stage stope and the receiving roadway 20 of the second-stage stope were constructed in sequence to receive ore from the stope; the ore exit roadway 4 was constructed simultaneously as a channel for ore transfer; then the ore exit access roadway 19 of the first-stage stope and the ore exit access roadway 21 of the second-stage stope were constructed to connect the receiving roadway and the ore exit roadway, forming an ore transfer path; in addition, the external connection roadway 12 was constructed to realize personnel, equipment and ventilation communication between different stopes.

[0051] Construction of panel chute 1 connects the ore extraction roadway with the external transportation system, improving ore transfer efficiency; construction of return air shaft 6, in conjunction with the transport roadway along the vein and the external connecting roadway, constructs a ventilation system; at the same time, drainage pipes, power supply lines and other supporting facilities are laid out, working in synergy with the roadway engineering to form a complete panel bottom structure engineering system, meeting the needs of subsequent pre-splitting blasting, mining backfilling and other operations.

[0052] S20. In the bottom structure of the ultra-large-scale panel, pre-splitting blast holes are arranged at intervals along the strike of the ore body. The purpose of this step is to pre-set the hole positions for controllable pre-splitting blasting, so as to ensure that the pre-splitting space can be formed in an intermittent distribution in the strike of the ore body, which is conducive to dividing the overall peach-shaped ore pillar into multiple independent units.

[0053] For example, holes are arranged along the extension direction of the ore passage 4 inside the bottom structure 22 to ensure that the orientation of the pre-splitting blast holes 9 is consistent with the orientation of the ore body to be mined, thus laying the foundation for the subsequent formation of pre-splitting spaces 8 distributed along the orientation of the ore body.

[0054] In the ore body area between the receiving roadway 18 of the first-step stope and the receiving roadway 20 of the second-step stope, pre-splitting blast holes 9 are sequentially arranged according to the interval requirements. This area is the formation range of the subsequent peach-shaped pillar 7. The interval arrangement of the holes can be used to plan the pillar segmentation unit in advance.

[0055] When drilling, avoid the ore exit roadway 19 of the first-step stope, the ore exit roadway 21 of the second-step stope, and the core bearing section of the receiving roadway to ensure that the position of the pre-splitting blast hole 9 does not affect the main stability of the bottom structure 22, while reserving safe operating space for subsequent pre-splitting blasting.

[0056] Each pre-splitting blast hole 9 corresponds to the central area of ​​the pre-splitting space 8 to be formed later, ensuring that the pre-splitting space is accurately formed after blasting, and making the hole positions preset for the subsequent division of the overall peach-shaped ore pillar.

[0057] S30. Perform pre-splitting blasting to create a pre-splitting space within a peach-shaped pillar. The two peach-shaped pillars containing the pre-splitting space are not adjacent. This step aims to cut off the stress transmission path of the rock mass by creating a pre-splitting space that severs the continuous ore body, thus achieving physical segmentation of the pillar area in advance. This prevents the stress from the surrounding rock mass from being transmitted to the subsequent peach-shaped pillar area, avoiding instability and failure of the pillar due to stress concentration.

[0058] For example, staggered uncoupled charges are used in the pre-splitting boreholes 9 to ensure that the explosive energy is evenly transferred to the rock mass of the borehole wall, while avoiding excessive blasting impact due to overly dense charges, thus protecting the main components of the bottom structure 22, such as the ore outlet roadway 4 and the ore receiving roadway, from damage.

[0059] Based on the interval distribution of pre-splitting boreholes 9, the detonation operation is initiated in batches. Each batch detonates 1-2 adjacent pre-splitting boreholes 9 to ensure that the blasting energy is concentrated on the rock mass at the current borehole position, accurately forming an independent pre-splitting space 8, and avoiding excessive rock mass fragmentation caused by simultaneous detonation of multiple boreholes.

[0060] During the blasting process, the buffer layer at the boundary between the bottom of the pre-splitting blast hole 9 and the bottom structure 22 is strictly controlled to ensure that the blasting only forms the pre-splitting space 8 in the area to be oreed, without affecting the bearing sections of the first-step mining roadway 18 and the second-step mining roadway 20, thus maintaining the overall stability of the bottom structure.

[0061] Through the above blasting operation, pre-splitting spaces 8 are formed one by one at the positions of the pre-splitting blast holes 9 along the direction of the ore body. Each pre-splitting space 8 is distributed at a preset interval in the area where the subsequent peach-shaped ore pillar 7 is formed, thereby realizing the physical cutting of the continuous ore body and providing a spatial basis for the subsequent division of the peach-shaped ore pillar 7 into independent units.

[0062] S40. The first step of mining is to mine the mining area and form the inclined face of one side of the peach-shaped pillar by means of construction of inclined holes and blasting in the ore body; as the first stage of step mining, part of the ore body is mined first to realize resource recovery, and the inclined face of one side of the peach-shaped pillar is formed by means of inclined hole blasting.

[0063] For example, taking the first-step mining roadway 18 as the bottom working benchmark, the segmented drilling roadway 24 is used as the drilling operation channel to ensure that personnel and equipment can enter the working area through the external connecting roadway 12, while the return air shaft 6 ensures the ventilation of the mining area and provides a safe working environment for mining blasting.

[0064] In the segmented rock drilling tunnel 24, upward fan-shaped blast holes 23 are constructed to cover the ore body area to be mined in the first-stage mining area; after blasting, the ore falls into the receiving tunnel 18 of the first-stage mining area by its own gravity, and is then transferred to the ore exit tunnel 4 through the ore exit roadway 19 of the first-stage mining area, thus completing the ore recovery of the first-stage mining area.

[0065] In the first-step stope, near the boundary of the subsequent peach-shaped pillar 7, inclined holes 26 are constructed along a preset inclination angle to form the peach-shaped pillar. After the inclined holes are constructed, directional blasting is carried out. After the blasting, an inclined surface that matches the contour of one side of the peach-shaped pillar 7 is formed in the ore body. At the same time, in the area of ​​the receiving roadway 18 in the first-step stope adjacent to the inclined surface, inclined short blast holes are constructed to form a ore drop trough 27 to ensure that the subsequent ore can flow smoothly into the receiving roadway.

[0066] S50. Construct an arched backfilling retaining wall at the pre-fractured space already formed in the peach-shaped pillar ore exit roadway. At the same time, set up an additional retaining wall at the intersection of the ore receiving roadways of the first and second step stopes, and then backfill the goaf of the first step stope. The peach-shaped pillar ore exit roadway is maintained by the backfilling retaining wall, so that slurry can be placed to invade the peach-shaped pillar ore exit roadway through the gaps in the pre-fractured space during the backfilling operation, and form a spaced backfilling cushion layer in the peach-shaped pillar.

[0067] For example, at the pre-splitting space 8 in the mine roadway 4 corresponding to the peach-shaped pillar 7, an arched filling retaining wall 10 is built to ensure that the retaining wall completely covers the opening area of ​​the pre-splitting space 8, blocking the subsequent filling slurry from intruding into the mine roadway 4 through the gaps in the pre-splitting space 8. At the same time, the arched structure is used to enhance the impact resistance of the retaining wall itself and adapt to the filling pressure.

[0068] At the intersection of the first-stage mining roadway 18 and the second-stage mining roadway 20, a second-stage mining roadway filling retaining wall 31 (additional retaining wall) is installed to form double protection, preventing the filling slurry from overflowing from the intersection gap of the two mining roadways, while protecting the structural integrity of the roadway in the intersection section.

[0069] Through segmented drilling tunnel 24 or dedicated filling pipeline, filling material is injected into the goaf formed after the first-stage stope is mined until the top surface of the filling body is flush with the stope roof, forming the first-stage stope filling body 28; during the filling process, the sealing of the retaining wall is monitored to ensure that the slurry does not leak into the ore exit tunnel 4 or the second-stage stope area, and finally, under the synergistic effect of the pre-splitting space 8 and the retaining wall, a spaced filling body cushion layer is formed in the peach-shaped pillar 7.

[0070] S60. After the backfill material in the first-stage stope reaches the design strength and is fully consolidated, the second-stage stope mining operation is carried out. Similarly, the inclined surface on the other side of the peach-shaped pillar is formed by constructing inclined holes and blasting, thus creating the peach-shaped pillar. Pre-splitting spaces at intervals divide the continuous bottom structure into multiple independent units, forming a distributed pillar group. This avoids excessive stress on a single pillar leading to overall failure. Each unit is independently supported, further enhancing the overall stability of the bottom structure.

[0071] For example, the strength of the first-step stope backfill 28 is verified by testing equipment. After it meets the design requirements and is fully consolidated, the second-step stope mining preparation is started to ensure that subsequent operations do not damage the formed backfill and retaining wall structure.

[0072] Using the receiving roadway 20 of the second-step stope as the operating benchmark, upward fan-shaped blast holes 23 (with the same layout logic as the first-step stope) are constructed in the segmented rock drilling roadway 24 to cover the ore body area of ​​the second-step stope to be mined 25. After blasting, the ore is transferred to the ore exit roadway 4 through the receiving roadway 20 and the ore exit roadway 21 of the second-step stope, thus completing the resource recovery of the second-step stope.

[0073] At the boundary of the second-step stope near the peach-shaped pillar 7, an inclined hole 26 for the peach-shaped pillar is constructed at an angle that matches the inclined hole of the first-step stope. Through directional blasting, an inclined surface on the other side of the peach-shaped pillar 7 is formed in the ore body, which together with the inclined surface formed in step S40 constitutes a complete peach-shaped outline.

[0074] Using the intermittent pre-splitting space 8 formed in the previous S30 step, the bottom of the continuous ore body is divided into multiple independent units. Each unit is isolated from the others by the pre-splitting space 8, forming a distributed ore pillar group, that is, forming the bottom structure 22, to avoid the overall destruction caused by excessive force on a single unit.

[0075] In this example, the peach-shaped pillar 7, together with the other infill materials, forms a rigid load-bearing section, bearing the main load and resisting overall structural instability; the pre-splitting space 8 forms a flexible unloading section, absorbing local deformation and blocking stress transmission. Traditional bottom structures are continuous monolithic; once local stress concentration or damage occurs, it will rapidly spread through connected tunnels. The pre-splitting space, by actively creating physical intervals, endows the system with flexible unloading capabilities. When the surrounding rock transmits the maximum principal stress, the pre-splitting space can block the continuous transmission of stress: after the stress reaches the pre-splitting space, it will be significantly attenuated due to the lack of rock mass support in the interval zone, preventing it from being transmitted to the peach-shaped pillar or bottom structure of adjacent units, thus resolving structural damage caused by stress concentration. When the infill material experiences slight settlement due to shrinkage, the voids in the pre-splitting space can provide a certain deformation margin; the settlement deformation is limited to the current unit and will not be transmitted to other units through the continuous structure, avoiding overall instability caused by local deformation.

[0076] The special feature of placing the pre-splitting space 8 inside the peach-shaped pillar 7 is that the peach-shaped pillar is a stress concentration area in the bottom structure. By placing the pre-splitting space specifically inside the peach-shaped pillar, the excessive stress inside the peach-shaped pillar can be relieved, thereby maintaining the integrity of the load-bearing structure of the peach-shaped pillar and avoiding instability of the load-bearing structure caused by stress concentration.

[0077] Two peach-shaped pillars containing pre-fractured spaces are not adjacent, meaning that there must be at least one complete peach-shaped pillar between them. The advantage of a peach-shaped pillar with pre-fractured spaces is its ability to release loads, but its weakness is slightly lower load-bearing stiffness. A complete peach-shaped pillar has the advantage of high load-bearing stiffness, but its weakness is that it will completely absorb stress, leading to cracking. The design, by separating them by at least one complete pillar, allows the advantages of both to complement each other, which is beneficial for the formation of a rigid-flexible coupled bottom structure.

[0078] This application provides a method for constructing a distributed rigid-flexible coupled bottom structure, including:

[0079] S10. Arrange the preparation work in the bottom structure of the ultra-large-scale panel area;

[0080] S20. In the bottom structure of the ultra-large-scale panel, pre-splitting blast holes are arranged at intervals along the strike of the ore body to be mined.

[0081] S30. Perform pre-splitting blasting to create a pre-splitting space;

[0082] S40, the first-stage mining area is mined, and an inclined surface on one side of the peach-shaped pillar is formed in the ore body by means of construction inclined holes and blasting.

[0083] S50. Construct an arched filling retaining wall at the pre-fractured space that has been formed in the peach-shaped pillar ore roadway. At the same time, set up an additional retaining wall at the intersection of the ore roadway of the first and second step mining areas, and then fill the goaf of the first step mining area.

[0084] S60. After the filling body of the first-step stope reaches the design strength and is fully consolidated, the second-step stope mining operation is carried out. Similarly, the inclined surface on the other side of the peach-shaped pillar is formed by constructing inclined holes and blasting, thus forming the peach-shaped pillar.

[0085] By actively cutting off the stress transmission path of the rock mass through pre-splitting space, the continuous bottom structure is divided into independent units, thereby solving the problems of maximum principal stress concentration and cumulative transmission of blasting vibration. On the other hand, the step-by-step mining combined with the formation of peach-shaped pillars, combined with the filling body formed by double retaining walls, forms a rigid-flexible coupling system that combines rigid pillar bearing with flexible interval unloading. This system not only resists structural deformation caused by the settlement of the filling body, but also avoids the chain reaction of local damage, thus specifically solving the core problems of insufficient bottom structure stability and easy production interruption in traditional methods.

[0086] In some implementations, refer to Figure 1 The preparation work includes the construction of the ore receiving roadway, ore exit roadway and ore exit approach roadway in sequence, based on the development works such as the upper plate haulage roadway, lower plate haulage roadway and plate cross-vein roadway, to form a complete bottom structure engineering system of the plate.

[0087] For example, based on the existing development works such as the upper plate haulage roadway 2, the lower plate haulage roadway 16, and the panel cross-vein connecting roadway 17, the receiving roadway 18 of the first-stage stope and the receiving roadway 20 of the second-stage stope are constructed in sequence, followed by the construction of the ore extraction roadway 4. Finally, the construction of the ore extraction access roadway 19 of the first-stage stope and the ore extraction access roadway 21 of the second-stage stope is promoted respectively, so that the receiving roadway, the ore extraction roadway and the ore extraction access roadway are interconnected and together form a complete panel bottom structure engineering system.

[0088] Simultaneously, in accordance with the needs of panel mining, the construction of external connecting tunnel 12, panel chute 1, and return air shaft 6 were carried out.

[0089] In some implementations, refer to Figure 2The cross-sectional dimensions of the receiving tunnel, the exit tunnel, and the exit entrance must meet the requirements for ore extraction and ventilation, and provide operating space for subsequent pre-splitting blasting operations.

[0090] In some implementations, refer to Figure 2 The pre-splitting blast holes are arranged along the extension direction of the ore exit roadway of the bottom structure, and a buffer layer is reserved between the bottom of the pre-splitting blast holes and the boundary of the bottom structure; the buffer layer is used to avoid damage to the main body of the bottom structure caused by the pre-splitting blasting, so as to accurately control the blasting influence range.

[0091] For example, the pre-splitting blast holes 9 are continuously arranged along the extension direction of the ore extraction roadway 4 of the bottom structure, and a certain thickness of rock mass is reserved between the bottom of each pre-splitting blast hole and the boundary of the bottom structure as a buffer layer, such as a 1-meter-thick rock mass. The buffer layer can absorb part of the energy of the pre-splitting blast, prevent the blast shock wave from directly acting on the main body of the bottom structure, prevent the roadway walls of the receiving roadway and the ore extraction roadway from cracking or deforming, protect the integrity of the bottom structure 22, and ensure that the pre-splitting space 8 is formed only inside the peach-shaped pillar 7 and does not affect the surrounding ore extraction roadway.

[0092] In some implementations, refer to Figure 2 The pre-splitting blasting employs a staggered, decoupled charge structure. For example, during pre-splitting blasting, a staggered, decoupled charge is used within the pre-splitting borehole 9, meaning a gap is left between the explosive and the borehole wall, and the charge positions of adjacent boreholes are staggered and not aligned in a straight line. The decoupled charge reduces the impact pressure of the blast on the borehole wall, decreases the degree of fragmentation of the rock pillar, ensures the smooth boundary of the pre-splitting space 8, and avoids the formation of irregular cracks. The staggered arrangement allows for a uniform distribution of blasting energy, ensuring the precise formation of the pre-splitting space 8 along the designed direction, while reducing disturbance to adjacent pillar sub-units.

[0093] In some implementations, refer to Figure 4 In the first-step stope mining, upward-facing fan-shaped medium-deep holes are constructed in the upper section of the drilling roadway and the bottom receiving roadway of the stope. Simultaneously, inclined short blast holes are constructed near the stope boundary in the receiving roadway. These inclined short blast holes are used to form ore drop channels to improve ore flowability and ore extraction efficiency. For example, in the first-step stope mining, blast holes are constructed in two steps: upward-facing fan-shaped medium-deep holes are constructed in the upper section of the drilling roadway, and downward-facing short blast holes are constructed near the stope boundary in the receiving roadway 18 of the first-step stope. The blasting of these inclined short blast holes forms an ore drop channel 27.

[0094] In some implementations, refer to Figure 4In the one-step stope mining, blasting adopts a row-by-row micro-delay initiation method for medium-deep holes. For example, during the medium-deep hole blasting in the one-step stope mining, the blasting is carried out in a row-by-row initiation mode, and a micro-delay is set between each row of blast holes. Row-by-row micro-delay initiation can control the intensity of blasting vibration and avoid damage to the bottom structure or peach-shaped pillars 7 by the strong shock waves generated by the simultaneous blasting of multiple rows of blast holes. The blasting of the subsequent row of blast holes can compress the ore blasted in the previous row, promote ore crushing, and at the same time avoid ore splashing too far, thereby improving blasting safety and ore crushing quality.

[0095] In some implementations, refer to Figure 1 , 2 4. Each time, a preset number of blast holes are detonated. The blast holes within a row are detonated in at least two segments according to a slight delay, and delayed blasting is used between rows. For example, during mining blasting, only a preset number of blast holes are detonated each time; the blast holes within the same row are divided into at least two segments according to a slight delay and detonated sequentially; delay intervals are also set between different rows. By controlling the amount of explosive initiation in a single segment, the peak value of blasting vibration is further reduced, protecting the pre-splitting space 8 and the bottom structure 22 from impact. Segmented detonation within a row can avoid the formation of large blocks caused by mutual compression of ore within the same row. The delay between rows can reserve time for ore to fall, preventing blockage of the ore extraction access 19 in the first-step stope and improving the continuity of ore extraction.

[0096] In some implementations, refer to Figure 3 and Figure 5 While constructing the arched backfill retaining wall, an additional retaining wall is installed at the intersection of the receiving roadways of the primary and secondary mining areas. For example, after the primary mining area is mined, an arched backfill retaining wall 10 is constructed. Simultaneously, an additional retaining wall, namely the secondary mining receiving roadway backfill retaining wall 31, is installed at the intersection of the primary mining receiving roadway 18 and the secondary mining receiving roadway 20. The arched backfill retaining wall bears the main pressure of the backfill material, while the additional retaining wall, as secondary protection, prevents leakage of the backfill material from the gap between the two receiving roadways, avoiding blockage of the receiving roadway or contamination of the secondary mining area. The intersection section is a stress concentration area; the additional retaining wall enhances the structural stability of this area, providing a safety boundary for the mining of the secondary mining area.

[0097] In some implementations, refer to Figure 1 and Figure 4During the second-stage stope mining, the layout logic of the upward-facing fan-shaped deep boreholes and the inclined short blast holes used to form the ore drop trench is consistent with that of the first-stage stope. Furthermore, when the inclined holes form the other side of the peach-shaped pillar, their construction direction matches that of the inclined holes used in the first-stage stope to form one side of the peach-shaped pillar. For example, during the second-stage stope mining, the layout logic of the upward-facing fan-shaped deep boreholes and the inclined short blast holes at the receiving roadway 20 in the second-stage stope is completely consistent with that of the first-stage stope. When the inclined holes form the other side of the peach-shaped pillar 7, their construction direction matches that of the inclined holes used in the first-stage stope to form the other side of the pillar. This consistent hole layout logic reduces construction difficulty, ensures consistent mining efficiency and ore recovery rate between the two stages of the stope, and ensures precise connection between the two sides of the peach-shaped pillar 7, forming a complete peach-shaped load-bearing structure. This avoids stress concentration caused by irregular pillar shapes and improves the pillar's load-bearing stability.

[0098] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

[0099] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for constructing a distributed rigid-flexible coupled bottom structure, characterized in that, include: Preparatory work is carried out in the bottom structure of the ultra-large-scale panel area; In the bottom structure of the ultra-large-scale panel, pre-splitting blast holes are arranged at intervals along the strike of the body to be mined. The pre-splitting blast holes are arranged along the extension direction of the ore outlet roadway of the bottom structure, and a buffer layer is reserved between the bottom of the pre-splitting blast holes and the boundary of the bottom structure. The buffer layer is used to prevent the pre-splitting blast from damaging the main body of the bottom structure, so as to accurately control the blasting impact range; Pre-splitting blasting is carried out to form a pre-splitting space, which is located within a peach-shaped pillar, and the two peach-shaped pillars containing the pre-splitting space are not adjacent. The first-stage mining area is back-mined, and an inclined surface on one side of the peach-shaped pillar is formed in the ore body by means of construction inclined holes and blasting. An arched filling retaining wall is constructed at the pre-fractured space that has been formed in the peach-shaped pillar ore roadway. At the same time, an additional retaining wall is set at the intersection of the ore roadways of the first and second step mining areas, and then the goaf of the first step mining area is filled. After the filling material in the first-stage stope reaches the designed strength and is fully consolidated, the second-stage stope mining operation is carried out. Similarly, the inclined surface on the other side of the peach-shaped pillar is formed by constructing inclined holes and blasting, thus forming the peach-shaped pillar.

2. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 1, characterized in that, The preparation project includes the sequential construction of the receiving roadway, the ore extraction roadway, and the ore extraction access roadway, based on the upper plate haulage roadway, the lower plate haulage roadway, and the plate cross-vein roadway, to form a complete bottom structure engineering system for the plate.

3. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 2, characterized in that, The cross-sectional dimensions of the receiving roadway, the exit roadway, and the exit access road must meet the requirements for ore extraction and ventilation, and provide operating space for subsequent pre-splitting blasting operations.

4. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 1, characterized in that, The pre-splitting blasting employs an interleaved, decoupled charge structure.

5. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 1, characterized in that, During the first-stage mining operation, upward fan-shaped medium-deep holes are constructed in the upper section of the rock drilling roadway and the bottom ore receiving roadway of the mining area. At the same time, inclined short blast holes are constructed near the boundary of the mining area in the ore receiving roadway. The inclined short blast holes are used to form ore drop troughs to improve ore flowability and ore extraction efficiency.

6. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 4, characterized in that, The blasting for the first-stage mining operation adopts a medium-deep hole row-by-row micro-differential blasting method.

7. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 6, characterized in that, Each time, a preset number of blast holes are detonated. The blast holes within a row are detonated in at least two separate sequences with a slight delay, and delayed blasting is used between rows.

8. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 1, characterized in that, While constructing the arched filling retaining wall, an additional retaining wall is set up in the section where the receiving roadway of the first-stage mining area and the second-stage mining area intersects.

9. The method for constructing a distributed rigid-flexible coupled bottom structure according to claim 1, characterized in that, During the two-step mining operation, the layout logic of the upward fan-shaped medium-deep holes and the inclined short blast holes used to form the ore drop trough is consistent with that of the one-step mining operation; and when the inclined holes are used to form the other side of the peach-shaped pillar, the construction direction of the inclined holes is adapted to the inclined holes used to form the other side of the peach-shaped pillar in the one-step mining operation.

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