Construction method of open-pit mine end-slope pre-buried tunnel transportation system

Abstract

The application discloses a construction method of an open-pit mine end-slope pre-buried tunnel transportation system, which comprises the following steps: building a pseudo-inclined path as an end-slope pseudo-inclined base on the end-slope of an open-pit mine; building a pit bottom horizontal base on the pit bottom from the terminal position of the end-slope pseudo-inclined base to the side of a mining field; building a pre-buried tunnel on the surface of a reinforcing layer of the end-slope pseudo-inclined base and the pit bottom horizontal base after the base is built; the pre-buried tunnel is formed by connecting a plurality of precast tunnel pieces; and setting a transportation system in the tunnel. With the mining of the open-pit mine, the mining field is continuously advanced, and the pit bottom horizontal base and the tunnel are continuously extended and built according to the above steps. The tunnel is arranged on the end-slope and the pit bottom, and both are excavated, so that the deformation is small, the tunnel has a certain flexibility, and the horizontal stress caused by the change of the terrain to the tunnel is effectively resisted. The reinforcing layer is cast in the base, so that a solid bottom foundation is further provided for the tunnel, and the vertical deformation of the terrain is avoided.

Description

Technical Field

[0001] This invention relates to a method for constructing a tunnel transportation system, specifically a method for constructing a pre-buried tunnel transportation system at the end of an open-pit mine. Background Technology

[0002] The layout and relocation of continuous transport systems in open-pit mines can significantly disrupt all major aspects of mining operations, including production, transportation, and spoil disposal. Some scholars have proposed pre-burying tunnels in spoil heaps to provide space for the continuous transport system, which could mitigate these adverse effects. However, since spoil heaps are artificially constructed earth and rock masses with limited density and bearing capacity, uneven settlement can exert lateral and longitudinal stresses on the pre-buried tunnels, posing a major technical bottleneck for the large-scale application of tunnel transport solutions. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a construction method for a pre-buried tunnel transportation system at the end of an open-pit mine. The pre-buried tunnel can resist the stress in the lateral and longitudinal directions caused by uneven settlement of the spoil heap, thereby improving the stability and safety of the pre-buried tunnel.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for constructing a pre-buried tunnel transportation system at the end of an open-pit mine, comprising the following steps: Foundation Construction: Starting from the surface, a pseudo-sloping passage is constructed along the direction from the spoil heap to the mining area on the end face of the open-pit mine. The passage extends all the way to the bottom of the pit, serving as the pseudo-sloping foundation of the end face. The starting point of the pseudo-sloping foundation is located 30-50m from the top of the uppermost spoil heap slope, and the ending point is located 20-30m from the bottom of the lowermost mining bench slope. Starting from the ending point of the pseudo-sloping foundation, a horizontal foundation is constructed at the bottom of the pit towards the mining area. Both the pseudo-sloping foundation and the horizontal foundation at the bottom are reinforced with reinforced concrete to form a reinforcement layer. During the pouring process, multiple steel bars are inserted at intervals into the rock mass at the bottom and sides of the foundation. Tunnel layout and surrounding rock reconstruction: After the foundation is completed, pre-embedded tunnels are constructed on the surface of the reinforcement layer on the pseudo-inclined foundation at the end and the horizontal foundation at the bottom of the pit. The pre-embedded tunnels are formed by connecting multiple precast tunnel components end to end. As the spoil heap is continuously advanced, the precast tunnel components are gradually buried. When the precast tunnel components are about to be buried, fine sand is laid within a range of 2-3m around the precast tunnel components, and then crushed stone is laid within a range of 3-5m around the precast tunnel components. After the tunnel layout and surrounding rock reconstruction are completed, a transportation system is set up in the tunnel. As the open-pit mine is mined, the mining area continues to advance, and the horizontal foundation and tunnel at the bottom of the pit are continuously extended and constructed in accordance with the above steps.

[0005] Furthermore, the pseudo-inclined base at the end of the end slope is offset away from the bottom of the pit at the starting end on the ground surface.

[0006] Furthermore, the width of the reinforcement layer is 3-5m wider than that of the precast tunnel component.

[0007] Furthermore, the horizontal foundation of the end side is constructed on the end side bench in accordance with the method of constructing the horizontal foundation of the pit bottom. One end of the horizontal foundation of the end side is connected to the pseudo-inclined foundation of the end side, and the other end extends towards the mining area. A pre-embedded tunnel is constructed on the horizontal foundation of the end side.

[0008] Furthermore, the precast tunnel component is a concrete square tube structure. The front and rear ends of the left and right sides of the square tube are straight, while the front and rear ends of the top and bottom sides of the square tube are outwardly protruding arcs, and a connecting hole is provided at the top of the arc.

[0009] Furthermore, after the prefabricated tunnel components are connected end to end, a rubber wrapping layer is provided around the connection point.

[0010] Furthermore, the angle between the pseudo-oblique base of the end side and the horizontal plane does not exceed 14°.

[0011] Compared to existing technologies, this invention deploys tunnels at the end walls and bottom of the pit, both of which are excavations. Compared to deployments at spoil heaps, the foundation and surrounding rock at the end walls and bottom of the pit are more stable, with less deformation and less damage to the system. The precast tunnel components feature an arc-shaped interface design, enabling rotational deformation and giving the tunnel a certain degree of flexibility, effectively resisting horizontal stress caused by terrain changes. A reinforcing layer is poured into the foundation, further providing a solid bottom foundation for the tunnel and preventing vertical deformation due to terrain. The reconstruction of the surrounding rock provides damping space for tunnel deformation, ensuring that even if deformation occurs, the tunnel will not be easily damaged. The reinforcing layer consists of extra-wide precast tunnel components (3-5m), ensuring that even small displacements of the components will not affect their vertical support. Subsequent extensions only require horizontal tunnel sections, simplifying the operation and minimizing impact on mining production. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the tunnel component structure of the present invention; Figure 3 This is a partial schematic diagram of the reinforcement layer of the present invention; In the diagram: 1-Precast tunnel component; 2-Left and right sides of square tube; 3-Upper and lower sides of square tube; 4-Connecting hole; 5-Pseudo-inclined foundation of end side; 6-Horizontal foundation of pit bottom; 7-End side of open-pit mine; 8-Surface; 9-Rollover dump; 10-Mining area; 11-Pit bottom; 12-Lowest coal mining bench; 13-Reinforcing bar; 14-Horizontal foundation of end side; 15-Reinforcement layer. Detailed Implementation

[0013] The invention will now be further described with reference to the accompanying drawings.

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] This invention provides a technical solution, such as Figure 1 As shown, it includes the following steps.

[0016] Foundation Construction: Starting from the surface 8, a pseudo-sloping passage is constructed along the direction from the spoil heap 9 to the mining area 10 on the open-pit end face 7, extending all the way to the pit bottom 11. This passage serves as the pseudo-sloping foundation 5 of the end face, with the angle between the pseudo-sloping foundation 5 and the horizontal plane not exceeding 14°. The starting point of the pseudo-sloping foundation 5 is located 30-50m from the top of the uppermost open-pit spoil heap slope, and the ending point is located 20-30m from the bottom line of the lowermost mining bench 12 slope. To ensure that the pseudo-sloping foundation 5 is entirely excavated during construction and avoids backfilling, the starting point of the pseudo-sloping foundation 5 at the surface 8 can be offset away from the pit bottom 11 during construction. Figure 1 The center should be shifted to the right, and the shift distance should be determined according to the actual site conditions, generally 30-50m is sufficient.

[0017] After the end-side pseudo-inclined base 5 is constructed, starting from the end position of the end-side pseudo-inclined base 5, the pit bottom horizontal base 6 is constructed on the pit bottom 11 towards the mining area 10. The pit bottom horizontal base 6 is arranged against the bottom of the slope of the lowest mining bench 12, which can avoid lateral unbalanced forces to a certain extent.

[0018] Both the pseudo-sloping end base 5 and the horizontal base 6 at the bottom of the pit were excavated, and the bases were in the shape of a groove. After the bases were constructed, reinforced concrete was poured into both the pseudo-sloping end base 5 and the horizontal base 6 to form a reinforcement layer 15 for reinforcement. During the pouring of the reinforcement layer 15, if... Figure 3 As shown, multiple steel bars 13 are inserted at intervals into the rock mass at the bottom and sides of the base; this ensures that the reinforcement layer 15 is fully connected to the surrounding rock mass, thereby improving the integrity and strength of the reinforcement layer 15.

[0019] When encountering a very thick coal seam, multiple horizontal bases 14 can be laid out on the end bench according to the layout and construction method of the pit bottom horizontal base 6. One end of the horizontal base 14 is connected to the end pseudo-inclined base 5, and the other end extends towards the mining area 10. Setting up multiple horizontal bases 14 can solve the problem of lifting coal at different horizontal heights.

[0020] Tunnel Layout and Surrounding Rock Reconstruction: After the foundation is constructed, pre-embedded tunnels are constructed on the surface of the reinforcement layer 15 on the pseudo-inclined foundation 5 at the end side and the horizontal foundation 6 at the bottom of the pit, respectively. If there is a horizontal foundation 14 at the end side, then a pre-embedded tunnel is also constructed on the surface of the reinforcement layer 15 on the horizontal foundation 14 at the end side. The pre-embedded tunnel is formed by connecting multiple prefabricated tunnel components 1 end to end in sequence. The width of the reinforcement layer 15 is 3-5m wider than the prefabricated tunnel component 1. Figure 2 As shown, the precast tunnel component 1 is a concrete square tube structure. The front and rear ends of the left and right sides 2 of the square tube are straight, while the front and rear ends of the top and bottom sides 3 are outwardly convex arcs, with connecting holes 4 at the top and bottom arcs. When connecting, the connecting holes 4 of the two precast tunnel components 1 overlap, and the two precast tunnel components 1 are connected together by bolts. A single precast tunnel component 1 is rigid, but it can rotate within a certain range with the connecting hole 4 as a hinge point, realizing the lateral displacement of the position of each precast tunnel component 1. Ultimately, this results in the tunnel as a whole having a certain degree of flexibility, thereby offsetting lateral stress. To ensure that no foreign objects enter the precast tunnel component 1, after the precast tunnel components 1 are connected end to end, a rubber wrapping layer is set around the connection point. This does not affect the connection of the precast tunnel components 1, but also achieves a seal at the interface of the two precast tunnel components 1.

[0021] As the spoil heap 9 continues to advance, the precast tunnel component 1 is gradually buried. When the precast tunnel component 1 is about to be buried, fine sand with a diameter of 0.5-5cm is laid within a range of 2-3m around the precast tunnel component 1. Then, crushed stone with a particle size of 5-20cm is laid within a range of 3-5m around the precast tunnel component 1. When the tunnel shifts, the small particles of fine sand and the large particles of crushed stone squeeze each other, which can produce a certain deformation and provide damping space for tunnel deformation. At the same time, the small particles of fine sand close to the outside of the precast tunnel component 1 cause less damage to the outer surface of the precast tunnel component 1.

[0022] After the tunnel layout and surrounding rock reconstruction are completed, a transportation system is set up in the tunnel. As the open-pit mine is mined, the mining area 10 continues to advance. Following the above steps, the horizontal foundation 6 at the bottom of the pit and the tunnel are continuously extended and constructed, avoiding continuous interference with other systems in the open-pit mine.

[0023] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0024] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a transportation system for a pre-buried tunnel at the end of an open-pit mine, characterized in that, Includes the following steps: Foundation construction: Starting from the surface (8), along the direction from the spoil heap (9) to the mining area (10), a pseudo-sloping passage is constructed on the end wall (7) of the open-pit mine. The passage extends all the way to the bottom of the pit (11). The passage serves as the pseudo-sloping foundation (5) of the end wall. The starting point of the pseudo-sloping foundation (5) is located 30-50m away from the top of the uppermost spoil heap slope, and the ending point of the pseudo-sloping foundation (5) is located 20-30m away from the bottom of the lowermost mining bench (12). Starting from the end position of the pseudo-sloping base (5), construct the pit bottom horizontal base (6) in the direction of the mining area (10) at the pit bottom (11). In both the pseudo-sloping base (5) at the end and the horizontal base (6) at the bottom of the pit, reinforced concrete was poured to form a reinforcement layer (15) for reinforcement. During the pouring process, multiple steel bars (13) were inserted at intervals into the rock mass at the bottom and sides of the base. Tunnel layout and surrounding rock reconstruction: After the foundation is completed, pre-embedded tunnels are constructed on the surface of the reinforcement layer (15) on the end pseudo-sloping foundation (5) and the horizontal foundation (6) at the bottom of the pit. The pre-embedded tunnels are formed by connecting multiple precast tunnel components (1) end to end in sequence. As the spoil heap (9) continues to advance, the precast tunnel components (1) are gradually buried. When the precast tunnel components (1) are about to be buried, fine sand is laid within a range of 2-3m around the precast tunnel components (1), and then crushed stone is laid within a range of 3-5m around the precast tunnel components (1). After the tunnel layout and surrounding rock reconstruction are completed, a transportation system is set up in the tunnel. As the open-pit mine is mined, the mining area (10) continues to advance. The pit bottom horizontal base (6) and tunnel are continuously extended and constructed in accordance with the above steps.

2. The construction method of a pre-buried tunnel transportation system for open-pit mine end face as described in claim 1, characterized in that: The pseudo-inclined base (5) at the starting end of the surface (8) is offset to the side away from the bottom of the pit (11).

3. The construction method of a pre-buried tunnel transportation system for an open-pit mine end face as described in claim 1, characterized in that: The width of the reinforcing layer (15) is 3-5m wider than that of the precast tunnel component (1).

4. The construction method of a pre-buried tunnel transportation system for open-pit mine end face as described in claim 1, characterized in that: On the end side step, the end side horizontal base (14) is constructed in accordance with the method of constructing the pit bottom horizontal base (6). One end of the end side horizontal base (14) is connected to the end side pseudo-inclined base (5), and the other end extends towards the mining area (10). A pre-embedded tunnel is constructed on the end side horizontal base (14).

5. The construction method of a pre-buried tunnel transportation system for an open-pit mine end face as described in claim 1, characterized in that: The precast tunnel component (1) is a concrete square tube structure. The front and rear ends of the left and right sides (2) of the square tube are straight, and the front and rear ends of the upper and lower sides (3) of the square tube are outwardly protruding arcs, and a connecting hole (4) is provided at the top of the arc.

6. The construction method of a pre-buried tunnel transportation system for an open-pit mine end face as described in claim 5, characterized in that: After the prefabricated tunnel components (1) are connected end to end, a rubber wrapping layer is set around the connection.

7. The construction method of a pre-buried tunnel transportation system for an open-pit mine end face as described in claim 1, characterized in that: The angle between the pseudo-oblique base (5) at the end and the horizontal plane does not exceed 14°.

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