Method and device for reinforcing well mouth earth surface strongly-weathered rock stratum of deep shaft

Abstract

The invention relates to a method and device for reinforcing a well mouth earth surface strongly-weathered rock stratum of a deep shaft. In the method for reinforcing the well mouth earth surface strongly-weathered rock stratum of the deep shaft, the ground is cleaned and leveled. A plurality of foundation piles are arranged in the circumferential direction of a wellhead of the deep vertical shaft, extend along the axis of the deep vertical shaft and partially extend into the strongly weathered rock stratum. The sides, close to the axis of the deep shaft, of the foundation piles form an inner contour line, circles of the foundation piles form a center loop line, and the inner side face contour line of the deep shaft is located between the inner contour line and the center loop line so as to determine the inner side face contour line of the deep shaft. And counter-pulling from the bottom of the deep shaft to the wellhead along the inner side profile of the deep shaft. According to the method, after the stable foundation piles are formed, the outline of the deep shaft is defined, then counter-pulling is conducted in the outline, the structural stability is guaranteed, the counter-pulling cutting part is mainly the structure of the foundation piles, therefore, the situation that loose blocks fall off is prevented, and the construction efficiency, safety and stability of the deep shaft are improved.

Description

Technical Field

[0001] This application relates to the field of water conservancy and hydropower construction technology, and in particular to a method and device for reinforcing strongly weathered rock strata at the wellhead of deep vertical shafts. Background Technology

[0002] To achieve the goals of "carbon peaking and carbon neutrality," the National Energy Administration has proposed that my country's overall energy development strategy is to continuously promote the green and low-carbon transformation of energy while ensuring energy security. Currently, my country's total fossil fuel consumption is gradually decreasing, while renewable energy sources such as wind power and solar power are growing rapidly. However, wind and solar power suffer from high volatility and cannot provide continuous and stable output, necessitating increased investment in peak-shaving and frequency-regulating power sources to ensure the safety and stability of the power grid. Pumped storage hydroelectric power stations, due to their functions of peak shaving and valley filling, frequency and phase regulation, stabilizing power system cycles and voltage, and systemic energy conservation, are poised for rapid development in the coming years to achieve the "dual carbon" goals.

[0003] To achieve the goal of "replacing manpower with mechanization, reducing manpower with automation, and unmanned operation with intelligent systems," traditional drilling and blasting methods and related machinery and equipment will inevitably be phased out. For deep vertical shaft construction, the one-time forming technology for large-diameter reverse shafts has gradually matured. However, most deep vertical shafts have wellheads covered by 10-20m of strongly weathered rock or even soil layers. After reverse pulling, the fractured rock layer at the wellhead has low self-stability, frequent rockfalls, and forms cavities. Conventional methods include surface cement grouting for consolidation before reverse pulling, but this often results in inadequate consolidation or the presence of loose blocks. Arranging a hoisting system and using mechanical breaking and drilling methods for forward excavation and lining poses significant safety hazards and high construction costs. Summary of the Invention

[0004] Therefore, it is necessary to address the problems of conventional deep vertical shaft surface wellhead reinforcement methods, such as pre-pull-back surface cement grouting consolidation, which often suffers from inadequate consolidation or the presence of loose blocks. These methods involve arranging a hoisting system, using mechanical crushing and drilling methods for forward excavation and lining, which pose significant construction safety hazards and high construction costs. To provide a method and device for reinforcing the surface of strongly weathered rock strata at the wellhead of deep vertical shafts, it is necessary to address these issues.

[0005] A method for reinforcing the strongly weathered rock strata at the wellhead of a deep vertical shaft includes the following steps:

[0006] Clean and level the ground;

[0007] Multiple foundation piles are installed around the circumference of the wellhead of the deep vertical shaft, and the foundation piles extend along the axis of the deep vertical shaft and partially extend into the strongly weathered rock layer.

[0008] The inner contour line is formed by the side of the foundation piles near the axis of the deep shaft, and the circles of the foundation piles form a central ring. The inner side contour line of the deep shaft is located between the inner contour line and the central ring to determine the inner side contour line of the deep shaft.

[0009] The cutting tool is used to pull the deep shaft from the bottom to the opening along the inner contour of the shaft.

[0010] When constructing a deep shaft using the aforementioned method of reinforcing the surface of strongly weathered rock at the shaft opening, multiple foundation piles are installed around the circumference of the shaft opening to form the circumferential outline of the deep shaft. These foundation piles extend along the shaft's axis and partially penetrate the strongly weathered rock layer. This arrangement of foundation piles around the shaft connects and fixes the geological rock layers on both sides of the boundary line of the strongly weathered rock layer, ensuring the deep shaft is relatively stable. Then, the inner contour line formed by the multiple foundation piles and the central ring line determine the inner side contour line of the deep shaft located between these two lines. Thus, the outer wall of the deep shaft at the point where the inner side contour line is pulled back is mostly composed of foundation piles rather than rock layers. The pull-back process cuts part of the foundation pile structure, thus minimizing the use of foundation piles to enclose the deep shaft rather than the rock layers. The above method ensures structural stability by forming a deep shaft outline after the foundation piles are formed, and then applying reverse tension within the outline. The reverse tension cuts mainly on the foundation pile structure, thereby preventing loose blocks from falling and improving the construction efficiency and safety stability of the deep shaft.

[0011] In one embodiment, the foundation piles include a first foundation pile and a second foundation pile, and the step of setting a plurality of the foundation piles circumferentially around the opening of the deep vertical shaft includes:

[0012] Multiple first foundation piles are arranged around the circumference of the wellhead of the deep vertical shaft, and the multiple first foundation piles are arranged at intervals along the circumference of the deep vertical shaft;

[0013] Multiple second foundation piles are installed around the circumference of the opening of the deep vertical shaft, and the first foundation piles and the second foundation piles are arranged alternately around the circumference of the deep vertical shaft.

[0014] In one embodiment, the cross-section of the second foundation pile partially overlaps with that of the adjacent first foundation pile.

[0015] In one embodiment, the second foundation pile is installed after the first foundation pile has reached 70% solidification.

[0016] In one embodiment, the arrangement of a plurality of the first foundation piles circumferentially around the opening of the deep shaft includes:

[0017] Multiple first holes are opened around the circumference of the wellhead of the deep vertical shaft;

[0018] A first reinforcing cage coaxial with the first hole is placed into each first hole;

[0019] Concrete is injected into the first hole.

[0020] In one embodiment, the arrangement of a plurality of second foundation piles circumferentially around the opening of the deep shaft includes:

[0021] Multiple second holes are opened around the circumference of the wellhead of the deep vertical shaft;

[0022] A second reinforcing cage coaxial with the second hole is placed in each second hole, and the outer periphery of the second reinforcing cage is tangent to the outer periphery of the adjacent first hole, so that the two sides of the second hole coincide with the cross-sectional portion of the adjacent first hole respectively.

[0023] Concrete is injected into the second hole.

[0024] In one embodiment, the step of placing a reinforcing cage coaxial with the first hole into each of the first holes further includes:

[0025] A first positioning element is installed at the opening of the first hole;

[0026] One end of the first reinforcing cage and the first positioning member can move radially along the first hole, while the other end abuts against the bottom wall of the first hole;

[0027] The first reinforcing cage is moved radially along the first hole so that the first reinforcing cage is coaxially arranged with the first hole.

[0028] In one embodiment, the step of pulling the deep shaft back from the bottom to the opening along the inner side profile of the deep shaft using a cutter further includes:

[0029] Multiple anchor bolt assemblies are arranged circumferentially around the deep shaft, such that one end of each anchor bolt assembly is connected to the foundation pile and the other end is fixed to the ground.

[0030] In one embodiment, the angle between the anchor bolt assembly and the axis of the deep shaft is set to 15°-25°.

[0031] One embodiment of this application also provides a device for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft, formed by the aforementioned method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft. The device for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft includes:

[0032] Multiple foundation piles are arranged around the circumference of the wellhead of the deep vertical shaft, and the cross sections of two adjacent foundation piles have overlapping areas.

[0033] When constructing a deep shaft using the aforementioned method of reinforcing the surface of strongly weathered rock at the shaft opening, multiple foundation piles are installed around the circumference of the shaft opening to form the circumferential outline of the deep shaft. These foundation piles extend along the shaft's axis and partially penetrate the strongly weathered rock layer. This arrangement of foundation piles around the shaft connects and fixes the geological rock layers on both sides of the boundary line of the strongly weathered rock layer, ensuring the deep shaft is relatively stable. Then, the inner contour line formed by the multiple foundation piles and the central ring line determine the inner side contour line of the deep shaft located between these two lines. Thus, the outer wall of the deep shaft at the point where the inner side contour line is pulled back is mostly composed of foundation piles rather than rock layers. The pull-back process cuts part of the foundation pile structure, thus minimizing the use of foundation piles to enclose the deep shaft rather than the rock layers. The above method ensures structural stability by forming a deep shaft outline after the foundation piles are formed, and then applying reverse tension within the outline. The reverse tension cuts mainly on the foundation pile structure, thereby preventing loose blocks from falling and improving the construction efficiency and safety stability of the deep shaft. Attached Figure Description

[0034] Figure 1 This is a radial cross-sectional view of a device for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft, according to one embodiment.

[0035] Figure 2 This is an axial cross-sectional view of a device for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft, according to one embodiment.

[0036] Figure 3 This is a schematic diagram of a method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft, according to one embodiment.

[0037] Explanation of icon numbers:

[0038] 10-Reinforcement device for strongly weathered rock strata at the wellhead of deep vertical shaft; 11-Inner contour line; 12-Central ring line; 13-Inner side contour line of deep vertical shaft;

[0039] 100 - First foundation pile; 110 - First borehole; 120 - First reinforcing cage;

[0040] 200 - Second foundation pile; 210 - Second borehole; 220 - Second reinforcing cage;

[0041] 300-Anchor Bolt Assembly;

[0042] 21 - Strongly weathered rock strata. Detailed Implementation

[0043] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0044] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0046] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0048] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0049] See Figure 1 and Figure 2 , Figure 1 This illustration shows a schematic diagram of the structure after the surface strongly weathered rock layer at the wellhead of a deep vertical shaft has been fixed, according to an embodiment of this application. The method for reinforcing the surface strongly weathered rock layer 21 at the wellhead of a deep vertical shaft, as provided in this embodiment, reinforces the layer. (See reference...) Figure 3 The method for reinforcing the strongly weathered rock layer at the wellhead of a deep vertical shaft includes the following steps: First, the ground is cleaned and leveled. Then, multiple foundation piles are installed around the circumference of the wellhead, extending along the axis of the deep vertical shaft and partially penetrating the strongly weathered rock layer 21. Next, the foundation piles near the axis of the deep vertical shaft form an inner contour line 11, and the circular shape of the foundation piles forms a central ring line 12. The inner contour line 13 of the deep vertical shaft is located between the inner contour line 11 and the central ring line 12 to define the inner contour line 13 of the deep vertical shaft. Finally, a cutter is used to cut along the inner contour line of the deep vertical shaft from the bottom towards the wellhead, thereby forming the deep vertical shaft.

[0050] When constructing a deep shaft using the above-mentioned method of reinforcing the surface of strongly weathered rock strata at the shaft opening, multiple foundation piles are installed around the circumference of the shaft opening to form the circumferential outline of the deep shaft. The foundation piles extend along the axis of the deep shaft and partially penetrate into the strongly weathered rock strata 21. The geological rock strata on both sides above and below the boundary line of the strongly weathered rock strata 21 are connected and fixed by the multiple foundation piles arranged around the circumference of the deep shaft, ensuring that the enclosed deep shaft is relatively stable. Then, the inner contour line 11 formed by the multiple foundation piles and the central ring line 12 are used to determine the inner side contour line 13 of the deep shaft located between the inner contour line 11 and the central ring line 12. In this way, the outer wall of the deep shaft at the reverse pull cutting point along the inner side contour line 13 of the deep shaft is mostly the structure of the foundation piles rather than the rock strata structure. That is, the reverse pull process will cut part of the structure of the foundation piles, so as to make the foundation piles enclose the deep shaft as much as possible, rather than the rock strata enclose the deep shaft. The above method ensures structural stability by forming a deep shaft outline after the foundation piles are formed, and then applying reverse tension within the outline. The reverse tension cuts mainly on the foundation pile structure, thereby preventing loose blocks from falling and improving the construction efficiency and safety stability of the deep shaft.

[0051] Specifically, the foundation piles should extend at least 1m into the strongly weathered rock layer 21.

[0052] See Figure 1 and Figure 2 In one embodiment, the foundation piles include first foundation piles 100 and second foundation piles 200. The step of circumferentially arranging multiple foundation piles around the opening of the deep shaft includes: arranging multiple first foundation piles 100 around the opening of the deep shaft, with the multiple first foundation piles 100 arranged at intervals along the circumference of the deep shaft; and arranging multiple second foundation piles 200 around the opening of the deep shaft, with the first foundation piles 100 and second foundation piles 200 arranged alternately around the circumference of the deep shaft.

[0053] In this application, multiple first foundation piles 100 are first set at intervals to outline the deep shaft. Then, a second foundation pile 200 is set between two adjacent first foundation piles 100. The multiple first foundation piles 100 and the second foundation pile 200 completely enclose the circumference of the deep shaft. Compared with setting multiple foundation piles sequentially, setting them in batches ensures that the multiple first foundation piles 100 are set on the dense bottom edge, rather than close to the previously set foundation piles. This prevents collapse or fragmentation during the subsequent foundation pile setting, which would affect the setting of subsequent foundation piles and ensure the stability of the deep shaft structure.

[0054] See Figure 1 and Figure 2In one embodiment, the cross-section of the second foundation pile 200 partially overlaps with that of the adjacent first foundation pile 100. In this embodiment, the overlap of the cross-section between the second foundation pile 200 and the adjacent first foundation pile 100 allows for the cutting of portions of the first and second foundation piles 100 during the pull-back process. This ensures that at least a portion of the outer perimeter of the deep shaft is formed by the cutting sections of the first and second foundation piles 100, preventing the detachment of loose blocks such as soil and rock, and guaranteeing the safety and stability of the construction.

[0055] Preferably, the area of ​​the cross-section of the second foundation pile 200 and the adjacent first foundation pile 100 overlaps by 20% of the cross-sectional area of ​​the first foundation pile 100.

[0056] See Figure 1 Preferably, the inner contour line 13 of the deep shaft passes through the intersection of the cross sections of two adjacent foundation piles, thereby ensuring that when the outer contour of the deep shaft is cut, the cut is always the structure of the foundation pile, preventing loose blocks such as soil and rock from falling off, and ensuring the safety and stability of construction.

[0057] See Figure 1 and Figure 2 In one embodiment, the circumferential arrangement of a plurality of first foundation piles 100 around the wellhead of the deep shaft includes:

[0058] Multiple first holes 110 are opened around the circumference of the wellhead of the deep vertical shaft.

[0059] A first steel cage 120, coaxial with the first hole 110, is placed into each first hole 110.

[0060] Concrete was injected into the first hole 110.

[0061] In one embodiment, the circumferential arrangement of a plurality of second foundation piles 200 around the wellhead of the deep shaft includes:

[0062] Multiple second holes 210 are opened around the circumference of the wellhead of the deep vertical shaft.

[0063] A second reinforcing cage 220, coaxial with the second hole 210, is placed into each second hole 210. The outer periphery of the second reinforcing cage 220 is tangent to the outer periphery of the adjacent first hole 110, so that the two sides of the second hole 210 coincide with the cross-sectional portion of the adjacent first hole 110 respectively.

[0064] Concrete was injected into the second hole 210.

[0065] In the above steps, by drilling holes, placing steel cages, and injecting concrete, the first foundation pile 100 and the second foundation pile 200 are formed below the ground to connect and fix the geological structures on both sides of the boundary of the strongly weathered rock layer 21.

[0066] In one embodiment, the first foundation pile 100 reaches 70% solidification before the second foundation pile 200 is installed. In this embodiment, the concrete of the first foundation pile 100 reaches 70% solidification, thus enabling the first foundation pile 100, composed of the first reinforcing cage 120 and solidified concrete, to enclose the outline of the deep shaft. Subsequently, a second hole 210 is opened, wherein the two sides of the second hole 210 coincide with the concrete cross-sections in the first holes 110 on both sides. That is, the second hole 210 will cut off part of the concrete in the first holes 110, but will not cut the first reinforcing cage 120. Then, the second reinforcing cage 220 is placed in sequence and concrete is injected. The first foundation pile 100 and the second foundation pile 200 are arranged alternately to achieve interlocking, which increases the structural stability of the structure enclosed by the first foundation pile 100 and the second foundation pile 200 and improves the stability of the deep shaft after back tension.

[0067] Preferably, the concrete poured into the foundation pile is C30 self-compacting concrete.

[0068] Preferably, the first reinforcing cage 120 and the second reinforcing cage 220 have the same structure, both consisting of multiple vertical distribution bars arranged around the circumference of the corresponding foundation pile. The vertical distribution bars extend along the axis of the foundation pile, and are then secured with multiple circumferential main bars using double-layer binding wire. The multiple circumferential main bars are evenly spaced along the axis of the foundation pile. The circumferential main bars are φ20 (Grade III threaded steel, 200mm spacing), and the vertical distribution bars are φ16 (Grade III threaded steel, 200mm spacing).

[0069] See Figure 1 and Figure 2 In one embodiment, the method further includes, prior to the step of placing a reinforcing cage coaxial with the first hole 110 into each first hole 110:

[0070] A first positioning element is installed at the opening of the first hole 110.

[0071] One end of the first steel cage 120 and the first positioning member can move radially along the first hole 110, while the other end abuts against the bottom wall of the first hole 110.

[0072] The first reinforcing cage 120 is moved radially along the first hole 110 so that the first reinforcing cage 120 is coaxially arranged with the first hole 110.

[0073] Similarly, a second positioning element is provided at the opening of the second hole 210.

[0074] One end of the second steel cage 220 and the first positioning member can move radially along the second hole 210, while the other end abuts against the bottom wall of the second hole 210.

[0075] The second reinforcing cage 220 is moved radially along the second hole 210 so that the second reinforcing cage 220 is coaxially arranged with the second hole 210.

[0076] In this embodiment, by setting a first positioning member at the opening of the first hole 110 and a second positioning member at the opening of the second hole 210, the first reinforcing cage 120 can slide and engage with the first positioning member, and the second reinforcing cage 220 can slide and engage with the second positioning member. This ensures that the first reinforcing cage 120 can be coaxially set with the first hole 110 when pouring concrete, and the second reinforcing cage 220 can be coaxially set with the second hole 210 when pouring concrete. This prevents the first reinforcing cage 120 and the second reinforcing cage 220 from tilting relative to the axis of the deep shaft, ensuring that the overall structure of the first foundation pile 100 and the second foundation pile 200 extends along the axis of the deep shaft, thus ensuring the structural stability of the deep shaft.

[0077] Preferably, a support structure, such as steel bars, is provided on the side of the first foundation pile 100 away from the axis of the deep shaft and on the side of the second foundation pile 200 away from the axis of the deep shaft to support the first foundation pile 100 and the second foundation pile 200 during the reverse tension process.

[0078] See Figure 1 and Figure 2 In one embodiment, the step of pulling the shaft back from the bottom to the opening along the inner profile of the deep shaft using a cutter further includes:

[0079] Multiple anchor bolt assemblies 300 arranged circumferentially around the deep vertical shaft are installed, with one end of each anchor bolt assembly 300 connected to the foundation pile and the other end fixed to the ground. In this embodiment, prestressed anchor plates and anchor blocks are constructed for the prestressed anchor bolt heads. Load transfer is achieved through the combination of prestressed threaded steel bars and anchor plates. In the anti-slip retaining structure, impact force can be converted into tensile force, and energy absorption function is also provided.

[0080] In one embodiment, the angle between the anchor assembly 300 and the axis of the deep shaft is set to 15°-25°. Specifically, the angle between the prestressed threaded steel bar and the axis of the deep shaft is 15°-25°.

[0081] Specifically, after the foundation piles are completed and have undergone 28 days of strength reinforcement, the anchor bolt assembly 300 will be constructed. The anchor bolt body is made of φ28 threaded steel, with a self-drilling drill bit at the front end and a 25×25×2cm (length×width×thickness) anchor plate and a pressure relief ring at the rear end.

[0082] After the anchor bolt assembly 300 is completed, pure cement grout is used for injection with a water-cement ratio of 0.7:1 and an injection pressure of 0.5-0.8MPa. After the tail anchor plate and pressure ring are installed, the site concrete is poured to seal the entire structure.

[0083] Specifically, the anchor bolt assembly 300 comprises two sets. One set of anchor bolt assemblies 300 are arranged sequentially at intervals around the circumference of the deep shaft, while the other set of anchor bolt assemblies 300 are arranged sequentially at intervals around the circumference of the deep shaft on the outer periphery. The distances between the locations of the two sets of anchor bolt assemblies 300 at the ground surface and the axis of the deep shaft are 3m and 4m, respectively. Two anchor bolt assemblies 300 arranged radially along the deep shaft are parallel and spaced 1m apart. The spacing between two adjacent anchor bolt assemblies 300 arranged circumferentially around the deep shaft is 2m.

[0084] Preferably, the angle between the anchor bolt assembly 300 and the axis of the deep shaft is set to 20°.

[0085] An embodiment of this application also provides a device 10 for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft, formed by a method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft. The device 10 includes:

[0086] Multiple foundation piles are installed around the circumference of the wellhead of the deep vertical shaft, and the cross sections of adjacent foundation piles have overlapping areas.

[0087] When constructing a deep shaft using the above-mentioned method of reinforcing the surface of strongly weathered rock strata at the shaft opening, multiple foundation piles are installed around the circumference of the shaft opening to form the circumferential outline of the deep shaft. The foundation piles extend along the axis of the deep shaft and partially penetrate into the strongly weathered rock strata 21. The geological rock strata on both sides above and below the boundary line of the strongly weathered rock strata 21 are connected and fixed by the multiple foundation piles arranged around the circumference of the deep shaft, ensuring that the enclosed deep shaft is relatively stable. Then, the inner contour line 11 formed by the multiple foundation piles and the central ring line 12 are used to determine the inner side contour line 13 of the deep shaft located between the inner contour line 11 and the central ring line 12. In this way, the outer wall of the deep shaft at the reverse pull cutting point along the inner side contour line 13 of the deep shaft is mostly the structure of the foundation piles rather than the rock strata structure. That is, the reverse pull process will cut part of the structure of the foundation piles, so as to make the foundation piles enclose the deep shaft as much as possible, rather than the rock strata enclose the deep shaft. The above method ensures structural stability by forming a deep shaft outline after the foundation piles are formed, and then applying reverse tension within the outline. The reverse tension cuts mainly on the foundation pile structure, thereby preventing loose blocks from falling and improving the construction efficiency and safety stability of the deep shaft.

[0088] The parameters and data of the above schemes are designed based on a diameter of 4m for the deep vertical shaft. When facing the actual site conditions, the specific design can be carried out according to the specific parameters of the deep vertical shaft. There are no restrictions on the parameters of the schemes here.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for reinforcing the strongly weathered rock strata at the wellhead of a deep vertical shaft, characterized in that: The method for reinforcing the strongly weathered rock strata at the wellhead of the deep vertical shaft includes the following steps: Clean and level the ground; Multiple foundation piles are installed around the circumference of the wellhead of the deep vertical shaft, and the foundation piles extend along the axis of the deep vertical shaft and partially extend into the strongly weathered rock layer. The inner contour line is formed by the side of the foundation piles near the axis of the deep shaft, and the circles of the foundation piles form a central ring. The inner side contour line of the deep shaft is located between the inner contour line and the central ring to determine the inner side contour line of the deep shaft. The cutting tool is used to pull the deep shaft from the bottom to the opening along the inner contour of the shaft.

2. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 1, characterized in that, The foundation piles include a first foundation pile and a second foundation pile. The step of setting multiple foundation piles around the circumference of the wellhead of the deep vertical shaft includes: Multiple first foundation piles are arranged around the circumference of the wellhead of the deep vertical shaft, and the multiple first foundation piles are arranged at intervals along the circumference of the deep vertical shaft; Multiple second foundation piles are installed around the circumference of the opening of the deep vertical shaft, and the first foundation piles and the second foundation piles are arranged alternately around the circumference of the deep vertical shaft.

3. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 2, characterized in that, The cross-sections of the second foundation pile and the adjacent first foundation pile partially overlap.

4. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 3, characterized in that, The arrangement of multiple first foundation piles around the circumference of the wellhead of the deep vertical shaft includes: Multiple first holes are opened around the circumference of the wellhead of the deep vertical shaft; A first reinforcing cage coaxial with the first hole is placed into each first hole; Concrete is injected into the first hole.

5. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 4, characterized in that, The arrangement of multiple second foundation piles around the circumference of the wellhead of the deep vertical shaft includes: Multiple second holes are opened around the circumference of the wellhead of the deep vertical shaft; A second reinforcing cage coaxial with the second hole is placed in each second hole, and the outer periphery of the second reinforcing cage is tangent to the outer periphery of the adjacent first hole, so that the two sides of the second hole coincide with the cross-sectional portion of the adjacent first hole respectively. Concrete is injected into the second hole.

6. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 5, characterized in that, Once the first foundation pile has reached 70% solidification, the second foundation pile is installed.

7. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 6, characterized in that, The procedure prior to placing a reinforcing cage coaxial with the first hole into each of the first holes includes: A first positioning element is installed at the opening of the first hole; One end of the first reinforcing cage and the first positioning member can move radially along the first hole, while the other end abuts against the bottom wall of the first hole; The first reinforcing cage is moved radially along the first hole so that the first reinforcing cage is coaxially arranged with the first hole.

8. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 1, characterized in that, The step of pulling the deep shaft back from the bottom to the opening along the inner side profile of the shaft using a cutter also includes: Multiple anchor bolt assemblies are arranged circumferentially around the deep shaft, such that one end of each anchor bolt assembly is connected to the foundation pile and the other end is fixed to the ground.

9. The method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft according to claim 8, characterized in that, The angle between the anchor bolt assembly and the axis of the deep shaft is set to 15°-25°.

10. A device for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft, formed by the method for reinforcing strongly weathered rock strata at the wellhead of a deep vertical shaft as described in any one of claims 1-9, characterized in that, The surface strongly weathered rock layer reinforcement device at the wellhead of the deep vertical shaft includes: Multiple foundation piles are arranged around the circumference of the wellhead of the deep vertical shaft, and the cross sections of two adjacent foundation piles have overlapping areas.

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