A detachable near-spiral staircase structure for deep and narrow vertical shafts and its construction method

Abstract

This invention provides a detachable near-spiral staircase structure for deep and narrow vertical shafts, comprising multiple staircase components sequentially assembled from the shaft opening to the bottom, forming a roughly spiral shape. These staircase components are constructed section by section as the shaft is excavated. Corresponding to each staircase component, multiple sets of spaced support frames are installed on the shaft wall according to the length and slope of the staircase component to support it. Each support frame has a pair of adjustable supports, and the ladder beams are detachably connected to the support frames via these adjustable supports. A corner area is formed between the joint of adjacent staircase components and the shaft wall, and adjacent staircase components are fixedly connected at the corner area via a horizontally positioned corner platform. Each staircase component has guardrails on both sides of the ladder beams, and steps are provided between the two sides of the ladder beams. This invention can improve construction efficiency while reducing construction costs.

Description

Technical Field

[0001] This invention relates to a vertical shaft staircase, and more specifically to a detachable near-spiral staircase structure and construction method for deep and narrow vertical shafts. Background Technology

[0002] Vertical shafts are well-shaped pipes with upright walls. They are actually a type of collapse funnel. In terms of planar outline, they are square, long strip, or irregularly circular. Long strips develop along one set of joints, while square or circular ones develop along two sets of joints. The shaft walls are steep and almost vertical. Sometimes, the surface of an underground river can be seen from the shaft.

[0003] During the excavation of shafts, staircases are typically required for workers to walk on. However, existing staircases, lacking spiral staircases, can only utilize prefabricated ladder cages or vertical ladders. Since vertical ladders are suitable for shafts no deeper than 20 meters, and Chongqing Metro shafts often reach depths of 40-50 meters, their use is unsafe. Therefore, the current solution is to use prefabricated ladder cages, but these cages, measuring 2.988m × 1.78m × 2m, are very space-consuming.

[0004] Furthermore, since prefabricated ladder cages can only be installed at the corners of shafts, and there are horizontal diagonal braces at the corners, the prefabricated ladder cages need to be installed outside of the diagonal braces, which takes up more space. In urban centers, mechanical excavation is generally used for construction. The working radius of a 485 excavator is about 6 meters. If prefabricated ladder cages are used, it will greatly affect the construction of shafts, especially narrow shafts.

[0005] Therefore, existing staircases have the following drawbacks during use:

[0006] 1. Impact on construction efficiency: If conventional prefabricated ladder cages are used, in order not to affect the construction of the working surface, the bottom prefabricated ladder cage must be about 3 meters above the construction horizontal working surface (3 meters suspended), and a certain space must be left for normal construction work. The remaining 3 meters need to be installed with vertical ladder cages. This method of personnel transportation greatly reduces efficiency. In addition, the prefabricated ladder cages must be installed by specialized installation personnel, which will also affect construction efficiency.

[0007] 2. The cost is relatively high; the cost of prefabricated ladder cages is higher, and they require certified personnel from specialized manufacturers for installation, which increases the cost.

[0008] 3. High physical exertion for workers: The use of prefabricated ladder cages, due to their small turning radius, places high demands on the physical strength of workers in deeper shafts, making it difficult for workers to enter deep shafts for work. Therefore, the existing ladders still have certain limitations in use. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention proposes a detachable near-spiral staircase structure for deep and narrow vertical shafts and its construction method, which can improve construction efficiency while reducing construction costs.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A deep and narrow vertical shaft detachable near-spiral staircase structure, characterized by the following features:

[0012] It consists of multiple sections of a staircase assembly that are attached to the walls of the vertical shaft, sequentially spliced ​​from the shaft opening to the bottom of the shaft, and arranged in a roughly spiral shape as a whole.

[0013] The multi-section staircase assembly is constructed section by section as the shaft is excavated. Corresponding to each staircase assembly, multiple sets of spaced support frames are installed on the shaft wall according to the length and slope of the assembly to support it. Each support frame includes a first H-beam, a second H-beam, and a first connector. The first H-beam is horizontally positioned, with one end anchored into the rock mass of the shaft wall to a depth of 500mm and reinforced with concrete. The exposed section at the bottom is diagonally supported by the second H-beam. The lower end of the second H-beam is anchored into the rock mass and reinforced with concrete, while the higher end is detachably connected to the first H-beam via the first connector. Each support frame is equipped with a pair of adjustable supports, which respectively fix the staircase assembly. The ladder beams are arranged on both sides. The adjustable support includes a base, a support, a screw, double nuts, a connecting plate, and reinforcing ribs. The base is fixed to the top of the first I-beam. The support is fixed on the base, and multiple reinforcing ribs are provided between the base and the support. The lower end of the screw is inserted into a pre-drilled screw hole on the support and can be tightened by the double nuts. The upper end is fixed to support the connecting plate. The height of the connecting plate is adjustable by the screw. The upper plate surface is parallel to the ladder beam. The bottom end of the ladder beam is fixed with a transition plate corresponding to the support position of the adjustable support. The transition plate is in close contact with the upper plate surface of the connecting plate. Multiple through bolt holes are pre-drilled on both plates. Bolts are used to tighten the ladder beam and the support frame through the adjustable support.

[0014] A corner area is formed between the connection point of two adjacent staircase sections and the shaft wall. The two adjacent staircase sections are fixedly connected at the corner area by a corner platform, which is horizontally set. Each staircase section has a staircase railing on both sides of the stair beams, and steps are set between the two side stair beams.

[0015] The structural features of this invention also lie in:

[0016] The first connector includes a pair of first connecting steel plates with multiple threaded holes and multiple first bolts adapted to each threaded hole. At the junction of the first I-beam and the second I-beam, a first connecting steel plate is welded to the bottom end of the first I-beam and the top end of the second I-beam respectively. The pair of first connecting steel plates are fastened together at the aligned threaded holes by first bolts to form a detachable connection between the first I-beam and the second I-beam.

[0017] The first and second I-beams are made of I-beams used for initial support of the shaft.

[0018] Within a depth of 500mm where the first I-beam is anchored into the rock mass, it is reinforced with concrete of the same grade as the initial support of the shaft.

[0019] The corner platform includes a connecting channel steel, a second connecting steel plate, and a second bolt. It is set in the corner area and connected between two adjacent staircase assemblies. The outer frame is made of multiple connecting channel steel sections. A horizontal platform steel plate is laid inside the outer frame corresponding to the corner area. It is connected to the stair beams of the two adjacent staircase assemblies through the connecting channel steel. A second connecting steel plate is provided at the connection point. The second connecting steel plate is fastened to the connecting channel steel and the corresponding stair beam by the second bolt.

[0020] Each staircase assembly has multiple steps sequentially installed between the two side stair beams from top to bottom. Each step consists of a tread and a step, with a tread width of 240mm and a step height of 200mm.

[0021] In each step assembly, the outer side of the single-sided ladder beam has multiple holes reserved for the step railing on that side. The multiple posts and handrails of the step railing are made of seamless steel pipes, and the reinforcing bars between the multiple posts are made of threaded steel. The step railing is inserted into each hole in a matching manner through the posts.

[0022] The vertical shaft has a rectangular cross-sectional profile, and each step ladder assembly is attached to the shaft wall and spirals down along the four sides of the shaft wall from the shaft opening to the bottom of the shaft.

[0023] This invention also proposes a construction method for a detachable near-spiral staircase structure for deep and narrow vertical shafts, which is used to construct the aforementioned detachable near-spiral staircase structure for deep and narrow vertical shafts. The method is implemented according to the following steps:

[0024] Step 1: As the shaft is excavated, each section of the staircase assembly is constructed section by section. When constructing each staircase assembly, first mark the elevation positions of each set of support frames on the corresponding wall surface of the shaft according to the slope ratio and length of the staircase assembly. Drill holes at the elevation positions for anchoring the first and second I-beams. At each elevation position, anchor the first and second I-beams into the drilled holes. Within the depth range of the holes, reinforce with the same grade of concrete as the initial shaft support. Then, assemble the first and second I-beams using the first connector to complete the installation of the support frame.

[0025] Step 2: Complete the assembly of the stair beams and steps outside the shaft, and complete the assembly of the stair railings;

[0026] Step 3: Weld and assemble the base, support, and reinforcing rib of the adjustable support. Weld and assemble the connecting plate and screw rod of the adjustable support. Before assembly, adjust the inclination angle of the connecting plate according to the slope ratio of the stair assembly so that it can be parallel to the stair beam. According to the position of the stair beams on both sides, distribute the base, support, and reinforcing rib of a pair of adjustable supports on each set of support frames. Weld the base, support, and reinforcing rib of a pair of adjustable supports to the first I-beam through the base. Then assemble the connecting plate and the transition plate on the stair beam with bolts. After that, use hoisting equipment above the shaft to hoist the assembled stair beam and the steps into the shaft so that the stair beam is above the support in the corresponding adjustable support. Align the screw rods suspended at the bottom of the stair beam with the screw holes on the support directly below and screw them in. Adjust the stair beam according to the slope ratio of the stair assembly. Then use double nuts to keep the screw rods fixed on the support. This completes the installation of the stair beam and the steps.

[0027] Step 4: After completing the installation of the ladder beams and steps, use hoisting equipment to lift the ladder railing into the shaft, so that the posts of the ladder railing are inserted into the pre-drilled holes on the outside of the ladder beams. This completes the installation of one section of the ladder assembly.

[0028] Step 5: Referring to steps 1-4, install each section of the staircase assembly sequentially as the shaft continues to be excavated. When installing each subsequent section of the staircase assembly, connect its ladder beam to the ladder beam of the previous section via the corner platform. First, based on the external dimensions of the corner area and the position distribution of the ladder beams of adjacent staircase assemblies, assemble the outer frame of the corner platform using connecting channel steel. Place the outer frame into the corner area. The outer frame is then connected to the end of the ladder beam of the previous section of the staircase assembly via the adjacent connecting channel steel and the second connecting steel plate, and secured with the second bolt. After the ladder beam of the next section of the staircase assembly is erected, connect the outer frame to the beginning of the ladder beam of the next section of the staircase assembly via the adjacent connecting channel steel and the second connecting steel plate, and secure with the second bolt. Corresponding to each second bolt, there are pre-drilled bolt holes on the ladder beam, connecting channel steel, and second connecting steel plate.

[0029] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0030] 1. The present invention provides a new approach and effective solution for vertical shaft staircases, which is applicable to vertical shafts of various depths, and combines convenience and economy, breaking through the technical bottleneck of only being able to use vertical ladders or prefabricated ladder cages at the current stage.

[0031] Because this invention is made by splicing together multiple sections of staircase components attached to the shaft wall, sequentially spliced ​​from the shaft opening to the bottom of the shaft, and arranged in a roughly spiral shape, it occupies less space on one side of the shaft wall and can be directly installed on the shaft wall without occupying a large area of ​​the existing shaft construction surface. This staircase structure can be constructed section by section as the shaft is excavated, with the support frame and ladder beams constructed at the excavation layer, facilitating the movement of workers, providing convenience for construction, improving construction efficiency, and the frame of the support frame can be made of I-beams used for the initial support of the shaft. Within the depth range of anchoring into the rock mass, it can be reinforced with concrete of the same grade as the initial support of the shaft. The materials are easy to obtain, which helps to control construction costs.

[0032] 2. Installation is more convenient and efficient, shortening construction time and reducing construction difficulty;

[0033] In this invention, the staircase assembly is supported by a support frame anchored into the rock mass. It is detachably assembled with the support frame via an adjustable support. The adjustable support provides an adjustable margin for the installation of the staircase assembly, which greatly reduces the construction difficulty, simplifies the construction operation, and makes the installation of the staircase assembly convenient and efficient.

[0034] 3. Better results when used;

[0035] The present invention adopts a near-spiral distribution form with a larger turning radius. Compared with vertical ladders or prefabricated ladder cages, the slope of the steps is gentler, the physical exertion of the workers is less, and it is more conducive to the subsequent construction work. Attached Figure Description

[0036] Figure 1 This is a top view of the structure of the present invention within a vertical shaft;

[0037] Figure 2 This is a schematic diagram of the main structure of the present invention within a vertical shaft;

[0038] Figure 3 This is a structural diagram of the support frame;

[0039] Figure 4 This is a schematic diagram showing the positional relationship between the ladder beam and the adjustable support;

[0040] Figure 5 This is a structural schematic diagram of the transition plate attached to the ladder beam;

[0041] Figure 6 This is a schematic diagram of the adjustable support structure;

[0042] Figure 7 This is a schematic diagram of the assembly structure of the stair beams and the stair railings;

[0043] Figure 8 This is a structural diagram of the stair railing;

[0044] Figure 9 This is a schematic diagram of the connection structure between the channel steel and the ladder beam.

[0045] In the picture:

[0046] 1. Rock mass;

[0047] 2. Staircase assembly; 21. Stair beam; 211. Insert; 212. Adapter plate; 22. Step; 23. Staircase railing; 231. Post; 232. Handrail; 233. Reinforcing bar;

[0048] 3. Corner platform; 31. Connecting channel steel; 311. Bending section; 32. Second connecting steel plate; 33. Second bolt;

[0049] 4. Support frame; 41. First I-beam; 42. Second I-beam; 43. First connecting steel plate; 44. First bolt;

[0050] 5 Adjustable support; 51 Base; 52 Support; 53 Screw; 54 Double nut; 55 Connecting plate; 56 Reinforcing rib. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0052] Please refer to Figures 1 to 9 The deep and narrow vertical shaft detachable near-spiral staircase structure of this embodiment is configured as follows:

[0053] It consists of multiple sections of a staircase assembly 2 that are attached to the walls of the vertical shaft, sequentially spliced ​​from the shaft opening to the bottom of the shaft, and arranged in a roughly spiral shape as a whole.

[0054] The multi-section staircase assembly 2 is constructed section by section as the shaft is excavated. Corresponding to each section of the staircase assembly 2, multiple sets of spaced support frames 4 are installed on the shaft wall according to the length and slope ratio of the staircase assembly 2 to support it. Each support frame 4 includes a first I-beam 41, a second I-beam 42, and a first connector. The first I-beam 41 is horizontally positioned, with one end anchored into the rock mass 1 of the shaft wall to a depth of 500mm and reinforced with concrete. The exposed section is supported at the bottom by the second I-beam 42, whose lower end is anchored into the rock mass 1 and reinforced with concrete. The higher end is detachably connected to the first I-beam 41 via the first connector. Each support frame 4 is equipped with a pair of adjustable supports 5, which respectively fix the two side beams 21 supporting the staircase assembly 2. Each adjustable support 5 includes a base. 51, support 52, screw 53, double nut 54, connecting plate 55, and reinforcing rib 56 are fixed to the top of the first I-beam 41 via the base 51. The support 52 is fixed on the base 51, and multiple reinforcing ribs 56 are provided between the base 51 and the support 52. The lower end of the screw 53 is inserted into the screw hole reserved on the support 52 and can be tightened by the double nut 54. The upper end is fixed to the supporting connecting plate 55. The height of the connecting plate 55 is adjustable by the screw 53. The upper plate surface is parallel to the ladder beam 21. The bottom end of the ladder beam 21 is fixed with the transition plate 212 at the support position of the adjustable support 5. The transition plate 212 is in close contact with the upper plate surface of the connecting plate 55. Multiple bolt holes are reserved on the two plates. Bolts are used to tighten the ladder beam 21 and the support frame 4 through the adjustable support 5.

[0055] A corner area is formed between the connection point of two adjacent staircase components 2 and the wall of the shaft. The two adjacent staircase components 2 are fixedly connected at the corner area by a corner platform, which is set horizontally. Each staircase component 2 has a staircase railing 23 on both sides of the stair beam 21, and a step 22 is provided between the two sides of the stair beam 21.

[0056] In practice, the corresponding structural features of this staircase structure also include:

[0057] In the adjustable support 5, the connecting plate 55 is 200mm wide.

[0058] The first connecting component includes a pair of first connecting steel plates 43 with multiple threaded holes and multiple first bolts 44 adapted to each threaded hole. At the junction of the first I-beam 41 and the second I-beam 42, a first connecting steel plate 43 is welded to the bottom end of the first I-beam 41 and the top end of the second I-beam 42, respectively. The pair of first connecting steel plates 43 are fastened together at the aligned threaded holes by the first bolts 44, forming a detachable connection between the first I-beam 41 and the second I-beam 42. The first connecting steel plate 43 is 10mm thick and 200mm long and wide. The first I-beam 41, the second I-beam 42 and the corresponding first connecting steel plate 43 are connected by full welding around the perimeter. The threaded hole specification is A24, and the first bolts 44 are 8.8 grade ordinary bolts M22×80mm.

[0059] The first I-beam 41 and the second I-beam 42 are made of I-beams used for the initial support of the shaft. The profiles are readily available, which further facilitates the construction. Using I-beams as the skeleton of the support frame 4 can ensure the safety of the staircase. At the same time, they are inexpensive and help reduce construction costs.

[0060] The first I-beam 41 is anchored into the rock mass to a depth of 1500mm and reinforced with concrete of the same grade as the initial support of the shaft.

[0061] The corner platform 3 includes a connecting channel steel 31, a second connecting steel plate 32, and a second bolt 33. It is located in the corner area and connects to adjacent staircase sections. The outer frame is made of multiple connecting channel steel sections. A horizontal platform steel plate is laid within the outer frame corresponding to the corner area. It is connected to the stair beams of adjacent staircase sections via the connecting channel steel. A second connecting steel plate is provided at the connection point, and the second connecting steel plate is fastened to the connecting channel steel and the corresponding stair beam using the second bolt. The second connecting steel plate is 10mm thick and 200mm long and wide.

[0062] Each staircase assembly 2 has multiple steps 22 sequentially installed between the two side stair beams 21 from top to bottom. Each step 22 consists of treads and steps, with a clear width of 750mm, a step width of 240mm, and a step height of 200mm. The steps 22 are made of 2mm thick Q235 hot-rolled anti-slip patterned steel plate.

[0063] In each step assembly 2, the outer side of the single-sided ladder beam 21 has multiple pre-drilled holes 211 for the side step railing 23. The multiple posts 231 and handrails 232 of the step railing 23 are made of A42mm seamless steel pipes. The reinforcing bars 233 between the multiple posts 231 are made of C12 threaded steel. The step railing 23 is inserted into each hole 211 in a matching manner through the posts 231.

[0064] The vertical shaft has a rectangular cross-section, such as a vertical shaft with a length and width of 18m×12m, 10m×10m, or 12m×4m. Each section of the staircase assembly 2 is attached to the vertical shaft wall and spirals down along the four sides of the vertical shaft wall from the shaft opening to the bottom of the shaft.

[0065] The ladder beam 21 is made of channel steel. Corresponding to the long side of the shaft wall, the ladder beam 21 of the attached stair assembly 2 is made of Q23516a channel steel with a length of 3150mm; corresponding to the short side of the shaft wall, the ladder beam 21 of the attached stair assembly 2 is 1500mm long and is made of Q23516a channel steel with a length of 1570mm. The elevations of each ladder beam assembly are as follows... Figure 2 As shown. The upper end of the first ladder beam overlaps to the height of the retaining wall at the shaft opening, i.e. Figure 2 The winning bid was 324.844.

[0066] This invention also proposes a construction method for a detachable near-spiral staircase structure in deep and narrow vertical shafts, used for constructing the aforementioned detachable near-spiral staircase structure in deep and narrow vertical shafts, implemented according to the following steps:

[0067] Step 1: As the shaft is excavated, each section of the staircase assembly 2 is constructed section by section. When constructing each section of the staircase assembly 2, firstly, according to the slope ratio and length of the staircase assembly 2, mark the elevation positions of the corresponding support frame 4 on the corresponding wall surface of the shaft. Drill holes at the elevation positions for anchoring the first I-beam 41 and the second I-beam 42. At each elevation position, anchor the first I-beam 41 and the second I-beam 42 into the drilled holes. Within the depth range of the holes, reinforce with the same grade of initial shaft support concrete. Then, assemble the first I-beam 41 and the second I-beam 42 through the first connector to complete the installation of the support frame 4.

[0068] Step 2: Complete the assembly of the ladder beam 21 and the step 22 outside the shaft, and complete the assembly of the stair railing 23;

[0069] Step 3: Weld and assemble the base 51, support 52, and reinforcing rib 56 of the adjustable support 5. Weld and assemble the connecting plate 55 and screw 53 of the adjustable support 5. Before assembly, adjust the inclination angle of the upper surface of the connecting plate 55 according to the slope ratio of the stair assembly 2 so that it can be parallel to the stair beam 21. According to the position of the stair beams 21 on both sides, distribute them on each set of support frame 4. Weld the base 51, support 52, and reinforcing rib 56 of a pair of adjustable supports 5 to the first I-beam 41 through the base 51. Then connect the connecting plate 55 to the stair beam. The adapter plate 212 on 21 is assembled with bolts. Then, the assembled ladder beam 21 and step 22 are hoisted into the shaft using hoisting equipment above the shaft, so that the ladder beam 21 is positioned above the support 52 in the corresponding adjustable support 5. The screws 53 suspended at the bottom of the ladder beam 21 are aligned with the screw holes on the support 52 directly below and screwed in. The ladder beam 21 is adjusted according to the slope ratio of the step assembly 2. Then, the screws 53 are fixed on the support 52 using double nuts 54. The installation of the ladder beam 21 and step 22 is thus completed.

[0070] Step 4: After completing the installation of the ladder beam 21 and the step 22, the ladder railing 23 is hoisted into the shaft using hoisting equipment, so that the uprights 231 of the ladder railing 23 are inserted into the pre-reserved holes 211 on the outside of the ladder beam 21. This completes the installation of one section of ladder assembly 2.

[0071] Step 5: Referring to steps 1-4, install each section of the staircase assembly sequentially as the shaft continues to be excavated. When installing each subsequent section of the staircase assembly, connect its ladder beam to the ladder beam of the previous section of the staircase assembly via the corner platform 3. First, based on the external dimensions of the corner area and the position distribution of the ladder beams of the adjacent two sections of the staircase assembly, assemble the outer frame of the corner platform 3 using connecting channel steel 31. Place the outer frame into the corner area. The outer frame is first spliced ​​to the end of the ladder beam of the previous section of the staircase assembly via the adjacent connecting channel steel 31 and the second connecting steel plate 32, and then secured with the second bolt 33. After the ladder beam of the next section of the staircase assembly is erected, the outer frame is then spliced ​​to the beginning of the ladder beam of the next section of the staircase assembly via the adjacent connecting channel steel 31 and the second connecting steel plate 32, and then secured with the second bolt 33. Corresponding to each second bolt 33, there are pre-drilled bolt holes on the ladder beam, connecting channel steel 31, and second connecting steel plate 32.

[0072] In step 5 above, among the connecting channel steels 31 that make up the outer frame of the corner platform 3, the connecting channel steel 31 used to connect with the ladder beam of the preceding or following stair assembly forms a bent section 311 along the direction of the corresponding ladder beam. This bent section is then spliced ​​with the corresponding ladder beam, and the splice is secured at the joint using a second connecting steel plate 32 and a second bolt 33. Except for the bent section, the remaining parts of the connecting channel steel 31 are horizontally arranged. The number of connecting channel steels 31 at each corner platform 3 is not uniformly required; the principle is to ensure a stable connection between adjacent stair assemblies, allowing for flexible erection. After the outer frame is erected, the platform steel plate is laid and welded firmly to the outer frame.

[0073] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A detachable near-spiral staircase structure for deep and narrow vertical shafts, characterized in that: It consists of multiple sections of a staircase assembly that are attached to the walls of the vertical shaft, sequentially spliced ​​from the shaft opening to the bottom of the shaft, and spiraled downwards as a whole. The multi-section staircase assembly is constructed section by section as the shaft is excavated. Corresponding to each staircase assembly, multiple sets of spaced support frames are installed on the shaft wall according to the length and slope ratio of the staircase assembly to support it. Each support frame includes a first H-beam, a second H-beam, and a first connector. The first H-beam is horizontally positioned, with one end anchored into the rock mass of the shaft wall to a depth of 500mm and reinforced with concrete. The exposed section at the bottom is diagonally supported by the second H-beam. The lower end of the second H-beam is anchored into the rock mass and reinforced with concrete, while the higher end is detachably connected to the first H-beam via the first connector. Each support frame has a pair of adjustable supports, which respectively fix the two side beams supporting the staircase assembly. The adjustable supports include a base... The system comprises a base, a support, a screw, double nuts, a connecting plate, and reinforcing ribs, all fixed to the top of the first I-beam via a base. The support is fixed to the base, with multiple reinforcing ribs between it and the base. The lower end of the screw is inserted into a pre-drilled hole in the support and secured by double nuts. The upper end of the screw supports the connecting plate, the height of which is adjustable via the screw. The upper plate surface is parallel to the ladder beam. A transition plate is fixed to the bottom of the ladder beam at the position corresponding to the adjustable support. The transition plate is in close contact with the upper plate surface of the connecting plate. Multiple through bolt holes are pre-drilled on both plates, and bolts are used to secure the ladder beam to the support frame via the adjustable support. The first and second I-beams are made of I-beams used for initial shaft support. A corner area is formed between the connection point of two adjacent staircase sections and the shaft wall. The two adjacent staircase sections are fixedly connected at the corner area by a corner platform, which is horizontally set. Each staircase section has a staircase railing on both sides of the stair beams, and steps are set between the two side stair beams.

2. The deep and narrow vertical shaft detachable near-spiral staircase structure according to claim 1, characterized in that: The first connector includes a pair of first connecting steel plates with multiple threaded holes and multiple first bolts adapted to each threaded hole. At the junction of the first I-beam and the second I-beam, a first connecting steel plate is welded to the bottom end of the first I-beam and the top end of the second I-beam respectively. The pair of first connecting steel plates are fastened together at the aligned threaded holes by first bolts to form a detachable connection between the first I-beam and the second I-beam.

3. The deep and narrow vertical shaft detachable near-spiral staircase structure according to claim 1, characterized in that: Within a depth of 500mm where the first I-beam is anchored into the rock mass, it is reinforced with concrete of the same grade as the initial support of the shaft.

4. The deep and narrow vertical shaft detachable near-spiral staircase structure according to claim 1, characterized in that: The corner platform includes a connecting channel steel, a second connecting steel plate, and a second bolt. It is set in the corner area and connected between two adjacent staircase assemblies. The outer frame is made of multiple connecting channel steel sections. A horizontal platform steel plate is laid inside the outer frame corresponding to the corner area. It is connected to the stair beams of the two adjacent staircase assemblies through the connecting channel steel. A second connecting steel plate is provided at the connection point. The second connecting steel plate is fastened to the connecting channel steel and the corresponding stair beam by the second bolt.

5. The deep and narrow vertical shaft detachable near-spiral staircase structure according to claim 1, characterized in that: Each staircase assembly has multiple steps sequentially installed between the two side stair beams from top to bottom. Each step consists of a tread and a step, with a tread width of 240mm and a step height of 200mm.

6. The deep and narrow vertical shaft detachable near-spiral staircase structure according to claim 1, characterized in that: In each step assembly, the outer side of the single-sided ladder beam has multiple holes reserved for the step railing on that side. The multiple posts and handrails of the step railing are made of seamless steel pipes, and the reinforcing bars between the multiple posts are made of threaded steel. The step railing is inserted into each hole in a matching manner through the posts.

7. The deep and narrow vertical shaft detachable near-spiral staircase structure according to claim 1, characterized in that: The vertical shaft has a rectangular cross-sectional profile, and each step ladder assembly is attached to the shaft wall and spirals down along the four sides of the shaft wall from the shaft opening to the bottom of the shaft.

8. A construction method for a deep and narrow vertical shaft detachable near-spiral staircase structure, used for constructing the deep and narrow vertical shaft detachable near-spiral staircase structure as described in any one of claims 1-7, characterized in that, Follow these steps: Step 1: As the shaft is excavated, each section of the staircase assembly is constructed section by section. When constructing each staircase assembly, first mark the elevation positions of each set of support frames on the corresponding wall surface of the shaft according to the slope ratio and length of the staircase assembly. Drill holes at the elevation positions for anchoring the first and second I-beams. At each elevation position, anchor the first and second I-beams into the drilled holes. Within the depth range of the holes, reinforce with the same grade of concrete as the initial shaft support. Then, assemble the first and second I-beams using the first connector to complete the installation of the support frame. Step 2: Complete the assembly of the stair beams and steps outside the shaft, and complete the assembly of the stair railings; Step 3: Weld and assemble the base, support, and reinforcing rib of the adjustable support. Weld and assemble the connecting plate and screw rod of the adjustable support. Before assembly, adjust the inclination angle of the connecting plate according to the slope ratio of the stair assembly so that it can be parallel to the stair beam. According to the position of the stair beams on both sides, distribute the base, support, and reinforcing rib of a pair of adjustable supports on each set of support frames. Weld the base, support, and reinforcing rib of a pair of adjustable supports to the first I-beam through the base. Then assemble the connecting plate and the transition plate on the stair beam with bolts. After that, use hoisting equipment above the shaft to hoist the assembled stair beam and the steps into the shaft so that the stair beam is above the support in the corresponding adjustable support. Align the screw rods suspended at the bottom of the stair beam with the screw holes on the support directly below and screw them in. Adjust the stair beam according to the slope ratio of the stair assembly. Then use double nuts to keep the screw rods fixed on the support. This completes the installation of the stair beam and the steps. Step 4: After completing the installation of the ladder beams and steps, use hoisting equipment to lift the ladder railing into the shaft, so that the posts of the ladder railing are inserted into the pre-drilled holes on the outside of the ladder beams. This completes the installation of one section of the ladder assembly. Step 5: Referring to steps 1-4, install each section of the staircase assembly sequentially as the shaft continues to be excavated. When installing each subsequent section of the staircase assembly, connect its ladder beam to the ladder beam of the previous section via the corner platform. First, based on the external dimensions of the corner area and the position distribution of the ladder beams of adjacent staircase assemblies, assemble the outer frame of the corner platform using connecting channel steel. Place the outer frame into the corner area. The outer frame is then connected to the end of the ladder beam of the previous section of the staircase assembly via the adjacent connecting channel steel and the second connecting steel plate, and secured with the second bolt. After the ladder beam of the next section of the staircase assembly is erected, connect the outer frame to the beginning of the ladder beam of the next section of the staircase assembly via the adjacent connecting channel steel and the second connecting steel plate, and secure with the second bolt. Corresponding to each second bolt, there are pre-drilled bolt holes on the ladder beam, connecting channel steel, and second connecting steel plate.

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