Underground space single-arch double-column umbrella-shaped supporting structure and underground space underground excavation construction method

Abstract

The invention discloses an underground space single-arch double-column umbrella-shaped supporting structure and an underground excavation construction method. The underground space single-arch double-column umbrella-shaped supporting structure comprises a top arch, a top longitudinal beam, a bottom arch, a bottom longitudinal beam, a plurality of rows of stand columns and a reverse middle plate arranged between the top arch and the bottom arch. Partial side plates belonging to the underground space are arranged between the two sides of the reverse middle plate and the two sides of the top arch. Primary support structures are arranged on the side plates of the underground space above the reverse middle plate and the upper surface of the top arch; arch foot longitudinal beams are arranged on the two side edges of the top arch; pilot tunnels are independently formed in the structure from the middle plate to the top arch and the connecting position of each row of stand columns and the bottom arch for construction; the pilot tunnel of each stand column from construction of the reverse construction middle plate to the top arch is constructed to the pilot tunnel of the connection position of the corresponding stand column and the bottom arch through manual hole digging piles. According to the method, the problems that arching is difficult through a single-arch arch cover method under the shallow soil covering stratum condition, a middle stand column node in a double-arch single-column arch cover method is prone to instability, and water is prone to accumulating in a V-shaped node can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of underground space construction, and in particular to an underground space single-arch double-column umbrella-shaped support structure and an underground space dark excavation construction method. Background Art

[0002] With the development of rail transit construction, various complex demands are increasing, and the demand for large-section subway stations is also increasing. The use of conventional open-cut construction methods to build underground stations often requires traffic diversion and pipeline relocation, which will also have a significant impact on the surrounding environment. Therefore, for central urban areas with complex surrounding environments, the use of concealed excavation methods to build underground stations has become an urgent need. The advantage of concealed excavation is that it can avoid affecting surface traffic, underground pipelines and surrounding structures; however, due to the generally slow construction speed of concealed excavation methods, concealed excavation stations often become key nodes that restrict the construction period of the entire line. Therefore, choosing a construction method that matches the construction conditions of the project is crucial to improving construction efficiency, thereby saving construction time and improving the quality of the project.

[0003] Current status of related technologies in this field:

[0004] 1) Single arch cover method

[0005] The single-arch arch-capping method is commonly used for the construction of large-section subway stations. This method, based on the open-cut, cover-cut, and PBA methods, is a new, underground excavation method suitable for most strata. This method leverages the bearing capacity and stability of the underlying rock mass, constructing the arch cap with minimal or no blasting. The arch cap rests on stable bedrock at both ends, forming large arch feet.

[0006] (1) The main construction steps of the single arch cover method are: ① When excavating the upper section, the large-span single arch section pilot tunnel is excavated and temporary supports are set up; ② After the arch cover is constructed, the lower section is excavated by slope cutting and grooving.

[0007] (2) Compared with other underground excavation methods, the main features of the single arch cover method are:

[0008] a) After the arch cover is completed, the working space is large, large-scale machinery can be used for construction, construction interference is small, and construction difficulty is low;

[0009] b) After the arch cover is formed, the excavation speed of the lower soil can be accelerated, and the overall construction progress is fast;

[0010] c) There are fewer conversions in the later stages of the process, less temporary support removal, and less abandoned projects.

[0011] (3) However, the single arch cover method also has certain defects:

[0012] a) For large-span shallow-buried underground excavation subway stations, due to the large span, it is difficult to use a single arch to form the arch, and the ground settlement is difficult to control.

[0013] b) The horizontal thrust of the arch foot is large, so the arch foot needs to be expanded outward and a concrete foundation cast to increase the horizontal and vertical bearing capacity.

[0014] 2) Multi-arch covering method

[0015] In order to reduce ground settlement during the construction of the single arch cap method, the large section is decomposed into multiple arch structures, and the middle support adopts the top and bottom longitudinal beams plus steel pipe column support system (see Figure 1 ). At present, the double-arch and single-column arch cover method is mainly used in engineering projects.

[0016] (1) The main construction steps of the double-arch single-column arch capping method are as follows: ① First, construct the upper and lower pilot holes, manually dig a hole between the upper and lower pilot holes, then construct the bottom longitudinal beam, install the steel tube concrete column, and then construct the top longitudinal beam. Together with the top side pilot hole longitudinal beam constructed simultaneously, it forms the fulcrum for the buckle arch construction. ② After the complete arch cap is formed, the lower half section is excavated by slope cutting and grooving.

[0017] (2) The main features of the double-arch single-column arch cover method are:

[0018] Taking the double-arch single-column arch cover method as an example, since each small arch itself has horizontal thrust, in order to transfer the horizontal thrust of the side arch foot to the foundation, it is generally necessary to excavate a small pilot hole separately to set up the expanded arch foot longitudinal beam. After completion, the over-excavation part needs to be backfilled with plain concrete.

[0019] (3) The double-arch single-column arch cover method also has certain defects:

[0020] a) The middle column node is not conducive to the stress of a single arch, so the single arches on both sides need to be constructed symmetrically. Improper handling may easily cause instability.

[0021] b) The horizontal thrust of the arch foot is large, so the arch foot needs to be expanded outward and a concrete foundation cast to increase the horizontal bearing capacity.

[0022] c) There is a "V"-shaped node at the top of the middle column, which is prone to water accumulation.

[0023] Therefore, under the premise of tight construction period, strict environmental restrictions and strict waterproofing quality requirements, how to make it adapt to shallow buried conditions safely and efficiently has become a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0024] In view of the above-mentioned defects of the prior art, the present invention provides an underground space single-arch double-column umbrella-shaped support structure and an underground space dark excavation construction method, the purpose of which is to solve the problem of difficulty in forming an arch by the single-arch arch covering method without an intermediate column under shallow covering soil conditions, as well as the problem of easy instability of the intermediate column nodes and easy water accumulation in the "V"-shaped nodes of the double-arch single-column arch covering method.

[0025] To achieve the above-mentioned objectives, the present invention discloses a single-arch, double-column umbrella-shaped support structure for an underground space, comprising a top arch extending along the length of the underground space and arching upward in cross section, at least two top longitudinal beams disposed on the lower surface of the top arch, bottom longitudinal beams disposed above the bottom arch of the underground space and corresponding one-to-one with the top longitudinal beams, multiple rows of columns disposed between each top longitudinal beam and the corresponding bottom longitudinal beam, and a reverse-worked center plate disposed between the top arch and the bottom arch;

[0026] Partial side panels belonging to the underground space are provided between both sides of the top arch and both sides of the top arch;

[0027] The side panels of the underground space above the top plate and the upper surface of the top arch are provided with an initial support structure;

[0028] Both sides of the top arch are provided with arch foot longitudinal beams;

[0029] The two arch foot longitudinal beams are used to bear the vertical and horizontal forces transmitted by the top arch;

[0030] The structure from the top plate to the top arch, as well as the connection position between each row of columns and the bottom arch, are constructed with separate pilot holes.

[0031] Each of the columns is constructed from the guide hole for constructing the top arch to the position where the column is connected to the bottom arch using manually excavated piles.

[0032] Preferably, the lower surface of the top arch, between each arch foot longitudinal beam and the closest top longitudinal beam, and between every two adjacent top longitudinal beams are provided with an upwardly concave arch structure.

[0033] Preferably, the outer side of each of the arch foot longitudinal beams is provided with multiple arch foot foundation reinforcement measures along the length direction to form a longitudinal elastic foundation beam;

[0034] Each of the arch foot foundation reinforcement measures includes a number of micro steel pipe piles with an angle of 15 to 30 degrees to each other.

[0035] The present invention also provides an underground space dark excavation construction method using an underground space single-arch double-column umbrella-shaped support structure, comprising the following steps:

[0036] Step 1: Construct the initial support structure at the connection position between each row of columns and the bottom arch of the underground space, and open a pilot tunnel;

[0037] Step 2: construct an initial support structure corresponding to the position from the top arch to the top plate, and open the pilot hole for accommodating the top longitudinal beam construction only;

[0038] Step 3: construct a portion of the bottom arch and bottom longitudinal beam of corresponding width in the pilot tunnel corresponding to the position where each row of columns connects to the bottom arch of the underground space;

[0039] In the pilot hole corresponding to the top arch from the top plate in the reverse operation, construct a portion of the top arch and a top longitudinal beam of corresponding size;

[0040] Using manually excavated piles to construct each of the columns, and connecting each of the columns to the corresponding top longitudinal beam and the corresponding bottom longitudinal beam;

[0041] Step 4: excavate the soil, expand the pilot hole corresponding to the top arch from the top arch plate to cover the entire top arch, and re-install the initial support structure;

[0042] Step 5: Build the arch foot longitudinal beams and set up micro steel pipe piles to form the arch foot foundation reinforcement measures;

[0043] Step 6: Cast the top arch completely;

[0044] Step 7: Excavate the soil to expand the pilot hole corresponding to the top arch from the top arch to the top arch until it covers the top arch;

[0045] Step 8: construct the top-down middle plate and the side plates of the underground space above it, and set the initial support structure outside the side plates of the completed part;

[0046] Step 9: Continue excavating the soil downward to the top of the pilot tunnel at the location where each row of columns connects to the bottom arch of the underground space, and set the initial support structure on the outer side of the side plate of the corresponding underground space;

[0047] Step 10: Continue excavating the soil from the middle of the underground space downward to the bottom arch position, and cast the bottom arch between every two rows of columns;

[0048] Step 11: excavating soil along the bottom arch to both sides to the side plate position of the underground space, and setting the initial support structure outside the side plate;

[0049] Step 12: Cast the side panels and bottom arch of the underground space completely, and perform waterproofing and secondary lining construction.

[0050] Preferably, the initial support structure includes anchor rods, small pipes, steel frames or sprayed concrete.

[0051] Preferably, in step 2, a middle partition wall is required to be set in the guide tunnel corresponding to the reverse-worked middle plate to the top arch, and is removed in step 3; before removing the middle partition wall, temporary steel pipe supports are set up before and after the position where the middle partition wall is removed in the underground space.

[0052] Preferably, in step 3, waterproofing construction is performed on the bottom arch.

[0053] Preferably, in step 6, before the complete top arch is cast, temporary steel pipe supports are set up before and after the middle partition wall is removed in the underground space.

[0054] Preferably, after the secondary lining construction is completed, the remaining secondary structure is constructed in the underground space.

[0055] Beneficial effects of the present invention:

[0056] The present invention can solve the difficulty of forming an arch using the single-arch arch-capping method under shallow soil conditions, as well as the problem of unstable intermediate column nodes and water accumulation at V-shaped nodes in the double-arch single-column arch-capping method. It economically, reasonably, safely, and efficiently completes the arrangement of a large-section underground structure support system using the concealed excavation method under shallow soil conditions.

[0057] The present invention inherits the advantages of the arch cover method, such as low construction difficulty, fast construction speed and less process conversion; at the same time, there is no need to set up a separate pilot hole at the arch foot, avoiding the problem of over-excavation and backfilling; it can reduce the construction steps in the arch formation process and improve construction efficiency; it can be applied to larger concealed excavation sections (i.e., larger spans and higher heights); the top arch of the single arch system is not easy to accumulate water, and the waterproof effect is good.

[0058] The present invention innovates from the aspects of overall construction steps, top arch excavation process, overall composition type, arch foot stabilization measures, and column stabilization measures to form a single-arch double-column umbrella-shaped support system.

[0059] Compared with the existing technology, the present invention can more economically, reasonably, safely and efficiently complete the arrangement of a large-section single-arch double-column umbrella-shaped support system using the underground excavation method, and can safely and quickly complete the construction of underground structures.

[0060] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A schematic diagram showing a state of completing step 1 in one embodiment of the present invention is shown.

[0062] Figure 2A schematic diagram showing the state of completing step 2 in one embodiment of the present invention is shown.

[0063] Figure 3 A schematic diagram showing a state of completing step 3 in one embodiment of the present invention is shown.

[0064] Figure 4 A schematic diagram showing a state of completing step 4 in one embodiment of the present invention is shown.

[0065] Figure 5 A schematic diagram showing a state of completing step 5 in one embodiment of the present invention is shown.

[0066] Figure 6 A schematic diagram showing the state of completing step 6 in one embodiment of the present invention is shown.

[0067] Figure 7 A schematic diagram showing the state of completing step 7 in one embodiment of the present invention is shown.

[0068] Figure 8 A schematic diagram showing the state of completing step 8 in one embodiment of the present invention is shown.

[0069] Figure 9 A schematic diagram illustrating the state of the top of the pilot tunnel where soil is excavated downward to the position where each row of columns is connected to the bottom arch in one embodiment of the present invention.

[0070] Figure 10 A schematic diagram showing the state of completing step 9 in one embodiment of the present invention is shown.

[0071] Figure 11 FIG. 1 is a schematic diagram showing a state in which step 10 is completed in one embodiment of the present invention.

[0072] Figure 12 A schematic diagram showing a state of completing step 11 in one embodiment of the present invention is shown.

[0073] Figure 13 FIG. 1 is a schematic diagram showing a state in which step 12 is completed in one embodiment of the present invention.

[0074] Figure 14 A schematic diagram showing the status of the remaining secondary structure after construction is completed in one embodiment of the present invention.

[0075] Figure 15 A schematic structural diagram showing three micro steel pipe piles forming an arch foot foundation reinforcement measure in one embodiment of the present invention. DETAILED DESCRIPTION

[0076] Example 1

[0077] like Figure 8 and Figure 15As shown, the underground space single-arch double-column umbrella-shaped support structure includes a top arch 1 extending along the length direction of the underground space and arching upward in the cross section, at least two top longitudinal beams 11 arranged on the lower surface of the top arch 1, bottom longitudinal beams 71 arranged on the bottom arch 7 of the underground space and corresponding to the top longitudinal beams 11, multiple rows of columns 2 arranged between each top longitudinal beam 11 and the corresponding bottom longitudinal beam 71, and a reverse-worked middle plate 4 arranged between the top arch 1 and the bottom arch 7;

[0078] In actual application, the top arch 1 extending along the length of the underground space and arching upward in the cross section forms a single umbrella-shaped structure, which mainly bears the overlying water and soil pressure load. The upper surface of the top arch 1 is smooth and not easy to accumulate water, and has a good waterproof effect.

[0079] Partial side panels 5 belonging to the underground space are provided between both sides of the reverse working middle plate 4 and both sides of the top arch 1;

[0080] The side panels 5 of the underground space above the reverse-worked middle panel 4 and the upper surface of the top arch 1 are provided with an initial support structure 6;

[0081] Both sides of the top arch 1 are provided with arch foot longitudinal beams 3;

[0082] The two arch foot longitudinal beams 3 are used to bear the vertical and horizontal forces transmitted by the top arch 1;

[0083] The structure from the reverse-worked middle plate 4 to the top arch 1, as well as the connection position of each row of columns 2 and the bottom arch 7, are constructed by separately opening a pilot hole 8;

[0084] Each of the columns 2 is constructed from the top-down middle plate 4 to the guide hole 8 of the top arch 1 using manually excavated piles to the guide hole 8 at the position where the corresponding column 2 is connected to the bottom arch 7.

[0085] In practical applications, the structure from the reverse-worked middle plate 4 to the top arch 1 is constructed in the same pilot tunnel, and the reverse-worked middle plate 4 can be used in advance to reduce the calculated interval length between each two rows of columns 2, thereby improving the stability of the columns 2.

[0086] In order to improve the stability of the column 2, it is necessary to add a horizontal constraint in the middle of the column, and use the reverse plate 4 to increase the horizontal displacement constraint of the column 2, reduce the calculated length of the column 2, and increase the stability of the column 2.

[0087] In some embodiments, an upwardly concave arch structure 12 is provided on the lower surface of the top arch 1 , between each arch foot longitudinal beam 3 and the closest top longitudinal beam 11 , and between every two adjacent top longitudinal beams 11 .

[0088] In some embodiments, the outer side of each of the arch foot longitudinal beams 3 is provided with multiple arch foot foundation reinforcement measures along the length direction to form a longitudinal elastic foundation beam;

[0089] Each of the arch foot foundation reinforcement measures includes a number of micro steel pipe piles 31 that are angled at 15 to 30 degrees relative to each other.

[0090] The present invention adopts the arch foot longitudinal beam as the foundation of the umbrella support system, bearing the horizontal and vertical loads of the arch foot of the umbrella support system, and adopts micro steel pipe piles 31 as the arch foot foundation reinforcement measure. The longitudinal spacing of the arch foot foundation reinforcement measure can be arranged according to calculation requirements, so that the arch foot longitudinal beam 3 forms a longitudinal elastic foundation beam under the support of the micro steel pipe piles 31.

[0091] like Figures 1 to 13 As shown, the present invention also provides an underground space dark excavation construction method using an underground space single-arch double-column umbrella-shaped support structure, comprising the following steps:

[0092] like Figure 1 As shown, step 1, construct an initial support structure 6 at the location where each row of columns 2 connects to the bottom arch 7 of the underground space, and open a pilot tunnel 8;

[0093] like Figure 2 As shown, in step 2, the initial support structure 6 is constructed from the top plate 4 to the top arch 1, and the pilot hole 8 is opened to accommodate the construction of the top longitudinal beam 11.

[0094] like Figure 3 As shown, in step 3, in the pilot tunnel 8 corresponding to the position where each row of columns 2 connects with the bottom arch 7 of the underground space, a portion of the bottom arch 7 and a bottom longitudinal beam 71 of corresponding width are constructed;

[0095] In the pilot hole 8 corresponding to the top arch 1 from the top plate 4 in the reverse operation, a portion of the top arch 1 and a top longitudinal beam 11 of a corresponding size are constructed;

[0096] Each of the columns 2 is constructed using manually bored piles, and each of the columns 2 is connected to the corresponding top longitudinal beam 11 and the corresponding bottom longitudinal beam 71;

[0097] like Figure 4 As shown, step 4 is to excavate the soil, expand the pilot hole 8 corresponding to the top arch 1 from the top arch 1 to cover the entire top arch 1, and re-install the initial support structure 6;

[0098] like Figure 5 As shown, step 5, construct the arch foot longitudinal beam 3, and set the micro steel pipe pile 31 to form the arch foot foundation reinforcement measure;

[0099] like Figure 6As shown, step 6, the top arch 1 is cast completely;

[0100] like Figure 7 As shown, step 7, excavating the soil to expand the pilot hole 8 corresponding to the reverse-worked middle plate 4 to the top arch 1 to cover the reverse-worked middle plate 4;

[0101] like Figure 8 As shown, step 8, constructing the top-down middle plate 4 and the side plates 5 of the underground space above it, and setting the initial support structure 6 on the outside of the side plates 5 of the completed part;

[0102] like Figure 9 and Figure 10 As shown, step 9, continue to excavate the soil downward to the top of the pilot hole 8 where each row of the columns 2 is connected to the bottom arch 7 of the underground space, and set the initial support structure 6 on the outer side of the side plate 5 of the corresponding underground space;

[0103] like Figure 11 As shown, step 10, continue to excavate the soil from the middle of the underground space downward to the position of the bottom arch 7, and cast the bottom arch 7 between every two rows of columns 2 completely;

[0104] like Figure 12 As shown, in step 11, soil is excavated along the bottom arch 7 to both sides to the position of the side plate 5 of the underground space, and the initial support structure 6 is set outside the side plate 5;

[0105] like Figure 13 As shown, in step 12, the side panels and the bottom arch 7 of the underground space are cast completely, and waterproofing and secondary lining construction are performed.

[0106] In practical application, the underground space is an underground rail transit station.

[0107] In some embodiments, the primary support structure 6 includes anchor rods, small pipes, steel frames or sprayed concrete.

[0108] In some embodiments, in step 2, a middle partition wall 81 is required to be set in the guide hole 8 corresponding to the reverse-worked middle plate 4 to the top arch 1, and is removed in step 3; before removing the middle partition wall 81, temporary steel pipe supports 82 are set up before and after the position where the middle partition wall 81 is removed in the underground space.

[0109] In some embodiments, in step 3, waterproofing construction is performed on the bottom arch 7.

[0110] In some embodiments, in step 6, before the complete top arch 1 is cast, temporary steel pipe supports 82 are set up before and after the position where the middle partition wall 81 is removed in the underground space.

[0111] like Figure 14 As shown, in some embodiments, after the secondary lining construction is completed, the remaining secondary structure 9 is constructed in the underground space.

[0112] Example 2

[0113] For example, a subway station is located beneath an existing main road in a busy urban area. Numerous municipal pipelines are laid along the road, and there are several high-rise buildings nearby. To avoid disrupting surface traffic and the municipal pipelines, a covered excavation method was required.

[0114] The excavation span of the station is 25m, the excavation height is 19m, and the cover thickness is 12m. The main body of the station is located in the medium-weathered rock layer, and the area above the station is mainly red clay, which belongs to the "soft upper layer and hard lower layer" layer.

[0115] In order to solve the difficulty of arch construction in the arch covering method without intermediate columns under shallow overburden conditions, as well as the waterproofing problem of the "V"-shaped node of the double-arch and single-column arch covering method, underground excavation construction was carried out under the support of the umbrella-shaped top arch and double columns. The specific method is as follows:

[0116] First, excavate the lower pilot tunnel, then the upper pilot tunnel. See the attached Figure 1 , Attachment Figure 2 ,, construct the top longitudinal beam in the upper pilot hole, and the bottom longitudinal beam in the lower pilot hole, see the attached Figure 3 ; The top and bottom longitudinal beams are the key nodes of the umbrella support system.

[0117] Secondly, the middle double columns are constructed by manual hole digging method, and the middle part of the top arch is cast at the same time; the middle double column support system is formed. Figure 3 The manual excavation method is suitable for pile foundation and column operations under low clearance conditions.

[0118] Next, excavate the upper left and right pilot tunnels simultaneously. Figure 4 , construct the top arch concrete and arch foot longitudinal beams on both sides, and set the arch foot longitudinal beams with locking anchor rods, see the attached Figure 5 After removing the temporary middle support, connect the top arch as a whole to form the first top arch-middle double column umbrella-shaped basic support system; after the groove is excavated downward to below the bottom surface of the middle plate, attach Figure 7 , cast the middle plate and side wall, and connect them with the arch foot to form a whole, as shown in the attached Figure 8 As shown, a complete top arch-middle double column umbrella-shaped support system is formed.

[0119] The top arch, center double-column umbrella support system is the core and foundation of this construction method. Its unique feature is that it fully utilizes a single large top arch to bear the load of the soft soil above, transferring this load to the arch feet and center columns on both sides, and then to the underlying rock strata. This system is particularly suitable for shallow overburden (soft on top, hard on the bottom) strata. Subsequent excavation can be carried out under this system, improving efficiency and reducing construction time.

[0120] Finally, under this top arch-intermediate double column support system, continue to excavate the remaining soil layer by layer. Figure 9 To the attached Figure 14 , complete the pouring of the remaining internal secondary structure.

[0121] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. Underground space single arch double column umbrella support structure; characterized by: It comprises a top arch (1) extending along the length direction of the underground space and arching upward in cross section, at least two top longitudinal beams (11) arranged on the lower surface of the top arch (1), bottom longitudinal beams (71) arranged on the bottom arch (7) of the underground space and corresponding to the top longitudinal beams (11), multiple rows of columns (2) arranged between each top longitudinal beam (11) and the corresponding bottom longitudinal beam (71), and a reverse-worked middle plate (4) arranged between the top arch (1) and the bottom arch (7); Partial side panels (5) belonging to the underground space are provided between both sides of the reverse working middle plate (4) and both sides of the top arch (1); The side panels (5) of the underground space above the reverse working middle panel (4) and the upper surface of the top arch (1) are both provided with an initial support structure (6); Both sides of the top arch (1) are provided with arch foot longitudinal beams (3); The two arch foot longitudinal beams (3) are used to bear the vertical and horizontal forces transmitted by the top arch (1); The structure from the reverse-worked middle plate (4) to the top arch (1), as well as the connection position between each row of the columns (2) and the bottom arch (7), are all constructed with separate guide holes (8); Each of the columns (2) is constructed from the reverse-worked middle plate (4) to the guide hole (8) of the top arch (1) using manually excavated piles to the guide hole (8) at the position where the corresponding column (2) is connected to the bottom arch (7).

2. The underground space single-arch double-column umbrella-shaped support structure according to claim 1, characterized in that: The lower surface of the top arch (1), between each arch foot longitudinal beam (3) and the closest top longitudinal beam (11), and between each two adjacent top longitudinal beams (11) are provided with an upwardly concave arch structure (12).

3. The underground space single-arch double-column umbrella-shaped support structure according to claim 1, characterized in that: The outer side of each of the arch foot longitudinal beams (3) is provided with a plurality of arch foot foundation reinforcement measures along the length direction to form a longitudinal elastic foundation beam; Each of the arch foot foundation reinforcement measures includes a plurality of micro steel pipe piles (31) that are at an angle of 15 to 30 degrees to each other.

4. An underground space dark excavation construction method using an underground space single arch double column umbrella support structure is characterized in that: The steps include: Step 1: construct an initial support structure (6) at the connection position between each row of columns (2) and the bottom arch (7) of the underground space, and open a pilot tunnel (8); Step 2: constructing an initial support structure (6) corresponding to the position of the reverse-constructed middle plate (4) to the top arch (1), and opening the pilot hole (8) that only accommodates the construction of the top longitudinal beam (11); Step 3: constructing a portion of the bottom arch (7) and a bottom longitudinal beam (71) of a corresponding width in the pilot tunnel (8) corresponding to the connection position between each row of columns (2) and the bottom arch (7) of the underground space; In the pilot hole (8) corresponding to the top arch (1) from the top plate (4) in the reverse operation, a portion of the top arch (1) and a top longitudinal beam (11) of a corresponding size are constructed; Each of the columns (2) is constructed using manually bored piles, and each of the columns (2) is connected to the corresponding top longitudinal beam (11) and the corresponding bottom longitudinal beam (71); Step 4: excavate the soil, expand the pilot hole (8) corresponding to the top arch (1) from the top arch (4) to cover the entire top arch (1), and re-install the initial support structure (6); Step 5: construct the arch foot longitudinal beam (3) and set up micro steel pipe piles (31) to form the arch foot foundation reinforcement measures; Step 6: Cast the top arch (1) completely; Step 7: Excavate the soil to expand the pilot hole (8) corresponding to the reverse middle plate (4) to the top arch (1) to cover the reverse middle plate (4); Step 8: construct the top-down middle plate (4) and the side plates (5) of the underground space above it, and set the initial support structure (6) outside the side plates (5) of the completed part; Step 9, continue to excavate the soil downward to the top of the guide tunnel (8) at the position where each row of the columns (2) is connected to the bottom arch (7) of the underground space, and set the initial support structure (6) on the outside of the side plate (5) of the corresponding underground space; Step 10: Continue excavating the soil from the middle of the underground space downward to the position of the bottom arch (7), and cast the bottom arch (7) between every two rows of columns (2); Step 11: excavating soil along the bottom arch (7) to both sides to the position of the side panels (5) of the underground space, and setting the initial support structure (6) outside the side panels (5); Step 12: Cast the side panels and the bottom arch (7) of the underground space completely, and perform waterproofing and secondary lining construction.

5. The underground space dark excavation construction method using the underground space single arch double column umbrella support structure according to claim 4 is characterized in that: The initial support structure (6) includes anchor rods, small pipes, steel frames or sprayed concrete.

6. The underground space dark excavation construction method using the underground space single arch double column umbrella support structure according to claim 4 is characterized in that: In step 2, a middle partition wall (81) is required to be set in the guide hole (8) corresponding to the reverse-worked middle plate (4) to the top arch (1), and is removed in step 3; before removing the middle partition wall (81), temporary steel pipe supports (82) are set up before and after the position where the middle partition wall (81) is removed in the underground space.

7. The underground space dark excavation construction method using the underground space single arch double column umbrella support structure according to claim 4 is characterized in that: In step 3, waterproofing construction is performed on the bottom arch (7).

8. The underground space dark excavation construction method using the underground space single arch double column umbrella support structure according to claim 4 is characterized in that: In step 6, before pouring the complete top arch (1), temporary steel pipe supports (82) are set up before and after the position where the middle partition wall (81) is removed in the underground space.

9. The underground space dark excavation construction method using the underground space single arch double column umbrella support structure according to claim 4 is characterized in that: After the secondary lining construction is completed, the remaining secondary structure (9) is constructed in the underground space.

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