Underground excavation supporting structure capable of freely expanding boundary for large-span underground cavern and construction method

Abstract

The invention discloses an underground excavation supporting structure capable of freely expanding boundaries for a large-span underground cavern and a construction method, the overall design thought of the supporting structure is that a structural unit is formed by structural members such as a middle pile / column, each layer of beam, a large arch and each layer of structural plate, and the structural members are arranged in a set cavern boundary range. The underground cavern is formed by freely expanding a plurality of structural units in the transverse dimension, the longitudinal dimension and the vertical dimension. According to underground cavern scale requirements in different periods, boundaries can be expanded at any time, structural units can be increased, and the cavern scale can be expanded. The span of a single structural unit can be flexibly designed. During implementation of the supporting structure, temporary projects such as a working well, a main construction tunnel and auxiliary construction tunnels are arranged, the working well is arranged above the main construction tunnel or at one end of the side face of the main construction tunnel according to conditions such as site conditions and work planning organizations, and the auxiliary construction tunnels can be arranged on the single side or the two sides of the main construction tunnel. The temporary project can be combined with an auxiliary project to achieve permanent and temporary combination.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground cavern support, and in particular relates to a dark excavation support structure and a construction method for a large-span underground cavern with freely expandable boundaries. Background Art

[0002] With the continuous deepening of domestic infrastructure construction, tunnels and underground projects have become indispensable facilities for human production and life. Driven by the gradual improvement of human use of tunnels and underground projects, the cross-section has gradually increased, and large-span traffic tunnels, underground storage tanks, civil air defense projects, underground service facilities, etc. have increased rapidly. Although my country has a large number of large-span underground projects under construction, there is still a large gap in the design and construction of large-span underground caverns compared with international advanced technologies, which directly affects the improvement of project benefits and restricts the overall improvement of my country's international competitiveness. At present, the main construction methods of domestic underground projects include half-section method, step method, double-side wall pilot pit method, single rock column support partial excavation method, subway station hole pile method, etc. The above methods are mainly suitable for narrow and long underground projects with a cross-section span of generally less than 20m, and are not suitable for large-volume and large-span underground projects. Although the cross-section size of the hole pile method used in the subway field is relatively large, it is still a narrow and long space as a whole, with a cross-section width of generally less than 22m and a column span of less than 10m, which is also not suitable for large-volume underground projects. For this reason, underground engineering practitioners urgently need to research and develop support structures and construction methods suitable for large-volume and large-span underground caverns. Summary of the invention

[0003] In response to the above-mentioned technical problems, the present invention provides a dark-cut support structure and construction method for large-span underground caverns with freely expandable boundaries, enriching the underground engineering support structure system and construction methods, and solving the construction difficulties of large-volume underground caverns / caverns.

[0004] The present invention achieves this purpose through the following technical solutions:

[0005] On the one hand, the present invention provides a dark excavation support structure for a large-span underground cavern with freely expandable boundaries, comprising a plurality of structural units arranged continuously in the horizontal and vertical directions inside and an outermost side wall and side piles, the structural unit comprising a pile foundation, a bottom plate, a bottom beam, a structural plate, a layer beam, a structural beam, a large arch and a middle pile / column, the middle pile / column is arranged on the pile foundation, the top of the middle pile / column supports the structural beam, the large arch is arranged between adjacent structural beams, the arch foot is connected to the structural beam, a bottom beam is cast between adjacent middle piles / columns supporting the same structural beam, a bottom plate is cast between the bottom beams, the bottom plate is located on the top of the pile foundation, a plurality of layer beams are cast between adjacent middle piles / columns and the structural beam, and a structural plate is cast between the layer beams at the same horizontal height, a side pile is arranged on the outermost side of the support structure, a crown beam is arranged on the top of the side pile parallel to the structural beam, which is used to support the outer arch foot of the large arch of the structural unit located on the outside, a side wall is arranged on the inner side of the side pile, each layer of structural plate is connected to the side wall on the outer side of the bottom plate, and the top of the side wall is connected to the large arch.

[0006] Another aspect of the present invention provides a construction method for a dark excavation support structure with a freely expandable boundary for a large-span underground cavern, comprising the following steps:

[0007] Step 1: Determine the number and location of working wells based on ground environmental conditions, engineering geology, ancillary facilities, engineering organization, and project scale, and dig working wells;

[0008] Step 2: excavate the main construction tunnel from the working pit, and then excavate the auxiliary construction tunnel perpendicular to the main construction tunnel in the main construction tunnel;

[0009] Step 3: Use pile-driving equipment to construct pile foundations, middle piles / columns and side piles in the auxiliary construction tunnel according to the positions on the drawings, and then construct the structural beams and the crown beams on top of the side piles;

[0010] Step 4: Dig out the construction space of the big arch, construct the big arch between the adjacent structural beams, connect the arch foot with the structural beam, and set the arch foot on the outermost side on the crown beam at the top of the side pile, thus forming the main force bearing system of big arch - structural beam - middle pile / column - pile foundation;

[0011] Step 5: Carry out mechanized earth excavation, excavate to each layer of structural slabs and cast the layer beams, structural slabs and the outermost side walls;

[0012] Step 6: When excavating to the lowest level, cast the bottom beam, bottom plate and outermost side wall.

[0013] Furthermore, depending on site conditions, the working pit may be arranged above one end or the middle of the main construction tunnel.

[0014] Furthermore, the auxiliary construction tunnel is arranged on one side of the main construction tunnel, or on both sides of the main construction tunnel.

[0015] Furthermore, the main arch body is constructed from top to bottom through the main construction tunnel and the auxiliary construction tunnel, and can be constructed sequentially or at intervals according to the needs of the project organization.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention creatively proposes a large-span underground cavern support structure. A single structural unit can be repeatedly combined to form an integral underground cavern / cavern. It can be freely expanded in the horizontal, longitudinal and vertical dimensions. It is suitable for underground cavern projects of various sizes, especially large arch spans, which are suitable for large-span underground caverns / caverns. Main projects such as piles and earthwork can be mechanized, which greatly improves construction efficiency, shortens construction period, and reduces project investment. Working wells, main construction tunnels, etc. can be set up in combination with ancillary facilities to achieve a combination of permanent and temporary facilities, reduce the amount of work, and reduce the project cost. The support structure and construction method are suitable for both soil strata and rock strata.

[0018] The present invention proposes a concealed excavation support structure and construction method with freely expandable boundaries for large-span underground caverns. As a new set of underground engineering structural forms, it has promoted the development of underground engineering mechanization, solved the construction problems of large-volume underground caverns / caverns, enriched the support structure forms and construction methods of underground engineering, and taken a solid step towards the development of large-span underground cavern construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0020] Figure 1 It is a cross-sectional view of the large-span underground cavern support structure of the present invention;

[0021] Figure 2 It is a schematic diagram of the planar arrangement of the working well of the present invention;

[0022] Figure 3 It is a schematic diagram of the specific structure of an embodiment of the present invention;

[0023] Figure 4 This is a construction process diagram of an embodiment of the present invention.

[0024] Reference numerals in the figure: 1-pile foundation, 2-middle pile / column, 3-structural beam, 4-large arch, 5-layer beam, 6-bottom beam, 7-structural plate, 8-bottom plate, 9-side wall, 10-side pile, 11-working shaft, 12-main construction tunnel, 13-auxiliary construction tunnel, 14-crown beam. DETAILED DESCRIPTION

[0025] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0026] See also Figure 1 , Figure 3 The present invention discloses a dark excavation support structure for a large-span underground cavern with a freely expandable boundary, comprising a plurality of structural units arranged inside in a continuous manner in the horizontal and vertical directions and an outermost side wall 9 and a side pile 10, wherein the structural unit comprises a pile foundation 1, a bottom plate 8, a bottom beam 5, a structural plate 7, a layer beam 5, a structural beam 3, a large arch 4 and a middle pile / column 2, wherein the middle pile / column 2 is arranged on the pile foundation 1, the top of the middle pile / column 2 supports the structural beam 3, the large arch 4 is erected between adjacent structural beams 3, the arch foot is connected to the structural beam 3, and the adjacent middle piles / columns supporting the same structural beam 3 are connected to the arch foot. Bottom beams 5 are cast between the columns 2, bottom plates 8 are cast between the bottom beams 5, and the bottom plate 8 is located on the top of the pile foundation 1. Several layers of beams 5 are cast between the bottom beams 6 and the structural beams 3 of the adjacent middle piles / columns 2, and structural plates 7 are cast between the layer beams 5 at the same horizontal height. Side piles 10 are provided on the outermost side of the supporting structure, and crown beams 14 are provided on the top of the side piles 10 parallel to the structural beams 3 to support the outer arch feet of the structural unit large arch 4 located on the outside. Side walls 9 are provided on the inner side of the side piles 10, and each layer of structural plates 7 is connected to the side wall 9 on the outer side of the bottom plate 5, and the top of the side wall 9 is connected to the large arch 4.

[0027] The internal structural units in the support structure are designed according to the specific needs, the number of layers and the span of the arch 4, and then extend outward in the horizontal and vertical directions according to the set structural units, and are connected to the side piles 10 and the side wall 9 at the outermost boundary. Structural units with different spans can also be designed and combined, but the structural units connected along the depth direction of the arch 4 must maintain the same span, and the structural units connected in the transverse direction can adopt different spans, that is, different span designs can be adopted between the longitudinal structural beams 3 of the overall structure.

[0028] During the implementation of the support structure, temporary projects such as the working shaft 11, the main construction tunnel 12, and the auxiliary construction tunnel 13 are set up.

[0029] The following is Figure 3 The construction process of the large-span underground cavern support structure shown in the figure is further explained. Figure 4 shown.

[0030] Step 1: Determine the number and location of working wells 11 based on comprehensive ground environmental conditions, engineering geology, ancillary facilities, engineering organization, and project scale factors, and excavate working wells 11;

[0031] Step 2: excavating a main construction tunnel 12 from the working shaft 11, and then excavating an auxiliary construction tunnel 13 perpendicular to the main construction tunnel 12 in the main construction tunnel 12;

[0032] Step 3: Use pile-making equipment to construct pile foundation 1, middle pile / column 2 and side pile 10 in the auxiliary construction tunnel 13 according to the position in the drawing, and after completion, construct structural beam 3 and cap beam 14 on the top of side pile 10 parallel to structural beam 3;

[0033] Step 4: excavate the construction space of the large arch 4, construct the large arch 4 between the adjacent structural beams 3, the arch foot of the large arch 4 is connected to the structural beam 3, and the arch foot of the large arch 4 located on the outermost side is arranged on the top crown beam 14 of the side pile 10, forming the main force bearing system of the large arch - structural beam - middle pile / column - pile foundation;

[0034] Step 5: Carry out mechanized earthwork excavation, excavate to each layer of structural plate 7 to cast the layer beam 5, structural plate 7 and the outermost side wall 9; the construction of each layer of side wall 9 needs to reserve the reinforcement connection conditions of the next layer of side wall 9;

[0035] Step 6: When excavating to the lowest layer, cast the bottom beam 6, bottom plate 8 and the outermost side wall 9, and then backfill the working shaft and the main construction tunnel 12, or construct a secondary lining structure for the permanent and temporary working shaft 11 and the main construction tunnel 12.

[0036] For completed projects that need to be expanded, it is necessary to construct pile foundation 1, middle pile / column 2 and structural beam 3 while demolishing side wall 9, side pile 10 and crown beam 14, and then expand the project scale according to steps one to six.

[0037] like Figure 2 As shown, the working shaft 11 is the main vertical passage for material transportation, personnel entry and exit, and tunnel ventilation during the construction of the underground cavern. According to the site conditions, it can be set above any position in the middle of the main construction tunnel 12 or at one end of the main construction tunnel 12, and can also be combined with the ground ancillary projects of the underground cavern to achieve permanent and temporary integration.

[0038] The auxiliary construction tunnel 13 may be arranged on one side of the main construction tunnel 12 or on both sides.

[0039] The main construction tunnel 12 and the auxiliary construction tunnel 13 are used to construct the main body of the arch 4 from top to bottom. The construction can be carried out sequentially or at intervals according to the needs of the project organization. The span can be flexibly designed according to functional requirements in combination with auxiliary measures such as anchor rods and pipe sheds. The span can be equal or unequal, which is determined by calculation.

[0040] The rock and soil excavation at the structural unit location is performed by setting side piles 10 as retaining structures only at the boundary positions, and the other non-boundary units are excavated step by step and layer by layer under the protection of the large arch 4.

[0041] The present invention has been described in detail above through embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. Anyone who utilizes the technical solution described in the present invention, or a technician in the field, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and protection scope of the present invention to achieve the above technical effects, or makes equal changes and improvements to the scope of application, shall still belong to the scope of protection covered by the patent of the present invention. It should be noted that in order to make a clear statement, the description of some components and processes that have no direct and obvious connection with the scope of protection of the present invention but are known to those skilled in the art are omitted in the description of the present invention.

Claims

1. A dark excavation support structure for a large-span underground cavern with freely expandable boundaries, characterized in that: It includes a plurality of structural units arranged continuously in the horizontal and vertical directions inside and the outermost side walls and side piles. The structural units include pile foundations, bottom plates, bottom beams, structural plates, layer beams, structural beams, large arches and middle piles / columns. The middle piles / columns are arranged on the pile foundations. The tops of the middle piles / columns support the structural beams. The large arches are arranged between adjacent structural beams. The arch feet are connected to the structural beams. Bottom beams are cast between adjacent middle piles / columns supporting the same structural beam. Bottom plates are cast between the bottom beams. The bottom plates are located on the top of the pile foundations. Several layer beams are cast between the bottom beams and the structural beams between adjacent middle piles / columns. Structural plates are cast between the layer beams at the same horizontal height. Side piles are arranged on the outermost side of the supporting structure. A crown beam is arranged on the top of the side piles parallel to the structural beams to support the outer arch feet of the large arches of the structural units located on the outside. Side walls are arranged on the inner sides of the side piles. The structural plates of each layer are connected to the side walls on the outer side of the bottom plate. The tops of the side walls are connected to the large arches.

2. A construction method for a dark excavation support structure with freely expandable boundaries for a large-span underground cavern according to claim 1, characterized in that: The steps include: Step 1: Determine the number and location of working wells based on ground environmental conditions, engineering geology, ancillary facilities, engineering organization, and project scale, and dig working wells; Step 2: excavate the main construction tunnel from the working pit, and then excavate the auxiliary construction tunnel perpendicular to the main construction tunnel in the main construction tunnel; Step 3: Use pile-driving equipment to construct pile foundation, middle pile / column and side piles in the auxiliary construction tunnel according to the positions on the drawings, and then construct the structural beam and the cap beam on the top of the side pile parallel to the structural beam; Step 4: Dig out the construction space of the big arch, construct the big arch between the adjacent structural beams, connect the arch foot with the structural beam, and set the arch foot on the outermost side on the crown beam at the top of the side pile, thus forming the main force bearing system of big arch - structural beam - middle pile / column - pile foundation; Step 5: Carry out mechanized earth excavation, excavate to each layer of structural slabs and cast the layer beams, structural slabs and the outermost side walls; Step 6: When excavating to the lowest level, cast the bottom beam, bottom plate and outermost side wall.

3. The construction method of a dark excavation support structure for a large-span underground cavern with freely expandable boundaries according to claim 2 is characterized in that: Depending on site conditions, the working pit can be set up at one end or above the middle of the main construction tunnel.

4. The construction method of a dark excavation support structure for a large-span underground cavern with freely expandable boundaries according to claim 2 is characterized in that: The auxiliary construction tunnel is arranged on one side of the main construction tunnel, or on both sides of the main construction tunnel.

5. The construction method of a dark excavation support structure for a large-span underground cavern with freely expandable boundaries according to claim 2, characterized in that: The main arch body is constructed from top to bottom through the main construction tunnel and the auxiliary construction tunnel. The construction can be carried out sequentially or at intervals according to the needs of the project organization.

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