CN221399099U - Assembled integral underground structure - Google Patents

Abstract

The utility model discloses an assembled integral underground structure, which comprises a cast-in-situ bottom plate structure, a prefabricated middle plate structure and a top plate structure, wherein the lower part of the cast-in-situ bottom plate structure, the middle part of the prefabricated middle plate structure and the top plate structure are arranged between the cast-in-situ bottom plate structure, the prefabricated middle plate structure and the top plate structure respectively; the prefabricated assembly and partial cast-in-situ forming assembly integral underground structure realizes integral assembly, does not need to simply pursue assembly rate, does not need to set up templates and supports on site, and is additionally provided with the waterproof layer on the outer side of the top plate and the bottom plate, so that the prefabricated part has controllable quality, good structural integrity of a finished product, strong integral rigidity and good waterproof effect, and the construction efficiency is improved, the construction quality is improved, the construction period is further shortened, and the cost is reduced.

Description

Assembled integral underground structure

Technical Field

The utility model belongs to the technical field of underground structure engineering, and particularly relates to an assembled integral underground structure.

Background

At present, china is strongly pushing a prefabricated assembly structure, wherein the prefabricated assembly structure is a concrete structure which is formed by taking prefabricated components as main components, assembling, connecting and partially casting in situ. The method has the advantages of mass production, uniform quality, short construction period, high construction precision, low construction cost and the like.

At present, part of cities adopt a composite structure of underground engineering constructed by a surface (cover) excavation method, and the internal underground structure adopts a fully assembled structure, so that the assembly rate is improved, but the rigidity of the whole structure is weak relative to that of a cast-in-situ structure.

Disclosure of Invention

The utility model provides an assembled integral underground structure and a construction method thereof, which aim to solve the problems existing in the prior art.

The technical scheme of the utility model is as follows: the utility model provides an assembled integral underground structure, includes prefabricated side wall, be provided with the cast-in-place bottom plate structure that is located the lower part between the prefabricated side wall, be provided with the prefabricated medium plate structure that is located the middle part between the prefabricated side wall, be provided with the prefabricated roof structure that is located the top and cast-in-place coincide together between the prefabricated side wall, be provided with vertical support's lower floor's structure post between cast-in-place bottom plate structure and the prefabricated medium plate structure, be provided with vertical support's superstructure post between prefabricated medium plate structure and the roof structure, lower floor's structure post top is equipped with the well longeron of prefabrication and coincide well longeron formation an organic whole, superstructure post top is equipped with prefabricated roof longeron and coincide roof longeron formation an organic whole.

Further, the cast-in-situ bottom plate structure comprises a cast-in-situ bottom plate and a cast-in-situ bottom longitudinal beam, and the bottom longitudinal beam is positioned in the middle of the bottom plate.

Furthermore, the upper end of the lower layer structure column is provided with a prefabricated middle longitudinal beam, and the prefabricated middle longitudinal beam and the prefabricated side wall provide supporting conditions for the prefabricated middle plate structure.

Still further, prefabricated medium plate structure includes prefabricated medium plate, prefabricated medium plate is set up on the bracket of longeron and prefabricated side wall in prefabricating.

Still further, be provided with the coincide in the longeron in the prefabrication, be provided with the superstructure post in the coincide on the longeron, superstructure post upper end is provided with prefabricated roof longeron, prefabricated roof longeron and prefabricated side wall provide the support condition for roof structure.

Still further, roof structure includes prefabricated roof, prefabricated roof is set up on the bracket at prefabricated roof longeron, prefabricated side wall top.

Furthermore, a cast-in-situ roof laminated layer is arranged at the upper end of the prefabricated roof, a concrete anti-cracking layer is arranged at the upper part of the roof structure, and a waterproof layer and a waterproof protective layer are sequentially arranged at the upper part of the concrete anti-cracking layer.

The beneficial effects of the utility model are as follows:

The prefabricated assembly and partial cast-in-situ forming assembly integral underground structure realizes integral assembly, does not need to simply pursue assembly rate, does not need to set up templates and supports on site, and is additionally provided with the waterproof layer on the outer side of the top plate and the bottom plate, so that the prefabricated part has controllable quality, good structural integrity of a finished product, strong integral rigidity and good waterproof effect, and the construction efficiency is improved, the construction quality is improved, the construction period is further shortened, and the cost is reduced.

Drawings

FIG. 1 is a schematic cross-sectional view of a subterranean structure of the present utility model;

FIG. 2 is a schematic view of the longitudinal assembly of a subterranean structure of the present utility model;

FIG. 3 is a schematic view of an assembled lateral block of an underground structure of the present utility model;

FIG. 4 is a schematic diagram of a construction method step A according to the present utility model;

FIG. 5 is a schematic diagram of a construction method step B of the present utility model;

FIG. 6 is a schematic diagram of a construction method step C of the present utility model;

FIG. 7 is a schematic diagram of a construction method step D in the present utility model;

FIG. 8 is a schematic diagram of a construction method step E in the present utility model;

FIG. 9 is a schematic diagram of a construction method step F in the present utility model;

FIG. 10 is a schematic diagram of a construction method step G according to the present utility model;

FIG. 11 is a schematic diagram of a construction method step H in the present utility model;

FIG. 12 is a schematic illustration of step I of the construction method of the present utility model;

FIG. 13 is a schematic view of a construction method step J of the present utility model;

FIG. 14 is a schematic view of the construction method step K of the present utility model;

wherein:

1. Building enclosure 2 bottom plate

3. Side wall prefabricated longitudinal beam 4 (A block)

5. Lower layer structure column (D block) 6 prefabricated middle longitudinal beam (E block)

7. Finish rolling deformed steel bar 8 prefabrication middle plate (C block)

9. Superimposed middle longitudinal beam 10 superstructure column (F block)

11. Circumferential bolt 12 prefabricated roof (B block)

13. Top plate laminated layer 14 concrete crack resistant layer

15. Waterproof layer 16 waterproof protective layer

17. Prefabricated roof rail (J block) 18 superimposed roof rail

19. 20 Column top retaining wall of main rib of structural column

21. Bracket 22 steel bar connector

23. 24 Column caps of end retaining wall

25. Steel pipe support with tie bar 26

27. And (5) steel support replacement.

Detailed Description

The present utility model will be described in detail below with reference to the drawings and examples:

As shown in fig. 1 to 14, an assembled integral underground structure comprises prefabricated side walls 4, a cast-in-situ bottom plate structure positioned at the lower part is arranged between the prefabricated side walls 4, a prefabricated middle plate structure positioned at the middle part is arranged between the prefabricated side walls 4, a top plate structure positioned at the top is arranged between the prefabricated side walls 4 and is overlapped together in a cast-in-situ manner, a vertically supported lower structure column 5 is arranged between the cast-in-situ bottom plate structure and the prefabricated middle plate structure, and a vertically supported upper structure column 10 is arranged between the prefabricated middle plate structure and the top plate structure.

The cast-in-situ bottom plate structure comprises a cast-in-situ bottom plate 2 and a cast-in-situ bottom longitudinal beam 3, wherein the bottom longitudinal beam 3 is positioned in the middle of the bottom plate 2.

The upper end of the lower layer structure column 5 is provided with a prefabricated middle longitudinal beam 6, and the prefabricated middle longitudinal beam 6 and the prefabricated side wall 4 provide supporting conditions for the prefabricated middle plate structure.

The prefabricated middle plate structure comprises a prefabricated middle plate 8, and the prefabricated middle plate 8 is erected on brackets 21 of the prefabricated middle longitudinal beam 6 and the prefabricated side wall 4.

The prefabricated middle longitudinal beam 6 is provided with a superposed middle longitudinal beam 9, the superposed middle longitudinal beam 9 is provided with an upper layer structure column 10, the upper end of the upper layer structure column 10 is provided with a prefabricated top longitudinal beam 17, and the prefabricated top longitudinal beam 17 and the prefabricated side wall 4 provide supporting conditions for a top plate structure.

The top plate structure comprises a prefabricated top plate 12, and the prefabricated top plate 12 is erected on bracket 21 at the tops of prefabricated top longitudinal beams 17 and prefabricated side walls 4.

The upper end of the prefabricated top plate 12 is provided with a cast-in-situ top plate laminated layer 13, a concrete anti-cracking layer 14 is arranged on the upper portion of the top plate structure, and a waterproof layer 15 and a waterproof protective layer 16 are sequentially arranged on the upper portion of the concrete anti-cracking layer 14.

Specifically, the upper end of the prefabricated top longitudinal beam 17 is provided with a cast-in-situ laminated top longitudinal beam 18.

Specifically, concrete anti-cracking layers 14 are paved at the upper ends of the roof laminated layer 13 and the laminated roof longitudinal beams 18, and waterproof layers 15 and waterproof protective layers 16 are arranged on the concrete anti-cracking layers 14.

Specifically, the lower layer structure post 5 is the D piece, and the lower extreme is provided with structure post main muscle 19, reserve the grout jack in the bottom longitudinal beam 3, the grout jack is put in order with structure post main muscle 19 from top to bottom, realizes linking to each other with the bottom longitudinal beam 3 through structure post main muscle 19.

Specifically, the upper end of the lower layer structure column 5 is provided with a column cap 24, column top retaining walls 20 are arranged on the column cap 24 along the two longitudinal sides, and grouting jacks are reserved on the upper portion of the lower layer structure column 5.

Specifically, prefabricated medium plate 8 is C piece, including being located the C1 piece on the post top barricade 20 of lower floor's structure post 5 and being located the C2 piece on the longeron 6 bracket 21 in prefabricating, the reinforcing bar connector 22 has been pre-buried in opposite side in C1 piece, the C2 piece, reinforcing bar connector 22 is used for reinforcing bar mechanical connection.

Specifically, the opposite sides of the C1 block are further provided with end retaining walls 23 for connection.

Specifically, the upper layer structure post 10 is an F block, the lower extreme is provided with structure post main muscle 19, in the grouting jack that structure post main muscle 19 inserted lower floor structure post 5 upper portion reserved, realize through structure post main muscle 19 that connect into an organic wholely with the beam column node of lower floor structure post 5 and prefabricated well longeron 6 and coincide well longeron 9.

Specifically, the upper end of the superstructure column 10 is provided with a cap 24, the caps 24 are provided with column top retaining walls 20 along the two longitudinal sides, and the column top retaining walls 20 are provided with brackets 21 for connection.

Specifically, the prefabricated top plate 12, namely a B block, comprises a B1 block located on a column top retaining wall 20 of the upper layer structure column 10 and a B2 block located on a bracket 21 of the prefabricated top longitudinal beam 17, wherein reinforcing steel bar connectors 22 are embedded in opposite side surfaces of the B1 block and the B2 block, and the reinforcing steel bar connectors 22 are used for reinforcing steel bar connection.

Specifically, the prefabricated top plate 12 is provided with tie bars 25, and the tie bars 25 are distributed at equal intervals.

Specifically, the assembled integral underground structure comprises a prefabricated structure and a cast-in-situ structure, wherein the prefabricated structure comprises prefabricated side walls 4, prefabricated lower-layer structural columns 5, prefabricated upper-layer structural columns 10, prefabricated middle plates 8, prefabricated top plates 12, prefabricated middle longitudinal beams 6 and prefabricated top longitudinal beams 17. The cast-in-situ structure comprises a bottom plate 2, a bottom longitudinal beam 3, a superposed middle longitudinal beam 9, a superposed top longitudinal beam 18, a superposed top plate 13 and an anti-cracking layer 14.

As shown in fig. 1 to 3, the prefabricated side wall 4 includes a partial top plate and a partial bottom plate, and the plate ends are located at the positions with smaller bending moment. As shown in fig. 1.

Specifically, the prefabricated side walls 4, the prefabricated middle longitudinal beam 6 and the prefabricated top longitudinal beam 17 are all provided with brackets 21 on the side parts. The prefabricated side wall 4 and the prefabricated middle plate 8 are longitudinally divided into rings, and connecting holes between the rings are reserved. Grooves are reserved at the splicing surfaces of the prefabricated side walls 4 and the prefabricated top plate 12.

Specifically, the tops of the lower layer structure column 5 and the upper layer structure column 10 are respectively provided with a column cap 24, and the column caps 24 are longitudinally provided with retaining walls 20. And grouting jacks into which main structural column ribs 19 are anchored are reserved at the upper parts of the side sill 3 and the lower structural column 5.

Specifically, the prefabricated middle longitudinal beams 6 of each span are respectively erected on the column caps 24 of the lower layer structural columns 5 of each span, a space for the upper layer structural columns 5 is reserved between the front prefabricated middle longitudinal beams 6 and the rear prefabricated middle longitudinal beams 6 on the column caps, and the left-right movement of the prefabricated middle longitudinal beams 6 is limited by utilizing the column top retaining walls 20 on the two sides of the column caps 24. Similarly, each span of prefabricated top longitudinal beam 17 is respectively erected on a column cap 24 of each span of prefabricated upper layer structural column 10, a space of the upper layer structural column 10 is reserved between the front prefabricated top longitudinal beam 17 and the rear prefabricated top longitudinal beam 17 on the column cap, and the prefabricated top longitudinal beam 17 is limited to move left and right by utilizing two side column top retaining walls 20 on the column cap 24.

Specifically, the prefabricated side wall 4 ring and the prefabricated middle plate 8 ring are longitudinally and firmly connected through the prestress of the finish rolling deformed steel bars 7.

In particular, the prefabricated central longitudinal beam 6 is erected on the cap 24 of the prefabricated substructure column 5. One side of the prefabricated middle plate 8 is placed on the bracket of the prefabricated side wall 4 and is connected with the bracket 21 through a sleeve, the other side of the prefabricated middle plate 8 is placed on the bracket 21 of the prefabricated middle longitudinal beam 6 or on the column top retaining wall 20 of the lower layer structural column 5, and a jacking device is additionally arranged between the left prefabricated middle plate 8 and the right prefabricated middle plate 8.

Specifically, the prefabricated middle plate 8, the prefabricated middle longitudinal beam 6, the superposed middle longitudinal beam 9 and the upper and lower layer structure column node column nodes are integrally poured to form a consolidation node.

Specifically, the prefabricated top longitudinal beam 17 is erected on the column cap 24 of the prefabricated upper layer structural column 10, one side of the prefabricated top plate 12 is placed on the bracket 21 of the prefabricated side wall 4 and is connected with the prefabricated side wall 4 through bolts, and the other side of the prefabricated top longitudinal beam is placed on the bracket 21 of the prefabricated top longitudinal beam 17 or the column top retaining wall 20 of the upper layer structural column 10.

Specifically, the prefabricated roof panel 12 is reserved with anchor bars anchored into the composite roof rail 18, and the main bars of the superstructure column 10 are connected with the long column top main bars in a connector connection manner and anchored into the composite roof rail 18. The laminated roof rail 18 is concrete-cast integrally with the roof laminated layer 13. The roof structure between the roof of the side wall part and the side wall is connected into an integrated structure through post-tensioning prestressing.

Specifically, elastic sealing gaskets are adhered in longitudinal grooves of the prefabricated side walls 4 and the prefabricated top plates 12 in the range of the top plate prefabricated plates, and prestress is applied between the left prefabricated top plate 12 and the right prefabricated top plate 12 so that the elastic sealing gaskets of the prefabricated side walls 4 and the prefabricated top plates 12 are pressed and closely adhered.

Specifically, the elastic sealing gasket is stuck to the annular groove of the prefabricated top plate 12, the prefabricated top plate 12 of the next ring and the prefabricated top plate 12 spliced by the previous ring are screwed and connected through penetrating the finish rolling screw steel 7 through the longitudinal connecting hole, and the elastic sealing gasket is pressed and closely stuck between the two rings to play a role of water stopping.

Specifically, the reinforcing steel bars of the top plate overlapping layer 13 between the top ends of the prefabricated side walls are connected with the reserved reinforcing steel bar connector of the prefabricated side walls 4, water stop adhesive tapes are adhered to the longitudinal grooves of the prefabricated side walls within the range of the top plate overlapping layer 13, and the top plate overlapping layer 13, the overlapping top longitudinal beams 18 and the beam column joint concrete at the top plate are poured simultaneously.

According to the assembled integral type underground structure, the prefabricated component is assembled into a whole and part of the cast-in-place concrete structure, the waterproof effect of the annular surface joint, the waterproof effect of the longitudinal joint and the waterproof effect of the top and bottom plates are enhanced, and the prefabricated component can be applied to areas with abundant groundwater.

A construction method for assembling an integral underground structure comprises the following steps:

A. building an enclosure structure and excavating a foundation pit;

B. Symmetrically splicing prefabricated side walls 4 left and right in the foundation pit;

C. a bottom plate 2 and a bottom girder 3 are applied;

D. Lowering a prefabricated lower layer structure column 5;

E. erecting a prefabricated middle longitudinal beam 6 of each span, and erecting a prefabricated middle plate 8;

F. Binding reinforcing steel bars of the overlapped middle longitudinal beam 9, connecting upper main ribs of the left and right prefabricated middle plates, and lowering prefabricated upper structural columns 10;

G. Pouring and overlapping the middle longitudinal beam 9;

H. erecting prefabricated top stringers 17 of each span in turn;

I. Erecting prefabricated top plates 12 on two sides of a prefabricated top longitudinal beam 17;

J. The upper main ribs of the left and right prefabricated top plates 12 are connected, the main ribs of the tops of the upper structural columns 10 are connected in a connector connection mode, and the reinforcing steel bars of the top plate overlapping layers 13 and the overlapping top longitudinal beams 18 are bound;

K. pouring a roof laminated layer 13 and a laminated roof longitudinal beam 18;

and L, carrying out prestress tensioning, constructing an upper layer structure and backfilling.

Furthermore, the step A is applied as an enclosure structure, and a foundation pit is excavated, and the concrete process is as follows:

Firstly, constructing a surrounding fence, leveling a field, and performing traffic fluffing;

Then, building an enclosure structure 1;

then, dewatering in the foundation pit until the dewatering depth reaches the design requirement;

Then excavating a foundation pit, erecting a transverse steel pipe support 26 along with the excavation until the foundation pit is excavated to the bottom;

Then, paving a bottom plate cushion layer at the bottom of the foundation pit;

and finally, paving a bottom plate waterproof layer on the bottom plate cushion layer.

Furthermore, the step B is to assemble the prefabricated side wall 4 in the foundation pit in a bilateral symmetry manner, and the concrete process is as follows:

Firstly, dismantling the upper steel pipe support 26 and the lower steel pipe support 26 in a first vertical direction by utilizing the space supporting effect of a foundation pit;

Then, splicing prefabricated side walls 4 with the width of 1.5 meters and 2 blocks symmetrically;

Then, prestress is applied between the longitudinal prefabricated side walls 4, and the longitudinal prefabricated side walls are screwed and connected into a whole by using finish rolling deformed steel bars 7;

And finally, assembling and constructing the side wall according to the steps.

More specifically, steel support changing 27 is arranged between the enclosure structures 1 and between the prefabricated side walls 4.

More specifically, when the prefabricated side wall 4 is assembled, an elastic sealing gasket is adhered to the annular groove of the prefabricated side wall 4, the prefabricated side wall of the next ring and the prefabricated side wall 4 spliced by the previous ring are screwed and extruded to be connected through the longitudinal connecting hole penetrating the finish rolling screw steel 7, and the elastic sealing gasket is extruded and closely adhered between the two rings to play a role of water stop.

Specifically, step C is performed on the bottom plate 2 and the side sill 3, and the specific process is as follows:

Firstly, a cast-in-situ bottom plate 2 and a bottom girder 3;

then, a grouting jack is reserved in the bottom longitudinal beam 3, and the grouting jack is opposite to the main structural column rib 19 of the lower structural column 5.

More specifically, the bottom plate steel bars between the prefabricated side walls 4 are connected with the bottom plate steel bar connector 22 reserved by the prefabricated side walls 4, and the bottom plate 2 and the bottom longitudinal beam 3 are cast in situ at the same time.

Specifically, step D lowers the prefabricated lower layer structural column 5, and the specific process is as follows:

firstly, grouting and filling grouting jacks of the side sill 3;

Then, the prefabricated lower structural column 5 is lowered so that the structural column main rib 19 is inserted into the grouting insertion hole.

More specifically, the grouting insertion holes of the side sill 3 are inserted with the main structural column ribs 19 of the lower structural column 5 before the cement slurry is initially set.

Similarly, the grouting jack at the top of the lower structural column 5 is inserted with the main structural column rib 19 of the upper structural column 10 before the cement slurry is initially set.

Specifically, step E erects prefabricated middle stringers 6 of every span, establishes prefabricated medium plate 8, and the specific process is as follows:

firstly, erecting a bridge girder erection machine by utilizing a shield well platform, and erecting prefabricated middle stringers 6 of each span;

Then, each time a span prefabricated middle longitudinal beam 6 is erected, the prefabricated middle plates 8 on the two sides are erected on brackets 21 of the prefabricated middle longitudinal beam 6 and the prefabricated side walls 4;

then, the finish-rolled deformed steel bar 7 in the longitudinal direction is screwed;

Finally, the circumferential bolts at the bracket 21 are screwed.

Specifically, step F binds the reinforcing steel bars of the middle longitudinal beam 9 in the superposition, connects the upper main bars of the left and right prefabricated middle plates, and lowers the prefabricated superstructure column 10, and the specific process is as follows:

Firstly, binding reinforcing steel bars of the middle longitudinal beam 9 and stirrups of a cast-in-situ layer of a lower column position;

then, the prefabricated superstructure column 10 is lowered, and the grouting holes are filled with grouting material for compaction.

Specifically, the step G of pouring the middle longitudinal beam 9 in lamination includes the following steps:

first, the overlapping part of the overlapping middle longitudinal beam 9 and the joint wet joint of the upper layer structural column 10 and the overlapping middle longitudinal beam 9 are poured, and the prefabricated middle plate 8 and the overlapping middle longitudinal beam 9 are fixedly connected into a whole.

Then, after the design strength is reached, the third steel change stay 27 is removed.

Specifically, step H sequentially erects prefabricated roof stringers 17 for each span, and the specific process is as follows:

And erecting a bridge girder erection machine by utilizing a shield well platform, and erecting prefabricated top stringers 17 of each span in sequence.

Specifically, step I establishes prefabricated roof panels 12 on both sides of prefabricated roof rail 17, and the specific process is as follows:

firstly, each time a span of prefabricated top longitudinal beams 17 is erected, the prefabricated top plates 12 on two sides are erected on bracket 21 of the prefabricated top longitudinal beams 17;

then, the prefabricated top plates 12 are screwed by using finish rolling deformed steel bars 7, and the prefabricated top plates 12 and the prefabricated side walls 4 are connected by using circumferential bolts 11.

Specifically, the step K is to pour the roof laminated layer 13 and the laminated roof rail 18, and the specific process is as follows:

Firstly, connecting the reinforcing steel bars of the left and right prefabricated top plates 12, connecting the main column top bars of the upper layer structure column 10 in a connector connection mode, and binding the reinforcing steel bars of the top plate superposition layer 13 and the superposition top longitudinal beam 18;

then, roof slab laminate 13 and laminate roof rail 18, as well as beam column node concrete, are poured.

Specifically, the step L is prestressed and tensioned, the superstructure is constructed and backfilled, and the concrete process is as follows:

firstly, penetrating a prestress steel strand, tensioning, locking, grouting and sealing an anchor;

then, pouring a concrete anti-cracking layer 14, a waterproof layer 15 and a waterproof protective layer 16;

and finally, backfilling and supporting disassembly are carried out.

The above embodiments are only for illustrating the technical aspects of the present utility model and not for limiting the same, and although the present utility model has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the utility model without departing from the spirit and scope of the utility model, which is intended to be covered by the claims.

Claims (7)

1. An assembled integral underground structure, comprising prefabricated side walls (4), characterized in that: the prefabricated side walls (4) are arranged in a cast-in-situ bottom plate structure at the lower part, a prefabricated middle plate structure at the middle part is arranged between the prefabricated side walls (4), a top plate structure which is arranged at the top and is formed by prefabricating and cast-in-situ superposition is arranged between the prefabricated side walls (4), a vertically supported lower layer structure column (5) is arranged between the cast-in-situ bottom plate structure and the prefabricated middle plate structure, a vertically supported upper layer structure column (10) is arranged between the prefabricated middle plate structure and the top plate structure, a prefabricated middle longitudinal beam (6) and a superposition middle longitudinal beam (9) are arranged at the top of the lower layer structure column (5) to form an integrated middle longitudinal beam, and a prefabricated top longitudinal beam (17) and a superposition top longitudinal beam (18) are arranged at the top of the upper layer structure column (10) to form an integrated top longitudinal beam.

2. A fabricated monolithic underground structure according to claim 1, wherein: the cast-in-situ bottom plate structure comprises a cast-in-situ bottom plate (2) and a cast-in-situ bottom longitudinal beam (3), wherein the bottom longitudinal beam (3) is positioned in the middle of the bottom plate (2).

3. A fabricated monolithic underground structure according to claim 1, wherein: the upper end of the lower layer structure column (5) is provided with a prefabricated middle longitudinal beam (6), and the prefabricated middle longitudinal beam (6) and the prefabricated side wall (4) provide supporting conditions for the prefabricated middle plate structure.

4. A fabricated monolithic underground structure according to claim 1, wherein: the prefabricated middle plate structure comprises a prefabricated middle plate (8), and the prefabricated middle plate (8) is erected on brackets (21) of the prefabricated middle longitudinal beam (6) and the prefabricated side wall (4).

5. A fabricated monolithic underground structure according to claim 1, wherein: the prefabricated middle longitudinal beam (6) is provided with a superposed middle longitudinal beam (9), the superposed middle longitudinal beam (9) is provided with an upper layer structure column (10), the upper end of the upper layer structure column (10) is provided with a prefabricated top longitudinal beam (17), and the prefabricated top longitudinal beam (17) and the prefabricated side wall (4) provide supporting conditions for a top plate structure.

6. A fabricated monolithic underground structure according to claim 5, wherein: the top plate structure comprises a prefabricated top plate (12), and the prefabricated top plate (12) is erected on bracket (21) at the tops of the prefabricated top longitudinal beam (17) and the prefabricated side wall (4).

7. A fabricated monolithic underground structure according to claim 6, wherein: the upper end of the prefabricated top plate (12) is provided with a cast-in-situ top plate laminated layer (13), a concrete anti-cracking layer (14) is arranged on the upper portion of the top plate structure, and a waterproof layer (15) and a waterproof protective layer (16) are sequentially arranged on the upper portion of the concrete anti-cracking layer (14).