Fabricated support structure for foundation pit and grouting construction method thereof

Abstract

The present application relates to the technical field of foundation pit support, and discloses a fabricated inner support structure of foundation pit and a grouting construction method thereof, which comprises a supporting part, a supporting part and a fixing part, the supporting part comprises a first supporting part and a plurality of second supporting parts, the fixing part comprises a first fixing part and a second fixing part, the supporting part, the supporting part and the fixing part all comprise a hollow shell, the shell is pre-assembled with reinforcing steel bars, the supporting part, the first supporting part, the second supporting part and the fixing part are all provided with interconnected communication holes, and the top of the first supporting part and the second fixing part is provided with a grouting hole. The overall structure of the foundation pit support is simplified, the reinforcing steel bars can directly form a steel reinforcement cage when preformed in the factory, the process of manually binding the steel reinforcement cage is avoided, the supporting part, the supporting part and the fixing part are hollow structures, the grouting process is reserved for on-site construction, the quality of the preformed parts in the factory is reduced, the cost of production and transportation is reduced, and lightweight production is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foundation pit support, in particular to an assembled inner support structure of foundation pit and a grouting construction method thereof. BACKGROUND

[0002] The assembled inner support of foundation pit is a new form of assembled building, which concentrates the steel bars and concrete of traditional construction method in the factory to produce prefabricated components in a streamlined manner, and the main structure is finally assembled at the construction site. The assembled building enables the construction and production of building structure to be factory-based. Compared with the traditional cast-in-place inner support structure, the assembled inner support of foundation pit has the advantages of high efficiency, controllable quality, energy saving and environmental protection, etc.

[0003] Since the assembled inner support of foundation pit is assembled by multiple concrete segments, the existing assembled inner support of foundation pit generally requires to provide greater support capacity for engineering needs. The oversized and heavy prefabricated components pose new challenges to the production, transportation and assembly of assembled components, and bring great difficulties to the site construction. Therefore, it is of great practical significance and engineering application value to study the lightweight structure design and construction method of assembled components. SUMMARY

[0004] The purpose of the present application is to provide an assembled inner support structure of foundation pit to meet the lightweight requirement of assembled building, and further provide a grouting construction method of the assembled inner support structure of foundation pit.

[0005] In order to achieve the above purpose, the present application provides an assembled inner support structure of foundation pit, comprising:

[0006] A supporting member for supporting at the bottom of the foundation pit;

[0007] A support member comprising a first support part supported on the supporting member and a plurality of second support parts arranged at the end of the first support part, each of the second support parts being used for laterally supporting the side wall of the foundation pit;

[0008] A fixing member corresponding to each of the second support parts, the second support part being arranged between the fixing member and the side wall of the foundation pit, the fixing member comprising a first fixing part arranged at the lower side of the first support part and a second fixing part arranged at the upper side of the first support part, the first fixing part and the second fixing part being used for fixedly connecting with the side wall of the foundation pit;

[0009] The supporting member, the supporting member and the fixing member all comprise a hollow shell, the shell is pre-assembled with reinforcing steel bars, the shell of the first supporting part and the shell of the second supporting part are mutually penetrated, the shells of the supporting member, the first supporting part and the second supporting part are all provided with communicating holes which are mutually communicated, and the top of the first supporting part and the second fixing part are both provided with grouting holes for on-site grouting.

[0010] Preferably, the first supporting part is a plate-shaped structure horizontally arranged at the top of the supporting member, both ends of the first supporting part are arranged with the second supporting part, and the first supporting part and the second supporting part form a I-shaped structure.

[0011] Preferably, the first fixing part and the second fixing part both comprise a horizontal segment and a vertical segment which are connected into an L shape, the horizontal segment is used for fixedly connecting with the side wall of the foundation pit, the horizontal segment of the first fixing part is supported at the bottom of the second supporting part, the horizontal segment of the second fixing part is buckled at the top of the second supporting part, and the distance between the bottom surface of the horizontal segment of the first fixing part and the first supporting part is equal to the distance between the top surface of the horizontal segment of the first fixing part and the second fixing part.

[0012] Preferably, the thickness of the horizontal segment of the first fixing part in the vertical direction is greater than the thickness of the horizontal segment of the second fixing part in the vertical direction.

[0013] Preferably, the steel bar density of the horizontal segment of the first fixing part is greater than the steel bar density of the vertical segment of the first fixing part, and the steel bar density of the horizontal segment of the second fixing part is greater than the steel bar density of the vertical segment of the second fixing part.

[0014] Preferably, the horizontal segment is embedded into the side wall of the foundation pit, and the horizontal segment and the side wall of the foundation pit are fixedly connected through bolts.

[0015] Preferably, the supporting member is a trapezoidal structure with gradually increasing cross sections from top to bottom, and the bottom of the supporting member is bolted with the bottom wall of the foundation pit.

[0016] Preferably, the steel bar density of the supporting member below the projection plane of the top surface is greater than the steel bar density of the supporting member on both sides of the projection plane of the top surface.

[0017] The application also provides a grouting construction method of the fabricated inner support structure of the foundation pit, which is applied to the fabricated inner support structure of the foundation pit in any of the above technical solutions and comprises the following steps.

[0018] S1, the support piece, the first fixed part is assembled in the designated position of the foundation pit respectively, and then connected and installed, and then the support piece is supported and arranged on the support piece, and the communication holes among the support piece, the support piece and the first fixed part are communicated with each other;

[0019] S2, grouting is carried out through the grouting hole on the support piece, and the slurry flows into the support piece and the first fixed part in turn under the action of gravity, and the grouting is stopped when the slurry in the shell is flush with the grouting hole at the top of the support piece;

[0020] S3, after the support piece and the first fixed part are cured, the second fixed part is hoisted, the second fixed part is assembled on the upper side of the second support part, and the second fixed part is connected with the side wall of the foundation pit;

[0021] S4, grouting is carried out through the grouting hole at the top of the second fixed part, and the slurry flows into the support piece and the second fixed part in turn under the action of gravity, and the grouting is stopped when the slurry is flush with the grouting hole at the top of the second fixed part, and the various structural parts are cured.

[0022] Preferably, the step S5 of reinforcing the joint between the support piece, the support piece and the fixed part after standing curing is further included.

[0023] Compared with the prior art, the assembly type foundation pit inner support structure and the grouting construction method thereof have the beneficial effects that the foundation pit support is divided into a support piece, a support piece and a fixed part, the overall structure of the foundation pit support is simplified, the support piece, the support piece and the fixed part are conveniently formed into a streamline in the factory, the support piece, the support piece and the fixed part are formed by a shell and internal reinforcing steel bars, and the grouting hole is reserved on the support piece and the first fixed part, the communication holes among the various structural parts are communicated, the reinforcing steel cage can be directly formed by the reinforcing steel bars when the support piece, the support piece and the fixed part are prefabricated in the factory, the process of manually binding the reinforcing steel cage is avoided, the support piece, the support piece and the fixed part are hollow structures, the grouting process is reserved for on-site construction, the quality of the prefabricated parts in the factory is reduced, the cost of production and transportation is reduced, the time of transporting the prefabricated parts from the factory to the site after production and curing is saved, the construction efficiency is improved, lightweight production is realized, and the construction efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic view of the assembly type foundation pit inner support structure of the application;

[0025] Figure 2 is a structural schematic view of the assembly type foundation pit inner support structure of the application; Figure 1

[0026] Figure 3 is a structural schematic view of the assembly type foundation pit inner support structure of the application; Figure 1 ​​

[0027] Figure 4 is a structural schematic diagram of the assembled inner support structure of the foundation pit and the structure after the foundation pit is assembled;

[0028] Figure 5 is Figure 1 a structural schematic diagram of the reinforced steel of the assembled inner support structure of the foundation pit.

[0029] In the figure, 1, a supporting piece, 2, a supporting piece, 21, a first supporting part, 22, a second supporting part, 3, a fixing piece, 31, a first fixing part, 32, a second fixing part, 4, a reinforcing steel, 5, a grouting hole, 6, a communication hole, 7, a foundation pit. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application will be further described in detail below in combination with the drawings and examples. The following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0031] A preferred embodiment of the assembled inner support structure of the foundation pit of the present application is shown in Figures 1 to 5 The assembled inner support structure of the foundation pit includes a supporting piece 1, a supporting piece 2 and a fixing piece 3, the supporting piece 1 is used to support the bottom of the foundation pit 7, and plays a supporting and fixing role for the whole foundation pit support, the supporting piece 2 is used to support the side wall of the foundation pit 7, and the fixing piece 3 is used to be fixedly connected with the side wall of the foundation pit 7 to fix the supporting piece 2 with the side wall of the foundation pit.

[0032] The supporting piece 2 includes a first supporting part 21 and a second supporting part 22, the first supporting part 21 is horizontally supported on the supporting piece 1 to transmit the acting force to the supporting piece 1, and the second supporting part 22 is vertically arranged at the end of the first supporting part 21 to fit and laterally support the side wall of the foundation pit, the acting force on the second supporting part 22 is transmitted to the supporting piece 1 through the first supporting part 21, and then to the bottom of the foundation pit by the supporting piece 1. The second supporting part 22 has a plurality of, and the specific number is adjusted according to the number of the side wall of the foundation pit.

[0033] The fixing piece 3 has a plurality of, and the fixing piece 3 corresponds to the second supporting part 22 of the supporting piece 2 one by one, and the second supporting part 22 is arranged between the fixing piece 3 and the side wall of the foundation pit. After the fixing piece 3 is fixed with the side wall of the foundation pit, the second supporting part 22 is laterally extruded on the side wall of the foundation pit, so as to fix the second supporting part 22, and the fixing piece 3 can bear the lateral acting force transmitted by the second supporting part 22, support and fix the second supporting part 22 while bearing the lateral acting force, and eliminate the eccentric force of the foundation pit acting on the whole supporting piece 2.

[0034] The fixing member 3 comprises a first fixing part 31 arranged at the lower side of the first supporting part 21 and a second fixing part 32 arranged at the upper side of the first supporting part 21, and both the first fixing part 31 and the second fixing part 32 are used for fixed connection with the side wall of the foundation pit to fix the second supporting part 22 located between the fixing member 3 and the side wall of the foundation pit. The first fixing part 31 can provide vertical supporting force for the support member 2 above it, and the second fixing part 32 eliminates the eccentric force acting on the support member 2 by laterally extruding the second supporting part 22, thereby avoiding deflection of the second supporting part 22.

[0035] The support member 1, the support member 2 and the fixing member 3 all comprise a hollow shell, and a reinforcing steel bar 4 is pre-assembled in the shell. The hollow inner cavity of the shell is used for flow of grout for field grouting. The reinforcing steel bar 4 plays a role of tightening the cage and is mixed with the grout to form a reinforced concrete structure, thereby increasing the strength of the support member 1, the support member 2 and the fixing member 3. Meanwhile, the steel bar is assembled in the shell, which can be processed and formed in a production line in a factory, thereby reducing the workload of on-site tightening. In the embodiment, the shell is a steel shell with a certain thickness, and the thickness of the steel shell can be calculated and adjusted as needed. The steel shell plays a role of waterproofing and providing bearing capacity.

[0036] The shell of the first supporting part 21 and the shell of the second supporting part 22 are mutually penetrated. In the embodiment, the cavities of the shells of the first supporting part 21 and the second supporting part 22 are in a communication state, and the shells are smoothly transitioned to connect the first supporting part 21 and the second supporting part 22 as a whole during grouting, thereby increasing the overall strength of the support member 2 and facilitating transmission of the force borne by the second supporting part 22 to the first supporting part 21 and then to the support member 1.

[0037] The shells of the support member 1, the first supporting part 21 and the second supporting part 22 are mutually penetrated, and the shells of the second supporting part 22 and the fixing member 3 are also mutually penetrated. The communication holes 6 make the cavities in the shells mutually communicate, and the grout can sequentially fill the cavities in the shells under the action of gravity during grouting. Meanwhile, the communication holes 6 can also be used as air vents and observation holes during grouting, and the communication holes 6 have a positioning effect between the support member 1, the support member 2 and the fixing member 3, thereby facilitating assembly and connection of the structural members. The grout flows under the action of gravity, and in order to ensure that the grout sequentially fills the structural members from bottom to top during grouting, the communication holes 6 are arranged at the positions where the shells of two structural members horizontally contact each other.

[0038] The top of the first support part 21 and the second fixing part 32 is provided with a grouting hole 5 for on-site grouting. The diameter of the grouting hole 5 is slightly larger than the nozzle diameter of the electric grouting machine for grouting, so that the grouting hole 5 can also be used as a ventilation hole and an observation hole. During grouting, the gas is continuously extruded under the action of the slurry, and the excess gas can be discharged through the grouting hole 5 and the communication hole 6. When the slurry is about to reach the upper surface of each component, the grouting process can be stopped by observing whether the slurry overflows the observation hole through the grouting hole 5. In this embodiment, the difference between the diameter of the grouting hole 5 and the nozzle diameter of the electric grouting machine is in the range of 0.1m-0.2m, which ensures ventilation and observation while reducing the nozzle swing of the electric grouting machine.

[0039] The assembled foundation pit support structure divides the foundation pit support into a supporting part 1, a support part 2 and a fixing part 3, simplifies the overall structure of the foundation pit support, facilitates the flow line prefabrication in the factory, and the supporting part 1, the support part 2 and the fixing part 3 are formed by a shell and internal reinforcing steel bars 4, and grouting holes 5 are reserved on the support part 2 and the first fixing part 31, and the structures are communicated through communication holes 6. When prefabricated in the factory, the reinforcing steel bars 4 can directly form a steel cage, avoiding the process of manually binding the steel cage. Meanwhile, the supporting part 1, the support part 2 and the fixing part 3 are hollow structures, the grouting process is reserved for on-site construction, the quality of the prefabricated parts in the factory is reduced, the cost of production and transportation is reduced, lightweight production is realized, and the efficiency of on-site construction is improved.

[0040] Preferably, the first support part 21 is a plate-shaped structure horizontally arranged on the top of the supporting part 1, both ends of the first support part 21 are arranged with the second support part 22, and the first support part 21 and the second support part 22 form an I-shaped structure.

[0041] The first support part 21 and the two second support parts 22 form an I-shaped structure, the I-shaped structure has good stability, and the upper and lower sides of the two second support parts 22 can laterally support the side wall of the foundation pit, the horizontal forces received by the two sides can cancel each other out to increase the stability.

[0042] Preferably, the first fixing part 31 and the second fixing part 32 each include a horizontal segment and a vertical segment connected to each other in an L shape, the horizontal segment is used for fixed connection with the side wall of the foundation pit, the horizontal segment of the first fixing part 31 is supported on the bottom of the second support part 22, the horizontal segment of the second fixing part 32 is buckled on the top of the second support part 22, and the distance between the bottom surface of the horizontal segment of the first fixing part 31 and the first support part 21 is equal to the distance between the top surface of the horizontal segment of the second fixing part 32 and the first support part 21.

[0043] The first fixing part 31 and the second fixing part 32 are both formed by a horizontal section and a vertical section in L shape, which extrude the second supporting part 22 to the sidewall of the foundation pit, and support the foundation pit together with the second supporting part 22, and the horizontal section increases the contact area with the second supporting part 22, so that the second supporting part 22 is balanced in force.

[0044] The distance between the first supporting part 21 and the bottom surface of the horizontal section of the first fixing part 31 is equal to the distance between the first supporting part 21 and the top surface of the horizontal section of the second fixing part 32, so that the distance between the horizontal lateral force of the foundation pit to the first fixing part 31 and the first supporting part 21 is the same, that is, the bending moments generated by the two horizontal lateral forces are offset to each other, which eliminates the eccentric force of the wall surface to the I-shaped supporting part 2, so that the first fixing part 31 supports the first supporting part 21 while ensuring that the sidewall of the foundation pit only has a lateral axis force on the center line to the overall foundation pit support.

[0045] Preferably, the thickness of the horizontal section of the first fixing part 31 in the vertical direction is greater than the thickness of the horizontal section of the second fixing part 32 in the vertical direction.

[0046] The first fixing part 31 is located on the lower side of the first supporting part 21, so the horizontal section of the first fixing part 31 needs to bear greater vertical load, and thickening design can prevent the first fixing part 31 from breaking. At the same time, since the second fixing part 32 mainly bears the horizontal lateral force of the sidewall of the foundation pit transmitted through the second supporting part 22, the horizontal section of the second fixing part 32 does not need to be thickened, which can reduce the dead weight and production cost.

[0047] Since the thickness of the horizontal section of the first fixing part 31 is greater than the thickness of the horizontal section of the second fixing part 32, in order to ensure that the distance between the first supporting part 21 and the bottom surface of the horizontal section of the first fixing part 31 is equal to the distance between the first supporting part 21 and the top surface of the horizontal section of the second fixing part 32, the supporting part 2 is an asymmetric structure in the up-down direction, that is, the second supporting part 22 is asymmetric in the up-down direction with the first supporting part 21 as the axis, and the height of the second supporting part 22 on the upper side of the first supporting part 21 is greater than the height of the second supporting part 22 on the lower side of the first supporting part 21.

[0048] Preferably, the steel reinforcement density of the horizontal section of the first fixing part 31 is greater than the steel reinforcement density of the vertical section of the first fixing part 31, and the steel reinforcement density of the horizontal section of the second fixing part 32 is greater than the steel reinforcement density of the vertical section of the second fixing part 32.

[0049] The horizontal section of the first fixed part 31 and the horizontal section of the second fixed part 32 are main force bearing parts, and the steel bar density of the parts is increased to provide sufficient bearing capacity; the vertical section of the first fixed part 31 and the vertical section of the second fixed part 32 are structural parts, and the steel bar density of the structural parts can be reduced within the safety strength, so that the weight of each structural part is reduced, and lightweight production is realized.

[0050] Preferably, the horizontal section is embedded in the side wall of the foundation pit, and the horizontal section and the side wall of the foundation pit are connected by bolt fixing.

[0051] The horizontal section is embedded in the side wall of the foundation pit, which can position the horizontal section and support the horizontal section by the side wall of the foundation pit, thereby increasing the stability of the foundation pit support. As a common structure for construction connection, the bolt connection can be connected by pre-buried structural parts in the side wall of the foundation pit, which simplifies the connection structure of the fixed part 3 and the foundation pit and ensures the connection strength.

[0052] Preferably, the support part 1 is a trapezoidal structure with gradually increasing cross section from top to bottom, and the bottom of the support part 1 is connected to the bottom wall of the foundation pit by bolt.

[0053] Compared with a rectangle, the trapezoidal support part 1 can effectively reduce the pressure on the ground, reduce ground subsidence, enhance the anti-interference ability of circumferential shaking, and improve the support stability. The support part 1 is connected to the bottom wall of the foundation pit by bolt, and the bottom wall of the foundation pit can be pre-buried with structural parts to realize fixation, thereby simplifying the connection structure of the support part 1.

[0054] Preferably, the steel bar density of the support part 1 below the projection plane of the top surface is greater than the steel bar density on both sides of the projection plane of the top surface.

[0055] The projection plane of the top surface of the support part 1 mainly bears the vertical force of the entire foundation pit support, and the parts on both sides of the projection plane of the top surface can increase the base area of the bottom wall of the foundation pit, thereby reducing the pressure and subsidence. Therefore, the steel bar density of the support part 1 below the projection plane of the top surface is increased to provide better bearing capacity, and the steel bar density on both sides of the projection plane of the top surface is reduced to reduce the weight of the support part 1.

[0056] The preferred embodiment of the grouting construction method of the fabricated inner support structure of the foundation pit of the present application comprises the following steps:

[0057] S1, the support part and the first fixed part are respectively assembled and connected at the specified positions of the foundation pit, and then the support part is supported and arranged on the support part, so that the communication holes among the support part, the support part and the first fixed part are communicated with each other;

[0058] S2, grouting is performed through the grouting hole on the support part, and the grout flows through the communication holes under the action of gravity to fill the support part and the first fixed part in sequence, and the grouting is stopped when the grout in the shell is flush with the grouting hole at the top of the support part.

[0059] S3, after the maintenance of the supporting part and the first fixing part is completed, hoisting the second fixing part, assembling the second fixing part on the upper side of the second supporting part, connecting the second fixing part with the side wall of the foundation pit;

[0060] S4, grouting through the grouting hole at the top of the second fixing part, under the action of gravity, the slurry flows through the communication hole and fills the supporting part and the second fixing part in turn, and the grouting is stopped when the slurry is flush with the grouting hole at the top of the second fixing part, and the maintenance of each structural part is carried out.

[0061] In step S1, the assembly is carried out according to the principle of from bottom to top, the supporting part is hoisted first, then the first fixing part is hoisted after the installation of the supporting part is completed, the first fixing part is positioned and fixed by being embedded in the mortise on the side wall of the foundation pit, then the supporting part is hoisted, and the supporting part is positioned and connected with the supporting part and the first fixing part through the communication hole.

[0062] In step S2, when the slurry is flush with the grouting hole at the top of the supporting part, the cavity in the second supporting part of the supporting part on the upper side of the first supporting part is not injected with the slurry, and the cavity not injected with the slurry is filled with the slurry from the second fixing part during grouting in step S4, so that the slurry enters the second supporting part of the supporting part first during grouting in step S4, and then the second fixing part is filled after the grouting of the second supporting part is completed. During on-site grouting, distributed pouring forming is adopted to facilitate hoisting.

[0063] Preferably, step S5 of reinforcing the joint between the supporting part, the supporting part and the fixing part after static curing is further included.

[0064] The joint is reinforced, and the overall reliability of the foundation pit support is improved.

[0065] In summary, the embodiment of the present application provides an assembled foundation pit inner support structure and a grouting construction method thereof, which divides the foundation pit support into a supporting part, a supporting part and a fixing part, simplifies the overall structure of the foundation pit support, facilitates the flow line prefabrication in the factory, the supporting part, the supporting part and the fixing part are formed by the shell and the internal reinforcing steel bars, and the grouting hole is reserved on the supporting part and the first fixing part, and the communication holes are communicated between the structural parts. When prefabricated in the factory, the reinforcing steel cage can be directly formed by the reinforcing steel bars, avoiding the process of manually binding the reinforcing steel cage, and the supporting part, the supporting part and the fixing part are hollow structures, the grouting process is reserved for on-site construction, the quality of the prefabricated parts in the factory is reduced, the cost of production and transportation is reduced, the time of transportation from the factory after production and maintenance is saved, the construction efficiency is improved, the lightweight production is realized, and the construction efficiency is improved.

[0066] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and replacements can be made without departing from the technical principles of the present application, and these improvements and replacements should also be considered as the protection scope of the present application.

Claims

1. A fabricated bracing structure for a foundation pit, characterized by, The utility model relates to a support structure of foundation pit, including: a supporting piece for supporting at the bottom of a foundation pit; a support piece including a first support part supported on the supporting piece and a plurality of second support parts arranged at the ends of the first support part, each of the second support parts for laterally supporting the sidewall of the foundation pit; a fixing piece corresponding to the second support part, the second support part being arranged between the fixing piece and the sidewall of the foundation pit, the fixing piece including a first fixing part arranged at the lower side of the first support part and a second fixing part arranged at the upper side of the first support part, the first fixing part and the second fixing part both for fixed connection with the sidewall of the foundation pit; the supporting piece, the support piece and the fixing piece all include a hollow shell, the shell is pre-assembled with reinforcing steel bars, the shells of the first support part and the second support part are mutually penetrated, the shells of the supporting piece, the first support part and the second support part are all provided with communicating holes for mutual communication, and the first support part and the top of the second fixing part are both provided with grouting holes for on-site grouting.

2. The fabricated bracing structure for a foundation pit according to claim 1, wherein the first support part is a plate-shaped structure horizontally arranged at the top of the supporting piece, both ends of the first support part are provided with the second support parts, and the first support part and the second support parts form an I-shaped structure.

3. The fabricated bracing structure for a foundation pit according to claim 2, wherein the first fixing part and the second fixing part both include a horizontal section and a vertical section connected in an L shape, the horizontal section is for fixed connection with the sidewall of the foundation pit, the horizontal section of the first fixing part is supported at the bottom of the second support part, the horizontal section of the second fixing part is buckled at the top of the second support part, and the distance between the bottom surface of the horizontal section of the first fixing part and the first support part is equal to the distance between the top surface of the horizontal section of the first fixing part and the second fixing part.

4. The assembled inner support structure of the foundation pit according to claim 3, wherein, the thickness of the horizontal section of the first fixing part in the vertical direction is greater than the thickness of the horizontal section of the second fixing part in the vertical direction.

5. The assembled inner support structure of the foundation pit according to claim 4, wherein, the steel bar density of the horizontal section of the first fixing part is greater than the steel bar density of the vertical section of the first fixing part, and the steel bar density of the horizontal section of the second fixing part is greater than the steel bar density of the vertical section of the second fixing part.

6. The assembled inner support structure of the foundation pit according to claim 3, wherein, the horizontal section is embedded into the sidewall of the foundation pit, and the horizontal section and the sidewall of the foundation pit are fixedly connected through bolts.

7. The assembled bracing structure for an excavation according to any one of claims 1 to 6, wherein the supporting piece is a trapezoidal structure with gradually increasing cross sections from top to bottom, and the bottom of the supporting piece is bolted to the bottom wall of the foundation pit.

8. The assembled inner support structure of a foundation pit according to claim 7, wherein, the steel bar density of the supporting piece below the projection plane of the top surface is greater than the steel bar density on both sides of the projection plane of the top surface.

9. A grouting construction method applied to the fabricated inner support structure of any one of claims 1-8, characterized in that, the utility model relates to a support structure of foundation pit, including: S1, the supporting piece, the first fixing part are assembled respectively at the specified position of the foundation pit and are connected and installed, then the support piece is supported and arranged on the supporting piece, and the communicating holes among the supporting piece, the support piece and the first fixing part are mutually communicated; S2, grouting is carried out through the grouting hole on the support piece, and the slurry flows and fills the supporting piece, the first fixing part in turn through the communicating holes under the action of gravity, and the grouting is stopped when the slurry in the shell is flush with the grouting hole at the top of the support piece. S3, after the maintenance of the supporting member and the first fixing part is completed, hoisting the second fixing part, assembling the second fixing part on the upper side of the second supporting part, connecting the second fixing part with the side wall of the foundation pit; S4, through the grouting hole on the top of the second fixing part, grouting, under the action of gravity, the slurry flows through the communication hole in turn to fill the supporting member and the second fixing part, and the grouting is stopped when the slurry is flush with the grouting hole on the top of the second fixing part, and each structure is maintained.

10. The slip casting method of claim 9, wherein, It also includes step S5, reinforcing the joint between the supporting member, the supporting member and the fixing member after the curing.

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