CN118273347A

CN118273347A - Foundation pit supporting system

Info

Publication number: CN118273347A
Application number: CN202410555867.7A
Authority: CN
Inventors: 刘群辉; 郑晓俊
Original assignee: Taizhou Xin'an Construction Co ltd
Current assignee: Taizhou Xin'an Construction Co ltd
Priority date: 2024-05-07
Filing date: 2024-05-07
Publication date: 2024-07-02

Abstract

The invention provides a foundation pit supporting system, which belongs to the technical field of foundation pit construction, and comprises the steps of digging a foundation pit in a construction area by utilizing large-scale mechanical equipment, then using a total station and a precise level to fix points and position on the bottom wall of the foundation pit, using paint to draw lines in the fixed points and the positioning areas, drawing a projection area of a ring beam on the bottom wall of the foundation pit, uniformly positioning piling points of a plurality of locating piles in the projection area of the ring beam on the bottom wall of the foundation pit by using the total station, and fixing the locating piles in pile holes; after the cement mortar in the pile hole is hardened, a first layer of ring beam is built in a painted area of a painted line, meanwhile, the ring beam is built layer by layer from bottom to top by taking the first layer of ring beam as a reference until reaching the height required by a construction drawing, a reinforcing steel bar net is built on the outer side of the first layer of ring beam, a transport vehicle is used for pouring dregs between the ring beam and the side wall of a foundation pit, and then a road roller is used for compaction. The foundation pit supporting device can stably support and stabilize the foundation pit, and has high construction precision.

Description

Foundation pit supporting system

Technical Field

The invention relates to the technical field of foundation pit construction, in particular to a foundation pit supporting system.

Background

With the continuous development of the building industry, high-rise and super-high-rise buildings are more and more, the stability of the high-rise buildings depends on the foundation, foundation pits are needed to be excavated firstly before the foundation is built, however, in the process of excavation of the foundation pits, the phenomenon that soil mass around the foundation pits collapses easily occurs, and then the foundation pits are needed to be supported in time, in the prior art, the foundation pit supporting structure is five-flower eight-door, but most of the foundation pit supporting structures are temporary supporting, the corresponding supporting devices are abandoned after being used once, so that the resource waste is caused, and in addition, the common mode in the technology is enjoyed, the inner wall of the foundation pit is temporarily supported by adopting sprayed concrete.

Disclosure of Invention

The invention aims to provide a foundation pit supporting system which can stably support a foundation pit, stabilize a foundation and has higher construction precision.

The embodiment of the invention is realized by the following technical scheme: a foundation pit support system comprising the steps of:

A. Firstly, excavating a foundation pit in a construction area by using large mechanical equipment, wherein the circumferential dimension of the actual excavation of the foundation pit is 2-3m larger than the circumferential dimension specified in a drawing, after the foundation pit is excavated in place, trimming, compacting and leveling the foundation pit, then using a total station instrument and a precise level to fix and position the foundation pit bottom wall, using paint to draw lines in the fixed point and the positioning area, and drawing a projection area of a ring beam specified in the construction drawing on the foundation pit bottom wall;

B. uniformly positioning pile driving points of a plurality of positioning piles in a projection area of the ring beam on the bottom wall of the foundation pit by using a total station, driving pile holes at the pile points by using a pile driver, fixing the positioning piles in the pile holes, pouring cement mortar into the pile holes so as to fix the positioning piles, and using a precise level gauge to ensure the verticality of the positioning piles during the process;

C. After the cement mortar in the pile hole is hardened, a worker builds a first layer of ring beam template in a paint area of a drawing line, after the first layer of ring beam template is built, a total station and a precise level are used for measuring the position accuracy of the first layer of ring beam template, if the position deviation exists, the position is continuously corrected until the position of the first layer of ring beam template is correct, then a layer of plastic film is wrapped on all positioning piles, meanwhile, a reinforcing steel bar net is built in the first layer of ring beam template, finally, cement mortar is poured into the first layer of ring beam template, and after the cement mortar in the first layer of ring beam template is hardened, the first layer of ring beam template is removed;

D. Laying a layer of plastic film on the first layer of ring beam, at this time, taking the first layer of ring beam as a foundation, leaning a second layer of ring beam template against the first layer of ring beam, thereby building a second layer of ring beam template, building a reinforcing mesh in the second layer of ring beam template, then pouring cement mortar into the second layer of ring beam template, and after the cement mortar in the second layer of ring beam template is hardened, removing the second layer of ring beam template;

E. Then a plurality of small cranes are used for simultaneously pulling the second-layer ring beams to vertically move upwards along the positioning piles, when the second-layer ring beams move to a proper height, a plurality of prefabricated supporting beams are used for uniformly supporting the second-layer ring beams between the first-layer ring beams and the second-layer ring beams, and expansion bolts are used for fixedly connecting the supporting beams, the first-layer ring beams and the second-layer ring beams together;

F. Symmetrically and fixedly mounting expansion bolts on the surface between the first layer ring beam and the second layer ring beam, welding the expansion bolts between the two expansion bolts by using a reinforcing bar, paving a reinforcing bar net between the first layer ring beam and the second layer ring beam, welding the reinforcing bar net together with the reinforcing bar net, building a template between the first layer ring beam and the second layer ring beam, fixing the template, finally pouring cement mortar into the template, and hardening the cement mortar in the template between the first layer ring beam and the second layer ring beam;

G. The scaffold is built from bottom to top at the inner side and the outer side of the ring beam from the bottom of the foundation pit, a worker can construct a plurality of subsequent layers of ring beams on the scaffold, the third layer of ring beams and the plurality of subsequent layers of ring beams repeat the steps D to F, the number of the ring beams appearing in the steps D to F is based on the ring beam layer under construction and the ring beam layer under construction until the construction of the plurality of layers of ring beams is completed and the height required by construction drawings is reached;

H. Burying a plurality of layers of annular steel rings on the bottom wall of the foundation pit and on the outer side of the first layer of annular beam according to a construction drawing, uniformly positioning pile hole points of a plurality of steel pile casings on the bottom wall of the foundation pit and on the outer side of the first layer of annular beam by using a total station, wherein the pile hole points of the steel pile casings are 1-2m away from the outermost annular steel rings, piling pile holes at the pile points by using a pile driver, then placing the steel pile casings, exposing the steel pile casings out of the bottom wall of the foundation pit for 0.4-0.6m, and filling cement mortar until the cement mortar is hardened;

I. building a reinforcing mesh on the outer side of the first layer of ring beam, enabling the reinforcing mesh to cover the annular steel ring and the steel pile casing and be welded with each other, building a template on the outer side of the reinforcing mesh and fixing the template, then pouring cement mortar into the template to form a cement reinforcing ring, and removing the template on the outer side of the reinforcing steel after the cement mortar is hardened;

J. Welding solid steel balls at one end of each steel casing, which is exposed out of the bottom wall of the foundation pit, penetrating a plurality of anchor rods inserted into the bottom wall of the foundation pit on each solid steel ball, wherein the anchor rods are in divergent and crossed arrangement, supporting rods are arranged between each layer of ring beam and each solid steel ball, one end of each supporting rod is welded with each solid steel ball, the other end of each supporting rod is fixedly welded with a connecting lug, and the connecting lugs are fixedly connected with the ring beams by using expansion bolts;

K. All supporting beams and supporting rods of each layer are mutually and respectively fixed together in series through a plurality of steel ropes, and all solid steel balls are also fixed together in series through a plurality of steel ropes;

m, connecting a fixing cap on the top of the positioning pile in a threaded manner, abutting the fixing cap on the top ring beam, and simultaneously using an expansion bolt to penetrate through the fixing cap to fix the fixing cap and the top ring beam together;

And N, removing all the remaining templates, removing all the scaffolds, pouring dregs between the ring beam and the side wall of the foundation pit by using a transport vehicle, compacting by using a road roller, and finally completing construction.

Further, the positioning pile comprises a plurality of guide posts, and the guide posts are mutually in threaded splicing together.

Further, the annular steel ring is provided with three circles and is pointed cone-shaped towards one side in the foundation pit bottom wall, and the height of the annular steel ring is gradually reduced towards one side close to the first layer ring beam.

Further, the steel pile casing is fixedly welded with a plurality of fins along the circumferential direction, the fins are arranged in a chamfer angle towards one side in the bottom wall of the foundation pit, and a plurality of grouting holes are formed in the circumferential wall of the steel pile casing.

Further, each layer of ring beam is uniformly prefabricated with a hook hole for hooking a hook of a small crane along the circumferential direction.

Further, clamping grooves for clamping the ring beams are prefabricated at two ends of the supporting beams.

The technical scheme of the embodiment of the invention has at least the following advantages and beneficial effects:

1. According to the construction method, the second layer ring beam and a plurality of layers of ring beams on the second layer ring beam can be referenced by taking the first layer ring beam as a reference, a template is built, cement mortar is poured into the template for construction, errors of each layer of ring beam can be smaller, meanwhile, the ring beam is pulled by a plurality of small cranes to ascend along the positioning piles, the positioning piles can play a role of guiding, the ring beam is prevented from being deviated along the vertical direction, a total station and a precise level are not used for scribing each layer, manpower is saved, a plastic film can play a role of separating the ring beams needing to be lifted, the accumulated adjustment of each layer of ring beam is lower, the construction quality is higher, the whole construction precision is higher, the positioning piles are arranged into a mode of mutually threaded splicing of a plurality of guide posts, the positioning piles can be spliced according to the height of the foundation pit, the weight of the positioning piles is reduced, workers can conveniently construct the foundation pit, all support beams and support rods are mutually connected in series and fixed together through a plurality of steel ropes respectively, and all solid steel balls are simultaneously fixed together through a plurality of solid steel balls, the support shafts can be further connected in series and can be inserted into a foundation pit for supporting system to be further stable foundation pit, and a long-time foundation pit can be required to be further constructed after the foundation pit is supported, and a foundation is stably supported, and a foundation is stable can be stably supported for a long is required to be constructed.

2. According to the invention, the annular steel ring is provided with three circles and is pointed towards one side in the bottom wall of the foundation pit, and is provided with three circles, so that the stability is better, the effect of blocking water penetration is achieved, the annular steel ring also has better connection strength, meanwhile, the cement reinforcing ring can be better integrated with the foundation, the strength of the foundation pit is improved, and the pointed cone of the annular steel ring is convenient for workers to embed the annular steel ring into the foundation by using construction equipment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a partial cross-sectional view of a foundation pit support system of the present invention during construction;

FIG. 2 is an enlarged view of portion A of FIG. 1 in accordance with the present invention;

FIG. 3 is an enlarged view of portion B of FIG. 1 in accordance with the present invention;

FIG. 4 is a schematic view showing the structure of the present invention for dumping dregs;

FIG. 5 is a schematic view of the overall structure of the foundation pit support system provided by the present invention;

FIG. 6 is an enlarged view of portion C of FIG. 5 in accordance with the present invention;

Fig. 7 is a schematic structural view of the slag soil poured into the gap between the ring beam and the side wall of the foundation pit and flattened.

Icon: the steel pile comprises the following components of a first layer of ring beams, a second layer of ring beams, 21-supporting beams, 211-clamping grooves, 22-cement reinforcing rings, 3-positioning piles, 31-guiding columns, 32-fixing caps, 4-reinforcing steel meshes, 41-cement mortar, 42-templates, 421-counter-pulling screws, 5-expansion bolts, 51-reinforcing steel bars, 6-small cranes, 61-hooking holes, 7-annular steel rings, 71-steel pile casings, 711-fins, 712-grouting holes, 72-solid steel balls, 721-anchor rods, 73-supporting rods, 74-connecting lugs, 74-steel ropes, 8-plastic films, 9-scaffolds and 91-dregs.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Examples

The present invention is further described below with reference to specific embodiments, and with reference to fig. 1-7, and is a foundation pit support system, comprising the steps of:

A. Firstly, excavating a foundation pit in a construction area by using equipment such as an excavator, wherein the circumferential dimension of the actual excavation of the foundation pit is 2-3m larger than the circumferential dimension specified in a drawing, after the foundation pit is excavated in place, trimming, compacting and leveling the foundation pit by using instruments such as a bulldozer, a road roller and the like, then fixing and positioning the foundation pit bottom wall by using a total station instrument and a precise level, drawing lines in the fixing and positioning areas by using paint, and drawing a projection area of a ring beam specified in the construction drawing on the foundation pit bottom wall;

B. Uniformly positioning pile driving points of a plurality of positioning piles 3 in a projection area of the ring beam on the bottom wall of the foundation pit by using a total station, wherein in actual implementation, the gap between each positioning pile 3 is generally 2m-4m, so that the positioning piles 3 can play a good role in subsequent positioning, then pile driving holes are formed in the pile points by using a pile driver, the depth of each pile hole is generally 5m-10m, the positioning piles 3 are fixed in the pile holes, cement mortar 41 is poured into the pile holes, and therefore the positioning piles 3 are fixed, and during the process, the positioning piles 3 are continuously measured and corrected by using a precise level gauge, so that the verticality of the positioning piles 3 is ensured;

C. After the cement mortar 41 in the pile hole is hardened, a worker builds a first layer of ring beam template in a paint area of a painted line, after the first layer of ring beam template is built, a total station and a precision level are used for measuring the position accuracy of the first layer of ring beam template, if the position deviation exists, the position is continuously corrected until the position of the first layer of ring beam template is correct, then a layer of plastic film 8 is wrapped on all positioning piles 3, meanwhile, a reinforcing steel bar net 4 is built in the first layer of ring beam template, finally cement mortar 41 is poured into the first layer of ring beam template, and after the cement mortar 41 in the first layer of ring beam template is hardened, the first layer of ring beam template is detached;

D. Laying a layer of plastic film 8 on the first layer of ring beam 1, at this time, based on the first layer of ring beam 1, leaning a second layer of ring beam template against the first layer of ring beam 1, thereby building a second layer of ring beam template, building a reinforcing steel bar net 4 in the second layer of ring beam template, then pouring cement mortar 41 into the second layer of ring beam template, and detaching the second layer of ring beam template after the cement mortar 41 in the second layer of ring beam template is hardened;

E. Then a plurality of small cranes 6 are used for simultaneously pulling the second-layer ring beam 2 to vertically move upwards along the positioning piles 3, when the second-layer ring beam 2 moves to a proper height, a plurality of prefabricated support beams 21 are used for uniformly supporting the second-layer ring beam 2 between the first-layer ring beam 1 and the second-layer ring beam 2, clamping grooves 211 for clamping the ring beams are prefabricated at two ends of the support beams 21 so as to clamp the ring beams, and the support beams 21, the first-layer ring beam 1 and the second-layer ring beam 2 are fixedly connected together by using expansion bolts 5;

F. The expansion bolts 5 are symmetrically and fixedly arranged on the surface between the first layer ring beam 1 and the second layer ring beam 2, the steel bar rods 51 are welded between the two expansion bolts 5, meanwhile, the steel bar nets 4 are paved between the first layer ring beam 1 and the second layer ring beam 2, then the steel bar rods 51 and the steel bar nets 4 are welded together, so that the integral strength between the ring beams can be improved, the formwork 42 is built between the first layer ring beam 1 and the second layer ring beam 2, the formwork 42 is fixed by the counter-pulling screws 421, cement mortar 41 is finally poured into the formwork 42, and the cement mortar 41 in the formwork 42 between the first layer ring beam 1 and the second layer ring beam 2 is hardened;

G. The scaffold 9 is built from bottom to top at the inner side and the outer side of the ring beam from the bottom of the foundation pit, a worker can construct a plurality of subsequent ring beams on the scaffold 9, the third ring beam and the plurality of subsequent ring beams repeat the steps D to F, the number of the ring beams appearing in the steps D to F is based on the ring beam layer being constructed and the ring beam layer below the ring beam layer being constructed until the construction of the plurality of ring beams is completed and the height required by a construction drawing is reached;

H. According to the construction drawing, a plurality of layers of annular steel rings 7 are buried on the bottom wall of a foundation pit and positioned on the outer side of a first layer of ring beam 1, in the implementation, the annular steel rings 7 are made of stainless steel materials, the annular steel rings 7 are formed by splicing and welding a plurality of arc-shaped steel sheets, meanwhile, pile hole points of a plurality of steel pile casings 71 are uniformly positioned on the bottom wall of the foundation pit and positioned on the outer side of the first layer of ring beam 1 by using a total station, the steel pile casings 71 are also made of stainless steel materials, the distance between the pile hole points of the steel pile casings 71 and the outermost annular steel rings 7 is 1-2m, pile holes are drilled at the pile points by using a pile driver, then the steel pile casings 71 are put in, the steel pile casings 71 are exposed out of the bottom wall of the foundation pit by 0.4-0.6m, cement mortar 41 is poured, and cement mortar 41 is waited for hardening;

I. Building a reinforcing steel bar net 4 on the outer side of the first layer ring beam 1, enabling the reinforcing steel bar net 4 to cover the annular steel ring 7 and the steel pile casing 71 and mutually welding, building a template 42 on the outer side of the reinforcing steel bar net 4 and fixing, then pouring cement mortar 41 to form a cement reinforcing ring 22, and removing the template 42 on the outer side of the reinforcing steel bar after the cement mortar 41 is hardened;

J. The solid steel balls 72 are welded at one end of each steel pile casing 71 exposing the bottom wall of the foundation pit, the solid steel balls 72 are also made of stainless steel materials, antirust paint is brushed on the surfaces of the solid steel balls 72, meanwhile, a plurality of anchor rods 721 inserted into the bottom wall of the foundation pit are arranged on each solid steel ball 72 in a penetrating mode, the anchor rods 721 are made of stainless steel materials, the anchor rods 721 are arranged in a divergent and crossed mode, a supporting rod 73 is arranged between each layer of ring beam and each solid steel ball 72, one end of the supporting rod 73 is welded with the solid steel ball 72, a connecting lug 74 is fixedly welded at the other end of the supporting rod 73, and the connecting lug 74 is fixedly connected with the ring beam through an expansion bolt 5;

K. All supporting beams 21 and supporting rods 73 of each layer are mutually and serially fixed together through a plurality of steel ropes 74, the steel ropes 74 are made of stainless steel, the surfaces of the steel ropes 74 are painted with antirust paint, and all solid steel balls 72 are serially fixed together through a plurality of steel ropes 74;

M, connecting a fixing cap 32 on the top of the positioning pile 3 in a threaded manner, abutting the fixing cap 32 on the top ring beam, and simultaneously using an expansion bolt 5 to penetrate through the fixing cap 32 to fix the fixing cap 32 and the top ring beam together;

And N, removing all the remaining templates 42, removing all the scaffolds 9, pouring dregs 91 between the ring beam and the side wall of the foundation pit by using a plurality of transport vehicles, compacting by using a road roller, and finally completing the construction.

The positioning pile 3 comprises a plurality of guide posts 31, the guide posts 31 are mutually connected together in a threaded manner, the annular steel rings 7 are buried into three circles and face one side in the bottom wall of the foundation pit in a pointed cone shape, in the implementation, the gap between the adjacent annular steel rings 7 is 0.2m-0.4m, the height of the annular steel rings 7 is gradually reduced towards one side close to the first layer of annular beam 1, the steel pile 71 is fixedly welded with a plurality of fins 711 along the circumferential direction, the fins 711 can increase the stability and strength of the steel pile 71, the fins 711 face one side in the bottom wall of the foundation pit and are arranged in a bevelled manner, the steel pile 71 can be conveniently inserted into the bottom wall of the foundation pit, and for a plurality of grouting holes 712 formed in the circumferential wall of the steel pile 71, after grouting the cement mortar 41 into the steel pile 71, the cement mortar 41 flows out of the grouting holes 712, and the cement mortar 41 outside the steel pile 71 can form a whole, so that the connectivity between the steel pile 71 and the foundation is improved, and the whole strength is improved, and the whole ring beam is uniformly provided with a plurality of hooks 6 in the circumferential direction for the small hooks (the crane is not shown in the small hook 6) for the crane; by adopting the foundation pit supporting system, the integral construction precision of the foundation pit support can be improved, the accumulated adjustment after each layer of ring beam construction is lower, and the construction quality is higher; the cement reinforcing ring 22, the solid steel balls 72, the steel casing 71, the supporting rods 73 and the anchor rods 721 are adopted for construction and reinforcement, so that the integral strength of the foundation pit support can be further improved, the foundation pit can be stably supported, and meanwhile, the foundation and the building can be stably supported.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a foundation ditch braced system which characterized in that: the method comprises the following steps:

B. Uniformly positioning pile driving points of a plurality of positioning piles (3) in a projection area of the ring beam on the bottom wall of the foundation pit by using a total station, driving pile holes at the pile points by using a pile driver, fixing the positioning piles (3) in the pile holes, pouring cement mortar (41) into the pile holes so as to fix the positioning piles (3), and using a precise level gauge to ensure the verticality of the positioning piles (3) during the process;

C. After the cement mortar (41) in the pile hole is hardened, a worker builds a first layer of ring beam template in a paint area of a painted line, after the first layer of ring beam template is built, a total station and a precision level are used for measuring the position accuracy of the first layer of ring beam template, if the position deviation exists, the position is continuously corrected until the position of the first layer of ring beam template is correct, then a layer of plastic film (8) is wrapped on all positioning piles (3), meanwhile, a reinforcing mesh (4) is built in the first layer of ring beam template, finally cement mortar (41) is poured into the first layer of ring beam template, and after the cement mortar (41) in the first layer of ring beam template is hardened, the first layer of ring beam template is removed;

D. Laying a layer of plastic film (8) on the first layer of ring beam (1), at this time, taking the first layer of ring beam (1) as a basis, leaning a second layer of ring beam template against the first layer of ring beam (1) so as to build a second layer of ring beam template, building a reinforcing mesh (4) in the second layer of ring beam template, then pouring cement mortar (41) into the second layer of ring beam template, and removing the second layer of ring beam template after the cement mortar (41) in the second layer of ring beam template is hardened;

E. Then a plurality of small cranes (6) are used for simultaneously pulling the second-layer ring beam (2) to vertically move upwards along the positioning piles (3), when the second-layer ring beam (2) moves to a proper height, a plurality of prefabricated support beams (21) are used for uniformly supporting the second-layer ring beam (2) between the first-layer ring beam (1) and the second-layer ring beam, and expansion bolts (5) are used for fixedly connecting the support beams (21), the first-layer ring beam (1) and the second-layer ring beam (2) together;

F. The method comprises the steps of symmetrically and fixedly mounting expansion bolts (5) on the surface between a first layer of ring beam (1) and a second layer of ring beam (2), welding between the two expansion bolts (5) by using reinforcing rods (51), paving a reinforcing mesh (4) between the first layer of ring beam (1) and the second layer of ring beam (2), welding the reinforcing rods (51) and the reinforcing mesh (4) together, building a template (42) between the first layer of ring beam (1) and the second layer of ring beam (2), fixing the template (42), finally pouring cement mortar (41) into the template (42), and hardening the cement mortar (41) in the template (42) between the first layer of ring beam (1) and the second layer of ring beam (2);

G. The scaffold (9) is built from bottom to top at the inner side and the outer side of the ring beam from the bottom wall of the foundation pit, a worker can construct a plurality of subsequent ring beams on the scaffold (9), the third ring beam and the plurality of subsequent ring beams are repeatedly subjected to the steps D to F, the number of the ring beams appearing in the steps D to F is based on the ring beam layer under construction and the ring beam layer under construction until the construction of the plurality of ring beams is completed, and the height required by a construction drawing is reached;

H. Burying a plurality of layers of annular steel rings (7) on the bottom wall of the foundation pit and outside the first layer of annular beams (1) according to a construction drawing, uniformly positioning pile hole points of a plurality of steel pile casings (71) on the bottom wall of the foundation pit and outside the first layer of annular beams (1) by using a total station, piling pile holes on the pile points by using a pile driver after the pile hole points of the steel pile casings (71) are 1-2m away from the outermost annular steel rings (7), putting the steel pile casings (71) into the pile holes, exposing the steel pile casings (71) outside the bottom wall of the foundation pit by 0.4-0.6m, and filling cement mortar (41) until the cement mortar (41) is hardened;

I. building a reinforcing mesh (4) on the outer side of the first layer ring beam (1), enabling the reinforcing mesh (4) to cover the annular steel ring (7) and the steel pile casing (71) and mutually weld, building a template (42) on the outer side of the reinforcing mesh (4) and fixing, then pouring cement mortar (41) to form a cement reinforcing ring (22), and removing the template (42) on the outer side of the reinforcing steel after the cement mortar (41) is hardened;

J. Welding solid steel balls (72) at one end of each steel pile casing (71) exposed out of the bottom wall of the foundation pit, simultaneously penetrating a plurality of anchor rods (721) inserted into the bottom wall of the foundation pit on each solid steel ball (72), wherein the anchor rods (721) are divergently and alternately arranged, supporting rods (73) are arranged between each layer of ring beam and each solid steel ball (72), one end of each supporting rod (73) is welded with each solid steel ball (72), the other end of each supporting rod is fixedly welded with a connecting lug (74), and the connecting lugs (74) are fixedly connected with the ring beams by using expansion bolts (5);

K. All supporting beams (21) and supporting rods (73) of each layer are mutually and respectively fixed together in series through a plurality of steel ropes (74), and all solid steel balls (72) are also fixed together in series through a plurality of steel ropes (74);

M, connecting a fixing cap (32) on the top of the positioning pile (3) in a threaded manner, abutting the fixing cap (32) on the top ring beam, and simultaneously using an expansion bolt (5) to penetrate through the fixing cap (32) to fix the fixing cap (32) and the top ring beam together;

and N, removing all the remaining templates (42), removing all the scaffolds (9), pouring dregs (91) between the ring beam and the side wall of the foundation pit by using a transport vehicle, compacting by using a road roller, and finally completing construction.

2. The foundation pit support system of claim 1, wherein: the positioning pile (3) comprises a plurality of guide posts (31), and the guide posts (31) are mutually in threaded splicing together.

3. The foundation pit support system of claim 1, wherein: the annular steel ring (7) is provided with three circles and is pointed towards one side in the foundation pit bottom wall, and the height of the annular steel ring (7) towards one side close to the first layer ring beam (1) is gradually reduced.

4. The foundation pit support system of claim 1, wherein: the steel pile casing (71) is fixedly welded with a plurality of fins (711) along the circumferential direction, the fins (711) are arranged at a chamfer angle towards one side in the bottom wall of the foundation pit, and a plurality of grouting holes (712) are formed in the circumferential wall of the steel pile casing (71).

5. The foundation pit support system of claim 1, wherein: and each layer of ring beam is uniformly prefabricated with a hook hole (61) for hooking a hook of a small crane (6) along the circumferential direction.

6. The foundation pit support system of claim 1, wherein: clamping grooves (211) for clamping the ring beam are prefabricated at two ends of the supporting beam (21).