Construction method of cover-excavation deep foundation pit support system

Abstract

The present application relates to a kind of construction methods of cover excavation deep foundation pit support system, including steps: fender pile and steel column construction, foundation pit excavation and support construction, cover plate construction, excavation construction, bottom plate construction, cover plate removal.The beneficial effects of the present application are: using fender pile net spraying concrete support structure and fender pile and steel enclosure purlin fast connection system, simple operation, can be local material, improve the strength of support structure and on-site construction efficiency;Through the construction of steel column accurate insertion auxiliary device, the precision of steel column insertion is guaranteed, the tediousness of manual adjustment in traditional method is reduced, manpower is saved, and construction efficiency is improved;Using steel column support type reinforced concrete cover plate formwork system and reinforced concrete cover plate steel column setting corbel bracket reinforcement structure for construction, the stability of formwork structure is improved, and reinforcement can be carried out for special conditions, to ensure the smooth progress of construction process and the safety of lower personnel.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of underground engineering, and particularly relates to a construction method of a cover-excavation deep foundation pit supporting system. BACKGROUND

[0002] With the continuous expansion of the city scale, the land resources in the city center are increasingly scarce, and the development of underground space has become an inevitable trend of city development. In the bustling downtown area, it is difficult to meet the design and construction requirements by using the conventional sequential method to construct large underground space projects due to the super-large and super-deep foundation pit, the extremely complex surrounding environment, the harsh environmental protection requirements, the great difficulty in traffic relief, and the very complicated pipeline relocation. Therefore, the cover-excavation method emerges as the times require. In the cover-excavation construction process, the cover plate needs to be constructed to reduce the impact on traffic, and therefore the requirements for the supporting and supporting structures are higher, and it is required to minimize the construction time, and the strength of the supporting structure and the construction efficiency need to be improved in the construction.

[0003] In view of this, in view of the deficiencies in the previous cover-excavation foundation pit construction, a new construction method of a cover-excavation deep foundation pit supporting system is urgently needed to improve the construction efficiency, improve the construction quality, and ensure the safety and reliability of the construction quality. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art, and to provide a construction method of a cover-excavation deep foundation pit supporting system.

[0005] The construction method of the cover-excavation deep foundation pit supporting system comprises the following steps:

[0006] Step one, construction of the retaining pile and the steel column: the retaining pile is constructed, the steel mesh fixing rib and the scissors block connecting rib are pre-buried on the main rib of the retaining pile, the column pile is constructed, and the steel column is accurately inserted into the auxiliary device to set the steel column;

[0007] Step two, foundation pit excavation and supporting construction: the foundation pit is excavated to the first concrete support bottom elevation; the corbel is constructed on the top of the retaining pile, the steel mesh is fixed at one end of the steel mesh fixing rib through the enlarged end plate, and then the sprayed concrete is constructed to form the concrete support;

[0008] Step three, cover plate construction: the cover plate steel bar is bound and supported by the steel column supporting type reinforced concrete cover plate formwork system to set the formwork, and the formwork is removed after pouring the cover plate;

[0009] Step four, excavation construction: excavate to the steel support bottom elevation, construct the steel surrounding purlin, and install and remove the structure of the steel support through the retaining pile and the steel surrounding purlin rapid connection system and the cover plate lower steel support to construct the steel support;

[0010] Step five, bottom plate construction: excavate to the pit bottom and complete the leveling, construct the cushion, waterproof and bottom plate, and remove the support to construct the main structure;

[0011] Step six, cover plate removal: the cover plate cutting and removal construction is carried out through the ground hanging reinforced concrete plate cutting system.

[0012] Preferably, in step one: the steel column precise insertion auxiliary device includes a base, a vertical bracket, a guide ring, an intermediate support, a diagonal support and a horizontal bracket, the base is fixed to the ground, and the assembly method of the steel column precise insertion auxiliary device is to fix the vertical bracket on the base, set the intermediate support in the middle position of the vertical bracket, fix one end of the diagonal support on the vertical bracket, and fix the other end on the intermediate support. The horizontal bracket connects the vertical brackets on both sides at the bottom and upper ends of the vertical bracket, and the guide ring is set in a rectangular frame composed of the vertical bracket and the horizontal bracket, and then the steel column is installed.

[0013] Preferably, in step three: the steel column supported reinforced concrete cover slab formwork system includes a crown beam, column piles, steel columns, formwork, supporting steel, steel fixings and steel hoops, the formwork is arranged at the bottom and both sides of the cover slab, the steel fixings are fixed to the sides of the crown beam by fixing nails, the steel hoops are arranged on the steel columns, the supporting steel slab is arranged at the bottom of the formwork, one end is fixed to the steel column by the steel hoop, and the other end is fixed to the steel fixings, the corbel pads are arranged on both sides of the steel column at the bottom of the supporting steel, the corbel bracket is fixed to the corbel pads, and then the cover slab concrete is poured.

[0014] Preferably, in step 4: the quick connection system between the guardrail pile and the steel guardrail purlin includes a scissor block, a steel guardrail purlin, a reinforcing rigid rib plate and a scissor block connecting rib, the reinforcing rigid rib plate is arranged on the steel guardrail purlin, the scissor block is connected to the side of the steel guardrail purlin, and the scissor block is connected to the guardrail pile through the scissor block connecting rib;

[0015] The steel support installation and dismantling structure under the cover plate includes concrete support, embedded vertical connecting ribs, embedded connecting parts, connecting reinforcement ribs, connecting top plate, triangular bracket, connecting joint, steel support, steel lifting rope and lifting ring.

[0016] Preferably, in step four: when constructing the steel support, pre-embedded vertical connecting bars are embedded in the concrete support, pre-embedded connecting pieces are set on the guard piles, the connecting reinforcement bars are connected to fix the pre-embedded connecting pieces, the connecting top plate is set on the bottom of the steel purlin and fixed on the pre-embedded connecting pieces, the triangular bracket is set on the connecting top plate, the connecting joint is set on the triangular bracket, and the steel purlin and the steel support are connected, the lifting ring is fixed on the pre-embedded vertical connecting bars, one end of the steel lifting rope is fixed on the lifting ring, and the other end lifts the steel support.

[0017] Preferably, in step four: the ground hanging reinforced concrete slab cutting system includes reinforcing diagonal rods, tracks, pulleys, steel frame pads, vertical rods, horizontal rods, movable lifting rings, hanging rods, cutting equipment and connecting rods, which are fixed to the ground through tracks, the pulleys are arranged at the bottom of the steel frame pads, the vertical rods are fixed on the steel frame pads, the horizontal rods connect the vertical rods on both sides, the reinforcing diagonal rods connect the longitudinal vertical rods, the movable lifting rings are arranged on the horizontal rods, and the cutting equipment is fixed under the movable lifting rings through the hanging rods to perform cover plate cutting and removal construction.

[0018] A deep foundation pit support system is obtained by any of the above methods.

[0019] The beneficial effects of the present invention are:

[0020] 1) The use of retaining pile mesh sprayed concrete support structure and retaining pile and steel purlin quick connection system is simple to operate and can use local materials, thereby improving the strength of the support structure and on-site construction efficiency.

[0021] 2) The construction is carried out by using auxiliary devices for precise insertion of steel columns, which ensures the accuracy of steel column insertion, reduces the tedious manual adjustment in traditional methods, saves manpower and improves construction efficiency.

[0022] 3) The steel column supported reinforced concrete cover slab formwork system and the reinforced concrete cover slab steel column are set with a corbel bracket reinforcement structure for construction, which improves the stability of the formwork structure. At the same time, reinforcement can be carried out according to special circumstances, ensuring the smooth progress of the construction process and the safety of the personnel below.

[0023] 4) The installation and dismantling technology of steel support under the cover plate is used for construction, which has reliable connection and stable structure. The lifting of the lifting rope can ensure better safety during the dismantling process.

[0024] 5) The construction is carried out by cutting out the reinforced concrete slab while hanging it from the ground, which simplifies the installation, improves the construction efficiency and shortens the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the retaining pile mesh sprayed concrete support structure;

[0026] Figure 2 This is a front view of the structure of the auxiliary device for precise insertion of steel columns;

[0027] Figure 3 This is a top view of the structure of the auxiliary device for precise insertion of steel columns;

[0028] Figure 4 This is a schematic diagram of the steel column supported reinforced concrete cover slab formwork system and the corbel bracket reinforcement structure;

[0029] Figure 5This is a schematic diagram of the quick connection system between the retaining piles and the steel purlins;

[0030] Figure 6 This is a schematic diagram of the installation and removal structure of the steel support under the cover plate;

[0031] Figure 7 This is the front view of the system structure of the ground suspended reinforced concrete slab cut out;

[0032] Figure 8 This is a side view of the system structure of the ground-suspended reinforced concrete slab cut out;

[0033] Figure 9 yes Figure 7 Middle AA section view.

[0034] In the figure: 1-main body side wall, 2-guard pile, 3-guard pile main reinforcement, 4-steel mesh fixing reinforcement, 5-enlarged end plate, 6-steel mesh, 7-sprayed concrete, 8-ground, 9-base, 10-vertical support, 11-guide ring, 12-intermediate support, 13-diagonal support, 14-transverse support, 15-corbel bracket, 16-crown beam, 17-column pile, 18-steel column, 19-cover plate, 20-formwork, 21-support steel, 22-steel fixing parts, 23-steel hoop, 24-corbel pad, 25-scissor block, 2 6-Steel purlin, 27-Reinforced rigid ribs, 28-Scissor block connecting bars, 29-Concrete support, 30-Embedded vertical connecting bars, 31-Cover plate reinforcement, 32-Embedded connectors, 33-Connecting reinforcement bars, 34-Connecting top plate, 35-Triangular bracket, 36-Connecting movable head, 37-Steel support, 38-Steel lifting rope, 39-Lifting ring, 40-Reinforced diagonal rod, 41-Track, 42-Pulley, 43-Steel frame pad, 44-Vertical rod, 45-Horizontal rod, 46-Moving lifting ring, 47-Lifting rod, 48-Cutting equipment, 49-Connecting rod. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the following examples. The following examples are provided only to facilitate understanding of the present invention. It should be noted that, without departing from the principles of the present invention, it is possible for a person skilled in the art to make various modifications to the present invention, and such improvements and modifications fall within the scope of the claims of the present invention.

[0036] Example 1

[0037] As an embodiment, a deep foundation pit support system and construction method includes the following steps:

[0038] Step 1: Construction preparation: Carry out on-site traffic control, close the construction area, allow machinery and equipment to enter the site, and inspect and accept the construction materials entering the site.

[0039] Construction of retaining piles: The retaining piles 2 are constructed one by one. When constructing the retaining piles 2, the steel mesh fixing bars 4 and the scissor block connecting bars 28 are pre-embedded on the main bars 3 of the retaining piles.

[0040] Steel column construction: positioning and laying out and constructing column piles 17, assembling steel column precise insertion auxiliary device, the base 9 is fixed to the ground 8, the vertical bracket 10 is fixed on the base 9, the middle bracket 12 is set in the middle position of the vertical bracket 10, one end of the diagonal bracket 13 is fixed on the vertical bracket 10, and the other end is fixed on the middle bracket 12, the horizontal bracket 14 connects the vertical brackets 10 on both sides at the bottom and upper ends of the vertical bracket 10, the guide ring 11 is set in the rectangular frame formed by the vertical bracket 10 and the horizontal bracket 14, and then the steel column 18 is driven.

[0041] Step 2: Excavation of foundation pit: Use machinery and manual labor to excavate the foundation pit to the bottom elevation of the first concrete support 29.

[0042] Foundation pit support construction: construct the crown beam 16 on the top of the retaining pile 2, fix the enlarged end plate 5 to one end of the steel mesh fixing bar 4, fix the steel mesh 6 to the enlarged end plate 5, and then construct the sprayed concrete 7 to form the concrete support 29.

[0043] Step three, cover plate construction: tie the cover plate steel bars 31 and support the formwork 20 through the steel column supported reinforced concrete cover plate formwork system. The formwork 20 is set at the bottom and both sides of the cover plate 19. The steel fixing parts 22 are fixed to the side of the crown beam 16 by fixing nails. The steel clamp 23 is set on the steel column 18. The supporting steel 21 is set at the bottom of the formwork 20, one end is fixed to the steel column 18 through the steel clamp 23, and the other end is fixed to the steel fixing part 22. The corbel pad 24 is set on both sides of the steel column 18 at the bottom of the supporting steel 21, and the corbel bracket 15 is fixed on the corbel pad 24. Then pour the concrete and remove the formwork after the strength reaches the requirement.

[0044] Step 4, excavation construction: excavate layer by layer to the bottom of the steel support, construct the steel purlin 26, and use the quick connection system between the guardrail pile and the steel purlin and the steel support under the cover plate to install and dismantle the structural construction steel support 37; strengthen the connection through the scissors block 25, and then construct the steel support, the embedded vertical connecting reinforcement 30 is embedded in the concrete support 29, the embedded connecting piece 32 is set on the guardrail pile 2, the connecting reinforcement 33 fixes the embedded connecting piece 32, the connecting top plate 34 is set at the bottom of the steel purlin 26 and fixed on the embedded connecting piece 32, the triangular bracket 35 is set on the connecting top plate 34, the connecting active head 36 is set on the triangular bracket 35, and the steel purlin 26 and the steel support 37 are connected, the lifting ring 39 is fixed on the embedded vertical connecting reinforcement 30, one end of the steel lifting rope 38 is fixed on the lifting ring 39, and the other end lifts the steel support 37.

[0045] Step 5: Base plate construction: After the excavation is completed to the bottom of the pit and leveling is completed, and after timely inspection and approval, the cushion layer, waterproofing and base plate are quickly constructed, and the supports are removed to construct the main structure.

[0046] Step six, cover plate removal: install the ground hanging reinforced concrete slab cutting system, fixed to the ground 8 through the track 41, the pulley 42 is set at the bottom of the steel frame pad 43, the vertical rod 44 is fixed on the steel frame pad 43, the horizontal rod 45 connects the vertical rods 44 on both sides, the reinforcing diagonal rod 40 connects the longitudinal vertical rods 44, the movable lifting ring 46 is set on the horizontal rod 45, and the cutting equipment 48 is fixed on the movable lifting ring 46 through the lifting rod 47 to perform cover plate cutting and removal construction.

[0047] After the construction is completed and inspected and accepted, the equipment and machinery will be dismantled and removed from the site.

[0048] Example 2

[0049] As another embodiment, the cover-excavation deep foundation pit support system obtained in embodiment 1 is composed of Figures 1 to 9 As shown, it includes the retaining pile mesh sprayed concrete support structure, the steel column supported reinforced concrete cover slab formwork system, the retaining pile and steel purlin quick connection system, the steel support installation and removal structure under the cover slab, and the ground hanging reinforced concrete slab cutting system;

[0050] The retaining pile mesh sprayed concrete support structure includes a retaining pile 2, a retaining pile main reinforcement 3, a steel mesh fixing reinforcement 4, an enlarged end plate 5, a steel mesh 6, and sprayed concrete 7. The retaining pile 2 is on one side of the main body side wall 1. The retaining pile main reinforcement 3 is arranged inside the retaining pile 2. The steel mesh fixing reinforcement 4 is arranged on the retaining pile main reinforcement 3. The enlarged end plate 5 is fixed to one end of the steel mesh fixing reinforcement 4. The steel mesh 6 is fixed to the enlarged end plate 5. The sprayed concrete 7 is on both sides of the steel mesh 6.

[0051] It also includes an auxiliary device for the precise insertion of steel columns, which includes a base 9, a vertical bracket 10, a guide ring 11, an intermediate support 12, an oblique support 13, and a horizontal bracket 14. The base 9 is fixed to the ground 8, the vertical bracket 10 is fixed on the base 9, the intermediate support 12 is arranged in the middle position of the vertical bracket 10, one end of the oblique support 13 is fixed on the vertical bracket 10, and the other end is fixed on the intermediate support 12, the horizontal bracket 14 connects the vertical brackets 10 on both sides at the bottom and upper ends of the vertical bracket 10, and the guide ring 11 is arranged in a rectangular frame formed by the vertical bracket 10 and the horizontal bracket 14.

[0052] It also includes a steel column supported reinforced concrete cover slab formwork system, which includes a crown beam 16, column piles 17, steel columns 18, formwork 20, supporting steel sections 21, steel section fixing parts 22, and steel clamps 23. The crown beam 16 is arranged on the retaining piles 2, the steel columns 18 are arranged on the column piles 17, the formwork 20 is arranged at the bottom and both sides of the cover slab 19, the steel section fixing parts 22 are fixed to the side of the crown beam 16 by fixing nails, the steel clamps 23 are arranged on the steel columns 18, and the supporting steel sections 21 are arranged at the bottom of the formwork 20, one end of which is fixed to the steel column 18 by the steel clamp 23, and the other end is fixed to the steel section fixing parts 22.

[0053] It also includes a corbel bracket reinforcement structure set on the reinforced concrete cover plate steel column, and the corbel bracket reinforcement structure set on the reinforced concrete cover plate steel column includes a corbel bracket 15 and a corbel pad 24. The corbel pad 24 is set on both sides of the steel column 18 at the lower part of the supporting steel 21, and the corbel bracket 15 is fixed on the corbel pad 24.

[0054] As an improved specific implementation method, it also includes a quick connection system between guardrail piles and steel guardrail purlins, and the quick connection system between guardrail piles and steel guardrail purlins includes a scissor block 25, a reinforcing rigid rib plate 27, and a scissor block connecting rib 28. The reinforcing rigid rib plate 27 is arranged on the steel guardrail purlin 26, and the scissor block 25 is connected to the side of the steel guardrail purlin 26 and is connected to the guardrail pile 2 through the scissor block connecting rib 28.

[0055] The steel support installation and removal structure under the cover plate is also included, and the steel support installation and removal structure under the cover plate includes a concrete support 29, embedded vertical connecting ribs 30, embedded connecting pieces 32, connecting reinforcement ribs 33, a connecting top plate 34, a triangular bracket 35, a connecting flexible head 36, a steel support 37, a steel lifting rope 38, and a lifting ring 39. The embedded vertical connecting ribs 30 are embedded in the concrete support 29, the embedded connecting pieces 32 are arranged on the retaining piles 2, the connecting reinforcement ribs 33 fix the embedded connecting pieces 32, the connecting top plate 34 is arranged at the bottom of the steel purlin 26 and fixed on the embedded connecting pieces 32, the triangular bracket 35 is arranged on the connecting top plate 34, the connecting flexible head 36 is arranged on the triangular bracket 35, and connects the steel purlin 26 and the steel support 37, the lifting ring 39 is fixed on the embedded vertical connecting ribs 30, one end of the steel lifting rope 38 is fixed on the lifting ring 39, and the other end lifts the steel support 37.

[0056] It also includes a ground-suspended reinforced concrete slab cutting system, which includes a reinforcing diagonal rod 40, a track 41, a pulley 42, a steel frame pad 43, a vertical rod 44, a horizontal rod 45, a movable lifting ring 46, a hanging rod 47, a cutting device 48, and a connecting rod 49. The track 41 is fixed to the ground 8, the pulley 42 is arranged at the bottom of the steel frame pad 43, the vertical rod 44 is fixed on the steel frame pad 43, the horizontal rod 45 connects the vertical rods 44 on both sides, the reinforcing diagonal rod 40 connects the longitudinal vertical rod 44, the movable lifting ring 46 is arranged on the horizontal rod 45, and the cutting device 48 is fixed below the movable lifting ring 46 through the connecting rod 49 and the hanging rod 47.

Claims

1. A construction method for a deep foundation pit support system, characterized in that: The following steps are involved: Step 1: Construction of retaining piles and steel columns: Construction of retaining piles (2), pre-embedding of steel mesh fixing bars (4) and scissor block connecting bars (28) on the retaining pile main bars (3); construction of column piles (17), and installation of steel columns (18) using a steel column precision insertion auxiliary device; Step 2: Excavation of foundation pit and construction of support: excavation of foundation pit to the bottom elevation of the first concrete support (29); construction of crown beam (16) on the top of retaining pile (2), fixing steel mesh (6) at one end of steel mesh fixing bar (4) through enlarged end plate (5), and then construction of sprayed concrete (7) to form concrete support (29); Step 3, cover plate construction: tie the cover plate reinforcement (31) and support the formwork (20) through the steel column supported reinforced concrete cover plate formwork system, cast the cover plate (19) and then remove the formwork; The steel column supported reinforced concrete cover plate formwork system comprises a crown beam (16), a column pile (17), a steel column (18), a template (20), a supporting steel (21), a steel fixing piece (22) and a steel hoop (23), wherein the template (20) is arranged at the bottom and both sides of the cover plate (19), the steel fixing piece (22) is fixed to the side of the crown beam (16) by fixing nails, the steel hoop (23) is arranged on the steel column (18), the supporting steel (21) is arranged at the bottom of the template (20), one end is fixed to the steel column (18) by the steel hoop (23), and the other end is fixed to the steel fixing piece (22), the corbel pad (24) is arranged on both sides of the steel column (18) at the bottom of the supporting steel (21), the corbel bracket (15) is fixed on the corbel pad (24), and then the concrete of the cover plate (19) is poured; Step 4, excavation construction: excavate to the bottom elevation of the steel support (37), construct the steel purlin (26), and install and dismantle the structural construction steel support (37) through the quick connection system between the retaining piles and the steel purlin and the steel support under the cover plate; The quick connection system between the guard pile and the steel guard purlin comprises a scissor block (25), a steel guard purlin (26), a reinforcing rigid rib plate (27) and a scissor block connecting rib (28), wherein the reinforcing rigid rib plate (27) is arranged on the steel guard purlin (26), the scissor block (25) is connected to the side of the steel guard purlin (26), and the scissor block (25) is connected to the guard pile (2) via the scissor block connecting rib (28); The steel support installation and removal structure under the cover plate includes a concrete support (29), a pre-buried vertical connecting rib (30), a pre-buried connecting piece (32), a connecting reinforcing rib (33), a connecting top plate (34), a triangular bracket (35), a connecting joint (36), a steel support (37), a steel lifting rope (38) and a lifting ring (39); When constructing the steel support (37), a pre-embedded vertical connecting rib (30) is pre-embedded in the concrete support (29), a pre-embedded connecting piece (32) is set on the retaining pile (2), the connecting reinforcement rib (33) is fixed to the pre-embedded connecting piece (32), a connecting top plate (34) is set at the bottom of the steel purlin (26) and fixed on the pre-embedded connecting piece (32), a triangular bracket (35) is set on the connecting top plate (34), a connecting active head (36) is set on the triangular bracket (35) and connects the steel purlin (26) and the steel support (37), a lifting ring (39) is fixed on the pre-embedded vertical connecting rib (30), one end of a steel lifting rope (38) is fixed on the lifting ring (39), and the other end lifts the steel support (37); Step 5: Base plate construction: excavate to the bottom of the pit and complete the leveling, apply the cushion layer, waterproofing and base plate, and remove the support to construct the main structure; Step 6, cover plate removal: the cover plate (19) is cut and removed by using the ground hanging reinforced concrete plate cutting system.

2. The construction method of the cover-excavation deep foundation pit support system according to claim 1 is characterized in that: In step 1: the steel column precise insertion auxiliary device includes a base (9), a vertical bracket (10), a guide ring (11), an intermediate support (12), an oblique support (13) and a transverse support (14), the base (9) is fixed to the ground (8), and the assembly method of the steel column precise insertion auxiliary device is as follows: the vertical bracket (10) is fixed to the base (9), the intermediate support (12) is set in the middle position of the vertical bracket (10), one end of the oblique support (13) is fixed to the vertical bracket (10), and the other end is fixed to the intermediate support (12), the transverse support (14) connects the vertical brackets (10) on both sides at the bottom and top of the vertical bracket (10), the guide ring (11) is set in a rectangular frame composed of the vertical bracket (10) and the transverse bracket (14), and then the steel column (18) is set.

3. The construction method of the cover-excavation deep foundation pit support system according to claim 1 is characterized in that: In step 4, the ground hanging reinforced concrete slab cutting system includes a strengthening diagonal rod (40), a track (41), a pulley (42), a steel frame pad (43), a vertical rod (44), a horizontal rod (45), a mobile ring (46), a hanging rod (47), a cutting device (48) and a connecting rod (49), which are fixed to the ground (8) through the track (41), the pulley (42) is set at the bottom of the steel frame pad (43), the vertical rod (44) is fixed on the steel frame pad (43), the horizontal rod (45) connects the vertical rods (44) on both sides, the strengthening diagonal rod (40) connects the longitudinal vertical rod (44), the mobile ring (46) is set on the horizontal rod (45), and the cutting device (48) is fixed below the mobile ring (46) through the connecting rod (49) and the hanging rod (47) to perform the cover plate (19) cutting and removal construction.

4. Cover-excavation deep foundation pit support system, characterized by: Obtained by the method according to any one of claims 1 to 3.

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