Pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction method

Abstract

The present application relates to a kind of pile-plate-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction method, comprising the following steps: foundation pit retaining structure construction, pipeline both sides bored pile construction, middle static drill root planting pile construction, side static drill root planting pile construction, corbel, end plate construction, bailey beam erection, pipe joint sleeve hoop installation and suspension construction.The beneficial effects of the present application are: the contact strength between pipe sections is effectively improved by longitudinal anchor cable, thereby avoiding the leakage problem at pipe joint during suspension process, and the technical advantage is significant;The suspension system composed of double bailey truss beam, pipe joint sleeve hoop and pulley lifting can make the pipeline uniformly stressed and synchronously suspended and lifted, avoiding excessive deflection caused by uneven pipeline suspension, which can cause pipeline damage;Static drill root planting pile and transverse pad beam can be recycled and reused in later stage.

Description

TECHNICAL FIELD

[0001] The present application is suitable for the construction of pipeline bailey beam suspension protection, and relates to a pile-plate-cable reinforced large-span foundation pit deep-buried pipeline suspension protection method, which is particularly suitable for the construction of bailey beam suspension protection of pile-plate-cable reinforced large-span foundation pit deep-buried multi-section pipe, multi-section steel pipe and multi-section other types of reinforced concrete pipe with a span of more than 20 m and a buried depth of more than 5 m. BACKGROUND

[0002] With the development of super high buildings, the span and depth of foundation pits have increased significantly, and therefore, more and more large-span super deep foundation pit projects have emerged. In the process of excavation and support of large-span super deep foundation pits, the problem of underground pipelines cannot be avoided. When the underground pipelines are not deeply buried, there are some solutions in the current technology, such as CN104676110A and CN114016383A, which propose to use bailey truss for in-situ suspension protection; CN112359838A and CN213741089U respectively propose to use bridge truss similar to bailey beam and double-spliced channel steel for suspension; CN217030242U proposes a flexible pipeline suspension device mainly using anchoring system and suspension system; and CN113969583A proposes a suspension structure and method of "radiating at both ends and parallel at the middle" for high-voltage cable pipelines.

[0003] However, the above methods are mainly for shallow-buried pipelines and single-section pipelines. For multi-section pipelines with a span of more than 20 m and a buried depth of more than 5 m, the above existing technologies cannot solve the problem of contact and leakage between pipe sections, and excessive suspension disturbance will affect the normal use of the pipeline. Therefore, there is an urgent need for a construction method for large-span foundation pit deep-buried pipeline suspension protection that can ensure the normal use of the pipeline and prevent leakage between pipe sections. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a pile-plate-cable reinforced large-span foundation pit deep-buried pipeline suspension protection construction method.

[0005] The pile-plate-cable reinforced large-span foundation pit deep-buried pipeline suspension protection construction method comprises the following construction steps:

[0006] Step 1, foundation pit support structure construction: construct the support structure, and the depth of the support structure exceeds the deepest excavation line of the foundation pit;

[0007] Step 2, pipe two-side bored pile construction: construct bored piles on both sides of the pipeline;

[0008] Step three, construction of middle static drill root pile: the surface of the retaining structure is preliminarily excavated to form a preliminary excavation line, and then the middle static drill root pile is constructed, the top of the middle static drill root pile is flush with the preliminary excavation line;

[0009] Step four, construction of side static drill root pile: the foundation pit is excavated to the middle of the preliminary excavation line and the pipe buried depth line to form a secondary excavation line; two pairs of side static drill root piles are constructed synchronously, the top of the side static drill root pile is flush with the secondary excavation line;

[0010] Step five, construction of corbel and end plate: the foundation pit is excavated to the bottom of the pipe, and the corbel is constructed on the top of the bored pile; the local excavation line one is formed by locally excavating the soil in the pit directly below the completed corbel, the end plate is anchored between the bored piles to wrap the pipe, and a plurality of anchor ends are embedded in the end plate facing the side of the foundation pit;

[0011] Step six, erection of Bailey beam: the middle transverse cushion beam and the side transverse cushion beam are hoisted, and the Bailey truss beam is erected after adjusting the height of the side transverse cushion beam and the middle transverse cushion beam;

[0012] Step seven, installation of pipe joint sleeve and suspension construction: the local excavation line two is formed by locally excavating at the pipe joint, the rubber sealing ring is installed at the pipe joint, and then the pipe joint sleeve and the longitudinal anchor cable are installed; the suspension system is installed on the Bailey truss beam directly above the installed pipe joint sleeve, and the steel rope is connected and then the winch is slowly started to suspend.

[0013] As preferred, in step one: the retaining structure does not cut off the pipe, a safe static distance of 0.5-1.0 m is maintained between the retaining structure and the pipe, and no retaining structure is provided directly below the pipe section.

[0014] As preferred, in step two: the bored pile maintains a safe static distance of 2.0-3.0 m with the pipe; the diameter of the bored pile is greater than or equal to 1.0 m, the bottom depth of the bored pile exceeds the depth of the retaining structure, and the top depth of the bored pile exceeds the top of the buried pipe by 0.5-1.0 m.

[0015] As preferred, in step seven: the degree of pipe suspension is determined by measuring the pressure below the pipe, and when the pressure below the pipe is zero, it indicates that the pipe suspension is completed.

[0016] As preferred, in step seven: the pipe joint sleeve is formed by a pair of half-ring sleeves connected by a pair of pull bolts, the length of the pipe joint sleeve is consistent with the size of the pipeline diameter, and the diameter of the pipe joint sleeve is 1.1 times the diameter of the pipeline; the two side ends of the half-ring sleeve are provided with butt ears, and the butt ears are provided with pull holes; the outer side of the middle part of the half-ring sleeve is provided with a lifting shaft lateral connecting pulley; eight cable pulling ears are symmetrically arranged on the pipe joint sleeve, the cable pulling ears correspond to the four anchor ends on the end plate, the cable pulling ears are provided with pull holes, and the longitudinal anchor cable is anchored by bolt connection; after the pipeline suspension is completed, the middle transverse cushion beam and the side transverse cushion beam are removed, and the residual static drill root pile outside the exposed pit is removed and recycled, and at the same time, the foundation pit is continuously excavated, as the continuous excavation line continues to move downward, the residual static drill root pile gradually exposes outside the pit, and the residual static drill root pile outside the pit is gradually removed and recycled, and at the same time, the prefabricated baffle is gradually installed below the end plate.

[0017] As preferred, in step seven: the suspension system includes a pair of hoists, a plurality of pulleys and a pair of fixed ends, the steel rope is sent from the fixed end, passes through the pulleys on the pipe joint sleeve and the pulleys on the bailey truss beam in turn, and is connected to the hoist, then the hoist is started slowly, the degree of suspension of the pipeline is determined by measuring the pressure below the pipeline, and when the pressure below the pipeline is just zero, it is indicated that the suspension is completed.

[0018] A pile-plate-cable reinforced large-span foundation pit deep-buried pipeline suspension protection structure obtained according to any of the above methods.

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

[0020] 1) Compared with other large-span pipeline suspension protection technologies, the pile-plate-cable reinforced structure in the present application effectively improves the contact strength between pipe sections through longitudinal anchor cables, thereby avoiding the leakage problem at the pipe joint during suspension, and the technical advantage is significant.

[0021] 2) Compared with other large-span pipeline suspension protection technologies, the suspension system composed of the double bailey truss beams, the pipe joint sleeve and the pulley lifting in the present application can make the pipeline bear force uniformly and be lifted synchronously, thereby avoiding the phenomenon that the deflection is too large due to uneven pipeline suspension, causing pipeline damage, so the present application improves the suspension protection capability of the large-span foundation pit deep-buried pipeline, solves the problems of large suspension stability and large deflection of the large-span transverse pipeline in the prior art, and the technical advantage is significant.

[0022] 3) The static drill root pile and the transverse cushion beam in the present application can be recycled and reused in the later stage as the suspension construction develops, thereby saving materials and protecting the environment, so the present application also has certain economic and environmental benefits. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic view of a cross section of a foundation pit support structure construction;

[0024] Figure 2 is a cross-sectional view of the construction of the bored pile on both sides of the pipeline;

[0025] Figure 3 is a cross-sectional view of the preliminary excavation of the foundation pit and the construction of the static drilling root pile in the middle;

[0026] Figure 4 is a cross-sectional view of the re-excavation of the foundation pit and the construction of the static drilling root pile on the side;

[0027] Figure 5 is a cross-sectional view of the third excavation of the foundation pit and the local excavation;

[0028] Figure 6 is a cross-sectional view of the construction of the corbel and the end plate;

[0029] Figure 7 is a cross-sectional view of the erection of the Bailey beam;

[0030] Figure 8 is a plan view of the erection of the Bailey beam;

[0031] Figure 9 is a cross-sectional view of the local excavation at the pipe joint;

[0032] Figure 10 is a cross-sectional view of the pipe joint sleeve;

[0033] Figure 11 is a cross-sectional view of the installation of the pipe joint sleeve and the longitudinal anchor cable;

[0034] Figure 12 is a plan view of the installation of the pipe joint sleeve and the longitudinal anchor cable;

[0035] Figure 13 is a cross-sectional view of the construction of the pipeline suspension;

[0036] Figure 14 is a cross-sectional view of the construction of the pipeline suspension; Figure 13 is a cross-sectional view of the construction of the pipeline suspension;

[0037] Figure 15 is a cross-sectional view of the construction of the pipeline suspension; Figure 13 is a cross-sectional view of the construction of the pipeline suspension;

[0038] Figure 16 is a cross-sectional view of the construction of the pipeline suspension;

[0039] Figure 17 is a cross-sectional view of the construction of the pipeline suspension;

[0040] Figure 18 is a cross-sectional view of the construction of the pipeline suspension;

[0041] In the diagram: 1-Retaining structure; 2-Deepest excavation line; 3-Pipeline; 4-Drilled pile; 5-Central static drilled pile; 6-Surface; 7-Initial excavation line; 8-Side static drilled pile; 9-Secondary excavation line; 10-Cap beam; 11-End plate; 12-Local excavation line one; 13-Rubber sealing ring; 14-Anchoring end; 15-Central transverse support beam; 16-Side transverse support beam; 17-Bailey beam unit; 18-Bailey truss beam; 19-Transverse connecting beam; 20- Longitudinal connecting beam; 21-pipe joint; 22-second excavation line; 23-pipe joint sleeve; 24-semi-circular sleeve; 25-tie bolt; 26-butting lug; 27-pull hole; 28-pulley; 29-cable pull lug; 30-bolt; 31-longitudinal anchor cable; 32-winch; 33-fixed end; 34-steel rope; 35-residual static drilled pile; 36-precast baffle; 37-soil in the pit; 38-continued excavation line; 39-pit wall; 40-lifting shaft. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0043] Example 1

[0044] As one example, such as Figures 1 to 18 As shown, a method for suspending and protecting deep-buried pipelines in a large-span foundation pit using a pile-slab-cable system specifically includes the following steps:

[0045] Step 1: Construction of the foundation pit retaining structure: The retaining structure 1 adopts the form of reinforced cement-soil mixing piles to carry out water-stopping and retaining operations on the foundation pit. The depth of the retaining structure 1 exceeds the deepest excavation line 2 of the foundation pit; and the retaining structure 1 must not penetrate the deep buried pipeline 3 that runs through the foundation pit, and maintain a safe static distance of 0.5 to 1.0m from it. The retaining structure 1 will not be constructed directly below the cross section of the deep buried pipeline 3 in the foundation pit for the time being.

[0046] Step 2: Construction of bored piles on both sides of the pipeline: On both sides of the deep-buried pipeline 3 that crosses the foundation pit, a pair of bored piles 4 are constructed. The bored piles 4 and the pipeline 3 need to maintain a safe static distance of 2.0 to 3.0m. The diameter of the bored piles 4 should not be less than 1.0m. The bottom depth of the bored piles 4 exceeds the depth of the retaining structure 1, and the top depth of the bored piles 4 exceeds the top of the deep-buried pipeline 3 by 0.5 to 1.0m.

[0047] Step 3: Preliminary excavation of the foundation pit and construction of the central static drilled piles: Along the ground surface 6 enclosed by the retaining structure 1, the foundation pit is first preliminarily excavated to form the initial excavation line 7. Then, a pair of central static drilled piles 5 are constructed on both sides of the middle of the initial excavation line 7 and directly above the cross-section of the buried pipeline 3. The static distance between the central static drilled piles 5 and the pipeline 3 is 2.0 to 3.0 m, and its depth is more than 5.0 m below the buried pipeline 3, but cannot exceed the deepest excavation line 2 of the foundation pit. The top of the central static drilled piles 5 is consistent with the initial excavation line 7, and the diameter is 0.5 to 0.6 m.

[0048] Step 4: Re-excavation of the foundation pit and construction of lateral static drilled piles: After the construction of the central static drilled pile 5 is completed, the foundation pit is excavated again to form a secondary excavation line 9. The depth of the secondary excavation line 9 is approximately between the initial excavation line 7 and the burial depth line of the pipeline 3. Then, on the secondary excavation line 9, two pairs of lateral static drilled piles 8 are constructed simultaneously on both sides, between the central static drilled pile 5 and the bored pile 4, and directly above the cross-section of the deeply buried pipeline 3. The top of the lateral static drilled piles 8 is consistent with the secondary excavation line 9, and other geometric dimensions and positions are consistent with those of the central static drilled pile 5.

[0049] Step 5: Third Excavation of the Foundation Pit and Construction of the Crown Beam and End Plate: The third excavation of the foundation pit includes two steps. First, the excavation is carried out to the bottom of the pipe 3, and a pair of crown beams 10 are constructed on both sides of the bored pile 4. Then, a partial excavation is carried out directly below the completed crown beams 10 to form a partial excavation line 12, and then the cast-in-place end plate 11 is constructed. The end plate 11 is anchored on both sides to the bored pile 4 and runs through the middle of the pipe 3. Rubber sealing rings 13 are pre-installed between the pipe 3 and the end plate 11. The rubber sealing rings 13 can also be used as the inner formwork for the construction of the end plate 11. Four anchoring ends 14 are symmetrically pre-embedded on the side of the end plate 11 facing the foundation pit.

[0050] Step Six: Bailey Beam Erection: Specific construction details are as follows.

[0051] 6.1 Lifting of transverse support beams: Lift one transverse support beam 15 between a pair of central static drilled piles 5, and lift two transverse support beams 16 between two pairs of lateral static drilled piles 8, and adjust the height of the transverse support beams 16 and the transverse support beam 15.

[0052] 6.2 Longitudinal Bailey Beam Unit Lifting: Bailey beam units 17 are lifted between the cap beam 10 and the side transverse support beam 16, and between the side transverse support beam 16 and the central transverse support beam 15, respectively, to form two symmetrical parallel triangular Bailey truss beams 18; in addition, in order to increase the overall stiffness of the two Bailey truss beams 18, it is also necessary to install the transverse connecting beam 19 and the longitudinal connecting beam 20.

[0053] 6.3 Installation of transverse connecting beams: Multiple transverse connecting beams 19 are symmetrically arranged between the transverse sections of the double Bailey truss beams 18. The transverse connecting beams 19 are located in the middle of the Bailey beam unit 17, and the height of the transverse connecting beams 19 is half of that of the Bailey beam unit 17.

[0054] 6.4 Installation of longitudinal tie beams: Two longitudinal tie beams 20 are installed between the longitudinal isosceles points of the double Bailey truss beams 18. The height of the longitudinal tie beams 20 is three-quarters of the height of the Bailey beam element 17.

[0055] Step 7: Local excavation at pipe joints and installation of pipe joint clamps: The specific steps are as follows.

[0056] 7.1 Local excavation at pipe joint: Determine the location of the pipe joint 21 that crosses the foundation pit 3, and then conduct local excavation at the pipe joint 21 to form a second excavation line 22, so as to facilitate the installation of the pipe joint sleeve 23 later.

[0057] 7.2 Pipe Connection Coupling Fabrication: The pipe connection coupling 23 is formed by connecting a pair of semi-circular couplings 24 with tie bolts 25. The length of the pipe connection coupling 23 is the same as the diameter of the pipe 3, and the diameter of the pipe connection coupling 23 is 1.1 times the diameter of the pipe 3. The two ends of the semi-circular coupling 24 are provided with continuous connecting lugs 26, and the connecting lugs 26 are provided with pull holes 27. The middle outer side of the semi-circular coupling 24 is provided with a lifting shaft 40 for lateral connection of pulleys 28. At the corresponding positions of the four pre-embedded anchor ends 14 on the end plate 11, eight cable pull lugs 29 are symmetrically arranged on the pipe connection coupling 23. The cable pull lugs 29 are provided with pull holes 27, and the longitudinal anchor cables 31 are anchored by bolts 30.

[0058] 7.3 Pipe fitting installation: Before installing the pipe fitting 23, first pre-install a layer of rubber sealing ring 13 at the pipe joint 21, and then install the pipe fitting 23 on the rubber sealing ring 13.

[0059] 7.4 Longitudinal Anchor Cable Installation: Longitudinal anchor cables 31 are installed sequentially from both sides to the middle between the pipe joint sleeve 23 and the end plate 11, and between adjacent pipe joint sleeves 23, thus completing the plate-cable reinforcement structure of the pipe 3, which can ensure the contact strength between pipe sections of the pipe 3 and prevent leakage.

[0060] Step 8, Pipeline Suspension Construction: The specific construction process is as follows.

[0061] 8.1 Installation of fixed components: including winch 32, pulley 28 and fixed end 33. At the corresponding position directly above the installed pipe fitting 23, from one side to the other, install a pair of winches 32, multiple pairs of pulleys 28 and a pair of fixed ends 33 on the Bailey truss beam 18.

[0062] 8.2 Threading the steel rope and starting the suspension: Using the steel rope 34, start from the fixed end 33, pass through the pulley 28 on the pipe fitting sleeve 23 and the pulley 28 on the Bailey truss beam 18 in sequence, and connect to the winch 32. Then slowly start the winch 32. By measuring the pressure below the pipe 3, determine the degree of suspension of the pipe 3. When the pressure below the pipe 3 is exactly zero, it indicates that the suspension is complete.

[0063] Step 9: Remove the transverse support beams and exposed static drilled piles: After the pipeline 3 is suspended, gradually remove the middle transverse support beam 15 and the side transverse support beam 16, and then remove and recycle the exposed static drilled piles below the transverse support beams.

[0064] Step 10: Continue excavation of the foundation pit: Continue excavating the soil 37 in the pit from the bottom of the pipe 3 downwards. While continuing to excavate downwards along the excavation line 38, gradually recover the remaining static drilled piles 35, and gradually install the prefabricated baffles 36 directly below the end plate 11. The prefabricated baffles 36 are fixed between the drilled piles 4, thereby improving the support system of the foundation pit to prevent local soil collapse of the foundation pit wall 39 below the pipe 3.

[0065] Example 2

[0066] As another embodiment, such as Figures 1 to 17 As shown, according to the pile-slab-cable-reinforced deep-buried pipeline suspension protection method for large-span foundation pits given in Embodiment 1, a Bailey beam suspension protection structure for deep-buried pipelines in pile-slab-cable-reinforced deep-span foundation pits includes:

[0067] The structure consists of a retaining structure 1, a pipe 3, statically drilled piles, a Bailey truss beam 18, pipe couplings 23, and a suspension system. The retaining structure 1 is located in the soil outside the excavation pit. A pair of bored piles 4 are symmetrically arranged on both sides of the end of the pipe 3 inside the excavation pit. The diameter of the bored piles 4 is greater than or equal to 1.0m. The bottom depth of the bored piles 4 exceeds the depth of the retaining structure 1, and the top depth of the bored piles 4 exceeds the top of the pipe 3 by 0.5 to 1.0m. The depth of the statically drilled piles is more than 5.0m below the pipe 3, but the bottom of the statically drilled piles is higher than the deepest excavation line 2 of the excavation pit. The diameter of the statically drilled piles is 0.5 to 0.6m.

[0068] The statically drilled piles include a central statically drilled pile 5 and a lateral statically drilled pile 8. The central statically drilled pile 5 and the lateral statically drilled pile 8 are symmetrically arranged on both sides of the pipeline 3. The central statically drilled pile 5 is located in the center of the foundation pit, and the lateral statically drilled pile 8 is located between the central statically drilled pile 5 and the bored pile 4. The distances between the bored pile 4, the central statically drilled pile 5, and the lateral statically drilled pile 8 and the pipeline 3 are all 2.0 to 3.0 m, and the distances between the bored pile 4, the central statically drilled pile 5, and the lateral statically drilled pile 8 and the pipeline 3 are equal.

[0069] The top heights of the central static drilled root-planted pile 5, the lateral static drilled root-planted pile 8, and the bored cast-in-place pile 4 decrease sequentially, and the top height of the lateral static drilled root-planted pile 8 is the average of the top heights of the central static drilled root-planted pile 5 and the bored cast-in-place pile 4. A central transverse support beam 15 and a side transverse support beam 16 are respectively provided above the central static drilled pile 5 and the side static drilled pile 8. A crown beam 10 is provided above the bored pile 4. The side of the crown beam 10 is in contact with the support structure 1. Bailey beam units 17 are provided above the central transverse support beam 15 and the side transverse support beam 16, between the top of the side transverse support beam 16 and the crown beam 10. The symmetrical Bailey beam units 17 on both sides of the pipe 3 are connected by transverse connecting beams 19 to form Bailey truss beams 18. The Bailey truss beam 18 is a double-span symmetrical parallel structure. Longitudinal connecting beams 20 are provided in both spans of the Bailey truss beam 18. The Bailey beam units 17 in a single span are interconnected to form an isosceles triangle.

[0070] End plates 11 are provided between the bored piles 4, and the end plates 11 wrap around the end of the pipe 3 inside the foundation pit. A precast baffle 36 is provided below the end plates 11. Several pipe joint sleeves 23 are fitted on the pipe 3 according to the pipe joint 21. Pulleys 28 are provided on both sides of the pipe joint sleeves 23 through the lifting shaft 40. Longitudinal anchor cables 31 are provided between the pipe joint sleeves 23 and the end plates 11, and between adjacent pipe joint sleeves 23. There are also anchor cables 31 between the end plates 11 and the pipe 3, and between the pipe joint sleeves 23 and the pipe 3. Rubber sealing ring 13; Pipe fitting sleeve 23 is formed by two semi-circular sleeves 24 symmetrically connected. The ends of the semi-circular sleeves 24 are provided with mating lugs 26. The opposite mating lugs 26 are connected by pull holes 27 and tie bolts 25. The end plate 11 is provided with several anchoring ends 14. The pipe fitting sleeve 23 is provided with several cable pull lugs 29. The cable pull lugs 29 are provided with pull holes 27. The positions of the pull holes 27 and the anchoring ends 14 are corresponding. The pull holes 27 are connected to the longitudinal anchor cables 31 by bolts 30.

[0071] Each of the two sections of the Bailey truss beam 18 is equipped with a suspension system. The suspension device, along the length of the pipe 3, consists of a winch 32, a pulley 28, and a fixed end 33. One end of the steel cable 34 is connected to the fixed end 33, and the other end is connected to the winch 32 via a pipe coupling 23 and a pulley 28 on the Bailey truss beam 18. In the suspension system, the winch 32, pulley 28, and fixed end 33 are located directly above the pulley 28 of the corresponding pipe coupling 23. The distance between the pulleys 28 on both sides of the pipe coupling 23 is equal to the distance between the suspension devices on the two sections of the Bailey truss beam 18.

Claims

1. A construction method of a pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction system, characterized in that, The construction steps include the following: Step one, construction of the foundation pit retaining structure: construction of the retaining structure (1), the depth of the retaining structure (1) exceeding the deepest excavation line (2) of the foundation pit; Step two, construction of the bored piles on both sides of the pipeline: construction of the bored piles (4) on both sides of the pipeline (3); Step three, construction of the middle static drilling root pile: preliminary excavation of the ground surface (6) surrounded by the retaining structure (1) to form the preliminary excavation line (7), and then construction of the middle static drilling root pile (5), the top of the middle static drilling root pile (5) being flush with the preliminary excavation line (7); Step four, construction of the side static drilling root pile: excavation of the foundation pit to the middle of the preliminary excavation line (7) and the pipeline (3) buried depth line to form the secondary excavation line (9); synchronous construction of two pairs of side static drilling root piles (8), the top of the side static drilling root pile (8) being flush with the secondary excavation line (9); Step five, construction of the corbel and the end plate: excavation of the foundation pit to the bottom of the pipeline (3), construction of the corbel (10) on the top of the bored pile (4); local excavation of the soil (37) in the pit to form the local excavation line one (12) directly below the corbel (10), anchoring of the end plate (11) between the bored piles (4) to wrap the pipeline (3), the end plate (11) being provided with a plurality of anchor ends (14) embedded towards the side of the foundation pit; Step six, erection of the Bailey beam: hoisting of the middle transverse cushion beam (15) and the side transverse cushion beam (16), adjustment of the height of the side transverse cushion beam (16) and the middle transverse cushion beam (15), and then erection of the Bailey truss beam (18); the Bailey beam unit (17) is arranged above the middle transverse cushion beam (15) and the side transverse cushion beam (16), at the top of the side transverse cushion beam (16) and between the corbel (10), the symmetrical Bailey beam units (17) on both sides of the pipeline (3) are connected by the transverse connecting beam (19) to form the Bailey truss beam (18), the Bailey truss beam (18) being a double-column symmetrical parallel structure, the longitudinal connecting beam (20) being arranged in the double columns of the Bailey truss beam (18); the Bailey beam units (17) in the single column of the Bailey truss beam (18) are connected to each other to form an isosceles triangle. Step 7, Pipe Connection Coupling Installation and Suspension Construction: Local excavation is carried out at the pipe connection (21) to form a second excavation line (22). A rubber sealing ring (13) is installed at the pipe connection (21), and then the pipe connection coupling (23) and longitudinal anchor cable (31) are installed. The suspension system is installed on the Bailey truss beam (18) directly above the installed pipe connection coupling (23), and the steel rope (34) is connected. Then the winch (32) is slowly started for suspension. The pipe connection coupling (23) is formed by connecting a pair of semi-circular couplings (24) with tie bolts (25). The length of the pipe connection coupling (23) is the same as the diameter of the pipe (3), and the diameter of the pipe connection coupling (23) is 1.1 times the diameter of the pipe (3). The two sides of the semi-circular coupling (24) are provided with connecting lugs (26), and the connecting lugs (26) are provided with pull holes (27). The middle part of the semi-circular coupling (24) is outside A lifting shaft (40) is provided on the side, and a pulley (28) is connected to it laterally. Eight cable lugs (29) are symmetrically arranged on the pipe fitting sleeve (23). The cable lugs (29) correspond to the four anchor ends (14) on the end plate (11). The cable lugs (29) are provided with pull holes (27). The longitudinal anchor cable (31) is anchored by bolts (30). After the pipe (3) is suspended, the middle transverse pad beam (15) and the side transverse pad beam (16) are removed. The static drilled piles outside the soil (37) in the exposed pit are removed and recycled. At the same time, the excavation of the foundation pit continues. As the excavation line (38) continues to descend, the remaining static drilled piles (35) are gradually exposed outside the soil (37) in the pit. While the remaining static drilled piles (35) exposed outside the soil (37) in the pit are gradually removed and recycled, the prefabricated baffle (36) is gradually installed directly below the end plate (11).

2. The construction method of the pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction system according to claim 1, characterized in that, In step one: the support structure (1) does not cut off the pipe (3), and a safe clearance of 0.5 to 1.0 m is maintained between the support structure (1) and the pipe (3). The support structure (1) is not made directly below the cross section of the pipe (3).

3. The construction method of pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction system according to claim 1, characterized in that, In step two: the bored pile (4) and the pipeline (3) maintain a safe clearance of 2.0 to 3.0 m; the diameter of the bored pile (4) is greater than or equal to 1.0 m, the bottom depth of the bored pile (4) exceeds the depth of the retaining structure (1), and the top depth of the bored pile (4) exceeds the top of the buried pipeline (3) by 0.5 to 1.0 m.

4. The construction method of pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction system according to claim 1, characterized in that, In step seven: the degree of suspension of pipe (3) is determined by measuring the pressure below pipe (3). When the pressure below pipe (3) is zero, it indicates that the suspension of pipe (3) is complete.

5. The construction method of pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection construction system according to claim 1, characterized in that, In step seven: The suspension system includes a pair of winches (32), multiple pairs of pulleys (28) and a pair of fixed ends (33). The steel rope (34) starts from the fixed end (33), passes through the pulleys (28) on the pipe fitting sleeve (23) and the pulleys (28) on the Bailey truss beam (18) in sequence, and connects to the winch (32). Then the winch (32) is started slowly. The degree of suspension of the pipe (3) is determined by measuring the pressure below the pipe (3). When the pressure below the pipe (3) is exactly zero, it indicates that the suspension is complete.

6. A pile-slab-cable reinforced large-span foundation pit deep buried pipeline suspension protection structure, characterized in that: obtained according to the method of any one of claims 1 to 5.

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