Foundation pit supporting device and municipal road underground pipeline construction method

Abstract

The invention belongs to the technical field of municipal road underground pipeline construction, and particularly relates to a foundation pit supporting device and a municipal road underground pipeline construction method to guarantee construction safety. By arranging the foundation pit supporting device, the supporting difficulty is reduced, dismounting and mounting are convenient, the construction efficiency is effectively improved, repeated use can be achieved, resource waste is avoided, cost is saved, and the safety of construction workers in a foundation pit is guaranteed. A segmented one-time excavation mode is adopted, and a to-be-excavated road section is divided into a plurality of working sections to be excavated in a segmented mode. And after the pipeline in the previous working section foundation pit is installed, the next working section foundation pit is excavated, the foundation pit supporting device advances forwards along with the working face to enter the next working section foundation pit, and then the previous working section foundation pit is backfilled. According to line production construction of the process, the working section foundation pit is backfilled under the condition of no support, and the backfilling quality is controlled through a corresponding construction mode, so that the problem of post-construction settlement of the roadbed can be effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of municipal road underground pipeline construction, and specifically relates to a foundation pit supporting device and a municipal road underground pipeline construction method. Background Art

[0002] The construction environment of municipal road rainwater and sewage renovation projects is relatively complex, for example, there are many underground pipelines and they are close to residential houses. Therefore, the design and selection of foundation pit excavation and support schemes are the key points. If the surrounding environment of the foundation pit is not fully considered and the impact on the underground pipelines is not fully considered, and the long-distance slope excavation method is used to renovate the rainwater pipes and sewage pipes of municipal roads, when the renovation of the rainwater pipes and sewage pipes is completed and the foundation pit is backfilled, the removal of the support is likely to cause the side wall of the foundation pit to collapse, which poses a huge safety risk. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a foundation pit supporting device and a municipal road underground pipeline construction method to ensure construction safety.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a foundation pit support device, comprising a foundation pit support unit, wherein a plurality of foundation pit support units are arranged along the length direction a of the working section foundation pit, and two adjacent foundation pit support units are detachably connected through a connecting structure;

[0005] The foundation pit support unit comprises a support structure, two of which are arranged opposite to each other along the width direction b of the foundation pit of the working section and have an operating spacing;

[0006] Each of the supporting structures includes a column and a vertically arranged guard plate. There are two columns, and the two columns are arranged along the length direction a of the working section foundation pit and have a spacing therebetween; one end of the guard plate in the length direction is connected to one of the columns, and the other end is connected to the other column; the two correspondingly arranged columns in the two supporting structures are connected by a connecting support structure.

[0007] Furthermore, the connecting support structure includes a horizontal connecting rod and end plates vertically arranged at both ends of the horizontal connecting rod;

[0008] The length direction of the horizontal connecting rod is parallel to the width direction b of the foundation pit of the working section;

[0009] One of the end plates is connected to a column in one of the supporting structures, and the other end plate is connected to a corresponding column in the other supporting structure.

[0010] Furthermore, the connection support structure also includes a vertically arranged reinforcement plate, the reinforcement plate is welded to the outer side wall of the column, and the reinforcement plate is connected to the end plate by connecting bolts.

[0011] Furthermore, a vertical plate is provided at the top of the guard plate, and the length direction of the vertical plate is parallel to the length direction of the guard plate; and a hoisting hole is provided on the vertical plate;

[0012] Two vertical plates are provided, and the two vertical plates are arranged along the length direction of the guard plate and have a spacing therebetween.

[0013] Furthermore, the connection structure includes an ear plate vertically arranged and connected to the column, the length direction of the ear plate is parallel to the width direction b of the working section foundation pit, and the ear plates are arranged on both sides of the column along the width direction b of the working section foundation pit;

[0014] The two corresponding and adjacently arranged ear plates of two adjacent foundation pit supporting units are connected by fastening bolts.

[0015] Furthermore, it also includes a moving mechanism, which includes a mounting member, a horizontal support rod and a roller;

[0016] The mounting piece is connected to the column; one end of the horizontal support rod is connected to the mounting piece, and the other end extends in a direction away from the working distance;

[0017] The roller is installed through a roller seat, and the roller seat is connected to the horizontal support rod through mounting bolts. The roller is located below the horizontal support rod and placed on the road surface at the upper edge of the slope of the working section foundation pit. The rotation center of the roller is parallel to the width direction b of the working section foundation pit.

[0018] Furthermore, the top end of the column is higher than the top end of the guard plate and forms a mounting section higher than the guard plate;

[0019] The mounting member comprises a vertically arranged mounting sleeve, which is sleeved on the mounting section of the column and connected to the column via a locking bolt; one end of the horizontal support rod is connected to the outer side wall of the mounting sleeve.

[0020] Furthermore, a mounting hole is provided on the mounting section of the column, and a plurality of the mounting holes are provided, and the plurality of mounting holes are evenly distributed along the vertical direction;

[0021] The locking bolt is installed through the through hole on the installation sleeve and the installation hole on the column.

[0022] Furthermore, the horizontal support rod is provided with a connection hole, and a plurality of the connection holes are provided, and the plurality of the connection holes are evenly distributed along the length direction of the horizontal support rod;

[0023] The mounting bolts are installed through the connecting holes on the horizontal support rods and the through holes on the roller seats.

[0024] The municipal road underground pipeline construction method adopts the foundation pit support device, including the following steps:

[0025] S1, measurement and setting out;

[0026] S2, adopt the segmented excavation method, divide the road section to be excavated into several working sections for segmented excavation;

[0027] After excavating a foundation pit of a working section, a foundation pit support device is installed in the foundation pit of the working section, so that one of the support structures of the foundation pit support unit is arranged corresponding to one of the side slopes of the foundation pit of the working section, and the other support structure of the foundation pit support unit is arranged corresponding to the other side slope of the foundation pit of the working section; the bottom of the foundation pit of the working section is cleaned and leveled, and after the foundation bearing capacity of the foundation pit of the working section is tested to be qualified, a foundation sand cushion layer is laid at the bottom of the foundation pit of the working section and compacted;

[0028] S3, after removing the connection support structure of the foundation pit support device, hoist the pipeline into the foundation pit of the current working section, so that the pipeline is located in the working space between the two support structures, and the length direction of the pipeline is parallel to the length direction a of the foundation pit of the current working section, and multiple sections of pipelines are placed in sequence along the length direction a of the foundation pit of the current working section; then install the connection support structure so that the pipeline is located below the connection support structure; butt and connect two adjacent pipelines;

[0029] S4, excavate the next working section foundation pit. After the excavation of the next working section foundation pit is completed, move the foundation pit support device along the designed length direction of the foundation pit, so that one of the support structures of the foundation pit support unit is arranged corresponding to one of the slopes of the next working section foundation pit, and the other support structure of the foundation pit support unit is arranged corresponding to the other slope of the next working section foundation pit; backfill the previous working section foundation pit, so that the pipe end located in the previous working section foundation pit and arranged adjacent to the next working section foundation pit is located outside the backfill soil; clean and level the bottom of the next working section foundation pit, and after the foundation bearing capacity of the next working section foundation pit is tested to be qualified, lay a foundation sand cushion layer at the bottom of the next working section foundation pit and compact it; repeat step S3;

[0030] S5, repeating steps S3 and S4, when the installation of the pipeline in the foundation pit of the last working section is completed, removing the foundation pit support device in the foundation pit of the last working section, and then backfilling the foundation pit of the last working section.

[0031] Compared with the prior art, the beneficial effects of the present invention are: the present invention provides a foundation pit support device and a municipal road underground pipeline construction method to ensure construction safety. Specifically:

[0032] 1. The foundation pit support device reduces the difficulty of support, is easy to disassemble and assemble, effectively improves the construction efficiency, can be used repeatedly, avoids waste of resources, saves costs, and ensures the safety of construction workers in the foundation pit.

[0033] 2. Adopt the method of excavation in sections at one time, and divide the road section to be excavated into several working sections for excavation in sections. After the installation of the pipeline in the foundation pit of the previous working section is completed, the foundation pit of the next working section is excavated. The foundation pit support device moves forward with the working surface into the foundation pit of the next working section, and then backfills the foundation pit of the previous working section. According to this process, the foundation pit of the working section is backfilled without support. The backfill quality is controlled by the corresponding construction method, which can effectively avoid the problem of post-construction settlement of the roadbed. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a three-dimensional schematic diagram of the foundation pit support device;

[0035] Figure 2 yes Figure 1 A magnified view of part A in FIG.

[0036] Figure 3 yes Figure 1 A magnified view of part B in FIG.

[0037] Figure 4 yes Figure 1 The enlarged view of the C part in FIG.

[0038] Figure 5 It is a top-down structural diagram of the construction of underground pipelines in municipal roads;

[0039] Figure 6 It is a schematic diagram of the location of the foundation pit support device, the working section foundation pit and the pipeline;

[0040] Figure 7 It is a schematic diagram of the locations of the foundation pit support device, working section foundation pit, pipelines and inspection wells;

[0041] Figure numerals: 1-support structure; 101-column; 102-guard plate; 103-vertical plate; 104-mounting hole; 2-connecting support structure; 201-horizontal connecting rod; 202-end plate; 203-reinforcement plate; 204-connecting bolt; 3-ear plate; 4-moving mechanism; 401-mounting part; 402-horizontal support rod; 403-roller; 404-roller seat; 405-locking bolt; 406-mounting bolt; 407-connecting hole; 5-working space; 6-pipeline; 7-inspection well; 8-road surface; 9-excavation upper line; 10-bottom edge; 11-guardrail; 12-water retaining wall; 13-intercepting ditch. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] A foundation pit support device comprises a foundation pit support unit, wherein a plurality of foundation pit support units are arranged along the length direction a of the working section foundation pit, and two adjacent foundation pit support units are detachably connected via a connecting structure; the foundation pit support unit comprises a supporting structure 1, wherein two supporting structures 1 are arranged opposite to each other along the width direction b of the working section foundation pit and have a spacing therebetween to form a working space 5; each of the supporting structures 1 comprises a column 101 and a vertically arranged guard plate 102, wherein two columns 101 are arranged, and the two columns 101 are arranged along the length direction a of the working section foundation pit and have a spacing therebetween; one end of the guard plate 102 in the length direction is connected to one of the columns 101, and the other end is connected to the other column 101; the two correspondingly arranged columns 101 in the two supporting structures 1 are connected via a connecting support structure 2.

[0044] By setting up the support structure 1, the soil sliding down the slope can be effectively prevented from falling into the working distance 5, thereby protecting the construction personnel. The column 101 provides installation support for the guard plate 102, and the connecting support structure 2 provides connecting support for the support structure 1, effectively preventing the support structure 1 from tipping over. The outer diameter of the pipe 6 is smaller than the minimum spacing between the two support structures 1 in the foundation pit support unit. When the width of the column 101 is greater than the width of the guard plate 102, the minimum spacing is the spacing between the two corresponding columns 101 in the two support structures 1. When the width of the column 101 is less than the width of the guard plate 102, the minimum spacing is the spacing between the two guard plates 102 in the two support structures 1. The width of the column 101 and the width of the guard plate 102 are both parallel to the width direction b of the foundation pit of the working section. The guard plate 102 is connected to the column 101 by welding, clamping, etc. The foundation pit support device is a metal product such as steel and cemented carbide.

[0045] Specifically, the bottom end of one of the supporting structures 1 in the foundation pit supporting unit is arranged adjacent to one of the bottom edges 10 of the working section foundation pit, and the bottom end of another supporting structure 1 in the foundation pit supporting unit is arranged adjacent to the other bottom edge 10 of the working section foundation pit.

[0046] The connecting support structure 2 may be an X-shaped bracket. Preferably, the connecting support structure 2 includes a horizontal connecting rod 201 and end plates 202 vertically arranged at both ends of the horizontal connecting rod 201; the length direction of the horizontal connecting rod 201 is parallel to the width direction b of the working section foundation pit; one of the end plates 202 is connected to the column 101 in one of the supporting structures 1, and the other end plate 202 is connected to the corresponding column 101 in the other supporting structure 1. The horizontal connecting rod 201 is welded to the end plate 202, and the end plate 202 is welded to the column 101 or connected by bolts. Multiple groups of connecting support structures 2 may be provided, and the multiple groups of connecting support structures 2 are evenly distributed along the vertical direction.

[0047] In order to improve the connection strength, preferably, the connection support structure 2 also includes a vertically arranged reinforcing plate 203 , the reinforcing plate 203 is welded to the outer side wall of the column 101 , and the reinforcing plate 203 is connected to the end plate 202 via connecting bolts 204 .

[0048] Preferably, a vertical plate 103 is provided at the top of the guard plate 102, and the length direction of the vertical plate 103 is parallel to the length direction of the guard plate 102; a hoisting hole is provided on the vertical plate 103; two vertical plates 103 are provided, and the two vertical plates 103 are arranged along the length direction of the guard plate 102 and have a spacing. By providing the vertical plate 103, it is convenient for a hoisting device to hoist the guard plate 102. Specifically, the vertical plate 103 is welded to the guard plate 102.

[0049] Specifically, the connection structure includes an ear plate 3 which is vertically arranged and connected to the column 101, the length direction of the ear plate 3 is parallel to the width direction b of the working section foundation pit, and the ear plates 3 are arranged on both sides of the column 101 along the width direction b of the working section foundation pit; the two corresponding and adjacent ear plates 3 of two adjacent foundation pit support units are connected by fastening bolts.

[0050] Preferably, a moving mechanism 4 is also included, the moving mechanism 4 includes a mounting member 401, a horizontal support rod 402 and a roller 403; the mounting member 401 is connected to the column 101; one end of the horizontal support rod 402 is connected to the mounting member 401, and the other end extends in a direction away from the working space 5; the roller 403 is installed through a roller seat 404, and the roller seat 404 is connected to the horizontal support rod 402 through a mounting bolt 406. The roller 403 is located below the horizontal support rod 402 and is placed on the road surface 8 at the upper edge of the slope of the working section foundation pit, and the rotation center of the roller 403 is parallel to the width direction b of the working section foundation pit. By setting the moving mechanism 4, it is convenient to move the foundation pit support device.

[0051] The mounting member 401 may be a vertically arranged mounting plate, which is connected to the column 101 by welding or bolts. Preferably, the top of the column 101 is higher than the top of the guard plate 102, and forms a mounting section higher than the guard plate 102; the mounting member 401 includes a vertically arranged mounting sleeve, which is sleeved on the mounting section of the column 101 and connected to the column 101 by a locking bolt 405; one end of the horizontal support rod 402 is connected to the outer side wall of the mounting sleeve. Specifically, one end of the horizontal support rod 402 is welded to the outer side wall of the mounting sleeve.

[0052] In order to adapt to the working section foundation pits of different depths, preferably, a mounting hole 104 is opened on the mounting section of the column 101, and a plurality of mounting holes 104 are provided, and the plurality of mounting holes 104 are evenly distributed in the vertical direction; the locking bolt 405 is installed through the through hole on the mounting sleeve and the mounting hole 104 on the column 101.

[0053] Preferably, a plurality of mounting holes 104 arranged along the vertical direction form a mounting hole group, and two mounting hole groups are arranged, and the two mounting hole groups are arranged along the length direction a of the working section foundation pit and have a spacing therebetween.

[0054] In order to adapt to working section foundation pits of different widths, preferably, a connecting hole 407 is opened on the horizontal support rod 402, and a plurality of connecting holes 407 are provided, and the plurality of connecting holes 407 are evenly distributed along the length direction of the horizontal support rod 402; the mounting bolt 406 is installed through the connecting hole 407 on the horizontal support rod 402 and the through hole on the roller seat 404.

[0055] The municipal road underground pipeline construction method adopts the foundation pit support device, including the following steps:

[0056] S1, measurement and layout.

[0057] The surveying and setting out includes re-surveying and verifying the control piles according to the design drawings. After confirmation, the control piles and leveling points are encrypted according to the construction needs. After the control piles and leveling points are encrypted, the original landform is re-surveyed, the excavation upper line 9 is released and clearly marked with lime line.

[0058] S2, adopt the segmented excavation method, divide the road section to be excavated into several working sections and excavate them in sections.

[0059] Before the segmented excavation, the original road structure layer needs to be broken. After the construction site is closed and fenced, the original road structure layer is first cut with an average thickness of 20cm, and then the original road structure layer is broken.

[0060] Preferably, the length of each working section foundation pit is 6 meters. Specifically, an excavator is used to excavate the working section foundation pit. The slope ratio of each working section foundation pit is 1: (0.31-0.41).

[0061] When the construction depth of the working section foundation pit exceeds 2 meters, guardrails 11 are arranged on the outer sides of the two foundation pit excavation upper opening lines 9. The guardrails 11 are steel frame structures. In order to prevent rainwater from entering, a retaining wall 12 is also built on the outer side of the guardrail 11, and a drainage ditch 13 is built on the outer side of the retaining wall 12. The retaining wall 12 is a reinforced concrete structure. That is to say, the guardrails 11, the retaining wall 12 and the drainage ditch 13 are arranged in sequence in the direction away from the foundation pit excavation upper opening line 9.

[0062] After excavating a working section foundation pit, a foundation pit support device is installed in the working section foundation pit, so that one of the support structures 1 of the foundation pit support unit is arranged corresponding to one of the slopes of the working section foundation pit, and the other support structure 1 of the foundation pit support unit is arranged corresponding to the other slope of the working section foundation pit; the bottom of the working section foundation pit is cleaned and leveled, and after the foundation bearing capacity of the working section foundation pit is tested to be qualified, a foundation sand cushion layer is laid at the bottom of the working section foundation pit and compacted.

[0063] Specifically, the bottom end of one of the supporting structures 1 in the foundation pit supporting unit is arranged adjacent to one of the bottom edges 10 of the foundation pit of the working section, and the bottom end of another supporting structure 1 in the foundation pit supporting unit is arranged adjacent to the other bottom edge 10 of the foundation pit of the working section.

[0064] Preferably, a compaction degree test is performed after compaction.

[0065] Preferably, construction workers enter the working space 5 between the two supporting structures 1 by climbing a ladder, and the guard plate 101 of the supporting structure 1 provides support for the installation of the ladder.

[0066] S3, after removing the connecting support structure 2 of the foundation pit support device, hoist the pipeline 6 into the foundation pit of this working section, so that the pipeline 6 is located in the working space 5 between the two supporting structures 1, and the length direction of the pipeline 6 is parallel to the length direction a of the foundation pit of this working section, and multiple sections of pipeline 6 are placed in sequence along the length direction a of the foundation pit of this working section; then install the connecting support structure 2, so that the pipeline 6 is located below the connecting support structure 2; dock and connect two adjacent pipelines 6.

[0067] The foundation pit of this working section refers to the working section foundation pit that has been excavated after the foundation sand cushion layer is laid and compacted at the bottom.

[0068] S4, excavate the next working section foundation pit. After the excavation of the next working section foundation pit is completed, move the foundation pit support device along the designed length direction of the foundation pit, so that one of the support structures 1 of the foundation pit support unit is arranged corresponding to one of the slopes of the next working section foundation pit, and the other support structure 1 of the foundation pit support unit is arranged corresponding to the other slope of the next working section foundation pit; backfill the previous working section foundation pit, so that the end of the pipeline 6 located in the previous working section foundation pit and arranged adjacent to the next working section foundation pit is located outside the backfill soil; clean and level the bottom of the next working section foundation pit, and after the foundation bearing capacity of the next working section foundation pit is tested to be qualified, lay a foundation sand cushion layer at the bottom of the next working section foundation pit and compact it; repeat step S3.

[0069] Preferably, a compaction degree test is performed after compaction.

[0070] Specifically, the bottom end of one of the supporting structures 1 in the foundation pit supporting unit is arranged adjacent to one of the bottom edges 10 of the next working section foundation pit, and the bottom end of another supporting structure 1 in the foundation pit supporting unit is arranged adjacent to the other bottom edge 10 of the next working section foundation pit.

[0071] S5, repeating steps S3 and S4, when the installation of the pipeline 6 in the foundation pit of the last working section is completed, removing the foundation pit supporting device in the foundation pit of the last working section, and then backfilling the foundation pit of the last working section.

[0072] Backfill the working section foundation pit. Specifically, first backfill gravel in the working section foundation pit and tamp it to form a gravel layer, and then backfill earth on the gravel layer and tamp it to form an earth layer, so that the earth layer is flush with the roadbed.

[0073] Preferably, a manhole 7 is built every 40 to 50 meters, and the pipe 6 is connected to the inner cavity of the manhole 7, and the manhole 7 is connected to the pipe 6 on both sides of the axial direction. The top of the manhole 7 is higher than the road surface 8, and the manhole 7 is located in the working space 5. The outer diameter of the manhole 7 is smaller than the minimum spacing between the two supporting structures 1 in the foundation pit support unit. When the width of the column 101 is greater than the width of the guard plate 102, the minimum spacing is the spacing between the two corresponding columns 101 in the two supporting structures 1. When the width of the column 101 is less than the width of the guard plate 102, the minimum spacing is the spacing between the two guard plates 102 in the two supporting structures 1. When there is a manhole 7 in the working space 5 of the foundation pit support device, first remove the part of the connecting support structure 2 that interferes with the movement of the foundation pit support device, and then move the foundation pit support device along the design length direction of the foundation pit. When the foundation pit support device with part of the connecting support structure 2 removed reaches the foundation pit of the next working section, the removed part of the connecting support structure 2 is installed.

[0074] The embodiments of this specific implementation are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A foundation pit support device, characterized in that: It comprises a foundation pit support unit, wherein a plurality of foundation pit support units are arranged along the length direction a of the foundation pit of the working section, and two adjacent foundation pit support units are detachably connected via a connecting structure; The foundation pit support unit comprises a support structure (1), wherein two support structures (1) are provided, and the two support structures (1) are arranged opposite to each other along a width direction b of the foundation pit of the working section and have a working space (5); Each of the supporting structures (1) comprises a column (101) and a vertically arranged guard plate (102); two columns (101) are provided, and the two columns (101) are arranged along the length direction a of the working section foundation pit and have a spacing; one end of the guard plate (102) in the length direction is connected to one of the columns (101), and the other end is connected to the other column (101); the two columns (101) arranged correspondingly in the two supporting structures (1) are connected via a connecting support structure (2).

2. The foundation pit supporting device according to claim 1, characterized in that: The connecting support structure (2) comprises a horizontal connecting rod (201) and end plates (202) vertically arranged at both ends of the horizontal connecting rod (201); The length direction of the horizontal connecting rod (201) is parallel to the width direction b of the working section foundation pit; One of the end plates (202) is connected to a column (101) in one of the supporting structures (1), and the other end plate (202) is connected to a corresponding column (101) in another supporting structure (1).

3. The foundation pit supporting device according to claim 2, characterized in that: The connecting support structure (2) further comprises a reinforcing plate (203) arranged vertically, wherein the reinforcing plate (203) is connected to the outer side wall of the column (101) by welding, and the reinforcing plate (203) is connected to the end plate (202) by connecting bolts (204).

4. The foundation pit supporting device according to claim 1, characterized in that: A vertical plate (103) is provided at the top of the guard plate (102), and the length direction of the vertical plate (103) is parallel to the length direction of the guard plate (102); and a hoisting hole is provided on the vertical plate (103); Two vertical plates (103) are provided, and the two vertical plates (103) are arranged along the length direction of the guard plate (102) and have a spacing therebetween.

5. The foundation pit supporting device according to claim 1, characterized in that: The connection structure comprises an ear plate (3) which is arranged vertically and connected to the column (101); the length direction of the ear plate (3) is parallel to the width direction b of the working section foundation pit; the ear plates (3) are arranged on both sides of the column (101) along the width direction b of the working section foundation pit; The two ear plates (3) of two adjacent foundation pit support units that are corresponding and arranged adjacently are connected via fastening bolts.

6. The foundation pit supporting device according to claim 1, characterized in that: It also includes a moving mechanism (4), wherein the moving mechanism (4) includes a mounting member (401), a horizontal support rod (402) and a roller (403); The mounting member (401) is connected to the column (101); one end of the horizontal support rod (402) is connected to the mounting member (401), and the other end extends in a direction away from the working space (5); The roller (403) is installed via a roller seat (404), and the roller seat (404) is connected to the horizontal support rod (402) via a mounting bolt (406). The roller (403) is located below the horizontal support rod (402) and is placed on the road surface (8) at the upper edge of the slope of the working section foundation pit. The rotation center of the roller (403) is parallel to the width direction b of the working section foundation pit.

7. The foundation pit supporting device according to claim 6, characterized in that: The top end of the column (101) is higher than the top end of the guard plate (102), and forms a mounting section higher than the guard plate (102); The mounting member (401) comprises a vertically arranged mounting sleeve, which is sleeved on the mounting section of the column (101) and connected to the column (101) via a locking bolt (405); one end of the horizontal support rod (402) is connected to the outer side wall of the mounting sleeve.

8. The foundation pit supporting device according to claim 7, characterized in that: The mounting section of the column (101) is provided with a mounting hole (104), a plurality of the mounting holes (104) are provided, and the plurality of the mounting holes (104) are evenly distributed along the vertical direction; The locking bolt (405) is installed by passing through the through hole on the installation sleeve and the installation hole (104) on the column (101).

9. The foundation pit supporting device according to claim 6, characterized in that: The horizontal support rod (402) is provided with a connection hole (407), and a plurality of the connection holes (407) are provided, and the plurality of the connection holes (407) are evenly distributed along the length direction of the horizontal support rod (402); The mounting bolt (406) is installed by passing through the connecting hole (407) on the horizontal support rod (402) and the through hole on the roller seat (404).

10. A method for constructing underground pipelines on municipal roads, characterized in that: The foundation pit supporting device according to any one of claims 1 to 9 comprises the following steps: S1, measurement and setting out; S2, adopt the segmented excavation method, divide the road section to be excavated into several working sections for segmented excavation; After excavating a working section foundation pit, a foundation pit support device is installed in the working section foundation pit, so that one of the support structures (1) of the foundation pit support unit is arranged corresponding to one of the side slopes of the working section foundation pit, and the other support structure (1) of the foundation pit support unit is arranged corresponding to the other side slope of the working section foundation pit; the bottom of the working section foundation pit is cleaned and leveled, and after the foundation bearing capacity of the working section foundation pit is tested to be qualified, a foundation sand cushion layer is laid at the bottom of the working section foundation pit and compacted; S3, after removing the connection support structure (2) of the foundation pit support device, hoist the pipeline (6) into the foundation pit of the current working section, so that the pipeline (6) is located in the working space (5) between the two support structures (1), the length direction of the pipeline (6) is parallel to the length direction a of the foundation pit of the current working section, and multiple sections of pipeline (6) are placed in sequence along the length direction a of the foundation pit of the current working section; then install the connection support structure (2) so that the pipeline (6) is located below the connection support structure (2); and butt and connect two adjacent pipelines (6); S4, excavating the foundation pit of the next working section, after the excavation of the foundation pit of the next working section is completed, moving the foundation pit support device along the designed length direction of the foundation pit, so that one of the support structures (1) of the foundation pit support unit is arranged corresponding to one of the side slopes of the foundation pit of the next working section, and the other support structure (1) of the foundation pit support unit is arranged corresponding to the other side slope of the foundation pit of the next working section; backfilling the foundation pit of the previous working section, so that the end of the pipeline (6) located in the foundation pit of the previous working section and arranged adjacent to the foundation pit of the next working section is located outside the backfill soil; The bottom of the foundation pit of the next working section is cleaned and leveled, and after the foundation bearing capacity of the foundation pit of the next working section is tested to be qualified, a foundation sand cushion layer is laid at the bottom of the foundation pit of the next working section and compacted; step S3 is repeated; S5, repeating steps S3 and S4, when the installation of the pipeline (6) in the foundation pit of the last working section is completed, removing the foundation pit support device in the foundation pit of the last working section, and then backfilling the foundation pit of the last working section.

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