CN218933157U

CN218933157U - Backfill structure for pipeline construction

Info

Publication number: CN218933157U
Application number: CN202221786870.2U
Authority: CN
Inventors: 战福军
Original assignee: Nanjing Lianzhong Engineering Technology Co ltd
Current assignee: Nanjing Lianzhong Engineering Technology Co ltd
Priority date: 2021-10-22
Filing date: 2022-07-12
Publication date: 2023-04-28
Anticipated expiration: 2032-07-12
Also published as: CN115075265A; CN217758400U; CN114134831A; CN114673172A; CN217870532U

Abstract

The utility model discloses a backfill structure for pipeline construction, wherein a pipeline is paved at the bottom of a foundation pit arranged on the surface of a rammed roadbed; the pit bottom of the foundation pit is an arc-shaped surface; cushion blocks for adjusting the straightness and levelness of the pipeline are paved at the shoulders and the bottoms of the left side and the right side of the pipeline, and a fluid self-compaction quick-setting pouring medium is filled between the pipeline and the inner wall of the foundation pit. After the pipeline is placed in the foundation pit, injecting a fluid self-compaction quick-setting pouring medium into the bottom of the pipeline from one side, and stopping the first pouring when the gap between the bottom of the pipeline and the bottom of the foundation pit is completely filled by the fluid self-compaction quick-setting pouring medium; after the medium is solidified, pouring the fluid self-compaction quick-setting pouring medium from two sides of the pipeline for multiple times until the fluid self-compaction quick-setting pouring medium completely coats the outer surface of the pipeline. The backfill structure performs dense backfill on all parts around the pipeline, and can fully exert the excellent performance of the pipeline culvert.

Description

Backfill structure for pipeline construction

Technical Field

The utility model belongs to the technical field of civil engineering, and particularly relates to a backfill structure for pipeline construction.

Background

The construction of the pipeline, the backfilling operation of the bottom and the backfilling compaction of the side are difficult to operate, the backfilling compaction is difficult to meet the requirements, and according to the design research, the manufacture and the construction experience of the corrugated steel pipe, the corrugated steel pipe has the advantages of light weight, low manufacturing cost, strong adaptive deformation capability, no special treatment on the foundation and the like because of the assembled structure of the corrugated steel pipe, and is applied to many highway projects.

However, in actual construction, backfill of a wedge-shaped part formed by the bottom of the pipe and the foundation is difficult to tamp, and if a wood rod is used for tamping, the pipe body floats upwards or is offset left and right, and if the part is not tamped, the pipe body is deformed, so that in few projects, the part is compacted by adopting a coarse sand watertight method, but the cost of the method is too high, coarse sand sources are limited, and the method is rarely used. In addition, backfilling of the two sides of the pipe body has a thickness of about 20-30 cm, which cannot be compacted, because the tamping machine needs to keep a certain safe distance from the pipe body so as not to hurt the pipe body. In addition, when the thickness of backfill soil at the top of the outer pipe body reaches about 50 cm, a small-sized tamping machine is allowed to be used so as to avoid impact damage to the pipe body, and the bottom layer of the backfill soil with the thickness cannot meet the compactness requirement. In summary, in practical engineering use, it is difficult to achieve the backfill quality required by design, and the quality problems such as deformation of the steel corrugated pipe culvert are often caused.

In the prior art, the caliber of a reinforced concrete circular pipe culvert used in a small-caliber pipe culvert in highway engineering is generally 1 meter, 1.5 meters or 2 meters, and the circular pipe culvert cannot adapt to foundation settlement and other reasons because each section is short (the length is generally 2 meters), the construction quality is high, the measures are multiple, the manufacturing cost is high, the foundation bearing capacity is generally greater than the peripheral bearing capacity, a concrete cushion layer is arranged, a pipe body is arranged on the cushion layer, the pipe sections are required to be sealed, then the concrete of a wedge-shaped part between the pipe body and the foundation cushion layer is cast by a formwork, then the two side backs of the pipe body are cast by the formwork support concrete, and structural backfilling of two sides is carried out until the pipe top is carried out after the concrete is solidified.

According to the traditional construction method, when the distance between adjacent culverts is relatively short and the number of the culverts is relatively large, the culverts divide the roadbed into a plurality of sections, the working face of the construction machine between the culverts is not large, the working efficiency of the construction machine is low, and in addition, the special backfill areas on two sides of the culverts are high in construction requirement due to the fact that the special backfill areas are close to the culverts, the construction speed is low, and large-area tamping is not easy to expand.

Disclosure of Invention

The utility model aims to: the utility model aims to provide a backfill structure for pipeline construction.

The technical scheme is as follows: in order to achieve the aim of the utility model, the utility model discloses a backfill structure for pipeline construction, wherein a pipeline is paved at the bottom of a foundation pit arranged on the surface of a rammed roadbed; the fluid self-compaction quick-setting filling medium is filled between the pipeline and the inner wall of the foundation pit, and the top surface of the fluid self-compaction quick-setting filling medium is higher than the top surface of the pipeline.

Preferably, the top of the foundation pit is provided with a stepped groove.

Preferably, the pit bottom of the foundation pit is an arc-shaped surface.

Preferably, the width of the foundation pit is 10 cm greater than the outer diameter of the pipeline; when the pipeline is paved at the bottom of the foundation pit, the height between the opening at the top of the foundation pit and the top of the pipe is not less than 20 cm.

Preferably, the pipeline is formed by splicing a plurality of pipeline sections.

Preferably, the fluid self-compaction quick setting pouring medium adopts cement soil or foaming concrete or concrete mortar.

Preferably, the soil cement raw materials include foundation pit spoil and cement, as well as other additives.

Preferably, the shoulder parts and the bottom parts of the left side and the right side of the pipeline are paved with cushion blocks for adjusting the straightness and the levelness of the pipeline.

Further, when the pit bottom of the foundation pit formed by digging on the surface of the rammed roadbed is an arc surface, the pit bottom edge of the vertical section of the foundation pit is semicircular in general, the circular diameter of the pit bottom edge is larger than the outer diameter of the pipeline, and when the pipeline is paved on the pit bottom of the foundation pit, under the action of gravity, the pipeline and a cushion block at the bottom of the pipeline automatically slide to the central position of the pit bottom, so that the pipeline positioning is facilitated. The fluid self-compaction rapid hardening pouring medium injected between the pipeline and the inner wall of the foundation pit can self-compactly fill all gaps between the corrugated pipe and the inner wall of the foundation pit, including wedge-shaped gaps between the bottom of the corrugated pipe and the bottom surface of the foundation pit.

Further, the semicircular pit bottom of the foundation pit is more stable than the straight pit bottom structure perpendicular to the side wall, and is not easy to collapse.

Furthermore, the cement soil prepared from the excavated foundation pit spoil and high-grade cement is used as a fluid self-compaction quick-setting pouring medium, so that the material cost and the construction cost can be greatly reduced, and the method is economical and environment-friendly. The strength of cement soil prepared from the foundation pit spoil and high-grade cement is not less than 0.6Mpa.

Further, the pipeline is transported to a construction site after being cut into segments at a factory, and is placed in a foundation pit after being formed into a continuous pipeline by in-situ welding in sequence along a splicing seam at the site.

Further, after the fluid self-compaction quick-setting filling medium is injected into the foundation pit, the thickness of the fluid self-compaction quick-setting filling medium at the top is not less than 20 cm, and at the moment, the strength of the solidified medium can protect the pipeline from being damaged by large-scale tamping machinery in the subsequent construction.

Further, the top lateral wall of foundation ditch is echelonment, and the medium layer width of echelonment foundation ditch top messenger pouring back pipeline top is accomplished to the echelonment, and there is the ramming road bed support below the medium layer that is located foundation ditch echelonment structure above the pipeline, is favorable to reducing the impact or the damage of follow-up pipeline top large-scale ramming machine to the pipeline. The depth of the foundation pit top step is determined according to the depth of the foundation pit and the diameter of the pipeline.

The backfill structure for pipeline construction comprises the following steps:

(1) Assembling and connecting the multiple sections of pipelines beside the planned path of the foundation pit to form a whole pipeline, wherein the pipeline structure meets the connection strength required by hoisting the whole pipeline;

(2) Digging a foundation pit at a target position, and integrally hoisting the whole pipeline with the connected multi-section pipeline into the foundation pit at one time in target time;

(3) Laying cushion blocks at the shoulders and the bottoms of the left side and the right side of the pipeline, and adjusting the straightness and levelness of the pipeline;

(4) After an anti-floating device is arranged at the upper part of the pipeline, injecting a fluid self-compaction quick-setting pouring medium into a gap between the pipeline and the side wall of the foundation pit from one side, and stopping pouring for the first time until the fluid self-compaction quick-setting pouring medium overflows from the bottom of the pipeline to the other side until the pouring height of the medium exceeds the shoulder of the pipeline;

(5) And after the first-poured fluid self-compaction rapid hardening pouring medium is solidified, removing the anti-floating device, and pouring the fluid self-compaction rapid hardening pouring medium on the top of the pipeline until the fluid self-compaction rapid hardening pouring medium completely coats the outer surface of the pipeline.

And (3) after the foundation pit is excavated, the pipeline is integrally hung into the foundation pit in one time within 4 hours.

Further, the anti-floating device is a limiting steel frame or a sand bag paved on the pipe top of the pipeline.

Further, after the outer surface of the pipeline is completely coated by the fluid self-compaction rapid hardening pouring medium, the thickness of the fluid self-compaction rapid hardening pouring medium at the top is not less than 20 cm.

Further, after the pipeline is laid in the foundation pit, if the distance between the top of the foundation pit and the top of the pipeline is less than 20 cm, the brackets on two sides of the foundation pit are used for pouring a template of the fluid self-compaction rapid hardening pouring medium above the pipeline.

Further, unlike the conventional construction method, when the road base is constructed to the bottom of the designed position of the pipeline, the construction of the pipeline is not performed, but the upward construction is continued and the roadbed is tamped, and when the height of the tamped roadbed exceeds the designed position of the top of the culvert by at least 20 cm, the special trenching machine is used for excavating the pipeline foundation pit. Cleaning and compacting the side wall and the bottom surface of the foundation pit after the foundation pit with the bottom surface in the arc shape is excavated by the ditching machine, and digging through the foundation pit at one time according to the set length; the depth of the excavated foundation pit exceeds the diameter of the pipeline by at least 20 cm, and the width of the foundation pit is larger than the diameter of the pipeline by 10 cm. The foundation pit with the circular arc bottom surface can reduce disturbance to surrounding soil and loosening of the surrounding soil. After the foundation pit is excavated, the pipeline is hung into the foundation pit within 4 hours, and the fluid self-compaction quick-setting pouring medium is poured, so that the soil body can be prevented from loosening or collapsing after the foundation pit is empty for a long time.

Furthermore, the foundation pit is excavated on the rammed roadbed to replace backfill soil backfill in the prior art, so that the construction speed of the roadbed taking the height of a pipeline as a thickness part is improved, and the expansion of a working face of a construction machine during the construction of the roadbed with the thickness is also facilitated.

Further, a plurality of prefabricated pipeline sections of a factory can be welded along a splicing seam to form a continuous whole pipeline, the length of the whole pipeline reaches the total length of the pipeline design, the whole pipeline which is connected is placed into a foundation pit at one time by utilizing a plurality of lifting devices, the pipeline is laid, and the strength of the pipeline connection part of the continuous whole pipeline formed by splicing can meet the lifting requirement of lifting the whole pipeline.

Further, after the pipeline is laid, the fluid self-compaction quick-setting filling medium can be poured from one side of the pipeline in the first pouring stage until the fluid self-compaction quick-setting filling medium completely compactly fills the wedge-shaped space between the bottom of the pipeline and the foundation pit, and the solidified fluid self-compaction quick-setting filling medium is tightly combined with the pipeline, so that the pipeline is initially limited and the counterweight is increased.

When the steel corrugated pipe is adopted in the pipeline, the outer wall of the steel corrugated pipe is in a spiral corrugated shape, a cushion block is arranged below the pipeline, a gap exists between the pipeline and the bottom surface of the foundation pit, and a fluid self-compaction quick-setting filling medium poured from one side overflows to the other side through the gap until the liquid level on the other side of the steel corrugated pipe culvert can completely cover the gap between the outer wall of the bottom of the steel corrugated pipe culvert and the bottom surface of the foundation pit, and after the fluid self-compaction quick-setting filling medium is solidified, the fluid self-compaction quick-setting filling medium and the corrugated pipe are tightly combined. By means of single-side injection and overflow filling from bottom to top, bubbles and cavities can not be generated in the filling medium.

The follow-up pouring process can be cast by the pipeline both sides for several times, and the both sides are cast in proper order can prevent that too many to pipeline of homonymy once casting from producing the extrusion, causes the pouring quality to descend. The final casting was stopped 20 cm above the top of the pipe. The solidified fluid self-compaction quick-setting filling medium and the surrounding compacted backfill soil form an integral coating on the pipe body, a layer of roadbed layer can be directly paved on the top of the structure, and a large-scale compacting machine can be used for compacting. The foundation pit with the arc bottom surface can reduce the use amount and the engineering amount of the fluid self-compaction quick-setting filling medium.

When the depth of the foundation pit cannot meet the requirement that the depth of the foundation pit exceeds the diameter of the pipeline by 20 cm, the self-compaction quick-setting pouring medium in the flow state can be poured into the templates of the brackets on two sides above the foundation pit, after the self-compaction quick-setting pouring medium in the flow state is solidified, a medium layer with enough thickness can be formed above the pipeline, the protection of the pipeline is finished, the heights of the templates of the brackets on two sides above the foundation pit can be determined according to the depth of the foundation pit and the diameter of the pipeline, and the thickness of the medium layer above the pipeline is ensured to be more than 20 cm.

The beneficial effects are that: compared with the prior art, the utility model has the following remarkable advantages: according to the technical method, a foundation pit is formed by directly excavating on a rammed roadbed, a pipeline is placed in the foundation pit with the bottom surface in the shape of a circular arc, a fluid self-compaction quick-setting pouring medium is injected into the periphery of the pipeline, and after solidification of the fluid self-compaction quick-setting pouring medium, compact backfilling of all parts around the pipeline, particularly wedge-shaped spaces between the bottom of the pipeline and the foundation pit, is completed. The solidified fluid self-compaction rapid hardening perfusion medium covers the whole pipeline, can protect the whole pipeline, and fully plays the superior performance of the pipeline. In addition, the filling method of the fluid self-compaction rapid hardening filling medium in the foundation pit can ensure that no bubbles and voids exist in the filling medium.

Drawings

FIG. 1 is a schematic view of a vertical cross-section of a pipe laid in a foundation pit according to the present utility model;

FIG. 2 is a schematic view of the cross-sectional structure A-A of FIG. 1;

FIG. 3 is a schematic illustration of the position of a fluid self-compacting rapid hardening infusion medium after a first pour in accordance with the present utility model;

FIG. 4 is a schematic view of the structure of the pouring medium of the present utility model when the pouring medium is poured to a set height;

FIG. 5 is a schematic view of a stepped structure of a side wall of a foundation pit according to the present utility model;

FIG. 6 is a schematic diagram of the structure of a support template above a foundation pit in the utility model;

FIG. 7 is a schematic view of a prior art construction for backfilling a pipe with backfill;

fig. 8 is a schematic diagram of a prior art reinforced concrete round tube culvert backfill structure.

Detailed Description

In the prior art, backfill construction is carried out on a pipeline culvert through surrounding backfill soil, as shown in fig. 7, but during actual construction, the backfill soil 8 in the wedge-shaped structure 7 between the pipeline 4 and the roadbed 1 is difficult to tamp, so that the construction difficulty and the construction cost are greatly improved, and the construction quality is difficult to guarantee. The concrete round tube culvert 12 needs to be laid with a concrete cushion layer 9 in advance due to heavy weight and incapability of adapting to foundation settlement, the concrete round tube culvert 12 is laid on the concrete cushion layer 9, after the joints of all the concrete round tubes are sealed, the wedge-shaped part between the bottom of the concrete round tube culvert 12 and the concrete cushion layer 9 is poured with concrete 10 by formwork casting, after the concrete is solidified, the formwork-supported concrete is continued to be poured with concrete backs 11 on two sides of the tube body of the concrete round tube culvert 12, and after the concrete is solidified, the structural backfilling of two sides is carried out by backfilling concrete 8 until the tube top is achieved, as shown in fig. 8.

In view of the foregoing drawbacks of the prior art, the following describes in further detail the technical solution of the present utility model with reference to the accompanying drawings and examples.

In a backfill structure for pipe construction, as shown in fig. 1, a foundation pit 2 is formed by excavating a previously compacted roadbed 1 in a set extending direction, and the thickness of the roadbed 1 exceeds the outer diameter of a pipe 4. The pit bottom surface of the foundation pit 2 is a semicircular arc surface 3, the deepest depth of the foundation pit 2 is larger than the outer diameter of the pipeline 4 by 20 cm, and the width of the foundation pit 2 is larger than the outer diameter of the pipeline 4 by 10 cm.

The pipeline 4 is paved at the bottom of the foundation pit 2, a fluid self-compaction rapid hardening pouring medium 5 is filled between the outer wall of the pipeline 4 and the inner wall of the foundation pit 2, and the top surface of the fluid self-compaction rapid hardening pouring medium 5 filled in the foundation pit 2 is higher than the top surface of the corrugated pipe 4 by 20 cm. The self-compaction quick-setting pouring medium 5 in the flow state is solidified and then is compacted with the surrounding roadbed structure, and the whole coating of the pipeline 4 is completed.

In this embodiment, the pipe 4 is prefabricated in a factory, and for convenience in transportation, the pipe is cut into pipe sections with a set length in the factory, marked in sequence, transported to the site, arranged in cutting sequence according to the designed length and the extending direction, and welded in situ along the splicing seam 13 to form a continuous whole pipe 4, and the continuous whole corrugated pipe 4 is laid at the bottom of the foundation pit 2, as shown in fig. 2.

Further, the fluid self-compaction quick setting pouring medium 5 can be cement soil or foaming concrete or concrete mortar. In the embodiment, the fluid self-compaction quick-setting pouring medium 5 adopts cement soil, the cement soil manufacturing raw materials comprise high-grade cement, soil produced by excavation of the foundation pit 2 and other additives, and the strength of the obtained cement soil is not lower than 0.6MPa.

In this embodiment, after the pipeline 4 is entirely covered with the fluid self-compaction quick-setting filling medium 5, the remaining space of the foundation pit 2 is backfilled with backfill soil, and after the large-scale compaction machine is directly used for compaction, the pavement 6 is paved on the surface of the roadbed 1.

Further, as shown in fig. 5, the side wall of the top of the foundation pit is provided with a stepped groove 14, the width of the stepped groove 14 is larger than that of the bottom of the foundation pit 2, the foundation pit 2 provided with the stepped groove 14 increases the width of a medium layer above the pipeline 4 after casting is completed, and the tamping roadbed 1 is supported below the medium layer above the pipeline 4 and positioned in the stepped groove 14, so that impact or damage of a large tamping machine above the subsequent pipeline 4 to the pipeline is reduced. The depth of the stepped groove 14 at the top of the foundation pit 2 is determined according to the depth of the foundation pit 2 and the diameter of the pipeline 4.

The construction method of the pipeline in the embodiment comprises the following steps:

(1) When the foundation is constructed to the bottom of a pipeline laying design position, the pipeline laying construction is not carried out, the foundation is continuously constructed upwards and is compacted until the height of the foundation exceeds 20 cm of the pipeline position, the thickening operation of the foundation is stopped, a plurality of pipeline segments prefabricated in a factory are welded along splicing seams to form a continuous whole pipeline around the foundation pit design position before the foundation pit is excavated, after the pipeline assembly is completed, a special excavator with an arc-shaped digging cutter is utilized to dig a foundation pit on the surface of the foundation pit, the bottom surface of the foundation pit is a semicircular arc-shaped surface, the deepest depth of the foundation pit 2 is larger than 20 cm of the outer diameter of the pipeline 4, and the width of the foundation pit 2 is larger than 10 cm of the outer diameter of the pipeline 4; and cleaning and compacting the arc bottom surface and the side wall of the foundation pit. The foundation pit is excavated once and is excavated through, and the design length is reached according to the design extension direction.

(2) And (3) within 4 hours after excavation of the foundation pit is completed, the whole pipeline after connection is lifted into the foundation pit by utilizing a plurality of lifting devices at one time, and cushion blocks are paved at the shoulder parts and the bottom parts of the left side and the right side of the pipeline to adjust the straightness and the levelness of the pipeline.

(3) After the anti-floating device is arranged at the upper part of the pipeline, the fluid self-compaction quick-setting pouring medium is injected into the gap between the pipeline and the side wall of the foundation pit from one side, and overflows from the bottom of the pipeline to the other side until the pouring height of the medium exceeds the shoulder of the pipeline, and the first pouring is stopped as shown in fig. 3.

(4) After the first poured fluid self-compaction rapid hardening pouring medium is solidified, the anti-floating device is removed, the fluid self-compaction rapid hardening pouring medium is poured from the two sides of the pipeline in a divided mode, the pouring height of each time is 20 cm, and the outer surface of the pipeline is completely covered by the fluid self-compaction rapid hardening pouring medium, as shown in fig. 4.

(5) And continuously pouring the medium above the pipeline until the medium exceeds the top of the pipeline by 20 cm, stopping pouring, and after the medium is solidified, if an unfilled space exists above the foundation pit, filling and tamping the rest space by using backfill.

(6) Paving the surface of the roadbed to form a pavement.

In this embodiment, the anti-floating device is a limiting steel frame or a sand bag laid on the pipeline, and is used for providing downward pressure for the pipeline no matter the limiting steel frame or the sand belt is adopted, so that the pipe body of the pipeline is prevented from floating after the fluid self-compaction quick-setting pouring medium is injected.

When the bottom surface of the excavated foundation pit is an arc surface, the foundation pit structure is more stable and is not easy to collapse, the excavation amount is reduced, the disturbance to surrounding soil is reduced, and the positioning of a pipeline is facilitated by the arc bottom surface of the foundation pit. After the pipeline is entirely coated by the fluid self-compaction quick-setting pouring medium, the top of the structure can directly spread the paving base layer and can be compacted by using a large-scale compacting machine.

In this embodiment, when the depth of the foundation pit cannot meet the requirement that the depth of the foundation pit exceeds 20 cm of the diameter of the pipeline due to the defects of insufficient thickness of the foundation bed and the like, the templates 15 are arranged on two sides above the foundation pit, and the fluid self-compaction rapid hardening filling medium is poured into the templates 15 of the supports, as shown in fig. 6, after the fluid self-compaction rapid hardening filling medium is solidified, a medium layer with sufficient thickness can be formed above the pipeline 4, so that the protection of the pipeline is completed, and the height of the templates on two sides above the foundation pit can be determined according to the depth of the foundation pit and the diameter of the pipeline, so that the thickness of the medium layer above the pipeline is ensured to be greater than 20 cm.

In summary, the backfill structure for pipeline construction can ensure the backfill compactness of all parts around the circular pipeline, particularly the backfill compactness in the wedge-shaped structural space at the bottom of the pipeline, and the pipeline is carefully protected, so that the excellent performance of the pipeline is fully exerted. Compared with backfill soil, the method has the advantages that the construction speed and the construction quality can be improved, and the method is favorable for expanding a mechanical working face during construction. Meanwhile, waste soil generated by excavating the foundation pit can be used as a raw material of a fluid self-compaction rapid hardening pouring medium, so that local material drawing is realized, the environment is protected, and the material cost and the construction cost can be reduced.

Claims

1. The utility model provides a backfill structure of pipeline construction which characterized in that: the pipeline (4) is paved at the pit bottom of the foundation pit (2) arranged on the surface of the rammed roadbed (1); the width of the foundation pit (2) is 10 cm larger than the outer diameter of the pipeline (4); the fluid self-compaction rapid hardening filling medium (5) is filled between the pipeline (4) and the inner wall of the foundation pit (2), and the top surface of the fluid self-compaction rapid hardening filling medium (5) is higher than the top of the pipeline (4).

2. The backfill structure for pipe construction of claim 1, wherein: the top of the foundation pit (2) is provided with a step-shaped groove (14).

3. The backfill structure for pipe construction of claim 1, wherein: the pit bottom of the foundation pit (2) is an arc-shaped surface.

4. The backfill structure for pipe construction of claim 1, wherein: when the pipeline (4) is paved at the pit bottom of the foundation pit (2), the height between the top opening of the foundation pit (2) and the top of the pipe is not less than 20 cm.

5. The backfill structure for pipe construction of claim 1, wherein: the pipeline (4) is formed by splicing a plurality of pipeline sections.

6. The backfill structure for pipe construction of claim 1, wherein: the fluid self-compaction quick-setting pouring medium (5) adopts cement soil or foaming concrete or concrete mortar.

7. The backfill structure for pipe construction of claim 1, wherein: cushion blocks for adjusting the straightness and levelness of the pipeline are paved at the shoulders and the bottoms of the left side and the right side of the pipeline.