Fast construction method for laying pipeline in narrow and long foundation pit under limited construction space

Abstract

The application provides a quick construction method for pipeline laying in a narrow foundation pit under a limited construction space condition, which comprises the following steps: S1, driving steel sheet piles on both sides of the narrow foundation pit, then excavating the narrow foundation pit, and building side walls of working wells at both ends of the foundation pit after the excavation of the narrow foundation pit is completed, then constructing steel enclosures and steel supports to form a foundation pit support system; S2, gradually laying and constructing from both ends of the narrow foundation pit to the middle part, until two remaining laying sections between the end laying sections of both ends are not subjected to pipeline laying construction; and S3, pipeline closing construction. The application solves the problem of low pipeline laying efficiency caused by the limited construction space during the pipeline laying construction in the narrow foundation pit.

Description

Technical Field

[0001] This invention belongs to the field of water supply and drainage construction technology, specifically relating to a rapid construction method for laying pipelines in narrow foundation pits under conditions of limited construction space. Background Technology

[0002] With the rapid development of urban construction in my country, infrastructure urgently needs improvement and perfection, leading to a surge in water supply, drainage, and sewage separation projects in recent years. Pipeline laying projects typically involve excavating a foundation pit, installing the pipeline, and then backfilling the pit. Open-cut construction is widely used in pipeline laying projects due to its simplicity and low cost; however, it has a significant impact on surrounding traffic and the environment. Pipelines are often laid under municipal roads, subject to traffic and surrounding buildings, resulting in limited construction sites and restricted working areas, making pipeline hoisting difficult. Furthermore, pipeline laying projects are linear projects, with narrow and long foundation pits, further restricting the working space for excavation, pipeline installation, and backfilling. Therefore, finding a rapid construction method for laying pipelines in narrow and long foundation pits has become a common challenge in the industry. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a rapid construction method for laying pipelines in narrow and long foundation pits under conditions of limited construction space, thus solving the problem of low pipeline laying efficiency caused by limited construction site space when laying pipelines in narrow and long foundation pits.

[0004] The present invention is achieved through the following technical solution.

[0005] A rapid construction method for laying pipelines in narrow pits under conditions of limited construction space is characterized by the following steps:

[0006] S1. Drive steel sheet piles into both sides of the narrow foundation pit, then excavate the narrow foundation pit. After the narrow foundation pit is excavated to the support position, construct steel walers and steel supports to form a foundation pit support system. Finally, after the narrow foundation pit is excavated to the predetermined position, construct the working well sidewalls at both ends of the foundation pit.

[0007] S2. Based on the length and weight of a single pipe section and the lifting radius of the truck crane, determine the laying length l of each pipe section. Then, divide the pipe into n sections according to the total length m and the laying length l of each section, satisfying m = (n-1) × l + k, where 0 < k ≤ l. Then, lay the pipe section by section from both ends of the narrow pit toward the middle with a length l, until there are two remaining sections between the last two sections that have not been laid. The lengths of the remaining two sections are l and k, respectively.

[0008] The specific steps of the segmented laying tool are as follows:

[0009] S21. Construction of the initial laying section:

[0010] (1) Pipeline hoisting and installation: A sand and gravel cushion layer is laid at the bottom of the narrow foundation pit in the initial laying section construction area, and the pipeline is hoisted and installed onto the sand and gravel cushion layer using a truck crane.

[0011] (2) Bottom retaining wall backfill: a permanent retaining wall is constructed at the bottom of the narrow pit at the end of the pipeline, and then medium and coarse sand is backfilled to the top of the permanent retaining wall.

[0012] (3) Backfilling of the middle retaining wall: Insert the lower temporary retaining member between the steel sheet piles on both sides of the narrow foundation pit, and make the bottom and top of the lower temporary retaining member connect with the top of the permanent retaining wall and the bottom of the steel waler respectively. Then backfill with medium and coarse sand and backfill soil to the top of the lower temporary retaining member.

[0013] (4) Backfilling of the top retaining wall: Remove the steel walers and steel supports, insert the upper temporary retaining wall between the steel sheet piles on both sides of the narrow foundation pit, and make the bottom and top of the upper temporary retaining wall connect with the top of the lower temporary retaining wall and the ground respectively. Then backfill with medium and coarse sand and backfill soil to the design elevation, and compact it to meet the design requirements to complete the initial section laying construction.

[0014] S22. Construction of the second laying section: Using the completed laying section as the working surface, the pipeline hoisting and installation, bottom retaining wall backfilling, middle retaining wall backfilling, and top retaining wall backfilling are completed sequentially using the same method as the initial laying section construction in step S21. Among them, after the bottom retaining wall backfilling, the upper and lower temporary retaining wall components installed in the previous laying section are pulled out in sequence to be used in the middle and top retaining wall backfilling processes of this laying section.

[0015] S23. Repeat step S22 to complete the construction of the subsequent laying sections in sequence until the last laying section is completed.

[0016] S3. Pipeline Closure Construction: Using the same method as the initial laying section construction in step S21, the laying sections that have been completed at both ends of the narrow and long foundation pit are used as the working surfaces. The remaining two laying sections are simultaneously hoisted and installed, and the bottom retaining wall is backfilled, the middle retaining wall is backfilled, and the top retaining wall is backfilled to close the pipeline. During the bottom retaining wall backfilling, no permanent retaining wall is constructed. After the bottom retaining wall backfilling, the upper and lower temporary retaining wall components installed in the last laying section are pulled out in sequence and are not used in the middle and top retaining wall backfilling processes of this laying section.

[0017] Preferably, in step S1, the narrow and elongated foundation pit is excavated using a segmented and layered open-cut method.

[0018] Preferably, in step S2, the laying length l of each section of the pipeline is the maximum value that satisfies the following conditions: l is an integer multiple of a single section of pipeline and is less than the maximum lifting radius of the truck crane.

[0019] Preferably, the pipe is a plastic-coated steel pipe, a concrete pipe, or a ductile iron pipe.

[0020] Preferably, the height of the permanent retaining wall is the same as the height of the laid pipeline.

[0021] Preferably, the permanent retaining wall is constructed of concrete masonry or sandbags.

[0022] Preferably, the upper and lower temporary retaining sections are assembled from steel plates and H-beams.

[0023] Preferably, both the upper and lower temporary retaining sections are provided with lifting holes on their top sides; the lower temporary retaining section is provided with a connecting joint on its top, and the bottom of the upper temporary retaining section is detachably inserted into the connecting joint.

[0024] Preferably, the butt joint is composed of triangular steel plates welded to both sides of the steel plate; 2 to 3 butt joints are provided, and the distance between adjacent butt joints is 1 to 1.5m.

[0025] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0026] (1) By constructing the pipeline in sections, the completed laying section can be used as the working surface for equipment such as truck cranes, excavators and road rollers to travel and operate on site, ensuring the continuity of pipeline installation and foundation pit backfilling, while improving the laying speed of the pipeline.

[0027] (2) This invention combines permanent and temporary methods, namely, constructing a permanent retaining wall and reusing the lower and upper temporary retaining components for backfilling the foundation pit. This not only ensures the safety of the foundation pit backfilling, but also reduces construction costs and improves construction efficiency, and provides conditions for the segmented laying of pipelines.

[0028] (3) The present invention adopts a method of laying the pipeline section by section from both ends of the narrow pit toward the middle, and finally closing the pipeline. This method can make full use of the narrow characteristics of the construction site and carry out parallel operations at the limited space at both ends of the pit, which effectively improves the laying efficiency of the pipeline.

[0029] In summary, this invention is ingenious in its concept, simple in its process, convenient and efficient, and solves the problem of low efficiency caused by limited construction site when laying pipelines in narrow and long foundation pits. It can provide a reference for future foundation pit excavation and pipeline laying in narrow and long sites, and has strong versatility, good social benefits and good prospects for promotion and application. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the main structure during the construction of a narrow and elongated foundation pit;

[0031] Figure 2 This is a top view during the construction of a narrow and long foundation pit;

[0032] Figure 3 This is a schematic diagram showing the construction process of laying the foundation stone section by section, moving from both ends of the narrow foundation pit towards the middle.

[0033] Figure 4 This is a schematic diagram of pipeline closure construction;

[0034] Figure 5 This is a schematic diagram of the construction of a permanent retaining wall during the initial laying section.

[0035] Figure 6 This is a cross-sectional view of the permanent retaining wall being constructed during the initial laying section.

[0036] Figure 7 This is a schematic diagram of the backfilling of medium-coarse sand during the initial laying section construction;

[0037] Figure 8 This is a schematic diagram of inserting the next temporary retaining member during the construction of the initial laying section;

[0038] Figure 9 This is a schematic diagram of the backfilling of medium-coarse sand and backfill soil during the initial laying section construction;

[0039] Figure 10 It is a cross-sectional view of the backfill medium-coarse sand and backfill soil during the initial laying section construction;

[0040] Figure 11 This is a schematic diagram of inserting a temporary retaining member from the upper section during the initial laying section construction;

[0041] Figure 12 This is a schematic diagram of the pipeline hoisting and installation during the construction of the second laying section;

[0042] Figure 13 This is a schematic diagram showing how the lower and upper temporary retaining sections of the initial laying section are pulled out during the construction of the second laying section so that they can be used in the middle and top retaining backfilling processes of the laying section, respectively.

[0043] Figure 14 This is a front view of the lower and upper temporary retaining sections;

[0044] Figure 15 This is the left view of the temporary retaining structure in the next section;

[0045] The meanings of the markings in the above diagrams are as follows: 1-Working well sidewall; 2-Steel sheet pile; 201-Steel waler; 202-Steel support; 3-Gravel cushion layer; 4-Steel pipe; 5-Permanent retaining wall; 6-Backfill layer; 7-Lower section temporary retaining component; 701-Steel plate; 702-H-beam; 703-Lifting hole; 704-Button joint; 8-Upper section temporary retaining component; 9-Truck crane; 10-Narrow foundation pit. Detailed Implementation

[0046] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0048] The present invention will be further described in detail below with reference to the accompanying drawings.

[0049] Example

[0050] For rapid construction methods of laying pipelines in narrow pits under conditions of limited construction space, please refer to [link to relevant documentation]. Figures 1 to 13 It includes the following steps:

[0051] S1, please refer to 1 and Figure 2 Steel sheet piles 2 are driven into both sides of the narrow and elongated foundation pit 10. Then, the narrow and elongated foundation pit is excavated using a segmented and layered open excavation method. After the narrow and elongated foundation pit 10 is excavated to the support erection position, steel walers 201 and steel supports 202 are constructed to form a foundation pit support system. Finally, after the narrow and elongated foundation pit 10 is excavated to the predetermined position, working well sidewalls 1 are constructed at both ends of the foundation pit. In this embodiment, the narrow and elongated foundation pit is 522m long, about 5m wide, and about 8m deep.

[0052] S2. During construction, truck cranes with the same performance are typically used to lift pipelines, and the length of each individual pipeline section is the same. Therefore, the laying length l of each pipeline section is the same. Based on the length and weight of a single pipeline section 4, and combined with the lifting radius of the truck crane 9, the laying length l of each pipeline section is determined. Then, based on the total pipeline length m and the laying length l of each section, it is divided into n segments to satisfy m = (n-1) × l + k, where 0 < k ≤ l. Afterwards, please refer to... Figure 3 and Figure 4The pipeline is laid in sections from both ends of the narrow pit toward the middle, with a length of l, until two sections remain between the last two sections that have not yet been laid. At this point, the number of sections that have been laid is n-2, and the lengths of the remaining two sections are l and k, respectively.

[0053] In this embodiment, the pipeline is a plastic-coated steel pipe with a diameter of 2.8m, a single section length of 6m, and a weight of approximately 12t. The truck crane has a capacity of 130t and a maximum lifting radius of 15m for lifting 12t pipeline sections. Since the length of each pipeline section to be laid should be an integer multiple of the length of a single section and should be less than the maximum lifting radius of the truck crane, and to ensure construction efficiency, the length of each pipeline section to be laid should also be as large as possible, under the above parameters of the pipeline and truck crane, the length of each pipeline section to be laid can be determined to be two sections, i.e., l = 12m. Since the long and narrow foundation pit is 522m long, i.e., the pipeline length is 522m, the entire pipeline can be divided into 44 sections for laying, of which 43 sections are 12m long, and the remaining section is 6m long, i.e., n = 44, k = 6m. Therefore, when the remaining two sections have not been laid, a total of 42 sections have been completed at both ends of the long and narrow foundation pit, and the remaining two sections are 12m and 6m long, respectively.

[0054] The specific steps of the segmented laying tool are as follows:

[0055] S21. Construction of the initial laying section:

[0056] (1) Pipeline hoisting and installation: Please refer to Figure 3 In the narrow foundation pit of the initial laying section, a sand and gravel cushion layer is laid at the bottom, and the pipeline is lifted and installed onto the sand and gravel cushion layer using a truck crane.

[0057] (2) Bottom retaining wall backfilling: Please refer to Figure 5-7 A permanent retaining wall 5 is constructed at the bottom of the narrow pit at the end of the pipeline, and then medium-coarse sand is backfilled to the top of the permanent retaining wall 5.

[0058] (3) Backfilling of the central retaining wall: Please refer to Figure 8-10 Insert the lower temporary retaining member 7 between the sheet piles 2 on both sides of the narrow foundation pit, and make the bottom and top of the lower temporary retaining member 7 connect with the top of the permanent retaining wall 5 and the bottom of the steel waler 201 respectively. Then backfill with medium and coarse sand and backfill soil to the top of the lower temporary retaining member 7.

[0059] (4) Backfilling of the top retaining wall: Please refer to Figure 11Remove the steel waler 201 and steel support 202, insert the upper temporary retaining member 8 between the steel sheet piles 2 on both sides of the narrow foundation pit, and make the bottom and top of the upper temporary retaining member 8 connect with the top of the lower temporary retaining member 7 and the ground respectively. Then backfill with medium and coarse sand and backfill soil to the design elevation, and compact it to meet the design requirements to complete the initial section laying construction.

[0060] S22. Construction of the second laying section: Please refer to... Figure 12 Using the completed laying section as the work surface, the pipeline hoisting and installation, bottom retaining wall backfilling, middle retaining wall backfilling, and top retaining wall backfilling are completed sequentially using the same method as the initial laying section construction in step S21; (Please refer to...) Figure 13 After the bottom retaining wall is backfilled, the upper temporary retaining wall 8 and the lower temporary retaining wall 7 installed on the previous laying section are pulled out in sequence to be used for the middle retaining wall backfilling and the top retaining wall backfilling process of the laying section.

[0061] S23. Repeat step S22 to complete the construction of the subsequent laying sections in sequence until the last laying section is completed.

[0062] In this embodiment, the permanent retaining wall 5 is constructed of concrete masonry; the retaining device should be prefabricated according to the width and depth of the narrow foundation pit, wherein the height of the upper temporary retaining member 8 is approximately 4m, and the height of the lower temporary retaining member 7 is approximately 1m; please refer to Figure 14 and Figure 15 The upper temporary retaining section 8 and the lower temporary retaining section 7 are assembled from 1cm thick steel plates 701 and H-beams 702. For ease of transportation and hoisting, the upper temporary retaining section 8 and the lower temporary retaining section 7 can be manufactured as a single piece or divided into multiple pieces. Both the upper temporary retaining section 8 and the lower temporary retaining section 7 have hoisting holes 703 on their top sides. Please refer to [link / reference]. Figure 14 and Figure 15 To facilitate the splicing of the upper and lower temporary retaining components, the top of the lower temporary retaining component 7 is provided with a butt joint 704, and the bottom of the upper temporary retaining component 8 is detachably inserted into the butt joint 704; two butt joints 704 are provided, and the spacing between the butt joints 704 is 1m.

[0063] S3. Pipeline closure construction: Using the same method as the initial laying section construction in step S21, the laying sections that have been completed at both ends of the narrow foundation pit are used as the working surfaces. The remaining two laying sections are simultaneously hoisted and installed, the bottom retaining wall is backfilled, the middle retaining wall is backfilled, and the top retaining wall is backfilled to close the pipeline.

[0064] Please refer to Figure 4When backfilling the bottom retaining wall, no permanent retaining wall 5 is constructed. After the bottom retaining wall is backfilled, the upper temporary retaining component 8 and the lower temporary retaining component 7 installed at the end of the laying section are pulled out in sequence and are not used for backfilling the middle of the remaining two laying sections. In the top retaining wall backfilling process, since only the two remaining laying sections have not been constructed, their total length is only l+k=18m, which is less than the sum of the maximum lifting radii of the two truck cranes. Therefore, the two truck cranes can be used to work synchronously at both ends to achieve the lifting and closure of the pipeline. At this time, the foundation pit of the remaining two laying sections can also be backfilled synchronously from both ends, and there is no need to construct a permanent retaining wall 5 or use the upper temporary retaining component 8 and the lower temporary retaining component 7 for retaining soil.

Claims

1. A rapid construction method for laying pipelines in narrow pits under conditions of limited construction space, characterized in that... Includes the following steps: S1. Drive steel sheet piles (2) into both sides of the narrow foundation pit (10), and then excavate the narrow foundation pit (10). After the narrow foundation pit (10) is excavated to the support position, construct steel walers (201) and steel supports (202) to form a foundation pit support system. Finally, after the narrow foundation pit (10) is excavated to the predetermined position, construct working well sidewalls (1) at both ends of the foundation pit. S2. Based on the length and weight of a single pipe section (4), and combined with the lifting radius of the truck crane (9), determine the laying length l of each section of the pipe. Then, based on the total length m of the pipe and the laying length l of each section, divide it into n sections to satisfy m=(n-1)×l+k, where 0<k≤l. Then, lay the pipe section by section from both ends of the narrow pit toward the middle with a length l, until there are two remaining sections between the last sections at both ends that have not been laid. The lengths of the remaining two sections are l and k, respectively. The specific steps of the segmented laying tool are as follows: S21. Construction of the initial laying section: (1) Pipeline hoisting and installation: A sand and gravel cushion layer is laid at the bottom of the narrow foundation pit in the initial laying section construction area, and the pipeline is hoisted and installed onto the sand and gravel cushion layer using a truck crane. (2) Backfilling of bottom retaining wall: a permanent retaining wall (5) is constructed at the bottom of the narrow pit at the end of the pipeline, and then medium and coarse sand is backfilled to the top of the permanent retaining wall (5). (3) Backfilling of the middle retaining wall: Insert the lower temporary retaining member (7) between the sheet piles (2) on both sides of the narrow foundation pit, and make the bottom and top of the lower temporary retaining member (7) correspond to the top of the permanent retaining wall (5) and the bottom of the steel waler (201) respectively. Then backfill with medium and coarse sand and backfill soil to the top of the lower temporary retaining member (7). (4) Backfilling of the top retaining wall: Remove the steel waler (201) and steel support (202), insert the upper temporary retaining member (8) between the steel sheet piles (2) on both sides of the narrow foundation pit, and make the bottom and top of the upper temporary retaining member (8) correspond to the top of the lower temporary retaining member (7) and the ground, respectively. Then backfill with medium and coarse sand and backfill soil to the design elevation, and compact it to meet the design requirements to complete the initial section laying construction. S22, Second laying section construction: Using the completed laying section as the working surface, the pipeline hoisting and installation, bottom retaining backfill, middle retaining backfill, and top retaining backfill are completed in sequence using the same method as the initial laying section construction in step S21; among them, after the bottom retaining backfill, the upper temporary retaining component (8) and the lower temporary retaining component (7) installed in the previous laying section are pulled out in sequence to be used in the middle retaining backfill and top retaining backfill of this laying section; S23. Repeat step S22 to complete the construction of the subsequent laying sections in sequence until the last laying section is completed. S3. Pipeline closure construction: Using the same method as the initial laying section construction in step S21, the laying sections that have been completed at both ends of the narrow foundation pit are used as the working surface. The remaining two laying sections are simultaneously hoisted and installed, and the bottom retaining wall is backfilled, the middle retaining wall is backfilled, and the top retaining wall is backfilled to close the pipeline. When backfilling the bottom retaining wall, no permanent retaining wall (5) is constructed. After the bottom retaining wall is backfilled, the upper temporary retaining wall (8) and the lower temporary retaining wall (7) installed in the last laying section are pulled out in sequence and are not used in the middle and top retaining wall backfilling processes of this laying section.

2. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 1, characterized in that, In step S1, the narrow and long foundation pit is excavated using a segmented and layered open-cut method.

3. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 1, characterized in that, In step S2, the laying length l of each section of the pipeline is the maximum value that satisfies the following conditions: l is an integer multiple of a single section of pipeline and is less than the maximum lifting radius of the truck crane.

4. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 1, characterized in that, The pipe (4) is a plastic-coated steel pipe, a concrete pipe, or a ductile iron pipe.

5. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 1, characterized in that, The height of the permanent retaining wall (5) is the same as the height of the laid pipe (4).

6. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 1, characterized in that, The permanent retaining wall (5) is constructed by concrete masonry or sandbag stacking.

7. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 1, characterized in that, The upper temporary retaining member (8) and the lower temporary retaining member (7) are assembled from steel plates (701) and H-beams (702).

8. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 7, characterized in that, The upper temporary retaining member (8) and the lower temporary retaining member (7) are provided with lifting holes (703) on both sides of the top; the lower temporary retaining member is provided with a butt joint (704) at the top, and the bottom of the upper temporary retaining member (8) is detachably inserted into the butt joint (704).

9. The rapid construction method for laying pipelines in narrow pits under confined construction space conditions as described in claim 8, characterized in that, The butt joint (704) is composed of triangular steel plates welded to both sides of the steel plate (701); 2 to 3 butt joints (704) are provided, and the distance between adjacent butt joints (704) is 1 to 1.5m.

Images