Fluid soil backfilling lower pipeline anti-floating construction method based on temporary water filling in pipe

Abstract

The invention provides a fluid soil backfilling lower pipeline anti-floating construction method based on temporary water filling in a pipe, and belongs to the technical field of buried pipeline engineering construction. Comprising the steps that after a pipeline is laid stably, blocking plates, a water inlet facility and an exhaust facility are arranged at the two ends of the pipeline, clear water is injected into the pipeline, the overall self-weight of the pipeline is increased through the weight of water, and the sum of the self-weight of the pipeline and the weight of the water is not smaller than buoyancy before initial setting of fluid soil; meanwhile, gas in the pipe is exhausted through the exhaust facility until the water level reaches the preset volume or depth; after water injection is completed, fluid soil pouring and backfilling are conducted around the pipeline; and after the fluid soil is initially set and the strength reaches the construction standard, internal water is discharged through a water outlet of the pipeline or a closed water test is carried out. The method has the advantages of being easy and convenient to operate, low in cost and high in applicability, by calculating the water injection depth or volume, the anti-floating requirement can be met, water resource waste is avoided, and the construction efficiency and the engineering quality are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of buried pipeline engineering construction, in particular to a pipeline anti-floating construction method based on backfilling of fluidized soil with temporary water filling in the pipeline. Background Art

[0002] In the field of buried pipeline construction technology, fluidized soil, due to its excellent fluidity and compactness, can effectively fill the gaps between pipelines and foundation pits. In recent years, it has gradually been used in pipeline backfill construction. With the rapid development of domestic infrastructure, a large number of buried pipelines are backfilled with pumpable materials such as fluidized soil. However, the high fluidity of fluidized soil before initial setting creates an upward buoyancy force on the pipeline. The hollow pipeline is too light to resist this buoyancy, resulting in the pipeline easily floating during the backfill process, seriously affecting the pipeline's positioning accuracy and construction quality.

[0003] Existing technical solutions to prevent pipes from floating during backfilling with fluidized soil mainly involve measures such as installing temporary weights, anchoring pipes, or installing limiters. However, these methods suffer from complex construction, low efficiency, poor applicability, and high costs.

[0004] Based on this, developing a pipeline anti-floating construction method that is simple to operate, efficient and low-cost has important practical significance. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a pipeline anti-floating construction method under fluidized soil backfill based on temporary water filling in the pipe. By injecting clean water into the inside of the pipe, the weight of the water is used to increase the overall deadweight of the pipe, so that the sum of the deadweight of the pipe and the weight of the water is not less than the buoyancy of the fluidized soil before initial setting. This method does not rely on external weights or complex anchoring devices. It can adapt to pipes of different materials and diameters and fluidized soil backfill materials of different densities by simply controlling the amount of water injected. It has the advantages of simple operation, low cost and strong applicability. At the same time, by calculating the water injection depth or volume, it can meet the anti-floating requirements and avoid waste of water resources, thereby significantly improving construction efficiency and project quality.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A pipeline anti-floating construction method based on temporary water filling in the pipe under fluidized soil backfilling includes the following steps:

[0008] During the pipeline backfill construction process, after the pipeline is laid and stabilized, plugging plates, water inlet facilities, and exhaust facilities are installed at both ends of the pipeline. Clean water is injected into the pipeline through the water inlet and a water pump is used. At the same time, the gas in the pipeline is discharged through the exhaust facilities until the water level reaches a predetermined volume or depth.

[0009] According to the pipeline structural parameters, fluid soil density and buoyancy calculation results, the water injection depth is controlled so that the sum of the pipeline's own weight and the weight of the water in the pipe is not less than the buoyancy of the pipeline;

[0010] After the water injection is completed, the fluidized soil is poured backfill around the pipeline;

[0011] After the fluid soil has initially solidified and its strength reaches the construction standard, the internal water is discharged through the drain outlet of the pipe or a water-tightness test is carried out.

[0012] Preferably, the pipeline structural parameters include pipeline material, inner diameter, outer diameter and length.

[0013] Preferably, the anti-floating balance condition for controlling the water injection depth is:

[0014] F 浮 ≤G 管 +G 水 ;

[0015] Among them, F 浮 is the buoyancy force on the pipeline, G 管 is the weight of the pipeline itself, G 水 is the weight of water in the pipe.

[0016] Preferably, the buoyancy F exerted on the pipeline is 浮 The calculation formula is:

[0017]

[0018] Among them, γ f is the weight of fluidized soil, D 外 is the outer diameter of the pipe, L is the length of the pipe, V 排 The volume of fluid soil displaced by the pipe.

[0019] Preferably, the weight of the pipeline itself G 管 The calculation formula is:

[0020]

[0021] Among them, γ s The pipe material is heavy, D 内 is the inner diameter of the pipe.

[0022] Preferably, the weight of the water in the pipe G 水 The calculation formula is:

[0023] G 水 =γ w V;

[0024] Among them, γ w is the density of water, and V is the volume of water in the pipe.

[0025] Preferably, the calculation formula for the volume V of water in the pipeline is:

[0026]

[0027] Preferably, the water injection amount is controlled by measuring the water depth in the pipe, specifically including:

[0028] First, calculate the weight of the pipe when filled with water:

[0029]

[0030] Next, calculate the weight of water at any water level:

[0031]

[0032] Where θ is the arc angle calculated from the bottom of the pipe. The relationship between the arc angle θ and the water depth h is:

[0033]

[0034] Then the ratio k of water weight to full water at any water level is:

[0035]

[0036] Finally, the minimum ratio k and the corresponding water depth h are obtained by combining the anti-buoyancy balance conditions:

[0037]

[0038] Preferably, the blocking plate is Q235B or a welded steel plate with a strength grade not lower than Q235B, and is selectively welded according to construction requirements.

[0039] Preferably, the fluidized soil comprises foamed lightweight soil.

[0040] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0041] (1) The present invention temporarily fills the interior of the pipeline with water. It only needs to set up blocking plates, water inlet and exhaust facilities at both ends of the pipeline, and use a water filling pump to control the water injection volume to achieve anti-floating. There is no need to install complex external structures or invest in heavy equipment. The construction steps are simplified to three stages of "water injection-backfilling-drainage", which significantly reduces the amount of manual operation and construction time, while improving construction efficiency and safety.

[0042] (2) The present invention injects clean water into the interior of the pipeline, and uses the weight of the water to increase the overall deadweight of the pipeline, so that the sum of the deadweight of the pipeline and the weight of the water is not less than the buoyancy of the fluidized soil before initial setting. This method does not rely on external weights or complex anchoring devices, and can adapt to pipelines of different materials and diameters and fluidized soil backfill materials of different densities by simply controlling the amount of water injected. It has the advantages of simple operation, low cost, and strong applicability. At the same time, by calculating the depth or volume of water injection, it can meet the anti-floating requirements and avoid the waste of water resources, thereby significantly improving construction efficiency and project quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 This is a flow chart of a pipeline anti-floating construction method based on temporary water filling in the pipe and backfilling with fluidized soil according to the present invention;

[0045] Figure 2 The schematic diagram of the present invention provides a pipeline anti-floating construction method based on temporary water filling in the pipe and backfilling with fluidized soil; wherein, Figure 2 (a) is the principle diagram before backfilling of fluidized soil. Figure 2 (b) is the principle diagram of the pipe filling with water to prevent floating. Figure 2 (c) is the principle diagram of fluidized soil backfill. Figure 2 (d) is a diagram showing the drainage principle of flowing water after solidification. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 1 and Figure 2 As shown, the present invention provides a pipeline anti-floating construction method based on temporary water filling in the pipe and backfilling with fluidized soil, referring to Figure 2 (a) provides the principle diagram of fluidized soil before backfilling. Figure 2(b) provides a schematic diagram of the principle of anti-floating by filling the pipe with water. Figure 2 (c) in the figure provides a schematic diagram of the backfilling principle of fluidized soil. Figure 2 (d) provides a schematic diagram of the drainage principle of fluidized water after solidification. Specifically, the construction method includes the following steps:

[0049] Step 100: After the pipeline is laid and stabilized during the pipeline backfill construction process, baffles, water inlet facilities, and exhaust facilities are installed at both ends of the pipeline. Clean water is injected into the pipeline through the water inlet using a water filling pump, and the gas in the pipeline is discharged through the exhaust facilities until the water level reaches a predetermined volume or depth.

[0050] Step 200: Based on the pipeline structural parameters, fluid soil density, and buoyancy calculation results, the water injection depth is controlled so that the sum of the pipeline's own weight and the weight of the water in the pipeline is not less than the buoyancy applied to the pipeline.

[0051] Step 300: After the water injection is completed, the fluidized soil is poured backfill around the pipeline;

[0052] Step 400: After the fluidized soil has initially solidified and its strength reaches the construction standard, the internal water is discharged through the drainage port of the pipeline or a water-tightness test is performed.

[0053] According to the above content, the blocking plate is Q235B or welded steel plate with strength grade not lower than Q235B, and is selectively welded according to construction requirements. The fluidized soil uses foamed lightweight soil with low density as backfill material.

[0054] The pipeline structural parameters include pipeline material, inner diameter, outer diameter and length. Based on this, the process of controlling the water injection depth is as follows:

[0055] The anti-floating balance condition for controlling the water injection depth is determined as follows:

[0056] F 浮 ≤G 管 +G 水 ;

[0057] Among them, F 浮 is the buoyancy force on the pipeline, G 管 is the weight of the pipeline itself, G 水 is the weight of water in the pipe.

[0058] In the above-mentioned anti-buoyancy balance condition, the buoyancy force F on the pipeline is 浮 The calculation formula is:

[0059]

[0060] Among them, γ f is the weight of fluidized soil, D 外 is the outer diameter of the pipe, L is the length of the pipe, V排 The volume of fluid soil displaced by the pipe.

[0061] The pipeline's own weight G 管 The calculation formula is:

[0062]

[0063] Among them, γ s The pipe material is heavy, D 内 is the inner diameter of the pipe.

[0064] The weight of the water in the pipe G 水 The calculation formula is:

[0065] G 水 =γ w V;

[0066] Among them, γ w is the density of water, and V is the volume of water in the pipe.

[0067] The calculation formula for the volume V of water in the pipeline is:

[0068]

[0069] Based on the above, the water injection volume is controlled by measuring the water depth in the pipe. Specifically, the following steps are performed: First, the weight of the pipe filled with water is calculated:

[0070]

[0071] Next, calculate the weight of water at any water level:

[0072]

[0073] Where θ is the arc angle calculated from the bottom of the pipe. The relationship between the arc angle θ and the water depth h is:

[0074]

[0075] Then the ratio k of water weight to full water at any water level is:

[0076]

[0077] Finally, the minimum ratio k and the corresponding water depth h are obtained by combining the anti-buoyancy balance conditions:

[0078]

[0079] The above technical solution is further explained below through specific engineering cases.

[0080] Example 1

[0081] During the construction of a buried pipeline project, steel pipes are used for water transportation. The length of the pipeline is 1000m, and the inner diameter of the pipeline is D. 内 The pipe is 3m long and the pipe wall thickness t is 15mm. Then the outer diameter D of the pipe is 外 =3+2×0.015=3.03mm; at the same time, the weight of the steel pipe is γ s 78.5kN / m 3 , the fluidized soil is a foamy lightweight soil, and its gravity is γ f 8.0kN / m 3 , the water density γ w 9.81kN / m 3 .

[0082] In this embodiment, when anti-floating construction is first performed without using it, the buoyancy value of the pipeline is:

[0083]

[0084] Right now

[0085] The weight of the pipe itself is:

[0086]

[0087] Since the pipe is not filled with water, the anti-floating ratio is:

[0088]

[0089] From this, it can be found that the ratio of the gravity to the buoyancy of the pipeline is 0.19, which means that the gravity of the pipeline is much smaller than the buoyancy, and further indicates that anti-floating construction is needed.

[0090] At this point, if the pipe is filled with water, the weight of the pipe filled with water is:

[0091]

[0092] Assuming the pipe is filled with water, the anti-floating ratio is:

[0093]

[0094] If the anti-floating ratio is 1.4>1, it means that the pipe is completely filled with water, which has a good anti-floating effect. However, if the anti-floating ratio is greater than 1, it means that the pipe is filled with too much water, which is a waste of water resources. Therefore, it is necessary to control the amount of water filled. The minimum water volume and water depth inside the pipe that meet the anti-floating requirements are calculated:

[0095] Since the water filling in the above pipeline has met the anti-floating requirements, the minimum water filling volume inside the pipeline is:

[0096]

[0097] If the pipe is filled with water, the volume of the pipe filled with water is:

[0098]

[0099] Therefore, in this embodiment, by calculating the minimum water volume that meets the anti-floating requirements and comparing it with the full water volume, 2323m 3 water usage, thereby achieving the requirement of saving water.

[0100] For the minimum water depth that the pipeline meets the anti-floating requirements, the minimum proportional k value required for temporary water filling in the pipe must be guaranteed:

[0101]

[0102] Then substitute k=0.671 into:

[0103]

[0104] The obtained θ is 1.845, and then θ = 1.845 is substituted into:

[0105]

[0106] The result is h = 1.91m, that is, the water depth in the pipeline must be at least 1.91m to meet the anti-floating requirement, thereby achieving the demand of controlling the water inlet and ensuring water resource conservation.

[0107] Therefore, the above-mentioned anti-floating construction method for pipelines under fluidized soil backfill based on temporary water filling in the pipe is adopted. By injecting clean water into the pipeline, the weight of the water is used to increase the overall deadweight of the pipeline, so that the sum of the deadweight of the pipeline and the weight of the water is not less than the buoyancy of the fluidized soil before initial setting. This method does not rely on external weights or complex anchoring devices. It can adapt to pipelines of different materials and diameters and fluidized soil backfill materials of different densities by simply controlling the amount of water injected. It has the advantages of simple operation, low cost and strong applicability. At the same time, by calculating the water injection depth or volume, it can meet the anti-floating requirements and avoid water resource waste, thereby significantly improving construction efficiency and project quality.

[0108] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A pipeline anti-floating construction method based on temporary water filling in the pipe and backfilling with fluidized soil, characterized in that: The following steps are involved: During the pipeline backfill construction process, after the pipeline is laid and stabilized, plugging plates, water inlet facilities, and exhaust facilities are installed at both ends of the pipeline. Clean water is injected into the pipeline through the water inlet and a water pump is used. At the same time, the gas in the pipeline is discharged through the exhaust facilities until the water level reaches a predetermined volume or depth. According to the pipeline structural parameters, fluid soil density and buoyancy calculation results, the water injection depth is controlled so that the sum of the pipeline's own weight and the weight of the water in the pipe is not less than the buoyancy of the pipeline; After the water injection is completed, the fluidized soil is poured backfill around the pipeline; After the fluid soil has initially solidified and its strength reaches the construction standard, the internal water is discharged through the drain outlet of the pipe or a water-tightness test is carried out.

2. The method for anti-floating construction of pipelines based on temporary water filling in the pipeline by backfilling with fluidized soil according to claim 1, characterized in that: The pipeline structural parameters include pipeline material, inner diameter, outer diameter and length.

3. The method for anti-floating construction of pipelines based on temporary water filling in the pipeline by backfilling with fluidized soil according to claim 1, characterized in that: The anti-floating balance condition for controlling the water injection depth is: F 浮 ≤G 管 +G 水 ; Among them, F 浮 is the buoyancy force on the pipeline, G 管 is the weight of the pipeline itself, G 水 is the weight of water in the pipe.

4. The method for anti-floating construction of pipelines based on backfilling with fluidized soil by temporary water filling in the pipeline according to claim 3, characterized in that: The buoyancy F of the pipeline 浮 The calculation formula is: Among them, γ f is the weight of fluidized soil, D 外 is the outer diameter of the pipe, L is the length of the pipe, V 排 The volume of fluid soil displaced by the pipe.

5. The method for anti-floating construction of pipelines based on backfilling with fluidized soil by temporary water filling in the pipeline according to claim 4, characterized in that: The pipeline's own weight G 管 The calculation formula is: Among them, γ s The pipe material is heavy, D 内 is the inner diameter of the pipe.

6. The method for anti-floating construction of pipelines based on temporary water filling in the pipeline by backfilling with fluidized soil according to claim 5, characterized in that: The weight of the water in the pipe G 水 The calculation formula is: G 水 =c w ·V; Among them, γ w is the density of water, and V is the volume of water in the pipe.

7. The method for anti-floating construction of pipelines based on backfilling with fluidized soil by temporary water filling in the pipeline according to claim 6, characterized in that: The calculation formula for the volume V of water in the pipeline is:

8. The method for anti-floating construction of pipelines based on temporary water filling in the pipeline by backfilling with fluidized soil according to claim 7, characterized in that: The water injection volume is controlled by measuring the water depth in the pipe, including: First, calculate the weight of the pipe when filled with water: Next, calculate the weight of water at any water level: Where θ is the arc angle calculated from the bottom of the pipe. The relationship between the arc angle θ and the water depth h is: Then the ratio k of water weight to full water at any water level is: Finally, the minimum ratio k and the corresponding water depth h are obtained by combining the anti-buoyancy balance conditions:

9. The method for anti-floating construction of pipelines based on backfilling with fluidized soil by temporary water filling in the pipeline according to claim 1, characterized in that: The blocking plate is a welded steel plate made of Q235B or a strength grade not lower than Q235B, and is selectively welded according to construction requirements.

10. The method for anti-floating construction of pipelines based on backfilling with fluidized soil by temporary water filling in the pipeline according to claim 1, characterized in that: The fluidized soil includes foamed lightweight soil.

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