Method for Backfilling Self-Compacting Material of Pipeline

Abstract

The present invention relates to the field of pipeline engineering, and particularly relates to a method for backfilling a pipeline with self-compacting material, including: a pipeline installation step of leveling the bottom of a construction trench, placing a pipeline support formed by a first self-compacting material, and setting a pipeline on the pipeline support; a pipeline fixing step of arranging a plurality of fixing brackets formed by the first self-compacting material or the second self-compacting material at intervals in the length direction of the pipeline; a second self-compacting material pouring step of pouring the second self-compacting material into the construction trench where the pipeline is placed; wherein, the slump of the first self-compacting material is less than that of the second self-compacting material.

Description

Technical Field

[0001] The invention relates to the field of pipeline engineering, and in particular to a method for backfilling a pipeline with a self-compacting material. Background Art

[0002] Usually when laying pipelines, it is necessary to dig a construction trench, bury the pipeline in the construction trench, and then backfill the construction trench with materials. However, with the reduction of natural river sand resources, the price of high-quality medium-coarse sand materials that are easy to control quality has gradually increased, and the transportation distance for outsourcing is long. Therefore, in actual construction, local materials are often used for backfilling. As a result, the quality of backfilling is difficult to control, especially the backfilling materials obtained locally may contain large stones, which makes it impossible to compact the backfilling materials. As a result, after the pipeline construction is completed, the backfilling materials in the construction trench area settle, which brings safety hazards.

[0003] With the development of technology, the existing technology provides a self-compacting material. The self-compacting material has the characteristics of good fluidity. After the material is poured into the construction trench, it can rely on its own gravity to fill the construction trench and achieve the purpose of compacting the construction trench. After the self-compacting material solidifies, it has a certain strength and does not need to be compacted. Compared with traditional backfill materials, it is suitable for backfilling trenches of various drainage pipes. By adjusting the material ratio, the self-compacting material can meet the requirements of different construction periods, so it has been more and more widely used.

[0004] However, compared with traditional backfill materials, self-compacting materials are more likely to cause pipe floating during the backfill process, resulting in the problem of pipe installation position deviation.

[0005] Therefore, how to provide a method for backfilling a pipeline with a self-compacting material that can reduce the floating of the pipeline when the self-compacting material is backfilled, thereby improving the installation efficiency and accuracy of the pipeline, has become a problem that needs to be solved. Summary of the invention

[0006] In view of the problem that the floating of the pipeline during the backfilling of the self-compacting material in the prior art leads to a decrease in installation efficiency and accuracy, the present invention provides a method for backfilling the pipeline with the self-compacting material, comprising: a pipeline installation step, leveling the bottom of the construction trench, placing a pipeline support formed by a first self-compacting material, and setting the pipeline on the pipeline support; a pipeline fixing step, arranging a plurality of fixing brackets formed by the first self-compacting material or the second self-compacting material at intervals in the length direction of the pipeline; a second self-compacting material pouring step, pouring the second self-compacting material in the construction trench where the pipeline is placed; the slump of the first self-compacting material is less than the slump of the second self-compacting material.

[0007] According to the above technical solution, the first self-compacting material with low slump can be wrapped around the outside of the pipeline (i.e., forming a fixed support) to fix the pipeline and prevent the pipeline from floating. The distance between two adjacent fixed supports is determined by the diameter and weight of the pipeline (such as a PE pipe). It can be understood that due to the different diameters and weights of the pipelines, the buoyancy forces received by the pipelines in the second self-compacting material are different. For a PE pipe, the smaller the weight of the pipeline, the easier it is for the pipeline to float. Therefore, more pipeline supports are required to better fix the pipeline, and the distance between two adjacent pipeline supports is closer. Among them, the first self-compacting material can be a semi-dry material, and the second self-compacting material can be a liquid material.

[0008] Optionally, in the pipeline fixing step, the fixed support can be formed through a mold-making step, that is, first make a mold of the fixed support on the outside of the pipeline, then pour the first self-compacting material or the second self-compacting material into the mold. After the first self-compacting material or the second self-compacting material solidifies, remove the mold to obtain the fixed support formed by the first self-compacting material or the second self-compacting material.

[0009] Optionally, in the pipeline fixing step, the solid support can be formed by directly piling up the first self-compacting material on the outside of the pipeline. When piling up the first self-compacting material, it is preferably piled up in a way that gradually widens from bottom to top. The reason for adopting the above piling method is that although the slump of the first self-compacting material is very small, the first self-compacting material still has a certain slump. During the initial setting process, the upper part of the first self-compacting material will gradually slump to the lower part, and finally form a fixed support with a narrower upper part and a wider lower part. Adopting the above piling method can avoid excessive slumping of the first self-compacting material to the lower part of the pipeline during the initial setting process, resulting in a too narrow upper part and a too wide lower part of the fixed support, and ultimately reducing the ability of the fixed support to fix the pipeline.

[0010] Optionally, the second self-compacting material pouring step further includes: a layered height determination step, determining a first pouring value and a second pouring value according to the height of the construction trench and the installation height of the pipeline; a first pouring step, pouring and backfilling the construction trench, and stopping pouring when the height of the poured second self-compacting material reaches the first pouring value; a second pouring step, continuing to pour and backfill the construction trench after at least a part of the second self-compacting material poured in the first pouring step solidifies, and stopping pouring when the poured second self-compacting material reaches the second pouring value; a buoyancy judgment step, during the pouring of the second self-compacting material, comparing and judging the magnitude of the buoyancy force received by the pipeline with the self-weight of the pipeline in real time; a temperature control step, adjusting the temperature of the poured second self-compacting material according to the comparison result of the buoyancy judgment step.

[0011] According to the above technical solution, the first pouring value and the second pouring value are determined in advance according to the height of the construction trench and the installation height of the pipeline, so that the reasonable height of the second self-compacting material for pouring can be accurately determined. On the one hand, it does not provide excessive buoyancy to the pipeline to affect the pipeline connection. On the other hand, it does not pour a large amount of the second self-compacting material at one time, resulting in slow curing and affecting the construction efficiency. In the buoyancy judgment step, the magnitude of the buoyancy acting on the pipeline is compared with the self-weight of the pipeline to confirm whether the buoyancy acting on the pipeline at this time is within a suitable range. If the buoyancy is too large, the temperature control step needs to be entered. In the temperature control step, when the buoyancy acting on the pipeline is large, the temperature of the heat exchanger rises, increasing the curing speed of the second self-compacting material in some height regions, reducing the fluidity of the second self-compacting material, and thus reducing the buoyancy acting on the pipeline. This enables the self-compacting material backfilling method of the pipeline to reduce the floating problem of the pipeline during self-compacting material backfilling, thereby improving the installation efficiency and accuracy of the pipeline.

[0012] Optionally, it further includes a heat exchanger placement step, and according to the determined first pouring value, the arrangement height of the heat exchanger in the temperature control step is determined.

[0013] The heat exchanger is arranged at or near the liquid level. The good air permeability at the liquid level position can be utilized to quickly cure the second self-compacting material at the liquid level. The cured second self-compacting material can quickly fix the position of the pipeline. Moreover, the second self-compacting material cured by the heating method is more fluffy and has better air permeability, which can also take into account the curing efficiency of the uncured second self-compacting material below. On the other hand, only the second self-compacting material that is fluffy in part of the height does not affect the compactness of the overall backfill structure, ensuring the strength of the overall backfill structure.

[0014] Optionally, the second self-compacting material includes aggregate, cementitious material, admixture and water.

[0015] According to the above technical solution, the aggregate, cementitious material, admixture and water are uniformly mixed in a certain ratio to make it have certain fluidity, uniformity and stability. During the self-compacting material backfilling construction, it can flow and fill the construction trench under the action of gravity without external compaction, and can maintain a high compressive strength after curing.

[0016] Optionally, the pipeline support is provided with a density sensor, and in the buoyancy judgment step, the buoyancy acting on the pipeline is analyzed and calculated according to the density signal detected by the density sensor.

[0017] According to the above technical solution, according to the density signal detected by the density sensor, the buoyancy condition borne by the pipeline at this time can be calculated. The detection result of the density sensor is timely and accurate, which is beneficial to improving the accuracy of the calculation of the buoyancy acting on the pipeline.

[0018] Optionally, it further includes a counterweight anti-floating step of introducing liquid into the pipeline or uniformly arranging a plurality of counterweight parts along the pipeline.

[0019] According to the above technical solution, when it is found that the pipeline floats, by introducing liquid into the pipeline or uniformly arranging a plurality of counterweight parts along the upper part of the pipeline in the height direction, the gravity received by the pipeline is not less than the buoyancy received by itself, which is beneficial to keeping the pipeline stable during the pouring process.

[0020] Optionally, it further includes an earth compaction step of backfilling and compacting the construction trench with compacted soil and performing earth compaction treatment.

[0021] According to the above technical solution, after completing the pouring and backfilling of the construction trench with the second self-compacting material, after the second self-compacting material solidifies, the construction trench can be backfilled and compacted with compacted soil, and the compacted soil can be flattened through earth compaction treatment to restore the state before the construction trench was excavated and ensure the firmness and solidity of the ground.

[0022] Optionally, it further includes a height difference control step. During the pouring process, it needs to be carried out symmetrically, and the height difference between the two sides of the pipeline does not exceed the specified height difference.

[0023] According to the above technical solution, in order to ensure that during the pouring process, the pressures received by the pipeline from both sides are approximately the same, the pouring on both sides of the pipeline needs to be carried out symmetrically. The height difference between the two sides of the pipeline does not exceed the specified height difference, so that the pipeline will not be damaged or offset due to excessive pressure on one side, which is beneficial to ensuring the stability and accuracy of pipeline installation.

[0024] Optionally, in the temperature control step, the temperature of the heat exchanger is also adjusted according to the detection signal of the density sensor.

[0025] According to the above technical solution, the control unit adjusts the temperature of the heat exchanger according to the detection signal of the density sensor. After receiving the detection signal from the density sensor, the control unit analyzes and calculates the magnitude of the buoyancy received by the pipeline at this time. When the buoyancy received by the pipeline is large, the control unit will send a control signal to increase the temperature to the heat exchanger; when the buoyancy received by the pipeline is small, the control unit will choose to send a control signal to maintain the original state or decrease the temperature. Setting up the control unit can improve the accuracy of buoyancy analysis and calculation as well as temperature control, which is beneficial to improving the automation degree of the buoyancy judgment step and the temperature control step.

[0026] More specifically, according to the density of the second self-compacting material, the heating power of the heat exchanger is adjusted, which can take into account the energy consumption and the precise adjustment of the buoyancy magnitude, so that the buoyancy is always stable within a reasonable range where the pipeline will not float or can be stably connected by fasteners.

[0027] Optionally, it further includes the step of installing a density sensor. The density sensor is installed below the heat exchanger at a specified interval distance. By setting the density sensor below the heat exchanger at a specified interval distance, such as an interval distance of 10 - 30 cm, the curing state of the near liquid surface layer can be effectively monitored. When the near liquid surface layer has been completely cured or is close to being completely cured, it can timely remind to start the second pouring step, improving the construction efficiency.

[0028] Optionally, it further includes the following steps: when the density detected by the density sensor reaches the threshold value, stop the temperature control step and enter the second pouring step. As the water in the second self-compacting material evaporates, the density will change accordingly. By monitoring the curing state of the second self-compacting material according to the density, the comparison of buoyancy and the curing of the second self-compacting material in the near liquid surface layer can be considered simultaneously, and the second pouring step can be implemented in a timely manner, improving the construction efficiency.

[0029] Optionally, multiple density sensors are respectively installed at different height positions below the first pouring value. The density sensors installed at different height positions can reflect the density distribution of the second self-compacting material at different heights. On the one hand, it is convenient to understand the curing situation of the second self-compacting material in different height layers, and on the other hand, it can facilitate the calculation of the average density to obtain a more accurate buoyancy value, improving the accuracy of the comparison in the buoyancy judgment step.

[0030] Optionally, it further includes the following steps: in the step of placing the heat exchanger, the heat exchangers are centrally arranged horizontally within a specified height range. Centrally curing one or more layers within the specified height range can improve the curing time, save energy utilization, and at the same time, it does not affect the strength of the overall backfill structure. Description of the Drawings

[0031] Figure 1 is a flowchart of the method for backfilling self-compacting material for a pipeline in an embodiment of the present invention.

[0032] Figure 2 is a schematic diagram of the pipeline and the construction trench after the pipeline fixing step in an embodiment of the present invention.

[0033] Figure 3 is a three-dimensional schematic diagram of the pipeline after the pipeline fixing step in an embodiment of the present invention

[0034] Figure 4 is a flowchart of the second self-compacting material pouring step in an embodiment of the present invention.

[0035] Figure 5 is a schematic diagram of the pipeline and the construction trench after the second pouring step in an embodiment of the present invention.

[0036] Figure 6It is a module diagram of the control unit, density sensor, and heat exchanger according to an embodiment of the present invention.

[0037] Figure 7 It is a schematic diagram of the pipeline and construction trench after the soil compaction step according to an embodiment of the present invention.

[0038] Reference numerals: 100 pipeline; 200 construction trench; 1 pipeline support; 2 density sensor; 3 heat exchanger; 4 control unit; 5 counterweight; 10 base layer; 20 first casting layer; 30 second casting layer; 50 compacted soil layer; 60 fixed bracket; a height direction; L length direction. Specific embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] This embodiment provides a method for backfilling a pipeline 100 with self-compacting material. Figure 1 It is a flowchart of the method for backfilling a pipeline with self-compacting material according to an embodiment of the present invention. As Figure 1 shown, the method for backfilling a pipeline with self-compacting material includes: a pipeline installation step of leveling the bottom of the construction trench, placing a pipeline support 1 formed of a first self-compacting material, and setting the pipeline 100 on the pipeline support 1; a pipeline fixing step of fixedly arranging the pipeline 100 by spacing a plurality of fixed brackets 60 formed of the first self-compacting material in the length direction L ( Figure 3 shown), and a second self-compacting material pouring step of pouring the second self-compacting material into the construction trench 200 where the pipeline 100 is placed. And, the slump of the first self-compacting material is less than the slump of the second self-compacting material.

[0041] Figure 2 and Figure 3 It is a schematic diagram of the pipeline 100 and the construction trench 200 after the pipeline installation step and the pipeline fixing step according to an embodiment of the present invention. As Figure 3 and Figure 4As shown, in the pipeline installation step, the bottom of the construction trench 200 is leveled to form the base layer 10. After the leveling treatment is completed, the pipeline supports 1 are evenly placed on the base layer 10, and then the pipeline 100 is set on the pipeline supports 1. By forming the base layer 10 through the leveling treatment and setting the pipeline supports 1, the part supporting the pipeline 100 is firm and flat enough, which is beneficial to the stability during the installation of the pipeline 100 and facilitates the accurate determination of the subsequent first pouring value and second pouring value. The base layer 10 in this embodiment is a sand and gravel base layer 10. In some other embodiments of the present invention, it can also be a natural base layer 10 or a concrete base layer 10, etc.

[0042] In this embodiment, when setting the pipeline supports 1, it is necessary to pre-measure the hardness of the original soil where the pipeline 100 is located. If the hardness of the original soil is higher than the preset threshold, the pipeline supports 1 can be directly set on the surface of the original soil. Otherwise, the original soil is subjected to foundation treatment before proceeding to the next operation. When setting the pipeline supports 1, it is also necessary to re-level the qualified original soil to ensure uniform force on the pipeline 100.

[0043] The pipeline support 1 is preferably formed of a first self-compacting material. This can save the installation cost, improve the installation efficiency of the pipeline support 1, and is beneficial to the fixed cooperation between the first self-compacting material and the pipeline 100.

[0044] It should be noted here that Figure 2 and Figure 3 the construction trench 200 or the pipeline support 1 shown in Figure 3 are all schematic in nature and do not represent the specific structures of the actual construction trench 200 and the pipeline support 1. For example, the construction trench 200 is not limited to Figure 3 the vertical surface in

[0045] and can also be in the form of a slope surface.

[0045] In this embodiment, the fixing bracket 60 in the pipeline fixing step can be formed through the mold-making step. Specifically, first, a mold for the fixing bracket 60 is made outside the pipeline 100, and then the first self-compacting material is poured into the mold. After the first self-compacting material solidifies, the mold is removed, and the fixing bracket 60 formed of the first self-compacting material is obtained. In some other embodiments, the fixing bracket 60 can be formed by directly piling up the first self-compacting material outside the pipeline 100. When piling up the first self-compacting material, it is preferably carried out in a way that gradually widens from bottom to top. This is because, although the slump of the first self-compacting material is very small, the first self-compacting material still has a certain slump. During the initial setting process, the upper part of the first self-compacting material will slowly slump to the lower side, and finally a fixing bracket 60 with a uniform width from top to bottom is formed.

[0046] In an embodiment where the fixing bracket 60 is formed by a molding step, the fixing bracket 60 can also be made of a second self-compacting material. Without molding, it is not suitable to make the fixing bracket 60 from the second self-compacting material. Generally, the first self-compacting material is a semi-dry material, and the second self-compacting material is a liquid material. When using a mold to prepare the fixing bracket 60, the first self-compacting material or the second self-compacting material can be injected into the mold. Among them, since the first self-compacting material takes a shorter time to solidify, it is more conducive to quickly forming the fixing bracket 60.

[0047] As Figure 3 shown, the outer contour shape of the fixing bracket 60 is square to match the square construction trench 200. It can be understood that the outer contour shape of the fixing bracket 60 formed by piling up the first self-compacting material in the construction trench 200 tends to match the inner wall shape of the construction trench 200. However, in an embodiment where the fixing bracket 60 is formed by a molding step, the outer contour shape of the fixing bracket 60 can also be other shapes than square, for example, it can be circular.

[0048] Next, a more detailed description will be given of the self-compacting material and slump of this embodiment.

[0049] In this embodiment, the first self-compacting material and the second self-compacting material both include aggregate, cementitious material, admixture, and water. These materials are uniformly mixed in a certain ratio to make them have certain fluidity, uniformity, and stability.

[0050] The main components of the aggregate are construction waste soil and brick powder.

[0051] Among them, the construction waste soil is a type of construction waste. The construction waste soil obtained at the construction site is a coarse-grained soil mixed with soil and stone, including bricks, concrete fragments, and stones, etc. The main chemical components are silicate and calcium carbonate. The construction waste soil obtained at the construction site needs to be screened. Wood, plastic, fabric, alloy, and organic materials need to be removed. Especially for organic materials, because if the organic matter content is too high, it will seriously affect the curing effect of the gel material. Therefore, the content of organic matter in the construction waste soil should not exceed 4%. In addition, to ensure the uniformity of the material for pipeline backfill, the maximum particle size in the construction waste soil should not exceed 60 mm.

[0052] Among them, the brick powder is also a type of construction waste, mainly from the demolition of old buildings. Since most old buildings are brick-concrete structures, waste clay bricks account for a large proportion of the construction waste. Currently, the main treatment methods for waste clay bricks are simple landfill or open stacking, which not only pollute the environment but also occupy land. In fact, the brick powder is made of high-quality clay and has certain pozzolanic activity, with great potential for reuse.

[0053] It is worth mentioning that since the main component of brick powder includes SiO2, it can play a role in promoting the hydration reaction of cement. Under the action of the fine powder particles of brick powder, the same amount of cement can generate more calcium silicate hydrate (C-S-H gel), the efficiency of cement as a gel material is improved, the use of cement can be reduced, and it is beneficial to reduce costs.

[0054] The gel materials used are cement and fly ash.

[0055] Among them, preferably, the cement can be selected as PO42.5 portland cement. Its particle size distribution curve is measured by a laser diffraction particle size analyzer. In addition, adding fly ash to the cement can reduce the hydration reaction rate of the cement, which is beneficial to reducing the hydration heat. And the leaching rate of the cement mixed with fly ash in fresh water is significantly reduced. When it is used as a material for pipeline backfilling, it can improve the corrosion resistance of the pipeline backfilling material to groundwater.

[0056] The main function of the additive is to make the pipeline backfilling material have ideal fluidity, curing speed, frost resistance and other properties. Taking fluidity as an example, before adding the additive, the surfaces of the material particles carry opposite charges, resulting in an association effect between the particles. Therefore, nearly one-third of the water volume is wrapped in the particulate matter and cannot flow freely, thus affecting the fluidity of the pipeline backfilling material. After adding the additive, the surfaces of the material particles will all carry negative charges, forming an electrostatic repulsion effect, promoting the dispersion of the particulate matter, releasing the water volume originally wrapped in the particles, and enabling it to participate in the flow to improve the fluidity of the pipeline backfilling material.

[0057] The slump (spread) test is carried out according to the following standards:

[0058] 1. Moisten the slump cone and the base plate. There should be no free water on the inner wall and the base plate of the slump cone. The base plate should be placed on a firm and level surface, and the cone should be placed in the center of the base plate. Then step on the foot pedals on both sides with feet. The slump cone should be kept in a fixed position during loading.

[0059] 2. Evenly load the sample of the pipeline backfilling material obtained as required into the cone in three layers with a small shovel, so that the height of each layer after ramming is about one-third of the height of the cone. Each layer is rammed 25 times with a rammer. The ramming should be carried out from the outside to the center along a spiral direction, and each ramming should be evenly distributed on the cross-section. When ramming the pipeline backfilling material at the edge of the cone, the rammer can be slightly inclined. When ramming the bottom layer, the rammer should penetrate the entire depth. When ramming the second and top layers, the rammer should penetrate this layer to the surface of the next layer; when pouring the top layer, the pipeline backfilling material should be filled to a height higher than the cone opening. During the ramming process, if the pipeline backfilling material sinks below the cone opening, it should be added at any time. After the top layer is rammed, scrape off the excess pipeline backfilling material and level it with a trowel.

[0060] 3. After removing the materials for backfilling the pipeline on the bottom plate of the slump cone, lift the slump cone vertically and steadily. The lifting process of the slump cone should be completed within 5 - 10 s; the whole process from the start of loading to lifting the slump cone should be carried out continuously and should be completed within 150 s.

[0061] 4. After lifting the slump cone, measure the height difference between the height of the slump cone and the highest point of the test body of the materials for backfilling the pipeline after slumping, which is the slump value of the materials for backfilling the pipeline; after the slump cone is lifted, if the materials for backfilling the pipeline collapse or are damaged on one side, the sample should be taken again for measurement; if the above phenomena still occur in the second test, it means that the workability of the materials for backfilling the pipeline is not good and should be recorded for future reference.

[0062] 5. Observe the cohesion and water retention of the test body of the materials for backfilling the pipeline after slumping. The method for checking cohesion is to gently tap the side of the slump cone of the materials for backfilling the pipeline with a tamping rod. At this time, if the cone gradually sinks, it means that the cohesion is good; if the cone collapses, partially cracks or shows segregation, it means that the cohesion is not good. The water retention is evaluated by the degree of bleeding of the slurry of the mixture of the materials for backfilling the pipeline. If a large amount of slurry seeps out from the bottom after the slump cone is lifted and the aggregate of the materials for backfilling the pipeline in the cone part is exposed due to loss of slurry, it indicates that the water retention performance of this material for backfilling the pipeline is not good; if no slurry or only a small amount of slurry seeps out from the bottom after the slump cone is lifted, it means that the water retention of this mixture of the materials for backfilling the pipeline is good. When the slump of the mixture of the materials for backfilling the pipeline is greater than 220 mm, use a steel ruler to measure the final maximum diameter and minimum diameter after the expansion of the materials for backfilling the pipeline. Under the condition that the difference between these two diameters is less than 50 mm, use their arithmetic mean as the slump flow value; otherwise, this test is invalid.

[0063] The aggregate particle size of the first self - compacting material is larger than that of the second self - compacting material, and the content of water - reducing agent in the admixture used in the first self - compacting material is greater than that of the second self - compacting material. The larger particle size can reduce the water demand of the first self - compacting material, effectively reduce the water retention performance of the first self - compacting material, and improve the setting efficiency. And the reduction of the water content of the first self - compacting material can improve its plasticizing performance, reduce the slump of the first self - compacting material, so that the first self - compacting material shortens the setting working hours during the preparation of the pipeline support 1 and the fixation with the pipeline 100, speeds up the operation efficiency, and further improves the accuracy of fixing and positioning with the pipeline 100.

[0064] As an example, in this embodiment, the slump of the first self - compacting material is 0, and the slump of the second self - compacting material is 500.

[0065] Figure 4 It is the flow chart of the pouring step of the second self - compacting material in the embodiment of the present invention. As Figure 4As shown, in this embodiment, the second self-compacting material pouring step includes a first pouring step and a second pouring step. By pouring in two stages, the influence of buoyancy and the like can be reduced, thereby improving the pouring effect. Specific descriptions will be given below.

[0066] Figure 5 It is a schematic diagram of the pipeline 100 and the construction trench 200 after the completion of the second pouring step of the embodiment of the present invention. As Figure 5 shown, since the second self-compacting material is in a fluid state in the initial stage after pouring and cannot provide effective support for the pipeline 100 and will also generate buoyancy on the pipeline 100 before initial setting, a layered pouring method is adopted, and then the layered height determination step is entered. In the layered height determination step, according to the height of the construction trench 200 and the installation height of the pipeline 100, the first pouring value and the second pouring value are determined. Thus, the reasonable height of the second self-compacting material to be poured can be accurately determined. On the one hand, it does not provide too much buoyancy for the pipeline 100 to affect pipeline connection, and on the other hand, it does not pour too much second self-compacting material at one time, resulting in slow curing and affecting construction efficiency.

[0067] First, the first pouring step is started. In the first pouring step, the construction trench 200 is poured and backfilled to form a first pouring layer 20, and the pouring of the second self-compacting material stops when it reaches the first pouring value.

[0068] After the first pouring step is completed, the buoyancy judgment step is entered. In the buoyancy judgment step, the buoyancy received by the pipeline 100 is detected and analyzed. The pipeline 100 is fixed relative to the construction trench 200 through a fixed bracket 60 ( Figure 3 shown). To reduce the pressure on the fixed bracket 60 when the buoyancy received by the pipeline 100 is greater than its own gravity, further, a density sensor 2 is provided. According to the density signal detected by the density sensor 2, the buoyancy received by the pipeline 100 is analyzed and calculated. The density sensor 2 is a device for measuring the density of various solids, liquids, gases and mixtures. The detection result of the density sensor 2 is real-time and accurate, which is beneficial to improving the accuracy of the calculation of the buoyancy received by the pipeline 100. In addition, the position of the density sensor is not particularly limited, and it can also be set outside the pipeline to measure the density in a non-contact manner.

[0069] In this embodiment, by providing a control unit 4 communicatively connected to the density sensor 2 ( Figure 6The buoyancy is judged by (shown in) the density sensor 2. The specific judgment method is that the control unit 4 compares the density signal detected by the density sensor 2 with the actual weight of the pipeline 100, so as to obtain the information on the buoyancy condition borne by the pipeline 100 at this time. If the buoyancy condition is within the normal range (that is, the buoyancy will not cause the pipeline 100 to shift or float), there is no need to further perform the temperature control step. Otherwise, it is necessary to enter the temperature control step for further adjustment. Using density to calculate the pipeline buoyancy is a common calculation method, and the calculation formula etc. will not be elaborated here.

[0070] In some other embodiments of the present invention, the method for judging the buoyancy can also be to use a level sensor (not shown). By using the level sensor to detect whether there is tilt offset, the buoyancy condition of the pipeline 100 can be judged. This method can accurately detect the offset and floating of the pipeline 100 caused by too large buoyancy. It can also be the method of using human eye observation or distance sensor, which is not specifically limited here.

[0071] Furthermore, the method for backfilling the self-compacting material of the pipeline 100 further includes the heat exchanger placement step. According to the determined first pouring value, the layout height of the heat exchanger 3 in the temperature control step is determined. The heat exchanger 3 is arranged at or near the liquid level. By using the characteristic that the air permeability at the liquid level is better, the second self-compacting material at the liquid level can be quickly cured. The cured second self-compacting material can quickly fix the position of the pipeline 100. Moreover, the second self-compacting material cured by the heating method is more fluffy and has better air permeability, which can also take into account the curing efficiency of the second self-compacting material below that is not cured. On the other hand, only part of the second self-compacting material with high fluffiness does not affect the compactness of the overall backfill structure, ensuring the strength of the overall backfill structure.

[0072] In this embodiment, the heat exchangers 3 are centrally arranged horizontally within a specified height range. By centrally and quickly curing one or more layers within the specified height range, the curing time can be shortened, energy utilization can be saved, and at the same time, the strength of the overall backfill structure is not affected.

[0073] The heat exchanger 3 can adjust the temperature of the heat exchanger 3 according to the detection signal of the density sensor 2. By adjusting the heating power according to the density of the second self-compacting material, it is possible to balance the precise adjustment of energy consumption and buoyancy, so that the buoyancy is always stable within a reasonable range where the pipeline will not float or can be stably connected by fasteners. When the temperature rises, it will accelerate the solidification of the second self-compacting material, thereby reducing the fluidity of the second self-compacting material, and further causing the buoyancy received by the pipeline 100 to decrease. Conversely, when the temperature drops, it will slow down the solidification of the second self-compacting material, thereby reducing the fluidity of the second self-compacting material, and further causing the buoyancy received by the pipeline 100 to increase. Thus, by setting the heat exchanger 3 to adjust the temperature of the second self-compacting material, it is possible to change the buoyancy generated by the second self-compacting material on the pipeline 100, enabling construction personnel to adjust the buoyancy received by the pipeline 100.

[0074] Furthermore, the method for backfilling the self-compacting material of the pipeline 100 further includes a step of installing a density sensor. In this embodiment, the density sensor 2 is installed below the heat exchanger 3 at a specified interval distance. By setting the density sensor 2 below the heat exchanger 3 at a specified interval distance, usually an interval distance of 10 - 30 cm, it is possible to effectively monitor the curing state of the adjacent liquid surface layer. When the adjacent liquid surface layer has been completely cured or is close to being completely cured, it can timely remind to start the second pouring step, improving the construction efficiency.

[0075] In some other embodiments of the present invention, a plurality of density sensors 2 are respectively installed at different height positions below the first pouring value. The density sensors 2 installed at different height positions can reflect the density distribution of the second self-compacting material at different heights. On the one hand, it is convenient to understand the curing situation of the second self-compacting material in different height layers. On the other hand, it can facilitate the calculation of the average density to obtain a more accurate buoyancy value, improving the accuracy of comparison in the buoyancy judgment step.

[0076] Figure 7 It is a module diagram of the control unit 4, the density sensor 2, and the heat exchanger 3 in the embodiment of the present invention, as Figure 7As shown, the control unit 4 is communicatively connected to both the density sensor 2 and the heat exchanger 3. In the temperature control step S24, the control unit 4 adjusts the temperature of the heat exchanger 3 according to the detection signal of the density sensor 2. After receiving the detection signal from the density sensor 2, the control unit 4 analyzes and calculates the magnitude of the buoyancy force exerted on the pipeline 100 at this time. When the density detected by the density sensor 2 reaches the threshold value, the temperature control step is stopped and the second pouring step is entered. As the second self-compacting material evaporates water, its density will change. By monitoring the density to detect the curing state of the second self-compacting material, the comparison of buoyancy and the curing of the second self-compacting material near the liquid surface layer can be considered simultaneously, and the second pouring step can be implemented in a timely manner to improve the construction efficiency. When the buoyancy force exerted on the pipeline 100 is small, the control unit 4 will select to send a control signal to maintain the original state (i.e., the heat exchanger 3 does not heat the second self-compacting material) or reduce the temperature. Setting the control unit 4 can improve the accuracy of buoyancy analysis and calculation as well as temperature control, which is beneficial to improving the automation degree of the buoyancy judgment step S23 and the temperature control step S24.

[0077] In this embodiment, the control unit 4 is a PLC (Programmable Logic Controller). In some other embodiments of the present invention, the control unit 4 can also be in other forms, which are not specifically limited here.

[0078] The buoyancy judgment step S23 is not only a pre-step of the temperature control step S24. In this embodiment, the buoyancy judgment step S23 can also be a continuous step. During the operation of the temperature control step S24, the buoyancy judgment step S23 is also operating. Specifically, during the operation of the heat exchanger 3, the density sensor 2 is still detecting in real time. When the density sensor 2 detects that the buoyancy force exerted on the pipeline 100 is within the normal range, the control unit 4 will control the heat exchanger 3 to stop heating the second self-compacting material to avoid excessive solidification of the second self-compacting material, which is beneficial to ensuring a good pouring effect and reducing energy waste.

[0079] After the first pouring step is completed and the buoyancy judgment step confirms that the buoyancy force exerted on the pipeline 100 is within the normal range, the second pouring step can be started after at least a part of the second self-compacting material poured in the first pouring step has cured. In the second pouring step, the construction trench 200 is continuously poured and backfilled to form the second pouring layer 30, and the pouring stops when the poured second self-compacting material reaches the second pouring value.

[0080] After the second pouring step is completed, the buoyancy judgment step analyzes and judges the buoyancy situation of the pipeline 100 in the second pouring step. After confirming that the pipeline 100 is in a stable state, the heat exchanger 3 can be taken out. After the heat exchanger 3 is taken out, some holes will be left in the construction trench 200. Therefore, after the heat exchanger 3 is taken out, the second self-compacting material is used to fill these holes to ensure that the stability of the pipeline 100 is not affected.

[0081] When performing the buoyancy judgment step in the second pouring step, the standard value of the maximum buoyancy acting on the pipeline can be referred to. The standard value of the maximum buoyancy acting on the pipeline F fk (kN) is calculated by the formula F fk =γ sb V p , where γ sb is the apparent density (kN / m 3 ) during the pouring of the second self-compacting material. When the product confirmation value is missing, it can be calculated by taking the value of 20 kN / m 3 ; V p is the volume (m 3 ) of the pipeline immersed in the self-compacting backfill material. Compare the buoyancy acting on the pipeline 100 analyzed and calculated by the control unit 4 with the standard value of the maximum buoyancy acting on the pipeline F fk . If the buoyancy acting on the pipeline 100 at this time accounts for 70% of the standard value of the maximum buoyancy acting on the pipeline F fk , it can be considered that the buoyancy acting on the pipeline 100 is relatively large at this time, and the temperature control step S24 needs to be further carried out.

[0082] It should be noted that there should not be too long an interval between the first pouring step and the second pouring step.

[0083] In some other embodiments of the present invention, the layered pouring is not limited to two times, and can also be other more times. When the diameter of the pipeline 100 is relatively large, three times, four times, five times or more pourings can be carried out, and no specific limitation is made here.

[0084] In some other embodiments of the present invention, a space required for the installation of the heat exchanger 3 can be reserved in advance in the construction trench. This space can be made of a heat-conducting material. After the heat exchanger 3 completes the work of the first pouring step, it is removed from this space, and then the second self-compacting material is used to fill this space.

[0085] Furthermore, the method for backfilling the self-compacting material of the pipeline further includes a counterweight anti-floating step, and the counterweight anti-floating step can start during or after the first pouring step or the second pouring step. In this embodiment, the counterweight is applied when the first pouring layer 20 has solidified. First, a mold is made on the outer periphery of the pipeline 100, and a plurality of reserved spaces (not shown) are uniformly arranged along the pipeline 100 above the pipeline 100 in the height direction a, and the counterweight part 5 is arranged in each reserved space. Then, the second self-compacting material is poured. After the second self-compacting material solidifies, the outer mold of the pipeline 100 is removed, and the counterweight part 5 is removed. The setting of the counterweight part 5 makes the gravity received by the pipeline 100 during the pouring of the second self-compacting material not less than the buoyancy received by itself, which is beneficial to keeping the pipeline 100 stable during the pouring process.

[0086] In this embodiment, the counterweight part 5 is a sandbag. In some other embodiments of the present invention, the counterweight part 5 is not limited to a sandbag and can also be other forms of objects. The counterweight part 5 is not limited to being arranged above the pipeline 100 in the height direction a, and can also be arranged at other positions of the pipeline 100, which is not specifically limited here.

[0087] In other embodiments, the anti-floating effect can be further enhanced by the water injection method. Specifically: the first self-compacting material is poured. When the first self-compacting material is initially solidified, the pipeline 100 is placed, and the pipeline support 1 is used to prevent the pipeline 100 from shaking. Both ends of the pipeline 100 are closed and reserved holes are provided. The reserved holes can be opened or closed. A reserved well is arranged at a position of the first self-compacting material close to the pipeline 100. Water or other fluid substances are injected into the pipeline 100 through the reserved holes, and the second self-compacting material is poured. When the second self-compacting material is initially solidified, the water or other fluid substances in the pipeline 100 are discharged into the reserved well through the reserved holes. The fluid substances in the reserved well are removed, and the reserved well and the closures at both ends of the pipeline 100 are removed.

[0088] Figure 7 is a schematic diagram of the pipeline 100 and the construction trench 200 after the soil pressing step of the embodiment of the present invention is completed, as Figure 7 shown. Furthermore, the method for backfilling the self-compacting material of the pipeline further includes a soil pressing step. When the second pouring layer 30 poured in the second pouring step solidifies, the soil pressing step can start. In the soil pressing step, the construction trench 200 is backfilled with compacted soil, and the compacted soil is pressed and leveled to form a pressed soil layer 50 to restore the state before the construction trench 200 is excavated and ensure the stability and firmness of the ground.

[0089] Furthermore, the method for backfilling the self-compacting material of the pipeline further includes a height difference control step. To ensure that during the pouring process, the pressures exerted on both sides of the pipeline 100 are approximately the same, the pouring on both sides of the pipeline 100 needs to be carried out symmetrically. The height difference between the two sides of the pipeline 100 does not exceed the specified height difference, so that the pipeline 100 will not be damaged or displaced due to excessive pressure on one side, which is beneficial to ensuring the stability and accuracy of the installation of the pipeline 100. In this embodiment, the specified height difference is 10 cm. In some other embodiments of the present invention, the specified height difference can also be other values, which is related to factors such as the diameter of the pipeline 100. As the diameter of the pipeline 100 increases, the specified height difference also increases. As long as sufficient strength and stability requirements can be met, the specified height difference can also be appropriately increased.

[0090] Those skilled in the art can understand that the specific technical features in each embodiment can be adaptively split or combined. Such splitting or combination of specific technical features will not cause the technical solution to deviate from the principle of the present invention. Therefore, the technical solutions after splitting or combination will all fall within the protection scope of the present invention. In the description of this application, "a plurality of" means two or more, unless otherwise specifically defined.

[0091] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for backfilling self-compacting materials for pipelines, characterized in that, Including: Pipe installation steps: leveling the bottom of the construction trench, placing a pipe support formed by a first self-compacting material, and setting the pipe on the pipe support; Pipe fixing steps: arranging a plurality of fixing brackets formed by the first self-compacting material or the second self-compacting material at intervals in the length direction of the pipe; Second self-compacting material pouring steps: pouring the second self-compacting material into the construction trench where the pipe is placed; Wherein, the slump of the first self-compacting material is less than that of the second self-compacting material; The second self-compacting material pouring steps include: Stratification height determination steps: determining a first pouring value and a second pouring value according to the height of the construction trench and the setting height of the pipe; First pouring steps: pouring and backfilling the construction trench, and stopping pouring when the height of the poured second self-compacting material reaches the first pouring value; Second pouring steps: after at least a part of the second self-compacting material poured in the first pouring steps is cured, continuing to pour and backfill the construction trench, and stopping pouring when the height of the poured second self-compacting material reaches the second pouring value; Buoyancy judgment steps: during the pouring of the second self-compacting material, making a real-time comparison and judgment on the magnitude of the buoyancy received by the pipe and the self-weight of the pipe; Temperature control steps: adjusting the temperature of the poured second self-compacting material according to the comparison result of the buoyancy judgment steps; Heat exchanger placement steps: determining the layout height of the heat exchanger in the temperature control steps according to the determined first pouring value, and the heat exchanger is arranged at or near the liquid level; Counterweight anti-floating steps: introducing liquid into the pipe or arranging a plurality of counterweight parts uniformly along the pipe; A density sensor is arranged on the pipe support, and the buoyancy judgment steps analyze and calculate the buoyancy received by the pipe according to the density signal of the second self-compacting material detected by the density sensor; In the temperature control steps, the temperature of the heat exchanger is also adjusted according to the detection signal of the density sensor.

2. The method for backfilling self-compacting material of the pipeline according to claim 1, characterized in that, The second self-compacting material pouring steps further include: Soil pressing steps: backfilling and compacting the construction trench with compacted soil and performing soil pressing treatment.

3. The method for backfilling the self-compacting material of the pipeline according to claim 1, characterized in that, The second self-compacting material pouring steps further include: Density sensor installation steps: installing the density sensor at a specified interval distance below the heat exchanger.

4. The method for backfilling the self-compacting material of the pipeline according to claim 3, characterized in that The second self-compacting material pouring steps further include the following steps: when the density detected by the density sensor reaches the threshold value, stopping the temperature control steps and entering the second pouring steps.

5. The method for backfilling self-compacting material of a pipeline according to claim 1, characterized in that, A plurality of the density sensors are respectively installed at different height positions below the first pouring value.

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