Internal pressure-resistant backfill injecting method for pipeline lining installation

Abstract

To improve the workability of backfill injection in lining installation where a rehabilitation pipe is inserted into a deteriorated existing pipeline, by resolving difficulties in managing the injection volume of cement milk and controlling the pressure of the backfill material that may cause deformation or damage to the lining pipe, cement milk is injected at a constant pressure into the annular space between the two pipes.SOLUTION: In a pipeline lining installation involving backfill injection, a lining pipe R is installed within an existing conduit P, and the upstream and downstream pipe ends of both the lining pipe R and an annular backfill space K are sealed; thereafter, a flowing water W from the upstream side is pressure-injected into the interior of the lining pipe R, while the injection pressure (internal pressure) of the water W is increased in conjunction with the injection pressure (external pressure) of a backfill material M, such that the backfill injection is performed under elevated pressure, and the discharge of the flowing water W through the lining pipe R is continuously maintained.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a backfilling construction method for lining work, which involves spirally winding a strip-shaped material continuously fed into a circular or rectangular cross-section culvert to form a circular cross-section lining pipe, and then pumping and injecting a backfilling material into the backfill space between the culvert and the lining pipe.In particular, the invention relates to a backfilling construction method for lining work that is suitable for application to small-diameter circular cross-section culverts and is further suitable for a head-push pipe making method performed using a head-push type pipe making machine. [Background technology]

[0002] In the so-called pipe lining construction, which involves inserting and installing a lining pipe into an existing pipe, backfill injection has traditionally been carried out, in which cement milk backfill material is injected into the backfill space between the existing pipe and the lining pipe. There are two methods for producing the lining pipes on site: the push-type method for circular cross-sections and small diameters, and the self-propelled method for rectangular cross-sections and medium to large diameters (pushing-type: a method in which the pipe is produced using a pipe production machine installed in a manhole and pushed into the sewer. Self-propelled method: a method in which the pipe production machine is installed inside the sewer, and the pipe is produced using the machine while also rotating and self-propelled). The following describes the injection of backfill material into a small diameter circular cross section pipe with a push-type backfill. The backfill material is injected at a constant pressure using an injection plant with a built-in injection pump, but the injection pressure must be within a range that will not cause buckling deformation of the lining pipe. When the lining section is short, the injection pressure is not high and the lining pipe does not deform, but when the lining section is long (for example, pipe diameter φ500mm, pipe length L20m), the injection pressure becomes high (for example, 10.0m head pressure), exceeding the allowable strength of the lining pipe. As a result, measures must be taken such as shortening the backfill length, increasing the water content of the cement milk, and lengthening the solidification period, which ultimately leads to a deterioration in workability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-126647 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above-mentioned circumstances, the present invention aims to improve the above-mentioned conventional backfill filling construction method and increase the backfill injection pressure, thereby making it possible to lengthen the lining and speed up the backfill injection, thereby improving the efficiency of lining construction. Therefore, the present invention was made based on the finding that this objective can be achieved by sealing pressurized water (called internal pressure) inside the lining pipe to counteract the injection pressure of the backfill material (backfill injection pressure), i.e., external pressure, which is a factor in the buckling deformation of the lining pipe, and using this internal pressure to counteract the external pressure, thereby eliminating the factor in the buckling deformation of the lining pipe. [Means for solving the problem]

[0005] The method of filling a backfill material against internal pressure in lining construction inside a sewer pipe of the present invention specifically employs the following configuration in order to achieve the above-mentioned object. (First invention) The first aspect of the present invention relates to a method for filling a backfill material against internal pressure in a lining construction inside a circular cross-section pipe, as described in claim 1, A method for lining a pipe with backfill injection, in which a strip-shaped member continuously fed out in a circular cross-section pipe is spirally wound to form a lining pipe with a circular cross-section, and a fluid backfill material is pressure-fed and injected into a backfill space between the pipe and the lining pipe, At the upstream and downstream pipe openings of the lining pipe, the lining pipe and the backfill space are sealed, respectively, while allowing a certain amount of discharge from the downstream side of the lining pipe; The flowing water from the upstream side is sealed and injected into the lining pipe with pressure, and the water injection pressure is made to counteract the increased backfill material injection pressure of the backfill material, and the flowing water through the lining pipe is continued. It is characterized by: (Second Invention) The second aspect of the present invention relates to a method for filling a backfill material against internal pressure in lining construction inside a rectangular cross section or a horseshoe cross section pipe, and as described in claim 2, A method for constructing a lining inside a pipe with a circular cross section is provided by spirally winding a strip-shaped member continuously fed into a pipe with a non-circular cross section such as a rectangular cross section or a horseshoe cross section to form a lining pipe with a circular cross section, and then injecting a fluid backfill material under pressure into a backfill space between the pipe and the lining pipe, At the upstream and downstream pipe openings of the lining pipe, the lining pipe and the backfill space are sealed, respectively, while allowing a certain amount of discharge from the downstream side of the lining pipe; The flowing water from the upstream side is sealed and injected into the lining pipe with pressure, and the water injection pressure is made to counteract the increased backfill material injection pressure of the backfill material, and the flowing water through the lining pipe is continued. It is characterized by: In the above, 1) "A certain amount of discharge" refers to the amount of water flowing that does not damage the sealed condition inside the lining pipe, and is achieved by appropriately adjusting the opening of the valve that allows the discharge.

[0006] (action) The lining pipe is sealed with an expanded, removable stop valve, and the downstream stop valve is equipped with a flow valve that can allow a certain amount of water to flow, and the backfill space is sealed on site using an adhesive sealant. The injection pressure of the backfill material is increased while the lining pipe is filled with water and within the range of the buckling limit pressure of the lining pipe. The pressure in the lining pipe is maintained until the backfill material solidifies. Even during the backfill injection work, a constant amount of water flows into the lining pipe from the upstream side and is discharged. [Effects of the Invention]

[0007] The injection pressure of the backfill material can be increased, which results in faster injection work and an increased injection volume, making backfill construction more efficient. Furthermore, it is possible to extend the length of lining construction. The water continues to flow even during backfilling work, so the progress of the lining work is not hindered. Furthermore, after the backfill material has solidified, compressive force (prestress) is introduced into the backfill material, strengthening the composite pipe that integrates the sewer, backfill layer, and lining pipe. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a construction procedure diagram showing a method for filling backfill material against internal pressure in the lining construction inside a sewer according to the present invention. [Figure 2] Cross-sectional view of a pipe during internal pressure counter-filling using this backfill material. [Figure 3] (a) is a front view of the stop valve (view taken in the direction of the arrow 3a in (b)), and (b) is a central cross-sectional view of the stop valve (cross-sectional view along line 3b-3b in (a)). [Figure 4] (a) Figure shows the structure of the upstream stop valve, and (b) Figure shows the structure of the downstream stop valve. [Figure 5] Diagram of the mechanism configuration at the top of the sealing section. [Figure 6] FIG. 1(a) is a cross-sectional view showing one embodiment of a belt-shaped member used in the present invention, and FIG. 1(b) is a cross-sectional view showing the joining relationship of this belt-shaped member. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the method for filling backfill material against internal pressure in lining work inside a sewer pipe according to the present invention will be described with reference to the drawings. 1 to 6 show an embodiment of the present invention, which shows a construction method for lining a pipe (also called a rehabilitation pipe) against internal pressure in a circular cross-section culvert. Furthermore, this embodiment shows a head-pushing type pipe making method in which a lining pipe is formed using a so-called head-pushing type pipe making device. 1 to 5 show the overall structure of the internal pressure resisting construction and the configuration of each part, and FIG. 6 shows one embodiment of a belt-shaped member used in the present invention. In these figures, P denotes a pipe with a circular cross section, and R denotes a lining pipe manufactured within the pipe P. W denotes a liquid (clean water, sewage, oil, etc.) flowing down the pipe P, and in this invention, sewage is taken. The direction of travel of the lining pipe R being manufactured within the sewer P is referred to as the front and rear.

[0010] The internal pressure resistance construction method for lining a sewer pipe according to the present invention is carried out in the following construction steps (1) to (5) in order. Strip-shaped member 100 (See Figure 6) Before explaining the internal pressure resistance construction method in the main sewer lining construction, we will explain the strip-shaped member used in the main sewer lining construction. FIG. 6 shows an example of a strip-shaped member that can be applied to the main sewer lining construction method of this embodiment. The belt-shaped member 100 has a flat plate-like body of a uniform thickness, and an appropriate number of ridges 102 (five in the illustrated example, usually three) are continuously provided vertically along the length of its outer surface. Flanges 102a are formed at the tips of the ridges 102. Grooves 104 or groove spaces are formed between the ridges 102. The inner surface 106 is formed to be substantially smooth. Joints 100A, 100B that overlap and engage with each other are formed on both sides of the belt-shaped member 100. That is, the leading edge side joint 100A has a protrusion 102A at its front end which has an expanded base and a vertical groove 110 extending from its inner surface, with a protrusion 112 continuing from the protrusion 102A. The trailing edge side joint 100B has a protrusion 114 extending from the protrusion 102B at its rear end, with a vertical protrusion 116 extending toward the end of the protrusion 114 which engages with the groove 110 of the leading edge side joint 100A. Furthermore, in this embodiment, a sealant 118 is interposed between the contacting portions of the protruding portions 112 and 114 to enhance sealing. The strip-shaped member is made of a synthetic resin material, and from the viewpoint of formability, polyvinyl chloride (PVC) resin is particularly suitable as it can be continuously molded by extrusion molding. During joining, the leading edge and trailing edge of adjacent strip-shaped members 100 overlap, and the leading edge joining portion 100A and the trailing edge joining portion 100B are sandwiched between the outer roller and inner roller of the joining roller unit (described later), so that the ridge 116 fits into the recessed groove 110, and the end of the protrusion 112 fits into the flange 102a of the protrusion 102B, and they are joined. In this case, the primary engagement is formed by the recessed groove 110 and the ridge 116, and the secondary engagement is formed by the protrusion 112 and the ridge 102B.

[0011] Process (1) Lining pipe installation (see Figure 1) Figure 1 shows the longitudinal cross-sectional structure of sewer pipe P during the filling work of backfill material in the middle of the lining work inside the main pipe, where Q1 is the upstream manhole, O1 is its opening, Q2 is the downstream manhole, O2 is its opening, and E is the ground where pipe P will be buried. In this construction work, construction will be carried out from the upstream manhole Q1 side towards the downstream manhole Q2 side. At the above-ground portion, a payout device (not shown) for the strip-shaped material 100 is installed on the upstream side, and the strip-shaped material 100 is continuously supplied by this payout device from the manhole opening O1 to a lining pipe making device (hereinafter simply referred to as the "pipe making device") installed in the manhole Q1. Furthermore, a hydraulic unit (not shown) is also arranged on the upstream side to supply pressurized oil to the pipe making device.

[0012] Process (1-1) Forming the lining pipe inside the sewer (see Figure 2) The pipe making device is carried in a disassembled state into the manhole Q1 upstream of the circular cross-section culvert P to be rehabilitated through the opening O1 of the manhole Q1, and the pipe making device is assembled inside the manhole Q1. Thereafter, the pipe making device is positioned toward the pipe mouth of the culvert P and is hydraulically driven to form the lining pipe R inside the culvert P. This pipe making device is a so-called push-type pipe making method, in which the strip-shaped member 100 that is continuously fed into the circular cross-section culvert P is spirally wound to form the lining pipe R with a circular cross-section. More specifically, the lining pipe R being formed is pushed into the circular cross-section culvert P while remaining in contact with the bottom surface of the culvert P, with a predetermined gap left above and to the sides. Figure 2 shows this state, with K indicating the gap between the circular cross-section culvert P and the circular cross-section lining pipe R, and this gap K forms the backfill space described later.

[0013] Process (2) Installation of stop valves (see Figures 1, 2, 3, and 4) After the lining pipe R is installed in the sewer P in a specified state and for a specified length (usually from the upstream manhole Q1 to the downstream manhole Q2), stop valves 10 (upstream stop valve 10A, downstream stop valve 10B) are fitted and installed at the upstream and downstream pipe openings of the lining pipe R while maintaining a seal (airtight and watertight) with the lining pipe R. When installing the stop valve 10, an air compressor 12 for the stop valve 10 is installed on the ground, and air pipes 13 connecting the air compressor 12 to the stop valves 10 (10A, 10B) are installed in the manholes Q (Q1, Q2) (see Figure 4). Furthermore, a water pump 16 and a pipe (for water supply) 17 are prepared for installation on the upstream side to be attached to the stop valve 10A, and a pipe (for water discharge) 18 is prepared for installation on the downstream side to be attached to the stop valve 10B. Insertion pipes 17a and 18a that are inserted into the central hole 10a of the stop valve 10 are attached to the ends of the water supply pipe 17 and the drainage pipe 18 via couplings H to the respective pipes 17 and 18. Control valves 17b and 18b are installed in the water supply and drainage pipes 17 and 18, respectively. The water supply control valve 17b prevents backflow of the sealed water W into the lining pipe R, and the drainage control valve 18b adjusts the amount of sealed water W discharged from the running pipe R.

[0014] (Stop valve 10) (See Figures 3 and 4) 3 and 4 show the detailed configuration of the stop valve 10. The stop valve 10 is a hollow cylindrical body made of rubber or cloth, has elasticity, and has a through hole 10a formed in the center, through which the insert pipes 17a, 18a of the above-mentioned piping 17, 18 are inserted while maintaining a tight seal. Compressed air is sent to the stop valve 10 (10A, 10B) from an air compressor 12 located on the ground through an air pipe 13, and by expanding the diameter of the pipe, the thick part 10b on the outer periphery is pressed against the inner surface of the lining pipe R, making tight contact, and also making tight contact with the pipes 17, 18, maintaining a tight seal with them. A bypass pipe 14 is attached to the upper part of the downstream stop valve 10B, and the bypass pipe 14 passes through the stop valve 10B and has a rising portion, in which a valve 14a is interposed (see FIG. 4).

[0015] Process (3) Sealing the backfill space (pipe opening sealing work) (see Figures 1 and 5) Next, as with the stop valve 10, sealing work, i.e., the formation of pipe opening seals 20 (upstream pipe opening seal 20A, downstream pipe opening seal 20B), is carried out in the gap (i.e., backfill space K) between the pipe P and the lining pipe R at the pipe openings on the upstream and downstream sides of the pipe P. In addition, for sealing the backfill layer, a cement milk injection plant 21 is installed above ground on the upstream side, and a pipe 22 (with a pressure gauge) is prepared inside the manhole Q1 to connect the injection plant 21 with the pipe mouth seal 20A. A valve 22a is installed in the pipe 22 to cut off the supply of cement milk from the injection plant 21.

[0016] Process (3-1) Initial work The pipe mouth seal 20 is made of clay cement (or quick-setting cement) material over a predetermined length (e.g., 50 mm) in the axial direction of the pipe around the entire circumference of the upstream and downstream pipe mouths. The material adheres to the inner surface of the pipe P and the outer surface of the lining pipe R, and over that predetermined length it maintains a high level of liquid-tightness against pressurized backfill material. An injection pipe 20a for injecting backfill material is attached to the upstream side (20A) through the top of the pipe mouth seal 20, and an air vent and overflow pipe (pipe) 20b for checking the overflow of backfill material is attached to the downstream side (20B). A piping 22 from the injection plant 21 described above is connected to the injection pipe 20a via a joint I, and a riser pipe 23 arranged to rise upward is connected to the air vent and overflow pipe (pipe) 20b also via a joint I. Furthermore, a drain hole (not shown) is provided in the downstream pipe mouth seal 20B as close to the pipe bottom as possible. The drain hole is for the purpose of pushing out the inflow water W that has accumulated in the gap between the culvert P and the lining pipe R with the backfill material that will be added later, and after it has been confirmed that the backfill material has been filled, the hole is sealed with quick-setting cement or the like. This is a natural consideration in the backfilling work, but is not an essential feature of the present invention.

[0017] Process (4) Internal pressure countermeasure work (backfilling work) After the completion of step (3), a series of operations are carried out to counteract the internal pressure, that is, to operate the water pump 16 and the cement milk injection plant 21 and continue to flow a constant amount of sewage W, while filling the backfill material by the pressure (internal pressure) inside the lining pipe R against the filling pressure (external pressure) of the backfill material. The internal pressure countermeasure work will be described in detail below in the order of steps.

[0018] Process (4-1) Sealing of lining pipes First, the water pump 16 is driven to send the sewage W in the upstream sewer into the lining pipe R until it is filled with water. That is, the drain valve 18b of the piping 18 downstream of the lining pipe R is opened (to maintain a discharge amount smaller than the discharge amount of the pump 16), and the lining pipe R is filled with water while some of the sewage W is discharged downstream. In this case, the upstream flowing water W continues to flow downstream. In this state, the water pump 16 is operating at a normal water pressure and is under a light load. At this time, the water pump 16 may operate at normal water pressure, but if the lining pipe R is to be filled with water quickly, the water pressure is increased and further increased to a head pressure of 2.0 to 3.0 m.

[0019] Process (4-1a) At this point, the injection plant 21 may be driven to start injecting the backfill material, i.e., cement milk M, but the injection pressure of this cement milk M (for example, a head pressure of 5.0 m) is set to be equal to or less than the empty strength of the lining pipe R (which varies depending on the pipe diameter, pipe length, and material). In other words, the injection of this backfill material M is not an injection against the internal pressure described below, but is a conventional normal injection, and the injection rate is also conventional, and is not an essential feature of the present invention. What is essential in the present invention is to carry out the below-described step (4-2) following the above step (4-1).

[0020] Process (4-2) Next, the injection plant 21 is driven to start injecting the initial backfill material, i.e., fluid cement milk M, into the backfill space K. That is, the valve 22a of the injection pipe 22 is opened, and the injection port pipe 20a in the pipe port seal 20 is opened. Meanwhile, the valve 23a of the downstream riser pipe 23 is opened, and the air vent and overflow pipe (pipe) 20b is opened. Then, the injection pressure (i.e., external pressure) of the injection plant 21 is increased to accelerate the injection rate of the backfilling material M, and the water supply pressure (i.e., internal pressure) of the water pump 16 into the lining pipe R, which is filled with water, is increased. At this time, as the pressure of the water pump 16 increases, the opening of the drain control valve 18b of the downstream drain pipe 18 is narrowed to continue the discharge of the flowing sewage W. Furthermore, the pressure sealed in the upstream and downstream stop valves 10 is increased to prevent the water from being drawn out.

[0021] Process (4-2a) Internal and external pressure adjustment operation The adjustment of the injection pressure by the injection plant 21 and the water supply pressure of the pump 16 is tolerable even if there is a slight difference (deviation) between the two pressures at the beginning of the injection of the cement milk M (head pressure 2.0 to 5.0 m), but the adjustment accuracy increases as the mortar injection pressure is increased. In other words, when the maximum filling mortar pressure reaches the maximum bearing capacity of the lining pipe R (for example, 20.0 m head pressure), the water supply pressure of the pump 16 is adjusted so as not to exceed this maximum bearing capacity. As a result, the lining pipe R does not undergo buckling deformation or breakage (the stop valve 10 is not pulled out at this time), and the mortar M is filled into the backfill space K in large quantities (large amounts) and quickly. At this time, the opening of the drain control valve 18a of the downstream stop valve 10B is adjusted appropriately, and the discharge of the sealed water W in the lining pipe R continues.

[0022] Process (4-4) End of backfill injection work and solidification of backfill material (1) After confirming that the backfilling material M being filled has fluidity and is overflowing from the riser pipe 23 of the downstream pipe opening seal 20B, the valve 23a of the riser pipe 23 is closed. Furthermore, the operation of the injection plant 21 is stopped, and the valve 22a of the injection pipe 22 is closed. Then, the piping portion above the inlet pipe 20a and the air vent / overflow pipe 20b of the pipe port seal 20 is removed. This marks the end of the backfill injection work. During this time, drainage from the drainage control valve 18b of the downstream stop valve 10B continues. (2) After this, the backfilling material M is allowed to solidify, and then the water pump 16 is stopped, and the supply of water to the lining pipe R is stopped. As the backfill material M solidifies, a compressive force (prestress) is introduced into the backfill material M.

[0023] Process (5) End of construction Once the solidification of the backfill material M is confirmed, the water supply control valve 17b of the upstream water supply pipe 17 is temporarily closed, and then the water supply pipe 17 upstream of the water supply control valve 17b, including the water supply pump 16, is removed. Next, the water level of the sealed water in the lining pipe R is lowered, and the downstream stop valve 10B and then the upstream stop valve 10A are removed in that order. This completes the construction work.

[0024] (Aspects of the embodiment) In the above-described embodiment, the stop valve 10 is in the form of a hollow rubber bag, but this does not prevent the use of other forms, such as 1) a solid rubber body that tightly fits tightly into the lining pipe R, or 2) a synthetic resin cap that similarly tightly fits into the lining pipe R. Furthermore, although the pipe opening seal 20 is made of clay cement on-site, it is also possible to use a ready-made synthetic resin cap that is fitted and fixed to the pipe opening.

[0025] (Effects of the embodiment) According to the method of filling backfill material against internal pressure in lining work inside a sewer pipe shown in this embodiment, the following special effects can be obtained. 1) A large injection pressure can be applied to the backfill material M, improving the workability of backfill injection work. In other words, rapid backfill injection work and an increase in the backfill length and therefore the lining length can be realized. 2) As the pressurized backfill material solidifies, compressive force (prestress) is introduced into the backfill layer, integrating the sewer P, backfill layer, and lining pipe, resulting in a composite pipe with great strength. 3) The downstream stop valve 10B can adjust its opening using its drainage control valve 18b to ensure that a constant amount of sewage flow is always discharged, even if the internal pressure of the lining pipe R increases.This allows the upstream flowing water to always flow downstream, allowing construction work to continue without interruption to the water supply.

[0026] The present invention is not limited to the above-described embodiment, and various design modifications are possible within the scope of the basic technical concept of the present invention. In other words, the following aspects are included within the technical scope of the present invention. 1) Regarding the culvert, in the previous embodiment, a circular cross-section lining pipe R is molded inside a circular cross-section pipe, but the present invention can also be applied to culverts with rectangular or horseshoe cross-sections. 2) In the previous embodiment, the lining pipe R was installed in a circular cross-section culvert by a push-type pipe making method, but in large cross-section culverts, the cross-section is rectangular or horseshoe-shaped. In this case, a lining pipe R of the desired shape can be formed using a self-propelled pipe-making device that uses a plastic strip-shaped member to form the lining pipe along a rectangular or horseshoe-shaped regulating frame, and the backfilling construction of the present invention can be applied to this lining pipe R. [Explanation of symbols]

[0027] P... culvert, Q... manhole, Q1... upstream manhole, Q2... downstream manhole, R... lining pipe (rehabilitation pipe), K... backfill space, M... backfill material (cement milk) 10...Stop valve, 10A...Upstream stop valve, 10B...Downstream stop valve, 10a...Center hole of stop valve, 12...Air compressor, 13...Air piping, 14...Air vent piping, 16...Water supply pump, 17...Water supply piping, 17a...Inlet pipe, 17b...Water supply control valve, 18...Drainage piping, 18a...Inlet pipe, 18b...Drainage control valve, 20...Pipe port seal, 20A...Upstream pipe port seal, 20B...Downstream pipe port seal, 20a...Inlet pipe, 20b...Air vent and overflow pipe, 21...Injection plant, 22...Injection pipe, 22a...Valve, 23...Rise pipe, 23a...Valve, 100... Belt-shaped member, 100A, 100B... Joint (joint)

Claims

1. A method for lining a pipe with backfill injection, in which a strip-shaped member continuously fed out in a circular cross-section pipe is spirally wound to form a lining pipe with a circular cross-section, and a fluid backfill material is pressure-fed and injected into a backfill space between the pipe and the lining pipe, At the upstream and downstream pipe openings of the lining pipe, the lining pipe and the backfill space are sealed, respectively, while allowing a certain amount of flowing water to be discharged from the downstream side of the lining pipe; The flowing water from the upstream side is sealed and injected into the lining pipe with pressure, and the water injection pressure is made to counteract the increased backfill material injection pressure of the backfill material, and the flowing water through the lining pipe is continued. A method for filling backfill material against internal pressure in lining construction inside a sewer pipe, characterized by:

2. A method for constructing a lining inside a pipe with a circular cross section is provided by spirally winding a strip-shaped member continuously fed into a pipe with a non-circular cross section such as a rectangular cross section or a horseshoe cross section to form a lining pipe with a circular cross section, and then injecting a fluid backfill material under pressure into a backfill space between the pipe and the lining pipe, At the upstream and downstream pipe openings of the lining pipe, the lining pipe and the backfill space are sealed, respectively, while allowing a certain amount of flowing water to be discharged from the downstream side of the lining pipe; The flowing water from the upstream side is sealed and injected into the lining pipe with pressure, and the water injection pressure is made to counteract the increased backfill material injection pressure of the backfill material, and the flowing water through the lining pipe is continued. A method for filling backfill material against internal pressure in lining construction inside a sewer pipe, characterized by:

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