JPH10281390A - Corrosion preventing coated steel pipe and its underground propulsive burying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a coating from being stripped, even by applying a propulsive burying method of a pipe. SOLUTION: A peripheral surface of two steel pipes 41 butt welding the fellow end parts by a welding bead part 33 is coated with a corrosion preventing first/second resin coating layer 32, 34. The first resin coating layer 32 is adhesively formed cylindrically in a welding part and a peripheral surface except in the vicinity thereof in the two steel pipes 41. The second resin coating layer 34, overlapped with an end part of the first resin coating layer 32 in both sides of the welding bead part, is adhesively formed cylindrically in a peripheral surface including the welding bead part 33. In one end part periphery of the second resin coating layer 34, a divided type cylindrical tightening metal fitting 42 fitted with a swollen part of the welding bead part 33 serving as the support part in a pipe axial direction is fitted, by this tightening metal fitting 42, an end part peripheral surface of the second resin coating layer 34 is retained. A tip end part of the tightening metal fitting 42 is formed in tapered shape in order to decrease earth pressure resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrosion prevention coated steel pipe applicable to an underground propulsion embedding method and an underground propulsion embedding method using the coated steel pipe.

[0002]

2. Description of the Related Art As a method of embedding a relatively small diameter pipe in the ground, a towed pipe propulsion embedding method is known. In this method, the expanding head is pulled and propelled by a pilot pipe underground,
The tube connected to the rear of the enlarged head is towed and propelled into the ground. The traction-type pipe propulsion burying method includes an earth-pumping type pipe propulsion burying method and a consolidation type pipe propulsion burying method. Here, the drainage pipe propulsion burying method will be described with reference to FIGS.

According to this method, the tip of a pipe 14 to be buried is inserted into a casing 11 extended to the rear of the enlarged head 7,
The tube 14 is held between the stopper 16 attached to the tip of the casing 11 and the enlarged head 7, and the casing 11 and the stopper 16 are held by the enlarged head 7 in this state.
And the rear end of the pipe 14 is
, Which is also disclosed in Japanese Patent Application No. Hei 2-213341 filed by the present applicant.

More specifically, as shown in FIG. 4A, a work start shaft 1 and a reaching shaft 2 are formed at both ends of an underground pipe section to be buried under a road or the like. With the hydraulic jack 4 installed, the pilot pipe 6 with the pilot head 5 at the head is pushed into the ground from the starting shaft 1 to the reaching shaft 2 to be propelled. Each time the pilot head 5 advances in the earth and sand 3 by one length of the pilot pipe 6, a new pilot pipe 6 is added, and the plurality of pilot pipes 6 are sequentially propelled like a scale.

When the pilot head 5 and the leading pilot tube 6 reach the reaching shaft 2, the jack propulsion operation of the jack 4 is stopped, and the pilot head 5 is detached from the leading pilot tube 6, and instead, as shown in FIG. An earth discharging type enlarged head 7 as shown in FIG.

After the connecting pipe 23 at the center of the enlarged head 7 is screwed to the pilot pipe 6, the distal end of the casing 11 is connected to the connecting pipe 23, and the distal end of the buried pipe 14 fitted from behind the casing 11. The part is inserted into the casing pipe 15. A support jig (not shown) for coaxially holding the casing 11 and the buried pipe 14 is disposed between the casing 11 and the buried pipe 14, and a stopper 16 is brought into contact with a rear end of the buried pipe 14, and the stopper 16 is directly attached to the casing 11. Removably attached to. Finally, a discharging screw 17 is placed in the casing 11,
Insert until the tip reaches the inside of the earth and sand inlet 13.

When the pipe pulling operation of the jack 4 is started in the state shown in FIG. 4B, the enlarged head 7 and the casing 11 are pulled by the pilot pipe 6, and the enlarged head 7 and the stopper 1 are pulled.
The buried pipe 14 held between 6 is pushed at its rear end by a stopper 16 and propelled underground. The earth and sand 3 under the ground are scraped into the earth and sand inlet 13 at the front end of the head body by the traction force of the expanding head 7 in the ground, and reach the earth discharging screw 17. By rotating the discharging screw 17 with the motor 18, the rubbed and introduced earth and sand 3 is sequentially transferred rearward by the discharging screw 17 and is removed to the outside from the rear end of the casing 11.

[0008]

Steel pipes are widely used for water and sewage pipes, gas pipes, oil transport pipes, various cable protection pipes, etc. buried underground. Asphalt and coal tar enamel coated steel pipes have been used for the outer peripheral surface of this steel pipe to strictly prevent corrosion, but in recent years, resin-coated steel pipes having even better corrosion resistance than these have become mainstream. . This resin-coated steel pipe is a steel pipe whose outer peripheral surface is continuously coated with a polyethylene resin or the like using an extruder and a round die.

However, when joining the end of a resin-coated steel pipe to another resin-coated steel pipe by welding, the temperature near the weld becomes high, so that the entire outer peripheral surface of the steel pipe including the end of the steel pipe is covered with resin from the beginning. If this is done, the resin coating layer at the end will melt under the influence of heat from welding. Therefore, as shown in FIG. 5A, the first resin coating layer 32 is formed on the outer peripheral surface of the steel pipe 31 except for the end.
Is formed in advance, and when welding is completed, a portion of the steel pipe 31 that is not yet covered including the weld bead portion 33 of the joint is covered with the second resin coating layer 34.

The first and second resin coating layers 32, 3
As the material for No. 4, for example, polyethylene having heat shrinkage is used. The first resin coating layer 32 is formed by applying molten polyethylene to the outer peripheral surface of a steel pipe before shipment at a factory using an extruder and a round die. The second resin coating layer 34 is formed by inserting a tubular body made of a polyethylene sheet slightly thicker than the outer diameter of the steel pipe into the outer periphery of the end of the steel pipe immediately before welding, and after an appropriate cooling time after the completion of welding, to the position of the welded part. Move the cylindrical body,
Thereafter, the cylindrical body is heated and shrunk by using a burner or the like, thereby forming a second resin coating layer in close contact with the welded portion of the steel pipe and the outer peripheral surface in the vicinity thereof.

When the joint portion of the steel pipe 31 is covered with the second resin coating layer 34 as shown in FIG. 5A, the second resin coating layer 34 is formed on the outer peripheral surface of the end of the first resin coating layer 32 as shown in FIG. Although the ends of the coating layer 34 overlap and the end of the first resin coating layer 32 is hidden, the end of the second resin coating layer 34 is exposed in a form riding on the end of the first resin coating layer 32. Will remain.

[0012] With the end of the second resin coating layer 34 exposed as described above, even if the coated steel pipe 31 welded by the pipe propulsion embedding method is to be buried and buried, the second resin coating layer 34 is to be buried.
Is easily turned up by violent friction with earth and sand, so that the second resin coating layer 34 as a whole is peeled off from this, and if the second resin coating layer 34 is peeled off, the first resin behind the second resin coating layer 34 is peeled off. As a result, the end of the coating layer 32 is also exposed in the earth and sand, so that the first resin coating layer 32 is also immediately peeled off from the end.

For this reason, conventionally, a corrosion-resistant resin-coated steel pipe 3
The propulsion burial method 1 was considered impossible with either the earth removal method or the consolidation method, and the steel pipe 31 welded by excavating the ground in a digging method was used. Also, conventional asphalt and coal tar enamel coated steel pipes are more vulnerable to friction with earth and sand than resin-coated steel pipes, so that the propulsion embedding method could not be applied similarly.

As described above, burying the steel pipe 31 by excavation requires a large amount of construction cost and construction period for excavation or backfilling with earth and sand. In addition, in places where there is a structure on the ground or construction space for excavation cannot be secured, There is a disadvantage that the digging work itself cannot be performed.

An object of the present invention is to provide a corrosion-prevention coated steel pipe to which a pipe propulsion burying method can be applied and a method of burying the steel pipe underground.

[0016]

In order to solve the above-mentioned problems, the corrosion-resistant coated steel pipe 31 of the present invention is composed of two steel pipes whose ends are welded to each other and a weld of the two steel pipes. A first resin coating layer for preventing corrosion formed in a cylindrical shape on the outer peripheral surface excluding the portion and the vicinity thereof, and an end portion of the first resin coating layer on both sides of a weld bead portion formed by the welding. A second resin coating layer for preventing corrosion formed in a cylindrical shape on the outer peripheral surface including the weld bead portion of the steel pipe, and a bulging portion of the weld bead portion on the outer periphery of one end of the second resin coating layer. And a split-type tubular fitting fitted as a support in the tube axis direction.

As described above, if the end of the second resin coating layer is covered with the fastener, the end of the second resin coating layer does not receive friction with earth and sand even when the pipe is propelled and buried, so that the second resin coating layer is not rubbed. There is no risk that the layers will peel off.

Further, since the fastener is fitted with the bulged portion of the weld bead portion as a support in the axial direction of the pipe, a large earth pressure in the axial direction of the pipe acts on the fastener as the pipe is propelled. Also, there is no possibility that the fastener is displaced.

Further, according to the present invention, the end of the fastener opposite to the weld bead portion is formed as a sharp tapered portion which is in close contact with the first resin coating layer, so that the earth pressure acting on the fastener in the pipe axis direction is reduced. Can be reduced, and the robustness or the thickness in the radial direction of the fastener can be made economical. Reducing the thickness of the fastener in the radial direction is advantageous in further reducing the influence of earth pressure in the pipe axis direction.

Further, the fastener used for the corrosion-resistant coated steel pipe of the present invention can be split in half in the radial direction, and the half face can be narrowed by a plurality of screws.

This makes it easier to attach the fastener to the end of the steel pipe, thereby improving work efficiency.

The fastener used in the corrosion-resistant coated steel pipe according to the present invention is divided into two parts in the axial direction of the pipe to form a first fastener and a second fastener, and the tapered portion is formed in the first fastener. The second fastener has a contact portion that contacts the weld bead portion, and the first and second fasteners are each capable of being split in half, and these half surfaces can be tightened by a plurality of screws. can do.

By dividing the fastener into the first and second parts as described above, the first fastener shares the function of holding down the end of the second resin coating layer, and the second fastener is The function of receiving the earth pressure acting on the first fastener is shared. The second fastener has a tendency to expand outward in the radial direction due to earth pressure support. However, by dividing the fastener in this way, the tendency of the second fastener to expand affects the first fastener. As a result, it is possible to prevent an adverse effect on the end pressing of the second resin coating layer.

The present invention also relates to a method of burying the above corrosion-resistant coated steel pipe in the ground by propelling and embedding a first resin coating layer for corrosion prevention in a cylindrical shape on the outer peripheral surface except for near both ends to be welded. Welding the formed two steel pipes by butt-welding the ends, and superposing the welded ends of the steel pipes on the ends of the first resin coating layer on both sides of the weld bead formed by the welding. Forming a second resin coating layer for preventing corrosion in a cylindrical shape on an uncoated outer peripheral surface of the tube; and forming a bulge portion of the weld bead portion on an outer periphery of one end of the second resin coating layer with a pipe shaft. A step of fitting a split-type cylindrical fastener as a supporting part in the direction, and a step of propelling and embedding the welded steel pipe in the ground, with the fastener as a front side and the weld bead part as a rear side. Having.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In addition, the present invention can be applied to both the earth discharging method and the consolidation method as long as it is a pipe propulsion burial method.

As shown in FIG. 1A, the corrosion-prevention coated steel pipe 41 according to the present invention is covered with a first resin coating layer 32 of polyethylene except for an end to be welded and its vicinity. The end of the steel pipe is joined by welding to the other end of the steel pipe in an abutting state, and the end of the steel pipe including the welded portion is covered with the second resin coating layer 34. Both ends of the second resin coating layer 34 overlap each other so as to ride on the outer peripheral surface of the end of the first resin coating layer 32. The above structure is the same as that of the conventional corrosion-resistant coated steel pipe 31 described with reference to FIG.

The corrosion prevention coated steel pipe 41 of the present invention is different from the conventional one in that a fastener 42 is fitted on one side of a weld bead portion formed by welding, that is, on the outer peripheral surface of the end of the steel pipe on the side of the pipe in the propulsion direction. That is the point. The metal fitting 42 has a cylindrical surface, and the second resin coating layer 3
4 covers an area reaching the first resin coating layer 32 beyond the end. As shown in FIG. 1B, the fastener 42 includes a first fastener 42a having a tapered tip 43 and a second fastener 42b whose rear end is supported by the weld bead 33. . Each of the fasteners 42a and 42b is shown in FIGS.
As shown in (1), a split mold that can be split into two in the radial direction is formed. The length of these bolts 43 is such that their heads are hidden in the recesses 51 formed on the outer peripheral surface of the fastener 42 after the tightening is completed. This can prevent the head of the bolt 43 from becoming an earth pressure resistance. First fastener 42a
There are two front and rear fastening bolts 43, but the two front and rear fastening bolts 43 of the second fastener 42b are two intermediate bolts in total. Thus the second
The reason why the number of the fastening bolts 43 of the fastener 42b is increased is that a large earth pressure acting on the first fastener 42a is reliably supported by the second fastener 42b.

The distal end portion 43 of the first fastener 42a is designed to prevent the earth pressure accompanying the propulsion of the coated steel pipe 41 from being directly received from the front.
The tapered shape is as sharp as possible as long as the required strength is satisfied. A butyl rubber layer 44 is provided between the sharp tip 43 and the first resin coating layer 32, and has a structure for preventing intrusion of earth and sand from this portion. First
A shallow concave portion 45 equivalent to the thickness of the second resin coating layer 34 is formed on the inner peripheral surface of the fastener 42a, and the second resin coating layer 3 riding on the end of the first resin coating layer 32 is formed in the concave portion 45.
4 are housed. In this way, the second
The first fitting 42 accommodates the end of the resin coating layer 34.
The inner peripheral surface at the tip end of the butyl rubber layer 44 is made as strong as possible.
This is for crimping. That is, when there is no concave portion 45, the tightening force of the first fastener 42a acts intensively on the end of the second resin coating layer 34, and the first fastener 42a with respect to the first resin coating layer 32 to the butyl rubber layer 44. This weakens the crimping force of the inner peripheral surface of the distal end portion 43. On the inner peripheral surface of the concave portion 45, an annular ridge 46 having a continuous cross section of a triangular ridge having a small cross section is provided.
Are formed continuously, and the ridges 46 bite into the outer peripheral surface of the second resin coating layer 34 with an appropriate depth. This allows the second
The end of the resin coating layer 34 and the first fastener 42a are integrated. In addition, it is preferable that the two bolts 43 of the first fastener 42a are arranged on both sides of the concave portion. Thus, the tightening force of the first fastener can be effectively applied as a pressing force between the inner peripheral surfaces on the front end side and the rear end side.

The rear end of the first clamp 42a and the second clamp 4
At the front end of 2b, steps 47 and 48 having an L-shaped cross section are formed in an annular shape so that they can be fitted to each other. The rear end of the second fastener 42b is further provided with a concave part having a quarter-arc cross section so that it can be fitted to one half of a bulging part having a semi-circular cross section radially outward of the weld bead part 33. 49 is formed in an annular shape. From the rear end of the first clamp 42a to the rear end of the second clamp 42b, a number of streaks 50 similar to the streaks 46 described above are continuously provided. The inner peripheral surface of the rear end of the metal fitting 42a and the entire inner peripheral surface of the second metal fitting 42b are appropriately bite and integrated.

The corrosion prevention coated steel pipe 41 according to the present invention is constituted as described above, and this coated steel pipe 41 is buried in the ground by the steps described below with reference to FIG. Here, the buried pipe 14 in FIG. 4 is to be read as the coated steel pipe 41 of the present invention. First, as shown in FIG. 4 (A), the starting shaft 1 and the reaching shaft 2 are excavated at both ends of the planned route of burying the steel pipe 41. Then, the jack 4 is carried into the start shaft 1 and the jack 4
The pilot pipe 6 with the pilot head 5 at the head is pushed into the ground from the starting shaft 1 to the reaching shaft 2 by using. Each time the pilot head 5 moves forward in the earth and sand 3 by one length of the pilot pipe 6, a new pilot pipe 6 is added, and the plurality of pilot pipes 6 are sequentially propelled in the shape of a scale.

When the pilot head 5 and the leading pilot pipe 6 reach the reaching shaft 2, the jack propulsion operation of the jack 4 is stopped, the pilot head 5 is detached from the leading pilot pipe 6, and FIG. Is connected to the leading end of the pilot tube 6 at the head.

The connecting pipe 2 of the enlarged head 7 is connected to the pilot pipe 6.
After screwing 3, the distal end of the casing 11 is connected to the connecting pipe 23, and the distal end of the coated steel pipe 41 inserted from behind the casing 11 is inserted into the casing pipe 15. A support jig (not shown) for holding the both coaxially is arranged between the casing 11 and the coated steel pipe 41, and the stopper 16 is brought into contact with the rear end of the coated steel pipe 41, and the stopper 1 is kept as it is.
6 is removably attached to the casing 11. Finally, the earth discharging screw 17 is inserted into the casing 11 until the tip of the screw 17 reaches the inside of the earth and sand inlet (not shown) of the enlarged head 7.

When the pipe pulling operation of the jack 4 is started in the state shown in FIG. 4B, the enlarged head 7 and the casing 11 are directly pulled by the pilot pipe 6 and are held between the enlarged head 7 and the stopper 16. The coated steel pipe 41 is the stopper 1
It is pushed by 6 to propel underground. The earth and sand 3 under the ground are raked into the earth and sand inlet 13 at the front end of the head body by the traction force of the enlarged head 7 in the ground, and reach the earth discharging screw 17. Then, the earth discharging screw 17 is rotated by the motor 18, so that the rubbed and introduced earth and sand 3 are sequentially transferred rearward by the earth discharging screw 17, and are removed to the outside from the rear end of the casing 11.

At the stage when the first coated steel pipe 41 has been substantially propelled into the ground, the stopper 16 is once removed, and the outer periphery of the rear end of the first coated steel pipe 41 or the outer circumference of the front end of the second coated steel pipe 41 is removed. A cylindrical body (not shown) of a polyethylene sheet to be the second resin coating layer is inserted. In order to advance the first coated steel pipe 41 as much as possible,
It is better to insert this cylindrical body around the outer periphery of the front end of the second coated steel pipe 41. After inserting the cylindrical body that becomes the second resin coating layer 34 into the end of the coated steel pipe in this manner, the cylindrical body is moved to a position slightly away from the end of the coated steel pipe, and the first and second coated steel pipes 41 are formed. The ends are welded in abutting condition. When the heat of welding has cooled down appropriately, the cylinder is moved in the direction of the welded portion, so that the middle part of the cylinder coincides with the weld bead part 33 of FIG. 1 formed by welding. At this time, the both ends of the cylinder are
One end of the resin coating layer 32, that is, one coated steel pipe 41
The end of the first resin coating layer 32 on the rear end side and the end of the first resin coating layer 32 on the front end side of the second coated steel pipe 41 are overlapped by a predetermined length. Thereafter, the outer periphery of the cylindrical body is heated by a heating means such as a burner, and the cylindrical body is thermally contracted to form a weld bead portion 3.
The second resin coating layer 34 is formed by bringing the cylindrical body into close contact with the uncoated outer peripheral surface of the end of the steel pipe including No. 3.

Next, the second fastener 42b is mounted on the outer peripheral surface of the end of the steel pipe in a state where the concave portion 49 at the rear end is in contact with the weld bead portion 33, and the four bolts 43 are sequentially tightened to divide the second fastener 42b. Tighten the mold. Thereafter, the first metal fitting 42a is mounted on the outer peripheral surface of the steel pipe end in a state where the step 47 at the rear end of the first metal fitting 42a is in contact with the step 48 at the front end of the second metal fitting 42b.
The bolts 43 are sequentially tightened to dye the split mold. After that, the stopper 4 is applied to the rear end of the second coated steel pipe 41 in the same manner as in the conventional embedding and embedding method, the jack 4 is operated, and the first and second coated steel pipes 41 are integrally propelled. By repeating the above steps, the coated steel pipe 41
To the ground one after another. At this time, since the front end of the second resin coating layer 34 of each coated steel pipe 41 is covered and fastened by the fastener 42 of the present invention, it is not turned up by friction with earth and sand. Even if the rear end of the second resin coating layer 34 is exposed in the ground, it does not turn over in relation to the propulsion direction.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible. Although the example in which the coated steel pipe 41 of the present invention is propelled and buried is shown, the coated steel pipe 41 of the present invention can be sufficiently propelled and buried even if the steel pipe has a relatively small diameter by a pipe propulsion burying method which is not an earth removal type. Also, the fastener 4 of the present invention
Although it is practical to make 2 divided into two in the radial direction, when the diameter of the coated steel pipe is larger than a certain degree, it may be possible to improve the workability rather than dividing it into three or more.

[0037]

As described above, according to the present invention, since the front end of the exposed second resin coating layer of the conventional coated steel pipe is covered with the fastener, the second resin coating layer is turned up by friction with earth and sand. The embedding work by the underground propulsion of the coated steel pipe which has been impossible in the past can be made technically practical. In addition, since the fastener used in the present invention uses the bulge of the weld bead portion of the steel pipe as the support part in the pipe axis direction, a large earth pressure acts on the fastener in the pipe axis direction with the promotion of the coated steel pipe. Even so, there is no danger that the fastener will be displaced by this earth pressure. Furthermore, by adopting a structure in which the fastener is divided into two parts, a first fastener on the front side and a second fastener on the rear side, the earth pressure in the pipe axis direction accompanying the propulsion of the pipe is reduced by the second fastener. It is possible to handle the holding of the second resin coating layer by the first fastener, and to prevent the tendency of the second fastener to expand in the radial direction due to the earth pressure support in the pipe axial direction from reaching the first fastener. Thus, regardless of the magnitude of the earth pressure in the pipe axis direction, the front end of the second resin coating layer can be stably and reliably pressed and held by the first fastener.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a welded portion of a coated steel pipe according to the present invention, and FIG. 1B is a cross-sectional view of a fastener of the present invention.

FIG. 2A is a sectional view of a first fastener, and FIG. 2B is an end view of the same.

3A is a sectional view of a second fastener, and FIG. 3B is an end view thereof.

FIG. 4A is an underground cross-sectional view in a pilot pipe propulsion step of a conventional burial method, and FIG. 4B is an underground cross-sectional view in a pilot pipe pulling step of the same method.

FIG. 5A is an external perspective view of a conventional corrosion-resistant coated steel pipe, and FIG. 5B is a cross-sectional view of a welded portion.

[Explanation of symbols]

 41 Corrosion prevention coated steel pipe 42 Clamp 42a First clamp 42b Second clamp 43 Bolt 45 Recess 47,48 Step 49 Recess

Claims (5)

[Claims] 1. Two steel pipes whose ends are welded to each other in abutting condition, and a corrosion-preventing corrosion prevention formed in a cylindrical shape on an outer peripheral surface excluding a welded portion of the two steel pipes and the vicinity thereof. Corrosion formed in a cylindrical shape on the outer peripheral surface including the weld bead portion of the steel pipe by superimposing on the first resin coating layer and the ends of the first resin cover layer on both sides of the weld bead portion formed by the welding. A second resin coating layer for prevention, and a split-type tubular fastener fitted around an outer periphery of one end of the second resin coating layer with a bulge portion of the weld bead portion as a support portion in a tube axis direction. A corrosion-resistant coated steel pipe, characterized by having: 2. An anti-corrosion coated steel pipe according to claim 1, wherein an end of said fastener opposite to said weld bead portion is a sharp tapered portion which is in close contact with said first resin coating layer. . 3. The fastener is capable of being split in half in a radial direction.
2. The fastener according to claim 1, wherein said half surface can be narrowed by a plurality of screws. 4. The first metal fitting is divided into two parts in a pipe axis direction, and
A fastener and a second fastener, wherein the first fastener has the tapered portion, the second fastener has a contact portion abutting on the weld bead portion, and the first and second fasteners have a tapered portion. 2
2. The fastener for a corrosion-resistant coated steel pipe according to claim 1, wherein each of the fasteners can be split in half, and the half face can be tightened by a plurality of screws. 5. A step of welding two steel pipes having a first resin coating layer for preventing corrosion, which are formed in a cylindrical shape on the outer peripheral surface except for the vicinity of both ends to be welded, at the ends thereof. And a second resin coating layer for preventing corrosion is placed on the uncoated outer peripheral surface of the welded end of the steel pipe so as to overlap the ends of the first resin coating layer on both sides of the weld bead portion formed by the welding. A step of forming a tube-shaped close contact, and fitting a split-type cylindrical clamp having a bulged portion of the weld bead portion as a support portion in the tube axis direction around an outer periphery of one end of the second resin coating layer. Underground propulsion of a corrosion-resistant coated steel pipe, comprising the steps of: propelling and embedding the welded steel pipe in the ground with the fastener being on the front side and the weld bead part being on the rear side. Burying method.