JP2003278149A - Water stopping method for steel sheet-pile joint part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a water stopping joint having more severe water stopping performance by fitting and driving a male joint of a post-driven steel sheet-pile while securing large adhesive property and stickiness of steel material and filling material required for water stopping performance in a fitting joint part of the steel sheet-pile. <P>SOLUTION: In this water stopping method for a joint part, while a pair of fitting joints are fitted to each other through a water stopping filling material, steel sheet-piles such as a steel sheet-pile and steel pipe sheet-pile are driven. The method is characterized in that in pre-driven steel sheet-pile, visco- elastic material 11 composed mainly of asphalt is previously filled as a water stopping filling material in a space of a pre-driven joint steel pipe 8a having a slit 7, the pre-driven steel sheet-pile is driven in a designated place of ground, and subsequently, when a T-joint 10 of a post-driven steel sheet-pile is inserted in the joint steel pipe 8a filled with the visco-elastic material 11, the post-driven steel sheet-pile is inserted and driven while vibration with a designated frequency or higher frequency or fixed shock is applied to the pile. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water-blocking revetment work,
The present invention relates to improvement of a water stopping method in a joint structure of steel sheet piles such as steel sheet piles and steel pipe sheet piles used for landfill construction and levee construction work.

[0002]

2. Description of the Related Art Conventionally, steel sheet piles such as steel sheet piles and steel pipe sheet piles are used for water-impervious revetment work, land reclamation work, levee construction work, etc., but especially steel sheet pile walls are industrial waste or general waste. When used as a water-blocking revetment structure for landfills where landfills are disposed of at sea, it is strictly required to prevent water from leaching from the landfill to the open sea through the fitting joints of steel sheet piles. Has been done.

That is, in general, when constructing a sea surface landfill disposal site, a seawall is constructed along the planned boundary line of the sea surface landfill site to create a landfill disposal site which is shielded from the open sea, and waste is disposed in this disposal site. Had been dumped. Steel sheet piles such as steel sheet piles and steel pipe sheet piles are used as this type of revetment.

When constructing a sea surface reclamation revetment using steel sheet piles such as steel sheet piles and steel pipe sheet piles, important points to keep in mind are that the contaminated water in the landfill disposal site is the bottom of the revetment, the sheet pile joints, etc. How to prevent leaching from the sea to the open sea.

For example, as shown in FIG. 12, steel pipe sheet piles 1 are formed in a water-blocking wall shape along the boundary of the sea surface landfill site 4.
It is connected and arranged via a joint part 2 made up of a male joint 2a and a female joint 2b, which are provided on the side surfaces of the respective symmetrical parts by fitting in the up-down direction, and one joint between the main pipe 1a of the steel pipe sheet pile 1 and the sheet piles. In the hollow portion 9 of the portion (female joint 2b in the figure),
A water blocking material 3 such as a mortar or an asphalt mixture is filled, and the water blocking material 3 is configured to prevent the water held in the disposal site 4 from leaching into the open sea through the joint portion 2.

In a conventional steel pipe sheet pile, the male joint has a T-shape, and the female joint has a shape for forming a circular or square pocket having a slit for fitting in the vertical direction (PT). Type) and a joint (PP type) of a type in which circular joint steel pipes having slits are fitted to each other for both male and female joints.

As a method of stopping water at the joint, a steel pipe sheet pile or the like is driven into the ground, and then the sand and sand that have entered the filling pocket of the water blocking filler of the fitting joint at the time of driving is water jetted. After washing, the pocket is generally filled with a filler such as a mortar or an asphalt mixture for stopping water.

[0008]

However, it is very difficult to completely remove the earth and sand that once entered the pocket portion by a water jet, etc. Even if the invading earth and sand is once removed, it is filled after cleaning. The earth and sand again invade the slit portion of the fitting joint before the material is filled, so that the residual earth and sand may be bitten into the filler or the quality of the filler may be deteriorated. This tendency is remarkable at the bottom of the joint and the mortar joint. There is a problem that the water-stopping performance is deteriorated because the part where the sand and sand remain and the part where the predetermined mortar quality is not obtained are weak points in the water-stopping.

As a method for preventing the intrusion of earth and sand from such a slit, Japanese Utility Model Laid-Open No. 7-29017 and Japanese Unexamined Patent Application Publication No. H9-29107.
No. 78569 discloses a method of attaching a sand intrusion plate or a sand intrusion prevention tape, but the earth and sand intrusion plate / tape may come off when the pre-strike steel sheet pile is sunk, or There is a problem that workability deteriorates.

Further, in Japanese Unexamined Patent Publication No. 10-102483, a rod-shaped filler made of expanded polystyrene or expanded vinylidene is pre-filled in the pocket portion of the female joint when the pre-strike steel sheet pile is sunk, and the post-strike is performed. A method of fitting and placing a male joint of a steel sheet pile so as to cut and compress a rod-shaped body is disclosed, but the polystyrene foam and the vinylidene foam itself do not have sufficient waterproofness in the long term, and the filler and steel Has poor adhesion and adhesion, and has no fluidity,
Once a water channel is formed at the interface between the steel material and the filler during casting, almost no waterproofness can be expected.

Japanese Unexamined Patent Publication (Kokai) No. 52-121907 discloses a method of using a filler composed mainly of atactic polypropylene as the filler, to which heavy oil and a butane-gen rubber solution are added. Atactic Polypropylene is a paste-like or wax-like substance, and its adhesiveness is not so strong that it can be pushed in to cut the male joint of a post-punched steel sheet pile, and has long-term fluidity at room temperature. It has a certain degree of self-closing property, and is said to be suitable for forming a water-stop joint.

On the other hand, in order to secure the waterproof property and to add the adhesive force, straight asphalt and heavy oil are added, and in order to further increase the adhesive force, a butadiene rubber solution is added. As shown. However, since the main component of this is atactic polypropylene, the adhesive force and adhesive force are generally weak, and the resistance at the time of driving is reduced, but the adhesive force and adhesive force for securing water stoppage are not enough. After the joint is formed, if the joint is bent or deformed, or if a tensile force acts and the joint is deformed in the separating direction, the adhesive force or the adhesive force is not sufficient, so there is a gap between the joint and the filler. There will be a gap, which will become a water leak and cause water leakage. Therefore, there is a problem that sufficient water-stop performance cannot be ensured in situations where high water-stop performance is required. Further, atactic polypropylene has a drawback that it has poor long-term durability because it has a low degree of crystallinity and thus a low antioxidant property.

The present invention solves the above-mentioned problems, in which a water blocking filler is filled in advance before the steel sheet pile is struck, and the water blocking filler and the fitting joint are By ensuring that the male joints of post-strike steel sheet piles can be fitted and installed while ensuring a large degree of adhesion and adhesion with the joint steel, which is important for water-stopping performance, stricter water-stopping performance can be achieved. It is an object of the present invention to provide a method of forming a waterproof joint having.

[0014]

In order to achieve the above-mentioned object, the present invention is constructed as follows.

A first aspect of the present invention is a method of stopping water in a joint portion, in which a pair of fitting joints are fitted to each other via a water blocking filler and a steel sheet pile such as a steel sheet pile and a steel pipe sheet pile is driven. There
A pre-strike steel sheet pile, which has been filled with a viscoelastic material containing asphalt as a main component as a waterproofing filler in the joint space, is driven into a predetermined location of the ground, and subsequently the joint portion is filled with the viscoelastic material. When inserting the joint of the post-strike steel sheet pile into the space, the post-strike steel sheet pile is inserted and driven while giving a vibration of a predetermined frequency or higher or giving a shock.

In a second aspect based on the first aspect, the pair of fitting joints comprises a male joint and a female joint, the male joint has a T shape, and the female joint has a circular or square pocket. It is a joint having a configuration and a slit for fitting a T-shaped joint, wherein the pocket portion of the female joint is previously filled with a viscoelastic material mainly composed of water-stopping asphalt. Let's say it is a feature.

According to a third aspect of the present invention, in the first aspect of the present invention, the pair of fitting joints are joints for fitting the jointed steel pipes each having a slit in the steel pipes, and only one of the jointed steel pipes has a pocket portion. It is characterized in that a viscoelastic material containing asphalt for water blocking as a main component is filled in advance.

A fourth invention is characterized in that, in any one of the first to third inventions, the water-stopping filling material to be filled in the fitting joint in advance is a rubber asphalt compound.

In a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, in a fitting joint of a steel sheet pile such as a steel sheet pile or a steel pipe sheet pile that is cast on the ground, a portion projecting from the ground is provided.
It is characterized in that a means for preventing the water blocking filler from leaking through the slit provided in the fitting joint is provided.

A sixth aspect of the invention is the fitting joint according to the second aspect of the invention.
A leak preventer for a water blocking filler according to the invention is provided, wherein the leak preventer is fixed to both sides or one side of a base of a T-shaped joint, and a tip end side surface is elastically attached to an outer peripheral surface of the joint steel pipe. It is constituted by an elastic leak-preventing plate that is in close contact with each other, and is provided so as to close the slit of the joint steel pipe.

A seventh aspect of the invention is the fifth aspect of the fitting joint of the second aspect of the invention.
A means for preventing leakage of a water blocking filler according to the invention is provided, wherein the means for preventing leakage is mortar restraint so as to be positioned in parallel to the base of the T-shaped joint and on both sides or one side of the large diameter portion of the joint steel pipe. Steel plate for steel pipe sheet pile main body steel pipe, the mortar restraint steel plate and the base of the T-shaped joint, and the gap formed between the outer peripheral surface of the joint steel pipe 8 is configured by filling mortar, the slit of the joint steel pipe It is characterized in that it is provided so as to close.

An eighth invention is the fitting joint according to the third invention, which is the fifth invention.
A leak preventer for a water blocking filler of the invention is provided, wherein the leak preventer comprises a joint steel pipe on the side opposite to the side filled with the viscoelastic filler and is filled with mortar,
Alternatively, the half-divided steel pipe provided in this joint steel pipe filled with mortar is also configured by filling the mortar, and is provided so as to close the slit of the joint steel pipe.

A ninth aspect of the present invention is the water stopping method according to any one of the first to eighth aspects, wherein a slit of a portion of a fitting joint such as a steel sheet pile and a steel pipe sheet pile that projects into the ground projects from the ground. In addition to providing a means for preventing the viscoelastic filler from leaking, a means for preventing the joint portion from separating due to a tensile force acting on the joint portion is provided.

A tenth aspect of the present invention is the ninth aspect of the present invention, which is applied to the water stopping method for a steel sheet pile joint portion according to any one of the second to fifth or eighth aspects, wherein the joint separation preventing means is T The steel plate for mortar restraint is provided on the steel pipe sheet pile main body steel pipe so as to be positioned parallel to the base of the type joint and on both sides or one side of the large diameter portion of the joint steel pipe, and the engagement protrusion provided on the steel plate for mortar restraint, It is characterized by comprising a tension transmission key provided on the joint steel pipe so as to be engaged with the engaging portion.

An eleventh aspect of the present invention is the ninth aspect of the present invention, which is applied to the water stopping method for a steel sheet pile joint portion according to any one of the second to fifth or eighth aspects, wherein the joint separation preventing means is T The steel sheet for mortar restraint is provided on the steel pipe sheet pile body steel pipe so as to be located parallel to the base of the die joint and on both sides or one side of the large diameter portion of the joint steel pipe.The steel pipe for mortar restraint has the joint steel pipe in the joint separation direction. It is characterized in that it is composed of an engagement projection provided so as to engage the large diameter portion of the joint steel pipe when moving.

A twelfth invention is characterized in that, in any one of the first to eleventh inventions, a blade portion is formed at a lower end portion of a T-joint or a joint steel pipe which is a post-strike side.

A thirteenth invention is the twelfth invention, wherein
The blade-shaped portion formed on the flange portion of the T-shaped joint and the blade-shaped portion formed at the lower end of the long claw-side fitting section of the joint steel pipe are separated from the steel pipe sheet pile body steel pipe of the leading end as the vertical surface and the upper portion increase. It is characterized in that it is formed by an inclined surface inclined in the direction.

[0028]

According to the present invention, the joint space is not filled with the water blocking material after the steel sheet piles such as the steel sheet pile and the steel pipe sheet pile are driven, but asphalt is used as the main component in the joint space before the steel sheet piles are driven. Since the viscoelastic material to be filled is filled in, earth and sand do not enter the joint space after driving.

On the other hand, however, since the viscoelastic material containing asphalt as the main component has a large adhesive force and adhesive force with the steel material, it is attempted to push the male joint to be driven in later into the female joint filled with the filler. In this case, the male joint drags the surrounding filling material, resulting in a large resistance. Therefore, a very large force is required to push it in, which makes it impossible to construct a long product.

According to experiments conducted by the present inventors in this regard,
The viscoelastic material mainly composed of asphalt exerts a large adhesive force and adhesive force with the steel material against static force, but when the steel material is vibrated, the adhesive force and adhesive force are rapidly increased. It was also confirmed that when the vibration frequency exceeds about 10 Hz, the adhesive force / adhesive force becomes considerably small, and it becomes so small as to cause almost no problem at the time of driving.

Further, according to the experiments conducted by the present inventors, even when a certain amount of impact is applied to the steel material instead of vibration, the adhesive force and the adhesive force of the steel material are rapidly reduced. That is, when an impact is applied such that the displacement speed of the steel material exceeds approximately 50 kine, the adhesive force between the viscoelastic material containing asphalt as the main component and the steel material is considerably reduced, and there is almost no problem when driving the male joint to be driven later. It was confirmed that it would be small enough not to become.

The first idea created based on the above experimental results
According to the invention, at the time of driving the male joint, the viscoelastic material containing asphalt as a main component is filled while vibrating the steel sheet pile with a vibro hammer or the like or by vibrating it with a disel hammer or a hydraulic hammer. By performing the fitting while fitting the male fitting into the female fitting, it is possible to construct the steel sheet pile while easily inserting the male fitting so as to cut the filler.

Further, after the fitting joint is once formed, the viscoelastic material containing asphalt as a main component has a large adhesive force and adhesive force with the steel material, so that the joint may be bent and deformed or pulled. Even if the joint is deformed in the direction in which it separates due to the force, there is no gap or gap between the joint and the filler, and excellent water-stopping performance can be exhibited. Also,
Since the asphalt material is a material having excellent long-term durability, it can maintain excellent water-stopping performance for a long period of time.

Further, in order for the water blocking filler to absorb various deformations acting on the joint while ensuring adhesion with the steel material,
It is desirable that the contact area between the filler and the steel material is large and that the filler has a capacity and a cross-sectional area such that deformation can be absorbed. As in the second and third inventions, the joint is filled with water-proof filler. It has a pocket for filling the material, which is filled with the filling material, and the T-shaped or arc-shaped joint steel material is inserted into the pocket portion to increase the contact area between the joint steel material and the waterproof filler. A joint structure that can be secured is desirable.

The rubber asphalt compound of the fourth invention is straight asphalt to which synthetic rubber of SBS is added. When the rubber asphalt compound is pressure-bonded to a steel surface or a concrete surface, an air layer is formed at the interface. Since the adhesive area is extremely small in the initial stage, there is little resistance when fitting and placing the joint, while on the other hand, the air layer becomes finer with the passage of time and completely disappears after several weeks and the entire area disappears. Has been found to adhere, and has the effect of adhering to the steel surface and exhibiting excellent water impermeability over the long term. Further, by mixing rubber into the asphalt, the softening point is increased and the stiffness coefficient is increased, so that there is an advantage that the flow of asphalt during transportation and the long-term leakage of the filler can be suppressed.

On the other hand, the viscoelastic material containing asphalt as a main component exhibits fluidity as a long-term behavior for several years to several tens of years, and behaves as a viscous fluid. Therefore, the filling material gradually leaks from the slit portion provided in the female joint. If the joint is in the soil, the restraint of the soil around the joint will prevent leakage of the filler,
If the joint is protruding from the sea bottom or if the surrounding ground is gravel with large voids, the filler cannot escape because the filler cannot stay inside the joint due to leakage of the filler. However, it becomes impossible to maintain the waterproof property.

Further, when the steel sheet pile wall is applied to a seawall, one side of the wall is in contact with soil, but the other side is in contact with river and sea water. There is a leak problem. Therefore, if the slit portion of the joint is in a state where restraint by soil cannot be expected, by taking measures to prevent leakage of the filler as in the fifth to ninth inventions, the filler can be stopped for a long time. Water performance can be demonstrated.

On the other hand, if the water-proof filler is soft like an asphalt mixture, when the compressive force or tension acts on the joint due to the deformation of the surrounding ground, there is no resistance mechanism, so the steel sheet pile installation situation. Depending on the situation, a large displacement may occur in the joint. In particular, when the joint is largely displaced in the separating direction or when the load is repeatedly applied in the compression and tension directions, the adhesive surface between the steel surface and the filler may be peeled off, and the waterproof property may be impaired. . When the joint is largely displaced in the separating direction, a new gap will be generated in the leakage prevention mechanism of the filler,
The leakage prevention mechanism will be impaired. Even in such a case, a large displacement of the joint can be suppressed by applying a method such as the tenth to twelfth inventions in which a large displacement in the separating direction does not occur in the joint, so that the waterproofness is secured. Is possible.

According to the twelfth invention, the first to eleventh aspects are provided.
In addition to the efficient driving of steel pipe sheet piles utilizing vibration and impact in the invention, a blade portion provided at the lower end of the T-shaped joint or the joint steel pipe that is the post-strike side is filled in the pre-strike joint steel pipe. The post-strike steel pipe sheet pile can be more smoothly inserted into the pre-strike steel pipe sheet pile while reducing the penetration resistance of the viscoelastic filler.

Further, as in the thirteenth invention, the inclined surface of the blade portion provided on the web of the T-type joint and the inclined surface provided in the long-claw side fitting section of the joint steel pipe are advanced as the steel pipe sheet pile is struck. By inclining in the direction away from the main body steel pipe, when the post-strike steel pipe is driven, it is easy to deviate in the direction away from the pre-strike steel pipe sheet pile, but the inclined surface guides both steel pipe sheet piles toward each other. As a result, it is possible to cancel the movement in the separation direction from the side of the pre-cast steel pipe sheet pile and smoothly place the steel pipe.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 9 show Embodiments 1 to 9, and in each figure, in a water blocking wall such as a waste disposal site constructed by steel pipe sheet pile walls, a viscoelastic filler for stopping water is made of steel. Fig. 2 is an enlarged cross-sectional view of the joint portion of the steel pipe sheet pile, which is made of a viscoelastic material having excellent adhesion and is provided with leakage prevention means for preventing this viscoelastic filler from leaking from the slit of the joint portion. ing.

The components common to the fitting type joints shown in FIGS. 1, 4 to 6, 8 and 9 will be described. One of the steel pipe sheet pile main body steel pipes 5 is provided with a slit 7 through a weld portion 6. A joint steel pipe (female joint) 8 is provided, and a T-shaped joint (male joint) 10 is attached to the other steel pipe sheet pile body steel pipe 5 via a welded portion 6.
And the joint steel pipe 8 is filled with a rubber asphalt compound or a viscoelastic filler 11 containing asphalt as a main component.

Further, in FIG. 3, two joint L-shaped steel (female joints) 8c are arranged so that the hook-shaped portions face each other so that the slits 7 are formed in the steel pipe 5 of one steel pipe sheet pile body through the welded portions 6. And the other steel pipe sheet pile main body steel pipe 5 is provided with a T-shaped joint (male joint) 10 via a welded portion 6, and a joint L
A rubber asphalt compound or a viscoelastic filler 11 containing asphalt as a main component is filled inside the shaped steel (female joint) 8c.

2 and 7 show a joint of a joint pipe system different from the above. In this example, both steel pipe sheet pile main body steel pipes 5 are provided with joint steel pipes 8 and 8a having slits 7 through welded portions 6. A rubber asphalt compound or a viscoelastic filler 11 containing asphalt as a main component is pre-filled in one joint steel pipe 8 before the steel pipe sheet pile is placed. The mortar 23 is filled in the other joint steel pipe 8a after the steel pipe sheet pile is placed.

When the steel pipe sheet pile main body steel pipes 5 are connected to each other by the joint steel pipe 8 which is filled with the viscoelastic filler 11 in advance and the T-shaped joint 10 to form a wall body with a large number of steel pipe sheet piles, Side and B side are partitioned in a watertight manner. A side and B
There are cases where each side is underwater, one side is soil and the other side is underwater, and both sides are soil.

In each of the joints described above, if the viscoelastic filler 11 is not filled, a gap exists between the joint steel pipe 8 and the T-shaped joint 10, and the slits 7 and T of the joint steel pipe 8 are formed. Since the gap 13 exists between the webs 10a of the joint 10, the A side and the B side communicate with each other, and a problem of leakage of sewage from the joint occurs. For this reason, it has been conventionally practiced to fill the voids in the joint portion with the water blocking filler after or before driving the steel sheet pile.

In the above case, if the water-stopping filler is filled in the voids of the joint steel pipe 8 before the steel sheet pile is driven, the voids of the joint steel pipe 8 will be covered with earth and sand when the steel sheet pile is driven. There is an advantage that it does not enter and does not impair the quality of the water blocking filler, and the rubber asphalt compound according to the present invention and the viscoelastic material 11 mainly containing asphalt are also pre-filled in the voids of the joint steel pipe 8. By setting it, it is possible to eliminate the possibility that earth and sand enter the joint steel pipe 8 when the steel sheet pile is placed.

However, in this case, since the viscoelastic filler 11 has a large adhesive force and adhesive force with the joint steel material, the T-shaped joint 10 (male joint) to be driven later is pushed into the joint steel pipe 8 (female joint). In the other case, the male joint drags the viscoelastic filler 11 around the male joint, resulting in a large resistance. For this reason, a very large force is required to push in the T-shaped joint 10, so that a long joint structure cannot be constructed.

In the embodiment of the present invention, the viscoelastic filler 11 composed mainly of asphalt, which exhibits fluidity as a long-term behavior for several years to several decades but has little fluidity in the short term, is made of steel. The gap of the joint steel pipe 8 is pre-filled before the driving of the sheet pile, and the difficulty of driving the T-shaped joint 10 of the post-cast steel pipe sheet pile at this time is overcome by a new method. That is, this embodiment is a T-shaped joint 10 of a post-cast steel sheet pile.
Is driven into the viscoelastic filler material 11 containing asphalt as a main component, which is pre-filled in the voids of the joint steel pipe 8 of the pre-punched steel sheet pile, it is inserted while giving a vibration of a predetermined frequency or more, specifically a vibration of 10 Hz or more. It's something to type in.

The action and effect of inserting the T-shaped joint 10 of the post-punched steel sheet pile into the viscoelastic filler 11 while applying vibration of a predetermined frequency and driving it have been clarified by the experimental results of the present inventor. According to this experiment, the viscoelastic material 11 containing asphalt as a main component exerts a large adhesive force and an adhesive force between the steel material and the steel material against static force. It was confirmed that the adhesive force and the adhesive force sharply decreased. Furthermore, when the vibration frequency when placing a sheet pile exceeds about 10 Hz, its adhesive force and adhesive force become considerably small,
It has been confirmed that it becomes small enough to cause almost no problem at the time of driving.

According to the results of further experiments conducted by the present inventors, the asphalt can also be inserted by impacting with a predetermined value or more, specifically about 50 kine or more, in place of the above vibration, and driving the asphalt. It was confirmed that the viscoelastic material as the main component and the steel material can be effectively inserted and driven while cutting the adhesive force.

An example will be described. The present inventor conducted a joint performance confirmation test of workability and water impermeability of a joint in which a steel pipe of a PT joint was filled with an asphalt mixture in a factory. In the construction test, two P-side joints with a length of 7 m were installed with their slits facing each other, and H-shaped steel to be the T-side joint was placed while vibrating with a vibro hammer (22 kW). , The fitting fits smoothly.

In the water-impervious test, the joint was left for 90 days, and then 0.1 M to 0.1-0.5 MPa was measured with a pressure tester.
The water pressure was changed at a pitch of Pa (corresponding to a water level difference of 10 m) and loaded at each pressure for 1 hour, but no water leakage from the joint part was observed.

Therefore, in the present invention, when the T-shaped joint 10 is driven, the viscoelastic material 1 containing asphalt as a main component is applied to the steel sheet pile while vibrating or impacting with a vibro hammer, a disel hammer, a hydraulic hammer or the like.
By performing the T-type joint 10 while fitting the T-type joint 10 into the joint steel pipe 8 filled with 1, the steel sheet pile is installed while the T-type joint 10 is easily inserted so as to cut the viscoelastic filler 11. I realized that I can do it.

Moreover, according to the present invention, since the joint space of the steel pipe sheet pile is filled with the viscoelastic material 11 containing asphalt as a main component before the sheet pile is driven, the intrusion of earth and sand into the joint space does not occur after the sheet pile is driven. Absent.

After the fitting joint is once formed, the viscoelastic material 11 containing asphalt as a main component is
Due to the large adhesive force and adhesive force with the steel material, even if bending deformation acts on the joint part or if the tensile force acts and deforms the joint away from it, a gap or gap will occur between the joint and the filler. In fact, it can exhibit excellent water-stopping performance.
Moreover, since the asphalt material is a material having excellent long-term durability, it can maintain excellent water-stopping performance for a long period of time.

Further, the rubber asphalt compound is
Synthetic rubber of SBS is added to straight asphalt, but if the water blocking filler is made of rubber asphalt compound, an air layer will be formed at the interface when it is pressure-bonded to this and the steel surface. Since the area is extremely small in the initial stage, there is little resistance when fitting and placing the joint, while on the other hand, the air layer becomes finer over time and disappears completely after a few weeks and the entire area adheres. It has been found that, in the long term, it will adhere to the steel surface and exhibit excellent water impermeability.

Further, by mixing rubber into the asphalt, the softening point is increased and the stiffness coefficient is increased, so that there is an advantage that the flow of the asphalt during transportation and the long-term leakage of the filler can be suppressed.

On the other hand, each of the above-mentioned viscoelastic fillers 11 may leak from the slit 7 of the joint portion in the long term. If the joint is in the soil, the leakage of the filler does not occur due to the restraint of the soil around the joint, but when the steel sheet pile wall is applied to a seawall, one side of the wall is in contact with the soil. However, the other side is in contact with river and sea water, and when the slit part of the joint cannot be expected to be restrained by soil in this way, or when the joint protrudes from the sea floor, In the case where the surrounding ground is gravel or the like with large voids, the filler cannot stay in the joint, and the filler gradually deviates, making it impossible to maintain the water stopping property.

From the above, in each embodiment, as shown in each drawing, the viscoelastic filler 11 is prevented from leaking.

In the fourth embodiment shown in FIG. 4, the base end portion of the elastic leakage prevention plate 16 extending in the vertical direction is provided on both sides of the web 10a of the T-shaped joint 10 provided on the steel pipe sheet pile main steel pipe 5 on one side. And the web 1 of the T-joint 10
0a, the bolt insertion hole 17 formed in the root portion of the elastic leak prevention plate 16, and the bolt insertion hole 18 formed in the elastic leakage prevention plate 16 are inserted through the fixing bolts 19. Are fastened integrally to the T-type joint 10. The elastic leak-prevention plate 16 is constructed by sticking a pressing steel plate 15 to the outside of the leak-prevention rubber plate 14.

Therefore, as shown in FIG. 4, the leakage prevention rubber plate 14 of the elastic leakage prevention plate 16 comes into close contact with the outer peripheral surfaces of the joint steel pipes 8 on both sides of the slit 7 by the strong spring force of the pressing steel plate 15. When the viscoelastic filler 11 leaks from the slit 7 due to excessive passage for a long time, it is confined in a small space surrounded by the elastic leak prevention plates 16 on both sides and the outer peripheral surface of the joint steel pipe 8 on both sides of the slit 7, Do not leak to.
In FIG. 4, elastic leak prevention plates 16 are provided on both sides of the T-shaped joint 10. However, when either one of the A side and the B side is in contact with soil, the elastic leak prevention of the side in contact with the soil is prevented. Board 16
May be omitted.

FIG. 5 shows a fifth embodiment. This Embodiment 5
In the steel pipe sheet pile body steel pipe 5
On both sides of the web 10a of the mold joint 10 and in parallel with the web 10a, mortar restraining steel plates 21 extending in the up-down direction along the surface of the steel pipe sheet pile main body steel pipe 5 are provided. It is arranged so as to be spaced outward from the maximum diameter portion.

Further, in cavities formed between the mortar restraining steel plates 21 on both sides and both sides of the web 10a of the T-shaped joint 10 and the outer peripheral surfaces of the joint steel pipes 8 located on both sides of the slit 7 therebetween, The mortar 23 is filled so as to be housed in the mortar jacket (bag) 30. The mortar 23 is filled so that the mortar 23 is filled with the mortar 23 after the T-type joint 10 is sunk and the mortar jacket 30 is inserted into the gap with a pushing rod or the like.

Therefore, in the fifth embodiment of FIG. 5 and the sixth embodiment of FIG. 6, the mortar 23 is in close contact with the outer peripheral surfaces of the joint steel pipes 8 on both sides of the slit 7, with the slit 7 interposed therebetween.
The viscoelastic filling material 11 leaking from the slit 7 due to the excessive passage of time for a long time is confined in a small void portion to prevent leakage to the outside.
Also in FIG. 5, the mortar 23 is provided on both sides of the T-type joint 10, but when either one of the A side and the B side is in contact with the soil, the mortar housing means on the side in contact with the soil may be omitted. Good.

Further, as in the sixth embodiment shown in FIG. 6, the mortar leakage prevention plate 2 is attached to the tip of the mortar restraining steel plate 21.
By providing No. 4, it is possible to adopt a method of directly filling the voids with mortar without using the mortar jacket.
In the above case, the side surface of the base end portion of the mortar leakage prevention plate 24 made of a rubber plate or the like is applied to the inside of the tip end portions of both mortar restraining steel plates 21, and the fixing bolt 19 inserted through the abutting portion.
With the nut 20, the base end of the mortar leakage prevention plate 24 is fixed to the mortar restraining steel plate 21 via the presser band steel plate 22. The tip side of the mortar leakage prevention plate 24 is folded back inward, and due to its elasticity, it is in close contact between the outer peripheral surfaces of the joint steel pipes 8 located on both sides of the slit 7 with the elasticity therebetween.

FIG. 7 shows the seventh embodiment. This Embodiment 7
Indicates a joint of a joint pipe system, and in this example, joint steel pipes 8 and 8a having slits 7 are provided in both steel pipe sheet pile main body steel pipes 5 via welded portions 6, and one of the joint steel pipes 8 is made of rubber. An asphalt compound or a viscoelastic filler 11 containing asphalt as a main component is pre-filled before driving a steel pipe sheet pile. The mortar 23 accommodated in the mortar jacket 22 is filled in the other joint steel pipe 8a after the steel pipe sheet pile is placed. Further, a half-divided steel pipe 27 is fixed to the other joint steel pipe 8a, and the half-divided steel pipe 27 is also housed in the mortar jacket 22 to accommodate the mortar 23.
Is filled after the steel pipe sheet pile is placed. Also in this case, in addition to the method of using the mortar jacket, there is also a method of fixing a mortar leakage prevention plate such as a rubber plate to the slit portion and directly filling the void portion with the mortar.

After the mortar 23 is filled with the mortar 23 after the joint steel pipe 8a is sunk, the mortar jacket 30 is inserted into the joint steel pipe 8a and the half-split steel pipe 27 with a pushing rod or the like. To be filled.

In the seventh embodiment, the viscoelastic body filler 11
Since the slit 7 of the joint steel pipe 8 filled with is closed by the mortar 23 filled in the joint steel pipe 8a and the mortar 23 filled in the half-divided steel pipe 27, viscoelastic filling leaking from the slit 7 due to excessive passage for a long time. Prevent the material 11 from leaking. In the sixth embodiment, the half steel pipe 27 side (B in the figure).
When the side) is in contact with the soil, the mortar containing means by the half steel pipe 27 in contact with the soil may be omitted.

FIG. 8 shows the eighth embodiment. This Embodiment 8
In the steel pipe sheet pile body steel pipe 5
On both sides of the web 10a of the mold joint 10 and in parallel with the web 10a, mortar restraining steel plates 21 extending in the up-down direction along the surface of the steel pipe sheet pile main body steel pipe 5 are provided. The mortar restraining steel plate 21 is provided with an engaging projection 28 projecting from the joint steel pipe 8 at the tip of the mortar restraining steel plate 21 while being arranged so as to be spaced apart from the maximum diameter portion. Further, on the outer peripheral surface of the joint steel pipe 8, the engaging projection 2
A pulling transmission key 29 is provided on the inner side of 8.

Further, it is formed between both sides of the mortar restraining steel plate 21 and the web 10a of the T-shaped joint 10, the outer peripheral surfaces of the joint steel pipe 8 located on both sides of the slit 7 with the slit 7 in between, and the tension transmission key 29. The space is filled with the mortar 23 which is housed in the mortar jacket (bag) 30. The mortar 23 is filled so that the mortar 23 fills the mortar jacket 22 after the mortar jacket 30 is inserted into the gap by a push rod or the like after the T-type joint 10 is deposited.

In the eighth embodiment, the mortar 23 is in close contact with the outer peripheral surfaces of the joint steel pipes 8 on both sides of the slit 7 with the slit 7 sandwiched therebetween, and the viscoelastic filler 11 leaking from the slit 7 due to the excessive passage of the slit 7 for a small void portion. To prevent leakage to the outside. Further, in the seventh embodiment, when a tensile force acts on the joint steel pipe 8 and the T-shaped joint 10, the tension transmission key 29 provided on the joint steel pipe 8 engages with the engagement protrusion 28 at the tip of the mortar restraining steel plate 21. By doing so, the separation can be reliably prevented. Also in the seventh embodiment, the jacketed mortar 23 is provided on both sides of the T-type joint 10, but when either one of the A side and the B side is in contact with the soil, the mortar housing means on the side in contact with the soil is provided. It may be omitted.

FIG. 9 shows a ninth embodiment. This Embodiment 9
In the steel pipe sheet pile body steel pipe 5
On both sides of the web 10a of the mold joint 10, parallel to the webs 10a, mortar restraining steel plates 21 extending vertically are provided along the surface of the steel pipe sheet pile main steel pipe 5. At the tip of the mortar restraining steel plate 21, the engagement protrusion 31 has such a dimensional relationship that the outer peripheral surface of the large diameter portion of the joint steel pipe 8 engages when the joint steel pipe 8 moves in a direction away from the T-type joint 10. Is provided.

Further, a base end side surface of a mortar leakage prevention plate 24 made of a rubber plate or the like is applied to the inside of the engaging protrusion 31, and a mortar leakage prevention plate is fixed by a fixing bolt 32 inserted through the abutting portion. The mortar restraining steel plate 2 has a base end 24.
It is fixed to 1. The tip side of the mortar leakage prevention plate 24 is folded back inward, and due to its elasticity, the joint steel pipe 8
Close to the outer peripheral surface of. When the mortar is filled with the mortar jacket, the mortar leakage plate 24 can be omitted.

Further, the mortar is formed in the closed space formed between both sides of the mortar restraining steel plate 21 and the web 10a of the T-type joint 10 and the outer peripheral surfaces of the joint steel pipes 8 located on both sides of the slit 7 therebetween. 23 is filled.

Therefore, also in the ninth embodiment, the mortar 23 is in close contact with the outer peripheral surfaces of the joint steel pipes 8 on both sides of the slit 7 over a wide range, and viscoelasticity leaks from the slit 7 due to long-time excess. The leakage of the filler 11 is prevented. Although the mortar 23 is provided on both sides of the T-type joint 10 also in the sixth embodiment, if either one of the A side and the B side is in contact with soil, the mortar housing means on one side may be omitted.

10 and 11 show Embodiments 10 and 11, and each embodiment has the features of Embodiments 1 to 9, namely,
In addition to the fact that the joint member of the post-strike steel pipe sheet pile can be placed while smoothly cutting off the adhesion with the viscoelastic filler 11 by vibration or impact, the post-strike joint steel pipe (female joint) 8 is post-strike
When the mold joint (male joint) 10 or the joint steel pipe 8a is driven, the viscoelastic filler 11 filled in the pre-strike joint steel pipe (female joint) 8 can be smoothly driven while cutting it more smoothly. An example in which a blade-shaped portion that reduces the penetration resistance is provided is shown below.

To further explain FIG. 10, the joint steel pipe 8 (which is on the pre-strike side) and the T pipe are placed at symmetrical positions on the outer periphery of the steel pipe sheet pile main pipe 5.
A mold joint 10 (to be the post-strike side) is provided. At the lower end of the T-shaped joint 10, a blade portion 32 formed of a tapered taper portion is provided at the lower end of the web portion 10a, and a blade portion 33 also formed of a tapered taper portion is provided at the lower end of the flange portion 10b. Due to the presence of the blade-shaped portions 32 and 33, when the T-type joint (male joint) 10 is driven by post driving,
The viscoelastic filler material 11 (referring to another drawing, not shown in FIG. 10) filled in the pre-strike joint steel pipe (female joint) 8 is smoothly driven while the blade portions 32 and 33 reduce the penetration resistance. Can be set.

Further, the blade portion 33 has a vertical surface 33b.
And the inclined surface 33a that is inclined in a direction away from the steel pipe sheet pile main body steel pipe 5 that is punched as it goes upward. As a result, the post-strike steel pipe sheet pile is apt to shift in the direction of separating from the pre-strike steel pipe sheet pile at the time of its driving, but the inclined surface 33a of the blade portion 33 guides both steel pipe sheet piles in the approaching direction. It is possible to cancel the movement of the post-cast steel pipe sheet pile in the direction of separation from the pre-cast steel pipe sheet pile side and smoothly place the post-cast steel pipe sheet pile.

Next, in FIG. 11, joint steel pipes 8 and 8a are provided at positions symmetrical to the outer periphery of the steel pipe sheet pile main pipe 5. In the joint steel pipe 8a on the post-strike side, the longer one from the welded portion 6 to the side end of the slit 7 is defined as the joint portion long claw portion 34a,
The shorter portion from the welded portion 6 to the side end of the slit 7 is referred to as the joint short claw portion 34b. In addition, in the joint steel pipes 8 and 8a fitted to each other through the slit 7, the range from the tip of the joint long pawl portion 34a to the slit 7 of the mating joint steel pipe 8 is defined as the long pawl side fitting section 35. Joint steel pipe 8a that will be driven later
A blade portion 36 is provided at the lower end of the long claw side fitting section 35.

The blade portion 36 is formed by a vertical surface 36b and an inclined surface 36a which is inclined in a direction away from the steel pipe sheet pile main body steel pipe 5 which is punched upward as it goes upward.
Thereby, when the post-strike steel pipe sheet pile is driven, the inclined surface 36a of the blade portion 36 guides both steel pipe sheet piles in the direction of approaching each other, so that the post-strike steel pipe sheet pile is separated from the pre-cast steel pipe sheet pile side. It is possible to eliminate the tendency of slipping and to smoothly place the blade-like portion 36 while reducing the penetration resistance of the viscoelastic filler 11 (other figures are not shown in FIG. 11).

It should be noted that it is within the scope of the present invention to appropriately change the design of the configuration shown in each of the embodiments.

[0084]

According to the present invention, one joint of a steel sheet pile filled with a viscoelastic material containing asphalt as a main component is applied to one joint of the other punched steel sheet pile while vibrating at a frequency higher than a predetermined frequency. By fitting and fitting, it is possible to construct the steel sheet pile while inserting the latter joint so as to cut the viscoelastic filler, and furthermore, since the viscoelastic filler is pre-filled in the joint. , Sediment does not penetrate into the joint when the steel sheet pile is sunk.

Further, after the fitting joint is once formed, the viscoelastic material containing asphalt as a main component has a large adhesive force and adhesive force with the steel material, so that the joint may be bent and deformed or pulled. Even when the joint is deformed in the direction of leaving due to the force, the adhesive force and the adhesive force are large, so there is no gap or gap between the joint and the filler, and excellent water stopping performance can be exhibited. . Moreover, since the asphalt material is a material having excellent long-term durability, it is possible to maintain excellent water-stopping performance for a long period of time.

As described above, according to the present invention, in the fitting joint portion of the steel sheet pile, the post-strength steel can be secured while ensuring the large adhesion and tackiness of the joint steel material and the viscoelastic filler, which are important for the waterproof performance. By allowing the fitting of the joint of the sheet pile to be possible, it was possible to form a waterproof joint having more strict waterproof performance.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a first embodiment.

FIG. 2 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a second embodiment.

FIG. 3 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a third embodiment.

FIG. 4 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a fourth embodiment.

FIG. 5 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a fifth embodiment.

FIG. 6 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a sixth embodiment.

FIG. 7 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a seventh embodiment.

FIG. 8 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to an eighth embodiment.

FIG. 9 is an enlarged cross-sectional view of a joint portion of a steel pipe sheet pile according to a ninth embodiment.

10A is a perspective view of a steel pipe sheet pile having a P-T type joint portion according to Embodiment 10, and FIG. 10B is an enlarged bottom view of the joint portion.

FIG. 11A is a perspective view of a steel pipe sheet pile having a P-P type joint portion according to the eleventh embodiment, and FIG. 11B is an enlarged bottom view of the joint portion.

FIG. 12 shows a conventional example, (a) a plan view of an impermeable wall of a sea surface landfill industrial waste disposal site composed of steel pipe sheet pile walls, (b),
(C) is AA, BB sectional drawing of (a), respectively.

[Explanation of symbols]

1 steel sheet pile 1a Main body steel pipe 2 joint 2a male joint 2b female fitting 3 water stop materials 4 Sea surface landfill 5 Steel Pipe Sheet Pile Main Steel Pipe 6 welds 7 slits 8 joint steel pipe (female joint) 8a Joint steel pipe (female joint) 8b Joint steel pipe (female joint) 8c Joint L-shaped steel (female joint) 9 Hollow part 10 T-type fitting (male fitting) 10a Web Department 10b Flange part 11 Viscoelastic filler 14 Leakage prevention rubber plate 15 Presser plate 16 Elastic leak prevention plate 17 Bolt insertion hole 18 bolt insertion hole 19 Fixing bolt 20 nuts 21 Steel plate for mortar restraint 22 Presser band steel plate 23 Mortar 25 fixing bolt 26 nuts 27 half steel pipe 28 Engagement protrusion 29 Tension transmission key 30 mortar jacket 31 Engagement protrusion 32 blade 33 Edge 33a vertical part 33b inclined surface 34a Joint long claw part 34b Joint short claw part 35 Long Claw Side Fitting Section 36 Flute 36a vertical part 36b slope

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Onuki             2-6-3 Otemachi, Chiyoda-ku, Tokyo New Japan             Steelmaking Co., Ltd. (72) Inventor Tetsuo Kimura             2-6-3 Otemachi, Chiyoda-ku, Tokyo New Japan             Steelmaking Co., Ltd. (72) Inventor Fumihiro Hirano             2-6-3 Otemachi, Chiyoda-ku, Tokyo New Japan             Steelmaking Co., Ltd. F-term (reference) 2D018 BA15                 2D049 EA03 FB03 FB14 FC02 FC03                       FD01

Claims (13)

[Claims] 1. A method of stopping water in a joint portion, in which a pair of fitting joints are fitted to each other via a water blocking filler and a steel sheet pile such as a steel sheet pile and a steel pipe sheet pile is driven. A joint steel part space in which a pre-strike steel sheet pile, which has been filled with a viscoelastic material containing asphalt as a main component as a water blocking filler in advance, is driven into a predetermined portion of the ground, and subsequently the viscoelastic material is filled. A method for stopping water at a steel sheet pile joint part, characterized in that, when inserting a joint of a post-punched steel sheet pile, the post-punched steel sheet pile is inserted and driven while vibrating at a predetermined frequency or higher, or while giving a shock. 2. The pair of fitting joints comprises a male joint and a female joint, the male joint is T-shaped, and the female joint is shaped to form a pocket such as a circle or a square, and the joint is T-shaped. The steel according to claim 1, wherein the joint has a slit for fitting thereinto, and the pocket portion of the female joint is pre-filled with a viscoelastic material containing asphalt for waterproofing as a main component. How to stop water from the sheet pile joints. 3. The pair of fitting joints are joints for fitting together the jointed steel pipes having slits in the steel pipes, and one of the jointed steel pipes is preliminarily made of asphalt for waterproofing as a main component. The method for stopping water in a steel sheet pile joint according to claim 1, wherein the viscoelastic material is filled. 4. The water blocking material for a steel sheet pile joint according to claim 1, wherein the water blocking filler material to be pre-filled in the fitting joint is made of rubber asphalt compound. Method. 5. In a fitting joint for steel sheet piles such as steel sheet piles and steel pipe sheet piles cast on the ground, a water blocking filler leaks from a slit provided in the fitting joint at a portion protruding from the ground. The method for stopping water in a steel sheet pile joint according to any one of claims 1 to 4, wherein a means for preventing the water is applied. 6. The fitting joint according to claim 2 is provided with means for preventing leakage of the water blocking filler according to claim 5,
The leakage prevention means is fixed to both sides or one side of the base portion of the T-type joint, and is configured by an elastic leakage prevention plate whose tip end side face elastically comes into close contact with the outer peripheral surface of the joint steel pipe to close the slit of the joint steel pipe. A method of stopping water in a steel sheet pile joint portion, which is characterized in that 7. The fitting joint according to claim 2 is provided with means for preventing leakage of the water blocking filler according to claim 5,
The leakage prevention means is such that the mortar restraining steel plate is provided on the steel pipe sheet pile main body steel pipe so as to be positioned parallel to the base of the T-type joint and on both sides or one side of the large diameter portion of the joint steel pipe. The base portion of the joint and the outer peripheral surface of the joint steel pipe 8 are filled with mortar in a space formed between them,
A method for stopping water in a steel sheet pile joint, which is provided so as to close a slit of the joint steel pipe. 8. The fitting joint according to claim 3 is provided with means for preventing leakage of the water blocking filler according to claim 5,
The leakage prevention means is formed by filling the joint steel pipe on the side opposite to the side pre-filled with the viscoelastic filler with mortar, or by filling the half steel pipe provided in the joint steel pipe filled with mortar with mortar. A method for stopping water in a steel sheet pile joint part, wherein the method is provided so as to close the slit of the joint steel pipe. 9. A method for stopping water in a steel sheet pile joint according to claim 1, wherein a portion of a fitting joint such as a steel sheet pile or a steel pipe sheet pile that is cast in the ground projects from the ground. In addition to providing a means for preventing the viscoelastic filler from leaking from the slit of the steel, a means for preventing the joint portion from separating due to a tensile force acting on the joint portion is provided. How to stop water from the sheet pile joints. 10. The water stopping method according to claim 9, wherein
The steel sheet pile joint according to any one of 5 or 8 is subjected to the water stopping method, and the joint separation preventing means is parallel to the base of the T-shaped joint, and on one side or both sides of the large diameter portion of the joint steel pipe. The steel plate for mortar restraint is provided on the steel pipe sheet pile body steel pipe so as to be located at, from the engaging projection provided on the steel plate for mortar restraint, and the tension transmission key provided on the joint steel pipe so as to engage with this engaging portion. A method for stopping water in the constructed steel sheet pile joint. 11. The water stopping method according to claim 9,
5 or 8 is applied to the water stopping method of the steel sheet pile joint according to any one of claims 5 to 8, and the joint separation preventing means is parallel to the base of the T-shaped joint and on both sides of the large diameter portion of the joint steel pipe or The steel plate for mortar restraint is provided on the steel pipe sheet pile body steel pipe so as to be located on one side, and when the joint steel pipe moves in the joint separating direction, the large diameter portion of the joint steel pipe concerned is engaged with the steel pipe for mortar restraint. A method of stopping water in a steel sheet pile joint part including an engaging projection provided. 12. The method of stopping water in a steel sheet pile joint according to claim 1, wherein a blade-like portion is formed at a lower end of a T-shaped joint or a joint steel pipe which is a trailing side. A method of stopping water at a steel sheet pile joint. 13. The method for stopping water in a steel sheet pile joint according to claim 12, wherein the blade-like portion formed on the flange portion of the T-shaped joint and the lower end of the long claw-side fitting section of the joint steel pipe. A method for stopping water in a steel sheet pile joint part, wherein the blade portion is formed by a vertical surface and an inclined surface inclined in a direction away from the steel pipe sheet pile main body steel tube of the leading end as it goes upward.