JPS5855285B2 - Corrosion protection method for structures in bank protection work and corrosion protection cover used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for effectively imparting anti-corrosion treatment to structures used in revetment work for seashores, rivers, lakes, etc., and a corrosion-resistant cover used in carrying out the method.

It is inevitable that shore protection structures such as coasts, rivers, lakes, and marshes are affected by alternating wet and dry conditions due to fluctuations in water level.

It is well known that the parts of the seawall that are underwater and the parts that are above the water surface constantly change due to changes in the tide level and waves on the coast, mainly due to changes in the flow rate in rivers, and changes in water storage conditions in lakes and marshes. It is as follows.

On the other hand, structures for bank protection work mainly consist of sheet piles such as steel plates and driven members such as steel pipe piles, and the parts that are always above the water surface and the parts that are always underwater are relatively free from corrosion. Although this is not often the case, parts that are exposed to alternating wet and dry conditions are susceptible to oxidation and corrosion due to this.

For this reason, the bank protection function cannot be maintained over time unless some kind of anti-corrosion work is carried out in areas that exceed the area of fluctuating water levels.

For this corrosion protection work, plastic covers are mainly used, and the inherent corrosion resistance of plastics is utilized.

However, plastic itself does not have high strength against external impacts like steel plates and pipes, so fiber reinforced plastic (FR: FR) is generally used as a plastic for this type of corrosion protection.
(abbreviated as P) is used, and the reinforcing structure is usually provided using this.

The most commonly used structure in facilities using steel pipes, such as seawalls and pier supports, is a cylindrical F-shaped structure that extends beyond the upper and lower limits of the above water level fluctuation range.
The RP cover is fitted and positioned, an appropriate spacer is interposed in the gap with the steel pipe, and an appropriate measure against mortar flow is provided at the lower end of the cylindrical cover to prevent mortar from flowing between the steel pipe and the cover. is injected and filled, and this is solidified.

The corrosion protection method of the present invention also follows the example of this general corrosion protection structure for individual steel pipe piles, but it eliminates the gaps between the individually driven steel pipe piles and prevents seawalls from being damaged by waves, water currents, etc. The present invention provides a new method that helps to prevent parts from being scraped or collapsed, and is particularly useful for preventing steel pipe piles from being scraped or collapsing on the inner side of the rows of driven steel pipe piles, which are the main component of retaining walls. On the land side of the pile driving line, water that enters the inside of the driving line through gaps between rows of steel pipe piles will not erode or collapse the earth and sand that is retained by the steel pipe pile retaining wall, which is the main part of the seawall. This is a consideration.

Furthermore, in order to solve both of the objectives of corrosion prevention and prevention of erosion and collapse of earth and sand at once, the present invention uses a single type of cylindrical cover that can widely accommodate the conditions unique to the construction site and the advantages of construction work. The important feature is that it has been designed to overcome the construction conditions that require it, and the production process of preparing and transporting various types of cylindrical covers with different dimensions to the construction site, as well as the complexity of on-site work. It is something to improve.

The present invention will be explained in more detail from what is shown in the drawings below. Fig. 1 shows an example of a seawall in which steel pipe piles form a retaining wall in an ideal state.

In the figure, reference numeral 11 indicates driven steel pipe piles, and these are all driven with equal center spacing S. FRP cylindrical covers are fitted into each of these steel pipe piles 11. 12 have the same diameter R, each cylindrical cover 12 is in close contact with the adjacent cylindrical cover 12, and each steel pipe pile 11 and each cylindrical cover 12 are in close contact with each other.
A binding and solidifying material 13 such as mortar is injected and integrated between the walls, and as a result, there is room for seawater and water to enter from the water side W to the land side of the seawall after the corrosion protection work has been carried out. It is formed so that there is no

Therefore, in this case, the FRP cylindrical cover 12 to be prepared
Since the relationship R=S is given between the outer diameter R of the driven steel pipe piles 11 and the center-to-center spacing S of the driven steel pipe piles 11, it is necessary to prepare a large number of cylindrical covers with outer diameters corresponding to the driven spacing of the steel pipe piles. It is self-evident that this is sufficient.

The driven steel pipe piles that form the main part of the revetment are arranged at exactly equal intervals, so if the steel pipe piles 11 are constructed or are being constructed along the row lines of the steel pipe piles 11, In this case, it is possible to prepare a large number of one type of cylindrical covers 12 having the same diameter in advance and fit them onto each pile 11 so that there are no gaps between the cylindrical covers 12.

However, in reality, it is extremely difficult to drive steel pipe piles in such an ideal arrangement, or they are almost never completely driven, and the underground structure of the driven part is difficult to drive, and the piles are not easily driven into the rock bed. Other influences may cause asymmetric spacing.
It is something.

An extreme example of this is shown in FIG.

In actual construction work, such severe unequal spacing as shown in FIG. 2 does not occur, but this figure shows an extreme example to make it easier to understand the present invention.

In this case, as a result of the construction site conditions and unavoidable human errors due to construction work, the center spacing of each steel pipe pile 11 is S1〆S2/S3/... with respect to the originally intended driving interval S of the steel pipe piles 11.・・・・・・・・・・・・
In such a situation, it is not possible to uniformly determine the outer diameter of the corrosion-resistant cover 12 to be used.

Therefore, in the present invention, we have departed from the idea that conventional cylindrical covers were used for corrosion protection work, and have developed a cylindrical cover C having an elliptical or oblong cross-sectional shape having a major axis a and a minor axis.
I decided to adopt.

The details are shown in enlarged cross-sectional plan views in Figures 3A and 3B, but even in the case of collapse, the diameter passing the center varies depending on the direction, and the maximum diameter is a and the minimum diameter is b. It has a non-circular cross section.

In Fig. 3A and Fig. 3B, 22 is a cylindrical cover C.
is a cylindrical wall, 32 is integrally formed at the lower end thereof,
Alternatively, the bottom body 32 is attached as a separate body, and the bottom body 32 has a perfectly circular through hole 52 slightly larger than the outer diameter P of the steel pipe pile 11.

A sealing member 42 made of synthetic rubber or other elastic material and arranged in an annular or annular shape is bonded to the periphery of the through hole 52 by adhesive, bolting, or the like.

The inner diameter r of the seal member 42, the outer diameter P of the steel pipe pile 11,
The relationship with the hole diameter of the through hole 52 is as follows.

The cylindrical cover C having such an elliptical or oblong cross section has a through hole 52 in its bottom body 32 with a hole diameter slightly larger than the outer diameter P of the steel pipe pile 11.
If the fitting operation is carried out as usual, the fitting will be done without any difficulty, and it will be possible to rotate the steel pipe pile 11 as appropriate.

At this time, the seal member 42, whose inner diameter r is smaller than the outer diameter P of the steel pipe pile 11, is flipped up and curved at the same time as it is fitted, as shown in FIG. 4, to maintain close contact with the steel pipe pile 11.

FIG. 4 is a partially longitudinal front view showing a state in which the cylindrical cover 〇 of the present invention is fitted into two adjacent steel pipe piles 11.

The cylindrical cover 〇 is located in the height area H shown in Fig. 4 K>, with the highest limit of water level fluctuation indicated by WHL and the lowest limit indicated by WLL.
It is positioned so as to extend above and below the cylindrical cover C, and is supported by appropriate suspension or support means, for example, from the outside of the cylindrical cover C, or by being attached in advance to the upper edge of the cylindrical cover C. Support using a button hanging hook, steel pipe pile 11
The steel pipe pile 11 and the cylindrical cover C are integrally consolidated by injecting and filling a binding and solidifying material 13 such as mortar between the steel pipe pile 11 and the cylindrical cover C, but in the method of the present invention, this mortar etc. Prior to filling the binding and solidifying material 13, the cylindrical covers fitted into each steel pipe pile 11 are rotated around each steel pipe pile 11, and the cylindrical covers adjacent to each other are separated as shown in FIG. Position C so that they are in close contact with each other.

The part indicated by the symbol Q in FIGS. 2 and 4 is
This is a portion where adjacent cylindrical covers C2C contact each other along a perpendicular line.

In this state of mutual contact, an appropriate spacer 23 is interposed between each steel pipe pile 11 and the cylindrical cover C, and if necessary, an outer spacer is placed between each steel pipe pile 11 and the cylindrical cover C on the land side. Loosely embed earth and sand that will press against the cover to hold each cylindrical cover C so that its orientation does not change.

In this way, when the binding and solidifying material 13 such as mortar is injected and solidified, each steel pipe pile 11 and each cylindrical cover C fitted therein are integrally bound, respectively. The outer periphery of the portion of the steel pipe pile 11 that is exposed to alternating dry and wet conditions is covered with a corrosion-resistant cylindrical cover C made of plastic or the like, so that the steel pipe pile 11 is protected from corrosion over time. Then, the required bank protection work can be completed by carrying out full-scale filling of earth and sand behind the row line on the landward side of the row line of the constructed steel pipe piles 11 and performing ramming.

The figure shown is an example of bank protection construction.

In addition, although the method of the present invention has been illustrated to make it easier to understand, in actual construction work for seawall work, most of the construction work is done in rows on the landward side of the row line of the steel pipe piles 11. The steel pipe piles 11 are used as supports, and sheet piles are driven along the piles 11 to serve as earth retainers, and it is easy to see that the method of the present invention can be easily implemented even in such construction implementation mode. be understood.

According to the present invention, as is already clear from the view shown in FIG. 2 and the related explanation, the row lines of the steel pipe piles 11 do not line up exactly as they are driven. However, the driving interval S1 of each steel pipe pile 11
．． S2. Even if S3... are not aligned and are spaced unevenly, the cylindrical cover C fitted into each steel pipe pile 11 can be appropriately rotated along the outer wall of the steel pipe pile 11. The cylindrical covers C to be placed on the outside can be arranged in a row without gaps between each other, and this adjustment is performed so that the required driving interval S of the steel pipe piles 11 is between the major axis a and the minor axis. By selecting the cylindrical cover 〇 made in this manner, it is possible to carry out the process appropriately by utilizing the range of the difference between the major axis a and the minor axis a.

The cylindrical covers C arranged closely together enable the desired construction work to be carried out without creating gaps on the seawall surface, so water and waves that enter through the gaps can damage the land side of the rows of steel pipe piles L. This is extremely beneficial as it can prevent sediment from being washed away and banks from collapsing.

In the embodiment shown in FIG. 4, a wall is attached to the lower end of the cylindrical cover C so that the binding and hardening material 13 such as mortar to be injected is not washed away from the lower end of the cylindrical cover C. A bottom body 32 is provided integrally with the steel pipe pile 11.
A through hole 52 having a diameter slightly larger than the outer diameter P of the through hole 52 is formed, and an annular elastic seal member 42 is provided along the periphery of the through hole 52, and the seal member 420 has a normal inner diameter r.
Although the structure is such that the diameter P is slightly smaller than the outer diameter P of the steel pipe pile 11, this embodiment should not be interpreted as the only example of preventing the pouring and filling of the bonding and solidifying material 13, such as mortar, from being washed away.

FIG. 5 shows another example of the cylindrical cover C.

As can be seen from the cross-sectional plan view of the cylindrical cover C shown in the same figure and the partially longitudinal front view shown in FIG. This may be achieved by using the sealing member 62 in place of the bottom body 32 of the embodiment described above, as long as the ability to support the load is not lost.

The seal member 62 itself has a through hole 72 with an outer diameter slightly smaller than the outer diameter of the steel pipe pile 11, and the outer peripheral edge of the seal member 62 is directly joined to the inside of the cylindrical wall of the cylindrical cover C. has been done.

According to such a configuration, when the steel pipe pile 11 is fitted into the steel pipe pile 11, the peripheral edge of the through hole 72 is virtually flipped up, the diameter of the through hole 72 is expanded, and the curved seal member 62 is injected and filled. The binding and solidifying material 13 such as mortar is retained without being washed away.

As described above, according to the method of the present invention, both existing seawall structures and newly constructed seawalls can be constructed.
It is well suited for the unavoidable uneven spacing work of driving steel pipe piles, and can exhibit a corrosion-preventing function. In addition, corrosion-proofing work can prevent mud from washing away on the shore and collapse of the shore due to water entering between the piles. It often achieves the intended purpose and has many practical advantages.In particular, it is often possible to use one type of cylindrical cover instead of having to prepare several types of corrosion-proofing bars depending on the arrangement spacing of driven steel pipe piles. Therefore, it can be adapted to construction work.

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view showing an example of construction of a seawall construction, which illustrates an ideal example in which corrosion-protective cylindrical covers of the same diameter are applied to rows of steel pipe piles that have been driven under ideal conditions; Fig. 2 is a plan view showing an example of corrosion prevention work according to the present invention;
Figures A and 3B are enlarged cross-sectional plan views showing examples of corrosion-resistant cylindrical covers used in the method of the present invention, and Figure 4 is a longitudinal cross-sectional view of a part of the seawall structure in which the method of the present invention was implemented. FIG. 5 is an enlarged cross-sectional plan view showing another example of a corrosion-resistant cylindrical cover, and FIG. FIG. 11... Steel pipe pile, 12... Corrosion prevention cylindrical cover, 13
... binding solidifying material, - a... major axis, b... minor axis,
C... Corrosion-proofing cylindrical cover, D... Hole diameter of through hole 52,
L...land side, W...water side, Q...mutual contact part of cylindrical cover C, 22... cylindrical wall, 32... bottom body, 4
2... Seal member, 52... Through hole, 62... Seal member, 72... Through hole, S... Equal spacing of steel pipe piles 11, S1v S2 p S3... Steel pipe piles 11 Irregular intervals, P... Outer diameter R of steel pipe pile 11...
...Outer diameter of the corrosion-proof cylindrical cover, r...Inner diameter of the sealing member.

Claims (1)

[Scope of Claims] 1. For a revetment part where a large number of steel pipe piles are driven at irregular intervals or are driven in rows in asymmetric rows, A corrosion-resistant cylindrical cover with a non-circular cross section having a short diameter of A seawall construction work characterized by injecting and filling a binding material such as mortar between each steel pipe pile and each of the cylindrical covers fitted into each pile to solidify them together. Corrosion prevention method for structures. 2.For revetment areas where a large number of steel pipe piles are driven at uneven intervals or are driven in uneven rows, each steel pipe pile is inserted into the pile. A corrosion-resistant cylindrical cover, the cylindrical cover has a major axis and a minor axis, and is rotated around each steel pipe pile after the above-mentioned fitting, so that the cylindrical cover is connected to the adjacent fitting cylindrical cover. A corrosion-resistant cover for use in a structure for bank protection work, characterized in that it is configured so that it can be brought into close contact with each other without any gaps. 3. The corrosion-resistant cylindrical cover is provided with a bottom body at its lower end, and the bottom body is provided with a circular through hole having a diameter slightly larger than the outer diameter of the steel pipe pile into which it is to be fitted. Corrosion-prevention cover used for structures for bank protection work described in Section 1. 4. The corrosion-resistant cylindrical cover has a bottom body at its lower end, and the bottom body has a circular through hole with a diameter slightly larger than the outer diameter of the steel pipe pile to be fitted into, and the steel pipe to be fitted to the periphery of the hole. 3. A corrosion-protective cover for use in a structure for bank protection work according to claim 2, which is provided with an annular sealing material having an inner diameter slightly smaller than the outer diameter of the pile. 5. Claims in which the corrosion-resistant cylindrical cover is provided with an elastic bottom body at its lower end, and the bottom body is provided with a circular through-hole having a diameter slightly smaller than the outer diameter of the steel pipe pile into which it is to be fitted. Corrosion-proof cover used for the structure of the bank protection work described in paragraph 2.