JP6241167B2 - Seismic reinforcement method for jetty - Google Patents

Description

The present invention relates to a seismic reinforcement method for a pier constructed on a quay or a revetment.

For example, a horizontal jetty is known as a mooring facility where a gantry crane is installed (see, for example, Patent Document 1). In such mooring facilities, it is common that the pier extending toward the earth retaining bank and the sea side is supported from below by a plurality of support piles.
And in the existing pier constructed based on the conventional seismic standards (for example, seismic intensity 5 weak), the horizontal resistance of the supporting pile is insufficient in the case of a large earthquake with seismic intensity 5 or higher. Reinforcement is performed.

  As a conventional general seismic reinforcement structure for a pier, as shown in FIG. 6, a pile driving machine 101 is arranged on an existing pier 100, and a plurality of additional piles 103 are newly added in addition to the existing pier support pile 102. The reinforcement which raises the earthquake-proof strength of the existing jetty 100 is performed.

Japanese Patent Laid-Open No. 2002-4241

However, in the conventional seismic reinforcement method for piers, when an additional pile is placed with a pile driver, the large pile driver will occupy the space on the existing pier during the placement work. There is a problem that the operation is restricted because the handling period such as a crane cannot be used during the work period and the operation stop period at the quay as described above occurs.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a quake-proof reinforcement method capable of performing quake-proof reinforcement work of a pier while suppressing restrictions on operation of a cargo handling facility such as a crane. To do.

To achieve the above object, the earthquake-proof reinforcement method of pier according to the present invention, meet pier Retrofit methods for reinforcing such a seismic intensity corresponding to existing pier is supported by the supporting piles set Intensity In addition, in the entire area below the existing pier, while maintaining fluidity during construction, it is solidified over time due to on-site curing, and an irregular aging solidified material that expresses a predetermined strength is the envy average located in the support pile The amorphous aging solidified material is placed so that a low tide level is buried, and is characterized by a uniaxial compressive strength that satisfies the formula (1) .

In the present invention, the amorphous aging solidification material is placed in the entire area below the existing pier, and the supporting pile supporting the existing pier is buried with the irregular aging solidification material to the desired average low tide level (LWL). By doing so, the horizontal proof stress of the support pile can be improved, and the seismic reinforcement of the existing jetty can be performed efficiently and reliably.

In this case, since the amorphous aging solidified material has fluidity at the time of construction, it can be driven by, for example, a pressure pump, and the pressure pump can be placed on a quay or a ship on the sea that is away from the existing jetty as a placement location. Thus, it is possible to perform construction in which an amorphous aging solidified material is pumped to the placement site by piping. For this reason, there is no need to place a large heavy machine such as a pile driver on the existing pier as in the conventional seismic reinforcement such as placing an additional pile, and there is an advantage that the heavy machine or the like does not occupy the existing pier. Therefore, it is possible to use the existing jetty even during the placement work of the irregular aging solidification material, so that the suspension period of the cargo handling equipment operation at the jetty can be shortened, and the suspension period of the crane can be shortened. It becomes possible.

Further, in the present invention, the uniaxial compressive strength of the amorphous aging solidified material is reinforced by the strength calculated based on the above formula (1), whereby the horizontal proof stress can be obtained with respect to the design seismic intensity. Become.

Moreover, in the seismic reinforcement method for a pier according to the present invention, it is preferable that the amorphous aging solidified material is a modified soil of mud.
In particular, the modified soil of the mud is more preferably a cement-based solidified material, a lime-based solidified material, or steelmaking slag added to the mud.

  In this case, it is possible to use modified soil made by mixing cement-based solidified material or lime-based solidified material and steelmaking slag into mud as an irregular aging solidified material. For example, dredged soil can be used as mud. Therefore, since the disposal cost of dredged soil is not required, the construction cost can be reduced.

According to the quake-resistant reinforcement method of the pier of the present invention, it is not necessary to arrange a large heavy machine that occupies the existing pier by the method of placing an amorphous aging solidification material, so that the operation of the cargo handling facility can be suppressed and There is an effect that the seismic reinforcement work can be performed.

It is a longitudinal cross-sectional view which shows the existing jetty reinforced using the earthquake-proof reinforcement structure of the jetty by embodiment of this invention. It is a figure which shows the result of having calculated the required intensity | strength of the amorphous aging solidification material in case the water depth is 4.5 m. It is a figure which shows the result of having calculated the required intensity | strength of the amorphous aging solidification material in case the water depth is 14.5m. It is a figure which shows the result of having calculated the required intensity | strength of the amorphous aging solidification material in the case of water depth 20m. It is a longitudinal cross-sectional view which shows the construction state by the earthquake-proof reinforcement structure of this Embodiment. It is a longitudinal cross-sectional view which shows the construction state by the seismic reinforcement structure of the conventional jetty.

Hereinafter, with the earthquake-proof reinforcement method embodiments according to the pier of the present invention will be described with reference to the drawings.

FIG. 1 shows a state where an existing pier 1 is reinforced using the quake-proof reinforcement method of the pier of this embodiment. The seismic reinforcement structure of the pier according to the present embodiment is a structure for reinforcing the existing pier 1 constructed on the quay 2 so as to have a predetermined seismic strength.
Here, in the following description, the direction toward the sea across the quay 2 is referred to as the sea side, and the direction opposite to the sea side is referred to as the land side. Moreover, the direction (direction orthogonal to the paper surface in FIG. 1) extending along the coastline is referred to as the extension direction.

The quay 2 includes a revetment steel sheet pile 21 provided along the extension direction, and a crane foundation support pile 22 that is placed at a predetermined interval in the extension direction on the land side spaced apart from the revetment steel sheet pile 21. A coping 23 that is driven by involving the pile head of the crane foundation support pile 22, a preparatory work 24 that is placed in the ground at a distance from the revetment steel sheet pile 21 on the land side, and a revetment steel sheet pile 21. The tie rod 25 which connects the upper end part 21a side and the laying work 24, and the roadbed 26 provided between the revetment steel sheet pile 21 and the coping 23 is provided.
A movable gantry crane or the like (not shown) is installed on the quay 2, and a moving rail (not shown) for the crane is laid in parallel on the existing pier 1 and the coping 23 along the extending direction. ing.

  The existing pier 1 extends and extends a predetermined distance from the revetment steel sheet pile 21, and the projecting portion of the existing pier 1 is supported from below by a plurality of pier support piles 11. The existing jetty 1 is a concrete plate-like body having a predetermined thickness, and is connected to the roadbed 26 via a bridge plate 27.

  For example, a steel pipe pile is used as the pier support pile 11 and is placed on a support ground on the seabed.

  A plurality of tie rods 25 are arranged at intervals along the extending direction, and each tie rod 25 is arranged at a predetermined depth from the ground surface.

  The code | symbol 3 of FIG. 1 has shown the amorphous aging solidification material cast | placed as a reinforcement part. The amorphous aging solidification material 3 is placed so that the pier support pile 11 is buried up to a mean water level (LWL). The amorphous aging solidifying material 3 is a material that maintains fluidity at the time of construction and solidifies over time by on-site curing and exhibits a predetermined strength. The thing which added the lime type solidification processing material or the steelmaking slag to the mud is mentioned.

The amorphous aging solidified material 3 is in a state where it has been solidified and exhibits a predetermined strength or in a state before solidification (including fresh concrete).
In addition, the modified soil is a material obtained by adding a solidification material (cement, lime, steelmaking slag) to mud soil among the amorphous aging solidification materials.

Here, a method for calculating the required strength of the amorphous aging solidified material 3 for obtaining the reinforcing effect will be described.
The required strength of the amorphous aging solidified material obtained by calculation when the water depth is changed to 4.5 m, 14.5 m, and 20 m is shown in FIGS.
As shown in FIG. 1, the horizontal force acting on the existing pier 1 during an earthquake changes depending on the seismic intensity, and when the seismic intensity increases, the acting horizontal force increases. Moreover, when the water depth of the pier 2 is deep, since the protrusion length of the pier support pile 11 becomes long, the horizontal resistance of the pier support pile 11 falls. Therefore, the horizontal force acting on the existing pier 1 depends on the design seismic intensity, and the horizontal resistance held by the pier support pile 11 depends on the water depth. Therefore, the required strength of the amorphous aging solidification material 3 depends on the design seismic intensity and the water depth. become.

  From the above relationship, the strength required for the amorphous aging solidified material 3 can be expressed by the equation (1) using the calculation result when the water depth is changed.

In the case where the design water depth shown in FIG. 2 is 4.5 m and the specifications of the pier pile (corresponding to the pier support pile 11) and the pile diameter φ is 700 mm and the plate thickness t is 12 mm, the magnitude of seismic motion is not increased in the unreinforced case. If it is 180 gal (design horizontal seismic intensity is 0.18), it can withstand the horizontal force generated by the design seismic intensity even if there is no reinforcement with an amorphous aging solidified material (judgment: OK). Under the same conditions, if the magnitude of the seismic motion is 250 gal (design horizontal seismic intensity is 0.25) in the unreinforced case, the horizontal strength is insufficient for the design seismic intensity (determination: NG). Under the same conditions, if the magnitude of the seismic motion is 250 gal (design horizontal seismic intensity is 0.25) in the case of reinforcement with the amorphous aging solidified material, the uniaxial compressive strength of the amorphous aging solidified material is By performing reinforcement with 100 kN / m ² calculated based on the equation (1), a structure capable of obtaining a horizontal proof stress with respect to the design seismic intensity is obtained (determination: OK). In addition, the uniaxial extrusion strength of the amorphous aging solidified material in FIG. 2 is 94.5 kN / m ^{2 with} the result of 300 × (0.25−0.18) × 4.5 in the equation (1) being 100 kN. / M ² .

Moreover, when the design water depth shown in FIG. 3 is 14.5 m, the case where the design water depth shown in FIG. 4 is 20 m is based on the equation (1) as in the case where the design water depth shown in FIG. 2 is 4.5 m. The uniaxial compressive strength of the amorphous aging solidified material can be calculated. Specifically, when the design water depth of FIG. 3 is 14.5 m, the uniaxial compressive strength of the amorphous aging solidified material is as described above under the pier pile specifications where the pile diameter φ is 1100 mm and the plate thickness t is 19 mm. By performing the reinforcement with 310 kN / m ² calculated based on the equation (1), a structure capable of obtaining a horizontal strength against the design seismic intensity is obtained (determination: OK). In addition, when the design water depth in FIG. 4 is 20 m, the uniaxial compressive strength of the amorphous aging solidified material is expressed by the above formula (1) under the condition that the pile diameter φ is 1600 mm and the plate thickness t is 25 mm. By performing the reinforcement with 420 kN / m ² calculated based on the structure, a horizontal proof stress can be obtained with respect to the design seismic intensity (determination: OK).

Next, the quake-proof reinforcement method of the pier of this Embodiment and the effect | action based on implementing this quake-proof reinforcement method are demonstrated in detail using drawing.
First, as shown in FIG. 5, the earth retaining steel sheet pile 5 is driven into the sea with a gap from the pier support pile 11 to the sea side, and is closed between the earth retaining steel sheet pile 5 and the seawall steel sheet pile 21 of the quay 2. Region R is formed.

  Next, the amorphous aging solidifying material 3 is applied below the existing jetty 1 by placing an amorphous aging solidifying material in the closed cut region R formed. Specifically, a pressure-feed pump 6 for sending an amorphous aging solidified material having fluidity at the time of construction is arranged further on the land side than the crane support pile 22 of the quay 2, and a pipe 7 is connected to the pressure-feed pump 6. Thus, the amorphous aging solidified material is pumped to the closed region R which is the placement site. In addition, the irregular aging solidification material thrown into the pressure pump 6 is mixed with mud and cement solidification treatment material or lime solidification treatment material or steelmaking slag as described above at a place different from the construction place. You may make it convey the made modified soil to the pressure feed pump 6, and may make it mix just before injection | throwing-in in the installation location of the pressure feed pump 6. FIG.

Subsequently, the amorphous aging solidified material charged into the pressure feed pump 6 is pumped toward the closed region R, and the amorphous aging solidified material is placed in the inner closed region R using the retaining steel sheet pile 5 as a mold. Fill. At this time, the seawater that has accumulated in the closed region R along with the filling of the amorphous aging solidified material flows over the earth retaining steel sheet pile 5 into the sea.
As shown in FIG. 1, the amorphous aging solidified material filled up to a predetermined height in the closed region R is solidified, and the amorphous aging solidified material 3 is placed at the upper end of the pier support pile 11. W. As a result, the seismic reinforcement work for the existing jetty 1 according to the present embodiment is completed.
The earth retaining steel sheet pile 5 may be left together with the modified body 3.

  Note that the method for placing the amorphous aging solidifying material 3 is not limited to the method of disposing the pump 6 on the quay 2 as described above. For example, when dredging work is performed near the sea at the same time as the seismic reinforcement work for the existing jetty 1, a well-known mixed solidification method in the pipe using the dredged soil can be employed. That is, a method may be used in which a solidification material is added to the kneaded material and kneaded in the tube in the middle of the pressure feeding pipe for sending the kneaded material to the placement site, and the modified soil is cast from the discharge port.

Thus, in the seismic reinforcement method of the pier according to the present embodiment, the amorphous aging solidification material 3 is placed in the entire lower part of the existing pier 1, and the pier support pile 11 that supports the existing pier 1 is attached to the L.P. W. By embedding with the amorphous aging solidified material 3 solidified to L, the horizontal strength of the pier support pile 11 can be improved, and the existing pier 1 as a whole can be efficiently and reliably reinforced with earthquake resistance.

In this case, as in the present embodiment, the amorphous aging solidification material can be driven by the pumping pump 6, and the pumping pump 6 is placed on the quay 2 away from the existing pier 1 or the ship on the sea, which is the driving site. It is possible to perform the construction in which the amorphous aging solidified material is pumped to the placement site by placement and piping. Therefore, it is not necessary to arrange a large heavy machine such as a pile driver on the existing pier 1 as in the conventional seismic reinforcement such as placing an additional pile, and the existing pier 1 is not occupied by a heavy machine.
Therefore, since the existing pier 1 can be used even during the placement work of the amorphous aging solidification material, the suspension period of the cargo handling equipment operation at the existing pier 1 can be shortened, and the crane suspension period Can be shortened.

  Further, in the present embodiment, a modified soil obtained by mixing a cement-based solidified material, a lime-based solidified material, or steelmaking slag with mud can be used as the irregular aging solidified material. Since soil can be used, in this case, the disposal cost of dredged soil becomes unnecessary, and the construction cost can be reduced.

In the quake-proof reinforcement method according to the present embodiment described above, it is not necessary to arrange a large heavy machine that occupies the existing pier 1 by the method of placing the amorphous aging solidification material 3, so that the operation of the cargo handling equipment is restricted. There is an effect that the seismic reinforcement work of the pier can be performed while suppressing the above.

As mentioned above, although embodiment of the earthquake-proof reinforcement method of the jetty by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the embodiment described above, the modified soil as the amorphous aging solidification material is a material obtained by adding cement-based solidification treatment material, lime-based solidification treatment material, or steelmaking slag to mud, The material is not limited and, for example, a material that does not contain mud such as concrete can be used as the amorphous aging solidification material.

  Moreover, it is not limited to structures, such as the shape of the existing pier 1, the diameter size of a pier support pile 11, and a number. For example, in the present embodiment, the overhanging portion of the existing pier 1 is supported from below by four pier support piles 11, but may be four or more or four or less depending on the pier overhang length. .

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Existing jetty 2 Quay wall 3 Amorphous aging solidification material 5 Earth retaining steel sheet pile 6 Pumping pump 11 Pier support pile 21 Revetment steel sheet pile 22 Crane foundation support pile G Ground R Closed area

Claims (3)

A quake-proof reinforcement method for a pier for reinforcing an existing pier supported by a support pile so as to have an earthquake-proof strength corresponding to a set seismic intensity,
In the entire lower area of the existing pier, while maintaining fluidity during construction, it is solidified over time by on-site curing, and an irregular aging solidified material that expresses a predetermined strength is the envy average low tide level located in the support pile Was laid to be buried,
The quake-resistant reinforcement method for a pier, wherein the amorphous aging solidified material has a uniaxial compressive strength that satisfies the formula (1) .

The method for seismic reinforcement of a pier according to claim 1 , wherein the amorphous aging solidification material is a modified soil of mud. The method for seismic reinforcement of a pier according to claim 2 , wherein the modified soil of the mud is a cement-based solidified material, a lime-based solidified material, or steelmaking slag added to the mud.

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