JP7126883B2 - Steel cell structure and its construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a steel cell structure used for marine/port structures such as seawalls, dolphins, moorings, or land structures such as erosion control dams, and construction methods thereof.

General steel cells are mainly divided into steel plate cells and steel sheet pile cells. Steel plate cells are constructed by filling earth and sand into a steel outer shell consisting of cylindrical cells and arc-shaped arcs that connect them. There are embedded steel cells, which are pre-integrated cells that are driven into the ground of the seabed and filled inside, and steel steel cells, which are placed on the seabed ground and filled inside. It is used for bank protection structures. In addition, it is also used for erosion control dams. A steel sheet pile cell is constructed by assembling straight steel sheet piles in a circular or arc shape to form an outer shell.

The steel plate of the outer shell is a rational structure that resists the earth pressure with the tensile force, so it is a highly economical structure. Various inventions related to steel cells have been made, for example, the inventions disclosed in Patent Documents 1 to 5.

Patent Literature 1 describes a steel cell in which a plurality of steel members are arranged in series in the circumferential direction. Equipped with five or more steel members each having a longitudinal joint for connecting in the axial direction, and the steel members are provided continuously at predetermined locations in the circumferential direction, and each The longitudinal joints are all arranged at different axial positions.

Patent Literature 2 describes a method for installing a steel plate cell/arc that is divided into upper and lower parts. A cylindrical first copper plate that forms the first cell is driven into the ground along the axial direction of the barrel, the second cell is suspended from above the first cell, and the upper end of the first copper plate is placed on the inner peripheral surface or the outer peripheral surface. A tubular second copper plate forming a second cell is fitted to the connection member attached to the surface, the second cell is connected to the first cell, and the upper end of the first copper plate and the lower end of the second copper plate are connected. are joined by circumferential welding.

In Patent Document 3, cylindrical steel plate cells are provided in a plurality of steel plate cell-constituting units having divisions extending in the direction of the cylindrical axis, and in opposing portions of adjacent steel plate cell-constituting units, extending in the direction of the cylindrical axis. It is composed of a fitting joint.

Patent Literature 4 describes a segment joint for a steel sheet pile cell structure for constructing a steel sheet pile cell structure by collecting and connecting ends of a plurality of steel sheet pile segments.

Patent Document 5 describes a polygonal cylindrical cell composed of a guide pile and an element cell. Guide piles with joints on the left and right sides are driven into the submerged ground at predetermined intervals along the perimeter of the cell to be constructed, and element cells made of wide flat steel plates with joints on the sides are placed between the guide panels. The joint is engaged and driven into the waterbed ground.

JP 2017-061780 A Japanese Patent No. 5769608 Japanese Utility Model Laid-Open No. 60-091623 Japanese Patent Application Laid-Open No. 2001-152441 JP-A-10-054018

Technical Standards and Commentaries for Port and Harbor Facilities, Japan Port and Harbor Association, April 1999, Volume 2, pp.718, 726, 729 Yukio Saimura, Kiyohiro Morimoto, Yukinori Takase, On-site measurement results of embedded soil of steel plate cells, Summary of 36th Annual Conference of Japan Society of Civil Engineers, Part 3, pp.562-563, 1981

Conventional steel cells require large-scale production yards to be assembled into a cylinder before being driven into the seabed, and large construction machinery must be used for transportation and driving. . Since the diameter of the cell body becomes very large according to the required wall height, it also has the drawback of requiring a vast site and huge heavy machinery to assemble and store it.

Since the steel shell structure alone cannot withstand waves during construction, the steel shell structure is thin enough to ensure stability. It is necessary to. However, since circular cells are huge, it is difficult to fill them all at once.

Patent Documents 1 to 5 show various divided forms in the manufacturing process or transportation of steel cells. Especially, in filling the inside of the steel cell, the amount of filling at one time is enormous, and the steel cell receives a very large earth pressure from the filling material.

Non-Patent Document 1 states that the thickness of the steel cell should be determined based on the maximum horizontal tension acting on the cell shell, etc. On the other hand, in calculating the maximum horizontal tension generated in the arc, It is stated that if the ratio of the cell center spacing to the cell diameter is 1.5 or less, the fill soil pressure coefficient of the arc portion should be 1/2 of the cell body.

Under the background as described above, the present invention provides a steel cell structure that saves labor in heavy construction equipment, eliminates the need for a manufacturing yard, is excellent in economic efficiency and workability, and is structurally stable, and a steel cell. The object is to provide a construction method for a structure.

The present invention relates to a cylindrical steel cell structure filled with a filling material, wherein the steel cell is composed of an arc member having an arc-shaped horizontal cross section and a joint member connecting the arc members. and an outer arc member forming outer shells on the front side and the back side of the steel cell structure and an inner arc member partitioning the inside of the steel cell structure are used as the arc members, and the front side and the back side are used as the arc members. Cylindrical steel cells formed by the outer arc member and the inner arc member overlap each other between adjacent cylindrical steel plate cells, and the overlapped portions are adjacent cylindrical It is characterized by being a closed space sandwiched between adjacent inner arc members that constitute a steel cell.

In the steel cell structure of the present invention, in order to create a huge cell, the outer arc member and the inner arc member are combined, and the arc-shaped arc member and the joint member alone constitute a cylindrical steel cell. Adjacent cylindrical steel cells overlap each other, and the interior is partitioned by an internal arc member to reduce the earth pressure acting on the cylinder.

That is, in the conventional cell structure as well, as described in Non-Patent Document 1, the ratio of the center interval of the cell body to the cell diameter is 1.5 for the arc portion with respect to the cylindrical cell body. If it is below, it is said that the filling soil pressure coefficient should be 1/2 of the cell body, but in the structure of the present invention, the inside of the cylinder is partitioned by the internal arc member for the overlapped part , the earth pressure itself acting on the cylindrical portion is reduced.

In addition, if only the arc member and the joint member are used, the heavy equipment required for manufacturing is not so large, and the arc member can be stacked, so it does not require a large site for stock and is easy to transport. Furthermore, the conventional welding work is no longer necessary, and rapid construction is possible.

The outer arc member and the inner arc member are mainly made of arc-shaped steel plates, but they can be provided with stiffening ribs in the same way as conventional steel cells or arcs, so that they are structurally stable and economical. . Further, as with the conventional arc, by forming joint portions at both ends of the arc-shaped steel plate, the arc members can be directly connected to the joint members that connect the arc members.

In the steel cell structure of the present invention, the outer arc member and the inner arc member are sequentially connected via the joint member, and the interior is filled with the filling material, thereby forming a steel plate cell structure such as a revetment and a quay wall. things are built.

At this time, the parts surrounded by the outer arc member and the inner arc member are sequentially filled with the filling material, and the next arc member is connected, so that the construction is always progressed in a structurally stable state. be able to.

The construction method of the steel cell structure of the present invention relates to the construction procedure of the steel cell structure of the present invention as described above,
(1) a step of precedingly installing and fixing a plurality of joint members at the installation position of the steel cell;
(2) installing while sequentially connecting the outer arc member and the inner arc member between the joint members;
(3) sequentially filling the space defined by the outer arc member and the inner arc member with the filling material;
is repeated in sequence.

In construction, since the joint member serves as a guide member for the arc member, the joint member should be inserted first or placed, and then each arc member adjusted in arc length may be inserted in sequence.

Regarding the step (3) of sequentially filling the space partitioned by the outer arc member and the inner arc member with the filling material, there is a method of sequentially filling in one direction of the steel plate cell structure, A method of filling the closed space sandwiched between the internal arc members of the overlapping cells with the filling material to form the small islands prior to filling, and then filling the space sandwiched between the small islands on both sides. Conceivable.

In the former case, there is an advantage that the process is not complicated because the filling is performed sequentially in one direction. In the latter case, when the overlapped portion is filled first, the small island portion is filled with a small amount of filling material. Therefore, there is an advantage that the structure can be stabilized at an early stage.

ADVANTAGE OF THE INVENTION This invention consists of the above structures, and the following effects are acquired.

(1) Since the main structure consists only of the outer arc member, the inner arc member, and the joint member, each member can be stacked, making it easy to stock and transport. If only the arc members are used, the heavy construction equipment for constructing the steel cell does not have to be so large.

(2) Since the arc member and the joint member can be installed as they are on the seabed ground, there is no need to assemble them in advance unlike the conventional art, and a large-scale production yard is unnecessary. In addition, the welding work that was performed during large-scale assembly is eliminated, and quality control during welding is no longer necessary. These effects lead to labor saving of work, construction cost is suppressed, and as a result, total cost can be suppressed.

(3) A steel cell structure can be constructed simply by inserting or placing joint members that serve as guide members first, adjusting the arc length, and inserting each arc member in sequence. It becomes possible to construct a relatively stable steel cell more easily than before.

(4) Since the small islands surrounded by the internal arcs are present in the outer shell made up of the external arc members, the filling soil sandwiched between the small islands is constrained, so the earth pressure pushing out the external arcs is increased. As a result, the thickness of the arc plate can be reduced and the economy can be improved.

(5) The shear resistance of the steel cell wall is greater than that of a normal steel cell structure due to the two internal arc members in the islet.

(6) When the small island portion sandwiched by the inner arc portion is filled first, the amount of soil required for the small island portion at one time is small, and when the small island portion is first filled, stability can be achieved at an early stage. There are benefits to be gained.

BRIEF DESCRIPTION OF THE DRAWINGS The structure of the steel cell of this invention is shown roughly, (a) is a perspective view, (b) is a top view. (a) and (b) are plan views showing an embodiment of a joint member used in the present invention. (a) and (b) are plan views showing other embodiments of joint members used in the present invention. 1 is a perspective view showing a construction procedure in one embodiment of a steel cell structure construction method of the present invention. FIG. FIG. 5 is a perspective view showing a construction procedure following FIG. 4; FIG. 6 is a perspective view showing a construction procedure following FIG. 5; FIG. 7 is a perspective view showing a construction procedure following FIG. 6; FIG. 8 is a perspective view showing a construction procedure following FIG. 7; FIG. 9 is a perspective view showing a construction procedure following FIG. 8; FIG. 10 is a perspective view showing a construction procedure following FIG. 9; FIG. 11 is a perspective view showing a construction procedure following FIG. 10; FIG. 12 is a perspective view showing a construction procedure following FIG. 11; FIG. 13 is a perspective view showing a construction procedure following FIG. 12; FIG. 14 is a perspective view showing a construction procedure following FIG. 13; FIG. 15 is a perspective view showing a construction procedure following FIG. 14;

Specific embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a steel plate cell structure 1 according to the present invention, where (a) is a schematic diagram and (b) is a plan view.

In this embodiment, the steel plate cell structure 1 includes an outer arc member 2 forming outer shells on the front side and the back side, an inner arc member 3 partitioning the inside, and the outer arc member 2 and the inner arc member 3 being separated from each other. The main components are a joint member 4 to be connected and a filling material 5 filled inside.

The outer arc member 2 and the inner arc member 3 are basically structural members made of arc-shaped steel plates similar to the arc members in the conventional steel plate cell structure. Those with ribs are used.

In this embodiment, as shown in FIG. 1, two outer arc members 2 on the front side and the back side of the steel plate cell structure 1 and two inner arc members 3 drawing an arc continuous with the arc are provided. Cylindrical cells are formed through four joint members 4, and the adjacent cylindrical cells overlap at the inner arc member 3, and the planar shape sandwiched by the inner arc member 3 in the overlapped portion is A spindle-shaped closed space with a small cross-section is formed, and a closed space with a large cross-section with an hourglass-shaped flat cross-section is formed in a portion sandwiched between the closed spaces with the spindle-shaped small cross-section on both sides.

Therefore, each joint member 4 needs to connect the ends of the four arc members, and a cross joint 4a is used as the joint member 4 in the embodiment of FIG.

By filling the cells with the filling material 5, the steel plate cell structure 1 having the spindle-shaped closed space with a small cross-section becomes the small island portion 5a and the hourglass-shaped general portion 5b therebetween is constructed.

In such a configuration, the interior of the steel plate cell structure 1 is partitioned by the internal arc member 2, thereby reducing the earth pressure acting on the cylinder of the cell as described above.

FIGS. 2(a) and 2(b) each show an embodiment of the joint member 4 used in the present invention. The cruciform joint 4a shown in FIG. 2(a) may be, for example, one using a straight steel sheet pile. It can be manufactured by welding to

As shown in the figure, in the case of a cross joint 4a using straight steel sheet piles, the end portion has a general C-shaped joint shape, and the end portions of the inner arc member 2 and the outer arc member 3 are connected to the cross joint. If the cross joint 4a is formed in the same C-shape as 4a, the end of the inner arc member 2 or the outer arc member 3 can be connected simply by fitting the end of the cross joint 4a.

The arc joint 4b shown in FIG. 2(a) is obtained by welding a half-cut straight steel sheet pile 11 to an arc-shaped member 12. As shown in FIG. In the case of a joint using an arcuate member 12 as shown in the figure, the joint can be part of the arc.

FIGS. 3(a) and 3(b) respectively show other embodiments of the joint member used in the present invention.
A joint member 4c shown in FIG. 3(a) is obtained by welding straight steel sheet piles 11 cut in half at intervals of about 90 degrees to a steel pipe 13. As shown in FIG.

The joint member 4d shown in FIG. 3(b) is formed by welding an arc joint to the steel pipe 13 at intervals of about 90 degrees. A T-shaped joint formed at the end of 3 is fitted, and the gap is filled with mortar.

4 to 15 show the construction procedure in one embodiment of the construction method of the steel plate cell structure of the present invention.

First, in order to construct the first steel plate cell 1a, cruciform joints 4a with low wave resistance (small area hit by the fluid force of waves) are driven into the leveled seabed at four locations (Fig. 4 reference). Here, the cross joint 4a is shown as the joint member, but a frame formed by assembling a plurality of joint members may be sunk and grounded. Also, in the case of a placed cell, only the cross joint 4a needs to be embedded.

After installing the cruciform joint 4a, two outer arc members 2 and two inner arc members 3 are successively placed between the cruciform joints 4a (see FIG. 5), and the outside of one cylindrical steel plate cell 1a is placed. Build the shell (see Figure 6).

Next, in order to construct the second steel plate cell 1a, the cross joints 4a are placed at two locations (see FIG. 7). Then, two external arc members 2 and two internal arc members 3 are placed between the four cross joints 4a, including the two cross joints 4a placed when constructing the previous steel plate cell 1a. do.

One of the two inner arc members 2 will be cast inside the previously built steel plate cell 1 (see FIG. 8). As shown in FIG. 8, two steel plate cells 1a adjacent to each other are overlapped with each other via a closed space with a small cross section formed by being surrounded by the internal arc member 2. As shown in FIG.

After building up to the outer shell of the second steel plate cell 1a, the first steel plate cell 1a is filled (see FIG. 9). In the case of a procedure in which the small island portion 5a surrounded by the inner arc member 2 is first filled, the structure is stabilized at an early stage, the necessity of preparing a large amount of soil at once is eliminated, and workability is improved.

After filling the first steel plate cell 1, two cross joints 4a for constructing the third steel plate cell 1 are driven (see FIG. 10), and then the outer arc member 2 and the inner arc member 3 are placed. to construct the outer shell of the third steel plate cell 1a (see FIG. 11).

After that, the inside of the second steel plate cell 1a is filled (see FIG. 12). After that, the same work is repeated, and a plurality of steel plate cells 1a are stacked and constructed (see FIGS. 13 to 15).

As a construction procedure different from this, after constructing the cruciform joint 4a, two internal arcs are driven in advance, and the small island portion 5a surrounded by the two internal arc members 3 is filled. A small stable portion may be created and based on it the outer arc members 2 may be fitted in sequence and filled with soil.

In addition, it is necessary to consider the construction procedure considering the direction of the waves and the connection with the existing caissons.

DESCRIPTION OF SYMBOLS 1... Steel plate cell structure 1a... Steel plate cell (unit) 2... External arc member 3... Internal arc member 4... Joint member 4a... Cruciform joint 4b... Combined arc joint 4c... Joint member using steel pipe, 4c... Joint member using steel pipe, 5... Filling material, 5a... Small island part, 5b... General part,
DESCRIPTION OF SYMBOLS 10... Straight steel sheet pile, 11... Half-cut straight steel sheet pile, 12... Circular member, 13... Steel pipe, 14... L-shaped member

Claims (3)

A cylindrical steel cell structure filled with a filling material, wherein the steel cell is composed of an arc member having an arc-shaped horizontal cross section and a joint member connecting the arc members, and the arc member As the outer arc member constituting the outer shell on the front side and the back side of the steel cell structure and the inner arc member partitioning the inside of the steel cell structure, the outer arc member on the front side and the back side The cylindrical steel cells formed by and the inner arc member overlap each other between adjacent cylindrical steel cells, and the overlapped portions are adjacent cylindrical steel cells It is a closed space sandwiched between adjacent inner arc members that constitute a cell, and the outer arc member and the inner arc member are composed of the main arc-shaped steel plate and stiffening ribs that stiffen the arc-shaped steel plate. , joint portions provided at both ends of the arc-shaped steel plate as constituent elements . 2. The steel cell structure according to claim 1 , wherein said joint member is a joint member in which a joint portion is formed at each end of a steel material having a cross-shaped horizontal cross section. . A method for constructing a steel cell structure according to claim 1 or 2 ,
a step of precedingly installing and fixing a plurality of the joint members at an installation position of the steel cell;
installing the outer arc member and the inner arc member while sequentially connecting them between the joint members;
a step of sequentially filling a space defined by the outer arc member and the inner arc member with a filling material;
A method for constructing a steel cell structure, characterized by sequentially repeating

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