JPS63103112A - Steel jacket quaywall - Google Patents

Abstract

PURPOSE:To stabilize a quaywall at great water depth by a method in which auxiliary holding members are attached in parallel to the inside of a horizontal brace facing the water side of a steel jacket, and sheet piles are set between the vertical parallel members to fix them to the bottom ground under water. CONSTITUTION:Sheet pile-holding auxiliary members 16 are set in parallel on the inside of a brace on the water side of a steel jacket consisting of jacket legs 15a and horizontal braces 15b, and a sheet pile 17 is set between the members 16 and 15b. The assembled jacket is vertically lifted up on a predetermined place and settled on a given place of the seabed ground. Steel tubular piles are driven through the legs 15a to a given position into the ground and the sheet pile 17 is driven to a given setting position. The back side of the jacket 15 is embedded with soil and reinforced concrete is placed to the top of the jacket 15 as needed. The quaywall at great water depth can thus be stabilized.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention uses a steel jacket installed on the bottom of the water or on the seabed ground as a temporary material during the construction of sheet piles, and after construction as a permanent structural material for stabilizing the sheet piles. Regarding the quay.

``Conventional technology'' The quay made of sheet piles is designed to safely support the sheet piles.
There are those shown in Figure axd.

That is, i) It is a normal sheet pile type (Figure a), after driving a vertical sheet pile 1 in the front and partially filling in the back with earth and sand 2a,
Construct tie rods 3 and buttresses 4, and reclaim the remaining 2b
something that completes.

ii) A self-supporting sheet pile type (Figure b) with vertical steel pipe sheet piles 5 driven into the front and the back filled with earth and sand 6.

iii) In the diagonal pile sheet pile type (Fig. 0), the diagonal piles 7 are used instead of the tie rods 3 in the normal sheet pile type (Fig. a).
The pile is driven on the back side, and the 8 head of the sheet pile and the 7 head of the inclined shaft are connected to form a set of piles, and the horizontal displacement of the sheet pile 8 is restrained.

iv) In the double sheet pile type (Fig. d), sheet piles 9 and 10 are set in two rows at intervals, and the two rows of sheet pile heads are tied together with tie rods 11.
The inside is filled with earth and sand 12.

Above, on the quay shown in Figure a w d, the tilting of the top of the sheet pile 1 toward the water side due to the load applied to the quay is as follows in Figure a.
This is prevented by the back anchor effect of the tie rods 3 and buttresses 4, and in figure B, the tA pipe sheet pile 50 has great self-supporting rigidity, making the back anchor material unnecessary and prevented, and in figure C, it is prevented that the back anchor material is unnecessary. The piles 7 act as bank anchors to prevent this, and in Figure d, the tie rods 11 and the sheet piles 10 act as back anchors to prevent this.

``Problems to be solved by the invention'' However, in all of the above cases, due to the constraints of stress and displacement that occur in the sheet piles after the quay is completed, the problem in figure a is shallower than the water depth of about Ion, and the figure in figure b is shallower than about Ion. In Figure C, it is shallower than 5 to 6 m, in Figure C, it is shallower than 6 to 7 m, and in Figure d, it is shallower than 10 m.
Restricted to seawater.

In addition, prior to the construction of the sheet piles, it is necessary to perform temporary construction such as guides, and the sheet piles shown in Figure a require a long offshore construction period because they cannot be reclaimed until the tie rods and buttresses are completed. Without backfilling or buttresses after driving, there are disadvantages such as being vulnerable to waves, and in the case of the type shown in Figure b, the cross section of the sheet pile becomes extremely large if stability is to be ensured. The problem is that the displacement of the top of the sheet pile due to overburden loads, earthquakes, etc. is large, and the design method for the one shown in Fig. C has not been established and there are many unknown points. Each of these has the disadvantage of being vulnerable to waves in the absence of earth and sand.

``Means for Solving Problems'' and ``Operations'' The present invention was made in view of the above circumstances, and its gist is that it is a jacket leg that has already been established as a foundation material for constructing underwater structures. A steel jacket consisting of a three-dimensional structure of members such as horizontal braces has auxiliary clamping members added in parallel to the inside of the horizontal brace facing the water side, and sheet piles are inserted and installed in the gaps between the upper and lower parallel members. When the sheet pile is installed and fixed, and earth and sand is reclaimed on the back side of the sheet pile, the jacket serves as a temporary support and driving guide when constructing the sheet pile, resulting in simple and quick construction.
After reclamation, the horizontal brace facing the water side serves as a restoring material for the sheet pile, and the horizontal brace extending to the back of the quay and the jacket leg that connects to the horizontal brace perpendicular to the horizontal brace serve as the entire vertical length of the sheet pile. It is a permanent structural material that serves as a multi-stage bank anchor over a long period of time, making it possible to construct at great depths of water, making it possible to make sheet piles more economical, and further eliminating the need for the post-process of adding back anchors to sheet piles. be.

"Example" This will be explained in detail below based on construction procedure diagrams.

In other words, as shown in Figure 1, the seabed ground 13 at the planned location of the wharf construction site is dredged as necessary, and the soft soil is removed by sandwork 4.
to make the surface flat.

Note that if the seabed ground is of good quality and there is no risk of sliding failure or uneven settlement when the back of the seawall is filled with earth and sand, the above-mentioned dredging and replacement with sand 14 are not necessary.

On the other hand, on land, as shown in Figure 2, a tower-shaped three-dimensional structure consisting of members such as jacket legs 15a and horizontal braces 15b, which have already been established as foundation materials for constructing underwater structures, is used.
In the jacket 15 made by No. 1, there are auxiliary members 16 for holding sheet piles inside the horizontal braces at each level facing the water side.
... is added in parallel, and the parallel member 15b
A sheet pile panel 17 is installed across the upper and lower gaps of , 16.

One end of the sheet pile panel 17 remains near the bottom end of the jacket 15, and the other end protrudes near the top end of the jacket 15 or above it.

The members 15b and 16 serve as driving guides for the sheet pile panel 17, and also serve as restoring against soil pressure and wave pressure.

The connection between members 15b, 16 and sheet pile 17a is shown in Figure 3~
This is shown in detail in FIG.

That is, as shown in FIG.
It is temporarily fixed by 8.

In the figure, reference numeral 19 denotes a joint for connecting the sheet pile and the jacket leg, which is driven over almost the entire length in the tube axis direction of the jacket leg 15 facing the water side.

Figure 4 shows a U-shaped steel sheet pile 1 on a straight horizontal brace 15b.
7a, and Figure 5 shows a curved horizontal brace 1.
5b shows an example using a steel pipe type steel sheet pile 17a.

When using the U-shaped steel sheet piles shown in Figure 4, in order to disperse the earth pressure acting on the sheet piles and transmit it to the horizontal braces for uprighting,
The metal fittings 20 are connected to the horizontal brace by welding or bolts before inserting the sheet piles.

The fitting 20 secures an appropriate gap between the end plate 20a at the free end and the member 16 when attached to the horizontal brace, making it easy to insert and drive the sheet pile, and after the wharf is completed, it can be attached to the sheet pile such as a tonosho. It should be in close contact with the sheet pile web so that the applied load can be evenly transmitted to the horizontal brace.

In the case of Fig. 5, the horizontal brace 15b facing the water side is curved concavely, but this is due to the fact that the active earth pressure is large, such as when the water depth in front of the quay is large or the load from reclaimed excavation is large. Since the brace is required to have an extremely large cross section, it is curved concavely to reduce the bending moment and to make the cross section economical.

The completed jacket is shown in FIG.

In this jacket, as shown in detail in FIG. 7, the direction of the additional horizontal brace 21 and the jacket leg 15 are
By matching the direction of action of the resultant force R of the horizontal forces acting on a, the horizontal force acting on the jacket can be dispersed over the entire jacket.

P in the figure indicates earth pressure.

In addition, in the present invention, as described above, the sheet pile panels 17 are supported by the jacket 15, so the inclination of the sheet piles reduces the active earth pressure acting on the quay wall, and the construction cost of the entire quay wall including the jacket is minimized. However, if the angle of inclination is about 30° or less with respect to the vertical, the efficiency and difficulty of the sheet pile driving work are not much different from those for vertical sheet piles.

The jacket 15 assembled as described above is loaded onto a barge 22 as shown in FIG. 8, and towed by a tugboat 23 to a planned installation location.

Next, as shown in FIG. 9, the steel jacket 15 is lifted vertically using a marine crane 24 and is deposited at a predetermined position on the seabed 113 or replaced sand 14.

The figure shows an example where it is deposited on replacement sand 14.

Further, a steel pipe pile 25 is driven through the leg 15a of the jacket with a pile driver 27 until its lower end reaches a predetermined position on the support layer 26.

As shown in FIG. 10, the inner surface of the leg 15a and the steel pipe pile 25
Cement mortar is injected into the annular portion 28 consisting of the outer surface of the leg 15a and the steel pipe pile 25 to be integrated. still,
At this time, if the required length of the sheet pile is greater than the length of the leg, the temporary bead 18 described above is removed by gas cutting or the like, and then the sheet pile is driven into a predetermined insertion position using a hammer.

FIG. 11 shows the treatment of the sheet pile joint in the case of FIG. 5 described above.

As shown in the figure, earth and sand inside the joint 19 of the leg 15a and the joint 29 of the sheet pile 17a are removed using a water jet or the like, and a water stop agent such as cement mortar 30 is injected.

As shown in FIG. 12, the back of the jacket 15 is covered with dirt 31.
Reinforced concrete 32 will be constructed at the top of the jacket as necessary.

The horizontal brace and tonosho distribution hardware exposed to the atmosphere at the top of the jacket are connected to the steel sheet pile by welding or the like.

In addition, if it is necessary to suppress the horizontal displacement and generated stress of the jacket due to Tonosho water pressure, etc. to below a certain value, if the horizontal brace included on the reclaimed soil side of the jacket is treated in the same way as the water side and sheet piles are attached, Effects similar to those shown in FIGS. 13a and 13d can be expected.

Following the same procedure, install the jacket on the outer surface of the already installed jacket leg with a gap of the width of one sheet pile, and then insert the sheet pile between adjacent jacket legs by engaging them with the joints attached to the legs. , hammer into place, and repeat the process of pouring crown concrete on top of the jacket as necessary.

As a result, an extremely stable quay wall capable of coping with large water depths is completed, which is supported by multi-stage back anchors spanning the entire vertical length.

"Effects of the Invention" The various effects that can be achieved by the quay of the present invention are listed below.

The purpose is to devise a construction method with the following features.

i) Can be constructed even in deep sea areas of -20m to -30m.

ii) Since the righting can be installed in multiple stages from near the seabed surface to between the tops of the jackets, the cross-sectional force of the sheet piles is reduced, allowing the sheet piles to have an economical cross-section.

iii) Since the sheet piles and the joints of the sheet piles and the joints attached to the jacket legs are engaged with each other in advance and inserted into the restoring, there is great resistance to waves during construction.

iv) Since a backing is attached to the jacket and the sheet pile is inserted using it as a guide, it is necessary to construct temporary works such as guides and guide support piles before driving the sheet pile, as with conventional sheet pile quays. There is no.

■) In the case of conventional sheet pile type quays, except for the free-standing type, tie rods and support works are required, which involves driving the sheet piles, burying the back of the sheet piles, installing tie rods, and constructing support works. These operations are unnecessary.

vi) For the reasons mentioned in iii) to V) above, according to this construction method, the offshore construction period is short, so it is possible to construct a quay even in sea areas where there are few calm days.

vi) The design method for jacket structures that receive external forces has been established, and it is possible to construct highly reliable quay walls.

viii) The joints of the sheet piles inserted into the gap between the jacket restings are securely engaged with each other up to the bottom edge of the jacket, so even when installing the jacket, the sheet pile joints will not engage even if the sheet piles are driven into the specified position with a rear hammer. It is almost impossible for it to come off.

Therefore, it can also be applied to cases where it is necessary to reliably prevent the leakage of harmful substances from backfills, such as in waste treatment plants.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of maintenance of the quay construction ground, Fig. 2 is an explanatory diagram of preliminary processing of the steel jacket used in the present invention, Figs. 3 to 5 are enlarged cross-sectional views taken along arrow A-A in Fig. 2, FIG. 6 is a vertical view of an example of a steel jacket used in the present invention, FIG. 7 is an explanatory diagram of stress treatment of the steel jacket of FIG. 6, and FIG. 8 is an explanatory diagram of towing in the present invention. FIG. 9 is an explanatory diagram of sinking, FIG. 10 and FIG. 11 are explanatory diagrams of integral connection of joint parts, FIG. 12 is an explanatory diagram of reclamation, and FIGS. 13a to 13 are explanatory diagrams of a conventional quay. 1... Sheet pile, 2a... Earth and sand, 2b... Landfill, 3... Tie rod, 4... Buttress, 5...
・Steel pipe sheet pile, 6... Earth and sand, 7... Oblique pile, 8...
・Sheet pile, 9...Sheet pile, 10...Sheet pile, 11...
・Tie rod, 12... Earth and sand, 13... Seabed ground, 14... Sand, 15... Steel jacket, 1
5a... Jacket leg, 15b... Horizontal brace, 16... Auxiliary member, 17... Sheet pile panel, 17a... Sheet pile, 18... Weld bead, 1
9...Joint, 20...Metal fitting, 20a...End plate, 21...Horizontal brace, 22...
barge, 23...tugboat, 24...maritime crane,
25... Steel pipe pile, 26... Support layer, 27...
・Pile driver, 28... Annular part, 29... Joint,
30...Cement mortar, 31...Earth and sand, 3
2...Reinforced concrete. Z? F Δδ IQ 511 Bu ← 4v Force 4 ? ? 1 q Zutsu & e Ka retro

Claims (3)

[Claims] (1) A supporting member for clamping is added in parallel to the inside of the horizontal phrase facing the water side of a steel jacket consisting of a three-dimensional structure of members such as jacket legs and horizontal braces, and sheet piles are inserted in the gap between the above and below parallel members. A steel jacket quay characterized by being installed and fixed on the underwater ground and filled with earth and sand on the back side of the sheet pile. (2) The steel jacket quay according to claim 1, wherein the horizontal brace facing the water side of the steel jacket is curved concavely. (3) The steel jacket quay according to claim 1, wherein the steel jacket is also subjected to sheet pile attachment treatment on the reclaimed soil side.