JP3459917B1 - Composite caisson structure and method of constructing composite caisson - Google Patents

Abstract

【wrap up】 PROBLEM TO BE SOLVED: To provide a composite case comprising a concrete part and a steel part.
Song,Detachable steel partsComplex caisson structure
provide. SOLUTION: A blade port 12 is provided above the blade port 12.
Concrete skeleton 14 and concrete skeleton 14
Can be removed by connecting multiple steel sheet piles above the cylinder
In a composite caisson structure having a
Predetermined spacing on top of concrete frameIn concrete
A cylindrical socket portion 16 erected on the upper surface of the frame portion 14 is provided.
The steel sheet pile 18 is inserted into the socket 16
The steel part 21 is formed by connecting the steel sheet piles 18 in close contact with each other.
After completion, the anchor 20a embedded in the socket 16
The connected rod 20c is held at the upper end of the steel sheet pile 18 with a closed section.
By tightening with the pressing bolt, the steel part 21 is
Detachably presses on concrete skeleton 14Composite type
It is a Johnson structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite caisson in which a caisson is combined with a closed section steel sheet pile, and a composite caisson in which a closed section steel sheet pile is detachably combined with a concrete caisson.

[0002]

2. Description of the Related Art Conventionally, caisson construction methods such as open caisson and pneumatic caisson have been widely used in civil engineering works such as foundation works. Depending on the conditions of the construction site, it is often found that the caisson must be submerged deep in the ground. When the caisson is submerged deep in the ground like this, a pneumatic caisson is used. Pneumatic caisson is a construction method in which compressed air is sent to the space of the blade edge to excavate the ground and sink the caisson.
Pneumatic caisson requires various facilities related to the supply of compressed air, which increases equipment costs and requires working under high pressure air, so the working hours of workers are strictly defined by law. Therefore, the construction efficiency is not always good.

In order to construct deeply into the ground by the open caisson method, a temporary wall 110 is formed on the upper end side of the caisson 100 with steel sheet pile or reinforced concrete (not shown) as shown in FIG. Bracket 13 on the inner surface
The caisson 100 has been constructed while a reinforcing material such as 0, a truss 140, and an upset 150 is arranged, and the side wall surface of the excavation hole is stabilized by the temporary wall (for example, see Non-Patent Document 1).

[0004]

[Non-Patent Document 1] Hokuriku Regional Construction Bureau, Construction Technology Association, "Design Guidelines [Road Edition]" April 2000: 9-130 to 9-1
32

[0005]

When the construction site is inside the riverbed, except for the direct parts (caisson 100 and bridge post 160) that constitute the structure to be constructed, due to the regulations of the River Law, The temporary wall, which is a temporary structure, must be removed because it cannot remain below a predetermined depth, and the temporary wall must be easy to remove. On the other hand,
During excavation work, the temporary wall must be firmly supported for work safety. In the caisson 100 described in Non-Patent Document 1, when a steel sheet pile is used for the temporary wall 110, connection with the caisson 100 can be facilitated, and attachment / detachment of the steel sheet pile to / from the caisson involves some difficulty. However, since the steel sheet pile used is a U-shaped open section steel sheet pile, the rigidity is low, and if the temporary wall 110 becomes high, collapse due to insufficient rigidity of the temporary wall 110 itself and caisson. Since the binding force of the connection part of the steel sheet pile is much smaller than the binding force obtained when the steel sheet pile is driven into the support ground, during excavation work,
There is a problem that the steel sheet pile may come off from the connection portion.

[0006] Therefore, a steel sheet pile with an open cross section and a caisson 100.
If the connection part of is made to have a structure capable of obtaining a stronger binding force, the safety during excavation work is improved, but when removing the steel sheet pile, not only can it not be easily removed, In some cases, there is a problem that the steel sheet pile and the connecting portion cannot be completely removed. As a result, the composite open caisson in which the temporary wall 110 is made of steel sheet pile is not very suitable when it is necessary to work deep into the ground.

On the other hand, in the caisson 100, the temporary wall 11
When reinforced concrete is used for 0, the temporary wall 110 can be strengthened, but on the other hand, it is very time-consuming to remove the temporary wall 110 and it is difficult to completely remove it.
Effectively within the working range of the construction machine 2-3 m below the ground surface
The application limit is up to the degree, and it is not realistic to apply the open caisson deep into the ground. In addition, excavation work cannot be performed until the strength of the reinforced concrete of the temporary wall 110 is sufficiently developed, which is a major obstacle to shortening the construction process. As described above, since the temporary wall 110 of the caisson 100 resists earth pressure during construction of the caisson 100, the connection with the caisson 100 is required to be strong, whereas the temporary wall 110 is removed. By the way, caisson 10
It is very difficult to solve the problem of the temporary wall 110, because it is necessary to satisfy the contradictory condition for ensuring the safety of the worker, which is required to be easily removable from 0.

[0008]

As a result of various studies to solve the above-mentioned problems, the present inventor constructed a temporary wall of a caisson with a closed section steel sheet pile and a caisson with a closed section steel sheet pile. The present invention has been completed by adopting a structure that can be detachably attached and can obtain a strong restraining force. That is, a tubular blade portion, a tubular concrete skeleton portion continuously provided above the blade opening portion, and a plurality of sheet piles made of steel are connected to form a tubular shape. Provided above the concrete skeleton,
In a composite caisson structure having a removable steel material part, on the upper surface of the concrete skeleton part, at a predetermined interval , the lower side is embedded in the concrete skeleton part, and the upper part
A cylindrical socket part projecting from the upper end surface of the concrete skeleton part is provided, and a cylindrical main body part into which the socket part is fitted in the sheet pile and extending from both side walls of the main body part. And a closed section steel sheet pile having a connecting portion capable of connecting between adjacent sheet piles is used, and the tubular book of each closed section steel sheet pile is used.
Together with the socket portion to the body portion in the lower is fitted so as to be pulled out, the steel part is connected to each other adjacent ones are formed by the closed-section sheet piles are the connecting portions, the concrete
A sheet with which the closed cross section steel sheet pile abuts on the upper surface of the frame body.
And a concrete member provided with
Anchor extending from the upper end surface of the section and the extension of the anchor
A rod portion provided with a coupler connectable to the tip, and the rod
Pressed on the upper part of the part so that it can contact the upper surface of the steel part
Connected to the plate and the rod part, and the front via the pressing plate.
A pressing bolt for pressing the steel material part against the concrete skeleton part.
And a pressing means having a
The composite caisson structure is characterized in that it is pressed against the concrete skeleton . This allows the steel material part to be
Since it can be pressed against the cleat body,
When the steel part is pulled out when the body part is sunk
The steel part is not affected by earth pressure during excavation work.
And strongly resist. Furthermore, when removing the steel part
In addition, since the pressing force can be released,
Safer because it can be removed more easily
Build it is a composite type caisson and the child as possible.

Further, the socket portion is provided with the concrete cleaner.
To be attached in advance to the iron plate placed on the upper surface of the
Preferably. This allows the concrete frame
If the positional accuracy of the closed section steel sheet pile connected to the body is improved,
Both shall be erected vertically on the upper surface of the concrete structure.
This makes it easier to pull out steel sheet piles with closed cross sections.
Can be made easier.

Further, it is preferable that the rod portion is inserted into a hollow portion of the steel sheet pile with a closed cross section. According to this, since it is possible to prevent the pressing portion of the steel material portion from being accidentally damaged during excavation work of the caisson and the steel material portion becoming unstable, it is possible to reliably perform safe work. .

Another aspect of the present invention is the step of installing a tubular blade mouth portion at a construction site, forming a tubular concrete skeleton portion above the blade mouth portion, and digging inside the blade mouth portion. Concrete skeleton part forming step of sinking the blade mouth part and the concrete skeleton part, and burying the lower part in the concrete skeleton part at a predetermined interval on the upper surface of the concrete skeleton part
And the upper side projects from the upper end surface of the concrete skeleton
The step of forming a cylindrical socket portion, and the concrete
A step of disposing an anchor extending from the upper end surface of the body part;
Using a closed cross section steel sheet pile having a tubular main body section into which the socket section fits and extending from both side walls of the main body section and having a connecting section capable of connecting adjacent sheet piles , A cylinder that is fitted into the lower portion of the tubular main body , and has adjacent closed-section steel sheet piles connected to each other by the connecting portion, and a plurality of closed-section steel sheet piles that can be pulled out above the concrete skeleton. The step of forming a steel-shaped steel part and a coupler connectable to the tip of the extension part of the anchor.
The step of connecting the beam rod portion, and the rod portion,
A pressing plate that can contact the upper surface of the steel material is arranged
A pressure bolt is screwed onto the
The steel material part to the concrete skeleton part via a pressing plate
A method for constructing a composite caisson, which comprises the step of pressing . As a result, the steel part is
Since it can be pressed against the body, it sinks the concrete body
The steel part does not come off when
During the cutting work, the steel part is strongly resistant to the action of earth pressure.
To withstand. Furthermore, when removing the steel part, push
Since the pressure can be released easily,
It can be removed easily, making it safer to combine.
A type caisson can be constructed.

Furthermore, in the step of forming the socket portion, an iron plate is horizontally arranged on the upper surface of the concrete skeleton portion, and when the socket portion is fitted into the closed cross section steel sheet pile, the closed cross section steel sheet pile. However, it is preferable to dispose a seal member in advance at a position where it abuts on the iron plate. According to this, it is possible to prevent intrusion of water from the socket portion, and it is possible to vertically install the closed cross section steel sheet pile on the upper surface of the concrete skeleton. In addition, by installing the socket on the steel plate in advance, the accuracy of the installation position of the closed section steel sheet pile can be made accurate, and no unreasonable force acts on the joint between the steel sheet piles. The number of times of diversion can be increased, and the drawing operation can be easily performed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the composite caisson structure according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of the composite caisson according to the present embodiment. FIG. 2 is a plan view of the composite caisson according to the present embodiment. FIG. 3 is an enlarged explanatory diagram of the uppermost end of the concrete skeleton. FIG. 4 is a cross-sectional view of a closed section steel sheet pile used in the present embodiment. The composite caisson 10 according to the present embodiment includes a blade opening portion 12, a concrete skeleton portion 14 placed on the blade opening portion 12, a socket portion 16 and a socket arranged at the uppermost end of the concrete skeleton portion 14. Closed cross section steel sheet pile 18 which is erected at the uppermost end of the concrete frame portion 14 by the part 16 and is embedded in the uppermost end portion of the concrete frame portion 14 and passes through the hollow portion of the closed cross section steel sheet pile 18 to form a closed cross section. The outline is formed by the pressing means 20 arranged so as to protrude from the upper end portion of the steel sheet pile 18. The tubular member formed of the steel sheet pile 18 having the closed cross section is a steel material portion 21. The cross-sectional shape of the composite caisson 10 in the present embodiment is assumed to be a flat cylindrical shape (oval shape), but it goes without saying that it may be another shape such as a circular shape.

If necessary, a bracket 30 is provided on the inner peripheral surface of the steel material portion 21 and the steel material portion 21 is reinforced by a sill beam 32 or an uprising 34. It is more preferable because the portion 21 can prevent the portion from falling down.

The blade edge portion 12 is a flat annular ring assembled by welding steel plates. The blade mouth portion 12 is transported to the excavation site, installed at a predetermined position, and then concrete is poured from the opening portion. If a reinforcing bar (not shown) is erected on the upper end of the blade edge portion 12, stress transmission between the blade edge portion 12 and the concrete skeleton portion 14 can be ensured, which is convenient.

The concrete skeleton portion 14 is a blade edge portion 1.
It is a cylindrical body constructed on the upper surface of No. 2 and constitutes the side wall of the caisson. The concrete skeleton portion 14 in the present embodiment is assumed to be formed of cast-in-place concrete. After assembling a rebar and a form which are not shown in succession to the rebar erected on the upper end surface of the blade mouth part 12, concrete is poured into the form to form a concrete skeleton part 14. Since the concrete skeleton part 14 may be constructed in multiple steps,
It is preferable to arrange the reinforcing bars so as to wrap them with the reinforcing bars of the concrete skeleton portion 14 of the next layer, because the stress transmission between the concrete skeleton portions 14 of the upper and lower layers will be sure. After the poured concrete is hardened and a predetermined strength is developed, the ground in the portion surrounded by the blade opening 12 is excavated. Blade part 12 and concrete skeleton part 14
Due to its own weight, the blade edge part 12 and the concrete skeleton part 1
After sinking 4 and a predetermined depth, the concrete skeleton portion 14 of the next layer is added to the upper end of the concrete skeleton portion 14. By repeating the above work, the concrete skeleton portion 14 is constructed in the ground.

The socket portion 16 is disposed on the upper end surface of the uppermost step (hereinafter referred to as the final concrete skeleton 14f) of the concrete skeleton portion 14 and connects the concrete portion of the composite caisson 10 and the closed section steel sheet pile portion 18. It is for doing. Socket part 16 in the present embodiment
Is the final concrete skeleton part 14f as shown in FIG.
Embedded in the upper end surface of the main body 18a of the steel sheet pile 18 with a closed cross section
It is made up of a cylindrical body that is inserted into. Socket part 16
Are erected vertically at regular intervals on the upper end surface of the final concrete skeleton portion 14f.

A seal member 17 for stopping water is provided at a portion where the closed cross section steel sheet pile 18 contacts the upper end surface of the final concrete skeleton portion 14f. If the closed cross section steel sheet pile 18 is inserted into the socket section 16 by crushing the seal member 17, water can be suitably prevented from entering from the fitting section between the socket section 16 and the closed cross section steel sheet pile 18. By interposing a spacer 19 in the gap between the main body 18a of the closed cross section steel sheet pile 18 and the socket section 16, it is possible to prevent rattling between the socket section 16 and the closed cross section steel sheet pile 18. In addition, if the iron plate 50 is disposed on the upper end surface of the final concrete skeleton portion 14f and the socket portion 16 is previously attached to the iron plate 50 by welding or the like, the accuracy of the installation position of the closed cross section steel sheet pile 18 can be made accurate. In addition to the above, it can be erected vertically on the upper surface of the concrete skeleton portion 14. Further, since an unreasonable force does not act on the connecting portion between the closed cross section steel sheet piles 18, the work for pulling out the closed cross section steel sheet pile 18 is facilitated and the closed cross section steel sheet pile 18 can be diverted, which is preferable.

The pressing means 20 will be described with reference to FIG. The pressing means 20 presses the closed cross section steel sheet pile 18 against the socket section 16 so that the closed cross section steel sheet pile 18 (steel material section 21) inserted into the socket section 16 does not come off from the socket section 16. The pressing means 20 is the anchor rebar 2
A threaded portion is formed at the tip of the extension portion of 0a, and the anchor rebar 20
A tie rod 20c having a coupler 20b attached at one end to a screwing portion formed at the tip of the extending portion of a is connected to each other via the coupler 20b, and a steel pipe having a closed cross section is formed at the other end of the tie rod 20c. A pressing plate 20d that engages with the upper end of the sheet pile 18 is provided, and the tie rod 20 is inserted from above the pressing plate 20d.
It is configured by providing a tightening means 20e such as a bolt for tightening c.

The anchor rebar 20a is embedded in the space of the central portion of the socket portion 16 partly protruding from the upper end surface of the final concrete skeleton portion 14f so that the tip portion thereof extends. A threaded portion is formed at the tip of the anchor reinforcing bar 20a extending from the upper end surface of the final concrete skeleton portion 14f. A coupler 20b is attached to one end of the tie rod 20c so that the coupler 20b can be screwed into the screwed portion of the anchor rebar 20a. Therefore, the anchor rebar 20a and the tie rod 20c are connected to each other via the coupler 20b. The coupler 20b may be attached to the side of the anchor reinforcing bar 20a, or the anchor reinforcing bar 20a and the coupler 20c may be fixed in advance by welding or the like.

The tie rod 20c is a hollow portion of the main body portion 18a of the steel sheet pile 18 having a closed cross section inserted in the socket portion 16 (see FIG. 4).
(Refer to FIG. 3), and the length is set so as to project from the upper end portion of the steel sheet pile 18 having the closed cross section. A threaded portion is formed at the end of the tie rod 20c protruding from the closed section steel sheet pile 18, and a pressing plate 20d for pressing the closed section steel sheet pile 18 against the socket portion 16 is provided. Pressing plate 20d
Is inserted into the tie rod 20c and is formed to be larger than the outer end edge of the steel sheet pile 18 having the closed cross section. Pressing plate 20d
After contacting the upper end portion of the closed cross section steel sheet pile 18, by tightening the tightening means 20e such as a bolt, the closed cross section steel sheet pile 18 and the tie rod 20c are tensioned, so that the closed cross section steel sheet pile 18 becomes the socket section. It becomes possible to press 16 and connect. As a result, the closed section steel sheet pile 18 (that is, the steel material portion 21) is stabilized and the final concrete frame portion 1
Since it can be installed upright on 4f, it is possible to provide a safe working environment, which is preferable.

In the closed section steel sheet pile 18, for example, as shown in FIG. 4A, a main body portion 18a is formed in a quadrangular tubular shape, and joints 18b are provided from both ends of a pair of opposing side walls. . The joint 18b is formed in a substantially C shape in a plan view, and is formed so as to be connectable by allowing the opening portions 18c of the closed section steel sheet piles 18 to face each other in the longitudinal direction.

In the present embodiment, the concrete skeleton portion 14 is formed in a flat cylindrical shape (oval shape). Closed cross section steel sheet piles adjacent to the socket parts 16 standing at regular intervals along the plane cross section of the concrete skeleton part 14 are connected to each other by a joint 18b and then fitted into the socket parts 16 to form a continuous closed cross section. The steel sheet pile 18 (steel material portion 21) can be formed.
As described above, in order to form the steel material portion 21 that is a tubular body similar to the plane cross section of the concrete skeleton portion 14 by using a plurality of closed cross section steel sheet piles 18, a curved section is formed by the closed cross section steel sheet piles 18. Must. The closed cross section steel sheet piles 18 used for the curved portions are manufactured, for example, as shown in FIG.
That is, the closed section steel sheet pile 18 assigned to the curved portion
The outer joint 18bo is formed longer, and the inner joint 18bi is formed shorter than the outer joint 18bo. Further, for example, as shown in FIG. 4 (c), when connecting adjacent steel sheet piles 18 having closed cross sections,
It is convenient to use a sealing material (not shown) for the opening portion 18c because it is possible to prevent water from entering the connecting portion between the steel sheet piles 18 having the closed cross sections.

FIG. 5 is a flow chart showing an outline of work steps in the construction of the composite caisson according to the present embodiment. Hereinafter, a method for constructing the composite caisson according to the present invention will be described with reference to FIG. First, the blade edge portion 12 assembled by welding a steel plate is installed at the caisson construction target site (S101). When the installation of the blade edge portion 12 is completed, concrete is poured into the blade edge portion 12 (S102). Further, in order to ensure the stress transmission between the concrete skeleton portions 14 from the upper end surface of the blade edge portion 12, it is preferable to dispose them so that the reinforcing bars can be wrapped with each other.

When the concrete at the blade mouth portion 12 is hardened, the rebar extending from the blade mouth portion 12 is wrapped with the concrete rebar of the concrete skeleton portion 14, and a formwork is assembled to lay the concrete skeleton of the concrete skeleton portion 14. Prepare (S103). The operator confirms from the design drawing whether the concrete skeleton part 14 currently preparing for concrete placement is the final concrete skeleton part 14f, and if the current concrete skeleton part 14 is not the final concrete skeleton part 14f, the upper end After arranging the reinforcing bars for wrapping from the section, after assembling the formwork, concrete is placed in the formwork (SC1). After the concrete of the concrete skeleton portion 14 is hardened, the blade edge portion 1
2 excavates the ground in the inner part and sinks the blade tip part 12 and the concrete skeleton part 14 to a predetermined depth (SC
2). Then, the concrete skeleton portion 14 is continuously formed by the same procedure until the final concrete skeleton portion 14f becomes the uppermost step portion, and excavation and subsidence work is continuously performed.

The concrete skeleton portion 14 which is currently preparing for placing concrete is the final concrete skeleton portion 1.
If it is 4f, the final concrete skeleton part 14f
An anchor rebar 20a having a threaded portion formed at the tip is disposed at the upper end of the so as to extend from the upper end surface of the final concrete skeleton portion 14f (S104). In addition, the socket portion 16 is inserted into the hollow portion of the socket portion 16 so that the anchor rebar 20a fits into the final concrete skeleton portion 1.
The upper end surface of 4f is erected at regular intervals (S105). The socket portion 16 is firmly fixed so as to stand vertically on the upper end surface of the final concrete skeleton portion 14f.
In addition, the socket portion 16 is attached to the iron plate 50 in advance , the socket portion 16 and the iron plate 50 are disposed on the upper end surface of the final concrete skeleton portion 14f, and the seal member 17 as a water blocking material is disposed. If this is done, the position where the socket portion 16 is arranged can be made precise, and when the closed section steel sheet pile 18 is erected on the socket portion 16, the connection portion between the final concrete skeleton portion 14f and the closed section steel sheet pile 18 is provided. Can prevent the intrusion of water from the inside, and further has a closed cross section steel sheet pile 1
This is preferable because the pulling out work of No. 8 can be easily performed and the closed section steel sheet pile 18 can be diverted easily. After the upper end surface of the final concrete skeleton portion 14f is prepared in this manner, concrete placing of the final concrete skeleton portion 14f is performed (S106). When pouring concrete, the anchor rebar 20a disposed on the upper end surface, the socket portion 16, and the socket portion 16 and the iron plate 50 are carefully displaced while being prevented from being displaced.

After the final concrete skeleton portion 14f is hardened, a steel sheet pile 18 having a closed cross section is inserted into the socket portion 16,
It is erected on the upper end of the skeleton concrete (S107). Insert the closed section steel sheet pile 18 into each socket 16,
The joints 18b of the adjacent closed cross section steel sheet piles 18 are connected to each other, and the closed cross section steel sheet pile 18 forms a tubular body which is the steel material portion 21. Closed-section steel sheet pile 1 for all socket parts 16
When the standing of No. 8 is completed, the tie rod 20c to which the coupler 20b is attached is inserted into the hollow portion of each closed section steel sheet pile 18, and the tip end portion is screwed and attached to the screwed portion of the anchor rebar 20a (S108).

The tie rod 20c has a length protruding from the upper end of the closed section steel sheet pile 18, and a threaded portion is formed on the end side protruding from the closed section steel sheet pile 18. The tie rod 20c is formed to be larger than the outer shape of the closed section steel sheet pile 18, and the pressing plate 20d having the insertion hole 20ds in the central portion is inserted into the tie rod 20c and brought into contact with the upper end portion of the closed section steel sheet pile 18 and then pressed. By tightening from the upper side of the plate 20d with tightening means 20e such as bolts,
The pressing section 20d presses the closed section steel sheet pile 18 against the socket 16 (S109).

After all the closed section steel sheet piles 18 and the tie rods 20c are pressed by the pressing plate 20d and the tightening means 20e, the bracket 3 is attached to the inner peripheral surface of the steel material portion 21.
By attaching reinforcing members such as 0, the truss 32, and the uprising 34 (S110), the steel material portion 21 is prevented from collapsing due to earth pressure. Such a reinforcing member is a steel member 2
It is preferable to dispose at a plurality of locations depending on the magnitude of earth pressure acting on 1. In addition, the ground conditions of the construction site and the steel part 2
Depending on the shape of No. 1, there is a case where it is not necessary to dispose a reinforcing member such as the bracket 30, the truss 32, and the uprising 34, and it is also conceivable that no reinforcing member is used.

Since the side wall of the excavation hole is protected by the closed section steel sheet pile 18 (steel material portion 21) in the composite caisson 10 formed by the above steps, there is no risk of the excavation hole collapsing, and it is safe. It becomes possible to provide a working environment. In addition, since the seal member is disposed as a water blocking material between the final concrete skeleton portion 14f and the closed cross section steel sheet pile 18, or in the opening 18c of the joint 18b for connecting the closed cross section steel sheet piles 18, the sealing member is closed. It is also possible to prevent the infiltration of groundwater from the connecting portion between the steel sheet piles 18 in cross section. As described above, in the suitable working environment, the inner portion of the blade opening 12 is excavated, and the sinking work of the composite caisson 10 is continuously performed (S111), and the composite caisson 10 reaches the design position such as the support ground. The work of excavation, subsidence, and concrete placement of the concrete skeleton portion 14 is repeated. Since the closed cross section steel sheet pile 18 (steel material portion 21) has high rigidity, in the work of sinking the composite caisson 10, when the friction of the outer periphery of the caisson is large and the sink load is insufficient, an additional load such as water is applied. The subsidence can be promoted by acting on the top of the composite caisson 10.

After the composite caisson 10 reaches a predetermined position (supporting ground), the bottom plate concrete 60 is placed on the upper surface of the cutting edge portion 12 (S112). After the bottom plate concrete is hardened, earth and sand or the like is backfilled in the internal space of the concrete skeleton portion 14 (S113). Thereafter, the top plate concrete 62 is cast on the upper end surface of the final concrete skeleton portion 14f (S114), and after the top plate concrete 62 is hardened, the structure 70 such as a bridge pillar is constructed on the top plate concrete 62 (S115). When the construction of the lowermost layer portion of the structure 70 is completed, the reinforcing members such as the bracket 30, the girder 32, and the uprising 34 arranged at the lowermost stage are removed (S11).
6) Then, backfilling is performed (S117). The construction of the structure 70 (S115), the removal of the reinforcing member (S116), and the backfilling (S117) are divided into a plurality of operations. If the backfill surface has not reached the specified position, the structure 7
The construction work of 0 (S115), the removal work of the reinforcing member (S116), and the backfill work (S117) are repeated a predetermined number of times to perform backfill to a predetermined position. When the backfill surface reaches a predetermined position, the tightening means 20e such as a bolt for tensioning the tie rod 20c and the closed cross section steel sheet pile 18 and the pressing plate 20d are loosened to close the closed cross section steel sheet pile 18.
The pressing of the (steel material portion 21) to the socket portion 16 is released (S118). Closed-section steel sheet pile 18 with pressing force released
Is pulled out by a pulling machine (S119), and the construction work of the composite caisson 10 is completed (S120).

Although the composite caisson in the present embodiment has been described above, the present invention is not limited to this embodiment, and the present invention can be made even if various modifications are made without changing the gist of the invention. It goes without saying that it belongs to the technical scope of the invention. For example, in this embodiment, the concrete of the concrete skeleton portion 14 is formed by in-situ casting, but a concrete product manufactured at a factory may be assembled. In this embodiment, it is necessary to dispose a seal member at the joint of the concrete product produced at the factory and perform a treatment to prevent water from entering from the joint. Further, it goes without saying that the steel material portion 21 can be adopted on the upper end surface of the pneumatic caisson.

[0033]

The following effects can be obtained by adopting the present invention. Specifically, in a composite caisson with a concrete caisson and a steel material part, the steel sheet pile used is a steel sheet pile with a closed cross section and is detachably connected to the concrete caisson so that the steel material portion (temporary wall ) Can be firmly joined, and the steel material portion (temporary wall) can be safely and easily and reliably removed when removing the steel material portion (temporary wall).

Further, the socket is on the concrete skeleton part.
Pre-attached to the iron plate placed on the surface
The position of the steel sheet pile with a closed cross section to be connected to the concrete frame.
The placement accuracy is improved and the
Since it is possible to set it upright directly,
The pulling out work can be further facilitated.

Further, since the rod is inserted into the hollow portion of the steel sheet pile with a closed cross section, the pressing portion of the steel material portion is prevented from being accidentally damaged during excavation work, and the steel material portion is prevented from becoming unstable. Therefore, safe work can be surely performed.

Further, in the construction of the composite caisson, a step of installing a tubular blade mouth portion at a construction site, and forming a tubular concrete skeleton portion above the blade mouth portion, and excavating the inside of the blade mouth portion. The concrete skeleton part forming step of further advancing the blade mouth part and the concrete skeleton part, and at the upper surface of the concrete skeleton part with a required interval , the lower side is the concrete
It is embedded in the REIT skeleton and the upper side is the concrete skeleton
A step of forming a cylindrical socket portion standing on the upper surface ,
A process of arranging anchors from the top surface of the concrete skeleton
And a closed cross-section steel sheet pile having a tubular main body portion into which the socket portion is fitted and extending from both side walls of the main body portion and having a connecting portion capable of connecting between adjacent sheet piles. The socket portion is inserted into the lower portion of the tubular main body portion of the steel sheet pile, and adjacent closed cross section steel sheet piles are connected by the connecting portion, and the plurality of closed cross section steel sheet piles are pulled out above the concrete skeleton. And a cap that can be connected to the tip of the extension part of the anchor.
And a step of connecting the rod portion provided with
A pressure plate that can contact the upper surface of the steel material
A pressure bolt is screwed onto the rod part,
The steel material through the pressing plate to the concrete
By including the step of pressing on the body part, the steel material part (temporary wall) can be firmly joined during excavation work, and when removing the steel material part (temporary wall), the steel material can be safely and easily and reliably Part can be removed.

Further, in the step of forming the socket portion, a plate material is provided on the upper surface of the concrete skeleton portion, and the socket portion is previously attached to the plate material .
Accordingly, it is possible to accurately accuracy of the installation position of the closed section sheet piles, with a closed section sheet piles can be erected vertically to the top surface of the concrete skeleton, also prevent ingress of water from the socket part it can. Also, because unreasonable force does not act on the joint between steel sheet piles, pulling out steel sheet piles with closed cross sections
It has a remarkable effect such as easy work.

[Brief description of drawings]

FIG. 1 is a front view of a composite caisson according to the present embodiment.

FIG. 2 is a plan view of the composite caisson according to the present embodiment.

FIG. 3 is an enlarged explanatory view of the uppermost end of the concrete skeleton.

FIG. 4 is a cross-sectional view of a closed section steel sheet pile used in the present embodiment.

FIG. 5 is a flowchart showing an outline of a work process in the present embodiment.

FIG. 6 is an explanatory diagram showing an example of a conventional technique.

[Explanation of symbols]

10 composite caisson 12 Blade part 14 Concrete frame 16 Socket 18 Closed-section steel sheet pile 20 Pressing means 20a anchor rebar 20b coupler 20c tie rod 20d pressing plate 50 iron plate

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) E02D 23/06 E02D 5/16 E02D 23/08

Claims (5)

(57) [Claims] 1. A cylinder comprising a tubular blade mouth portion, a tubular concrete skeleton portion continuously provided to the blade mouth portion and provided above the blade mouth portion, and a plurality of sheet piles made of steel. Formed in a shape, provided above the concrete skeleton portion, in the composite caisson structure having a removable steel material portion, on the upper surface of the concrete skeleton portion, at a predetermined interval ,
The lower side is embedded in the concrete body part, and the upper side is
A cylindrical socket portion protruding from the upper end surface of the concrete skeleton portion is provided, and in the sheet pile, a cylindrical main body portion into which the socket portion is fitted,
A closed cross section steel sheet pile having a connecting portion extending from both side walls of the main body section and having a connection section capable of connecting adjacent sheet piles is used , and the socket is provided in the lower portion of the tubular main body section of each closed cross section steel sheet pile. While the parts are removably fitted, the closed cross section steel sheet piles are connected to each other by the connection section so that the steel material sections are formed, and the closed cross section steel sheet pile is formed on the upper surface of the concrete skeleton section.
An anchor that is provided with a sealing member that abuts and that extends from the upper end surface of the concrete skeleton part
And a coupler that is connectable to the tip of the extension of the anchor.
It is placed on the head part and the upper part of the rod part , and can contact the upper surface of the steel part.
Functioning pressure plate and the steel material connected to the rod portion through the pressure plate.
Part and a pressing bolt that presses against the concrete body part
The pressing means having the closed cross section steel sheet pile
Composite caisson structure characterized by being pressed against the rib body . 2. The socket portion is the concrete frame.
Pre-installed on the iron plate placed on the top of the body
The composite caisson structure according to claim 1, characterized in that
Structure. 3. The composite caisson structure according to claim 1, wherein the rod portion is inserted into a hollow portion of the steel sheet pile with a closed cross section. 4. A step of installing a tubular blade mouth portion at a construction site, and a tubular concrete skeleton portion is formed above the blade mouth portion, and the inside of the blade mouth portion is dug to advance the blade mouth portion and the concrete. A concrete skeleton part forming step of sinking the skeleton part, and a lower part at a predetermined interval on the upper surface of the concrete skeleton part.
Side is embedded in the concrete skeleton, and the upper side is
A step of forming a cylindrical socket portion projecting from the upper end surface of the cleat body portion ; and an anchor extending from the concrete body portion upper end surface.
The step of disposing, the socket portion is fitted, using a tubular cross-section steel sheet pile extending from both side walls of the main body portion and the main body portion, having a connecting portion capable of connecting between adjacent sheet piles, The socket portion is fitted into the lower portion of the tubular main body portion of each closed cross section steel sheet pile, and adjacent closed cross section steel sheet piles are connected by the connecting portion, and the plurality of closed cross section steel sheet piles allow the concrete skeleton to move upward. forming a steel material portion of the pulled out possible cylindrically, provided coupler that can be connected to the extending tip of the anchor
A step of connecting the rod portion, and a pressing plate capable of contacting the upper surface of the steel material portion with the rod portion
Is installed, and a pressing bolt is screwed onto the rod part to
With the pressure bolt, the steel material portion is
A method of constructing a composite caisson, comprising the step of pressing against a concrete skeleton . 5. In the step of forming the socket portion, an iron plate is horizontally disposed on the upper surface of the concrete skeleton portion, and when the socket portion is fitted into the closed section steel sheet pile, the closed section steel sheet pile is 5. The method for constructing a composite caisson as set forth in claim 4, wherein a seal member is arranged in advance at a position where it abuts on the iron plate.