JPH0381422A - Caisson method - Google Patents

Abstract

PURPOSE:To simplify construction operations by laying up hollow concrete ring bodies constructed by a combination of concrete segments vertically in sequence to form a caisson body according as excavation of the inside of the ring bodies is progressed. CONSTITUTION:Concrete segments 1 are connected to each other by bolt- junctions to form hollow concrete bodies 21-2n respectively. A cutting edge 3 is then mounted to the lower part of the lowermost ring body 21. After the ring bodies 22,... are piled up on the ring body 21 by one lift, the inside of the ring bodies 21... is excavated by an excavator to sink and settle the ring bodies. A new ring body is then piled up on the upper-most ring body to sink the ring bodies. After piling-up and sinking of the ring bodies are repeated in the same manner and a caisson body 5 is sunk and settled at a specified depth, concrete is placed on the bottom ground inside the caisson body 5.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a caisson (well) construction method.

[Conventional technology]

The construction method of sinking caissons is often used to construct the foundations of bridge piers, abutments, and other structures, but conventionally it has been common to construct the caisson frame by pouring concrete on-site.

[Problem to be solved by the invention]

The conventional method of constructing a caisson frame on-site makes on-site work complicated and takes a long time.

To solve this problem, it is possible to precast the frame and reduce the on-site work to just connecting and sinking, but this is difficult to apply to caissons with medium to large cross sections due to the transportation of parts.

The purpose of the present invention is to eliminate the inconveniences of the conventional example, to allow even large caissons to be assembled freely using transportable members, to simplify the work and shorten the construction period, and as a result, to reduce costs. Our goal is to provide a caisson construction method that can.

[Means to solve the problem]

In order to achieve the above object, the present invention involves forming a caisson frame by sequentially stacking and connecting hollow concrete rings made of segment combinations in the vertical direction as internal excavation progresses, and hollow concrete rings made of segment combinations. The wheels are stacked vertically in order to form a caisson frame, and a traction member with a ground anchor at the lower end is attached to these wheels, and a reaction force receiver is placed on the topmost concrete wheel. The gist of this reaction force receiver is to provide a traction jack on the material, which is connected to the upper end of the traction member, and to use the traction jack to dig the caisson frame.

[Effect]

According to the present invention as set forth in claim 1, the size of one segment is suitable for land transportation such as a trailer, and at the site, such a segment can be used to form a hollow concrete ring of the required diameter. Furthermore, after 1971 minutes of this wheel body is sequentially stacked and connected in the vertical direction, internal excavation is performed and it is deposited.

After the concrete has been deposited, hollow concrete rings made of segments are stacked and added to the concrete, and the concrete is then deposited.

According to the present invention as set forth in claim 2, in which the caisson is characterized by repeating such steps to a predetermined depth, in addition to the above-mentioned action, the sinking is performed not only by the weight of the skeleton and the sinking load, but also by the propulsive force of the traction jack. Since press-fitting can also be used, the installation work can be done quickly.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the caisson construction method of the present invention, in which 1 is a concrete segment and 2° to 2 is a circular hollow concrete ring formed by combining the concrete segments 1.

The concrete segments 1 are connected by bolts in the same way as the concrete segments used in the tunnel shield construction method, and the rings 21 to 2. , respectively.

As shown in Figure 3, the hollow concrete wheel 2 at the lowest stage
．． Attach the cutting edge 3 with a triangular cross-section using a wheel with the same diameter under the
Further, the hollow concrete ring body 2 at the lowest stage. wheel 2 on top of
□ Stack... The upper and lower stages of the wheel body are connected to each other by joint bolts as in the connection between the segments 1, but they may also be connected by PCI material.

In this way, the height that can be raised from the ground by stacking is 5.
It is possible up to about m.

The inside of the stacked hollow concrete rings is excavated with an excavator 4, and the concrete is sunk as in the conventional caisson construction method.

For this excavation@4, a clam shell, a drilling bucket, or a reverse type underwater excavator is used.

Once one lift has been sunk, a new concrete wheel consisting of concrete segments 1 is further stacked on top of the topmost concrete wheel by the amount of the above-mentioned sinking length, and then the new concrete wheel is placed again. The entire body is submerged so that its body is underground.

In this way, stacking and sinking of the wheels is repeated, and once the caisson frame 5 has sunk to a predetermined depth, the bottom concrete is poured into the frame.

In the second embodiment, the hollow concrete rings 21 to 27 formed by the concrete segment 1 are arranged in the lowermost hollow concrete ring 2 as shown in FIGS. 1 and 2. wheel 2 on top of
When stacking □..., attach a traction member 9 made of PClil material or the like whose lower end is connected to an earth anchor 8 set below the cutting edge 3 to the outside of the hollow concrete wheel 21 to 2 degrees, A beam-like reaction force receiving material 12 was placed on the uppermost concrete wheel, and the upper end of the traction member 9 was connected to a traction jack 10 provided thereon. This traction jack 10 is a center hole type jack and the fixing member 11
It is removably connected to the traction member 9.

When excavating the stacked hollow concrete ring bodies with the excavator 4, the traction jack IO is extended to press-fit the caisson frame 5.

If 1,971 minutes were sunk, these reaction force receivers would be made of material 12.
After removing the towing jack 10, a new concrete wheel consisting of the concrete segments 1 is further stacked on top of the uppermost concrete wheel by the length of the above-mentioned sinking length, and the traction member 9 is inserted again. For the reaction force receiver, the material 12 and the traction jack 10 are set, and the whole is press-fitted so that the new wheel body is inserted into the ground.

In this way, the stacking and press-fitting of the rings are repeated, and once the caisson frame 5 has sunk to a predetermined depth, the bottom concrete is poured into the frame.

FIG. 4 shows a third embodiment of the present invention, in which the hollow concrete rings 2I to 27 formed by combining the concrete segments 1 are rectangular, partition walls 6 are provided as necessary, and the caisson frame 5 is made of concrete. It was decided that it would be obtained as a box. Note that this partition wall 6 may be removed after the caisson frame 5 is lowered to a predetermined depth.

The method of sinking and other details are the same as those of the first and second embodiments, so the explanation will be omitted.

Also, although not shown in the drawings, a hollow concrete wheel 2. ~
27 can also be formed into other rectangular shapes such as pentagonal or hexagonal.

(Effects of the Invention) As described above, the caisson construction method of the present invention is assembled using transportable segments, and is suitable for use in bridge piers, abutments, and other foundation structures as deep structures of 30 to 50 m class. Even caissons with large cross-sections can be assembled freely, and compared to the conventional case where the caisson frame is formed using cast-in-place concrete, it simplifies the work and shortens the construction period, resulting in significant cost reductions. It is something that can be done.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the caisson construction method of the present invention;
FIG. 2 is a side view of the essential parts of the same, FIG. 3 is a longitudinal sectional side view of the tip end portion of the same, and FIG. 4 is a perspective view showing another embodiment. 1... Concrete segments 21 to 2I,... Hollow concrete ring body 3... Cutting edge 4... Excavator 5... Caisson frame 6... Bulkhead 8... Earth anchor 9... Traction member 10... Traction jack 11... Fixing member 12... Reaction force receiver is material No. 1 Fig. 3 Fig. 4

Claims (2)

[Claims] (1) A caisson construction method characterized by forming a caisson frame by sequentially stacking and connecting hollow concrete rings formed by combining segments in the vertical direction as internal excavation progresses. (2) Hollow concrete rings formed by combining segments are sequentially stacked vertically to form a caisson frame, and a traction member with an earth anchor at the lower end is attached to these rings, and the top concrete ring A caisson construction method characterized in that a reaction force receiving material is placed on the reaction force receiving material, a traction jack connected to the upper end of the traction member is provided on the reaction force receiving material, and the caisson frame is excavated with the traction jack.