JPS6040428A - Installation work of caisson - Google Patents

Abstract

PURPOSE:To prevent the imbalanced settlement of a caisson by a method in which piles are loosely thrust through guide holes provided in the side walls and partition walls of a caisson, and the tips of the piles are driven into the ground. CONSTITUTION:A caisson 1 consisting of side walls 1a', plural partition walls 1a'', and plural pile guide holes 1b is set on a flat ground 3 under water. When the ground 3 is not flat, gravels 4 are charged to correct the surface to flat surface, plural piles 2a are loosely thrust through the holes 1b, and the tips of the piles 2a are driven into the ground. The caisson 1 can settle vertically without inclination under guidance of the piles 2, although settled by scouring caused by tidal current and under its own weight, and therefore, the imballanced settlement of the caisson can be prevented. Sand 5 is packed into the caisson, a cover 6 is placed on it, and upper concrete cover 7 is placed.

Description

[Detailed Description of the Invention] The present invention makes it possible to carry out caisson installation work, which greatly affects the construction period, construction cost, etc., without being affected by sea conditions. This concerns the installation method of the cane.

Caisson installation carried out in marine construction work to construct breakwaters, quays, berths, mooring facilities, etc. using the caisson construction method is as follows:
The installation was carried out as follows according to the conventional installation method. In other words, stones transported by stone transport ships, Gatsuto ships, etc. are put in as foundation rubble, the foundation rubble is leveled by divers and used as the foundation for installing the caisson, the caisson is placed on the foundation rubble, and then the foundation rubble is leveled by divers. Sand, etc. transported by a Gatsuto ship, etc. is filled into the filling, and the lid concrete is re-placed on top of the filled sand, etc. (hereinafter referred to as filling sand), and the caisson enclosure is closed.
The foundation blocks and covering stones were placed on top of the foundation rubble exposed in the water, and finally the upper concrete was poured on top of the wax concrete that had already been placed. When implementing the conventional caisson installation method (FC), the work of accurately inserting the foundation rubble into the designed position and the work of leveling the foundation rubble by divers are susceptible to the effects of waves and currents, especially in severe sea conditions such as deep water. In these waters, the work of putting in the foundation rubble is inaccurate and the leveling work is even dangerous, and in addition, the water depth is about 20. In the above locations, the efficiency of leveling work will be greatly reduced. Furthermore, during the caisson installation, after the 1 to 1.5 day process of placing the caisson on the foundation rubble, filler sand is immediately poured and capping concrete is placed to prevent the caisson from shifting due to waves. 1 to 1.5 days, and these steps had to be carried out consecutively within a total of 2 to 6 days. However, the incidence of continuous calm sea conditions for 2 to 3 days to allow caissons to be installed is extremely low. Therefore, according to the conventional caisson installation method, it is not possible to start the caisson installation work on the day 1 when it is predicted that there will be continuous calm for 2 to 6 days. This lengthened the overall construction period and increased construction costs.

In addition, when using the above-mentioned conventional survey method for caissons, a large amount of high-quality foundation rubble is used, which not only increases the construction cost due to the bulk of the stone transport path.
There was also the risk of causing construction pollution such as dump pollution caused by land transport, and ocean pollution problems due to the large amount of water being dumped into the sea in June.

The present inventors solved the above-mentioned drawbacks of the conventional caisson construction method, and achieved a system that allows installation without being affected by sea conditions, uses only a small amount of foundation rubble, etc., and is easy to install on-site. Tsumezu, which has been carefully studied with the aim of providing construction methods,
The present invention was achieved by discovering that the object can be achieved by a construction method in which the caisson is free to move vertically but is prevented from moving horizontally by passing a pile through the caisson and driving its tip into the ground. did.

That is, in the present invention, a plurality of pile guide holes are vertically penetrated in advance in the hard wall of a caisson, the caisson is placed on flat ground underwater, and then a plurality of piles are inserted into the pile guide holes, respectively. The feature is that after a hole is loosely inserted through the hole and its tip is driven into the ground, filling sand is poured into the caisson, cover concrete is placed, and the upper part is poured after a certain period of time has elapsed. This is related to the installation method of caisson. 'below,
The construction method of the present invention will be explained in detail using the drawings.

Figure 1 is a plan view of one example of a caisson used in the construction method of the present invention; B in FIG. 2 shown,
-B line cross-sectional explanatory diagram.

In order to carry out the construction method of the present invention, first, a plurality of pile guide holes 1b are vertically penetrated and provided in advance in the solid wall of the caisson 1, that is, in the side wall 1a' or in the partition wall 1a/7. The position of the pile guide hole 1b does not need to be particularly limited, but as shown in FIG.
It is preferable to increase the wall thickness at each intersection of (the partition wall 1a/7 and the partition wall 1a) and provide the pile guide hole 1b.

In Fig. 2, the pile guide holes 1b are provided at all intersections, but it is not necessary to use all the intersections, and the pile guide holes 1b are provided as evenly as possible during the manufacturing of the caisson 1 or the driving of the piles 2. All you have to do is select intersections at multiple locations.

The caisson 1 prepared in this way is placed at a predetermined position on the ground 6 underwater. When placing the caisson 1, if the ground 6 is flat, use the ground 6 as it is as the foundation of the caisson. It is directly corrected and flattened to be used as the foundation for the caisson 1. If the ground is extremely uneven, stones 4 with small particle diameters such as sand, small gravel, and crushed stones are poured onto the ground 6 to make it flat. The land is corrected and flattened to be used as the foundation for the caisson 1. Since stones 4 with a small particle size smaller than small crushed stones are used, the leveling work is easy and does not interfere with driving piles, and the foundation The amount of stone used is significantly less than that of rubble.Once the caisson 1 is placed in the predetermined position on the ground 6 in this way, the caisson 6
As shown in the figure, several piles 2 are connected to each pile guide hole 1.
b is loosely fitted, that is, using a pile having a smaller diameter than the inner diameter of the pile guide hole 1b, the pile is passed through with a gap provided between the two, and its tip a is driven into the ground 6. In such a state, even if the caisson 1 is subjected to horizontal pressing force due to waves or currents, the caisson 1 is fixed in position on the horizontal plane by the plurality of piles 2, so it will not slide or fall at all. do not have. When the caisson 1 sinks due to its own weight and the scouring action of waves and currents, the plurality of piles 2 penetrating the pile guide holes 1b of the caisson 1 in a loose-fitting manner will cause the caisson 1 to sink. Caisson 1 does not tilt in the slightest and maintains the predominance of that 1 trench and is guided by pile 2 and sinks only in the vertical direction, so unequal settlement does not occur at all. Since the pile 2 functions to prevent the caisson 1 from sliding, overturning, and uneven settlement as described above, the rooting length of the tip portion 2a driven into the ground 6 is the length necessary for the above-mentioned functions. It's fine if it's
Does not require the same length as support piles. Also, the diameter of 2 il 2.

The length, cross-sectional performance, and number of canes are determined by the expected wave depth at the time of cane installation, design wave height, and caisson shape.

When the construction process of placing the caisson 1 and driving the pile 2 is completed in this way, the next step is filling with sand or the like 5.

Construction work such as placing the lid concrete 6 and pouring the upper concrete 7 will begin. However, in the method of the present invention, the caisson can be constructed even if the filling with sand, etc. 5 has not been completed by placing the pile 2 as described above. 1 is kept completely stable, so after a total of 1.5 to 2 days required for placing the caisson 1 and completing the pouring of the pile 2, the process of adding sand etc. 5 and placing the cover concrete 6 was started immediately. There is no need to start work, but due to sea conditions or other circumstances, after the process of placing caisson 1 and pouring pile 2 is completed, the work is temporarily suspended, and sand, etc. 50 and the process of placing the lid concrete 6. Therefore, according to the method of the present invention, caisson installation work can be started when it is predicted that calm sea conditions will continue for 1.5 to 2 consecutive days. And this level of calm sea conditions for several days is continuous with the calm required for conventional installation methods.
The appearance rate is much higher than ~6 days and 105 days,
The caisson installation period is not affected by sea conditions. Caisson 1 sinks as it is placed and sand, etc. 5 is thrown in, and then it gradually continues to sink due to the scouring action of waves and currents, but due to the effect of pile 2, these sinks are equal sinks, Once the land subsides by a certain amount, it will be balanced by the supporting capacity of the ground and the subsidence will eventually stop. In addition, after placing the lid concrete 6 on top of the filler sand 5, the upper concrete 7 may be poured in the same manner as in the conventional construction method, but the design height is increased by compensating for the settlement when placing the upper concrete door. It is preferable to raise the height of the upper concrete 7 so that it can be secured.

In order to prevent the ground 6 on which the caisson 1 is placed from being scoured, it is preferable to install foundation blocks 8 on the outside and inside of the port of the caisson, as shown in FIG.

As described above, according to the method of the present invention, when constructing a caisson-type port structure, stones with small grain size are used instead of foundation rubble for the foundation construction of the caisson, and the solid walls of the caisson are penetrated in a loose-fitting manner. By driving piles into the ground and fixing the horizontal position of the caisson to prevent the caisson from sliding, overturning, and uneven settling, it is possible to interrupt the construction work after the caisson is placed on the ground. Therefore, the caisson installation work can be started and completed without being significantly affected by sea conditions. Thus, the method of the present invention has the advantage of speeding up the construction period, reducing the amount of stone needed, lowering construction costs, and eliminating construction pollution.

[Brief explanation of the drawing]

Fig. 1 is a plan view and center vertical sectional view of an example of a caisson used in the construction method of the present invention, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, and Fig. 5
The figure is B-B in Figure 2 showing the implementation state of the method of the present invention.
It is a line cross-sectional explanatory drawing. 1...Caisson 1a...Solid wall 1a'...Side wall 1a...Partition wall 1b...Pile guide hole 2...Pile 2a...Tip 6...Soil 4...Small grain size stone 5...Sand, etc. 6. Lid concrete 7. Upper concrete 8. Negoma block, etc.

Claims (1)

[Claims] 1. A plurality of pile guide holes are provided vertically in advance in the hard wall of the caisson, and the caisson is placed on flat ground underwater, and then the plurality of piles are inserted into the solid wall of the caisson, respectively. After passing through the pile guide hole loosely and driving its tip into the ground, fill the caisson with filler sand after a certain period of time, place the contourite, and pour the top concrete. A distinctive caisson installation method. 2. The caisson construction work according to claim 1, which uses a caisson in which pile guide holes are provided at intersections of hard walls.