JPH0363604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When building caisson-type structures on the ocean, in ports, etc., the present invention enables caisson installation work, which greatly affects the construction period, to be carried out without being affected much by sea conditions. This is related to the installation method of caisson.

Caisson installation, which is carried out in marine construction work to construct breakwaters, quays, seawalls, mooring facilities, etc. using the caisson construction method, has been carried out in accordance with the conventional installation method as follows. In other words, foundation rubble is poured into and around the planned installation location of the caisson and leveled to form the installation foundation for the caisson, the caisson is placed at a predetermined position on this installation foundation, and then the caisson is placed at a predetermined position on the installation foundation, and then the foundation rubble is placed in the area where the caisson is to be installed. Packing sand is poured into each compartment of the caisson, and after placing cover concrete on top of the loaded sand for filling (hereinafter sometimes referred to as filling sand), upper concrete is placed on top of it. That's what I was doing.

In order to implement such a conventional caisson installation method, the following sea conditions are required depending on the required number of days. The caisson installation work consists of the first step of putting in foundation rubble and leveling work by divers, the second step of placing the caisson on the installation foundation, adding filler sand, and covering with concrete. The process is divided into the third stage, which involves placing the concrete, and the fourth stage, which involves pouring concrete on top. After the completion of the second stage process, the caisson that has just been placed is likely to be moved from its predetermined position by waves, and in some cases, the side walls and bulkheads of the caisson may be destroyed. To prevent accidents,
Immediately after the step process is completed, the third step process is carried out,
The caissons must be anchored in place. In order to complete the caisson installation, the second stage of placing the caisson on the installation foundation requires 1 to 1.5 days, and the third stage of filling the caisson with filling sand and placing the cap concrete. 1 in the process of placing
~1.5 days are required. Therefore, it takes a total of 2 to 3 days to place the caisson on the installation foundation, fill it with sand, and place the lid concrete. Therefore, the above total number of days required for caisson installation is 2.
~3 days must be consecutive days of calm.
However, in general, in sea areas, particularly deep sea areas with severe sea conditions, the incidence of continuous calm sea conditions for two to three days is extremely low. Therefore, according to the conventional caisson installation method, the caisson installation work cannot be started until the day when it is predicted that there will be continuous calm for 2 to 3 days, resulting in a delay in the start of the installation work, and a delay in the installation work. Even after starting construction, the sea conditions suddenly changed and worsened during the construction work, making the installation work dangerous and causing construction to be interrupted, often resulting in accidents such as movement of the caisson, escape of filler sand, and destruction of the caisson wall. Once the caisson has been installed, it takes time to correct its position or redo the work, and this delays the completion of the caisson installation, which is the main cause of prolonging the overall construction period when installing the caisson using the conventional method. .

The inventors of the present invention have conducted intensive studies with the aim of providing a caisson installation method that does not have the above-mentioned drawbacks and can be carried out without being affected by short-lived or sudden changes in continuous calm sea conditions. discovered that the object could be achieved by interrupting the installation work by using a temporary cover for anchoring the caisson and preventing the filling sand from escaping, and thus developed the present invention.

In other words, the present invention involves placing sand for filling after placing the caisson on an installation foundation provided underwater.
When installing the caisson by placing the lid concrete and pouring the upper concrete, the caisson has a shape that is locked in a state that almost closes the filling sand inlet of the compartment of the caisson, and it has a shape that is locked in a state that almost blocks the filling sand inlet of the compartment of the caisson. Temporary lids for the number of compartments are prepared in advance and have the same weight as the number of compartments, and the caisson installation work is carried out by dividing the weight of the caisson without filling sand into a predetermined position on the installation foundation in response to the wave force. Depending on the changing sea conditions during the construction, the temporary lid is temporarily inserted to almost block the filling sand inlet of each compartment of the caisson while the filling sand is not yet being poured into the caisson placed on the installation foundation. The installation work was stopped by locking the caisson in the fixed state, and after waiting for the sea conditions to recover, the installation work was restarted, and the temporary cover was removed, filling sand was put in, and the cover concrete was placed. This article relates to a method for installing caissons during deterioration of sea conditions, which is characterized by the fact that

Hereinafter, the construction method of the present invention will be explained in detail with reference to the drawings. Fig. 1 is a vertical cross-sectional explanatory diagram showing a state in which the temporary lid is locked without filling sand in one embodiment of the method of the present invention, and Fig. 2 is an explanatory longitudinal cross-sectional view showing a state in which the temporary lid is locked without filling sand in one embodiment of the method of the present invention. Vertical cross-sectional explanatory view showing a state in which the temporary lid is locked in a state where filling sand has not been completely inserted, No. 3
Figures 4 and 5 are a perspective view, a top view, a front view, and a front view, respectively, showing one example of a temporary lid body, and Figures 6 and 7.
The figure and FIG. 8 are a perspective view, a plan view, and a front view, respectively, showing another example of the temporary lid.

In carrying out the construction method of the present invention, the foundation rubble is transported by a stone carrier or a gas boat and thrown into the planned installation position of the caisson or around it, and the caisson is installed as shown in Figures 1 and 2. Setting it as foundation 1 is the same as in the conventional construction method. Once the installation foundation 1 has been constructed, the caisson 2 is then placed in its predetermined position according to a conventional method, but in the construction method of the present invention, prior to this, temporary lid bodies 3 are prepared in the number of compartments 2a of the caisson 2. I'll keep it that way. The temporary lid body 3 used in the construction method of the present invention has the following shape and weight. Its shape is such that it is locked in a state that substantially closes the filling sand inlet of the compartment 2a of the caisson 2, as illustrated in FIG. In addition, its weight is large enough to withstand the wave force of large waves that can be expected during construction in the sea area where a structure is to be constructed using the caisson construction method. When the caisson 2 is locked in the filling sand inlet of each compartment 2a of the caisson 2 with no filling sand loaded, the caisson 2 is installed on the foundation 1.
This is the weight that each temporary lid body 3 shares in proportion to the number of total weights sufficient for fixing on the top. The temporary lid body 3 is made of concrete, reinforced concrete, iron, or the like.

Such temporary lids 3 as many as the number of compartments are prepared, and the caisson 2 is placed at a predetermined position on the installation foundation 1 using a tugboat, a crane boat, etc. while injecting seawater according to the conventional method as described above. If the sea conditions continue to be calm even after the caisson 2 has been placed, filler sand is immediately poured into each compartment 2a from the filler sand inlet into each compartment 2a using a Gatsuto boat or sand pump according to the usual method. If the sea conditions worsen before the filling sand has been placed and the filling sand has not yet been completed, the following measures can be taken using the construction method of the present invention. That is, a state in which the filling sand has not been completely added, for example, a state in which the filling sand has not been started and no filling sand has been added at all as shown in FIG. As shown in the figure, when the charging of sand for filling has started and the sand for filling 4 has been poured halfway into each compartment 2a, but the predetermined amount has not yet been reached, the sea conditions deteriorate. In this case, as shown in FIGS. 1 and 2, the temporary lid 3 is locked in a state that almost blocks the filling sand inlet of each compartment 2a, and the caisson 2 is closed.
The installation work is temporarily suspended after the system is set in place. Since this temporary lid body 3 has enough weight to keep the caisson 2 in a fixed state even when sand for filling the caisson 2 has not been put into the caisson 2 as shown in FIG. If the filler sand is added halfway, its fixation will be even better. In this way, the dead weight of the caisson 2 and the temporary lid body 3 are
The total weight of the caisson 2 and the additional weight of the filler sand 4, which may be added, anchors the caisson 2 on the installation foundation 1, even under adverse sea conditions.
Movement of the caisson 2 and wall destruction will not occur, and filling sand 4 will not escape from the filling sand input port which is almost blocked. In order to facilitate the work of locking the temporary lid body 3 to the caisson 2, the third
As shown in Figures to Figures 5, a hanging fitting 3a for hanging the crane is embedded in the upper surface of the temporary lid 3, and its head is exposed inside the concave box cutout 3b, and a sand inlet for filling is provided. Fluid vent hole 3 for making it easier for air or water to escape from each compartment 2a when it is almost closed
It is preferable to drill a hole c.

The installation work of the caisson 2 is temporarily suspended with the temporary lid body 3 locked to the caisson 2 as described above, and the installation work is restarted after waiting for the sea conditions to recover. After restarting the installation work, the temporary cover body 3 may be removed using a crane or the like, and filling sand may be introduced through the opened filling sand inlet.
As shown in FIG. 8, a filling sand input pipe 5 having a flange at the outer end is provided in the temporary lid 3 shown in FIGS. 3 to 5, and the temporary lid 3 is installed after restarting the installation work. It is also possible to use a construction method in which a sand transport pipe is connected to the sand input pipe 5 while the sand is locked, and a water-sand slurry is pumped using a sand pump or the like, and the sand for filling is poured into each compartment 2a. . In this case, in order to make it easier for the water to be forcibly discharged from the fluid drainage hole 3c as the water-sand slurry is pressurized into the compartment 2a, the fluid drainage hole 3c is shown in FIGS. 6 to 8. Hole 3c
It is preferable to keep the diameter of the diameter large. According to this method of restarting the installation work without removing the temporary cover body 3, it is convenient in the case where the sea conditions suddenly change again and the installation work is interrupted again before the sand filling for filling has been completed after the installation work has been restarted. Yes, and the temporary lid body 3 may be removed after the filling sand is completely inserted. In this way, when any of the above construction methods is adopted after the installation work of caisson 2 is resumed, the temporary cover body 3 must be removed and filling sand must be added before the cover concrete is placed, and then the cover concrete is filled. Placing it on top of the sand 4 and placing the upper concrete on top of it is the same as in the conventional construction method.

According to the construction method of the present invention, as long as the caisson 2 is placed at a predetermined position on the installation foundation 1, even if the sea conditions worsen before filling with sand is completed, the temporary cover 3 can be installed as described above. By locking it, the installation work can be temporarily interrupted safely. If the caisson 2 is placed for 1 to 1.5 days and the temporary lid body 3 is locked for 0.5 days, the total of 1.5 to 2 consecutive days is calm, then the temporary lid body is removed from the installation of the caisson 2. This can be done with 3 locks. Therefore, according to the construction method of the present invention, installation work for the caisson 2 can be started when it is predicted that calm sea conditions will continue for 1.5 to 2 consecutive days. The occurrence rate of such a number of days of calm sea conditions is much higher than the number of consecutive calm days of 2 to 3 days required in the case of conventional installation methods. In fact, according to the construction method of the present invention, if the work of locking the temporary lid body 3 is started immediately when a deterioration of the sea conditions is predicted or at an early stage when signs of deterioration are recognized, in most cases, the sea conditions will be in full swing. It is completed by the time the situation worsens. Therefore, after the caisson 2 is placed on the installation foundation 1, the installation work can be safely temporarily suspended even if the sea conditions worsen at any time, and the installation work can be restarted immediately after the sea conditions recover.

According to the construction method of the present invention, as explained above, the caisson installation work can be started on a day when the sea conditions with a relatively high occurrence rate are expected to be calm for 1.5 to 2 consecutive days, and the construction work can be started during the installation work. Even if the sea conditions deteriorate, the construction period will only be extended by the minimum number of days during which the sea conditions worsen. In this way, the construction method of the present invention is valuable because it enables the installation of caissons to be carried out without much influence from sea conditions, hastens the completion time, and thereby prevents delays in the overall construction period of the structure. It is.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional explanatory diagram showing a state in which the temporary lid is locked without filling sand in one embodiment of the method of the present invention, and Fig. 2 is an explanatory longitudinal cross-sectional view showing a state in which the temporary lid is locked without filling sand in one embodiment of the method of the present invention. Fig. 3 is an explanatory longitudinal cross-sectional view showing a state in which the temporary lid is locked in a state in which filling sand has not been completely inserted;
Figures 4 and 5 are perspective views, plan views, and front views of one example of a temporary lid, and Figures 6, 7, and 8 are views of another example of a temporary lid. They are a perspective view, a plan view, and a front view. 1... Installation foundation, 2... Caisson, 2a... Compartment room,
3...temporary lid body, 3a...hanging metal fittings, 3b...box cutter, 3
c...Fluid vent hole, 4...filling sand, 5...filling sand input pipe.

Claims (1)

[Scope of Claims] 1. When installing the caisson by placing filler sand, placing cover concrete, and pouring the upper concrete after placing the caisson on the installation foundation provided in the water, The caisson has a shape that is locked in a state that almost closes the filling sand inlet of the compartment, and the caisson without filling sand is placed on the installation foundation against the wave force that can be expected during construction. Temporary lids are prepared in advance for the number of compartments, which share the weight of fixing the caisson in a predetermined position. While the filling sand has not been completely inserted, the temporary lid is locked to almost block the filling sand inlet in each compartment of the caisson, the caisson is fixed, and the installation work is interrupted. This method of installing a caisson during deterioration of sea conditions is characterized by restarting the installation work after waiting for the recovery of the water, removing the temporary cover body, and inserting filling sand before placing the cover concrete. 2. The method for installing a caisson during deterioration in sea conditions as set forth in claim 1, in which filling sand is introduced after the temporary lid is removed after restarting the caisson installation work. 3 Installation of a caisson during deterioration of sea conditions as set forth in claim 1, in which the temporary lid is removed after the caisson installation work is resumed and filler sand is put in with the temporary lid locked. Construction method.