JPH0260809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a manhole installation method using the caisson construction method.

``Conventional technology'' In the conventional manhole construction method using the caisson construction method, a hard thin plate is protruded from the lower edge of the manhole body just above the cutting edge, so when excavating just below the cutting edge, the thin plate gets in the way and interferes with the excavation work. The work area inside the manhole body is reduced due to the thin plate, and the excavated earth and sand enters between the inner surface of the manhole body and the thin plate, causing the thin plate to descend and become embedded, resulting in the excavation directly below the opening of the manhole. became difficult. Finally, a foundation was constructed at a level directly below the cutting edge, a ready-made rebar cage was placed on top of it, and the tip of the thin plate mentioned above was laid on the bottom of the cage, and in this state, concrete was poured on top of the reinforcing bar cage. Since the bottom surface was formed by the thin plate, cracks were likely to occur along the thin plate, and the connection between the concrete bottom surface and the inner surface of the manhole body and the connection between the concrete bottom surface and the foundation at the connection point were not achieved, and the lower edge of the manhole body It was difficult to improve the strength of the connection between
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"Problems to be Solved by the Invention" The present invention aims to provide a caisson construction method for manhole bodies that has a strong bonding force between the manhole body, the concrete bottom surface, and the foundation, and that construction can be carried out safely and quickly. .

"Means and Procedures for Solving the Problems" The present invention involves lowering a manhole body, which has a cutting edge at its lower edge, into the ground by excavating and removing soil directly below the cutting edge, and After removing the earth and sand,
A foundation is constructed at the level of the cutting edge described above, the tip of the bolt is screwed into the female screw hole opened on the inner surface of the main body, and a ready-made concrete bottom plate is placed on the foundation, protruding from the outside surface of the bottom plate. It is constructed by a manhole installation method characterized by welding the reinforcing bars and the bolts, and then pouring concrete into the gap between the inner surface of the main body and the outer surface of the bottom plate.

``Operation'' Therefore, by excavating the earth and sand directly below the blade opening and inside the manhole body, the body is propelled downward into the ground by its own weight. Since there are no protruding objects inside the manhole body, the excavation work can be carried out without making the work area cramped, and the earth and sand directly under the cutting opening can be excavated and removed without any obstructions. After that, the constructed foundation comes into contact with the tapered surface of the cutting edge after descending to the specified position.
Stop the body from descending. The concrete bottom plate placed on the top of the foundation and the inner surface of the main body are integrated at the reinforcing stage by welding bolts and reinforcing bars, and the gap becomes the concrete bottom surface due to the poured concrete, and the concrete in the gap becomes reinforced concrete. At the same time, it will be connected to the foundation directly below using the same concrete.

Embodiment The upper and lower surfaces of the rectangular manhole main body 2 are open as shown in FIG. 4, and a cutting edge 1 is formed along the lower edge. Immediately above the blade mouth 1, an insert female screw 10 buried inside the main body 2 is opened to the inner surface. The embedded portion of the female screw 10 forms a bending anchor 11 or is integrally welded to the reinforcing bar of the main body 2. Then, when the main body 2 is supported on the ground 12 and the earth and sand immediately below the cutting edge 1 is manually excavated with an excavator and the earth is discharged to the center, the main body 2 is lowered by its own weight by the excavation depth. The above-mentioned removed earth and the internal earth and sand of the main body 2 are excavated manually or mechanically (power shovel, etc.), discharged into the ground 12, and buried from the state shown in Fig. 1A to the state shown in Fig. 1B. In this state, a foundation 3 is formed by laying chestnut stone in contact with the cutting edge 1 and hardening it with mortar. The top surface of this foundation 3 is the blade mouth 1
It is best to match the upper edge level of . Either of the excavation and removal work directly below the blade opening 1 and the excavation and removal of earth inside the manhole body may be performed first. In this state, the tip of the short bolt 5 is screwed through the opening of the screw hole 4 of the female screw 10, and the other end of the bolt 5 protrudes into the interior of the main body 2 (see FIGS. 2 and 4). In this state, a rectangular ready-made concrete bottom plate 6 is lowered and placed on the foundation 3 using a crane or the like. A reinforcing bar 7 is made to protrude from the outer surface of the bottom plate 6, and a gap t is interposed between this outer surface and the inner surface of the main body 2, and the bolt 5 and the protruding reinforcing bar 7 are connected within the gap t. Connected into one body by welding. There is no problem even if the screwing operation of the bolts 5 is performed after the bottom plate 6 is lowered onto the foundation 3. After pouring mortar or ready-mixed concrete 9 into the gap t to the same level as the bottom plate 6, as shown in FIG.
After placing the top plate 13 on the upper end opening and fixing it with bolts 14, the top plate 13 is covered with soil 15 and the entrance/exit manhole opening 16 formed on the top plate 13 is opened in the soil covering 15. In addition, the part indicated by 17 in the figure is the underground conduit connection,
18 is a water collection pit.

"Effects" Since the present invention is constructed as described above, not only can the burying work of the manhole main body 2 be carried out safely and quickly, but also the concrete bottom surface and foundation 3 formed by the lower part of the manhole main body 2, the bottom plate 6 and the gap concrete 9 can be buried.
A stable manhole with strong bonding force is formed during construction.

[Brief explanation of the drawing]

Figure 1 A, B, H, D, H, F is a side view showing an embodiment of the process of the manhole installation method of the present invention, Figure 2 is a side view of the bottom plate connected state, and Figure 3 is the same as in Figure 2. A plan view, FIG. 4 is a perspective view of the manhole body, FIG. 5 is a perspective view of a ready-made concrete plate, and FIG. 6 is a perspective view of the top plate. 1...Blade opening, 2...Manhole body, 3...Foundation, 4...Female screw hole, 5...Bolt, 6...Ready-made concrete bottom plate, 7...Reinforcing bar, 8...Welded part, t
...Gap, 9...Concrete.

Claims (1)

[Claims] 1. After lowering the manhole body with a cutting edge formed on the lower edge into the ground by excavating and removing soil directly below the cutting edge and removing the earth and sand inside the main body, the foundation is installed at the level of the cutting edge mentioned above. The tips of the bolts are screwed into the female screw holes opened on the inner surface of the main body, and a ready-made concrete bottom plate is placed on the foundation, and the bolts are connected to the reinforcing bars protruding from the outer surface of the bottom plate. A manhole installation method characterized by welding and then pouring concrete into the gap between the inner surface of the main body and the outer surface of the bottom plate.