JPS6240485B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides an underground structure in which a plurality of concrete unit walls are continuously poured underground or connected in a column, and concrete is poured along one side of the concrete unit walls. This paper relates to a prestressing method for continuous walls.

Generally, this type of underground continuous wall is used as an earth retaining wall, a water-stopping wall, or as part of the main body of an underground structure, but it is made by continuously pouring multiple concrete unit walls underground. The underground continuous wall that was formed was
Although the joints have low strength and require a huge amount of cost, as is the case with underground LNG tanks, for example, they are viewed as nothing more than separate upright walls, and improvements have been called for.

Conventionally, methods for reinforcing the joints of concrete unit walls include those that provide shear reinforcing bars or water stop plates at the joints, and those that connect reinforced concrete along one side of the joints, but these methods are difficult to construct. Although it is complicated, time-consuming, and expensive, it goes beyond partial reinforcement and integrates the entire continuous wall including the joints, making it possible to transform the continuous wall, which had previously been separated in terms of strength, into a part of the structure. It has not yet reached the point where it can be used as a continuous wall, and a system has been developed that applies horizontal tightening force to the entire continuous wall by inserting tension members into the wall, but it is difficult to insert the tension members and perform tensioning work, and it is difficult to do so. There were problems such as the need for additional technology.

The present invention has been made in view of the above points, and its purpose is to create new concrete along one side of a wall constructed by continuously pouring concrete unit walls or connecting them in columns. It is possible to strengthen the structure of the entire wall by applying prestress to the concrete, and it can be used as a part of the main body of the structure that can withstand soil water pressure. The purpose of the present invention is to provide a method for prestressing continuous walls.

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows the state in the middle of forming a continuous wall by continuously pouring concrete unit walls 2 into a trench hole 1 excavated underground using a clamshell bucket or bit. A single protrusion 2a having a required length in the vertical direction and extending to a required depth is integrally protruded from one side of the unit wall 2. The projections 2a may be formed at one end (L-shape) or both ends (shape) of the concrete unit wall 2, as illustrated in FIG. Just choose. Further, the continuous wall is not limited to being formed in a straight line as shown in the figure, but may be formed in a circular shape, for example, when constructing an underground LNG tank or the like. In addition, the concrete unit wall 2 of this example
is formed by erecting reinforcing bars as appropriate in trench hole 1 or by pouring concrete without reinforcing bars, but concrete wall unit 2 is formed by forming a concrete wall unit in advance in a factory etc. They may be inserted into the hard groove hole 1 and connected in a vertical line.

Next, the soil on one side of the continuous wall constructed as described above, that is, on the side of the wall where the protrusions 2a are formed, is excavated, and a plurality of horizontal holes 2b are drilled in the protrusions 2a as shown in FIG. etc. to open it. The horizontal hole 2b may be formed in advance by attaching a sheath or the like to the reinforcing bar during the concrete pouring, or it is preferable to already drill it in a precast concrete wall unit. The horizontal holes 2b are arranged so as to be aligned with each other in a substantially horizontal direction.

Next, a third hole is inserted into the horizontal hole 2b arranged as described above.
Insert the sheath 3 as shown in the figure. The sheath 3
is a horizontal hole 2b in a plurality of concrete unit walls 2
The sheaths 3 are inserted in a stitching manner, and each sheath 3 is sequentially shifted horizontally one step at a time as shown in the figure, or arranged in a staggered manner so that the lateral tightening force described below acts evenly over the entire continuous wall. good. Subsequently, a tension member 4 such as a PC wire or a PC steel rod is passed through the sheath 3, and both ends of the tension member 4 are made to protrude from the end surface of the horizontal hole 2b of the protrusion 2a. One end of the tension material 4 is fixed by a fixing means 5 such as a fixing hardware, and a tensioning means 6 such as a jack is attached to the other end.

Next, an appropriate formwork (not shown) is constructed at a predetermined interval from the excavated side of the continuous wall, that is, one side where the tendon material 4 is arranged, and concrete 7 is poured. Incidentally, when pouring the concrete 7, the tensioning means 6 is boxed out. When the concrete 7 hardens, the tensioning means 6 tensions the tendon material 4 to apply tension and grouting is performed inside the sheath 3. After the concrete 7 hardens, the tensioning means 5 and the tensioning means 6 are attached to both ends of the tendon material 4. is released to give prestress.

In the above embodiment, after the concrete 7 is placed and hardened, the tension material 4 in the sheath 3 is tensioned to give prestress to the concrete 7. However, as shown in FIG. The tension member 4 is inserted through the tension member 4 and tensioned by the tension means 6 attached to one end thereof, and the concrete 7 is poured as shown in FIG. 4, and the concrete 7 hardens and reaches a predetermined strength. Thereafter, the fixing means 5 and the tensioning means 6 may be opened to apply prestress to the concrete 7, thereby applying prestress to the concrete 7.

As described above, the present invention connects new concrete to one side of a concrete unit wall and integrally strengthens it by applying prestress using the tension of the tendon material. The medium continuous wall can be used as a part of the structure, and the construction as a whole is simple, quick, and inexpensive.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the state in which a concrete unit wall is formed in a trench hole excavated underground, Figure 2
FIG. 3 is a perspective view showing a state in which a horizontal hole is bored in the protrusion; FIG. Fig. 4 is a perspective view showing a state in which new concrete has been poured, Fig. 5 is a perspective view of the embodiment of the second invention showing a state in which tendons are inserted and placed in horizontal holes, and Fig. 6 is a concrete unit. FIG. 7 is an end view showing another example of the protrusion of the wall. 1... Hard groove hole, 2... Concrete unit wall,
2a... protrusion, 2b... horizontal hole, 3... sheath, 4... tension material, 6... tension means, 7... concrete.

Claims (1)

[Scope of Claims] 1. A continuous wall is formed by continuously pouring or connecting a plurality of concrete unit walls in a column in the ground, and the required vertical direction is provided on one side of each concrete unit wall. At least one protrusion having a length is integrally formed to protrude, and a plurality of horizontal holes are bored in the protrusion, and at least the horizontal holes of adjacent concrete unit walls are arranged substantially horizontally to each other. The sheaths are inserted into these aligned horizontal holes, and tensioning materials such as prestressed steel are inserted into the sheaths, and both ends of the sheaths are connected to the fixing and tensioning means provided with the projections. Installation, pour concrete along the side wall surface where this tendon is placed,
After the concrete has hardened, tension is applied to the tendons by the tensioning means, and finally, grouting is performed within the sheath, and after the concrete has hardened, the anchoring and tensioning means are released to apply prestress to the concrete. A prestressing method for underground continuous walls characterized by the following. 2. A continuous wall is formed by continuously connecting a plurality of concrete unit walls underground or in a column, and at least one concrete unit wall has a required length in the vertical direction on one side of each concrete unit wall. The protrusions of the strips are integrally formed in a protruding manner, and a plurality of horizontal holes are bored in the protrusions, and the horizontal holes of at least adjacent concrete unit walls are arranged so as to be aligned with each other in a substantially horizontal direction. Then, insert a tension material such as prestressing steel material into these aligned horizontal holes, and attach both ends to the fixing and tensioning means provided on the projection, and apply tension to the tension material by the tensioning means. An underground continuous wall characterized in that concrete is poured along the side wall surface where the tendon material is arranged, and after the concrete hardens, the fixing and tensioning means is released to apply prestress to the cemented concrete. prestressing method.