JP6934723B2 - Box-shaped member of shear transfer structure and shear transfer structure - Google Patents

Description

The present invention is a box-shaped member for constructing a shear transmission structure for transmitting a shear force acting between an underground continuous wall and an underground concrete structure constructed by joining the underground continuous wall, and the box. It relates to a shear transfer structure constructed by using a mold member.

For the floating that acts on the bottom slab of underground concrete structures such as LNG underground storage tanks at high water levels, the load that is insufficient only by the skeleton weight of the underground concrete structure is positively applied to the weight of the continuous underground wall and the pull-out resistance. The method of using and resisting is adopted. In order to utilize the resistance of the underground continuous wall constructed as a retaining wall on the outer circumference of the underground concrete structure, a method of driving a large number of gibber bars into the wall surface of the underground continuous wall and using it as a shear transmission member has long been used. Has been used.
However, since the method involves complicated work, the workability is poor, and there is a big problem in terms of cost and process.

Therefore, in recent years, a method of transmitting a shear force acting between an underground continuous wall and an underground concrete structure constructed by joining the underground continuous wall by a shear transmission structure using a shear key has been widely used.

Specifically, Patent Document 1 describes in the underground between the top of the side wall and the top of the continuous underground wall in an LNG underground storage tank in which a continuous underground wall is constructed around a side wall forming a part of the tank frame. A shear transmission force structure including a circumferential groove formed on the inner peripheral surface of the continuous wall top and a protruding shear key formed on the outer peripheral surface of the side wall top so as to fit in the circumferential groove is disclosed.

Further, in Patent Document 2, as a method for constructing the shear transmission structure as described above, after inserting a reinforcing bar cage in which a concave portion, which is a formwork member of the shear transmission structure, is arranged and fixed, into a continuous underground wall. , A method of pouring concrete or the like while discharging muddy water or the like and removing the hardened concrete or the like that has flowed into the concave portion when excavating the ground inside the continuous underground wall is disclosed.

Japanese Unexamined Patent Publication No. 9-177360 Japanese Unexamined Patent Publication No. 2002-47670

When the shear transfer structure is to be constructed by the method as in Patent Document 2, since the concrete or the like hardened in the concave portion is to be lifted, the removed concrete is carried out and disposed of.
On the other hand, in order to prevent concrete from entering the concave part, a method of laying styrofoam in advance is also used, but a large amount of construction waste is generated due to the work of taking out the styrofoam, carrying it out, and disposing of it. There is no change.

Therefore, in order to prevent the inflow of concrete, a method is adopted in which the formwork shape of the shear transmission structure construction portion is not a concave shape but a box shape. With this method, concrete does not flow into the boxing member, a space with a predetermined shape and size required for shear transmission can be secured, and construction waste such as concrete and styrofoam after removal is not generated. It can be said that it is an excellent method in terms of points.

However, even with the method using the box-extracting member, since all four sides are sealed with steel plates, it acts on the hydraulic pressure of a stabilizing liquid such as muddy water in the continuous underground wall and when placing concrete. In order to resist lateral pressure, there is a problem that excessive reinforcement is required on the inner surface side of the steel plate constituting the box punching member.

Therefore, an object of the present invention is to provide a box-shaped member that does not require excessive reinforcement and a shear transfer structure constructed by using the box-shaped member.

In order to solve the conventional problems as described above, the feature of the invention according to claim 1 is the shear acting between the continuous underground wall and the concrete structure constructed along the inner surface of the continuous underground wall. A box-shaped member for constructing a shear transmission structure for transmitting force, the box-shaped member is a closed hollow container, and is fixed at a predetermined position on the inner surface side of a reinforcing bar cage of the continuous underground wall. is that the insertion hole is provided in the upper side and lower side of the filling can be the box-type member said stabilizer when inserting the iron muscle basket to a stable liquid filled drilling grooves inside the box-type member ..

The feature of the invention according to claim 2 is that, in addition to the configuration of claim 1, the size of the insertion hole is smaller than the diameter of the coarse aggregate of concrete.

The feature of the invention according to claim 3 is that, in addition to the configuration of claim 1 or 2, the insertion holes are provided at a plurality of places so as to also serve as air vents.

The feature of the invention according to claim 4 is a shear transfer structure constructed by using the box-shaped member according to claims 1 to 3.

According to the box-shaped member and the shear transmission structure of the shear transmission structure of the present invention, the hydraulic pressure due to the stabilizing liquid such as muddy water and the lateral pressure at the time of placing concrete are countered without generating construction waste such as concrete and foamed styrol. Therefore, excessive reinforcement is not required, and a box-shaped member for constructing a shear transmission structure can be constructed with only a simple member, and a shear transmission structure using the box-shaped member can be constructed.

(A) A front view of the box-shaped member of the present invention, and (b) a side view of the box-shaped member of the present invention. It is a figure of the attachment situation to the reinforcing bar basket of the box-shaped member of this invention. It is a lifting situation diagram of a reinforcing bar cage. (A) A diagram of the completion of building a reinforcing bar cage in the underground continuous wall, (b) a diagram of the status of placing concrete in the underground continuous wall, and (c) a diagram of the lateral pressure acting on the box-shaped member of the present invention. This is the completion status of excavation on the inner surface side of the continuous underground wall. It is a situation diagram after removing the lid part of the box-shaped member of this invention. It is a diagram of the completion of construction of an underground concrete structure.

Hereinafter, embodiments of the box-shaped member and the shear transfer structure of the present invention will be described with reference to the drawings.
FIG. 1 is a structural schematic view (a) front view and (b) side view of the box-shaped member of the present invention.
From the figure, the box-shaped member 1 is composed of a recess 11, a side portion 12, a lid portion 13, which is a steel plate having a thickness of 9 mm, and anchor portions 14, 14 ...
The recess 11 is composed of a U-shaped portion 111 and a fixing portion 112. Since the shear transmission structure 63 described later is constructed on the inner surface of the U-shaped portion 111, the opening side thereof is arranged so as to be the side wall 62 side of the concrete structure 6 described later. The U-shaped portion 111 has a shape that expands toward the opening side, and the fixing portion 112 is arranged so as to be located on a substantially outer surface of the side wall 62 (a substantially boundary surface with the underground continuous wall 5 described later). Although the U-shaped portion 111 and the fixing portion 112 are integrally members that have been bent, they may be configured by connecting different members.
The side portion 12 is connected to the U-shaped portion 111 so as to close the side surface, and the lid portion 13 is connected to the U-shaped portion 111 or the fixing portion 112 and the side portion 12 so as to close the opening.
Since the anchor portions 14, 14 ... Are embedded in the underground continuous wall 5, one end thereof is fixed to the underground continuous wall 5 side of the fixing portion 112.
The strength and dimensions of the steel plate and the deformed reinforcing bar are appropriately determined by the design, but are not limited. In principle, each member is joined by welding, but the connection method is not limited to welding as long as it has a predetermined yield strength and a predetermined box-out dimension, and each member may be integrated.

Insertion holes 15, 15, 15, 15 are provided at the corners of the lid portion 13. Each insertion hole 15 may have a size that allows the stabilizer 41 described later to flow positively and inhibits the inflow of the concrete 42. The shape, number, and arrangement of the insertion holes 15 (not necessarily provided in the lid 13) are not limited, but it is desirable that the insertion holes 15 have dimensions that do not allow the coarse aggregate of the concrete 42 to pass through. Further, it is desirable to provide at least two insertion holes 15 above and below the box-shaped member 1 when the rebar cage 2 has been built so that air does not collect inside the box-shaped member 1.

FIG. 2 is a diagram showing how the box-shaped member 1 of the present invention is attached to the reinforcing bar cage 2.
From the figure, each box-shaped member 1 is placed and fixed on the vertical bars 21, 21 ..., The horizontal bars 22, 22 ... On the side wall 62 side of the reinforcing bar cage 2. As a fixing method, there is a method of welding and fixing to a frame member or the like for maintaining the shape of the reinforcing bar cage 2, but the arrangement does not change even if various external loads such as the hydraulic pressure of the stabilizing liquid and the lateral pressure of the concrete are applied. It is not particularly limited as long as it is fixed to.
It is desirable that the anchor portions 14, 14 ... Are inserted to the inside of the reinforcing bar cage 2.

FIG. 3 is a lifting situation diagram of the reinforcing bar cage 2. In order to maintain the shape of the reinforcing bar cage 2, a shape-retaining material 23 is arranged as needed. Further, above the reinforcing bar cage 2, hanging jigs 24, 24 ... For lifting work are provided, and the hanging jigs 24, 24 ... And the girder 32 are wires (1) 31, 31. ..., One end of the wire (2) 33, 33 ... Is fixed to the girder 32, and the other end is lifted by using a lifting machine such as a crane to lift the entire reinforcing bar cage 2. Can be done.

FIG. 4A shows an excavation ditch 4 having a predetermined depth and a planar shape in the ground G in order to construct the underground continuous wall 5, and after the completion of the construction of the reinforcing bar cage 2 in the excavation ditch 4. It is a side view of.
From the figure, in order to counter the earth pressure of the ground G and the water pressure of the groundwater W, the stabilizer 41 is maintained at a predetermined height in the excavation ditch 4.
Due to the stabilizing liquid 41, a hydraulic pressure 41a corresponding to the attachment depth of the box-shaped member 1 acts on the inner and outer surfaces of the box-shaped member 1. At the same time as the reinforcing bar cage 2 is inserted into the stabilizing liquid 41, the stabilizing liquid 41 flows into the box-shaped member 1 from the insertion hole 15, so that the hydraulic pressure 41a acting on the inner and outer surfaces of the box-shaped member 1 is balanced. Because it will be.

FIG. 4B is a side view showing a state in which the concrete 42 is placed in the excavation ditch 4.
From the figure, according to the casting height of the concrete 42, the lateral pressure 42a of the concrete 42 and the hydraulic pressure 41b of the stabilizing liquid 41 shallower than the casting height of the concrete 42 act on the outer surface of the box-shaped member 1.
FIG. 4C is a conceptual diagram of the lateral pressure 42a and the hydraulic pressure 41b acting on the inner and outer surfaces of the box-shaped member 1 shown in FIG. 4B. A predetermined lateral pressure 42a and hydraulic pressure 41b according to the installation depth of the box-shaped member 1 and the casting height of the concrete 42 act on the outer surface of the box-shaped member 1, and the stabilizing liquid 41 acts on the inner surface of the box-shaped member 1. Since the hydraulic pressure 41b acts on the outer surface of the box-shaped member 1, only the lateral pressure 42a, which is the difference between them, acts on the outer surface of the box-shaped member 1. The box-shaped member 1 is designed with the assumed side pressure 42a as an external load.
In the design, only the lateral pressure 42a due to the concrete 42 is considered, but from the safety side, the design can be made in consideration of the load caused by other factors as necessary.

FIG. 5 is a bird's-eye view showing the excavation completion status on the inner surface side of the underground continuous wall 5.
From the figure, the underground continuous wall 5 is configured by alternately connecting the leading element 51 and the trailing element 52. On the inner surface side of the underground continuous wall 5, a box punch is formed by a predetermined number of box-shaped members 1 at a predetermined depth.

FIG. 6 is a bird's-eye view showing a situation in the vicinity of the box-shaped member 1 of the present invention in FIG. A water leakage prevention member 53 for preventing water leakage is laid at the boundary between the leading element 51 and the trailing element 52, if necessary. The water leakage prevention member 53 generally covers the boundary surface with a non-woven fabric or the like, and is fixed to the underground continuous wall 5 with a cut anchor or the like.
The box-shaped member 1 has the lid portion 13 for preventing the inflow of the concrete 42 removed. A shear transmission structure 63, which will be described later, is formed along a box-shaped shape surrounded by a U-shaped portion 111 and a side portion 12 of the recess 11.

FIG. 7 is a side view showing the completion status of the construction of the underground concrete structure.
From the figure, a shear transmission structure 63 constructed by unboxing the bottom slab 61, the side wall 62, and the box-shaped member 1 provided at predetermined positions of the side wall 62 and the side wall 62 is shown. In order to transmit the lifting action force generated in the underground concrete structure to the underground continuous wall 5 at a high water level, it is necessary to insert a shear reinforcing bar (not shown) inside the shear transmission structure 63. Further, the shear transfer structure 63 is not provided at the lower end of the shear transfer structure 63 in order to prevent an action force other than the lifting action force at a high water level, for example, an action force associated with the subsidence of the underground concrete structure, from acting. It is desirable to provide the illustrated cushioning material in advance. Examples of the cushioning material include foamed plastic having a thickness of about 50 mm, but the material, shape, and dimensions are not limited as long as the transmission of shearing force can be inhibited.

According to the box-shaped member and the shear transmission structure of the shear transmission structure of the present invention, the hydraulic pressure due to the stabilizing liquid such as muddy water and the lateral pressure at the time of placing concrete are countered without generating construction waste such as concrete and foamed styrol. Therefore, excessive reinforcement is not required, and a box-shaped member for constructing a shear transmission structure can be constructed with only a simple member, and a shear transmission structure using the box-shaped member can be constructed.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and even if there is a change or the like within a range that does not deviate from the gist of the present invention. , They are included in the present invention.

1 Box-shaped member 11 Recession 111 U-shaped part 112 Fixing part 12 Side part 13 Lid part 14 Anchor part 15 Insertion hole 2 Reinforcing bar cage 21 Vertical bar 22 Horizontal bar 23 Shape-retaining material 24 Hanging jig 3 Hanging device 31 Wire (1)
32 girder 33 wire (2)
4 Excavation ditch 41 Stabilizer 41a, 41b Hydraulic pressure 42 Concrete 42a Side pressure 5 Underground continuous wall 51 Leading element 52 Trailing element 53 Leakage prevention member 6 Concrete structure 61 Bottom slab 62 Side wall 63 Shear transmission structure G Ground W Groundwater

Claims (4)

A box-shaped member for constructing a shear transmission structure that transmits a shear force acting between an underground continuous wall and a concrete structure constructed along the inner surface of the underground continuous wall.
The box-shaped member is a closed hollow container, which is fixed at a predetermined position on the inner surface side of the reinforcing bar cage of the continuous underground wall, and is stable when the reinforcing bar cage is inserted into the stabilizing liquid filled in the excavation groove. a box-shaped member, characterized in that the liquid is insertion hole provided in the upper side and lower side of the filling can be the box-type member inside the box-type member. The box-shaped member according to claim 1, wherein the size of the insertion hole is smaller than the diameter of the coarse aggregate of concrete. The box-shaped member according to claim 1 or 2, wherein the insertion holes are provided at a plurality of locations so as to also serve as air vents. A shear transfer structure constructed by using the box-shaped member according to claim 1 to 3.

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