JP3777549B2 - Synthetic underground wall, its construction method, and water expansion waterproofing material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic underground wall having a structure in which a reinforced concrete wall is integrated on the front side of a columnar underground wall such as a soil mixing wall, a construction method thereof, and a reinforcing bar embedded in a concrete wall that requires water-stopping. It is related with the water expansion waterproofing material used by attaching to.
[0002]
[Prior art]
As is well known, Soil Mixing Wall (hereinafter referred to as SMW) is a columnar underground wall built on site and generally agitates the ground to a predetermined depth with a multi-axis auger excavator. While excavating, cement-based solidified material is poured into the ground and kneaded together with the ground, and after raising the auger, a core material made of steel such as H-shaped steel is built and hardened. This construction method can be constructed at low cost because there is little drainage, and has been widely used as a retaining wall or a water blocking wall.
[0003]
By the way, in the past, the columnar underground wall such as SMW was provided only as a temporary mountain retaining or water blocking wall, and was not used as a main building. Use as part of a wall is being considered. FIG. 4 shows an example. After excavating the front side of the SMW 1 formed as a temporary mountain retaining or water blocking wall, the stud 3 is fixed to the steel frame (H-shaped steel) which is the core material 2 of the SMW 1 by welding. The SMW 1 and the RC wall are connected via the stud 3 by doublely arranging the wall bars 4 on the front side of the SMW 1 and placing concrete 5 to form a reinforced concrete wall (hereinafter referred to as RC wall) 6. 6 is formed to form a synthetic basement wall 7 of a permanent construction. According to such a synthetic underground wall 7, the temporary SMW 1 can be used as it is as a part of the main wall as it is, which is reasonable, and the required strength of the RC wall 6 can be reduced by the amount that the strength of the SMW 1 can be expected. As a result, the wall thickness can be reduced and the construction cost can be reduced as a whole.
[0004]
[Problems to be solved by the invention]
However, in the conventional synthetic underground wall 7, when the RC wall 6 is constructed, the concrete 5 is not sufficiently filled around the stud 3, and a gap is generated between the peripheral surface of the stud 3 and the concrete 5. In this case, it is assumed that the water stoppage of the RC wall 6 cannot be sufficiently secured.
[0005]
In addition, when the synthetic underground wall 7 is positively bent (inner side = deformation that curves toward the RC wall 6 side), the RC wall 6 generates compressive stress as a whole, so there is little fear of cracking. On the other hand, when negative bending (deformation that curves to the outside = SMW1 side) occurs, there is room for tensile stress on the back side of the RC wall 6 to cause cracks. When this occurs, it is assumed that sufficient water-stopping cannot be ensured.
[0006]
In view of the above circumstances, an object of the present invention is to provide an effective means for preventing a decrease in water stoppage due to the above-described factors in a composite underground wall of a columnar underground wall such as SMW and an RC wall. To do.
[0007]
[Means for Solving the Problems]
The invention of claim 1 is a composite underground wall having a structure in which a reinforced concrete wall is integrated on the front side of a columnar underground wall, and a stud for integrating the columnar underground wall and the reinforced concrete wall is a columnar column. It is fixed to the steel frame, which is the core material of the underground wall, and is embedded in the reinforced concrete wall, and the stud is provided with an annular water expansion waterproofing material, and the columnar underground wall and the reinforced concrete wall The boundary surface is characterized in that a water-stop sheet or a paint-based waterproofing material is interposed at a position where tensile stress is assumed to occur at least in the reinforced concrete wall.
[0008]
The invention of claim 2 is a method of constructing a synthetic underground wall having a structure in which a reinforced concrete wall is integrated on the front side of a columnar underground wall, and the columnar underground wall is provided in the ground, and the front side is provided. When excavating and exposing the surface of the steel frame, which is the core material of the columnar underground wall, and fixing the stud with the annular water expansion waterproofing material to the surface of the core material, at least when tensile stress occurs on the reinforced concrete wall At the assumed position, a waterproof sheet or a waterproof coating material is attached to the front of the columnar underground wall, and then a wall is placed on the front side of the columnar underground wall to assemble the formwork and concrete It is characterized by forming a reinforced concrete wall by casting.
[0009]
The invention of claim 3 is a water expansion waterproofing material used by attaching to a reinforcing bar embedded as a stud or the like in a concrete wall that requires waterproofing, and has an annular shape having a central hole through which the reinforcing bar is inserted, And it is characterized by making 3 layer structure which laminated | stacked the water expansion | swelling rubber layer on the inner peripheral side and outer peripheral side of a non-expanded rubber layer, respectively.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a structure of a synthetic underground wall 10 according to an embodiment of the present invention. In FIG. 1, reference numeral 11 is an SMW (soil mixing wall) which is a columnar underground wall constructed with H-shaped steel as a core material 12, and 13 is an RC wall (reinforced concrete wall) provided integrally on the front side thereof. . The SMW 11 in this example is composed of column rows arranged in a staggered manner, and the front side thereof is excavated into an uneven shape according to the column rows, and therefore, the back side of the RC wall 13 is naturally formed in a shape that follows the uneven shape. The RC wall 13 is integrated with the concave and convex portions of both sides engaged.
[0011]
Similar to the RC wall 6 in the conventional synthetic underground wall 7 shown in FIG. 4, the RC wall 13 of the present embodiment has a wall bar 14 embedded therein, and a reinforcing bar 15 is embedded as necessary. A stud 16 is welded and fixed to the surface of the H-shaped steel, which is the core material 12 of the SMW 11, and the SMW 11 and the RC wall 13 are reliably integrated by the stud 16. In the present embodiment, the stud 16 is formed by integrally forming a truncated cone-shaped fixing head 16a by thickening the tip of a deformed reinforcing bar or a simple steel bar or the like in a tapered shape. . The thickening process for forming the fixing head 16a is easily and efficiently performed by compressing the end of the reinforcing bar in the axial direction in a state where the end portion of the reinforcing bar is heated by high frequency induction to be red-heated and bulging in the radial direction. It can be carried out. Instead of increasing the thickness of the reinforcing bar, it is also possible to employ a stud having a fixing head made by welding a fixing plate made of a thick steel plate to the end of the reinforcing bar.
[0012]
In this embodiment, the length of each stud 16 is adjusted according to the uneven shape on the back side of the RC wall 13, and the front end of the stud 16 secures a predetermined fog and is close to the surface of the RC wall 13. It is supposed to reach That is, a long stud 16 is used at a position where the back side is a convex part, and a short stud 16 is used at a position where it is a concave part.
[0013]
Further, a water expansion waterproofing material 17 is provided around the base end portion of the studs 16. As shown in FIGS. 2 to 3, the water expansion waterproofing material 17 is an annular member having a center hole 17a through which the stud 16 can be inserted. Water expansion rubber is provided on the inner peripheral side and the outer peripheral side of the non-water expansion rubber layer 17c, respectively. It has a three-layer structure in which the layers 17b and 17d are laminated. Particularly, a rubber layer using vulcanized rubber can be suitably used.
[0014]
The water-expanding water-stopping material 17 is attached to the stud 16 without any gaps due to the elasticity of the non-water-expanding rubber layer 17c, and is embedded in the RC wall 13 together with the stud 16 as it is. Thereby, even if it is a case where the filling property of the ready concrete with respect to the circumference | surroundings of the stud 16 is not enough at the time of concrete placement at the time of forming the RC wall 13, the water expansion rubber layers 17b and 17d are the moisture in the ready concrete. It reacts and expands naturally and prevents the formation of a gap around the stud 16, thereby obtaining excellent water stoppage. In particular, even when the stud 16 is formed of a deformed reinforcing bar, the water expansion rubber layer 17b on the inner peripheral side expands and can reliably adhere to the outer peripheral surface of the stud 16 without a gap, thereby providing a reliable water stop. Yes.
[0015]
In addition, a water stop sheet 18 is interposed at a key point on the boundary surface between the SMW 11 and the RC wall 13. The water-stop sheet 18 has a large adhesion by reaction with a mere rubber sheet, a sheet-shaped laminated water-expanded water-stop material in which a water-expanded vulcanized rubber layer and a non-water-expanded vulcanized rubber layer are laminated, or ready-mixed concrete. A non-vulcanized butyl rubber-based water-proof sheet or the like that can provide power can be suitably used.
[0016]
The water stop sheet 18 may be provided over the entire boundary surface, but at least the RC wall 13 may be provided at a position where a tensile stress due to negative bending is generated and a crack is expected to occur. Then, it is provided in a range excluding the surface of the core material 12. By providing such a water stop sheet 18, even if the RC wall 13 is negatively bent and cracked, it is ensured that the water stop sheet 18 ensures water stop performance and causes water leakage. Can be prevented. In addition, as shown in FIG. 1, it is preferable to provide a drain pipe 19 on the back side of the water stop sheet 18 if necessary. Moreover, it can replace with the water stop sheet | seat 18, and the same effect is acquired also by providing a coating-film type | system | group waterproofing material (for example, chloroprene rubber type thing).
[0017]
In order to construct the synthetic underground wall 10, the SMW 11 is constructed by a normal construction method, and then the front side is excavated to expose the surface of the core material 12. Then, a waterproof sheet 18 is attached to a necessary portion by adhesion or the like, or a waterproof coating material is provided in place of the waterproof sheet 18, and the stud 16 provided with the water expansion waterproof material 17 is welded to the core material 12. Install by. When the waterstop sheet 18 is also attached to the surface of the core member 12, the surface of the SMW 11 is washed with a sand blaster or a high pressure water washer, and the waterstop sheet 18 has a hole at a position where the stud 16 is to be attached. Alternatively, a notch may be formed, and the stud 16 may be passed through the hole or notch and attached to the core member 12, and then a waterproof sheet piece may be stacked on the base of the stud 16 and sealed. Thereafter, the wall bars 14 and reinforcing bars 15 are arranged as usual, the formwork is built, concrete is placed, and the formwork is disassembled after a predetermined curing period to complete.
[0018]
According to the synthetic underground wall 10 described above, since the water expansion waterproofing material 17 is provided around the stud 16, the water expansion waterproofing material 17 is used to prevent the concrete from filling the periphery of the stud 16. Since the water-stop sheet 18 or the coating-type waterproof material is provided at a position where water performance is ensured and at least there is a concern that tensile stress may occur, the water-stop sheet is provided even if the RC wall 13 is cracked. 18 or a waterproof coating material ensures waterproofing performance. From the above, this synthetic underground wall 10 is extremely excellent in water-stopping properties, and greatly improves the reliability of this type of synthetic underground wall against water-stopping. Can do.
[0019]
In the present invention, it is preferable to use the stud 16 in which the fixing head 16a is integrally molded as shown in the above embodiment. However, the annular water expansion waterproofing material 17 having the same function can be mounted. Other types of studs may be used as long as they are suitable. Moreover, although SMW11 was employ | adopted as a column-column-type underground wall in the said embodiment, if a steel frame is used as the core material 12, another column-column-type underground wall is also employable. Furthermore, the water expansion waterproofing material of the present invention can be widely applied not only to the synthetic underground wall 10 as in the above embodiment, but also to all reinforcing bars embedded as studs or the like in a reinforced concrete wall that requires water blocking. Is.
[0020]
【The invention's effect】
Since the synthetic underground wall of the invention of claim 1 is provided with an annular water expansion / stop material attached to the stud fixed to the core material of the columnar type underground wall and embedded in the reinforced concrete wall on the front side thereof, Even if the concrete is not sufficiently filled in the surrounding area, water-stopping is ensured there, and at the necessary part of the interface between the columnar underground wall and the reinforced concrete wall, at least tensile stress may occur. Since a waterproof sheet or paint-based waterproofing material is interposed at the assumed position, even if cracks occur in the reinforced concrete wall, waterproofing is ensured by the waterproof sheet or paint-based waterproofing material, Therefore, the water stoppage of the entire synthetic underground wall can be improved.
[0021]
In the construction method of the synthetic underground wall of the invention of claim 2, the columnar underground wall is provided, the front side thereof is excavated, the surface of the steel frame as the core material is exposed, and the water-expanded water-stopping material is mounted. Reinforced concrete walls by fixing the studs, attaching a waterproof sheet or waterproof coating material at the position where at least tensile stress is expected, placing the wall reinforcement, assembling the formwork and placing the concrete Therefore, it is possible to efficiently construct a synthetic underground wall having excellent water blocking properties.
[0022]
The water expansion waterproofing material of the invention of claim 3 has an annular shape having a central hole through which a reinforcing bar is inserted, and has a three-layer structure in which a water expansion rubber layer is laminated on each of an inner peripheral side and an outer peripheral side of a non-expanded rubber layer. Therefore, even if the concrete fillability around the reinforcing bar is not sufficient, it is secured by using it attached to the reinforcing bar embedded as a stud in the concrete wall where waterproofing is required. can do.
[Brief description of the drawings]
FIG. 1 is a plan sectional view of a synthetic underground wall according to an embodiment of the present invention.
FIG. 2 is a view showing a state in which a stud and a water stop sheet are attached to the core material of the soil mixing wall.
FIG. 3 is a view showing a water expansion waterproofing material that is attached to a stud.
FIG. 4 is a diagram showing an example of a conventional synthetic underground wall.
[Explanation of symbols]
10 Synthetic underground wall 11 Soil mixing wall (columnar wall)
12 Core material (steel frame)
13 Reinforced concrete walls (RC walls)
14 Wall reinforcement 15 Reinforcement reinforcement 16 Stud 16a Fixing head 17 Water expansion waterproofing material 17a Center hole 17b, 17d Water expansion rubber layer 17c Non-water expansion rubber layer 18 Water stop sheet 19 Drain pipe

Claims (3)

A composite underground wall with a structure in which a reinforced concrete wall is integrated on the front side of the columnar basement wall, and the stud for integrating the columnar basement wall and the reinforced concrete wall is the core of the columnar basement wall It is fixed to a certain steel frame and embedded in a reinforced concrete wall, and its stud is provided with an annular water expansion waterproofing material, and at least the reinforced concrete wall at the interface between the columnar underground wall and the reinforced concrete wall A synthetic underground wall, characterized in that a waterproof sheet or a coating-type waterproofing material is interposed at a position where tensile stress is assumed to occur. This is a method of constructing a composite underground wall with a structure in which a reinforced concrete wall is integrated on the front side of a columnar underground wall. A columnar underground wall is provided in the ground, and the front side is excavated. The surface of the steel frame, which is the core material of the wall, is exposed, a stud with an annular water expansion and waterproof material is fixed to the surface of the core material, and at least a column at a position where tensile stress is expected to occur in the reinforced concrete wall Reinforced concrete by attaching a waterproof sheet or waterproofing coating to the front of the row-type underground wall, and then placing the wall reinforcement on the front side of the column-type underground wall, assembling the formwork, and placing the concrete A method of constructing a synthetic underground wall characterized by forming a wall. A water-expanding water-stopping material used by attaching to a reinforcing bar embedded as a stud or the like in a concrete wall where water-stopping is required. A water expansion waterproofing material characterized by having a three-layer structure in which a water expansion rubber layer is laminated on each of an inner peripheral side and an outer peripheral side.

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