JP2012122190A - Underground structure and construction method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground structure which is formed by connecting a core material in an earth retaining wall with a RC skeleton and which can perform exposure work of a core material simply and quickly.SOLUTION: An underground structure is formed by connecting a core material 1 in an earth retaining wall W with a RC skeleton S, and the core material 1 is provided with a skeleton side flange 11 having a reinforcement insertion hole, a natural ground side flange 12 facing the skeleton side flange 11, a reinforcement for core material 2 fixed to the natural ground side flange 12 and a coupler for mechanical joint 3 fitted to the reinforcement for core material 2. The coupler 3 is arranged between the skeleton side flange 11 and the natural ground side flange 12, and the RC skeleton S has an anchoring reinforcement 4 reaching the core material 1, and the anchoring reinforcement 4 is connected with the coupler 3 through the reinforcement insertion hole.

Description

  The present invention relates to an underground structure formed by connecting an RC frame to a core material of a mountain retaining wall, and further relates to a method for constructing this kind of underground structure.

  As disclosed in Patent Document 1, there is a case where an RC frame (a reinforced concrete frame) is connected to the core material of the mountain retaining wall and a part of the force acting on the RC frame is borne on the mountain retaining wall.

  The technique disclosed in Patent Document 1 is to build a mountain retaining wall by building a core material in which a core reinforcing bar is incorporated into the ground, expose the core material by digging the ground, and then rebar the core material. A coupler for a mechanical joint is attached to the RC, and the reinforcing bar of the RC housing is connected to the reinforcing bar for the core material through the coupler. In addition, the reinforcing rod for core material is penetrated by the ground-side flange and the frame-side flange of the core material, and one end of the reinforcing rod for core material is fixed to the ground-side flange. The other end of the core reinforcing bar protrudes from the housing side flange, and a coupler is connected to the protruding portion.

Japanese Patent No. 2673634

  In the technique of Patent Document 1, it is necessary to perform an operation of exposing the frame side flange (an operation to remove earth and sand surrounding the core material, soil cement, etc.). There is a risk of becoming.

  From such a viewpoint, the present invention is an underground structure in which an RC frame is connected to a core material of a mountain retaining wall, and the work for exposing the core material can be performed easily and quickly. It is an object to provide a structure, and further to provide a method for constructing such an underground structure.

  The underground structure according to the present invention is an underground structure formed by connecting an RC frame to a core material of a mountain retaining wall, and the core material includes a frame side flange having a reinforcing bar insertion hole, and the frame side. A natural ground flange facing the flange, a core rebar fixed to the natural flange, and a coupler for a mechanical joint attached to the core rebar, the coupler comprising the body It is arranged between a side flange and the natural ground side flange, and the RC housing is provided with a fixing reinforcing bar that reaches the core material, and the fixing reinforcing bar passes through the reinforcing bar insertion hole to the coupler. It is connected.

  When constructing an underground structure according to the present invention, a core material incorporating a coupler (sometimes referred to as a sleeve) and a core reinforcing bar is built in the ground, and the core material is used. After constructing the mountain retaining wall, the RC reinforcing bar fixing rods will be connected to the coupler, but the core reinforcing bar and coupler do not protrude from the frame side flange, so the work to expose the frame side flange (core In the operation of removing earth and sand surrounding the material, soil cement, and the like, the core reinforcing bars and couplers do not hinder the operation.

  In the underground structure according to the present invention, a sealing material may be interposed between the coupler and the housing side flange. If it does in this way, it will become possible to prevent the water leak from a reinforcing-bar insertion hole.

  When a female screw is formed on the coupler and a male screw is formed on the fixing reinforcing bar, a water stop nut is screwed onto the male screw on the RC housing side of the housing side flange. A sealing material may be interposed between the water-stop nut and the housing-side flange, or a waterproofing treatment may be performed on the water-stop nut and the fixing rebar. If it does in this way, it will become possible to prevent the water leak from a reinforcing-bar insertion hole. In addition, if a sealing material is interposed between the coupler and the housing side flange in addition to the water stop nut and the housing side flange, compared to the case where the sealing material is arranged only on either side, The water stop performance is improved.

  An underground structure construction method according to the present invention is a method of constructing an underground structure in which an RC frame is connected to a core member of a mountain retaining wall, wherein the frame side flange and the ground mountain side flange of the core member are provided. A mechanical joint coupler between the coupler and the core-side flange from the coupler to the ground-side flange is fixed to the ground-side flange, and the reinforcing bar insertion hole formed in the housing-side flange The shaft portion of the temporary bolt is inserted, the shaft portion is screwed into the coupler, the core material is built in the ground with the coupler being closed by the temporary bolt, and the ground side flange is dug down to the ground side flange. Is exposed, and, instead of the temporary bolts, fixing reinforcing bars reaching the RC frame are inserted into the reinforcing bar insertion holes and connected to the coupler, and then the concrete of the RC frame is placed. Features.

  According to the present invention, since the core reinforcing bar and the coupler for the mechanical joint do not protrude from the casing side flange, the core reinforcing bar and the coupler obstruct the operation when the casing side flange is exposed. Never become. In the present invention, although the head of the temporary bolt protrudes from the housing side flange, the amount of protrusion is small, so that the work is not greatly affected.

  According to the present invention, it is possible to easily and quickly carry out the operation of exposing the housing side flange.

(A) is a cross-sectional view of the underground structure which concerns on embodiment of this invention, (b) is the BB sectional drawing of (a). It is a top view for demonstrating the structure of a core material. It is a figure for demonstrating the construction procedure of the underground structure which concerns on embodiment of this invention, Comprising: (a) is a cross-sectional view which shows the state which constructed | assembled the mountain wall, (b) has exposed the core material FIG. Similarly, (a) is a cross-sectional view showing a state in which a top plate that is an RC frame is constructed, and (b) is a cross-sectional view showing a state in which the bottom of the top plate is dug down.

  The underground structure according to the embodiment of the present invention is formed by connecting an RC housing S to the core material 1 of the mountain wall W as shown in FIGS. FIG. 1A is a cross-sectional view taken along line AA in FIG.

  The mountain wall W is generally a temporary structure, but is used as a permanent structure in this embodiment. If the RC frame S is designed by integrating the RC frame S with the mountain retaining wall W and considering the mountain retaining wall W as a permanent structure, the RC frame S can be slimmed down. It becomes possible to reduce.

  As shown in FIG. 1 (b), the mountain retaining wall W of the present embodiment is a so-called columnar continuous underground wall, and is composed of a plurality of core members 1, 1,... And soil cement. .

  The core material 1 is formed by incorporating a core material reinforcing bar 2 and a mechanical joint coupler 3 into a core material body made of H-shaped steel. That is, the core material 1 is mounted on the core material reinforcing bar 2 fixed to the natural ground side flange 12 and the core material reinforcing bar 2 in addition to the frame side flange 11, the natural ground side flange 12 and the web 13 constituting the core material main body. The coupler 3 is provided. In this embodiment, four core rebars 2, 2,... Are arranged per one core material body, and the coupler 3 is mounted on each of the four core rebars 2, 2,. Of course, I-shaped steel, groove-shaped steel, square steel pipe, etc. may be used as the core material body.

  The housing side flange 11 is disposed so as to face the excavation region (region where the RC housing S is constructed), and the surface of the housing side flange 11 is in contact with the side surface of the RC housing S.

  The natural mountain side flange 12 is arranged so as to face the natural mountain G outside the excavation area. That is, the natural ground side flange 12 is located on the natural ground G side with respect to the structural body side flange 11 and is opposed to the structural body side flange 11.

  As shown in FIG. 2, a reinforcing bar insertion hole 1 a is formed in the housing side flange 11. The natural mountain side flange 12 is formed with a reinforcing bar insertion hole 1 b corresponding to the reinforcing bar insertion hole 1 a of the frame side flange 11. The reinforcing bar insertion holes 1 a and 1 b are formed in accordance with the installation positions of the core reinforcing bar 2 and the coupler 3.

  The web 13 is interposed between the frame side flange 11 and the natural ground side flange 12 and connects the center portions in the width direction of both flanges 11 and 12.

  The core rebar 2 is disposed so as to intersect the natural mountain side flange 12. The core reinforcing bar 2 according to the present embodiment is formed of a threaded reinforcing bar, and is disposed so as to intersect the natural mountain side flange 12 at a right angle and to be parallel to the web 13.

  The core material reinforcing bar 2 of the present embodiment is inserted into the reinforcing bar insertion hole 1b of the ground mountain side flange 12, and the end (hereinafter referred to as "base end part") of the core material reinforcing bar 2 on the ground mountain G side. It protrudes to the outside of the natural ground side flange 12 (the natural ground G side). The proximal end portion of the core reinforcing bar 2 is fixed to the natural ground flange 12 by a pair of fixing nuts 21 and 22 that sandwich the natural ground flange 12. Washers 23 and 24 are interposed between the fixing nuts 21 and 22 and the natural mountain side flange 12. In addition, although illustration is abbreviate | omitted, you may fix the reinforcing bar 2 for core materials to the natural ground side flange 12 by means, such as welding. In this case, the reinforcing bar insertion hole 1b, the fixing nuts 21 and 22 and the washers 23 and 24 of the natural mountain side flange 12 are not necessary.

  The length of the core material reinforcing bar 2 is shorter than the separation distance between the frame side flange 11 and the natural mountain side flange 12, and the end of the core material reinforcing bar 2 on the RC frame S side (hereinafter referred to as "tip portion"). It is located between the frame side flange 11 and the natural ground side flange 12.

  The coupler 3 is disposed between the frame-side flange 11 and the natural ground-side flange 12 in a state where the coupler 3 is attached to the tip of the core reinforcing bar 2.

  The coupler 3 has a cylindrical shape with both ends opened. Inside the coupler 3, a female thread is formed over its entire length. The male screw of the core rebar 2 is screwed into the female screw of the coupler 3 from the natural ground G side. The tip of the core material reinforcing bar 2 remains inside the coupler 3, and the temporary bolt 33 or the fixing reinforcing bar 4 is inserted into the coupler 3 on the side of the housing RCS from the tip surface of the core material reinforcing bar 2. Space to do this is secured. In addition, although illustration is abbreviate | omitted, you may fix the front-end | tip part of the reinforcing bar 2 for cores inside the coupler 3 by means, such as welding.

  The coupler 3 is disposed so as to be adjacent to the housing-side flange 11, and the end surface (hereinafter referred to as “tip surface”) of the coupler 3 on the RC housing S side is abutted against the back surface of the housing-side flange 11. When the coupler 3 is abutted against the housing-side flange 11, the female screw of the coupler 3 communicates with the reinforcing bar insertion hole 1a.

A lock nut 31 is disposed on the opposite side of the housing side flange 11 with the coupler 3 interposed therebetween.
The lock nut 31 is used to prevent the coupler 3 from loosening, and is attached to the core rebar 2. The lock nut 31 is tightened in a direction approaching the coupler 3, and is in close contact with the end face (hereinafter referred to as “base end face”) of the coupler 3 on the ground mountain G side.

A seal material 32 is interposed between the coupler 3 and the housing side flange 11.
The sealing material 32 is disposed for the purpose of preventing water leakage from the reinforcing bar insertion hole 1a, has a ring shape, and is disposed so as to surround the reinforcing bar insertion hole 1a. The sealing material 32 is crushed by the fastening force of the coupler 3 and is in close contact with the front end surface of the coupler 3 and is in close contact with the opening edge of the reinforcing bar insertion hole 1a (the back surface of the housing side flange 11).

  The temporary bolt 33 is disposed for the purpose of preventing earth and sand, a solidified material, and the like from entering the female screw of the coupler 3, and is finally removed. The shaft portion of the temporary bolt 33 is inserted into the reinforcing bar insertion hole 1 a from the RC housing S side and is screwed into the female screw of the coupler 3.

A ring-shaped sealing material 34 is fitted to the shaft portion of the temporary bolt 33.
The sealing material 34 is arranged for the purpose of preventing water leakage from the reinforcing bar insertion hole 1a, has a ring shape, and is arranged so as to surround the reinforcing bar insertion hole 1a. The sealing material 34 is crushed by the fastening force of the temporary bolt 33, and is in close contact with the seating surface of the head of the temporary bolt 33, and is in close contact with the opening edge of the reinforcing bar insertion hole 1a (the surface of the housing side flange 11).

  As shown in FIG. 1A, the RC housing S is a box culvert made of reinforced concrete, and includes a top plate S1 and a side wall S2, but a bottom plate, etc., although not shown. The top plate S1 is provided with a reinforcing bar 4 for fixing to the core material 1 in addition to a main reinforcing bar and a reinforcing bar (not shown).

  The fixing reinforcing bars 4 are arranged at the corners of the RC housing S where a large bending moment is generated, and are connected to the coupler 3 through the reinforcing bar insertion holes 1a (see FIG. 2). The fixing reinforcing bars 4 are arranged after the temporary bolts 33 (see FIG. 2) are removed. The fixing reinforcing bar 4 is a screw joint reinforcing bar, and a male screw is formed over the entire length thereof. The male screw of the fixing reinforcing bar 4 is screwed into the female screw of the coupler 3. Here, when the straight fixing reinforcing bar 4 without bending is used, the position of the fixing reinforcing bar 4 is restricted by the construction accuracy of the core material 1. May affect muscles. In such a case, a fixing reinforcing bar 4 ′ (see FIG. 1B) having a bent portion may be used. In addition, it is good to form a bending part previously in the case of a reinforcing bar process. If the fixing reinforcing bar 4 ′ is used, it can be adjusted to a normal position when it is rotationally inserted into the coupler 3.

  As shown in FIG. 2, a water stop nut 41 and a sealing material 42 are attached to the fixing reinforcing bar 4.

  The water stop nut 41 is screwed into the male screw of the fixing reinforcing bar 4 on the RC housing S side of the housing side flange 11, and the seat surface of the water stop nut 41 is in close contact with the sealing material 42.

  The sealing material 42 is disposed for the purpose of preventing water leakage from the reinforcing bar insertion hole 1a, has a ring shape, and is disposed so as to surround the reinforcing bar insertion hole 1a. The sealing material 42 is crushed by the fastening force of the water stopping nut 41 and is in close contact with the seating surface of the water stopping nut 41, and is in close contact with the opening edge of the reinforcing bar insertion hole 1a (the surface of the housing side flange 11). .

  The axial force acting on the fixing reinforcing bar 4 is transmitted to the frame side flange 11 and the natural ground side flange 12. That is, since the housing-side flange 11 is sandwiched between the coupler 3 screwed into the fixing rebar 4 and the water stop nut 41, the fixing rebar 4 is fixed (fixed) to the housing-side flange 11. Accordingly, the axial force acting on the fixing reinforcing bar 4 is transmitted to the housing-side flange 11. Further, the fixing reinforcing bar 4 is connected to the core reinforcing bar 2 via the coupler 3, and the core reinforcing bar 2 is fixed (fixed) to the ground-side flange. The acting axial force is also transmitted to the natural mountain side flange 12.

  The construction method of the underground structure according to the present embodiment is as follows. In addition, in this embodiment, although the case where the RC housing | casing S is constructed | assembled by a reverse winding method is illustrated, it is not the meaning which limits the construction order of RC housing S.

  As shown in FIG. 3A, first, a mountain retaining wall W is constructed along the outer edge of the excavation region K. Specifically, while excavating the position adjacent to the excavation area with the earth auger, mixing and stirring the excavated soil and cement slurry at the original position to form a soil cement, after lifting the earth auger from the excavation hole, The core material 1 may be built in the ground (excavation hole) before the soil cement is hardened.

  Before building the core material 1 in the ground, the core material reinforcing bar 2 and the coupler 3 are incorporated into the H-shaped steel that is the core material body, and the shaft portion of the temporary bolt 33 is inserted into the reinforcing bar insertion hole of the housing side flange 11. 1a (see FIG. 2) is inserted and the shaft portion is screwed into the coupler 3, so that the female screw of the coupler 3 is closed, and when the core material 1 is built in the ground, a temporary bolt 33 is used. The core material 1 is set in the soil cement with the coupler 3 closed.

  When the mountain wall W is constructed, as shown in FIG. 3 (b), the excavation area K is dug down to a depth where the floor slab S1 can be constructed, and the soil cement on the front side of the frame-side flange 11 is scraped off, The housing side flange 11 is exposed. In this embodiment, although the head of the temporary bolt 33 slightly protrudes from the housing side flange 11, the core reinforcing bar 2 and the coupler 3 are located on the ground mountain G side of the housing side flange 11, and the housing side flange 11 does not protrude, the rebar for core material 2 and the coupler 3 do not hinder the work when the work for exposing the housing flange 11 is performed.

  When the housing-side flange 11 is exposed, the temporary bolt 33 is removed from the coupler 3, and the fixing rebar 4 reaching the corner of the RC housing S is connected to the coupler 3 in place of the temporary bolt 33. Specifically, after attaching the water stop nut 41 and the sealing material 42 to the fixing reinforcing bar 4, the end of the fixing reinforcing bar 4 is inserted into the reinforcing bar insertion hole 1 a (see FIG. 2) and screwed into the coupler 3. do it. Note that a filler such as a grout material may be injected into the coupler 3 as necessary. When the fixing reinforcing bar 4 is connected to the coupler 3, the water stopping nut 41 is tightened, and the sealing material 42 is brought into close contact with the seating surface of the water stopping nut 41 and the opening edge of the reinforcing bar insertion hole 1a.

  In addition, the inside of the reinforcing bar insertion hole 1a (the gap between the hole wall of the reinforcing bar insertion hole 1a and the fixing reinforcing bar 4) and the inside of the water stopping nut 41 (the male screw of the fixing reinforcing bar 4 and the female screw of the water stopping nut 41). A water-stopping material such as an epoxy resin or a grout material may be filled in the gap). If it does in this way, since the water leak which makes the inside of the reinforcing-bar insertion hole 1a and the nut 41 for water stop water will be prevented, water stop performance can be improved further.

  In addition, after tightening the water stop nut 41, a waterproof material such as urethane foam may be sprayed on the proximal end portion of the fixing reinforcing bar 4 and the water stop nut 41. Even if the waterproofing treatment is performed so as to cover the water stop nut 41, water leakage can be prevented from leaking inside the reinforcing bar insertion hole 1a and the water stop nut 41, so that the water stop performance can be improved. it can. Note that the sealing material 42 may be omitted when the spray waterproofing process is performed.

  Although illustration is omitted, the main bar and the distribution bar of the top plate S1 are arranged in parallel with or before and after the connection work of the fixing reinforcing bars 4, and the mold is formed on the lower surface and the wife surface of the top plate S1. Install a frame.

  When the arrangement of the top plate S1 and the formwork are completed, the concrete of the top plate S1 is placed, and after reaching a predetermined strength, the formwork is removed (see FIG. 4A).

  When the top plate S1 is constructed, the excavation area K is dug down below the top plate S1, and a stud or the like is welded to the housing side flange 11 as required (see FIG. 4B). In addition, since the top plate S1 is supported by the core material 1, the temporary intermediate pile etc. which support the top plate S1 can be omitted or reduced.

  After that, when a bottom plate (not shown) is constructed and a side wall S2 is constructed between the top plate S1 and the bottom plate, the RC frame S is connected to the core material 1 of the mountain wall W as shown in FIG. An underground structure is constructed.

  According to the underground structure and the construction method thereof according to the present embodiment, the core rebar 2 and the coupler 3 are connected to the housing side while using the core 1 in which the core rebar 2 and the coupler 3 are preliminarily incorporated. Since it does not protrude from the flange 11, the operation of exposing the housing side flange 11 can be carried out simply and quickly.

  Further, since the fixing reinforcing bar 4 is connected to the coupler, the coupler 3 is fixed to the housing-side flange 11, and the core material reinforcing bar 2 connected to the coupler 3 is fixed to the ground mountain side flange 12. The axial force acting on 4 can be transmitted to the frame side flange 11 and the natural mountain side flange 12, and as a result, the bending moment acting on the corner of the RC frame S can be efficiently transmitted to the core material 1. Become. That is, according to the present embodiment, the bending rigidity of the corner portion of the RC housing S can be efficiently improved.

  Further, since the fixing rebar 4 is fixed to the housing side flange 11 using the coupler 3 and the water stop nut 41, no welding work is required to fix the fixing rebar 4 to the housing side flange 11. become. In addition, when fixing the reinforcing bar 4 to the housing side flange 11 by welding, since it becomes sideways welding, a skilled worker is arranged and high quality control is required, leading to an increase in construction period and cost. There is a fear.

  Further, a sealing material 32 is interposed between the housing side flange 11 and the coupler 3, and a sealing material 34 is interposed between the housing side flange 11 and the seating surface of the temporary bolt 33. After the fixing reinforcing bar 4 is mounted, the sealing material 42 is interposed between the housing-side flange 11 and the water stop nut 41, so that leakage from the reinforcing bar insertion hole 1a can be prevented.

  In the present embodiment, the case where the columnar continuous underground wall is the mountain retaining wall W and the RC frame S is connected to the core material 1 of the columnar continuous underground wall is exemplified. It is not intended to limit the structure. Although not shown in the drawings, a constant thickness soil cement continuous underground wall formed by building a plurality of core materials in a continuous excavation groove may be used as a mountain retaining wall, or a plurality of steel core materials may be connected. The steel underground continuous wall to be formed may be a mountain retaining wall, and the RC housing may be connected to the steel core of the steel underground continuous wall.

  In this embodiment, the case where the core reinforcing bar 2 and the fixing reinforcing bar 4 are screw joint reinforcing bars is illustrated, but the type of reinforcing bars is not limited. Although not shown in the figure, the end of the deformed bar or steel bar is processed with a male thread, or the end of the deformed bar or the bar is pressed with a male screw part as the core rebar or anchoring bar. Also good.

  In the present embodiment, the case where the reinforcing bar 4 is a reinforcing bar different from the main bar, but the main bar itself may be the fixing bar.

  In the present embodiment, the case where the mechanical joint is a threaded joint is illustrated, but the type of the mechanical joint is not limited. For example, when the reinforcing bar for core material and the reinforcing bar for fixing are deformed reinforcing bars, although not shown, a mortar-filled joint that fills non-shrink mortar between the coupler (sleeve) and the reinforcing bar may be adopted. Good. A steel pipe crimp joint that crimps the coupler to the core rebar can also be employed on the core rebar side.

W Yamato wall 1 Core material 11 Frame side flange 1a Reinforcing bar insertion hole 12 Natural mountain side flange 2 Core material rebar 3 Coupler 31 Lock nut 32 Seal material 33 Temporary bolt S RC frame 4 Fixing rebar 41 Water stop nut 42 Seal material

Claims (4)

An underground structure formed by connecting an RC frame to the core of the mountain wall,
The core material is attached to a frame side flange having a reinforcing bar insertion hole, a ground mountain side flange facing the frame side flange, a core material reinforcing bar fixed to the ground mountain side flange, and the core material reinforcing bar. With a coupler for mechanical joints,
The coupler is disposed between the housing side flange and the natural ground side flange,
The RC housing includes a reinforcing bar that reaches the core material,
The underground structure according to claim 1, wherein the fixing rebar is connected to the coupler through the rebar insertion hole.   The underground structure according to claim 1, wherein a sealing material is interposed between the coupler and the housing-side flange. The coupler is formed with a female thread,
The fixing rebar is formed with a male screw that is screwed into the female screw,
A water-stop nut is screwed onto the male screw on the RC housing side of the housing-side flange,
A sealing material is interposed between the water-stop nut and the housing-side flange, or spray water-proofing treatment is applied to the water-stop nut and the fixing reinforcing bar. The underground structure according to claim 1 or 2. A method for constructing an underground structure formed by connecting an RC frame to the core of a mountain wall,
A coupler for a mechanical joint is disposed between the frame-side flange and the ground-side flange of the core material, and a core-material reinforcing rod from the coupler to the ground-side flange is fixed to the ground-side flange,
The shaft portion of the temporary bolt is inserted into the reinforcing bar insertion hole formed in the housing side flange, the shaft portion is screwed into the coupler, and the core material is put into the ground in the state where the coupler is closed with the temporary bolt. Built,
After excavating the ground and exposing the frame side flange, instead of the temporary bolts, the fixing reinforcing bars reaching the RC frame are inserted into the reinforcing bar insertion holes and connected to the coupler, and then the RC frame A construction method of an underground structure characterized by placing concrete.

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