JPS621930A - Foundation structure of underground structure - Google Patents

Abstract

PURPOSE:To raise the close contactness of the joints of slabs by a method in which an excavating blade is provided to the tip of a formwork of a V-shaped cross section, one ends of the steel bars of a welded metal net are directed upwards along the inner surface of the formwork, and the inner surface of the formwork is covered with an elastic sheet. CONSTITUTION:On the land, a formwork of a V-shaped cross section is formed of an excavating blade 1 and molds 2 and 2', and a welded metal net 4 and steel bars 5 are inserted into the formwork. One ends of the net 4 and the bars 5 are directed upwards along the inner surface of the mold 2', and the inner surface of the mold 2' is covered with a slightly loosened elastic sheet 6. Concrete is then placed into the formwork of the V-shaped cross section and hardened, the molds 2 and 2' are removed, and the body is settled into the hole excavated by the blade 1 in the ground. One ends of the net 4 and the bars 5 are extended, the sheet 6 is removed, and slab concrete is placed. The close contactness between the wall body and the slab can thus be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to at least a reinforced concrete frame of an underground building and a structure necessary for a foundation portion to be submerged and buried.

Conventional reinforced concrete foundations for underground buildings tend to have poor adhesion between the foundation and underground slab joints, and tend to lack the number of reinforcing bars and the length of anchorage and lap joints at the joints. It was easy for water to leak due to peeling and cracking, and the formwork was severely damaged, which could not be avoided.

This invention was made with the aim of improving the above-mentioned drawbacks of the foundations of conventionally known underground structures.

The structure of the foundation of the underground building of this invention has a V-shaped cross section, has a digging blade at the tip, a plurality of reinforcing steel members attached to the inclined formwork surface, and an elastic sheet. The materials and shapes used in this invention include JIS standard products such as welded wire mesh, deformed steel bars, and round bars for steel materials for differential reinforcement, and JIS standard products for drilling blade materials such as welded wire mesh, deformed steel bars, and round steel bars. , angle iron is preferred, but angle iron for drilling may be superimposed on angle iron, or CT type steel may also be used.For small-scale buildings, the tip of the V-shaped cross section may be reinforced with steel bars, etc. It may be something that has been done. The elastic sheet is preferably an elastic plastic-based film, such as an elastic polyurethane film, and is preferably an elastic strip-like sheet made of closed-cell foamed plastic. An asphalt-based nonwoven fabric may also be used.

The structure of the foundation of the underground structure of this invention will be explained in detail based on the drawings. First, a removable excavation blade (1 )
are assembled and installed horizontally, and based on the excavation blade material (1), the outer surface of the formwork (2) is slightly inclined inward,
As shown in Figure 1, the inner surface is formed into a V-shape by inclining the formwork (2') at 30° to 45° from the inner end of the excavating blade material (1) and making the upper end protrude from the inner wall surface of the frame. Base part of the cross section (3
), and the sloped surface on the inner periphery is used as the bonding part for the steel materials (4) and (5) for the differential reinforcement, and it becomes the joint part of the slab concrete, and for the installation of the differential reinforcement,
In the cross section of the foundation (3), the welded wire mesh (4) is bent while maintaining the specified fixed length, inserted into the V-shaped cross section, and the lap joint at the other end is formed into an inclined formwork (2'). It is glued to the surface and uniformly attached to the inner circumferential surface of the formwork (2') to form a lap joint for the lower end reinforcement, and is mainly made of deformed steel bar ( 5), a spring stacked together at a specified interval, and the welded wire mesh (
4) From the lower end of the bonded part upwards, overlap the existing bonded part at a prescribed interval, and as above, put the lower part in the V-shaped cross section and make each of the upper parts protrude upward. In order to install the elastic sheet (6), at least the formwork (2') of the reinforcing steel materials (4) and (5) is required.
Start covering the wire mesh (4) attached to the lower tier with the glued part and a plurality of band-shaped elastic sheets (6), leave some slack, fix each corner to the formwork (2'), and then cover the upper tier one by one. The sheet (6) is also fastened in the same manner to prevent the fresh concrete from adhering or sinking, and the sheet (6) can be freely expanded due to the pouring pressure, and the sheet (6) can be fastened to the reinforcement steel (4) (5) and the formwork ( 2')
The surface is brought into contact with the surface to form a mesh-like uneven surface (7).
In parallel with the assembly of the wall reinforcement (8), the formwork for the inner wall (2) is assembled vertically, and the formwork for the outer wall (2) is installed with a slight inward slope. The outer shell frame is constructed by gradually increasing the wall thickness at the lower part than at the upper part, and by providing a beam shape (9) projecting laterally at the top of the wall.

Next, the foundation part (3) and the frame forming the outer shell are poured simultaneously using ready-mixed concrete, and after the prescribed curing period has elapsed, the formwork (2) and (2') are gradually discarded. , apply a permeable crystalline waterproofing agent to at least the outer circumferential surface of the structure, and use the caisson construction method to crush and cut the ground with the action of the excavation blade (1) attached to the foundation (3) of the structure. The structure is gradually settled horizontally, and when the subsidence of the structure reaches a specified depth, it is supported by a horizontal subsidence prevention shoring installed at the lower end of the beam type (9) at the top of the structure. Although the subsidence of the building frame was stopped, in order to correct it horizontally through accurate erection, shoring was added to stop the structure, and the outer periphery was filled with earth and sand to completely prevent the structure from subsidence.

As shown in Figure 2, for solid foundation work, horizontal and flat excavation is carried out to provide a wide space on the inner peripheral surface including the lower part of the foundation (3), and the excavation blade is removed from the foundation (3). Material (
1) was gradually cleared and compacted with crushed gravel and a deep space was created at the lower end and inner periphery of the foundation (3). Apply sufficient reinforcement (8), tie the bottom end of the double reinforcement for slab (8) to the reinforcement (8) above, bend the welded wire mesh (4) to the specified position, This joint part is connected to the end of the lower end reinforcement, the elastic sheet (6) is peeled off and the uneven rough surface (7) is exposed, and the same operation is performed for the upper end reinforcement, using a normal construction method. A steel bar made into a lap joint (
Each of 5) is combined with reinforcing bars for the slab and upper end bars to assemble the reinforcement, and furthermore, the elastic sheet (6)
was removed, and an uneven rough surface suitable for concrete joints (7
).

In addition, when pouring slab concrete, the concrete is placed at the joint section which has a rough surface along with the lower space of the foundation (3), at the thick walled section to cover it, and at the inner circumferential surface of the structure. After concrete pouring, vibrators and tamping were applied to ensure that the joints and reinforcing bars were in close contact with each other without any gaps, the slab surface was leveled and a flat sub-floor surface was created, and the foundation was built integrally with the frame. be.

Since the present invention is configured as described above, it is possible to install relatively long overlap joints of the steel materials (4) and (5) for differential reinforcement by using the inclined formwork (2'), and the joint part can be By increasing the rigidity and making it easier to assemble and dismantle without damaging the formwork (2'), the outer peripheral surfaces of the foundation (3) and walls are slightly sloped to prevent the frame from sinking. It is designed to soften the earth pressure resistance in contact with the outer circumferential surface of the structure, making it easier to sink, and by attaching the tip of the foundation (3) and the excavation blade (1), it is possible to safely and gradually sink without impacting the structure. At the same time, since the earth and sand around the outer periphery of the building frame are not disturbed, the area where the external ground will not settle is extremely narrow, making it possible to install it close to existing buildings. (3) The permeable crystalline waterproofing layer (10) applied to the outer surface seals and waterproofs minute gaps in the concrete and crystallizes it, prevents deterioration of concrete and reinforcing bars, and reduces humidity content. This prevents the growth of mold, and by adding the uneven rough surface (7), it provides a wide joint in the concrete.
It improves adhesion with the underground slab, prevents cracks and water leakage, and creates a solid foundation that is integrated with the frame, making it possible to create a highly rigid underground structure.

[Brief explanation of drawings]

Figure 1 shows the basic part (3) of this invention and on the ground.
Assemble the formwork (2) (2') based on the excavation blade material (1), install the steel materials (4) and (5) for the differential reinforcing bars and the elastic sheet (6),
It is a partial sectional view with a part of reinforcement (8) omitted. Figure 2 shows that the reinforced concrete frame of this invention is buried underground, and by pouring underground slab concrete,
It is a cross-sectional view showing a solid foundation integrated with the frame, with a part of the frame cut away, and a part of the reinforcement (8) omitted. 1 is the excavation blade material, 2 is the formwork, 2' is the inclined formwork, 3 is the foundation, 4 is the welded wire mesh for the differential reinforcement, 5 is the steel bar for the differential reinforcement, 6 is the elastic sheet, 7 is the uneven surface or uneven shape Rough surface, 8 is reinforcement, 9 is beam type, 10 is permeable crystal waterproof layer.

Claims (1)

[Scope of Claims] 1. In a V-shaped cross section, a cutting blade material is provided at the tip, a plurality of reinforcing steel materials etc. are attached to the inclined formwork surface, and are covered with an elastic sheet, The structure of the foundation of an underground building. 2. The structure of the foundation of an underground building according to claim 1, wherein the excavation blade material is made of overlapping angle iron. 3. The structure of the foundation of an underground building according to claims 1 and 2, wherein the steel material for the differential reinforcement is a welded wire mesh. 4. The structure of the foundation of an underground building according to claims 1 to 3, wherein the elastic sheet is an elastic plastic film. 5. The structure of the foundation of an underground building according to claim 4, wherein the elastic sheet is a film of elastic synthetic plastics. 6. The structure of the foundation of an underground building according to claims 4 to 5, wherein the elastic sheet is a band of closed-cell elastic foam plastic. 7. The structure of the foundation of an underground building according to claims 4 to 6, wherein the elastic sheet is an elastic asphalt-based nonwoven fabric.