JP2011241608A - Construction method of basement in existing house - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for constructing a basement in an existing house inexpensively and efficiently.SOLUTION: Excavating means and surplus soil discharge means are provided in an existing house, existing base concrete is chipped and removed, a skeleton caisson with a leading blade is formed inside the existing house, and the undersurface inside the skeleton caisson is excavated so that the skeleton caisson with a leading blade is made to sink by its own weight to a predetermined place. A basement is constructed by leveling the bottom surface of the place after the caisson has sunk and forming a pressure-proof board concrete and bars in the upper part of the basement.

Description

The present invention relates to a method for constructing a basement constructed in an existing house, and further, a caisson (circumferential wall) is excavated from the ground surrounded by the basement caisson (peripheral wall) and is submerged under its own weight in the basement. It relates to the construction method of self-weight subsidence caisson.

Conventionally, there is a so-called submersible construction method for constructing an underground structure consisting of a basement, an underground water tank, etc. in the basement. The submersible construction method is a method in which the caisson (surrounding wall) for underground structures built on the ground is submerged in the underground. The construction method involves submerging the underground structure in water and the inside surrounded by the caisson for the underground structure (surrounding wall). There is a method in which the caisson (surrounding wall) for underground structures is gradually submerged to the underground by its own weight while excavating the ground. The latter method is performed by an open type of caisson housing structure (peripheral frame shape having no bottom on the inside) in which a leading blade is provided at the lower part.

Many open-type caissons are provided with a caisson (surrounding wall) for an underground structure, and then a so-called submersible construction method in which the caisson is sunk underground. For this reason, the basement of an underground structure is constructed after the caisson (surrounding wall) for underground structures is sunk in the basement. In the construction where an open caisson is submerged by the submerged method, the caisson is produced on the ground. There are various advantages such as the burden of work is greatly reduced, the period is shortened, and the cost is reduced.

For example, in Patent Document 1, “The construction method of an underground structure according to the present invention is to place concrete on a concrete formwork on the ground surface to construct a concrete peripheral wall, and then remove the concrete formwork from the concrete peripheral wall. The excavation of the ground in the inner space of the concrete peripheral wall causes the concrete peripheral wall to sink, and the concrete peripheral wall without the concrete formwork sinks, so that the concrete peripheral wall is easy to handle. "
JP 2001-323435 A

However, although the method of patent document 1 is effective in a small land area etc., it is a construction method outside. An object of the present invention is to provide a method for easily and inexpensively constructing a basement in an existing house by solving a problem when constructing a basement in an existing house that has been difficult in the past at low cost and easily.

In order to solve the above-mentioned problems, the present inventors have conducted intensive research and adopted the following method. In other words, when creating a basement in an existing house, a caisson that constitutes the outer wall of the basement is placed in the existing house, and the caisson is submerged to a predetermined installation depth by its own weight to construct the basement. When taking a construction method, it is performed from the following three steps.
The first step is A) Carrying a small excavator or excavator into the basement construction site in the existing house, that is, a mini excavator such as a mini-yumbo or excavator such as a scoop or a pickaxe for excavating the ground in the existing house Carry in.
B) Remove existing base concrete and remove existing base concrete in existing houses.
C) Leading blade installation, steel frame, formwork assembled concrete milk filling, that is, setting the leading blade in preparation for constructing self-weight sinking caisson, steel frame, mold assembling, filling concrete milk and leading blade Prepare for caisson wall formation.

The second step D) forms a caisson wall with a leading blade, that is, a caisson wall with a leading blade prepared in the first step D).
E) Installation of means for discharging residual soil and means for discharging residual soil when excavating the lower part from the inside of the caisson wall.
F) The caisson sinks to a predetermined position by excavation, that is, the caisson sinks through the leading blade by excavating with an excavator or a drilling tool. This subsidence is performed to a predetermined position. G) Bottom leveling, predetermined When the caisson sinks to the position, the land is leveled. H) Carry out the small excavator or excavator and carry out the excavator or excavator that has been excavated to sink the caisson.
In the third step, I) bottom concrete construction, the caisson is submerged to a predetermined position, and then concrete construction is performed on the bottom. C) When removing the existing base concrete, use the rebar that left over 40 times the diameter of the reinforcing bar to form the upper basement wall beam. In the first step C), remove the existing base concrete. Form the basement wall upper beam by using the rebar that left over 40 times the diameter of the rebar.

In the third step, a reinforced concrete basement wall upper beam is formed as necessary. At this time, at the time of removing the existing base concrete in the first step B), the existing rebar is left over 40 times the diameter of the rebar, and when the above-mentioned reinforced concrete basement wall upper beam is formed, it is left over 40 times the existing rebar diameter. By using reinforcing bars, it becomes a basement upper beam that is strongly joined to the base of the existing house.

The existing base concrete in the first step C) as necessary according to the state of the site may be preceded by excavating the ground with an area in the range of 40% to 150% of the basement area after removing the suspension. If it is 150% or more of the basement area, it is difficult to remove the existing foundation, and if it is 40% or less, the work range of the excavator is narrow, which causes inconvenience in excavation work. In some cases, a leading moat is not used, but a leading moat may be necessary to facilitate work depending on the construction conditions.

What is necessary is just to perform the depth in the case of performing a preceding moat in the range of 300-1000 mm according to the condition of a field. There is a case where the leading moat is not used, but there is a case where the leading moat is made to facilitate work depending on the construction conditions. Here, 300 mm is appropriate for the ground that is easily collapsed, and 1000 mm is appropriate for the ground that is not easily collapsed. Furthermore, the preceding moat is divided into a first stage and a second stage, and the first stage may be performed broader than the second stage, and a leading blade or the like may be installed in the portion of the first stage.

What is necessary is just to form this caisson wall outer peripheral part protective layer after caisson wall formation. The protective layer here may be sprayed or pasted with a waterproof layer or a styrene foam layer as required. F) The residual soil means may be installed as necessary by installing a belt conveyor.

The bottom leveling of H) may be crushed by a ramp or the like as necessary. In particular, if the ground surface is weak in ground strength, it is sufficient to arrange and roll chestnut stones. If necessary, the bottom surface excavated after the bottom surface preparation of H) may be disposed of, including the vicinity of the outer peripheral portion, if necessary. The floor surface may be waterproofed after the bottom surface preparation of H) or after the bottom surface concrete is cast.

In the second step, the aggregate of the outer peripheral part is raised as necessary, the aggregate is raised on the outer peripheral part of the caisson, and the wall surface and caisson of the ground that the outer peripheral part of the leading edge forms when the caisson sinks under its own weight Aggregate flows between the outer peripheries to reduce friction.

Third step I) Concrete construction on the bottom surface is reinforced concrete pressure board construction, that is, pressure board reinforced concrete construction is performed on the bottom. Also, if there is a floor surface in the basement grounding area in the existing house, this floor surface is removed in the first step.

According to the present invention, when a basement is created in an existing house, a caisson constituting the outer peripheral wall of the basement is placed in the existing house, and the caisson is submerged to a predetermined installation depth by its own weight by excavating the lower part inside the caisson. When building a basement, it becomes easy and inexpensive to build a basement in an existing house that could not be easily done before.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

Fig. 1 shows the flow when creating a basement in an existing house, Fig. 2 is a cross-sectional view of preparation for caisson construction for basement construction, and Fig. 3 explains the first floor part of the existing house and basement construction caisson. In the figure, FIG. 5 shows the first floor of an existing house and the basement constructed by the caisson method. The first step S11 is to remove the floor of the basement installation place in the existing house when there is a floor, and is shown by 3 in FIG. S12 is A) carrying an excavator such as a small yumbo or a drilling tool into a basement installation location in an existing house. S13 is B) Lifting of the existing base concrete, which is represented by 4 in FIG. Here, if necessary, leaving the reinforcing bars in the existing base concrete at least 40 times the diameter of the reinforcing bars is advantageous in terms of strength for the upper basement beam later, as shown in FIG. S14 is an emperor who prepares a caisson by assembling a leading blade, a steel frame, and a formwork and filling concrete milk with S14. 2 in FIG. 2 indicates a leading blade.

Here, a prior digging may be carried out depending on the situation at the site, but in this embodiment, a case of a two-stage digging is shown. 2 in FIG. 2 is the first stage leading excavation, and it is only necessary to assemble a steel frame and formwork by installing one leading blade in this portion. Reference numeral 7 in FIG. 2 is the second stage leading excavation, and it is only necessary to excavate by installing an excavating machine such as a small yumbo or an excavating tool carried there. Needless to say, an excavator such as a small Yumbo or an excavating tool may be used for the preceding excavation.

Next, the second step will be described. S21 is D) formation of a caisson wall with a leading blade, and the concrete milk prepared in the first step S14 is solidified to form a caisson wall. This is indicated by 10 in FIG. Here, a caisson wall outer peripheral protective layer for the purpose of waterproofing or the like may be provided as necessary, and this state is shown in 11 of FIG. S22 may be provided with the waste soil removal means of E). The excavator or excavator such as a small Yumbo is used for excavation, but the remaining soil comes out here. Although it is necessary to discharge this outside, a belt conveyor may be installed to discharge the remaining soil. This is shown in FIG.

S23: F) The caisson with a leading blade is sunk to a predetermined position by excavation. This state is shown in FIG. S24 is G) Landslide leveling. Reference numeral 15 in FIG. 5 denotes the land, and rolling may be performed by spreading a chestnut or the like as needed and using a ramma or the like. After that, it is effective if a concrete construction is carried out at a portion 13 in FIG. 5 and waterproofed with an envi sheet as indicated by 14 in FIG. S25 is H) Since excavation has been completed, an excavator such as a small yumbo or an excavating tool is no longer necessary, and it may be carried out.

Next, the third step will be described. S31 is I) bottom concrete construction. Here, reinforced concrete pressure board construction is performed. At the same time, the basement upper beam may be constructed. If the basement upper beam is constructed by using the part of the above-mentioned existing base concrete where the rebar is left at least 40 times the diameter of the reinforcing bar, Bonding strength is increased and the strength of the house is increased.

Next, since the caisson smoothly settles due to excavation in the second step, when aggregate (sand, etc.) is raised on the outer periphery of the caisson, the friction is reduced and the purpose is achieved, as shown in FIG. FIG. 6 shows the state of the sinking, and the leading blade at position 17 sinks to position 1. Here, 2 is the ground, 10 is the caisson wall, 11 is the caisson outer periphery protective layer, 19 is the excavation surface by the outermost periphery of the leading blade, and 20 is the aggregate layer. The presence of these 20 aggregate layers reduces friction and allows the caisson to settle down by its own weight. Reference numeral 21 denotes a vertical line passing through the outermost peripheral portion of the leading blade. The leading blade which was at position 22 represents the movement of sinking to the position of 1 by 23, and a new aggregate as indicated by 24 between the excavation surface formed by the leading edge outer periphery and the caisson outer periphery protective layer by the sinking. Even if it flows in and sinks, the friction is not particularly increased, and the caisson with the leading blade smoothly sinks by its own weight.

Flow when creating a basement in an existing house Cross section of preparation of caisson construction for basement construction 1st floor part of existing house and caisson for basement construction Belt conveyor installation Basement constructed with the first floor of the existing house and the caisson method Effect of raising aggregate (sand, etc.) on caisson outer periphery

S11 Existing house basement installation floor floor removal S12 Small excavator and excavation tool into existing house S13 Existing base concrete suspension removal S14 Lead blade, steel frame, formwork assembly concrete milk filling S21 Caisson wall with lead blade Formation S22 Waste soil removal means installation S23 Sedimentation down to caisson predetermined position by excavation S24 Soil leveling S25 Small excavator, excavation tool removal S31 Bottom concrete construction 1 Leading edge
2 ground
3 When the floor is removed
4 Existing base concrete is hanging 5 Existing rebar is left (length 40 times longer than rebar diameter)
6 Leading moat (1) First stage 7 Leading moat (2) Second stage 8 Existing base concrete remaining part 9 Existing housing wall 10 Caisson wall
11 Caisson wall outer peripheral protective layer 12 Belt conveyor 13 Abandoned concrete
14 Waterproof treatment (enbi sheet)
15 Bottom surface Place Kuriishi etc. if necessary
16 Reinforced concrete pressure board
17 Basement Upper Beam 18 Basement Upper Beam Reinforcement 19 Utilizing Existing Reinforcement 19 Drilling Surface 20 Aggregate (Sand, etc.)
21 Vertical line passing through the outermost periphery of the leading blade
22 Position before the settling of the leading blade 23 Movement of caisson and leading blade
24 Aggregate movement

Claims (13)

When creating a basement in an existing house, a caisson that constitutes the outer wall of the basement is placed in the existing house, and the lower part of the caisson is excavated to sink the caisson to a predetermined installation depth by its own weight. 1) A) A small excavator or excavator is brought into the basement construction site in the existing house B) The existing base concrete is lifted C) The leading blade is installed, Second step composed of steel frame, formwork assembled concrete milk filling D) to H) D) Formation of caisson wall with leading blade E) Installation of waste soil removal means F) Excavation of self-weight to caisson predetermined position by excavation G) Bottom surface Leveling H) Third step consisting of small excavator or excavation tool I) I) Method of constructing underground house in existing house consisting of three steps of concrete construction on the bottom The method for constructing a basement in an existing house according to claim 1, wherein an upper beam of a reinforced concrete basement wall is formed in the third step. When removing the existing base concrete in step B) of the second step, the existing rebar is left over 40 times the diameter of the rebar, and the rebar left over 40 times the diameter of the existing rebar is used when forming the upper beam of the reinforced concrete basement wall. A method for constructing a basement in an existing house according to claim 2, characterized in that: According to the condition of the site, after removing the suspension of C), the ground is subjected to a 300-1000 mm depth moat with an area in the range of 40% to 150% from the basement area. Thru 3 existing basement construction method The method for constructing a basement in an existing house according to claims 1 to 4, wherein the preceding moat has two stages. 6. The method for constructing a basement in an existing house according to claim 1, wherein the caisson wall outer periphery protective layer is formed after the caisson wall is formed. The method for constructing a basement in an existing house according to any one of claims 1 to 65, wherein the waste soil disposal means is a belt conveyor. The method for constructing a basement in an existing house according to claims 1 to 7, wherein the land leveling is a land rolling pressure. 9. A method for constructing a basement in an existing house according to claims 1 to 8, wherein the concrete is disposed in the vicinity of the outer periphery and the bottom. 10. A method for constructing a basement in an existing house according to claims 1 to 9, wherein the floor is waterproofed after bottoming or after bottom concrete is cast. The method for constructing a basement in an existing house according to any one of claims 1 to 10, wherein the aggregate is raised on the outer periphery of the caisson as necessary in the second step. The method for constructing a basement in an existing house according to claims 1 to 11, characterized in that the concrete construction on the bottom of the third step I) is a reinforced concrete pressure panel construction. The method for constructing a basement in an existing house according to claims 1 to 12, wherein the floor surface is first removed in the first step when the floor surface exists.

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