KR20200122850A - Construction method for building concrete foundation which piles are supposed to be exposed because of nearby excavation - Google Patents

Abstract

The present invention relates to a construction method of a basis of a building. When piles on a lower side of a basic concrete structure are exposed when an excavation construction is conducted on adjacent ground after a basic concrete structure is built, there are problems such as security of safety of upper framework in accordance with a reduced basic pile strength and possibility of generation of displacement on a slope. The present invention can solve the problem by identifying the areas where an excavation on a lower side of the basic concrete structure is expected in advance, connecting the basic concrete structure to other basic concrete structures by a connection beam when constructing the basic concrete structure placed in the area, and designing basic piles through an analysis for each step of construction and taking an action to stabilize the slope. Accordingly, after the excavation on the slope, an upper framework construction can be simultaneously conducted also for the area with the basic piles exposed regardless of the refilling work such that the construction period and the cost can be reduced.

Description

Construction method for building concrete foundation which piles are supposed to be exposed because of nearby excavation}

The present invention relates to a basic construction method of a building. When the ground height of the foundation of a building is different for each zone and a step occurs between adjacent foundation structures, the piles under the previously constructed foundation structure may inevitably be exposed due to excavation work on the adjacent ground. In this situation, it relates to a construction method of reinforcing a foundation structure so as to solve the problems of the conventional construction method, and to proceed with the frame construction of the upper part of the foundation with the pile exposed.

In general building construction, basic structure construction to support the columns and walls of the building, to prevent the building from cracking or tilting due to the torsion stress of the column and wall, and to evenly distribute the load of the building to the ground. Do it. The foundation work of a building is the construction of the lowest floor area that directly receives the load of the building, and the foundation structure is constructed under the lowest floor, mainly composed of a combination of piles and concrete structures.

The pile can be said to be a concrete column penetrating the ground, and it serves to transmit the load of the above-ground structure to the ground, and the penetration depth is determined by designing according to the nature of the ground and the type of pile.

Conventionally, in general, a pile is constructed in the ground to prevent ground subsidence due to a building load and to create a solid ground, and a foundation concrete structure connected to the pile is constructed on the top of the constructed pile. After such a foundation work is completed, the frame work that forms the frame of the building is carried out on the upper part of the base concrete structure. At this time, the base concrete structure must be seated on the ground because the load of the upper frame must be stably transmitted to the ground.

On the other hand, when the basement layer of a building has a different depth for each area on the plane, the level difference may occur due to the different ground heights of the foundation concrete structures adjacent to each other. At this time, when the ground is excavated for the construction of a foundation concrete structure with a lower ground height, the deeper the excavation is, the wider the slope is formed, resulting in a situation in which the soil under the previously constructed adjacent foundation concrete structure is inevitably excavated.

In such a situation, the top of the pile under the adjacent foundation concrete structure is exposed to the ground, and at this time, problems such as reducing the strength of the exposed pile and securing the stability of the upper frame according to the possibility of displacement of the excavation slope occur. It is not stable enough to proceed with the upper frame construction.

1 (a) to (g) shows a conventional general construction procedure in the above-described situation.

Referring to (d) of FIG. 1, the foundation concrete structure 130 corresponds to a state in which the foundation pile 121 of the lower part is exposed to the ground, so that the upper frame construction is impossible. Therefore, the conventional construction method constructs the concrete wall 140 at the lower end of the excavation slope as shown in FIG. 1(e), and backfills the lower part of the foundation concrete structure 130 with soil as shown in FIG. 1(f) (150) And, only after that it was possible to proceed with the upper frame construction 160 as shown in Figure 1 (g).

However, as the size of the concrete wall increases, reinforcement assembly and concrete pouring and curing are repeated several times, and the soil cannot be backfilled until the concrete wall has secured considerable strength. There is a problem of delay.

Registered Patent No. 10-1105883 (announcement date: 2012.01.16.) Registration Patent No. 10-1220811 (announcement date: 2013.01.11.) Publication Patent No. 10-2014-0067312 (Publication date: 2014.06.05.)

The present invention is to improve the problems of the prior art, even if there is a foundation concrete structure in which the foundation pile is exposed due to a step difference between adjacent foundation concrete structures having different ground heights during the foundation construction process of a building, Its purpose is to provide a method of improving the construction method of the foundation construction so that the upper frame construction can be carried out.

The foundation construction method according to the present invention for achieving this object includes: (a) a first step of setting an area in which the foundation pile of the foundation concrete structure is expected to be exposed by earth and sand excavation under the foundation concrete structure; (b) a second step of constructing a foundation pile located in the first step setting area; (c) a third step of constructing a foundation concrete structure connected to the top of the foundation pile constructed in the second step; (d) a fourth step of connecting the base concrete structure located in the first step setting area to another adjacent base concrete structure with a connecting beam; (e) a fifth step in which at least a part of the foundation pile of the foundation concrete structure is exposed to the ground by excavating the soil in the first stage setting area after the concrete strength of the foundation concrete structure formed in the third stage is secured; (f) a sixth step of proceeding the upper frame construction of the fifth step of the basic concrete structure, wherein the basic concrete structure is characterized in that the joint is embedded in order to connect with the connecting beam.

Preferably, a real-time monitoring system is constructed by installing a displacement measuring system and a stress measuring system on the foundation concrete structure in which the foundation pile is exposed between the fifth and sixth stages, and the foundation pile and the connecting beam.

Through this, after the excavation of the slope, regardless of the backfilling operation, the upper frame construction can be simultaneously performed on the area where the foundation pile is exposed, thereby reducing construction time and cost.

According to the method for foundation construction of a building according to the present invention, even if a situation in which the foundation piles of some basic concrete structures are unavoidably exposed according to the construction order of the foundation of the building, the construction period can proceed immediately from the upper part regardless of the concrete wall construction. Can shorten and reduce costs.

(A) to (g) of Figure 1 is a view briefly showing the construction procedure of a conventional general foundation work.
Figure 2 (a) to (f) is a view briefly showing the construction procedure of the foundation according to an embodiment of the present invention.
3 is a conceptual diagram of a slope reinforcement method according to an embodiment of the present invention.
4 is a conceptual diagram of a monitoring system according to an embodiment of the present invention.
5 is a conceptual diagram illustrating a connection part between a basic concrete structure and a connecting beam according to an embodiment of the present invention.

Embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described in the present specification, and should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to the other component, but other components may exist in the middle. something to do. On the other hand, when a component is referred to as being "directly connected" or "directly in contact" with another component, it should be understood that there is no other component in the middle. Other expressions for describing the relationship between components, that is, expressions such as "between" and "directly between" or "adjacent to" and "directly adjacent to" should be interpreted as well.

The terms and expressions in the drawings used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

Hereinafter, a method of constructing a foundation for a building according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2A to 2F are diagrams briefly showing the construction procedure of a foundation work according to an embodiment of the present invention.

As illustrated in FIG. 2, in the construction method of the foundation of the building of the present invention, in the foundation construction of a building in an area where the foundation pile is expected to be exposed due to excavation of the ground under the foundation concrete structure, (a) the soil under the foundation concrete structure A first step of setting an area in which the foundation pile of the foundation concrete structure is expected to be exposed by excavation; (b) a second step of constructing a foundation pile located in the first step setting area; (c) a third step of constructing a foundation concrete structure connected to the top of the foundation pile constructed in the second step; (d) a fourth step of connecting the base concrete structure located in the first step setting area to another adjacent base concrete structure with a connecting beam; (e) a fifth step in which at least a part of the foundation pile under the foundation concrete structure is exposed to the ground by excavating the soil in the first stage setting area after the concrete strength of the foundation concrete structure formed in the third stage is secured; And (f) a sixth step of proceeding the upper frame construction of the basic concrete structure of the fifth step; including, and the basic concrete structure is characterized in that the joint is embedded before concrete pouring to connect with the connecting beam.

Hereinafter, each process will be described in detail.

Referring to Figure 2 (a), the first step is a step of establishing the most efficient construction sequence and excavation plan according to the foundation design of the building before starting the on-site construction. In the case of a large-area foundation work, be careful not to interfere between processes because the excavation of soil and the construction of the structure are performed simultaneously.

In this planning process, it is possible to identify the area where the level difference occurs on the ground due to the difference in the excavation depth, and after the construction of the foundation concrete structure 30 is completed in the process, excavation of the lower soil is performed, and the foundation pile 21 under the foundation concrete structure is completed. ) Can be expected. That is, in the process of establishing an excavation plan, it is possible to identify the planned excavation surface 11 and set the area in which the foundation pile 21 under the foundation concrete structure is scheduled to be exposed on the floor plan of the site.

2(b), the second step is a step of constructing the foundation pile 20 on the ground. The number of foundation piles and construction depth are calculated to obtain sufficient support according to the design load of the building. There are various types of foundation piles and construction methods, and the person in charge will make the optimal selection by reflecting the site conditions and design review contents from the viewpoint of minimizing cost and construction time.

In general, there are two types of pile construction: a method of curing after pouring concrete at the site (laying on site piles) and a method of driving or drilling ready-made PHC piles (Pretensioned spun High strength Concrete Piles) to penetrate the ground. In this embodiment, it is possible to construct any type of foundation pile according to the design.

In the case of piles that are expected to be exposed due to future excavation work, the stronger the bending moment strength of the pile is, the better, and it is preferable to use a PHC pile with an effective prestress of 80 kg/㎠ (Class B) or more. In addition, in the case of the foundation pile 21 under the foundation concrete structure, it is preferable to design it to be near the bottom of the slope by 10m or more even after excavation.

Referring to (c) of FIG. 2, the third step is a step of constructing the foundation concrete structure 30 after the foundation pile 20 is constructed. This is a method of arranging the head of a pile by constructing a concrete structure according to a conventional method, reinforcing the reinforcing bars of the foundation concrete structure 30, installing a formwork, and pouring concrete. In this case, in consideration of the fourth step of connecting the connecting beam 40 in FIG. 2(d), the joint 42 is pre-embedded in the portion connected to the connecting beam 40 and then concrete is poured.

5, a joint 42 embedded in the basic concrete structure 30 according to an embodiment of the present invention is shown. The joint 42 embedded in the basic concrete structure 30 may use an H beam. After fastening the stud bolt to the flange of one end of the H beam, it is embedded in the basic concrete structure 30, and the other end of the H beam is exposed to the outside of the basic concrete structure. The exposed part corresponds to a part connected to the connecting beam 40. The length at which the joint 42 is embedded in the basic concrete structure 30 may be determined by examining the structural design.

Referring to (d) of FIG. 2, the fourth step is to connect the basic concrete structure 30 located in the setting area 13 after the construction of the basic concrete structure 30 to the adjacent other basic concrete structure 31 This is the step of connecting using (40).

Since construction on the site is performed simultaneously in several areas, construction of other basic concrete structures (31) or foundation mat concrete structures (32) that are independent in accordance with the design content in addition to the foundation structures located in the set area (13) is in progress. do.

The other foundation concrete structure 31 above may be a mat type or independent type foundation structure that is not located in the setting area 13, and is a foundation concrete structure in a state where the foundation pile located in the setting area 13 is exposed. May be.

The length, cross-sectional shape, buckling coefficient, etc. of the connecting beam 40 and the number of connecting beams 40 may be determined through site conditions and design review. As an example, the connecting beam 40 may use an H-beam, and FIG. 5 shows the connecting portion 43 to which the connecting beam 40 and the joint 42 are fastened.

According to an embodiment of the present invention, the joint 42 and the connecting beam 40 embedded in the basic concrete structure 30 are connected by welding or bolts, or in various ways to efficiently transmit the applied stress. It will be possible.

Referring to (e) of Figure 2, the fifth step is a step of excavating an area to be excavated when the concrete strength of the basic concrete structure 30 is expressed after the connection of the connecting beam 40 is completed. When the strength of concrete is secured, deformation of the structure can be minimized even after excavation, and the required strength can be determined by judgment or design review by the person in charge of the site.

In this step, since the soil under the foundation concrete structure 30 is excavated, the foundation pile 21 under the foundation concrete structure is exposed to the outside.

On the other hand, for the slope 14 formed by excavation, it is preferable to review the slope stability analysis in consideration of the previously constructed foundation pile 20 and the penetration of groundwater, and the stability of the previously constructed foundation pile 20 should also be reviewed. I can. Even before excavation, the slope of the stable slope 14 and the number of benches can be planned through slope stability analysis.

Since the formed slope 14 must be maintained in a stable state until the excavation space is refilled, slope stabilization is required.For example, as shown in Fig. 3, a tarpaulin 16 is installed on the entire slope to block external disturbances. It is possible to install a tone bag 15 to prevent loss of the lower part of the slope. In addition, various construction methods for slope stabilization purposes can be used.

Referring to (f) of Figure 2, the sixth step is a step in which the frame work is performed on the top of the foundation structure in a state where the foundation pile is exposed. In this case, there is a possibility that the structure may be deformed due to external force caused by the load on the frame. Therefore, in order to ensure the safety of the structure, it is desirable to construct a system capable of measuring deformation due to external force in real time.

Referring to FIG. 4, there is shown an installation of a measuring instrument according to an embodiment of the present invention. Measurement should be made until the excavated space under the foundation concrete structure 30 is backfilled. It is necessary to measure the lateral displacement of the foundation concrete structure 30 and the foundation pile 21 under the foundation concrete structure, and a target on the side of the foundation concrete structure 30 and the foundation pile 21 under the foundation concrete structure ( 33) is installed, and it is desirable to measure at least twice a week on a regular basis.

EL. To measure the transverse deformation of the foundation pile (21) under the foundation concrete structure. A beam 22 can be used, and in the case of the connecting beam 40, a stress meter 41 is installed to periodically measure the stress received from the connecting beam 40. Allowable displacement and stress values can be determined through design review, and if displacement or stress exceeds the allowable values, the construction of the upper frame 60 should be stopped and safety should be secured through a series of reinforcement works. As a reinforcement method, a method of adding the number of connecting beams 40 or filling a part of the excavation area may be considered.

When implementing the construction method according to the embodiment of the present invention, the design load according to the ground floor construction will be considered, and accordingly, the maximum exposure length of the foundation pile 20 can be calculated.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings. In addition, it will be apparent to those of ordinary skill in the art that the present invention can be substituted, modified, and changed in various forms without departing from the technical spirit of the present invention.

10: ground
11: To be excavated
12: Excavation surface
13: Setting area
14: Slope
15: Tone bag
16: waterproof cloth
20: Basic file
21: Foundation pile under the basic concrete structure
22:El. Beam
30: Basic concrete structure
31: other foundation concrete structures
32: foundation mat concrete structure
33: target
40: connecting beam
41: stress meter
42: joint
43: connection
50: Slope lower part structure construction
60: frame
110: ground
111: The surface to be excavated
112: Excavation surface
120: basic file
121: foundation pile under the basic concrete structure
130: basic concrete structure
131: other foundation concrete structures
132: Foundation mat concrete structure
140: concrete wall
150: backfill
160: frame
170: Construction of structures in other areas

Claims (4)

In the building foundation work in the area where the foundation pile is expected to be exposed due to excavation of the ground under the foundation concrete structure,
(a) a first step of setting an area in which the foundation pile of the foundation concrete structure is expected to be exposed through earth and sand excavation under the foundation concrete structure;
(b) a second step of constructing a foundation pile located in the first step setting area;
(c) a third step of constructing a foundation concrete structure connected to the top of the foundation pile constructed in the second step;
(d) a fourth step of connecting the base concrete structure located in the first step setting area to another adjacent base concrete structure with a connecting beam;
(e) a fifth step in which at least a part of the lower foundation pile of the foundation concrete structure is exposed to the ground by excavating the soil in the first stage setting area after the concrete strength of the foundation concrete structure formed in the third stage is secured; And
(f) a sixth step of proceeding the upper frame construction of the foundation concrete structure of the fifth step; includes,
The construction method of the foundation of a building, characterized in that the joint is embedded before concrete pouring in the foundation concrete structure to connect with the connecting beam. The method of claim 1,
In the second step, the PHC pile among the foundation piles is a construction method of the foundation of a building including a PHC pile with an effective prestress of 80kg/㎠ or more. The method of claim 1,
The construction method of the foundation of a building, including the step of stabilizing the slope of the slope of the fifth step and then installing a tarpaulin in all areas of the slope formed by excavation and installing a tone bag at the bottom of the slope. The method of claim 1,
In step 5, installing a foundation concrete structure in which at least a part of the foundation pile is exposed and a measuring system for measuring the displacement of the exposed foundation pile, and installing a stress measurement system on the connecting beam in the fourth step to establish a real-time monitoring system Construction method of a building foundation comprising a.

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