KR102296811B1 - Foundation construction method for inducing Pseudo-layered soils - Google Patents

Abstract

Disclosed is a foundation construction method for inducing pseudo-layered soils. In accordance with an embodiment of the present invention, a foundation construction method for inducing pseudo-layered soils comprises the steps of: arranging an upper part of the soft ground to be reinforced; placing crushed stone or crushed stone mixed with sandy soil on the arranged soft ground to form a hard layer of a thickness, thereby forming pseudo-layered soils; installing a bearing plate mold, in which a plurality of cylindrical bearing protrusions having flat bottom surfaces, having open upper ends, and having hollow parts of a height are distributed, so that the cylindrical bearing protrusions face the hard layer; and forming a bearing concrete foundation plate by pouring and curing concrete on an upper part of the bearing plate mold so that bearing piles are formed by filling the hollow parts of the cylindrical bearing protrusions with concrete. Therefore, bearing power can be ensured.

Description

Foundation construction method for inducing Pseudo-layered soils

The present invention relates to a similar stratified ground induction foundation method. In more detail, a similar layered ground is induced by forming an artificially hard layer on the soft ground to be reinforced, and the support force can be secured by forming an acupressure concrete base plate on which a small column-shaped acupressure pile is distributed. It relates to the stratified ground induction foundation method.

When constructing a structure such as a building on the ground, the foundation is formed to stably transfer the weight of the structure and the load applied to the structure to the ground, and to prevent disturbances such as subsidence, inclination, movement, deformation, and vibration exceeding the allowable value. will do

The type of foundation is a direct foundation (or shallow foundation) that transmits directly to the ground with a foundation plate without using piles, etc., if the ground can sufficiently support the load of the structure, and a direct foundation (or shallow foundation) that does not have sufficient bearing capacity of the ground or subsidence. In case of excessive occurrence, it can be roughly classified as a deep foundation that transmits the load of the structure to the lower ground with sufficiently large bearing capacity using piles, piers, caisson, etc.

On the other hand, a top-base foundation ('top pile') that forms a foundation directly on the reinforced ground by reinforcing the ground with a top-shaped concrete block and filling crushed stone without forming a support pile on the ground with insufficient bearing capacity. Also called 'basic') is known.

In the case of the above-mentioned top base foundation, there is a problem in that the process is complicated due to essential processes such as installation of a top-type concrete block, welding of connecting reinforcing bars, and compaction of filling crushed stone, and thus construction cost is increased.

Republic of Korea Patent Publication No. 10-0721209 (May 23, 2007)

The present invention induces a similar layered ground by artificially forming a hard layer on the soft ground to be reinforced, and inducing a similar layered ground that can secure bearing capacity by forming an acupressure concrete base plate on which a small column-shaped acupressure pile is distributed. It provides the basic technique.

According to an aspect of the present invention, the step of stopping the upper part of the soft ground to be reinforced; forming pseudo-layered soils by laying a crushed stone mixed with crushed stone or sandy soil on the still soft ground to form a hard layer of a certain thickness; Installing the acupressure plate mold such that the tubular acupressure protrusion of the acupressure plate mold is distributed with a plurality of tubular acupressure protrusions having a flat bottom surface, an open top, and a hollow portion having a predetermined height; Concrete is filled in the hollow portion of the tubular acupressure protrusion to form an acupressure pile by pouring concrete on the acupressure plate mold and curing it to form an acupressure concrete base plate, a similar layered ground induction foundation method is provided.

The acupressure plate mold includes a plurality of unit acupressure plate molds. In this case, the step of installing the acupressure plate mold may include installing a plurality of unit acupressure plate molds by binding the side ends of the unit acupressure plate molds. .

A plurality of the cylindrical acupressure protrusions may be formed in a grid shape.

The unit acupressure plate mold may have a quadrangular shape, and a fastening ring may be formed at side ends adjacent to each other of the unit acupressure plate mold of the quadrangular shape, and a fastening groove to which the fastening rings are fastened may be formed at the other adjacent side ends.

The spacing (S) between the centers of the acupressure piles adjacent to each other may be 2.5 times or more (S ≥ 2.5B) of the width or diameter (B) of the bottom of the acupressure piles.

The formation height (H) of the hard layer may be a value obtained by multiplying the width or diameter (B) of the acupressure file by 0.5 to 2 (0.5B≤H≤2B).

The hollow portion of the acupressure protrusion may have a tapered shape in which the cross-section is reduced toward the bottom.

According to an embodiment of the present invention, it is possible to secure bearing capacity by forming an artificially hard layer on the soft ground to be reinforced to form a similar layered ground, and forming an acupressure concrete base plate on which a small column-shaped acupressure pile is distributed. have.

1 is a flowchart of a similar stratified ground induction foundation method according to an embodiment of the present invention.
Figure 2 is a flow chart of a similar stratified ground induction foundation method according to an embodiment of the present invention.
3 is a view from above of a unit acupressure plate mold of a similar layered ground induction basic method according to an embodiment of the present invention.
Figure 4 is a view from the bottom of the unit acupressure plate mold of the similar layered ground induction basic method according to an embodiment of the present invention.
5 is a view for explaining a method of installing a pressure plate mold of a similar layered ground induction foundation method according to an embodiment of the present invention.
6 and 7 are views for explaining the mechanism of the similar stratified ground induction foundation method according to an embodiment of the present invention.
8 is a graph relating to the settlement influence factor (Settlement Influence Factor) of the stratified ground.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, an embodiment of the similar layered ground induction foundation method according to the present invention will be described in detail with reference to the accompanying drawings, and in the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numbers and A duplicate description will be omitted.

1 is a flowchart of a similar layered ground induction foundation method according to an embodiment of the present invention, and FIG. 2 is a flowchart of a similar layered ground induction foundation method according to an embodiment of the present invention. And, FIG. 3 is a view from above of a unit acupressure plate mold of a similar layered ground induction basic method according to an embodiment of the present invention, and FIG. 4 is a unit acupressure plate mold of a similar layered ground induction basic method according to an embodiment of the present invention. is a view viewed from below, and FIG. 5 is a view for explaining a method of installing a pressure plate mold of a similar layered ground induction basic method according to an embodiment of the present invention.

2 to 5, the soft ground 12, the hard layer 14, the similar layered ground 16, the acupressure plate mold 17, the unit acupressure plate mold 18, the cylindrical acupressure protrusion 20, the hollow part 22 ), the concrete 23, the acupressure pile 24, the acupressure concrete base plate 26, the fastening ring 28, and the fastening groove 30 are shown.

The similar layered ground induction foundation method according to this embodiment comprises the steps of: suspending the upper portion of the soft ground 12 to be reinforced; Placing crushed stone or sandy soil mixed crushed stone on the stationary soft ground 12 to form a hard layer 14 of a certain thickness to form pseudo-layered soils; The tubular acupressure protrusion 20 of the acupressure plate mold 17 in which a plurality of tubular acupressure protrusions 20 having a hollow part 22 having a flat bottom surface and an open top having a predetermined height are distributed, the hard layer 14 ) and installing a pressure plate mold 17 to face; Concrete 23 is poured on the upper part of the acupressure plate mold 17 so that the hollow part 22 of the cylindrical acupressure protrusion 20 is filled with the concrete 23 to form the acupressure pile 24, and the acupressure concrete base plate 26 is cured. comprising the step of forming

2 is a flowchart of the similar stratified ground induction foundation method according to the present embodiment. With reference to FIG. 2, the similar stratified ground induction foundation method according to this embodiment will be described in detail.

First, as shown in Fig. 2 (a), the upper portion of the soft ground 12 to be reinforced is stopped (S100). The soft ground 12, which is concerned about subsidence and lack of support for the upper structure, is arranged flat and evenly. Here, the upper structure means a structure built or placed on the upper part of the foundation reinforced according to this embodiment, such as a building, a pier, a culvert, a sewage pipe, an underground parking lot, and a retaining wall.

In the case of sandy soil with good ground strength, grading work can be performed on the upper part of the original ground, and in the case of soft or viscous ground with low ground strength, the upper part of the ground is arranged flat and evenly, and then sandy soil is laid on the upper part of the still ground. The upper surface can be flattened.

Here, the soft ground 12 is a concept relative to the hard layer 14 to be described later, and means a ground having relatively weak bearing capacity compared to the hard layer 14 .

Next, as shown in (b) of FIG. 2, a hard layer 14 of a certain thickness is formed by laying crushed stone or crushed stone mixed with sandy soil on the top of the stationary soft ground 12 to form a similar layered ground 16 ) (Pseudo-layered soils) are formed (S200). Here, the hard layer 14 is a layer having relatively high rigidity compared to the soft ground to be reinforced, and crushed stone or a mixture of crushed stone and sandy soil may be used.

Crushed stone is an artificial aggregate manufactured by crushing and sorting rocks in a plant. In this embodiment, crushed stone with good particle size distribution in which particles of various particle sizes are evenly distributed was laid and a hard layer 14 of a certain thickness was formed.

In this way, it is possible to induce small-scale artificial pseudo-layered soils 16 (pseudo-layered soils) due to the soft ground 12 to be reinforced and the hard layer 14 formed thereon.

In the case of layered ground, in which the hard layer 14 with relatively high stiffness is located at the top and the soft layer with relatively low stiffness at the bottom, it behaves differently from the ground of a single layer when it is loaded by the foundation. Let's take a closer look.

Next, as shown in (c) and (d) of Figure 2, a plurality of tubular acupressure protrusions 20 having a hollow portion 22 having a flat surface and an open top and a predetermined height on the bottom surface Install the acupressure plate mold 17 so that the cylindrical acupressure protrusion 20 of the distributed acupressure plate mold 17 faces the hard layer 14 (S300).

The acupressure plate mold 17 serves as a formwork for forming the acupressure concrete base plate 26 in which countless small column-shaped acupressure piles are distributed, and the concrete 23 is placed on the acupressure plate mold 17 in the field. By pouring and nurturing, a plurality of acupressure piles 24 at the lower part of which are distributed acupressure concrete base plates 26 can be formed. The upper structure described above may be placed on the upper portion of the acupressure concrete base plate 26 .

The acupressure plate mold 17 is a plate in which a plurality of tubular acupressure protrusions 20 protrude toward the bottom, and the tubular acupressure protrusions 20 have a flat bottom surface and a hollow portion 22 having a certain height is formed. Concrete 23 is poured into the hollow part 22 and after curing, a small column-shaped acupressure pile 24 is formed to press the layered ground 16 upper part.

3 and 4 show a unit acupressure plate mold 18 according to the present embodiment. In this embodiment, a plurality of unit acupressure plate molds 18 are formed while binding the side ends of the unit acupressure plate molds 18 adjacent to each other. It presents a form of forming a single acupressure plate mold 17 by installing it on the hard layer 14 .

The unit acupressure plate mold 18 may be made of a plastic material having a size of about 1 m × 1 m or less so that an operator can easily handle it.

On the other hand, FIG. 5 shows the assembly state of the unit acupressure plate mold 18, and the unit acupressure plate mold 18 according to this embodiment has a rectangular shape, and the side ends of the unit acupressure plate mold 18 of the rectangular shape are adjacent to each other. The fastening ring 28 is formed, and the fastening groove 30 to which the fastening ring 28 is fastened is formed at the other side ends adjacent to each other.

As shown in FIG. 5, in the process of installing the unit acupressure plate mold 18, the fastening ring 28 of the unit acupressure plate mold 18 is attached to the fastening groove 30 of the adjacent unit acupressure plate mold 18. Install the unit acupressure plate mold 18 so that they are connected to each other.

On the other hand, since the unit acupressure plate mold 18 is made of a thin plastic material, it can be stacked and transported. At this time, by forming the hollow part 22 of the acupressure protrusion in a tapered shape in which the cross-section is reduced toward the bottom to facilitate stacking, the unit acupressure plate mold 18 is overlapped with each other to reduce the volume so that the transport can facilitate the handling of the operator. have.

Next, as shown in (e) of FIG. 2, the concrete 23 is filled in the hollow part 22 of the cylindrical acupressure protrusion 20 to form the acupressure pile 24. Concrete on the acupressure plate mold 17 upper part (23) is poured and cured to form the acupressure concrete base plate 26 (S400). When the acupressure plate mold 17 is placed on the hard layer 14 of the layered ground and the unconsolidated concrete 23 is poured thereon and cured, the acupressure file in the form of countless small columns as shown in FIG. 2 (e) (e) 24) presses the upper part of the layered ground 16. The above-described upper structure may be built on the acupressure concrete base plate 26 . The load of the upper structure is transmitted to the layered ground 16 through countless acupressure piles 24 of the acupressure concrete base plate 26 .

6 and 7 are views for explaining the mechanism of the similar stratified ground induction foundation method according to the present embodiment.

6 and 7 show a shallow continuous foundation supported by Layered Soils with a hard soil layer 14 formed over a fairly deep soft soil layer 12 .

Here, the physical properties of the two soil layers are shown in Table 1 below.

soil layer unit weight internal friction angle of soil adhesiveness Upper (hard soil layer)

lower (soft soil)

When the ultimate load per unit area (q _u ) is applied in the layered ground as described above, the fracture surface in the soil is as shown in FIG. 6 , and a closer look at it is as follows.

As shown in (a) of Figure 6, if the formation height (H) of the hard layer 14 is relatively smaller than the base width (B), penetration shear failure occurs in the upper hard layer 14, In the lower soft ground (12), total shear failure occurs.

On the other hand, as shown in (b) of FIG. 6, if the formation height H of the hard layer 14 is relatively large, the fracture surface occurs only in the upper hard layer 14, which is the upper limit of the ultimate bearing force.

The relative formation height (H) of the hard layer 14 with respect to the base width (B) for inducing penetration shear failure in FIG. According to a recent study (Jie Han, 2014), it is reported that penetration shear failure occurs when the formation height (H) of the hard layer 14 is approximately 0.5B to 1.5B.

The similar layered ground induction foundation method according to the present invention, as shown in FIG. 7, artificially forms a hard layer 14 with a relatively high rigidity crushed stone layer on the soft ground 12, and for that purpose, cast-in-place By forming the acupressure concrete base plate 26 in which innumerable small small column-shaped acupressure piles 24 are distributed through the (16) relates to the construction method of forming the foundation so that penetration shear failure is induced.

According to this foundation method, since a relatively thin hard layer 14 is formed on the soft ground 12, the effect of material cost reduction is greater than that of other shallow foundations. However, as described above, since it is not currently clear about the relative height (H) of the hard layer (14) with respect to the width (B) of the foundation for inducing penetration shear failure, in the present invention, the settlement amount calculation method in the stratified ground As a result, we want to propose the maximum formation height (H) of the hard layer 14 made of crushed stone or sand mixed with crushed stone. That is, the formation height (H) of the hard layer 14 according to the present invention is a value obtained by multiplying the width or diameter (B) of the underside of the acupressure pile 24 by 0.5 to 2 (0.5B≤H≤2B) ) suggest that If the acupressure file 24 has a rectangular cross section, use a value multiplied by 0.5 to 2 to the width (B) of the base, and 0.5 to the diameter (B) of the bottom when the acupressure file 24 is a circular cross section A value multiplied by 2 is used.

According to Jie Han research (2014), penetration shear failure occurs when the formation height (H) of the hard layer 14 is approximately 0.5B to 1.5B, but considering the safety side, the maximum formation height ( H) is proposed as the value (2B) multiplied by 2 to the width or diameter (B) of the acupressure pile (24). For example, if the formation height (H) of the hard layer 14 is 2B, even if penetration shear failure is not induced, a total shear failure may occur in the hard layer 14. In this case, the ultimate bearing capacity is greater than that during penetration shear failure. It can be a safety side design.

8 is a graph of the influence coefficient of settlement in the stratified ground. The elastic modulus of the hard layer 14 made of crushed stone or sandy soil mixed with crushed stone is 100 to 600 Mpa, and the elastic modulus of the soft ground to be reinforced is 2.4. Since ~ 20 Mpa, according to the graph shown in FIG. 8, the settlement amount influence coefficient becomes 0.08 ~ 0.28, which can be said to be good as ground reinforcement. In the graph of FIG. 8 , B is the foundation width and H is the depth of the hard layer.

On the other hand, when the penetration shear failure of FIG. 6(a) is induced, the ultimate bearing capacity (q _u ) proposed by Meyerhof and Hanna (1978) and Meyerhof (1974) is as follows [Equation 1].

[Equation 1]

here,

Since the above extreme bearing capacity is generated in the lower ground of each of the acupressure piles 24, the total ultimate bearing capacity of the reinforcement ground will be the value obtained by multiplying the ultimate bearing capacity according to [Equation 1] by the total number of the acupressure piles 24 .

However, in this case, since the separation distance between the acupressure piles 24 adjacent to each other is maintained at a distance that can be excluded, in this embodiment, in order to facilitate the calculation of the ultimate bearing capacity, the acupressure piles 24 adjacent to each other ) to maintain the spacing (S) between the centers of 2.5 times or more (S ≥ 2.5B) of the width or diameter (B) of the bottom of the acupressure pile (24).

When the acupressure file 24 has a rectangular cross section, it maintains 2.5 times or more (S ≥ 2.5B) of the width (B) of the bottom surface, and 2.5 of the diameter (B) of the bottom surface when the acupressure file 24 has a circular cross section Maintain more than double (S ≥ 2.5B).

In order to form the gap (S) between the centers of the acupressure piles 24 formed according to the pouring and curing of the concrete 23 as described above, the bottom surface of the hollow part 22 of the cylindrical acupressure protrusion 20 is to be formed. It is formed to be the same as the bottom surface of the acupressure file (24). That is, the concrete 23 is poured in a state where the center distance (S) between the cylindrical acupressure protrusions 20 formed in the acupressure plate mold 17 is 2.5 times the width or diameter (B) of the bottom of the hollow part 22, and When cured, the interval between the acupressure piles 24 of the acupressure concrete base plate 26 is approximately 2.5 times or more of the width of the acupressure piles 24 .

In this embodiment, since the thickness of the acupressure plate mold 17 is very thin relative to the width or diameter B of the acupressure file 24, the width of the bottom of the acupressure protrusion and the width of the bottom of the hollow part 22 are Almost the same.

Although the above has been described with reference to the preferred embodiment of the present invention, those of ordinary skill in the art can variously change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that modifications and variations are possible.

Many embodiments other than those described above are within the scope of the claims of the present invention.

12: soft ground 14: hard layer
16: pseudo-lamellar ground 17: acupressure plate mold
18: unit acupressure plate mold 20: cylindrical acupressure stone
22: hollow part 23: concrete
24: acupressure file 26: acupressure concrete base plate
28: fastening hook 30: fastening groove

Claims (7)

The step of stopping the upper part of the soft ground to be reinforced;
forming pseudo-layered soils by installing crushed stone or crushed stone mixed with sandy soil on the still soft ground to form a hard layer of a certain thickness;
The acupressure plate mold is widely laid in the hard layer so that the cylindrical acupressure protrusion of the acupressure plate mold has a flat bottom, the top is open, and a plurality of tubular acupressure protrusions having a hollow part having a certain height are distributed to face the hard layer. step of;
Concrete is filled in the hollow part of the cylindrical acupressure protrusion to form an acupressure pile, and pouring and curing concrete on the acupressure plate mold to form an acupressure concrete base plate on the hard layer,
The spacing (S) between the centers of the acupressure piles adjacent to each other is 2.5 times or more (S ≥ 2.5B) of the width or diameter (B) of the bottom of the acupressure piles,
The formation height (H) of the hard layer is a value obtained by multiplying the width or diameter (B) of the acupressure pile by 0.5 to a value multiplied by 2 (0.5B≤H≤2B), a similar layered ground induction foundation Method.
According to claim 1,
The acupressure plate mold,
Includes a plurality of unit acupressure plate mold,
The step of installing the acupressure plate mold,
A similar layered ground induction basic method, characterized in that it comprises the step of installing a plurality of the unit acupressure plate molds by binding the side ends of the unit acupressure plate mold.
According to claim 1,
A plurality of the cylindrical acupressure protrusions, characterized in that formed on a grid, a similar layered ground induction foundation method.
3. The method of claim 2,
The unit acupressure plate mold forms a square shape,
A similar layered ground induction basic method, characterized in that a fastening ring is formed at the adjacent side ends of the unit acupressure plate mold in the form of a square, and a fastening groove to which the fastening rings are fastened is formed at the other adjacent side ends.
delete delete According to claim 1,
The hollow part of the acupressure protrusion,
A similar layered ground induction foundation method, characterized in that it has a tapered shape in which the cross section is reduced toward the bottom.

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