KR102611456B1 - Top-down method of horizontal part for remodeling construction - Google Patents

Abstract

The present invention divides the slab into a reverse driving section, which is the outer part of the slab to support earth pressure, and a forward driving section, which is the remaining slab inside, during excavation work for underground structure construction in remodeling work, thereby minimizing the impact on adjacent buildings and improving economic efficiency. This is about the horizontal partial counter-punching method for remodeling construction that can be secured.
The present invention is intended to construct an underground structure equipped with multiple layers of slabs by excavating the ground adjacent to the existing structure during remodeling work. (a) An earth retaining system in which prestress is introduced to equalize the slab reaction force acting on the outer portion of the slab of each floor. Constructing a wall at the boundary of a trench in the ground; (b) constructing the outer portion of the first floor slab above ground; (c) Excavate the ground below the slab constructed just before and remove it to the depth at which the basement slab directly below will be constructed, and construct the outer section of the slab on top of the removed ground in the same manner as the outer section of the slab on the first floor above ground. Performing the counter-punching construction process at least once; (d) excavating the ground below the lowest basement slab, removing the ground to the depth at which the base plate is to be constructed, and constructing the base plate on top of the removed ground; and (e) completing each floor slab by sequentially constructing the remaining internal slabs of the outer portion of the slab constructed on the upper part of the base plate from the bottom to the top; It is characterized by including.

Description

{Top-down method of horizontal part for remodeling construction}

The present invention divides the slab into a reverse driving section, which is the outer part of the slab to support earth pressure, and a forward driving section, which is the remaining slab inside, during excavation work for underground structure construction in remodeling work, thereby minimizing the impact on adjacent buildings and improving economic efficiency. This is about the horizontal partial counter-punching method for remodeling construction that can be secured.

Recently, remodeling work to renovate existing aging buildings through expansion, renovation, or major repairs has been actively underway.

Most apartment complexes built in the past have limited parking spaces and are often located on the ground. However, as the number of vehicles increases, parking difficulties are worsening in aging apartment complexes, while apartment complexes without ground parking lots are becoming more common. Accordingly, when remodeling an apartment complex, an underground parking lot is often built on the ground between neighboring apartment buildings to secure parking space.

In order to construct an underground parking lot in this remodeling project, excavation work must be performed while the existing building remains on the ground. Therefore, special care must be taken when excavating to avoid affecting existing adjacent buildings due to ground subsidence.

In addition, since the boundary of the excavation is very close to the existing building and a high overhead load is applied to the ground due to the surrounding existing buildings, the earth pressure is higher than usual and the load burden on the temporary retaining material is large. However, the conventional method of supporting temporary earth retaining by installing struts and temporary columns before pouring the reinforced concrete beam and slab requires complicated strut installation work, inconvenient construction due to the interference of the struts, and has a risk of subsidence when adjacent buildings are close.

Accordingly, in remodeling work, the back-breaking method can be applied to construct an underground structure while the existing building remains nearby.

The counter-drilling method is a method that installs a retaining wall to support earth pressure, installs vertical members in the ground, and then carries out drilling and basement slab construction at the same time. The general counter-punching method has the advantage of being able to work on the ground and underground simultaneously, shortening the construction period, having less impact on adjacent buildings, excellent earth retaining stability, and allowing the first floor slab to be used as a workshop by pre-constructing it.

However, if the counter-punching method is applied to remodeling work to build a new underground parking lot between existing main buildings, the impact on adjacent buildings can be minimized, but since the building is not constructed on the ground, the effect is shortened by construction period or by utilizing the first floor slab. is insignificant. In addition, in cases where the excavation area is large compared to the depth, such as in an underground parking lot, the effectiveness of the reverse driving method is limited, and the construction cost is higher than the general sequential driving method of constructing a reinforced concrete structure upward, making it uneconomical.

KR 10-0605514 B1 KR 10-0912574 B1

In order to solve the above problems, the present invention is a horizontal partial counter-punching method for remodeling construction that can secure economic feasibility while minimizing the impact on adjacent buildings when excavating the ground adjacent to an existing structure to construct an underground structure in remodeling construction. We would like to provide.

The present invention according to a preferred embodiment is to construct an underground structure equipped with a plurality of layers of slabs by excavating the ground adjacent to the existing structure during remodeling work. (a) A slab in which prestress is introduced and acts on the outer portion of the slab of each floor. Constructing an earth retaining wall that equalizes the reaction force at the boundary of the ground excavation; (b) constructing the outer portion of the first floor slab above ground; (c) Excavate the ground below the slab constructed just before and remove it to the depth at which the basement slab directly below will be constructed, and construct the outer section of the slab on top of the removed ground in the same manner as the outer section of the slab on the first floor above ground. Performing the counter-punching construction process at least once; (d) excavating the ground below the lowest basement slab, removing the ground to the depth at which the base plate is to be constructed, and constructing the base plate on top of the removed ground; and (e) completing each floor slab by sequentially constructing the remaining internal slabs of the outer portion of the slab constructed on the upper part of the base plate from the bottom to the top; Including, the retaining wall is installed in the ground so as to be spaced apart from each other in the lateral direction and is composed of concrete piles installed in the ground between the synthetic pile to which the prestress is introduced and the neighboring synthetic pile, and the synthetic pile is a perforation formed in the ground. Steel piles of H-shaped cross section inserted inside the hole; A concrete pile portion poured into the drilling hole and having the steel pile embedded therein; A plurality of tension members are bent and arranged on both sides of the web of the steel pile according to the moment due to the back earth pressure and are provided non-attached inside the concrete pile portion to introduce prestress into the concrete pile portion; An upper anchor provided on the upper part of the tendon and completely or partially embedded in the concrete pile part; And a lower anchor provided at the lower part of the tendon and embedded in the concrete pile part; It consists of a wedge barrel embedded in the inside of the concrete pile portion, which has a cylindrical shape with the top and bottom open, and a wedge hole of the upper and lower narrows is formed inside, and is inserted into the wedge hole of the wedge barrel to move downward within the wedge hole. A horizontal partial reverse blow for remodeling construction, characterized in that it consists of a wedge that pressurizes and fixes the outer peripheral surface of the tendon member, a cap member that closes the open upper part of the wedge barrel as the tendon penetrates, and a pressure spring provided between the cap member and the wedge. Provides a method.

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The present invention according to another preferred embodiment is that the tension member penetrates both sides of the lower web of the steel pile so that the lower anchor is supported by hanging on the lower surface, and is temporarily fixed so that it can be removed from the steel pile by introducing the tension force of the tension member. A horizontal partial counter-punching method for remodeling construction is provided, characterized in that a fixing plate is provided.

The present invention according to another preferred embodiment is for tensioning a tension member at the top of the steel pile, the lower part is opened to accommodate the top of the steel pile therein, and a plurality of tension members are penetrated and drawn out to the top. It provides a horizontal partial counter-punching method for remodeling construction, which is characterized in that it is provided with a reaction force.

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The present invention according to another preferred embodiment is further provided with sub-tension members on both sides of the web of the steel pile, which are non-attached to the inside of the concrete pile part and introduce prestress to the steel pile, and the upper part of the tension member is provided by the upper anchorage. It is anchored to the upper part of the concrete pile, and the lower part is anchored to the lower part of the concrete pile by the lower anchor embedded in the inside of the concrete pile, and the upper part of the sub tension member is anchored to the steel pile by the upper sub anchor provided at the top of the reaction arm. It provides a horizontal partial back hammering method for remodeling construction, characterized in that the upper part is anchored, and the lower part is anchored to the lower part of the steel pile by a lower sub anchor provided at the lower part of the anchor anchor fixed to the lower end of the steel pile.

According to the present invention, when excavating for the construction of an underground structure in a remodeling project, the outer part of the ring-shaped slab is pre-constructed by counter-pounding, thereby minimizing the impact on adjacent buildings and effectively supporting the surrounding earth pressure while reducing the counter-impact area, which requires high construction costs. A horizontal partial counter-punching method for remodeling construction that can be minimized can be provided.

According to the present invention, it is possible to provide a horizontal partial back-pounding method for remodeling construction that can secure economic feasibility by maximizing the sequential construction area by sequentially constructing the remaining slab inside, which is structurally unnecessary for earth pressure support, from the bottom to the top after back-pounding construction on the outer part of the slab. You can.

1 is a diagram showing step (a) of the present invention.
Figure 2 is a diagram showing step (b) of the present invention.
3 to 4 are diagrams showing step (c) of the present invention.
Figure 5 is a perspective view showing a state in which a slab outer portion is constructed on the ground adjacent to an existing structure.
Figure 6 is a diagram showing step (d) of the present invention.
7 to 9 are diagrams showing step (e) of the present invention.
Figure 10 is a perspective view showing a state in which the remaining slab is constructed inside the outer portion of the slab.
Figure 11 is a diagram showing the reaction force acting on the slabs of each underground floor.
Figure 12 is a cross-sectional view showing a retaining wall for introducing prestress.
Figure 13 is a perspective view showing a retaining wall for introducing prestress.
Figure 14 is a perspective view showing a composite pile.
Figure 15 is a perspective view showing the upper anchorage details of tendons in a composite pile.
Figure 16 is a perspective view showing details of the lower anchorage of tendons in a composite pile.
Figure 17 is a perspective view showing a steel pile provided with a temporary fixing plate.
Figure 18 is a bottom perspective view showing the reaction arm.
Figure 19 is a perspective view showing a composite pile with a reaction force installed on the top of the steel pile.
Figure 20 is a cross-sectional view showing a spring anchored upper anchor.
Figure 21 is a perspective view showing the settlement state of the tendon material for prestress sharing.
Figure 22 is a cross-sectional view showing the upper anchorage details of the sub-tensioner in Figure 21.
FIG. 23 is a cross-sectional view showing details of the lower anchorage of the sub-tension member in FIG. 21.

Hereinafter, the present invention will be described in detail according to the accompanying drawings and preferred embodiments.

Figure 1 is a diagram showing step (a) of the present invention, Figure 2 is a diagram showing step (b) of the present invention, and Figures 3 and 4 are diagrams showing step (c) of the present invention. And Figure 5 is a perspective view showing the state in which the slab outer part is constructed on the ground adjacent to the existing structure. In addition, Figure 6 is a view showing step (d) of the present invention, Figures 7 to 9 are views showing step (e) of the present invention, and Figure 10 shows a state in which the remaining slab is constructed inside the outer portion of the slab. It is a perspective view showing.

As shown in Figures 1 to 10, the horizontal partial counter-punching method for remodeling work of the present invention involves excavating the ground (2) adjacent to the existing structure (1) in the remodeling work to create an underground structure equipped with a plurality of layers of slabs (4). For construction, (a) constructing an earth retaining wall (3) on the boundary of the excavation of the ground (2); (b) constructing the outer portion (4a) of the ground floor slab (4); (c) The lower ground (2) of the slab (4) constructed immediately before is excavated and removed to the ground (2) at the depth at which the immediately lower basement slab (4) will be constructed, and the slab is placed on top of the removed ground (2). Performing the counter-punching construction process of constructing the outer portion 4a of (4) at least once; (d) Excavating the ground (2) below the lowest basement slab to remove the ground (2) at the depth at which the base plate (6) is to be constructed, and constructing the base plate (6) on top of the removed ground (2). ; and (e) completing each floor slab (4) by sequentially constructing the inner remaining slab (4b) of the slab outer portion (4a) constructed on the upper part of the base plate (6) from the bottom to the top; It is characterized by including.

The present invention is intended to provide a horizontal partial counter-punching method for remodeling construction that can secure economic feasibility while minimizing the impact on adjacent buildings when excavating for the construction of underground structures in remodeling construction.

The present invention can be applied to additional construction of an underground structure, such as an underground parking lot, on the ground (2) adjacent to the existing structure (1) when remodeling an aging apartment complex.

The newly constructed underground structure includes multiple layers of slabs (4).

In the present invention, (a) first, an earth retaining wall (3) is constructed at the boundary of the excavation of the ground (2) (FIG. 1).

As with the general counter-punching method, an earth retaining wall (3) is constructed at the boundary of the excavation of the ground (2) where the underground structure will be constructed.

The retaining wall 3 may be CIP, SCW, slurry wall, etc.

The top of the earth retaining wall (3) may be fixed to a new foundation (11') extended to the end of the existing building foundation (11).

Next, (b) the outer portion 4a of the ground floor slab 4 is constructed (Figure 2).

In remodeling construction, the area of the new basement floor is relatively large compared to the excavation depth. Therefore, the entire slab is not required to support the surrounding earth pressure acting on the retaining wall. Accordingly, instead of pre-constructing the entire area of the target slab, only the outer part of the support slab (4) is pre-constructed to form a ring shape, thereby allowing the slab (4) to effectively support the surrounding earth pressure, while minimizing the counter-hitting area, which requires a lot of construction costs, and reducing the net hitting area. Economic feasibility can be secured by maximizing .

To this end, in step (b), only the outer portion 4a of the ground floor slab 4, which is the starting point of the counter-punching method, is first partially constructed.

Since the pre-constructed slab outer portion 4a is formed in a ring shape, the surrounding earth pressure can be effectively supported by the slab compression strength in all directions. In addition, during the counter-pounding process, only the outer portion of the slab (4a) is pre-constructed, and the central portion remains empty, making it easy to take in and out materials or equipment or discharge excavated soil through the central portion.

Before constructing the slab (4) on the first floor above ground, a vertical member (5) for counter-pounding capable of supporting the slab (4) can be pre-constructed on the outer part of the underground construction site for slab counter-pounding construction.

The outer portion (4a) of the ground first floor slab (4) is supported on the vertical member (5) for counter hitting.

A bracket and a steel beam for supporting the slab 4 may be installed on the vertical member 5 for counter striking (not shown).

The vertical member 5 for counter-punching may be a temporary center pile that is pulled out and removed after construction of a permanent column, or it may be a main column of an underground structure, that is, a permanent column.

And (c) the lower ground (2) of the slab (4) constructed immediately before is excavated to remove the ground (2) at the depth at which the immediately lower basement slab (4) will be constructed, and placed on top of the removed ground (2). The counter-punching construction process for constructing the outer portion 4a of the slab 4 is performed at least once (FIGS. 3 and 4).

That is, after constructing the outer portion 4a of the first floor slab above ground, the basement slabs 4 below the first floor slab 4 above ground are constructed using a counter-punching method.

The basement slabs (4) are supported on vertical members (5) for counter striking.

The basement slabs (4), like the first-floor slabs (4), are also constructed with the central portion empty and only the outer portion (4a) constructed.

Specifically, the lower ground (2) of the first floor slab (4) above ground is excavated for one layer, and then the outer part (4a) of the first basement floor slab is constructed (FIG. 3). Afterwards, the ground (2) below the level of the slab (4) on the first basement floor is excavated by one layer, and then the outer part (4a) of the slab on the second basement floor (FIG. 4) is constructed. In the same way, construction is carried out to the outer part (4a) of the lowest basement slab.

Accordingly, as shown in FIG. 5, a multiple-layer slab outer portion 4a is constructed on the ground adjacent to the existing structure 1.

In step (c) above, when back-pounding the basement slab (4), even if only the outer portion (4a) of the slab (4) is pre-constructed, the ground (2) excavation covers the entire area of the construction site.

Afterwards, (d) the ground (2) under the lowest basement slab is excavated to remove the ground (2) at the depth at which the base plate (6) is to be constructed, and the base plate (6) is constructed on top of the removed ground (2). (Figure 6).

After constructing the outer part of the lowest underground slab (4a), the ground (2) below the lowest slab level is excavated and the ground (2) is removed to the depth at which the foundation plate (6) is to be constructed. Afterwards, a base plate (6) is constructed on top of the removed ground (2).

The base plate (6) is constructed over the entire area of the bottom of the excavation.

Finally, (e) the remaining slabs (4b) are sequentially constructed from the bottom to the top inside the slab outer portion (4a) constructed on top of the base plate (6) to complete each floor slab (4) (Figs. 7 to 7) Figure 9).

After constructing the base plate 6, the remaining slab 4b inside the outer portion 4a of each floor slab previously constructed in steps (b) and (c) is constructed.

The remaining slabs 4b are sequentially constructed upward from the lowest basement floor to the first floor above ground. If explained with reference to the drawing, the order of constructing the remaining slab (4b) on the second basement floor (FIG. 7), then constructing the remaining slab (4b) on the first basement floor (FIG. 8), and then constructing the remaining slab (4b) on the first floor above ground. It can be carried out (Figure 9).

Accordingly, as shown in FIG. 10, construction of a multi-layer slab 4 with a remaining slab 4b inside the slab outer portion 4a adjacent to the existing structure 1 is completed.

The pillar members 7 in the remaining slab 4b section can be sequentially constructed at the same time as the remaining slab 4b is being constructed.

When the vertical member 5 for counter-punching constructed in step (b) is a temporary center pile, when constructing the column member 7 in the remaining slab section 4b, the column member, which is a permanent column, is also installed in the slab outer section 4a. (7) can be constructed simultaneously.

The vertical member for reverse driving (5), which is a temporary center pile, is pulled out and removed after the construction of the underground structure is completed.

In this way, in the case where the slab 4 is divided into a reverse driving section and a sequential driving section for the construction of an underground structure in a remodeling work, that is, the outer part of the slab (4a) required for earth pressure support is constructed by reverse pounding, and is structurally used to support earth pressure. If the unnecessary remaining internal slab 4a is constructed sequentially, it is possible to secure economic feasibility while effectively supporting the surrounding earth pressure.

Figure 11 is a diagram showing the reaction force acting on the slab of each underground floor, and Figure 12 is a cross-sectional view showing an earth retaining wall for introducing prestress.

As shown in FIG. 12, in step (a), prestress is introduced into the retaining wall 3 to equalize the slab reaction force acting on the outer portion 4a of the slab on each floor, and in step (b) and ( In step c), the section of the slab outer section 4a that is subjected to reverse pounding construction can be configured so that each floor is set identically.

In a typical field, an earth retaining wall has a cantilever structure to resist earth pressure. Therefore, the amount of earth pressure acting on the retaining wall during excavation is minimum at the top of the retaining wall, and increases toward the lower part of the retaining wall, reaching a maximum at the bottom.

On the other hand, when fixing the top of the earth retaining wall (3) to the new foundation (11') constructed as an extension to the end of the existing building foundation (11) in remodeling work, the earth retaining wall (3) is a support structure at both upper and lower ends, so it is located near the center. Earth pressure is maximum.

In this way, the surrounding earth pressure acting on the retaining wall 3 varies in size depending on the vertical depth.

Accordingly, in the case where no prestress is introduced, as can be seen in (a) of FIG. 11, the size of the slab reaction force acting on each floor slab (4) of the underground structure is also bound to be different. Based on the reaction force, each floor slab (4) ), the boundary line dividing the outer portion (4a) of each floor slab and the remaining slab (4b) does not match.

In this case, if only the part for structurally supporting earth pressure is set as the outer part 4a, the horizontal length of each floor is different, which not only makes construction cumbersome, but also makes the arrangement of the vertical members 5 for counter striking complicated. In addition, if the slab outer part 4a is set based on the floor with the longest horizontal length, the sequential section of the other floors is reduced accordingly, making it uneconomical.

Therefore, the reaction force acting on each floor must be equalized as much as possible to ensure constructability by maintaining the horizontal length of the outer portion 4a of each floor at the structurally necessary level, and economic feasibility must be achieved by securing the sequential section as much as possible.

For this purpose, prestress is introduced into the retaining wall (3) to offset the back earth pressure, thereby equalizing it to a similar level depending on the height of the retaining wall (3).

Specifically, when the upper end of the retaining wall (3) is fixed to the new foundation (11') and the retaining wall (3) has a structure with both ends supported (i.e., fixed at the bottom, hinged at the top), the retaining wall (3) is bent in the central part. Moment has the greatest effect. Therefore, by applying prestress to the front side of the retaining wall (3), that is, the trench side, to offset the bending moment caused by the back earth pressure, the reaction force acting on each floor slab (4) can be adjusted to a similar level.

As a result, the range of the outer portion 4a of each floor slab 4 can be similarly adjusted, thereby ensuring constructability and economic efficiency.

Figure 11 (b) shows the reaction force acting on the slab on each underground floor when prestress is introduced. It can be seen that the difference in reaction force acting on the slab on each floor is greatly reduced and equalized by the introduction of prestress.

Figure 13 is a perspective view showing a retaining wall for introducing prestress.

As shown in FIG. 13, the retaining wall 3 is installed in the ground 2 so as to be spaced apart from each other in the transverse direction, and the ground 2 is between the synthetic pile 3a into which the prestress is introduced and the neighboring synthetic pile 3a. ) It may be composed of a concrete pile (3b) installed within.

During remodeling work, it is important to minimize the impact of adjacent existing structures (1). Therefore, it is desirable to construct the retaining wall using the CIP method, which has high rigidity to suppress horizontal displacement of the backing soil and has relatively low vibration and noise.

In particular, in remodeling work, it is difficult to use large equipment for excavation work because the existing structure (1) is located adjacent to the underground construction site. However, the CIP method is suitable for remodeling work because the equipment is small.

The CIP (Cast in placed pile) method is a method of drilling the ground with an earth auger, filling the drilled ground with reinforcing bar mesh and gravel, and then injecting mortar through an injection pipe to form a pile in place.

Column retaining methods such as the CIP method often insert H-beams inside some concrete piles to reinforce the bending rigidity of the retaining wall.

Therefore, the retaining wall 3 is constructed by a column retaining method such as the CIP method, and is formed by inserting H-beams into some concrete piles and then forming them into prestressed composite piles 3a by introducing prestress into the H-beams. Earth pressure can be offset.

Figure 14 is a perspective view showing a composite pile.

As shown in FIG. 14, etc., the composite pile (3a) includes a steel pile (31) of H-shaped cross-section inserted into a drilling hole formed in the ground (2); A concrete pile portion (32) poured into the drilling hole so that the steel pile (31) is embedded therein; And a plurality of bending and arranged on both sides of the web 311 of the steel pile 31 according to the moment due to the back earth pressure and provided non-attached inside the concrete pile portion 32 to introduce prestress into the concrete pile portion 32. Jangjae Jang (33); It can be composed of:

In order to form a conventional composite pile, there is a technology to increase the bending rigidity of the H-beam steel by combining steel materials with prestress introduced on the outside of the flange of the H-beam pile (Patent No. 10-2226859).

In general, steel exhibits the same structural performance in compression and tension, so the structural benefit from prestress is not significant, whereas concrete has relatively very small tensile performance compared to compression, so introducing prestress is a big advantage. However, since the above conventional technology introduces prestress only to H-beam steel, not concrete, there is a limit to improving cross-sectional performance in the entire composite cross-section, making it structurally inefficient. In addition, since the anchoring member for anchoring the steel rod is integrally fixed to the H-beam, it is difficult to recover the H-beam after completion of basement construction, which reduces economic feasibility.

Therefore, by mainly introducing prestress into the steel pile 31 and the composite concrete pile portion 32, not only can the bending strength and rigidity of the composite pile 3a be increased and displacement reduced, but the steel pile 31 can be recovered. It is desirable to configure

The composite pile (3a) is a steel-concrete composite pile in which a steel pile (31) is embedded within a concrete pile portion (32).

The steel pile 31 is inserted into the drilled hole formed in the ground (1).

The steel pile 31 has an H-shaped cross-section (including I-shaped cross-section) shape with flanges 312 formed at right angles to both sides of the web 311.

The steel pile 31 can be manufactured from rolled section or built-up section.

The concrete pile portion 32 is formed by pouring concrete into the drilled hole so that the steel pile 31 is embedded therein.

A plurality of the synthetic piles (3a) are arranged to be spaced apart from each other, and concrete piles (3b) may be constructed between the spaced apart synthetic piles (3) (FIG. 13).

The tension member 33 is provided as a plurality of strands on one side of the steel pile 31.

The tension members 33 are provided on both sides of the web 311 of the steel pile 31, and may be made of steel bars, strands, steel wires, etc.

The tension member 33 is embedded within the concrete pile portion 32, and introduces prestress into the concrete pile portion 32 by introducing tension force.

In order to introduce prestress mainly to the concrete pile portion 32 rather than the steel pile 31 by introducing tension force to the tendon member 33, the tendon member 33 is tensioned after the concrete constituting the concrete pile portion 32 is hardened. Should be. Therefore, the tension member 33 is composed of a non-bonded tension member.

For this purpose, a protective covering 331 may be provided on the outside of the tendon 33 (FIG. 14).

That is, the tendon member 33 is not fixed to the steel pile 31 but is embedded non-attached inside the concrete pile portion 32. Therefore, with respect to the axial force when the tension member 33 is tensioned, prestress is basically not introduced into the steel pile 31, but only into the concrete pile portion 32. Therefore, the structural efficiency of the composite pile 3a can be maximized.

When introducing prestress into the concrete pile portion 32, a separating agent is applied to the surface of the steel pile 31 to prevent stress from being transmitted to the steel pile 31 due to the friction between the steel pile 31 and the concrete. It can be applied.

The tendon 33 can be bent and arranged to efficiently resist back earth pressure by introducing eccentricity due to prestress and generating a reverse moment in the composite pile 3a (FIG. 12).

At this time, the concrete pile portion 32 and the steel pile 31 can act as one body to resist earth pressure against bending deformation that occurs as prestress is introduced into the tendon 33. Regarding the compressive force, compressive prestress is mainly introduced to the concrete pile portion 32, and almost no compressive force is introduced to the H-beam steel.

In order to fix the bent position of the tendon 33, a guide bar 34 may be provided on the inside of the steel pile 31 to support the bent portion where the tendon 33 is bent (see FIG. 15, etc.).

Figure 15 is a perspective view showing the upper anchorage details of the tendon in the composite pile, and Figure 16 is a perspective view showing the lower anchorage details of the tendon in the composite pile.

As shown in FIGS. 15 and 16, an upper anchor 35 and a lower anchor 36 are provided at the upper and lower portions of the tension member 33, respectively, and the lower anchor 36 is connected to the concrete pile portion 32. ) can be buried inside.

In order to apply prestress to the concrete pile portion 32 by tensioning the tendon member 33, both ends of the tendon member 33 must be anchored inside or outside the concrete pile portion 32.

Accordingly, the upper anchor 35 and the lower anchor 36 can be coupled to the upper tension end and the lower fixed end of the tension member 33, respectively.

At this time, since there is no separate space at the bottom of the concrete pile portion 32, the lower anchor 36 can be buried inside the concrete pile portion 32.

When a strand made by twisting several strands of steel wire is used as the tension material 33, the lower anchor 36 forming the fixed end can be embedded and anchored in the concrete pile portion 32 by bulbing the lower end of the strand. (Figure 16).

The upper anchorage 35, which is a tension end, may be embedded within the concrete pile portion 32 or may be exposed to the top of the concrete pile portion 32.

Figure 17 is a perspective view showing a steel pile equipped with a temporary fixing plate.

As shown in FIGS. 16 and 17, the tension material 33 penetrates both sides of the lower web 311 of the steel pile 31 and the lower anchor 36 is supported by hanging on the lower surface, and the tension material 33 ) may be provided with a temporary fixing plate (37) that is temporarily fixed so that it can be removed from the steel pile (31) by introducing a tension force.

When the lower anchor 36 is buried and anchored within the concrete pile portion 32, the position of the lower anchor 36 must be temporarily fixed until the internal concrete forming the concrete pile portion 32 hardens.

For this purpose, a temporary fixing plate 37 can be temporarily fixed to the inside of the steel pile 31 at the location where the lower anchor 36 is to be installed. In addition, the lower fixture 36 can be positioned below the temporary fixing plate 37 with the lower end of the tension member 33 penetrating the temporary fixing plate 37.

A plurality of through holes 371 through which the tension member 33 penetrates are formed in the temporary fixing plate 37.

The temporary fixing plate 37 only fixes the position of the lower anchor 36, and prevents the tension of the tension member 33 from being transmitted to the steel pile 31 by the temporary fixing plate 37. (37) can be temporarily fixed to one side of the steel pile (31) by tack welding (W).

Therefore, when tension is introduced to the tension member 33, displacement occurs in the temporary fixing plate 37, causing the tack weld (W) portion to fall off, thereby blocking stress transmission to the steel pile 31.

The lower anchors 36 of the plurality of tension members 33 are simultaneously supported on the temporary fixing plate 37.

Accordingly, the temporary fixing plate 37 uniformly distributes the tension of the entire tendon group and transfers it to the concrete pile portion 32, thereby relieving stress concentration at the anchoring portion within the concrete pile portion 32.

Figure 18 is a bottom perspective view showing a reaction arm, and Figure 19 is a perspective view showing a composite pile with a reaction arm installed on the top of a steel pile.

As shown in FIGS. 18 and 19, the tension member 33 is placed at the top of the steel pile 31 to tension it at the top of the steel pile 31, and the lower part is opened to accommodate the steel pile 31 inside. The upper end may be accommodated, and a reaction force 38 may be provided through which a plurality of tension members 33 are penetrated and drawn upward.

In the composite pile (3a), the steel pile (31) protrudes to the upper part of the concrete pile portion (32) by a certain length and is exposed to the ground. Therefore, a reaction bar 38 can be installed on the top of the steel pile 31 to tension the tendon 33 at the top of the composite pile 3a by utilizing the portion of the steel pile 31 that protrudes upward.

The reaction arm 38 may be configured in the form of a box with an open bottom so that the upper end of the steel pile 31 is inserted and accommodated.

A plurality of through holes 381 are formed on the upper surface of the reaction arm 38 so that the upper end of the tension member 33 penetrates and is drawn upward.

Tension force can be introduced to the tension member 33 by mounting a hydraulic jack (not shown) on the upper part of the reaction arm 38 at the position of the tension member 33.

Typically, the tension of one tendon material is less than 20 tons, which is relatively small compared to the friction force between cast-in-place concrete and the surrounding ground (2). Therefore, when the tension member 33 is tensioned while the lower end of the tension member 33 is anchored to the concrete, even if the steel pile 31 temporarily bears the reaction force at the top of the tension member 33, the concrete pile portion 32 does not rise to the top.

Therefore, when the tension member 33 is tensioned using the reaction bar 38 at the top of the steel pile 31, prestress can be introduced into the concrete pile portion 32 by the tension of the tension member 33.

At this time, the upper fixture 35 is provided on the tension member 33 at the lower part of the reaction arm 38. Accordingly, when tension is introduced to the tendon 33 and the upper end of the tendon 33 is anchored to the upper anchorage 35, prestress is mainly introduced to the concrete pile portion 32.

Figure 20 is a cross-sectional view showing a spring anchored upper anchor.

As shown in Figures 20 (a) and (b), the upper anchor 35 is embedded in the interior of the concrete pile portion 32, and the upper anchor 35 has a cylindrical shape with the top and bottom open. A wedge barrel 351 having an upper and lower wedge hole 350 formed therein, the outer peripheral surface of the tension member 33 being inserted into the wedge hole 350 of the wedge barrel 351 and moving downward within the wedge hole 350. A wedge 352 that pressurizes and fixes, a cap member 353 that closes the open upper part of the wedge barrel 351 while the tension member 33 penetrates, and a cap member 353 provided between the cap member 353 and the wedge 352. It may be composed of a pressure spring 354.

Since the lower anchor 36 is a fixed end, it is fixed in a buried state within the concrete pile portion 32.

In contrast, since the upper anchor 35 is a tension member, in order to install the upper anchor 35 embedded within the concrete pile portion 32, the upper anchor 35 is embedded within the concrete pile portion 32 and then the tension member 33 ) must be tensioned to secure the upper fixture (35) to the tension member (33) in a tense state.

In other words, the upper anchorage 35 must be configured to be able to tension the tendon 33 even when it is embedded within the concrete pile portion 32 and to allow anchorage of the tensioned tendon 33. Accordingly, the upper fixture 35 is provided with a pressure spring 354 at the upper end of the wedge 352 of the wedge barrel 351 where the wedge 352 is accommodated in the wedge hole 350, and at the upper end of the wedge barrel 351. The cap member 353 can be combined to form a spring anchored upper fixture 35.

At this time, the cap member 353 may be screwed to the wedge barrel 351.

The operation process of this spring anchored upper anchor 35 is described as follows.

When the upper end of the tendon 33 is extended to expose the upper part of the synthetic pile 3a and pulled with a hydraulic jack, the wedge 352 is initially connected to the tendon 33 and the wedge 352 due to frictional force between the inner peripheral surfaces of the tendon 33 and the wedge 352. rise together Afterwards, the rise of the wedge 352 is restricted by the pressure spring 354 and the cap member 353, and only the tendon 33 is continuously pulled to introduce tension into the tendon 33. In Figure 20 (a), the tension member 33 is shown in a tense state.

After the introduction of tension to the tension member 33 is completed, the operation of the hydraulic jack is stopped and the tension member 33 is released from the hydraulic jack.

Then, the pressing spring 354 presses the wedge 352 downward so that the wedge 352 moves toward the wedge hole 350 of the wedge barrel 351. Since the inner peripheral surface of the wedge hole 350 has an upper-lower narrow shape, when the wedge 352 moves downward along the inner peripheral surface of the wedge hole 350, the wedge 352 is tightened and the tension member 33 is fixed to form the tension member 33. It settles with the tension force introduced ((b) in Figure 20).

When the upper anchor 35 is embedded inside the concrete pile portion 32, a temporary fixing plate 37 may be provided on one side of the steel pile 31 to fix the position of the upper anchor 35 (Figure 15, Figure 19, etc.). In this case, when the hydraulic jack is released while the tension member (33) is pulled by a hydraulic jack, the upper fixture (35) to which the tension member (33) is fixed moves downward due to the tension of the tension member (33), thereby fixing the temporary fixing plate (37). By applying pressure, the temporary fixing plate (37) falls off from the steel pile (31).

In addition, when the upper anchor 35 is embedded inside the concrete pile portion 32, in order to tension the tendon 33, the upper end of the tendon 33 penetrates the upper anchor 35 to the top of the composite pile 3a. It must be extended and exposed. Accordingly, a protective covering 331 is installed on the outside of the tendon 33 that protrudes to the upper part of the upper anchorage 35 and is embedded in the concrete pile 32 to maintain the non-adhered state with the concrete pile 32. It can be configured.

In some cases, the lower anchor 36 may also be configured as a spring anchor similar to the upper anchor 35.

Figure 21 is a perspective view showing the anchoring state of the tension material for prestress distribution, Figure 22 is a cross-sectional view showing the upper anchoring details of the sub-tension material in Figure 21, and Figure 23 is a lower anchoring detail of the sub-tension material in Figure 21. This is a cross-sectional view.

As shown in FIGS. 21 to 23, sub-tension members are embedded on both sides of the web 311 of the steel pile 31 in a non-attached manner to introduce prestress into the steel pile 31. (33') is further provided, the upper part of the tendon member 33 is fixed to the upper part of the concrete pile part 32 by the upper anchoring hole 35, and the lower part is embedded in the interior of the concrete pile part 32. It is anchored to the lower part of the concrete pile portion 32 by the lower anchor 36, and the upper part of the sub tension member 33' is anchored to the upper sub anchor 35' provided on the upper part of the reaction arm 38. It is fixed to the upper part of the steel pile 31, and the lower part is fixed to the lower part of the steel pile 31 by the lower sub anchorage 36' provided in the lower part of the anchorage 39 fixed to the lower end of the steel pile 31. can be established.

The size of the prestress applied to the composite pile (3a) is determined according to the size of the back earth pressure. However, if the size of the prestress is excessive, the concrete pile portion 32 may be damaged or destroyed.

Therefore, when the size of the introduced prestress is large, the steel pile 31 can be configured to bear part of the prestress.

For this purpose, a sub-tension member 33' may be further provided along with the tension member 33.

The tension member 33 is fixed to the upper and lower parts of the concrete pile portion 32 by the upper anchor 35 and lower anchor 36, respectively.

The sub-tension member 33' is respectively fixed to the upper and lower parts of the steel pile 31 by the upper sub-anchoring 35' and the lower sub-anchoring 36'.

The upper fixture 35, which fixes the upper part of the tension member 33, is embedded in the interior of the concrete pile part 32 or is mounted on the top of the concrete pile part 32 at the lower position of the reaction arm 38 to form the tension member 33. ) can be anchored to the top of the concrete pile portion (32).

The lower anchor 36 for fixing the lower part of the tendon 33 is embedded in the interior of the concrete pile 32, so that the lower part of the tendon 33 can be anchored to the lower part of the concrete pile 32.

The upper sub anchorage 35' that secures the upper part of the sub tension member 33' may be located on the upper part of the reaction arm 38 installed on the upper part of the steel pile 31.

The lower end of the sub-tension member 33' can be anchored to one side of the steel pile 31 rather than the concrete pile portion 32 by the lower sub anchorage 36'. For this purpose, a fixed anchor 39 is fixedly coupled to one side of the steel pile 31, and the lower sub anchor 36' can be supported in close contact with the fixed anchor 39 (FIG. 21).

When the sub-tension member 33' is tensioned, the tension force of the sub-tension member 33' is transmitted to the steel pile 31 through the reaction arm 38, thereby introducing prestress into the steel pile 31.

Accordingly, the tension member 33 introduces prestress to the concrete pile portion 32, and the sub-tension member 33' introduces prestress to the steel pile 31. As a result, while introducing sufficient prestress to the composite pile 3a, it is possible to reduce the burden on the concrete pile portion 32 and prevent damage or destruction of the concrete pile portion 32 due to excessive prestress.

The sub-tension member 33' is pulled out to the top of the concrete pile portion 32 and the upper end is exposed to the ground. Therefore, when recovering the steel pile 31 after completing the construction of the underground structure, the sub-tension member 33' is cut between the reaction arm 38 and the top of the concrete pile part 32, the reaction arm 38 is removed, and the steel pile ( 31) can be easily pulled out and recovered.

1: Existing structure 11: Existing building foundation
11': New foundation 2: Ground
3: Earth retaining wall 3a: Composite pile
3b: concrete pile 31: steel pile
311: web 312: flange
32: Concrete pile part 33: Tension material
33': Sub-tension material 331: Protective sheath
34: Guide bar 35: Upper fixture
35': Upper sub anchor 350: Wedge hole
351: wedge barrel 352: wedge
353: Cap member 354: Pressure spring
36: lower anchor 36': lower sub anchor
37: Temporary fixing plate 371: Through hole
38: reaction arm 381: through hole
39: fixed fixture 4: slab
4a: Slab outer part 4b: Remaining slab
5: Vertical member for counter hitting 6: Base plate
7: Column member W: Tack welding

Claims (9)

In remodeling work, the ground (2) adjacent to the existing structure (1) is excavated to construct an underground structure equipped with multiple layers of slabs (4).
(a) constructing an earth retaining wall (3) in which prestress is introduced to equalize the slab reaction force acting on the outer portion (4a) of each floor slab at the boundary of the excavation of the ground (2);
(b) constructing the outer portion (4a) of the ground floor slab (4);
(c) The lower ground (2) of the slab (4) constructed immediately before is excavated and removed to the ground (2) at the depth at which the immediately lower basement slab (4) will be constructed, and the slab is placed on top of the removed ground (2). Performing a counter-punching construction process of constructing the outer portion (4a) of (4) in the same manner as the outer portion (4a) section of the ground floor slab (4) at least once;
(d) Excavating the ground (2) below the lowest basement slab to remove the ground (2) at the depth at which the base plate (6) is to be constructed, and constructing the base plate (6) on top of the removed ground (2). ; and
(e) completing each floor slab (4) by sequentially constructing the inner remaining slab (4b) of the slab outer portion (4a) constructed on the upper part of the base plate (6) from the bottom to the top; Including,
The retaining wall (3) is installed in the ground (2) so as to be spaced apart from each other in the transverse direction, and is a concrete pile (3b) installed in the ground (2) between the synthetic pile (3a) into which the prestress is introduced and the neighboring synthetic pile (3a). ) consists of,
The composite pile (3a) includes a steel pile (31) of H-shaped cross-section inserted into a drilled hole formed in the ground (2); A concrete pile portion (32) poured into the drilling hole and into which the steel pile (31) is embedded; A plurality of tension members are bent and arranged on both sides of the web 311 of the steel pile 31 according to the moment due to the back earth pressure and are provided non-attached inside the concrete pile portion 32 to introduce prestress into the concrete pile portion 32. (33); An upper anchor (35) provided on the upper part of the tendon (33) and completely or partially embedded in the concrete pile portion (32); And a lower anchor (36) provided at the lower part of the tension member (33) and embedded in the interior of the concrete pile portion (32); It consists of
The upper fixture 35 embedded in the concrete pile portion 32 is a wedge barrel 351 having a cylindrical shape with the top and bottom open and a wedge hole 350 of the upper and lower narrows formed therein, and the wedge barrel 351 A wedge 352 is inserted into the wedge hole 350 and presses and fixes the outer peripheral surface of the tendon 33 as it moves downward within the wedge hole 350. The tendon 33 penetrates and opens the wedge barrel 351. A horizontal partial counter-punching method for remodeling construction, characterized in that it consists of a cap member 353 that closes the upper part and a pressure spring 354 provided between the cap member 353 and the wedge 352.
delete delete delete delete In paragraph 1:
The tension material 33 penetrates both sides of the lower web 311 of the steel pile 31 so that the lower anchor 36 is supported on the lower surface, and the steel pile 31 is supported by introducing the tension force of the tension material 33. A horizontal partial counter-punching method for remodeling construction, characterized in that it is provided with a temporary fixing plate (37) that is temporarily fixed so that it can be removed from.
In paragraph 1:
The upper end of the steel pile 31 is for tensioning the tension material 33 at the upper part of the steel pile 31. The lower part is opened to accommodate the upper end of the steel pile 31 therein, and a plurality of tension members 33 are provided at the upper end of the steel pile 31. A horizontal partial counter-punching method for remodeling construction, characterized in that a reaction bar (38) is penetrated and drawn out to the top.
delete In paragraph 7:
On both sides of the web 311 of the steel pile 31, sub-tension members 33' are further provided, which are non-adherently embedded in the interior of the concrete pile portion 32 and introduce prestress into the steel pile 31,
The upper part of the tension member 33 is fixed to the upper part of the concrete pile part 32 by the upper anchor part 35, and the lower part is fixed to the concrete pile part 36 by the lower anchor part 36 embedded in the inside of the concrete pile part 32. It is anchored in the lower part of the pile portion 32,
The upper part of the sub-tension member 33' is fixed to the upper part of the steel pile 31 by the upper sub anchorage 35' provided on the upper part of the reaction arm 38, and the lower part is fixed to the lower end of the steel pile 31. A horizontal partial back hammering method for remodeling construction, characterized in that it is anchored to the lower part of the steel pile (31) by a lower sub anchor (36') provided at the lower part of the fixed anchor (39).

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