JPH0978614A - Reverse striking method combined with leading cutting beam - Google Patents

Abstract

(57) [Abstract] [Problem] Since the wall thickness required as a retaining wall is not affected by the badness of the ground such as when the soft layer is thick, it is designed by the interval between the wall piles and the size of the lateral pressure distribution. It is very rational and economical, and it is possible to expect the same effect as improving the entire site simply by constructing a vertical plate-like ground undercut with the soil improved in front of the wall pile. , The construction is easy and rationalized, and the construction cost and the construction period can be shortened. SOLUTION: The wall piles 5 are constructed at a certain interval, the mountain retaining wall 4 of a length necessary for root cutting is constructed at the position of the main underground outer wall, and the true pillars 6 are constructed, and the front surface of the wall pile 5 is constructed. To the facing wall piles, the vertical plate-like pre-cutting beam 7 is constructed with the soil improved with soil cement, the first floor slab 2 is applied, and then the skeleton is shot down according to the progress of root cutting. After the root cutting is completed, the foundation beam slab is constructed on the preceding cutting beam 7 in the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse construction method for constructing an underground structure or an underground portion of a building, which is used in combination with a preceding cut beam.

[0002]

2. Description of the Related Art As is well known, the reverse striking method is one in which the main slab is used as a support work to strike down the skeleton according to the progress of root cutting. According to the method, as shown in FIG. 13, the lateral pressure acting on the mountain retaining wall 1 is a one-way vertical direction as a beam supported by the hard layer β that is the supporting layer at the upper part and the floor below the floor. The analysis method is adopted. This is the same as when using the general open-cut method. A is the root cutting side, B is the back side, and α is the soft layer.

[0003]

When the soft ground is deep, it is said that the above-mentioned upside-down construction method is more safe than the open cutting while applying the burrs by the assembled steel material.

In this reverse construction method, when the soft layer is thick, it is necessary to construct the cast-in-place concrete pile 3 for the structure column in the depth below the floor. In addition, the earth retaining wall 1 that will become the outer wall of the main building by hardening and shrinking of the slab concrete of the main building
A bending moment of M ₀ is generated at. Since M ₀ becomes very large, an underground continuous wall with a very large cross section is required to double as the main underground outer wall or the outer peripheral column, which is a big problem in terms of construction period and construction cost.

The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, and the wall thickness required as a mountain retaining wall is not affected by the poor ground such as when the soft layer is thick, and the interval between the wall piles and the lateral pressure distribution. It is very reasonable and economical because it is designed according to the size of, and it is only necessary to construct the ground pre-cutting with the ground improved with soil cement on the front surface of the wall pile,
It is intended to provide a reverse striking method with a leading beam which can be expected to have the same effect as improving the entire site, simplifying and rationalizing construction, as well as saving construction costs and shortening the construction period.

[0006]

In order to achieve the above-mentioned object, the present invention firstly constructs a wall pile at a pillar center position, and installs a mountain retaining wall of a length required for root cutting at a permanent underground outer wall position. We also constructed a true pillar and constructed a vertical plate-like ground undercut with a soil cement-improved ground on the front side of the wall pile facing the facing wall pile. After that, perform the reverse striking down of the skeleton according to the progress of root cutting, and after the root cutting is completed, build the foundation beam slab on the preceding cutting beam in the ground. Second, the mountain retaining wall is the basement underground. It is used as an outer wall, or the wall pile has T-shaped or cross-shaped protrusions on the left and right engaging parts of the mountain retaining wall, and the mountain retaining wall is temporary during the root cutting period. Is to be constructed as a post-strike wall using the engaging portion of the wall pile.

As shown in FIG. 12, when the soft layer is deep, a very large bending moment acts on the stress of the earth retaining wall caused by root cutting, and the earth retaining wall needs to have a high rigidity. According to the present invention as set forth in claim 1, since the preceding cutting beam serving as a virtual fulcrum is improved by soil cement to a position slightly below the floor mounting position, this becomes a plate-like preceding cutting beam, and it is as if the whole. It behaves like a hard layer.

FIG. 11 and FIG. 12 show such lateral pressure distribution and bending moment distribution of the mountain retaining wall. The bending moment distribution is as shown by the thick solid line, and the thin dotted line is the bending moment curve obtained by the general upsetting method. Compared with, the amount of deformation is also significantly reduced.

The preceding cut beam is divided at the position of the true column by the construction of the true column, and the function as the preceding beam is not sufficient. Therefore, it is considered that the ground strength is slightly lowered, or the rigidity as the cut is reduced, but the ability is not lost. Since cast-in-place concrete piles are installed below the final flooring position, it has sufficient strength and function as a leading beam, and even in the disadvantageous state that the virtual fulcrum is lowered, as shown by the dotted lines in Figs. 11 and 12. Safety is maintained by assuming a virtual fulcrum at the final floor mounting position.

If the structural column backfilling is sufficiently performed by using soil cement or the like, the preceding cut beam does not lose continuity, so that the bending moment distribution becomes more effective.

Even in the case of wall piles not fixed to the hard layer,
The bending moment generated in the retaining wall due to the lateral pressure acting on the retaining wall becomes like a simple beam with the wall pile position as the supporting point mainly in the horizontal plane. Therefore, it is possible to simply design by the interval between the wall piles without being much influenced by the depth of the soft layer and the strength of the ground. Therefore, the required depth of the retaining wall is 1-2m from the final root cutting bottom.
It is enough to reach a certain level, and it will be economically superior.

The present invention described in claim 2 is a case where the mountain retaining wall is used as a permanent underground outer wall, and the present invention described in claim 3 is a case where the mountain retaining wall is not used as a permanent underground outer wall. According to the present invention as set forth in claim 3, it is possible to provide a function as an earthquake-resistant wall by constructing the permanent underground wall as a post-strike wall by utilizing the shear key of the wall pile.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. 5 to 8 are side views of respective steps showing an embodiment of the reverse cutting combined use reverse precasting method of the present invention, and FIG. 1 is a longitudinal side view showing one embodiment of the prior cut beam combined reverse reverse injection construction method of the present invention. 2 is a plan view of the same as above.

As shown in FIG. 5, wall piles 5 which also serve as main installation pillars are constructed at a certain interval, and a mountain retaining wall 4 of a length required for root cutting is constructed at the main underground outer wall position. A cast-in-place concrete pile 3 for columns and a true column 6 are constructed. In addition, the lower end of the wall pile 5 does not need to have a length that reaches the hard layer β.

The wall pile 5 is constructed in a cross shape or a T-shape, and the engaging portions 5a are projected to the left and right to be integrally constructed on the mountain retaining wall 4. When both the mountain retaining wall 4 and the wall pile 5 are continuous walls, the mountain retaining wall 4 and the wall pile 5 are integrally constructed, and the wall pile 5 has a cross shape or a T-shape. As a matter of course, since the mountain retaining wall 4 is connected by the left and right engaging portions 5a, a joint method of horizontal lines is required. Further, either one or both of the mountain retaining wall 4 and the wall pile 5 may be made of precast concrete or steel.

As another embodiment, the wall pile 5 supports the mountain retaining wall 4 by overlapping the end of the mountain retaining wall 4 with the engaging portion as shown in FIG. In order to perform the connection in such a superposition manner, for example, a construction method which is inexpensive and sufficiently functions by superposition, for example, a construction method in which precast concrete is embedded in self-hardening mud water.

The earth retaining wall 4 may be used also as a permanent earth pressure wall or may be temporary. When the mountain retaining wall 4 is a temporary one, and when H, I-shaped steel or a precast type of superposition type is adopted, a cross key (or T-shaped) shear key of the wall pile 5 as a permanent underground outer wall It can be made to have a function as an earthquake-resistant wall by making it a post-casting wall.

The mountain retaining wall 4 constructed between the wall piles 5 has the same underground continuous wall construction method as the wall piles 5, and an element made by placing a concrete basket in a horizontally long drilling hole and placing concrete is preceded. , Connect by connecting in the subsequent line.

As another embodiment, the mountain retaining wall 4 is
Soil cement continuous wall shall be used. As an example, excavation is carried out using a large chain saw with a large excavator using bentonite solution and aeration, and after completion, cement paste (cement milk) is injected and mixed with stirring. , The so-called trender construction method is used.

As a continuous excavation method for the soil cement wall constituting the mountain retaining wall 4, in addition to such a trader method, a construction machine called a soil changer which is a small-sized 3-axis pile driving machine of the SMW method is used. A triaxial method may be adopted.

The earth retaining wall 4 reaches a minimum length capable of supporting the root cutting wall surface without collapsing, that is, reaches a position of about 1 to 2 m from the final root cutting bottom.
If there is a lot of groundwater, a waterproof membrane is installed below the retaining wall 4.

When there is a possibility that the strength required for constructing the earth retaining wall 4 with a soil cement continuous wall may be insufficient as described above, as shown in FIGS. 9 and 10, the self-hardening property injected into the excavation hole is shown. Before the muddy water (bentonite solution) or cement milk is kneaded and hardened, the web 10a
Is the horizontal direction and H or I is the main stress in the horizontal direction.
Shaped steels 10 of shaped steels are arranged in a comb-like shape by vertically arranging them with a hanging member such as a wire 11 at intervals.

The shaped steel 10 has circular or square holes 10b formed in the web 10a at appropriate intervals. Hole like this
By providing 10b, the material cost of the shaped steel 10 can be made low,
Further, when the shaped steel 10 is installed, the self-hardening muddy water (bentonite solution) or cement milk passes through the hole 10b, which improves the workability. It is also possible to install the shaped steel 10 at the stage of forming the drilled hole, and then inject self-hardening mud or cement milk and stir it.

As shown in FIG. 6, the groove that reaches the wall pile facing the front side of the wall pile 5 is drilled to a position deeper than the final flooring position while pouring an injection material such as cement milk and bentonite. A vertical plate-like ground undercut 7 is constructed by a continuous excavation method for cement walls. The construction of such a vertical plate-like undercut beam 7 shall be carried out with a continuous soil cement wall similar to the construction of the retaining wall 4, the trader construction method using a large chain saw with a large excavator, and the SMW.
It is possible to adopt a construction method in which a construction machine called a soil changer, which is a compact construction of the construction 3-axis pile driving machine, is used, and the construction is carried out by a triaxial construction method.

This vertical plate-shaped leading edge beam 7 reinforces the excavated groove bottom with a strength member such as RC, precast, or H steel when strength is required.

FIG. 4 is an overall plan view of the case where the ends of the mountain retaining wall 4 are superposed on the engaging portion to support the mountain retaining wall 4 as shown in FIG. Although it will be divided at the position of the true pillar 6 due to the construction of the true pillar, as mentioned above, although the rigidity as the cut-off is reduced, all of its capacity is not lost, and Since the cast-in-place concrete pile is installed underneath, it has sufficient strength and function as the preceding beam.
It should be noted that if the structural column backfilling is sufficiently performed using soil cement, the preceding cutting will not lose continuity,
A more effective bending moment distribution is obtained.

As shown in FIG. 7, root cutting is performed to the position of the first-floor slab 2 or to a depth such that it does not reach here.
After the first floor slab 2 is applied, the second root cutting, the construction of the basement first floor slab 12 (see Fig. 12), the third root cutting, etc. To do. The illustration of the basement floor on the way is omitted.

As shown in FIG. 8, a foundation beam slab 9 is built on the preceding cutting beam 7 in the ground after the completion of root cutting.

The cut-off axial force and the virtual fulcrum reaction force, which are reaction forces against the stress acting on the wall pile 5, are the same as those calculated by the general reverse striking method. In addition, since the wall pile 5 has a large bending rigidity and a large proof strength against deformation, it is possible to resist even if there is no burrs and the main body slab has a relatively large interval. This is very advantageous for speed of root cutting work and safe construction.

Although the mountain retaining wall 4 may be used as a permanent underground outer wall in some cases, it may be temporary. In that case, as shown in FIG. 4, the permanent underground outer wall 13 to be used as an earthquake-resistant wall is constructed again, but it may be constructed to be a post-strike wall by utilizing the engaging portion 5a of the wall pile 5.

Regarding the construction procedure, installation of wall piles,
Construction of structural columns, construction of earth retaining wall, construction of pre-cutting burrs in the ground are not limited to the description of the embodiment, and these can be performed simultaneously or any of them can be performed in advance, and others can be performed simultaneously or Depending on the situation of the site, it is possible to select it appropriately, for example, by performing the subsequent construction in which one of them precedes. One example is pre-boring for the installation of wall piles by drilling holes while pouring injection material such as self-hardening muddy water and cement milk by constructing a predecessor burial ground and a retaining wall with soil improved by soil cement. And so on.

[0032]

As described above, according to the reverse striking method for combined use of preceding cutting beams according to the present invention, the wall thickness required for the retaining wall is not affected by the poor ground such as when the soft layer is thick, and the wall pile is not affected. It is very rational and economical because it is designed by the interval of the space and the size of lateral pressure distribution, and only the vertical plate-like ground precut beam is installed on the front surface of the wall pile with the soil improved by soil cement. Therefore, the same effect as improving the entire site can be expected, and the ease and rationalization of construction, reduction of construction cost, and shortening of construction period can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing one embodiment of a reverse striking method with combined use of a leading flash of the present invention.

FIG. 2 is a plan view showing an embodiment of a reverse striking method with combined use of a leading flash according to the present invention.

FIG. 3 is a plan view showing another embodiment of the reverse striking method with combined leading flash of the present invention.

FIG. 4 is a plan view of the entire structure in the embodiment of FIG. 3 according to the reverse-cutting method with prior cutting flash of the present invention.

FIG. 5 is a vertical cross-sectional side view showing a first step in an embodiment of the reverse striking method with combined preceding flash of the present invention.

FIG. 6 is a vertical cross-sectional side view showing a second step in the first embodiment of the reverse striking combined reverse striking method of the present invention.

FIG. 7 is a vertical cross-sectional side view showing a third step in one embodiment of the method of reverse striking combined with reverse flashing according to the present invention.

FIG. 8 is a vertical cross-sectional side view showing a fourth step in one embodiment of the backward striking combined reverse-injection method of the present invention.

FIG. 9 is a cross-sectional plan view of an essential part showing an embodiment of a reverse striking method with combined use of a leading flash of the present invention.

FIG. 10 is a front view of the essential parts showing one embodiment of a reverse striking method with combined use of a leading flash according to the present invention.

FIG. 11 is an explanatory view showing a lateral pressure distribution and a bending moment distribution at the time of erection of the first floor slab by the reverse striking method with combined use of the preceding flash of the present invention.

FIG. 12 is an explanatory view showing a lateral pressure distribution and a bending moment distribution at the time of erection of a slab on the first basement floor by the reverse striking method with combined use of the preceding cut beam of the present invention.

FIG. 13 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

1 ... Mountain retaining wall 2 ... First floor slab 3 ... Cast-in-place concrete pile for structure pillar 4 ... Mountain retaining wall 5 ... Wall pile 5a ... Engagement part 6 ... Structure pillar 7 ... Preceding ground undercut 9 ... Foundation beam slab 10 … Section steel 10a… Web 10b… Hole 11… Wire 12… Basement 1st floor slab 13… Main basement outer wall

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[Procedure amendment]

[Submission date] October 14, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

As another embodiment, the mountain retaining wall 4 is
Soil cement continuous wall construction shall be used. As an example, excavation is carried out using a large chain saw with a large excavator using bentonite solution and aeration. After completion, cement paste (cement milk) is poured and mixed with stirring. Use the construction method.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

As a method for continuously excavating the soil cement wall which constitutes the mountain retaining wall 4, in addition to the method using such a large chainsaw, the in-situ soil mixing wall (SMW) method 3-axis pile driver can be made compact. A three-axis construction method using a construction machine called a soil changer may be adopted.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction contents]

As shown in FIG. 6, the groove that reaches the wall pile facing the front side of the wall pile 5 is drilled to a position deeper than the final flooring position while pouring an injection material such as cement milk and bentonite. A vertical plate-like ground undercut 7 is constructed by a continuous excavation method for cement walls. The construction of such a vertical plate-like pre-cutting beam 7 is to be carried out with a soil cement continuous wall as in the construction of the earth retaining wall 4, and a construction method with a large chain saw with a large excavator and an in-situ soil mixing wall. It is possible to adopt a construction method such as a construction method using a construction machine called a soil changer which is a miniaturized 3-axis pile driving machine of the body (SMW) construction method.

Claims (3)

[Claims] 1. A wall pile is constructed at a pillar center position, and a mountain retaining wall of a length necessary for root cutting is constructed at a main underground outer wall position, and
Constructing a true pillar, and constructing a vertical plate-like leading cut-out in the front of the wall pile with facing soil improved with soil cement, and applying the slab on the first floor, then constructing the skeleton A reverse striking method combined with pre-cutting, characterized by constructing a foundation beam slab on the pre-cutting undercut after completion of root cutting by performing reverse striking as the root cutting progresses. 2. The reverse striking method with combined pre-cutting according to claim 1, wherein the mountain retaining wall is used as a permanent underground outer wall. 3. The wall pile has protrusions on the left and right sides of the T-shape or cross-shaped engaging portions of the retaining wall, and the retaining wall is temporary during the root cutting period, and the main underground outer wall used for the earthquake resistant wall is the wall pile. 2. The reverse striking method with combined front cut-off according to claim 1, wherein the construction is performed as a post-strike wall by utilizing the engaging portion of.