JPH0347320A - Base structure by inverted placing method - Google Patents

Abstract

PURPOSE:To make formwork assembling, bar-arranging operation, and soil- discharging operation easier by a method in which a shore strut receiving earth pressure from sheathing wall is formed of steel frames packed with concrete, and the steel frame-concrete beam is used as the main beam. CONSTITUTION:A sheathing wall 1 such as continuous wall, sheet pile, etc., is formed in the surrounding, and a given number of structural straight columns 3 packed with concrete 7 are set in an excavating area 2 surrounded by the wall 1. The ground is excavated and in parallel with the excavation waling parts 4 and shore struts 5 packed with concrete 7 are orderly constructed from upper stair to lower stair. The columns 3 are joined with the struts 5 by integrally fixing paired gusset plates 8 to the corresponding positions of the columns 3 and also by connecting the plates 8 with the end of the strut 5 by bolts 9. Since the excavating space can be widened and also the lower excavated soil can be carried out effectively as well as the needs for formwork assembling and bar-arranging operation during excavation can be eliminated, the construction period can be shortened.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an underground inversion construction method.

(Problems to be solved by conventional technical inventions) In conventional underground excavation construction methods, a reverse construction method is sometimes adopted, in which construction of the underground section proceeds from the upper floor to the lower floor, contrary to the general practice. .

This construction method involves burying a predetermined number of structural pillars in an excavated area with retaining walls pre-formed around them, and then restoring the permanent steel-framed reinforced concrete columns, beams, and floors of the underground floor while receiving the load from the structural pillars. In parallel with the excavation, they are constructed sequentially from top to bottom.

However, in the case of the conventional reverse construction method, it is impossible to receive the earth pressure from the retaining wall using only steel columns and beams.
Or, it is necessary to make the cross section of the column or beam unnecessarily large, so excavation is necessary) t! .

Concrete for columns, beams, and floors must be poured. In order to perform this concrete work, the formwork and reinforcing work for columns, beams, and floors is complicated and time-consuming.Furthermore, since the floor concrete is poured, it is difficult to remove excavated soil from below. there were.

It is an object of the present invention to solve such conventional problems and provide an underground structure using the vine reverse construction method.

(Means for Solving the Problems) In order to achieve the above object, in the underground structure using the reverse pouring method according to the present invention, a steel frame material filled with concrete is used as a strut to receive earth pressure from a retaining wall. However, this steel-framed concrete beam is used as the main beam, and is characterized by a hanging structure.

(Example) Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

Figures 1 to 4 show one embodiment of the present invention, and as shown in Figure 1, in the underground reverse excavation method according to this embodiment, the construction procedure for the heap stop is the same as the conventional method. A retaining wall l such as a continuous wall or a sheet pile is formed in advance around the top retaining wall 1, and after burying a predetermined number of structural pillars 3 in the excavated part 2 surrounded by the upper retaining wall 1, earth and sand are excavated. , in parallel with the excavation work, the raising member 4. The struts 5 are constructed sequentially from the upper floor to the lower floor.

Here, the strut 5 according to this embodiment is formed of a steel frame material having a hollow part 6 inside as shown in FIG. After placing concrete 7 in the hollow part 6 at a predetermined position between the raised members 4, the cross section is set so that it can be used as a permanent steel concrete beam. Note that the strut 5 may be formed as a steel concrete beam in advance and then transported to the site.

In addition, as shown in Fig. 3, the main structure pillar 3 is also formed as a steel pipe concrete column with concrete 7 filled inside, instead of the usual single steel frame. The cross section has been set so that it can be used as a pillar.

As shown in FIG.
are fixed together, and the gusset plate 8 and the end of the strut 5 are joined with bolts 9. In addition, the third
In the figure, only the joint with the strut 5 in one direction is shown, and the joints with the strut 5 from the other three directions are omitted for convenience, but these joints also have the same configuration.

Further, the above-mentioned raised member 4 in this embodiment may be used as a permanent beam.

In this embodiment with such a configuration, the structural pillars 3 and struts 5, which were conventionally used only as temporary construction materials, are made of steel-framed concrete, and the cross-sectional design is designed so that they can be used as permanent columns and beams. Because of this structure, the earth pressure can be resisted only by these pillars and beams, and since they can stand at zero without forming concrete floor beams, the open space is large and the removal of excavated earth and sand from below is very efficient. I can do it well.

In addition, the conventional problem of complicated construction of formwork and reinforcing for beams and floors due to the reverse construction method is solved, and the excavation time is also shortened.

In addition to the above-mentioned embodiments, the cross-sectional configuration of the strut 5 can be appropriately changed as shown in FIG. 5, and the structural pillar 3 can also be configured as shown in FIG. As shown in the figure, a circular steel pipe or a 11-shaped steel can be used, and in this case, the connection with the strut 5 can be made as shown in the figure (e.g., it can be done according to the above embodiment, etc.). It goes without saying that the present invention is not limited to the examples, and that various modifications are possible without departing from the gist of the present invention.

(Effects of the Invention) The present invention is constructed as described above, and the steel concrete beams installed can be used as struts without placing floor concrete. Therefore, a large excavation space can be secured, and the excavated earth and sand below can be removed. Unloading can be carried out very efficiently.

Furthermore, since there is no need to construct formwork for beams and floors during excavation, or to arrange reinforcement, unlike in the past, the construction period can be shortened and complexity can be eliminated.

[Brief explanation of drawings]

Figures 1 to 4 show one embodiment of the present invention, Figure 1 is a conceptual diagram showing the configuration of a heap using the reverse construction method according to this embodiment, and Figure 2 is a cross-sectional diagram showing the configuration of the strut. Figure, Figure 3(a)
and Fig. 3(b) are explanatory diagrams showing the joints of the structural pillars and struts, Fig. 4 is a conceptual plan view of Fig. 1, and Fig. 5(a)
and FIG. 5(b) are sectional views showing other embodiments of the strut, and FIGS. 6(a) and 6(b) are explanatory views showing other embodiments of the structural pillar. . l... Earth retaining wall, 3... Structural pillar, 4... Raising material, 5... Strut beam, 6-... Hollow part, 7...
concrete. Engraving of the drawings Figure 1 Figure 6 Figure 6 (0) Figure Figure 6 (0) Figure 1 (b) 1 procedural amendment, y Indication of the case dated August 29, 1990 by the Director-General of the License Agency Igo 1999 patent Application No. 92368 Name of the invention Foundation structure by reverse construction method 3, Person making the amendment Relationship to the case Patent applicant address

Claims (1)

[Claims] This is an underground structure using the reverse pouring method, which is characterized by using the existing steel-framed concrete beams as struts.