JPS6018769B2 - Construction method of underground structure - Google Patents

Description

[Detailed Description of the Invention] This invention integrates a pile driven into the ground and an underground continuous wall above the pile to retain the earth in the underground part of a structure and support the overburden load. This relates to a method of constructing an underground structure to be used as the main wall of the structure.

Conventionally, when using an underground continuous wall as a part of the main wall of a structure, methods have been explored such as using the lower part of the underground continuous wall itself as a support pile, but the depth of penetration into the supporting layer is insufficient. It must be sufficient, and it would be uneconomical to embed the wall, and the bottom surface must be as flat as possible to avoid stress concentration, and various other considerations are required.
This cannot necessarily be said to be rational.

This invention was developed in view of these circumstances, and to outline the construction procedure, first, an excavation hole is made in the column at the outer periphery of the structure, and a cast-in-place concrete pile is driven at the bottom of this excavation hole. The upper part is first backfilled with a material that is easy to excavate and does not fall off, such as soil cement or cement bacillus, to prevent collapse of the hole wall and to prepare for the subsequent construction of an underground wall of a predetermined thickness.

At this time, the pile cap should be approximately equal to or slightly above the flooring surface of the structure to be constructed. Next, the section of the underground wall supported by the concrete piles is excavated to the required depth and width using a clamshell or other ground rectangular excavator.

The concrete piles are filled with a consolidation retardant, and the pile heads and sides are excavated using a scraping device in order to integrate the piles with the underground wall. Next, using a partition steel plate with sheared reinforcing bars protruding from its surface, we repeat the pouring of reinforced concrete for each unit wall to construct a continuous underground wall.

At this time, bent reinforcing bars are placed in advance at positions corresponding to the pillars and beams of the structure body. Once the underground continuous wall is completed, gradually cut the roots inside the underground continuous wall to the flooring depth.

(This root cutting is done by changing the axial force of the cutting beam using a jack etc.
This is done in such a way that large bending stresses are not generated on the diaphragm wall. ) After excavating to a specified depth, the piles will be cleaned, pile caps will be treated, bent reinforcing bars will be erected, and cleaning will be carried out, followed by reinforcing of the structure itself and concrete IJ construction.

Next, the illustrated embodiment will be described. Figures 1 and 2 show the construction procedure for concrete pile 1. First, reinforcing bar cage 2 is inserted into the lower part of drilled hole A, and then concrete 3 whose setting time has been adjusted with a retarder etc. It is poured and the upper part is backfilled with soil cement or cement bacillus 4.

Note that the bottom of the concrete pile 1 is expanded as necessary (indicated by a broken line in the figure). Next, as shown in FIG. 3, excavation trench B is constructed. 7 in the figure shows the main body of the structure, and after the construction of the underground continuous leg 9, root cutting is performed, and the above-mentioned pile 1
It will be built on the backfilled area above. Figure 4 shows the construction procedure for the 9 parts of the underground continuous wall. First, an excavation groove B is created using an excavator 8, and a reinforcing bar cage 10 and shear reinforcing bars 13 that connect the unit walls are protruded from the surface. The underground continuous wall 9 is formed by repeating the insertion of the partition iron plate 12 and the pouring of the concrete 11.

FIG. 5 shows a 1-1 cross section at this time. Thereafter, the internal roots are cut as described above, and the structure body is constructed.

This invention has the above-mentioned configuration, and there is no need to use continuous walls as piles.Moreover, since piles have a sufficiently proven support mechanism, the depth of the underground continuous wall can be set to a depth that is temporarily required. It would be a good thing if there was one, and the structure would be more rational than using underground walls as piles.

In addition, since the concrete piles are installed at the bottom of the underground continuous wall, they do not get in the way during the construction of the underground continuous wall, allowing construction of a continuous underground wall that has a water-stopping effect.

Furthermore, since the inside of the drilled hole above the concrete pile is once backfilled with soil cement or other material that is easy to excavate, it is possible to prevent the hole wall from collapsing before and during the construction of the underground continuous wall, and it is easy to confirm the position of the pile. There is no problem with the construction of underground walls.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the concrete pile driving procedure, Figure 2
The figure is a cross-sectional view, Figure 3 is a plan view of the excavation trench of the underground continuous wall part, Figure 4 is a partial cross-sectional view showing the construction procedure of the underground continuous wall part, and Figure 5 is 1 of Figure 4. It is a sectional view corresponding to the −1 plane. A...Drilling hole, B...Drilling groove, C...Flooring surface, D...
...Bottom surface of underground continuous wall, E...Top surface of support layer, 1...
...Concrete pile, 2...Reinforced cage (pile), 3...
... Concrete (pile part), 4 ... Soil cement or cement bacillus, 5 ... Expanded bottom part, 6
...Guide wall, 7 ... Structure main column, 8 ... Excavator, 9 ... Underground continuous wall, 10 ... Reinforced cage (of underground continuous wall), 11...
・・・Concrete (underground part of the ship), 12...
・・Partition iron plate, 13 ・・・・・Sensing reinforcing bar. Figure 1 Figure 3 Figure 5 Figure 2 Figure 4

Claims (1)

[Scope of Claims] 1. An excavation hole is provided in a column at the outer periphery of the structure, a cast-in-place concrete pile is driven in the lower part of the excavation hole, and the upper part is backfilled with a material that is easy to excavate. A method of constructing an underground structure characterized by constructing an underground continuous wall of a required depth to be supported by an underground continuous wall, and then excavating the inside of the underground continuous wall to the flooring depth to construct the structure itself. 2. The method for constructing an underground structure according to claim 1, wherein the upper part of the concrete pile is backfilled with soil cement or cement bacillus.