JP2792968B2 - Self-supporting soil cement retaining wall and its construction method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a self-standing soil cement retaining wall and a method for constructing the same.

(Prior art) Conventionally, there has been known a method of forming a so-called soil-cement column by injecting a cement material such as cement milk into the ground to increase the bearing capacity of the soft ground, stirring and mixing with soil and sand. I have. The column R has water-stopping properties and can be constructed at low cost. In addition, in order to increase the resistance to bending moment due to the horizontal force acting on earth pressure, a reinforcing rod is inserted into the column on the tension side where earth pressure acts (in particular, As shown in FIGS. 7A and 7B, an H-section steel K or a sheet pile P is inserted in a column row R as shown in FIGS.

(Problems to be Solved by the Invention) The conventional column row in which a reinforcing bar is inserted on the tension side on which earth pressure acts is not sufficient against the bending moment due to the horizontal force. Even though the reinforcing effect can be enhanced, the column row to be reinforced has a drawback that the cost is higher than that of a reinforcing bar because a steel material or the like is used.

SUMMARY OF THE INVENTION An object of the present invention is to provide a column row having sufficient resistance to a bending moment and being able to construct a column at low cost.

(Means for Solving the Problems) A feature of the self-supporting soil cement retaining wall of the present invention is that a reinforcing steel core material is arranged in each position of a tension side where earth pressure acts and a compression side opposite thereto in a soil cement column. The reinforcing steel core portion at a position substantially coincident with the excavation surface is reinforced with a reinforcing bar. The tip of the lower end of the rebar core material may be bent upward. These rebars may be configured in a rebar cage in order to facilitate the installation of the rebar core material and the strap.

The feature of the construction method of the pillar row of the present invention is that, before the soil cement pillar row formed in the soft ground is solidified, each of the tension side where the earth pressure acts after the root is cut in the pillar row and the compression side opposite thereto. And a reinforcing bar that combines a reinforcing bar that is arranged at the position (1) and a reinforcing bar that reinforces the reinforcing bar portion at a position substantially coincident with the excavation surface. In order to facilitate the installation of the reinforced car, a steel-framed mounting jig is inserted in advance at the shaft center of the reinforced car, and before the reinforced cage is solidified by the mounting jig when the reinforced car is built. It may be constructed such that the building jig is built in the column, and after the building, only the mounting jig is pulled out from the column.

(Function) The tension side and compression side rebar core materials secure the fixing force between the rebar core material and the cement and resist horizontal earth pressure. Since the strap reinforces the reinforcing steel core material at a position substantially coincident with the excavated surface, it contributes to strengthening of the shearing force corresponding to the bending moment.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1 and FIG. 2, a reinforcing core material 2 as a reinforcing bar inserted in the axial direction in a soil cement column 1 is provided.
And the rebar core material 3 are arranged on both sides of the center line L, that is, on the tension side (the right side in FIG. 1) where the earth pressure acts in the direction of the arrow and on the compression side (the left side in the same figure) opposite thereto. It is. The lower ends 2a, 3a of the rebar cores 2, 3 have their tips bent upward in order to improve the resistance to tension due to horizontal earth pressure. Further, the reinforcing steel core material 2 and the reinforcing steel core material 3 are reinforced by winding the reinforcing steel core material portion at a position substantially coinciding with the excavation surface E around the band 4 as a reinforcing bar at a small pitch for a predetermined length.

As shown in FIGS. 3 and 4, the rebar core members 2 and 3 and the strap 4 constitute a rebar cage 6, and the rebar core members 2 and 3 are connected by connecting bars 5. A mounting jig 7 used for constructing the column 1 is inserted into the shaft center of the reinforcing bar 6.

The mounting jig 7 comprises an H-section steel 7a and a cylindrical base 7b fixed to the lower end thereof, and the base is formed at the lower end 2 of each of the reinforcing steel core members 2,3.
a, 3a, the upper part of which is reinforced by wire 8
I support it.

 Next, a method of constructing the column 1 will be described with reference to FIG.

Before the soil cement column 1 formed on the soft ground column is solidified as shown in FIG.
Insert

Since the reinforcing cage 6 is previously connected to the upper part of the building jig 7 by the wire 8, it is integrated with the building jig, and the vibration of the vibrator 9 is given to the reinforcing cage through the building jig. While building up to the specified depth.

When the reinforcing bar 6 reaches the position shown in FIG.
The insertion of the reinforcing bar cage is stopped, the wire 8 is removed, and the connection between the reinforcing bar and the building jig 7 is released.

Thereafter, as shown in FIG. 5 (c), while applying vibration to the building jig 7 by the vibrator 9, only the building jig is pulled out from the column 1 upward.

Referring to FIG. 6, an operation of integrating the reinforcing bar 6 and the building jig 7 prior to the construction of the column 1 will be described.

As shown in FIG.
Is installed in the ground at the construction site, and a reinforcing cage 6 is suspended by a crane and inserted into the casing as shown in FIG. Finally, as shown in FIG. 3 (C), the mounting jig 7 is inserted into the reinforcing cage 6, the two are connected by the wire 8, and the mounting jig 7 is chucked at the lower end of the vibrator 9. Then, the steel cage 6 and the mounting jig are integrated.

If a mixing and stirring device according to JP-B-58-29374 and JP-B-58-29375 is used as a device for constructing the soil cement column 1 in the soft ground, excavation can be performed smoothly, and cutting soil and filling material can be used. The efficiency of stirring is improved, and an efficient and high-quality column can be constructed.

(Effects of the Invention) According to the present invention, the reinforcing steel core material is arranged on the tension side and the compression side in the column of the soil cement and the band is further arranged, so that the fixing force with the cement is increased. In addition, sufficient resistance to bending moment can be obtained, and the column can be constructed at low cost. By bending the lower end of the reinforcing core material, the resistance to tension can be improved. The construction becomes easier by using a reinforced cage. In addition, when a reinforcing jig is used for the installation, a mounting jig can be used for quicker installation.

[Brief description of the drawings]

1 to 6 relate to the present invention, FIG. 1 is a sectional view showing a construction state, FIG. 2 is a perspective view of a column of a soil cement column, and FIG. Enlarged sectional view showing the part, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, FIG. 5 is a sectional view showing stepwise the construction process of the column, and FIG. 6 is a mounting jig and a reinforcing bar. And FIG. 7 is a plan view of a conventional pillar array. 1 ... Soil cement column, 2,3 ... Reinforcement core material, 2a, 3a ... Lower end of reinforcement core material, 4 ... Reinforcing bar (band bar), 6 ... Reinforcing cage, 7 ... Building jig , E ... Excavation surface.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichi Hibino 1-18-8 Tamami, Aso-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Morio Takahashi 3-7-1, Tsudanuma, Narashino City, Chiba Prefecture (72) Inventor Odaka Yutaka 2747 Notsuda, Machida-shi, Tokyo (56) References JP-A-2-204525 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 17/04 E02D 5/20 101

Claims (4)

(57) [Claims] 1. A reinforcing steel core is disposed at each of a tension side where soil pressure acts on a soil cement column and a compression side opposite thereto, and a reinforcing core part at a position substantially corresponding to an excavation surface is reinforced. Soil cement self-supporting retaining wall characterized by reinforcement with streaks. 2. The self-supporting soil cement retaining wall according to claim 1, wherein the lower end of the reinforcing steel core material is bent with its front end directed upward. 3. A reinforcing steel core material arranged at respective positions on a tension side where an earth pressure acts in the column and a compression side opposite thereto before the soil cement column formed in the soft ground is solidified. A method for constructing a self-supporting soil cement retaining wall, comprising: building a reinforcing bar cage in combination with a reinforcing bar for reinforcing the above-mentioned reinforcing bar core portion at a position substantially coincident with an excavation surface. 4. A reinforcing jig made of steel is inserted in advance in the shaft center of the rebar car, and when the rebar car is built, the rebar car is built by the mounting jig. 4. The method of claim 3, wherein only the jig is pulled out of the column.