JPH0216817B2 - - Google Patents

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a method of constructing a retaining wall, and in particular, to a method for constructing a retaining wall in which the land required for construction is narrow and the stability of the retaining wall during and after construction. This article concerns how to construct a good retaining wall.

"Conventional technology" Generally, when building roads or other structures on sloped land, the sloped ground is excavated (cut down) and leveled. As a way to protect earthen walls from collapse, concrete retaining walls are installed to cover the earthen walls.

Conventionally, the method of constructing such a retaining wall is, for example, as shown in Fig. 14, after excavating the ground 1 at once from the line to the depth of the final level as shown by the solid line, Concrete frames 4 constituting the retaining wall 3 are placed at a distance from the earthen wall 2 in a stacked manner from the bottom, as shown from the solid line to the two-dot chain line in Figure 15.
A so-called sequential construction method is known in which the space between the earthen wall 2 and the retaining wall 3 is backfilled to the level indicated by the dashed-dotted line in FIG. 15 after all the concrete structures 4 have been placed.

``Problems to be solved by the invention'' However, in the above-mentioned sequential construction method, in order to prevent the earth wall 2 from collapsing during construction, the earth wall surface must be formed into a slope with a sufficient slope. However, only the amount that forms this slope, that is,
There is a drawback that the site for constructing the retaining wall 3 needs to be wide by the width indicated by the symbol W in FIG. 15.
In other words, if there is a residential lot or other existing structure near the site where the retaining wall 3 is planned to be constructed, and the land is limited, construction work becomes extremely difficult. and,
Problems like this are exacerbated as the ground becomes softer and the slope slope becomes gentler, and even if the ground is rocky, it becomes weathered and cannot stand on its own. When constructing the retaining wall 3, some kind of solution is required.

``Means for Solving the Problems'' In order to solve the above-mentioned problems, the present invention buries a support in the ground before excavation, and then excavates the ground including the support by a unit depth. In this method, the retaining wall is rolled backwards by placing a concrete frame covering the earthen wall using the exposed pillars as core material.

"Mannerism" According to the present invention, the upper part of the earthen wall is held down by the concrete frame during construction, and the weight of the concrete body is supported by the supports, so that the slope slope of the earthen wall can be made steeper. Can be done.

``Embodiment'' An embodiment of the present invention will be described below with reference to FIGS. 1 to 13. First, a borehole is drilled in the ground 1 to be excavated, and a support column ( For example, by erecting steel pipes (such as steel pipes) 5 and filling the gap between the pillars 5 and the borehole with mortar 6, multiple pillars 5 are buried vertically at intervals in the horizontal direction (direction that intersects with the plane of the paper). do.
Next, as shown in Fig. 2, (a) the ground 1 including the pillars 5 is excavated by a unit depth l shorter than the length of the pillars 5 to form a soil wall 7 having a vertical wall surface, and this soil A part of the support column 5 is exposed at a position facing the wall 7.

Next, as shown in FIG. 3, (b) a concrete frame 8 forming a part of the retaining wall is cast using the exposed pillars 5 as core materials, and the wall surface of the earthen wall 7 is covered with the concrete frame 8.

Then, once the concrete frame 8 has hardened, the same process as in step (a) above is performed again.
By excavating the ground 1 under the concrete frame 8 as shown in Fig. 4, and performing the same process as the step (b) above, new concrete is added under the concrete frame 8 as shown in Fig. 5. Pour the frame 8. By repeating steps (a) and (b) alternately in this way, a plurality of concrete frames 8 are successively connected from top to bottom, and finally a foundation is formed as shown in Figure 6. A retaining wall 9 is completed by pouring a wide concrete frame 8.

Here, to explain in detail the process (b), that is, the process of pouring the concrete frame 8, after the excavation work for the unit depth is completed as shown in Fig. 7,
As shown in the figure, a lock bolt (or earth anchor) 10 is embedded in the earth wall 7 in an almost horizontal state,
Mortar 6 is made to protrude from the wall surface and placed in the gap between it and the earthen wall 7.
Fill and fix. Next, as shown in Fig. 9, reinforcing bars 11 are placed in the vertical and horizontal directions (direction perpendicular to the page) below the previously cast concrete frame 8, and the vertical reinforcing bars 11 are placed under the previously cast concrete frame 8. Reinforcing bars 1 protruding from the lower surface of the frame 8
1 at the pressure contact portion 11a. Thereafter, as shown in FIG. 10, a formwork 12 is arranged between the earthen wall 7 and the pillar 5 and the reinforcing bars 11, and fixed to the lock bolt 10 using nuts 13. Next, as shown in Fig. 11, inside the formwork 12,
An amount of sand 1 that covers the bottom of the vertical reinforcing bars 11
4, and after leveling the top surface of the sand, concrete is poured into the formwork 12 and a concrete frame 8 is cast as shown in FIG. 12. When the formwork 12 is removed after the concrete has hardened, one unit of concrete frame 8 is completed as shown in FIG. 13. Note that the sand 14 is then
The ground 1 is further excavated and removed, and the lower part of the reinforcing bars 11 is exposed on the lower surface of the concrete frame 8.

In this way, in the present invention, since the excavation proceeds while pressing down the earth wall 7 from the excavation point,
The earth wall 7 does not collapse during construction. Furthermore, since the weight of the cast concrete frame 8 is supported by the supports 5, stability is good even when the ground beneath the concrete frame 8 is excavated. Therefore, the first
As shown in Figures 5 to 5, the ground 1 can be excavated with the earth wall 7 vertical, that is, with the slope slope at 90°.

By the way, as shown in Fig. 6, the entire structure consists of five concrete frames 8, and as a result of examining the stress state of the retaining wall 9 before placing the lowest concrete frame, which has the most severe load conditions, we found that The weight of each concrete frame 8 is lower than both the allowable supporting force of the column 5 and the allowable adhesive force between the column 5 and the concrete frame, and the axial stress generated in the column 5 is also lower than the allowable stress of the column 5. Ivy. Furthermore, regarding the stability upon completion, the investigation results showed that even when the supporting capacity of the rock bolts was ignored, a stable state could be ensured both at all times and during earthquakes.

"Effects of the Invention" As explained above, according to the present invention, a support is buried in the ground, and while excavating the ground containing the support in unit depths, the exposed support is used as a core material and a retaining wall is wound backwards. As a result, you can obtain the following excellent effects.

Since the earth wall surface can be formed vertically, the land required for constructing the retaining wall is small, and it is suitable as a method for constructing retaining walls when constructing structures on steep slopes, rocky ground, etc.

The amount of ground excavation is small, and there is no need for backfilling or other work.

Since the concrete frame is supported by the pillars, the stability of the retaining wall during and after construction is good, and safety during construction can be ensured.

[Brief explanation of drawings]

FIGS. 1 to 6 are vertical sectional views illustrating an embodiment of the present invention in the order of steps; FIGS. 7 to 13 are enlarged vertical sectional views illustrating an example of the concrete frame casting process of the present invention; FIGS. 14 and 15 are vertical sectional views illustrating a conventional retaining wall construction method. 1... Ground, 5... Support, 6... Mortar, 7
...Earth wall, 8...Concrete frame, 9...Retaining wall, 10...Rock bolt, 11...Reinforcing bar, 12
...Formwork, 14...Sand.

Claims (1)

[Claims] 1. In a method for constructing a retaining wall to protect an earthen wall formed by excavating the ground, after burying a support in the ground before excavation, (a) this A process of excavating the ground containing the pillars to a unit depth to expose a part of the pillars at a position facing the earthen wall, and (b) a process of pouring a concrete frame to cover the earthen walls using the exposed pillars as core material. A method for constructing a retaining wall, characterized in that the retaining wall is constructed sequentially from the top to the bottom, unit length by unit length, by repeating and alternately.