JPH04194227A - Earth reinforcing method with tubular reinforcement - Google Patents

Abstract

PURPOSE:To provide a reinforcing member having immediate effect with excellent workability by fixing the basic end part of a reinforcing member on the natural ground after penetrating the tubular member into natural ground, expanding the extreme end part of the member in the radial direction to introduce prestress. CONSTITUTION:A reinforcing pipe 4 of tubular member is horizontally or a little upward facingly provided on the slope of a natural ground 2, and the part 8 of the basic end part is connected and fixed with a surface protection member 12. The diameter expanding part 6 of the extreme end is expanded in the direction making a line square with the pipe 4, the ground around the pipe 4 between the expanding part 6 and the connecting and fixing part 8 is compressed, the natural ground 2 and the pipe 4 are made into one body by friction resistance of the pipe 4 and bearing pressure resistance of the expanding part 6 to form a strong pseudo retaining wall. A circumferential groove is formed on the extreme end member 30 of the pipe 4, a screw is provided on the circumferential face of head part, threadedly engaged with thread on the extreme end of a steel bar 34, the member 30 is lantern-likely expanded by tension to introduce prestress to the pipe 4. Hereby, directly after providing the pipe 4, natural ground and the reinforcing member are integrated into one body to exhibit a reinforcing function.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a reinforced earthwork method, and in particular, when reinforcing the ground for slope stabilization, a method using a tubular reinforcing material in which small-diameter pipes are installed in the ground as a reinforcing material is used. Regarding reinforced earth construction methods.

[Conventional technology]

Among the reinforced earthwork methods, there are two types of methods for installing reinforcing materials to reinforce natural ground: the pre-boring method and the direct driving method. The pre-boring method involves inserting reinforcing material after drilling a hole in the ground, and then injecting grout to bond the reinforcing material to the entire surface. In the direct casting method, a method is often used in which the reinforcing material is cast into the ground, then grout is injected through a hollow hole and the entire surface is bonded.

These methods use grout to integrate the reinforcing material and the ground, so it takes several days to integrate the reinforcing material and the ground.

Moreover, such reinforcing materials will only have a reinforcing effect after the ground is deformed.

[Problem to be solved by the invention]

However, in the construction procedure of this type of reinforced earthwork method, each step is usually constructed one after another, and the next step of excavation is carried out after the installed reinforcement material is integrated with the ground. There was a problem in that the number of days required for the grout to harden after installing the reinforcing material was about 7 days with ordinary cement, and 3 days even with early strength cement.

The purpose of the present invention has been made to solve the above-mentioned problems, and uses a tubular reinforcing material that integrates the ground and the reinforcing material immediately after the reinforcing material is installed, and effectively and effectively exerts the reinforcing function. The purpose is to provide a reinforced earth construction method.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a reinforced earthwork method using a tubular reinforcing material in which a tubular reinforcing material is directly cast into the ground. The reinforcing member is fixed to the slope of the ground, and prestress is introduced into the reinforcing material.

After penetrating the reinforcing material into the ground, the base end of the reinforcing material is fixed to the slope of the ground, and then the diameter of the distal end of the reinforcing material is expanded in the outer circumferential direction. This is characterized by the introduction of prestress.

[Effect]

According to the above configuration, the prestress introduced into the tubular reinforcing material allows the ground and the tubular reinforcing material to be more firmly integrated. When the diameter of the distal end of the reinforcing tube is expanded, such prestress is introduced between the connecting and fixing portion at the rear end of the reinforcing material and the protruding portion whose diameter has been expanded. Due to this effect,
The ground in between becomes stronger due to the restraining force, making it possible to suppress deformation. By casting a plurality of such tubular reinforcing materials, a strong pseudo-retaining wall can be constructed in the ground due to the frictional resistance of the reinforcing material surface and the bearing pressure resistance of the enlarged diameter portion.

〔Example〕

Hereinafter, some embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is for explaining the construction method of this embodiment, in which reinforcing pipes 4, which are tubular reinforcing materials, are driven horizontally or slightly upward into the slope created by successively cutting down the ground 2, using the direct driving method. Set up By driving the reinforcing pipe 4, the connecting and fixing part 8 at the proximal end is connected and fixed to the surface protection work 12 that has been constructed in advance.

After that, the diameter of the enlarged diameter portion at the tip is enlarged. The expanded diameter portion 6 is the reinforcing tube 4
By expanding the diameter in a direction perpendicular to the diameter, the ground on the pipe peripheral surface between the expanded diameter part 6 and the connecting fixing part 8 is compressed, and a tensile force is generated in the reinforcing pipe 4, so that the ground and the reinforcing pipe become more become closer,
Due to the frictional resistance of the reinforcing pipe 4 and the bearing pressure resistance of the enlarged diameter part 6,
The earth 2 and the reinforcing pipe 4 are integrated. Such reinforcement pipe 4
A strong pseudo-retaining wall is created by pouring the walls vertically, horizontally, and horizontally.

FIG. 2 is for explaining the procedure for driving the reinforcing pipe 4 by the direct driving method.

As shown in FIG. 2(A), after a surface protection work 12 has been previously constructed on the slope of the ground, an impact type excavator 24 is installed at the rear of the reinforcing pipe 4.
connect and penetrate the ground by blowing. A connecting plate 18 and a taper washer 20 are interposed between the reinforcing pipe 4 and the surface protection work 12, and an air hammer that does not require a reaction force connected to a compressor 26 is used as the impact type cutting machine 24.

When the reinforcing pipe 4 is finished being cast, the reinforcing pipe 4 and the surface protection work 12 are connected and fixed by the connecting fixing part 8, as shown in FIG. 2(B).

Next, as shown in FIG. 2(C), when the expanded diameter portion 6 at the tip of the reinforcing tube 4 is expanded, the tube outer periphery of the expanded diameter portion 6 protrudes in a direction perpendicular to the axial direction of the reinforcing tube 4. Therefore, a tensile force acts in the axial direction on the reinforcing pipe 4 whose root is fixed, and the reinforcing pipe 4 is fixed with a compressive force acting on the ground around the pipe.

FIG. 3 shows details of the enlarged diameter portion 6 at the tip of the reinforcing tube 4 used in this example. As shown in FIG. is formed, and a slit (not shown) is formed in the longitudinal direction of the pipe.
A screw 32 is cut on the inner peripheral surface of the head. FIG. 3(B) shows a state in which the tip member 3o protrudes in the circumferential direction, and can be expanded in diameter into a lantern shape by engaging the screw at the tip of the steel bar 34 with the screw 32 and pulling it.

In this way, prestress is introduced into the reinforcing pipe when the diameter of the tip of the reinforcing pipe is expanded. occurs in As a result of this action, the ground between them receives a restraining force and becomes stronger, making it possible to suppress deformation.

Incidentally, the tip of a reinforcing tube with a length of 3 m and an outer diameter of 48.6 mm is
Expanding the outer diameter to 150 mm will compress the ground by about 30 m, and when we conducted a casting experiment on sandy ground with an N value of about 10, it was confirmed that a prestress of about 1 was introduced. Ta.

Figure 5 shows the experimental results of this example, where the reinforcing material casting length was 3.0 m, the casting ground was N=8 fine sand, and the pre-boring method, direct driving method, and direct driving method were used. Experiments were conducted using three methods: the method of this embodiment, which has a diameter enlargement at the tip, and the method of this embodiment.

In the pre-boring method, a hole is drilled using an electric auger (diameter φ = 48 mm), and after grout is injected into the hole, reinforcing bars are inserted to serve as reinforcement (finished diameter φ = 50 mm).
mm).

In the direct driving method, a reinforcing tube (φ=48.6 mm) is driven using an impact type cutting machine.

In this embodiment method, in addition to the direct driving method, the tip of the reinforcing tube is expanded in diameter (expanded diameter φ=148 mm).

As a result of the experiment, as shown in the figure, the peripheral surface friction resistance of the reinforcing material is 8 tf/rrr or less in the direct driving method, which does not exceed the standard value, and even in the pre-boring method, it is at most 10 tf/rrr.
/ m. On the other hand, according to the method of this embodiment, from around 10 t f /rrI to 11.7 t f
/ m, and it became clear that the frictional resistance increased significantly compared to the other two methods.

Expanding the diameter of the tip is done to ensure the integration of the reinforcing pipe with the ground, and other than the method of expanding the diameter into a lantern shape by pulling the tip as in this example. Then, as shown in FIG. 4, the wedge 38 is struck from the rear of the inner pipe 36 provided with the slit to expand the inner pipe 36.
It is also possible to enlarge the diameter of the tip portion in which the slit (not shown) is formed.

FIG. 6 shows an example of the reinforcing pipe 4 used in this embodiment, which is composed of a perforated part 14 and a steel pipe part 16, and has an enlarged diameter part 6 at the tip.
, is provided with a connecting fixing part 8 at the base end. The perforated part 14 is provided to drain water that seeps into the ground and stabilize the ground, and in this example, a plurality of reinforcing bars are arranged in a circular manner in the longitudinal direction,
Wrap the wire around it and fix it with a small gap between the wires.

The gap is made into a slit hole. The unevenness of the outer peripheral surface caused by the wound wire rod has the effect of increasing the frictional resistance in the longitudinal direction of the reinforcing tube. Of course, a perforated steel pipe with drainage holes scattered in the pipe wall may also be used. When using reinforcing pipes with drainage effects, it is suitable for growing plants if green protection works are constructed on the slopes of the ground.

FIG. 7 shows the connecting and fixing part 8 at the base of the reinforcing pipe. A flange 22 is formed at the base end of the rust pipe portion 16, and is tightly fixed to the earth via a taper washer 20 and a connecting plate 18.

In this way, as a method for integrating the ground and reinforcing material with a quick-acting reinforcing material installation method that does not involve grouting,
By using the direct driving method, expanding the diameter of the tip of the tubular reinforcing material, and applying prestress to the tubular reinforcing material, the reinforcing effect can be increased and it can be more firmly integrated with the ground.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to install reinforcing materials with immediate effect, and it is possible to provide a reinforced earth construction method with excellent workability.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram showing the construction procedure of this embodiment, and Fig. 3 is a cross-sectional view of essential parts showing an example of the reinforcing material used in this embodiment. , FIG. 4 is a cross-sectional view of the main part showing another example of the reinforcing material, FIG. 5 is a diagram showing experimental data showing the effect of this example, and FIG. 6 is a diagram of the reinforcing material used in this example. The side view and FIG. 7 are explanatory diagrams showing a method of fixing the reinforcing material used in this example.

Claims (1)

[Claims] 1. In a reinforced earthwork method using a tubular reinforcing material in which a tubular reinforcing material is directly cast into the ground, after the reinforcing material is penetrated into the ground, the base end of the reinforcing material is inserted into the ground. A reinforced earthwork method using a tubular reinforcing material, which is fixed to a mountain slope and is characterized by introducing prestress into the reinforcing material. 2. In the reinforced earthwork method using tubular reinforcing materials in which tubular reinforcing materials are directly cast into the ground, after the reinforcing material has penetrated into the ground, the base end of the reinforcing material is fixed to the slope of the ground. A reinforced earthwork method using a tubular reinforcing material, characterized in that prestress is introduced into the reinforcing material by subsequently expanding the diameter of the tip end of the reinforcing material in the outer circumferential direction. 3. The reinforced earthwork method using a tubular reinforcing material according to claim 2, wherein the diameter of the tip of the reinforcing material is expanded by pulling the tip. 4. The reinforced earth construction method according to claim 2, wherein the tip of the reinforcing material is provided with an inner pipe having a groove in the longitudinal direction, and is expanded by hitting a wedge from the rear of the inner pipe, A reinforced earthwork method using a tubular reinforcing material, characterized by expanding the diameter of the tip. 5. The reinforced earthwork method according to claim 1 or 2, characterized in that a surface protection work is previously constructed on the slope of the ground, and the base end of the reinforcing material is fixed to the surface protection work. Reinforced earth construction method using materials. 6. A reinforced earthwork method using a tubular reinforcing material according to claim 1 or 2, wherein the reinforcing material has water holes. 7. In the reinforced earthwork method according to claim 1 or 2, a greening protection work is constructed in advance on the slope of the ground, the base end of the reinforcing material is fixed to the greening protection work, and the reinforcing material is A reinforced earthwork method using tubular reinforcing materials that are characterized by having water holes. 8. A reinforced earth construction method using tubular reinforcing materials, in which the reinforced earth construction method according to any one of claims 1 to 7 is sequentially applied each time a ground is cut down. 9. A tubular reinforcing material used in the reinforced earth construction method according to any one of claims 1 to 8.