JPS6360168B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an embankment construction method mainly used when constructing important structures or structures, and is applied to relatively large-scale embankments.

Prior Art Embankment construction has traditionally been a simple process of dividing the soil into many layers and compacting them. In this case, depending on the soil quality, the slope of the slope may need to be fairly gentle. Furthermore, if a large amount of rain falls soon after construction, ordinary embankments may be washed away, or the pore water pressure within the ground may increase, reducing internal shear resistance and causing sliding failure. In other words, the stability of the embankment is controlled by the shear strength of the compacted soil. The biggest weakness of these earth structures is that they have almost no tensile strength.

Various countermeasure construction methods have been studied for a long time to address the above problems, and partial solutions have been developed for each, and various construction methods are still being applied today.

For example, methods for stabilizing slopes include laying sheets on slopes to prevent direct rainwater, planting vegetation to protect slopes with their buds, stems, roots, etc., laying blocks and other slope stabilization methods, and installing pipes in the soil. There are reinforcement methods called reinforced soil, in which a material with tensile strength is placed inside the embankment, such as the drainage promotion method in which a highly permeable non-woven fabric is laid down, the Terre Alme construction method, and the early reinforced earth construction method.

However, these construction methods cannot solve all problems at once. Conventional countermeasure construction methods have only partially solved these problems, and each construction method still has many problems apart from its advantages.

Purpose of the Invention This invention was invented in order to solve the problems of the prior art described above, and is an embankment that can be expected to simultaneously take measures against drainage and reinforcement of insufficient shear strength at the beginning of construction, as well as protect and form the slope. The purpose is to provide a reinforcement method.

Structure of the Invention In the embankment construction method of the present invention, a powder solidified material such as cement material and sand are mixed in a dry state and then spread and laid, and groundwater, rainwater, and if necessary moisture from watering etc. are absorbed, thereby creating a porous soil. Forms a highly permeable ground reinforcement layer and slope wall.

The ground reinforcement layer is formed so as to be sandwiched between multiple embankment layers, and as mentioned above, the mixed powder solidified material and sand are spread and laid in a dry state, an unbonded cable is laid in the middle, and powder is added on top of that. Spread solidifying material and sand. Further, the thickness of each ground reinforcing material layer is, for example, about 100 mm to 300 mm.

The powder solidifying material made of cement material is a mixture of the powder solidifying material and sand after considering the grain size and composition, and is applied directly on site. This creates a water-permeable mortar.

In addition, for the glue wall, a similar mixture of powdered solidifying material and sand is spread and laid on the glue surface to a predetermined thickness to form a porous glue wall that is water permeable by absorbing moisture.

During construction, the aforementioned ground reinforcement layers and embankment layers are constructed alternately to complete the embankment at the planned height. On the other hand, for the slope surface, the embankment itself is set back to a position of, for example, 30 cm to 50 cm from the final slope surface, and powder solidified material and sand are spread and laid. In addition, during and after construction, the tension of the unbonded cable prevents deformation of the embankment layer and ground reinforcing material layer and corrects the shape of the slope. A strong embankment is completed.

Example The illustrated embodiment will be described below.

Figure 1 shows the structure of the embankment. The embankment is divided into multiple embankment layers A and the reinforcement layer B.
are provided alternately, and a glue wall C made of the same material as the reinforcing material layer B is formed on the glue surface portion.

Figures 2 to 6 show the construction process, and the work is carried out in the following steps.

(1) As shown in Figure 2, powder 1, which is a mixture of an appropriate amount of granular solidifying material and sand, is applied to the ground surface of the bottom where embankment is to be carried out, without kneading with water.
Spread about 50mm to 200mm.

(2) Lay the unbonded cable 2 as a tensile material on top of it. Anchors and other treatments are applied to this, and the 50~50~
Spread powder 1 about 100mm thick.

(3) A first layer of embankment is applied on top of this as shown in Figure 4 to form embankment layer A. The embankment material may be anything that can form an earthen structure, such as sand or loam. In addition, this embankment layer A itself should be set back approximately 30cm to 50cm from the final slope surface.

(4) Next, as shown in FIG. 5, the front net 3 for forming the final slope surface is attached together with the formwork 4.

(5) As shown in FIG. 6, the powder 1 used for the reinforcing material layer B is placed in the space between the front net 3 and the first embankment layer A.

(6) Similarly, repeat steps (1) to (5) to construct the second and higher layers to complete the embankment to the desired height shown in Figure 1.

In addition, during construction, unbonded cable 2
After construction, tensioning work can be performed to apply compressive force to the ground and to correct the shape of the slope. Figure 7 shows its structure.
is a sheath, and 6 is a fixed end. Furthermore, even after completion, if stress decreases or slope deformation occurs due to creep or ground movement, re-tensioning may become necessary. Therefore, as shown in FIGS. 8a and 8b, an oil cap 7 is attached to the anchor head to prevent damage due to corrosion or the like. In addition, as shown in FIG. 9, in order to make the sheath 5 fixed, mortar 8 may be injected into the sheath 5 to prevent corrosion of the steel in the sheath 5.

Effects of the invention Since the material with high water permeability quickly drains water inside the embankment and on the slope, it reduces the scouring caused by rainwater etc. in the early stages after construction is completed, which often occurs with ordinary embankments, and the pore water pressure inside the embankment. There is no collapse due to a decrease in internal shear strength due to the rise.

Because the mortar that forms the structure does not require adding water and kneading it with a mixer as in the conventional method, it is easy to work with, making it easier to transport materials, quality control, and construction, making it highly economical.

The mortar that forms the structure is solidified by underground water and rainwater, so it hardens at the optimal water-cement ratio of the solidifying material, allowing the material to exhibit its maximum strength.

Since the mortar that forms the structure is made of a material with high water permeability, there is no need for a device to drain water from behind, unlike traditional retaining walls. For example, there is no need for a water drain pipe or a drain sheet on the back. In this way, the mortar at the front protects, reinforces, and drains the slope.

By adding tensile material, it can sufficiently compensate for the lack of tensile strength, which is the biggest weakness of soil. For this,
The embankment will not only be able to withstand overload that cannot be supported by conventional embankments, but will also withstand earthquakes.
Since unbonded cables are used for this tensioning material, it is possible to prestress or retension the embankment, which increases the compressive force of the embankment and reduces settlement and deformation of the embankment due to overburden loads. This is because compressive force is added and the shear strength of the embankment increases.

By adding prestress to the tensile material, the shear strength of the embankment increases, and the amount of reinforcing steel material can be reduced, making construction easier and more economical. Furthermore, since compressive force is applied to the mortar of the reinforcing material layer, tensile cracks do not occur. Therefore, there is no separation of the permeable layer, allowing for smooth drainage.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing the structure of the embankment, Figure 2~
Fig. 6 is a longitudinal sectional view showing the construction procedure, Fig. 7 is a longitudinal sectional view of the tensile material using the unbonded cable, Fig. 8a is a longitudinal sectional view of the cap of the anchor head, and Fig. 8
Figure b is a perspective view of the cap, and Figure 9 is a longitudinal sectional view of the fixed tension member. A... Embankment layer, B... Reinforcement layer, C... Glue wall, 1... Powder, 2... Unbonded cable,
3...Front net, 4...Formwork, 5...Sheath,
6... fixed end, 7... cap, 8... mortar.

Claims (1)

[Scope of Claims] 1. A dry powder solidifying material in the form of granules and sand are mixed, spread and laid in layers to a predetermined thickness on site, and an unbonded cable for shear reinforcement is installed on top of that, and then A mixture of powder solidified material in the form of dry powder and sand is spread and laid in layers to a predetermined thickness to construct a ground reinforcement layer of a predetermined thickness, and an embankment layer formed by embanking earth and sand to a predetermined thickness and the ground. Reinforcing material layers are constructed alternately up to the planned height of the embankment, and on the slope surface, a mixture of dry solidified powder in the form of granules and sand, similar to the ground reinforcing material layer, is sprinkled to a predetermined thickness on the slope surface. They are laid and hardened by moisture penetration to form a permeable, porous ground reinforcement layer and a slope wall, and during and after construction, the tension of the unbonded cable strengthens the embankment layer and the ground reinforcement. An embankment construction method characterized by preventing deformation of the material layer and correcting the shape of the slope. 2. The embankment construction method according to claim 1, wherein the powder solidifying material is a cement material.