JP2758319B2 - Embankment manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an embankment material used for a structure such as a road constructed on soft ground or an embankment for land preparation.

[0002]

2. Description of the Related Art Conventionally, earth, sand, gravel or crushed stone has been generally used as embankment material, and can be collected from natural mountains or rivers or crushed by rocks. Obtained by sieving.

However, the crushed stone described above involves not only dangerous work such as blasting a natural mountain with dynamite, for example, but also generating smoke during the blasting operation, and the working environment is not favorable. Also, although it is often thought that there is abundant resources, the extraction of soil, sand, gravel or crushed stone from a quarry is also a destruction of nature, and it will also reduce nature more and more.

[0004] In addition, when the above-mentioned soil, sand, gravel, or crushed stone is used as an embankment material for civil engineering structures in a soft ground area, the weight of the entire embankment material increases due to its large unit volume weight. There is a problem in that the civil engineering structure greatly sinks by pressing the soft ground.

Therefore, in order to avoid the above-mentioned problem, a molded article made of an expandable synthetic resin (generally referred to as a mold) is used as a lightweight embankment material that does not absorb water, that is, has a predetermined particle size. It is known to use it after cutting.

However, when the above-mentioned mold is used, it is used by being packed in a breathable or water-permeable tare so as not to be scattered by wind or the like or to be washed away by water due to its light weight. It is the present situation that a complicated process is forced. In this case, there is a problem that the bag is damaged and the crushed product inside the bag flows out. Further, the bag requires a considerable strength and is expensive.

On the other hand, as another measure for reducing the weight of the embankment material, it has been conventionally proposed to use a spherical clay foam sintered body having a diameter of about 3 mm to 10 mm as an embankment material, particularly in Europe. In such a clay foam sintered body, first, foaming clay is spheroidized by, for example, arranging foaming clay on a pan at a predetermined interval at a fixed interval and rotating the pan in a horizontal direction. It is created by foaming and firing in a kiln.

For this reason, the above-mentioned clay foam sintered body has a substantially spherical appearance, and has a bulk specific gravity corresponding to a unit volume weight of 0.3 to 0.6, which is about 2 compared to a bulk specific gravity of gravel of about 2. And very lightweight.

[0009]

However, in the above-described method for producing a clay foam sintered body, first, the expandable clay is kneaded with clay, water and a foaming material so as to have a certain viscosity. There is a step of obtaining the above, then there is a step of spheroidizing the above kneaded material in a pan, after that, since it is commercialized through the step of baking, the number of steps and the energy at the time of baking is greatly consuming However, there is a problem that the manufacturing cost is high.

[0010]

According to the present invention, there is provided a method for manufacturing an embankment material, in which two rotating rolls are provided in parallel with each other, and at least one outer periphery of each of the rolls is provided. A concave portion is formed on the surface, and a softened thermoplastic resin is supplied between the rotating rolls to obtain a connected body in which the molded body formed by the concave portion is connected by a thin portion, It is characterized in that the connecting body is cooled and divided from the thin portion.

[0011]

According to the above-mentioned method, the softened thermoplastic resin is continuously supplied between the rotating rolls to form a connected body in which the molded bodies are connected by a thin portion. The deformation of the molded body due to the natural fall of the molded body that has not been completely cured can be prevented, and the releasability of the molded body from the concave portion and the releasability of the thin portion from the roll due to the weight of the connected body can be prevented. Can be secured.

According to the above method, the embankment material, which is lighter than the conventional soil and sand, can be stably manufactured with good formability, and the firing step which has been required conventionally can be omitted.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In the method of manufacturing the embankment material, first, a used molded product made of various synthetic resins or foamed resins is crushed or reduced in volume and used as a raw material, and as shown in FIG. The above-mentioned raw materials are put into a supply hopper (not shown) of the single-shaft extruder 1, and the raw materials are supplied to the extruder 1.
Is heated and softened and melted by being fed into the barrel.

Subsequently, a molten thermoplastic resin 2 is extruded from a T-die 1a provided at one end of the extruder 1. The above-mentioned T-die 1a has, for example, a gap of one.
~ 20mm, preferably about 5mm, width is 20 ~ 100mm,
Preferably, the slit is about 60 mm.

On the other hand, below the T-die 1a, two substantially cylindrical rolls 3 and 4 are parallel to each other and substantially parallel to an installation surface (not shown). In addition, as shown in FIG. 3, a plurality of substantially triangular pyramid-shaped recesses 3a having a substantially triangular cross-sectional area gradually decreasing toward the bottom are provided on the outer peripheral surfaces of both rolls 3 and 4. They are provided so as to be adjacent to each other. FIG. 3 shows only one roll 3.

Therefore, as shown in FIG. 1, the outer peripheral surfaces of the rolls 3 and 4 are brought close to each other at a predetermined interval,
Further, the rolls 3 and 4 are rotated in opposite directions so as to send out the material sandwiched between them from above to below, and the thermoplastic resin 2 in the molten state is placed between the rolls 3 and 4 from above. Pour in.

At this time, by filling the recesses 3a and 4a while cooling the thermoplastic resin 2 between the rolls 3 and 4, the thermoplastic resin 2 is formed into a substantially hexahedral shaped body 5. It is continuously formed into a connecting body 7 connected by the thin portions 6.

Therefore, each of the rolls 3 and 4 has a cavity inside each of the rolls 3 and 4 so that the thermoplastic resin 2 can be cooled, and a temperature control medium passes through the cavity. Therefore, by adjusting the temperature of each of the rolls 3 and 4, the cooling state of the thermoplastic resin 2 can be made uniform.

In addition, since the molded bodies 5 are connected to each other by the thin portions 6, the individual molded bodies 5 are prevented from individually dropping naturally and are not hardened. Deformation due to falling of each molded body 5 is prevented.
Each molded body 5 connected by the own weight of the connecting body 7 has a concave portion 3a.
・ Each roller 3 can be easily peeled off from 4a.
4 and the releasability of the connector 7 from each of the recesses 3a and 4a can be improved.

Subsequently, the connecting member 7 suspended from the rollers 3 and 4 is cooled by cold air or the like, and the hardened connecting member 7 is divided from the thin portion 6 to separate the individual compacts. 5 ... is obtained.

For this purpose, a pair of substantially columnar dividing rolls 8 and 9 are provided below each of the rolls 3 and 4 in parallel with each other and at a predetermined interval. A rubber layer having a cushioning property is provided on the outer peripheral surface thereof.

Each of the splitting rolls 8 and 9 is rotated in opposite directions so as to entrain the connecting body 7,
In addition, if their peripheral speeds are different, that is, if the radii of the respective dividing rolls 8 and 9 are equal, their rotational speeds are different, or if their rotational speeds are equal, their radii are equal. Are set to be different.

From this, when each of the dividing rolls 8 and 9 is rotated with the connecting member 7 interposed therebetween, a shearing stress is applied to the connecting member 7, and the shearing force is applied to the thin portion 6 having a small strength. Then, the connecting body 7 is divided into each of the molded bodies 5 having a substantially hexahedral shape. Instead of the dividing rolls 8 and 9 described above, a Thomson blade may be embedded in one of the rolls.

Since the molded body 5 thus manufactured is extruded from the extruder 1 in a state where the thermoplastic resin 2 is almost melted, the specific gravity of the molded body 5 is 0.8 to true specific gravity.
1.3g / ml, 0.4-0.7g / ml in bulk specific gravity, which can be considerably reduced in weight compared to sand and gravel (bulk specific gravity 2.0g / ml). (Approximately 0.6 g / ml).

Further, in the conventional clay foamed sintered body, foamable clay is first spheroidized by, for example, arranging foamable clay on a pan by a predetermined amount at regular intervals and rotating the pan horizontally. Since it was made by foaming and firing in a kiln (firing kiln), the number of processes was large and the firing process was multi-energy consuming, so that the manufacturing time was prolonged and the manufacturing cost was high.

However, in the method of the above embodiment, the conventional firing step can be omitted, so that the manufacturing time can be shortened and the energy cost due to firing can be omitted, thereby reducing the cost. it can.

In the method of the above embodiment, the roll 3
4, the concave portions 3a and 4a are provided on both sides.
As shown in (1), the recess 3a may be formed only on one of the rolls 3, for example. At this time, the obtained molded body 5
Has a substantially tetrahedral shape as shown in FIG.

Next, a description will be given of an example of using each of the compacts 5 obtained by the above manufacturing method for an embankment structure. As shown in FIG. 5, the compact 5 is placed on the soft ground 10. It is used as an embankment material 12 to be filled in the embankment structure 11 when constructing a road or the like.

In such an embankment structure 11, as shown in FIG. 6, a water-permeable sheet 13 having water permeability is laid on the soft ground 10, and the embankment material 12 is stacked thereon.
A water-permeable sheet 13 is laid on the embankment material 12, and a concrete plate or an asphalt layer having a thickness of about 0.5 m, which is a basic structure for a normal road, is provided thereon as a surface layer 14 such as a road.

As shown in FIG. 5, both sides are covered with soil at an inclination of about 1: 2 and a thickness of about 0.5 m.
Although not shown, a drain pipe is provided on the side portion so that water that has entered the embankment material 12 can be quickly drained to the outside.

Thus, the embankment structure 11 such as a road on the soft ground 10 can be reduced in weight, and the settlement of the embankment structure 11 can be prevented.

Next, another example of using the molded bodies 5 obtained by the above-described manufacturing method as an embankment material 12 in an embankment structure, for example, in a case where a retaining wall is installed on soft ground. To explain, as shown in FIG. 7, embankment material 12 is piled up on soft ground 10 adjacent to sloping ground 15 to form surface layer 14 similar to the above, and retaining wall 16 is installed on surface layer 14. ing.

The embankment material 12 is filled between the retaining wall 16 and the sloping ground 15 as backing of the retaining wall 16. A surface layer portion 14 is formed on the backfilled embankment material 12 via a water-permeable sheet 13 in the same manner as described above, and the surface layer portion 14 can be used as a site.

Next, a construction method for installing the retaining wall 16 will be described. First, the retaining wall 16 of the soft ground 10 will be described.
The steel sheet pile 17 of 6 m in length is driven into both sides of 5.5 m in width at the construction position. The driving of the steel sheet pile 17 is set to, for example, 4 m in depth.

After driving the steel sheet pile 17 as described above,
The soft soil of the part partitioned by each steel sheet pile 17 was excavated to a depth of about 2 m and removed. Next, a water-permeable sheet 13 is laid on the excavated surface, and the embankment material 12 is piled on the water-permeable sheet 13 to flatten the surface.

Subsequently, a water-permeable sheet 13 was laid on the embankment material 12, and the above-mentioned surface portion 14 was formed thereon. On the surface layer portion 14, for example, a retaining wall formwork having a height of 5 m is assembled, and concrete is cast to construct the retaining wall 16 described above. On the other hand, a part of the sloping ground 15 was excavated to make a stable slope, and the earth pressure was set so as not to act on the back surface of the retaining wall 16.

Next, the embankment material 12 is piled up between the retaining wall 16 and the sloping ground 15 to flatten the surface. Thereafter, a water-permeable sheet 13 is laid on the embankment material 12, and the above-described surface layer portion 14 is formed thereon, or the topsoil is covered with soil, thereby completing the construction.

In such a retaining wall 16, the soft ground 10
However, since the embankment structure 11 is resistant to compression and has good drainage properties, the retaining wall 16 is stable without being displaced in the vertical and horizontal directions. Further, since the embankment material 12 is used for backing the retaining wall 16, almost no earth pressure is applied to the retaining wall 16. Therefore, the above construction method uses conventional sand,
Retaining wall 16 can be made thinner in the thickness direction than when gravel and soil are used for backfilling, and the need for foundation pile driving is eliminated.

As a result, for example, the top width is 0.5 m and the bottom width is
It is also possible to design a retaining wall with a height of 1.5 m, a height of 5 m, a wall gradient of 1: 0.1 and a dead weight of 12 t / m. When soil is used for backfilling, a top width of 1 m, a bottom width of 4 m and a wall gradient of about 0.3 are required, and the foundation pile is required to be placed on soft ground.

Next, each of the compacts 5 obtained by the above-described manufacturing method is used as an embankment material 12 for an embankment structure, for example, as shown in FIG. A description will be given of a usage example in which the embankment structure 11 is installed by the EPS (expanded polystyrene) block method. First, in order to stack the EPS blocks 18, the installation surface needs to be horizontal. When the soft ground 10 is inclined or provided with a concave portion,
Fill material 1 so that the installation surface of PS block 18 is horizontal.
Spread 2

As described above, in the above-described structure, the compact 5 used as the embankment material 12 has a substantially triangular pyramid shape having a convex portion on its surface. Can be surface contact or line contact.

In the past, since the clay foam sintered body used as the embankment material was substantially spherical, when used as the embankment material, the adjacent embankment material was in point contact, and the embankment layer formed by stacking the embankment material was used. Was not sufficiently compacted, resulting in insufficient strength and durability.

However, the configuration of the above embodiment is different from that of the contact between the adjacent embankment materials 12 and the embankment material 12 and the EPS.
Since the contact with the block 18 can be a surface contact or a line contact, the embankment is substantially spherical as in the prior art, so that the contact between the adjacent embankments becomes a point contact. As a result, a strong structure can be obtained, and the load can be dispersed, so that the compressive strength of the structures stacked on the molded body 5 can be increased. Therefore, the strength against the load can be improved.

The molded body 5 as described above has an appropriate specific gravity (0.8 to 1.3 g / ml in true specific gravity and 0.4 to 0.7 g / m in bulk specific gravity).
l), it can be prevented from being easily washed away by wind or water, and it is not necessary to pack the bag like a conventional crushed foam molded product. It is possible to plan.

In addition, when the compact 5 is used by filling it into a backfill material or the like in an embankment structure, the compact 5 has a polyhedral shape and also has burrs due to the remaining thin portion 6. , And does not flow as compared with the conventional substantially spherical clay foam sintered body, and is excellent in stability when stacked.

In order to further reduce the weight, a foaming material such as butane or pentane is mixed in the thermoplastic resin 2 in the extruder 1 so that the thermoplastic resin 2 is melted from the extruder 1 in a molten state. Is extruded, the thermoplastic resin 2 becomes 2
The foamed thermoplastic resin 2 becomes about 30 times larger, and a lighter molded body 5 of the thermoplastic resin 2 thus foamed can be obtained by using the rolls 3 and 4 and the dividing rolls 8 and 9 described above.

In the configuration and method of the above embodiment,
Although an example in which the concave portions 3a and 4a are provided in both the rolls 3 and 4 has been described, such a concave portion may be provided in only one of the roll rolls 3 as shown in FIG. In this case, the obtained molded body 5 has a substantially tetrahedral shape.

In the method of the above embodiment, an example was given in which the shape of the concave portion 3a was substantially triangular pyramid. However, the shape is not particularly limited as long as it has a convex portion on the surface and can be molded. However, for example, a polygonal pyramid shape such as a substantially quadrangular pyramid shape may be used. Good.

In the configuration and method of the above embodiment,
Although an example using a thermoplastic resin as a raw material has been described, there is no particular limitation as long as the bulk specific gravity is 1 or less and the moldability is excellent. For example, foamable clay and the like can be used.

[0050]

According to the method for manufacturing the embankment material of the present invention, as described above, two rotating rolls are provided in parallel with each other,
A concave portion is formed on at least one outer peripheral surface of each of the rolls, and the softened thermoplastic resin is supplied between the rotating rolls, and the molded body formed by the concave portion is connected at a thin portion. After the obtained connected body is obtained, the connected body is cooled and divided from the thin portion.

Therefore, according to the above method, the softened thermoplastic resin can be continuously supplied between the rotating rolls to produce an embankment material which is lighter than conventional soil and the like. Since the conventional firing step can be omitted, there is an effect that the manufacturing time can be reduced and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a method for manufacturing an embankment material of the present invention.

FIG. 2 is a perspective view of the embankment material.

FIG. 3 is a front view of a concave portion formed in a roll in the above-described manufacturing method.

FIG. 4 is a cross-sectional view of main parts of both rolls, showing that the concave portion is formed in one roll.

FIG. 5 is a schematic sectional view of an embankment structure using the embankment material.

FIG. 6 is a schematic sectional view of a principal part of the embankment structure.

FIG. 7 is a schematic sectional view of a retaining wall as another example of use of the embankment material.

FIG. 8 is a schematic sectional view of an embankment structure using the embankment material as a backfill material.

FIG. 9 is a perspective view showing a modification of the embankment material.

[Explanation of symbols]

 2 Thermoplastic resin 3 Roll 3a recess 4 Roll 4a recess 5 Molded body 6 Thin part 7 Linked body

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // B29C 59/04 B29C 59/04 Z (58) Fields investigated (Int.Cl. ⁶ , DB name) B29C 43/00- 43/58 B29C 69/00-69/02 B29C 59/02-59/04 B29D 31/00 E02D 17/00-17/20

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein two rotating rolls are provided in parallel with each other, and a concave portion is formed on at least one outer peripheral surface of each of the rolls. A method for producing a banking material, characterized in that after obtaining a connected body obtained by connecting the molded bodies formed by the recesses with thin portions, the connected body is cooled and divided from the thin portions. .