JPH0255786A - Method of mixing earth and sand with fibrous material, soil conditioning method, and fiber used therein - Google Patents

Abstract

PURPOSE:To homogeneously mix a small amount of fibrous material with earth and sand by subjecting a specified fibrous material together with earth and sand to a centrifugal and vortex diffusion action. CONSTITUTION:0.05-2wt.% fibrous material comprising a monofilament, a multifilament, a tape yarn or a spun yarn, having a fineness of 50-200de and a length of 50-200mm is put into a Loedige mixer equipped with both a blade or shovel which rotates at a relatively slow speed (a peripheral speed of 1-15m/sec) for centrifugal diffusion or agitation of the earth and sand and a chopper which rotates at a high speed (a peripheral speed of 10-100m/sec) to form a vortex therein for diffusion and dispersion of the contents, so that mixing is effected by a centrifugal and vortex diffusion action.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for reinforcing and improving soil quality using fibers, and particularly provides a method for mixing fibers and soil for this purpose, and a fibrous material for this purpose.

<Conventional technology> Methods of reinforcing and stabilizing embankments and ground with natural materials such as wood and bamboo that have tensile strength have been known for a long time, and in recent years, methods of reinforcing and stabilizing embankments and ground with natural materials with tensile strength, such as wood and bamboo, have been known for a long time. Reinforced earthwork methods using so-called geotextiles such as woven and knitted fabrics, non-woven fabrics, nets, etc. in the form of bands, bags, etc., or synthetic resin nets, so-called polymer grids, have been developed and are widely applied.

All of these methods aim to reinforce the embankment etc. with a skeletal structure, and do not improve the soil quality or soil quality. Moreover, these reinforcing materials are expensive and require complicated manufacturing and processing such as weaving and weaving.

In addition, these reinforcement materials require special heavy equipment and a lot of work, and are arranged unevenly in the soil, so it is difficult to use the materials to achieve the same reinforced soil effect. must be used in large quantities, resulting in high costs.

By the way, Japanese Patent Application Laid-Open No. 55-167170 proposes a reinforced earth construction method in which continuous thread is mixed three-dimensionally into earth and sand to restrain it, but this method requires special construction machinery. However, it is difficult to efficiently and uniformly mix a large amount of soil and thread.

JP-A-57-100212 proposes reinforced soil in which short wire materials such as synthetic fibers are mixed with soil and sand, but in reality it is extremely difficult to uniformly mix short wire materials into soil and sand. However, this publication does not describe a specific method for mixing earth and sand and short wire rods. Furthermore, according to this publication, short wire rods are mixed at a high ratio of 3 to 20% by weight with respect to soil, but in some cases, the result is a fiber-rich structure, which is not good for improving soil quality or soil. It will be difficult.

(Problems to be Solved by the Invention) According to the research conducted by the present inventors, even if a short fiber material having a certain length is dispersed and mixed uniformly in soil, only a small amount It was found that soil quality could be improved and embankments and ground with a stable and highly reinforcing effect could be formed. However, it was extremely difficult to uniformly mix small amounts of short fibers into the earth and sand, so L% was used for civil engineering work. It is almost impossible to process large quantities of material.

The present invention solves the various problems of the prior art as described above, and provides an efficient and economical method for reinforcing and improving soil quality using fibers, a method for uniformly dispersing and mixing fibers and soil, and a method for uniformly dispersing and mixing fibers and soil to achieve the same. K aims to provide a stable embankment, a method for forming the ground, and a fiber material suitable for the same.

<Means for Solving the Problems> The present invention has a thickness of 50 to 2000 deniers and a length of 50 to 2
A method for mixing earth and sand and fiber material characterized by mixing the fiber material of 0.00 ■ and earth and sand using centrifugal diffusion or stirring action and eddy current diffusion or dispersion action, and a method of mixing fibrous material with a thickness of 50 to 2
The present invention relates to a soil improvement method characterized by mixing a fibrous material of 1,000 denier and a length of 50 to 200 mm with earth and sand by centrifugal/vortex diffusion action.

Furthermore, the present invention relates to an embankment and ground formation method characterized by using a material obtained by mixing a fibrous material with a thickness of 50 to 2000 deniers and a length of 50 to 200 denier and earth and sand by centrifugal/vortex diffusion action, Further, the present invention provides a fiber material for mixing soil and sand, which is suitable for these methods and is made of synthetic fiber monofilament, multifilament, tape yarn, or spun yarn and has a thickness of 50 to 2000 deniers and a length of 50 to 200 m.

The present inventors investigated the reinforcing effect on earth and sand, that is, the soil quality improvement effect, when cut fiber materials are uniformly dispersed and mixed into earth and sand such as mountain soil. We found that this is one of the most important factors. That is, although a reinforcing effect can be obtained even with fewer than 50 points, the degree of reinforcement is relatively small. This effect was especially clear for soil with low adhesive strength.

On the other hand, at more than 200 points, even if the length is longer than this, the reinforcing effect is the same or slightly different, and furthermore, the reinforcement is uniformly dispersed in the soil,
Mixing was expected to be extremely difficult.

For the above reasons, the length of the fiber material is 50 to 20
It was found that 0 ■ is effective and @70 to 150 ■ is a suitable range.

However, the fiber material having the above-mentioned length is not necessarily suitable from the viewpoint of uniform dispersion and mixing into the earth and sand.

The present inventors investigated a practical method for mixing cut fiber materials and earth and sand. First, when conventional general-purpose concrete mixers were used, the difference in specific gravity between the fibrous material and the earth and sand was too large, so the fibrous material was unevenly distributed above and on the side walls, or got entangled with the rotating body and was not evenly dispersed. , mixing was not possible. In this case, even if you mix and stir for a long time, -! The same result was obtained even with high-speed stirring. For this reason, we believe that it is impossible to evenly disperse and mix long-cut fiber materials and sand using a method that uses a normal mixer, and we believe that centrifugal diffusion, which can give three-dimensional flow to fibers and sand, is impossible. We focused on a mixer that has both vortex diffusion and vortex diffusion, and as a result of conducting mixing experiments, we surprisingly found that long-cut length fibers and soil could be evenly dispersed and mixed in a short period of time, such as a few minutes. I found it. In this case, even if a predetermined amount of long-cut fiber material is divided into parts or all at once into a mixer containing earth and sand, there is no significant difference in mixability. The decrease in tensile strength due to damage was slight, less than 10%.

Examples of such mixers are 1, for example, a blade or shovel that rotates at a relatively low speed to centrifugally diffuse or stir the soil, and a chopper (small size) that rotates at high speed to form a vortex inside the mixer to diffuse and disperse the contents. It is effective to use a rotary drum with stirring blades on the inner wall, or a chopper that rotates at high speed within a rotating drum that has stirring blades on its inner wall. A typical example is the Loedige mixer manufactured by Loedige.

Here, centrifugal diffusion means stirring and mixing the entire mixture in the mixer.
It is preferable to rotate at a relatively low speed in the range of 1 to 15 m/sec for blades, blades, etc. that are attached to the inner wall of shovels or rotating drums (speed of the maximum diameter of rotating bodies such as blades, shovels, etc.) that have dimensions approximately close to the diameter).〇 On the other hand, eddy current diffusion gives a high degree of dispersibility to the mixed materials, so specifically, it is 1/3 to 1/3 of the internal dimension (diameter) of the mixer
It is possible to use single-stage, multi-stage, or needle-like blades (hereinafter collectively referred to as choppers) with dimensions (diameter) of Also, it is preferable to rotate at a very high speed. Moreover, it is preferable and effective to provide a plurality of choppers, especially when mixing a large amount. The Lödeige mixer manufactured by Lödeige Co., Ltd. mentioned above satisfies the above conditions.

When using the above-mentioned mixing method, the soil and fiber material are repeatedly diffused and dispersed by the vortex action in the mixer, and are further mixed overall by the centrifugal diffusion action, thereby uniformly mixing both materials. However, if the cut length of the fibrous material is long, the fibrous material may become entangled with each other during mixing.
In addition to the so-called fiber ball shape, which cannot be uniformly dispersed and mixed, the reinforcing effect may be significantly reduced.

In order to avoid such inconveniences, the thickness of the fiber material used in the present invention (if the fiber material is a bundle, the thickness of the fiber material in the present invention means the thickness of the bundle) is a multifilament. In case of system.

For monofilament and tape yarn systems, the range is preferably from 50 to 1000 deniers. Mix the fibers.

When reinforcing soil and sand, if the fiber mixing ratio (wt%) is the same, the thinner the fiber, the greater the surface area of the fiber.
Along with this, the frictional force between the fibers and the earth and sand also decreases, and the reinforcing effect tends to increase.

If the thickness is below the above range, the fibrous materials will become entangled with each other, reducing the effect of uniformly dispersing and mixing with soil.If the thickness is above the above range, the fibrous materials will not be hard and will not be dispersed and mixed in a straight line. This creates the problem that the reinforcing effect decreases, and in order to compensate for this, it is necessary to increase the blending ratio of fibers.

The fiber materials used in the present invention include monofilaments, multifilaments, tape yarns, and spun yarns having the above lengths and thicknesses. these are,
Examples include synthetic fibers, recycled fibers, semi-synthetic fibers, inorganic fibers, and metal fibers. However, recycled fibers and semi-synthetic fibers are easily degraded and degraded by bacteria in soil and sand, while inorganic fibers such as glass fibers are Gold fibers are easily damaged when mixed with soil and sand, and gold fibers are susceptible to corrosion and corrosion in soil.
However, there are problems such as high cost. vinylon, polyester,
General-purpose synthetic fibers such as nylon, polyolefin, and polyacrylic fibers are most preferred because they do not have the drawbacks found in recycled fibers, semi-synthetic fibers, inorganic fibers, and metal fibers.

Fiber materials made of multifilaments may have a thick total denier, but the individual filaments may be thin and too soft, or the individual filaments may fall apart and become tangled fiber balls. ,
It is preferable to use a material that is partially focused by twisting or interlacing. In particular, it is recommended to use a conventional method of binding using a glue such as polyvinyl alcohol, acrylic, or starch because it is inexpensive and simple. The amount of solid content of the sizing agent applied to the fiber material is preferably within the range of 0.1 to 10 wt. If it is less than 0.1 inch, the above-mentioned problems tend to occur, and if it exceeds 10 inch, the fiber material becomes rigid, and although dispersion and mixing are possible, the reinforcing effect decreases. A more preferable range of glue adhesion is 1 to 6.
Wt %, which allows the earth and sand to be mixed uniformly with the fiber material, and furthermore, after mixing, the fibers locally break up and penetrate into the earth and sand more finely, increasing the reinforcing effect.

Such an increase in the reinforcing effect due to the dispersion of some of the single fibers of the fiber material after mixing may also be expected by using twisted or entangled multifilaments or spun yarns.

Further, as the tape yarn, it is also possible to use slit films, fabrics, etc.

Furthermore, the mixing ratio of the fiber material to the soil is 0.05 to 2.
It is preferable that the content be within the range of wt%. If it is less than 0.05wt%, the reinforcing effect is small, and if it exceeds 2wt%, a sufficient reinforcing effect can be obtained, but the fiber material becomes bulky, which not only makes uniform dispersion and mixing difficult, but also makes economical be disadvantageous to Preferably it is 0.05 to 1 wt%.

The soil that can be used in the present invention is not particularly limited and may be sandy soil. The moisture content contained in these soils and sands affects the mixability of the soils and fibers, so it is an important factor in obtaining the effects of the present invention, but the preferred range varies significantly depending on the type of soils. It cannot be specified uniformly. For example, in the case of mountain sand, if the moisture content is less than about 2 wt%, an appropriate three-dimensional flow state cannot be imparted to the fiber material and the earth and sand, resulting in poor mixability.

Also, depending on the type of soil, if the water content exceeds about 40 wt%, the fibrous material will become more entangled with the rotating blades, and the state of crushing the soil will deteriorate, preventing uniform dispersion and mixing. Furthermore, problems arise such as the power consumption of the mixer becomes significantly large.

The type of mixer may be a batch type or a continuous type.

In the case of a continuous mixer, a belt feeder is installed above the earth and sand input section to continuously feed long-cut fibers to a predetermined mixing ratio.

The mixing operation of the fibrous material and earth and sand in the present invention may be performed at the construction site or at a location away from the construction site, and may be determined based on convenience or economy in construction or transportation.

Since the mixture of fiber material and earth and sand in the present invention can be treated in the same way as ordinary earth and sand, the embankment and ground formation by K, such as transportation, leveling, and compaction, can be carried out in exactly the same manner as ordinary earthworks. Can be done.

In other words, transportation is performed by belt conveyors, dump trucks, bulldozers, and other transport machines, and leveling and compaction are carried out by backhoes and other shovel-type excavators, bulldozers and other transport machines, and rollers, tampers, and other compaction machines. It can be carried out.

Fields of application of the present invention include roads, railways, embankments, embankment structures such as residential land development, and ground reinforcement, but these are merely examples and are not necessarily limited to these fields.

<Effects of the Invention> According to the present invention, as described above, it is possible to uniformly disperse and mix a specific fiber material into the earth and sand by a special means, thereby changing the properties of the earth and sand and causing significant A reinforcing effect can be obtained.

Table 1 shows the dispersibility and mixability of various fiber materials and earth and sand, and the triaxial compression test results of the mixtures. The nine mixing machines used are Roedeige mixer FM manufactured by Roedege AG, Germany.
-130D type. Dispersibility and mixability were measured by mixing the fibers and soil, and then measuring the sieve content using the method (n=5). Dispersion/mixability was judged as O if the variation was within ±40% with respect to the calculated addition amount of fiber, and as poor in other cases.

In addition, a dispersion/mixing test was conducted using a soil mixer under the conditions of 240d/36f, 100sc* length, 3.5% sizing agent, 0.3cm blending ratio, and using mountain sand as shown in Table 1. The fiber material could hardly be dispersed or mixed visually.

As is clear from Table 1, a remarkable soil reinforcement effect can be obtained by dispersing and mixing a small amount of fibrous material into mountain sand.

The present invention will be explained below with reference to Examples, but these are not intended to limit the present invention.

<Example> A 100 wK length of vinylon thread (240 denier/36 filament 2 ment) was cut with 5 wt % of glue attached and bundled, and this was cut into the earth and sand used in the tests in Table 1 and the above-mentioned ray day. The mixture was evenly dispersed and mixed at 0.3 wt% using a Gemixer. We conducted a slope model experiment to compare this reinforced soil with the case of only earth and sand without the addition of fiber materials.

The Loedige mixer used in this example had a shovel with dimensions almost close to the internal dimensions of the mixer, and a single-stage blade with a diameter of about 115 times the internal dimensions of the mixer. Fi 4 m/sec was used as the circumferential speed, and 60 m/sec was used as the circumferential speed of the blade for vortex diffusion.

The slope model has a width of 2.0 m, a height of t, om, and a depth of 0.3 m.
It is an earthen tank made of a steel frame and an acrylic plate. As shown in Fig. 1, loading was carried out vertically and with the loading plate inclined at 25° from the horizontal (approximately perpendicular to the slope).

Figures 2 and 3 show the relationship between load and displacement.

With vertical loading, the yield point is reached at a displacement of 10 m, and with diagonal loading as shown in Figure 3, the yield point is reached at about 5 displacements, and then the deformation increases at about 70 to 90 inches of yield load, whereas in the case of reinforced soil, The load continues to increase even when the displacement is about 5u or more, and increases linearly when the displacement is about 10u or more.

The load at a displacement of 20 m (equivalent to a strain of about 5 -) is approximately twice as high in the vertical load and approximately three times as diagonally in the reinforced soil compared to the earth and sand alone. In addition, with only earth and sand, the displacement is approximately 10
A slip surface occurs in the reinforced soil, but no slip surface occurred within the experimental range in the reinforced soil.

A large reinforcing effect can be obtained by mixing a small amount of fibrous material with the earth and sand, and it is easier and more economical to implement than conventional reinforced soil methods.

Margin below

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the slope model used in the example, and FIGS. 2.3 are diagrams showing the relationship between load and slope displacement when the slope is made of reinforced soil and when it is made of only earth and sand. Patent applicant RiRashi Co., Ltd. Obayashi Corporation

Claims (1)

[Claims] 1) Thickness: 50 to 2000 denier, length: 50 to 200 m
A method for mixing earth and sand and fibrous material, characterized by mixing the fibrous material of m and earth and sand by centrifugal/vortex diffusion action. 2) Claim 1 in which the fiber material is composed of monofilament, multifilament, tape yarn, or spun yarn.
Method of mixing earth and sand with fiber materials as described in Section 1. 3) The method of mixing a fibrous material and earth and sand according to claim 1 or 2, wherein the fibrous material is a multifilament at least partially bundled by a glue, twist, or inter-fiber entanglement. 4) A method for mixing a fibrous material and earth and sand according to claim 1, 2, or 3, wherein the fibrous material is mixed in an amount of 0.05 to 2% by weight based on the earth and sand. 5) Thickness 50-2000 denier, length 50-200m
A method for improving soil quality characterized by mixing fibrous material of m and soil by centrifugal/vortex diffusion action. 6) Claim 5 in which the fiber material is composed of monofilament, multifilament, tape yarn, or spun yarn.
Soil improvement method described in section. 7) The method for improving soil quality according to claim 5 or 6, wherein the fibrous material is a multifilament at least partially bundled by glue, twist, or inter-fiber entanglement. 8) Claim 5, 6 or 7, in which the fiber material is mixed in an amount of 0.05 to 2% by weight based on the soil and sand.
Soil improvement method described in section. 9) Thickness 50-2000 denier, length 50-200m
An embankment and ground formation method characterized by using a material obtained by mixing a fiber material of m and earth and sand by centrifugal and eddy diffusion action. 10) The embankment and ground forming method according to claim 9, wherein the fiber material comprises monofilament, multifilament, tape yarn, or spun yarn. 11) The embankment and ground forming method according to claim 9 or 10, wherein the fibrous material is a multifilament at least partially bundled by glue, twisted yarn, or fiber entanglement. 12) The embankment and ground forming method according to claim 9, 10 or 11, wherein 0.05 to 2% by weight of the fiber material is mixed with the earth and sand. 13) Thickness 50-2000 denier, length 50-200
Fiber material for soil mixing consisting of synthetic fiber monofilament, tape yarn, and spun yarn. 14) Thickness 100-2000 denier, length 50-15
Made of 0mm synthetic fiber multifilament, glue,
A fibrous material for soil incorporation that is at least partially bound by twisting or inter-fiber entanglement.