JPS63134716A - Reinforcing method for ground - Google Patents

Abstract

PURPOSE:To obtain improved land useful for preventing sliding or eroding, by mixing thread-formed extruded thermoplastic resin and earth with each other. CONSTITUTION:Fused thermoplastic resin 7 is extruded to be thread-formed through a nozzle 6, and is mixed with earth 10 for land for reinforcement. As a result, the movement of its earth is constrained, and so land can be prevented from sliding or being eroded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for reinforcing ground such as embankment ground, cut ground, or surface ground such as concrete.

[Problem that the invention seeks to solve]

Surface treatments for reinforcing the embankment or cut ground include adding soil and covering it with soil, protecting it with sheets or nets, or improving it with soil cement. However, there are problems with constructability and durability when using soil, nets and sheets are aesthetically pleasing, and fill cement does not allow for vegetation. When constructing an embankment, there are methods such as improving it with soil cement, reinforcing it by laying sheets, nets, or reinforcing bars in the embankment, or stabilizing it with retaining walls, as described above.
There are difficulties in economic efficiency and ease of construction on a small scale. Furthermore, a method of reinforcing soil particles by dispersing linear elements (threads) has been proposed (Japanese Unexamined Patent Publication No. 167170/1982). However, it has been pointed out that this method has disadvantages such as poor workability and inability to withstand erosion in the surface layer.

The purpose of this invention is to propose a method for reinforcing the ground, which eliminates the disadvantages of using nets, sheets, or linear elements as described above, and at the same time forms a stable layer of earth and sand on the surfaces of rock, concrete, etc.

[Means for solving problems]

This ground reinforcement method is characterized by continuously extruding a molten thermoplastic resin from a nozzle in the form of a thread, and then mixing it with the earth and sand of the ground to be reinforced. High density polyethylene, polypropylene, polyethylene terephthalate (polyester), polyamide (nylon)
etc. are preferable because they are excellent in terms of thermal stability, stringability, strength, durability, etc. These resins are usually heated and melted in an extruder and extruded from a nozzle.

Figures 1 (a), (b), and (c) are examples of an extruder used in the present invention, and this extruder 1 heats and kneads the polymer supplied into a hopper 2 in a cylinder 3 to melt it. It is guided to a T-die 5 via a nose 4 and extruded downward from a number of nozzles 6 bored at the tip. The extruded molten polymer 7 is continuous in the form of a thread, hangs down under its own weight, becomes thinner through some stretching, and then cools and solidifies to form a large number of parallel continuous threads 8.

This yarn 8 is mixed with earth and sand 10 sent from a belt conveyor 9 in a hopper 11, for example, as shown in FIG. 2, to form improved material ±12. The T-die 5 is provided with downwardly extending hoods 13, 13 on both sides to stabilize the molten polymer 7 extruded from the nozzle 6 and hanging down.

FIG. 3 shows another embodiment of the improvement ±12. In this example, earth and sand 10 is injected diagonally downward toward the molten polymer 7 which is extruded from the nozzle 6 of the long T-die 5 between the hoods 13 and 13 and is fused to the earth and sand 10 near the lower end of the hood 13. This is an improved version of ±12 consisting of threads 8, earth and sand 10, and the threads 8 fused thereto.

In addition, in the figure, 14 is the earth and sand injection port, and 15 is the hood 13.
This is an air vent that blows temperature-controlled air inside.

The improvement ±12 described above can also be made with the apparatus shown in FIG. This device consists of a horizontal circular gouer 5' and a rotating disk 16 provided concentrically below the circular gouer 5'. Earth and sand 1 rotates at high speed around the shaft 17 and is sent out to the upper surface of the disk 16 via the inside of the shaft 17.
0 to the outside of the disk 16 by centrifugal force. The molten polymer 7 extruded from the nozzle 6 and hanging down comes into contact with the earth and sand 10 discharged to the outside of the disk below and fuses with the earth and sand 1.
Improved soil is made of a mixture of 0 and the threads 8 fused thereto.

To stabilize the ground on surfaces such as concrete and bedrock,
As shown in FIG. 5, molten polymer 7 is extruded from T-die 5 onto the surface of concrete layer 18, and before being cooled and solidified, it is brought into contact with concrete layer 18 and fused, and at the same time earth and sand 1o is fed from belt conveyor 9. This is continuously carried out on the surface of the concrete layer 18 to form an improved layer of ±12 consisting of threads 8 and earth and sand 10 fused to the surface of the concrete layer 18. This improved ±12 layer may be repeatedly formed into two or more layers. Alternatively, the threads 8 may be fused to each other at the points of contact between the upper and lower layers, or the molten polymer 7 may be injected with earth and sand to bring them into contact, and the threads 7 and the earth and sand 10 may be fused.

When the T-die 5 of the extruder is reciprocated and moved in the width direction by a predetermined width in the length direction, the threads 8 are continuously bent into a waveform to form a sheet as shown in FIG. When the width of the reciprocating movement is increased, the adjacent threads 8 overlap and when brought into contact in the state of the molten polymer 7, they are fused together and the threads 8 become net-like.

Further, as shown in Fig. 7, two T-dies 5.5 are provided in parallel, and while reciprocating in opposite directions, they are moved in the width direction to fuse the threads 8 to form a net shape. I can do it.

As shown in FIG. 8, relatively short hoods 13 are attached to the lower side of both sides of the T-die 5 to prevent the molten polymer 7 immediately after being extruded from the nozzle 6 from coming into direct contact with the outside air. can stabilize the formation of Furthermore, food 13
Attaching long mantles 19, 19 parallel to both outer sides of the hood 13 and forming an air layer 20 with an open bottom end between the hood 13 and the cooling and solidifying conditions of the molten polymer 7 or the thickness of the yarn 8, This is suitable for adjusting stretching conditions and the like.

That is, when air is sent from above to below within the air layer 20 and its temperature is raised to a high temperature, cooling and solidification are delayed.
This can be promoted at low temperatures.

In addition, by making the air flow high speed, the yarn 8 is pulled downward or the lower end of the mantle is narrowed as shown in FIG. By increasing the drawing ratio of , it is possible to create yarn 8 with fine fineness. The physical properties of the yarn 8 are primarily affected by extrusion conditions such as the properties of the polymer, the extrusion speed of the extruder, and the temperature. For example, the thickness of the yarn 8 largely depends on the extrusion speed (for example, kg/Hr) at which the polymer is extruded from the extruder, but as mentioned above, the fineness depends on the conditions such as cooling, solidification, traction, and stretching after extrusion. control, control of fusion, etc. can be achieved.

In this way, the cooling and solidification conditions can be controlled, so that the fusion of the earth and sand 10 and the thread 8 during mixing with earth and sand in Fig. 2.3.4, and the fusion of the thread 8 and the concrete layer 18, the earth and sand in Fig. 5, can be controlled. 10 or between the yarns 8 and 8 in FIG. 6.7 can be controlled.

This reinforcing method will be explained below with reference to illustrated embodiments.

Figure 9 shows the embankment 22 formed on the slope of the second earthwork.

This embankment 22 is reinforced by mixing polypropylene threads 8, and the surface layer 23 is reinforced by mixing relatively fine threads 8 into the layers to prevent erosion of the surface layer due to wind and rain, etc. The middle layer 24 is reinforced by mixing threads 8 with a thicker yarn than the surface layer to prevent the entire embankment from slipping.

Note that the lower layer portion 25 is a layer that is not reinforced.

FIG. 10 also shows an example in which the embankment 22 on the slope of the ground 21 is reinforced. This embankment 22 has a net-like thread 26 formed by the method shown in Fig. 6 arranged on the surface layer 23 to prevent erosion of the surface layer, and an improved ±12 mixed with thread 8 is arranged on the middle layer 24 to prevent slippage. This is an example of prevention and reinforcement.

Fig. 11 shows that a molten polymer is extruded and fused onto the surface of a rock 27 on a steep slope using the method shown in Fig. 5 to form threads 8, and at the same time, earth and sand 10 are mixed to create an improvement ±12, which is fixed to the surface of the bedrock 27. The surface ground was reinforced by installing improved ±12.

(Actions and Effects of the Invention) This invention has the above configuration. In this reinforcing method, the extruded molten polymer becomes threads and is mixed with earth and sand to form improved soil. The threads control the movement of earth and sand. It acts as a restraint and prevents slipping and erosion.

The yarn is formed by melting and extruding polymer using an extruder at the construction site, so compared to simply mixing the yarn and earth and sand, the degree of adhesion to the earth and sand or the base surface, net form, etc.
It is possible to control the formation of sheet-like threads or adjust the thread thickness, and the technology has a wide range of applications, and can be applied to ground reinforcement in a wide range of target fields, such as raw mountains, rock masses, and concrete surfaces.

In addition, in this method, the polymer is melt-extruded into yarn using an extruder or the like at the construction site, so a large amount of low-cost yarn can be supplied, reducing material costs and improving construction efficiency.

[Brief explanation of the drawing]

Figures 1 (a), (b), and (c) are a side view, front view, and plan view of the T-die of the extruder used in this reinforcement method, and Figures 2.3.4 and 2.3.4 show the mixing of yarn and sand, respectively. Fig. 5 is a side view of the state in which the improved soil is created, and Fig. 5 is a cross-sectional view of the state in which the improved soil is fused to the surface of the concrete layer to form the improved soil layer. Fig. 6.7
Figures (a) and (b) are schematic diagrams of the reciprocating motion of the T-die and the resulting sheet-like and net-like yarns, respectively. Figure 8 is a cross-sectional view of the T-die with the hood and mantle attached, and Figure 9 , 10 and 11 are cross-sectional views of the embankment on the mountain slope and the rock surface ground, respectively, reinforced by this reinforcement method. ■... Extruder, 2... Hopper, 3... Cylinder, 4... North, 5... T-die, 6... Nozzle, 7...? Melting polymer, 8... Yarn, 9... Belt conveyor, 10... Earth and sand, 11... Hopper,
12... Improved soil, 13... Hood, 14... Sediment injection port, 15... Air port, 16... Rotating disk,
17... Axis, 18... Concrete layer, 19...
Cloak, 20...air layer, 21...earth, 22...
Embankment, 23...surface layer, 24...middle layer, 25...
・Lower layer, 26...Net-like thread, 27...Bedrock. Figure 3 Figure 41A Figure 5

Claims (1)

[Claims] (1) A ground reinforcement method characterized by continuously extruding a molten thermoplastic resin from a nozzle in the form of a thread, and subsequently mixing it with earth and sand of the ground to be reinforced.