JP2948468B2 - Ground improvement pile preparation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement material made of sand, gravel, crushed stone, slag, etc., which is put into a casing penetrating into soft ground, and the ground improvement inside the casing is pulled out. The present invention relates to a ground improvement pile device for discharging a material into a ground from a lower end of a casing to form a ground improvement pile.

[0002]

2. Description of the Related Art In this type of ground improvement pile forming apparatus, a casing is penetrated to a predetermined depth in the ground by using an exciter or the like, and a ground improvement material is injected into the casing from a hopper at an upper end portion of the casing. Then, by pulling out the casing, the ground improvement material inside the casing flows down due to its own weight and is discharged from the lower end of the casing into the ground, forming a ground improvement pile in the ground.

[0003] In a conventional soil improvement pile forming apparatus, a steel pipe (steel pipe for general structure) is used as a casing, but such a steel pipe generally has poor surface slipperiness, and sand or the like adheres thereto. Due to its ease, the flowability of the ground improvement material when the casing is pulled out is poor, which causes clogging inside the casing, lowering the workability and forming a good ground improvement pile in the ground. In addition, the inner surface of the steel pipe is easily rubbed by sand or the like when the ground improvement material is introduced into the casing or when the casing is pulled out, and rust is easily generated therewith, so that the above-mentioned fluid dischargeability is further deteriorated, and the casing is worn away. There is a problem that he hasten.

[0004] In this type of soil improvement pile forming apparatus,
In general, after the ground improvement pile is put into the casing, compressed air is supplied from above the inside of the casing to pull out the casing, and the inside of the casing is pressurized. I try to raise it. In this case, the pressure inside the casing is 5
If the pressure is as high as ~ 6 kgf / cm ² , the flowability of the soil improvement material is certainly improved, but when a very soft part is locally present in the ground into which the casing has penetrated, the ground improvement material is discharged from the casing. The soil improvement material forming the pile is swelled in the lateral direction in the relevant part, and the diameter and the pressure density become extremely uneven in the length direction of the pile, which causes a problem that a high quality soil improvement pile cannot be formed. .

The present invention has been made in view of the above-mentioned problems in the conventional apparatus, and has good flowability and dischargeability of the ground improvement material when the casing is pulled out, so that a high quality ground improvement pile can be efficiently formed in the ground, It is an object of the present invention to provide a ground improvement pile forming device capable of significantly improving durability.

[0006]

According to the first aspect of the present invention, a ground improvement material S is put into a casing 1 penetrating into the ground, and the ground improvement material inside the casing 1 is pulled out while the casing 1 is pulled out. S is discharged into the ground and the ground improvement pile P
In soil improvement pile reclamation apparatus adapted to construct a, the first inner peripheral surface casing, about the average molecular weight to have a desired thickness 10
It is characterized in that a sliding layer 4 made of a plate material of not less than 100,000 polyethylene is formed.

According to a second aspect of the present invention, a plurality of through holes 5 are provided in the casing at appropriate intervals, and an anchor portion 6 made of the same material as that of the polymer material plate is integrally formed in each of the through holes 5. It is characterized by becoming.

[0008]

According to the first aspect, after the casing 1 has penetrated into the ground to a predetermined depth, the casing 1 is pulled out, so that the ground improvement material S put into the casing 1 is removed.
Due to its own weight and the surface lubrication effect of the sliding layer 4 formed on the inner peripheral surface of the casing 1, the fluid flows down lightly without remaining on the inner peripheral surface side of the casing 1 or clogging on the way. It is continuously discharged from the lower end of the casing 1 into the ground without interruption, thereby forming a high quality ground improvement pile P having a uniform diameter and pressure density over the entire length and a good drainage property.

The sliding layer 4 covers and protects the inner peripheral surface of the casing 1 to prevent the casing 1 from being worn and corroded.
Also, in the present invention, a polymer material having a required thickness
Is attached along the inner peripheral surface of the casing 1.
Thus, the sliding layer 4 can be easily formed.

[0010] Further, since the sliding layer 4 is made of polyethylene having an average molecular weight of about 1,000,000 or more, the sliding layer 4 has excellent surface lubricating property and extremely excellent flowability of the ground improvement material. It is possible to improve the durability of the casing 1 by remarkably improving the durability of the casing 1 and to improve the wear resistance, impact resistance and chemical resistance of the sliding layer 4 itself. It is possible to maintain good surface lubrication without being easily worn or corroded.

According to the second aspect, when the sliding layer 4 is formed by attaching a plate made of a polymer material along the inner peripheral surface of the casing 1, the sliding layer 4 is fixed to the casing 1 by the anchor portion 6. And is not integrally peeled off from the casing 1.

[0012]

Embodiments will be described with reference to the drawings.
FIG. 1 shows a ground improvement pile forming apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a cylindrical casing provided with a hopper 2 on an upper portion, and a vertical vibration of a vibration generator 3 provided at an upper end thereof. It penetrates into the ground by the action. A sliding layer 4 made of a polymer material is formed on the inner peripheral surface of the casing 1. Note that this device is suspended by an elevating operation wire (not shown) suspended from the top of a reader (not shown).

The sliding layer 4 is made of a so-called ultra-high molecular weight polyethylene having an average molecular weight of about 1,000,000 or more.
Extremely excellent surface slip, impact resistance, abrasion resistance, and chemical resistance (corrosion resistance). The sliding layer 4 is formed by sticking a plate material of the required thickness made of the ultrahigh molecular weight polyethylene along the inner peripheral surface of the casing 1.

In order to form the sliding layer 4, a plate made of the ultrahigh molecular weight polyethylene having a required length, width and thickness is rolled into a cylindrical shape which can be fitted in the casing 1, and this is formed into a casing 1 It can be formed by inserting it into the inside and attaching it along the inner peripheral surface of the casing 1. As the plate made of ultrahigh molecular weight polyethylene, a commercially available plate can be used. In this case, for example, a material known as Somalite, which is a registered trademark of Somar Industries, Ltd., is preferable. This ultra high molecular weight polyethylene of somalite has an average molecular weight of about 2,000,000 or more, and has particularly excellent properties in slipperiness, non-adhesion, abrasion resistance and chemical resistance.

In this case, the cylindrical plate made of ultra-high molecular weight polyethylene is easily separated from the inner circumferential surface of the casing 1 simply by being made to follow the inner circumferential surface of the casing 1. Prior to insertion into the casing 1, a plurality of through holes 5 having, for example, a wedge-shaped cross section are provided in the casing 1 at predetermined intervals as shown in FIG. After that, a chip (small piece) of the same material as the ultrahigh molecular weight polyethylene plate is inserted into each through-hole 5 and the chip is heated by a burner or the like, so that the chip is melted in the through-hole 5, As shown in FIG. 2, an anchor portion 6 integrated with the cylindrical plate material inserted into the casing 1 is formed, and the sliding layer 4 is fixed to the inner peripheral surface of the casing 1 by the anchor portion 6. It can be.

A flame is sprayed into the through hole 5 provided in the casing 1 by a burner or the like without using the above-mentioned chips, and the surface of the sliding layer 4 facing the through hole 5 is melted. An anchor portion having the same function as the anchor portion 6 can also be formed by engaging the surface fusion portion with the inner peripheral wall portion of the through hole 5. It is to be noted that, even though the casing 1 is not provided with the through-hole 5 in the casing 1 and the anchor portion 6 is formed in the casing 1, the ultra-high-molecular-weight polyethylene plate material rolled into a cylindrical shape can be attached to the casing 1 via an adhesive. May be adhered to the inner peripheral surface of the base.

As shown in FIGS. 1 and 2, steel stopper rings 7 are provided at upper and lower ends of the inner peripheral surface of the casing 1.
Are fixed by welding so as to be in contact with the upper and lower end surfaces of the sliding layer 4 made of the ultrahigh molecular weight polyethylene plate material, and the stopper ring 7 prevents the sliding layer 4 from coming out of the casing 1.

In forming the sliding layer 4 from the ultrahigh molecular weight polyethylene plate material, one plate material may be used and adhered along the entire inner peripheral surface of the casing 1. If the diameter and length of the casing 1 are relatively large and there is no large-size commercially available product that can attach the inner peripheral surface of the casing 1 with one sheet, a plurality of small-sized plate members are appropriately used. What is necessary is just to add and attach to the inner peripheral surface of the casing 1. As shown in FIG. 1, a hopper 2 is provided at the upper end of the casing 1 and the base end of the hopper 2 is opened. .

In FIG. 1, reference numeral 9 denotes an on-off valve provided inside the hopper 2, which is normally held in a closed position as shown by a solid line, for example, by a spring (not shown). When the improving material is supplied and flows down into the hopper 2, it is opened by the flow pressure. Reference numeral 10 denotes an air supply nozzle for supplying compressed air into the casing 1 when the on-off valve 9 is closed.

In using the ground improvement pile forming apparatus having the above-described configuration, first, the exciter 3 is operated while the apparatus is suspended from the top of the reader with a wire for raising and lowering operation. While oscillating the casing 1 up and down,
The casing 1 is penetrated into the ground while the wire for raising and lowering operation is being paid out. When the casing 1 reaches a predetermined depth into the ground, the operation of the vibration exciter is stopped, and a ground improvement material S made of, for example, sand is injected into the casing 1 from the hopper 2 in a required amount. The casing 1
The ground improvement material S may be charged into the casing 1 when the casing 1 penetrates into the ground.

Thus, the ground improvement material S
Is supplied, compressed air is supplied by the air supply nozzle 10, and while the inside of the casing 1 is pressurized to about 1 kgf / cm ² , the casing 1 is pulled out while winding up and down the operation wire. Then, the ground improvement material S inside the casing 1 is discharged from the lower end into the ground to form a ground improvement pile (sand pile) P. At this time, the ground improvement material S inside the casing 1 is urged by its own weight and the pressing action by the pressurized air, and in particular, by the excellent surface lubrication effect of the sliding layer 4 formed on the inner peripheral surface of the casing 1, It flows down very lightly without adhering and remaining on the peripheral surface or clogging in the middle, and is continuously and continuously discharged from the lower end of the casing 1 into the ground, so that the diameter is uniform over the entire length and moderate. A soil improvement pile (sand pile) P of good quality with good drainability, which is compacted, is efficiently formed in a short time.

Further, in this case, since the inside of the casing 1 is maintained at a low pressure of about 1 kgf / cm ² , even if a very soft part locally exists in the ground into which the casing 1 has penetrated, There is no possibility that the ground improvement material S extruded from the lower end of the casing 1 to form the pile will swell in the relevant portion, and therefore, the ground improvement pile P having a uniform diameter and pressure density over the entire length can be formed. .

In this soil improvement pile forming apparatus, the sliding layer 4 formed on the inner peripheral surface of the casing 1 has an average molecular weight of about 1
Since it is made of a so-called ultra-high molecular weight polyethylene of more than 100,000, its excellent surface lubricating effect makes it possible to improve the flowability of the ground improvement material S at the time of pulling out the casing as described above, while the sliding layer 4 Casing 1
The inner peripheral surface of the casing 1 can be covered and protected to improve the durability of the casing 1, and the sliding layer 4 itself is easily worn out due to its excellent wear resistance, impact resistance and chemical resistance. Since it does not corrode or corrode, it can be used for a long time while maintaining good surface lubricity.

FIG. 3 shows an apparatus 11 for testing the surface lubricity of the sliding layer 4, that is, the slipperiness. FIG. 4 shows the results of the test performed by the apparatus 11. In this test apparatus 11, a rocking table 13 is pivotally mounted on a base 12 so that the tilt angle can be adjusted. Three types of test plates A, B, and C for forming a sliding layer are sequentially placed on the rocking table 13. Put on. Thus, the ground improvement material sample 14 (in this case, sand) whose moisture has been adjusted is filled in a short cylindrical pipe 15 and the bottom of the filled sand 15 is t (2) from the lower end of the pipe 15.
mm), the ground improvement material sample 14 (sand) slides down when the rocking table 13 is gradually inclined from the horizontal state by placing it on each of the test plates A, B, and C so as to be in close contact with each other. Measure the angle θ. Here, among the test plates A to C, A is SS41 (carbon steel plate for general structure), B is
SUS304 (stainless steel plate) and C are plate materials of ultra-high molecular weight polyethylene (registered trademark Somalite).

Referring to the test results in FIG. 4, the point common to all of the three test plates A to C is that the smaller the moisture content of the soil improvement material sample 14 (sand), the smaller the angle at which it starts to slip, and hence the slippage. It turns out that the nature is good. The minimum sliding start angle of the test plate A is about 25 degrees, the test plate B is about 15 degrees, and the test plate C is about 10 degrees. Therefore, the test results show that the test plate C, that is, the plate material of ultra-high molecular weight polyethylene (registered trademark Somalite) has the best sliding property.

[0026]

According to the first aspect of the present invention, since the sliding layer made of a polymer material is formed on the inner peripheral surface of the casing, the ground improving material inside the casing is removed when the casing is pulled out. Due to the surface lubricating effect, it flows down lightly without adhering and remaining on the inner peripheral surface side of the casing or clogging on the way, and is continuously discharged from the lower end of the casing into the ground without interruption, and therefore over the entire length. It is possible to form a high-quality ground improvement pile having a uniform diameter and compaction density and good drainability, and to improve workability. When the inside of the casing is pressurized, the ground improvement material can be sufficiently discharged at a low pressure of about 1 kgf / cm ² . Furthermore, since the inner peripheral surface of the casing is covered and protected by the sliding layer, wear and corrosion of the casing can be prevented, and the durability of the casing can be improved.

According to the present invention, since the sliding layer is formed by attaching a polymer material plate having a required thickness along the inner peripheral surface of the casing, a commercially available polymer material plate is used. It can be used, and the sliding layer can be formed easily and at low cost.

Further , according to the present invention , since the sliding layer is made of polyethylene having an average molecular weight of about 1,000,000 or more, the excellent surface lubricating effect improves the flowability of the ground improvement material at the time of pulling out the casing. The sliding layer covers and protects the inner peripheral surface of the casing, and can significantly improve the durability of the casing, and the sliding layer itself has excellent abrasion resistance, impact resistance and chemical resistance. Without being easily worn or corroded,
Good surface lubricity can be maintained and can be used for a long time.

According to the second aspect, when a sliding layer is formed by attaching a plate made of a polymer material along the inner peripheral surface of the casing, the sliding layer is integrally fixed to the casing by the anchor portion. Therefore, the sliding layer does not separate from the casing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a soil improvement pile forming apparatus showing an embodiment of the present invention.

FIG. 2 is an enlarged detailed vertical sectional view of a casing having a sliding layer formed on an inner peripheral surface.

FIG. 3 is an explanatory view of an apparatus for testing the sliding properties of various materials used for a sliding layer.

FIG. 4 is a graph showing the results of a test performed by the slip test apparatus of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Hopper 4 Sliding layer 5 Through-hole 6 Anchor part S Ground improvement material P Ground improvement pile

Claims (2)

(57) [Claims] A ground improvement material is charged into a casing penetrating into the ground, and the ground improvement material inside the casing is discharged into the ground while the casing is being pulled out to form a ground improvement pile. in soil improvement pile reclamation device, in a casing circumference, average molecular weight to have a desired thickness of about 100
An improved soil improvement pile forming device comprising a sliding layer made of more than 10,000 plate members made of polyethylene . 2. A plurality of through holes are provided in the casing at appropriate intervals.
Provided in each through hole, the same material as the polymer material plate material
2. An anchor portion formed integrally with this plate material.
The soil improvement pile preparation device according to any one of the above.