JP2879314B2 - Vibration-free and noise-free compacted sand pile construction 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 forming a compacted sand pile of a vibration-free and noise-free type (the sand pile includes a clavel pile).

[0002]

2. Description of the Related Art A conventional vibration-free and noise-free compacted sand pile construction method uses a casing having spiral blades on the outer peripheral surface, and corrects the casing when penetrating the casing (at the time of initial penetration and at the time of re-penetration). When the casing is pulled out, the casing is rotated in reverse (for example, Japanese Patent Publication No. Sho 62-2).
No. 7204).

[0003] The basic principle of compacted sand pile formation is that the sand in the casing is discharged to the trace when the casing is pulled out, and a relatively loose sand column formed by the sand of the discharged scale is re-penetrated into the casing. Sometimes it is compressed under the constraint of the surrounding ground, and the surrounding ground is compacted together with the sand column.However, in the conventional method using a casing with spiral blades, when the casing penetrates, A part of the ground soil is discharged to the ground, the ground soil in the area where the spiral blade passes is disturbed, and a thick layer of disturbed soil is formed between the sand pillar and the ground soil when the casing is pulled out. Because it is formed, even if the casing is re-penetrated,
There is a problem that the layer of the disturbed soil acts as a buffer to hinder the effect of compacting the sand column and the original ground. This problem is disclosed in Japanese Patent Application Laid-Open No. 6-200520. Even if a casing elevating device that can expect a large penetration force (compaction force) as described above is not solved.

[0004]

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a new non-vibration and noise-free compacted sand pile in which a large penetration force effectively acts to improve the compaction effect of a sand column and an original ground. It is to provide a construction method.

[0005]

The construction of the vibration-free and noise-free compacted sand pile construction method of the present invention (hereinafter, simply referred to as the method of the present invention) is characterized in that the casing is placed at a predetermined depth in the ground along a supporting leader. After penetrating to the surface, the process of drawing out the casing appropriately and the process of re-penetrating the casing are repeated until reaching the ground surface, when forming a compacted sand pile on soft ground, no spiral blade is attached to the outer peripheral surface Using a casing,
While rotating the casing to cut friction with the ground,
The point is that the casing is moved in and out by a casing lifting / lowering device which can obtain a reaction force from the leader at the time of penetration and withdrawal.

The casing used in the method of the present invention is preferably provided with a drilling bit for assisting intrusion at its tip. The drilling bit functions when the casing is rotated in one direction (normal rotation). And the one having no direction to exert the excavation function when the casing rotates in any direction may be used.

In the method of the present invention, the casing can be turned in any direction at the time of penetration and withdrawal, except when a casing having a directional drill bit attached to the lower end is used. It may be.

The casing elevating device used in the method of the present invention is arbitrary as long as a reaction force from the leader can be obtained at the time of penetration and withdrawal. For example, a device using a rack and a pinion, a device using a chain and a sprocket, a device using a wire rope And the like.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Is a leader erected on the front surface of the construction machine body 1, and 3 is a casing. The casing 3 differs from the casing in the conventional method in that no spiral blade is attached to the outer peripheral surface.

The upper end of the casing 3 is rotatably connected to a non-rotating portion 5 via a casing turning device 4 of a swivel mechanism, and the non-rotating portion 5 has a sand hopper 6 and a casing. A casing-side mechanism 8 of the elevating device 7 is provided.

The casing lifting / lowering device 7 receives a reaction force from the leader 2 when the casing 3 penetrates into the ground and when the casing 3 is pulled out. When the casing 3 is of a rack and pinion type, it is driven by the casing side mechanism 8. A pinion for the device is provided, and a rack that engages with the pinion is provided on the reader 2.

Reference numeral 9 denotes a rod-shaped excavation bit attached to the tip of the casing 3. When the drill bit 9 penetrates into the ground while rotating the casing 3, the excavation bit 9 contacts the ground that the tip of the casing 3 hits. Excavation in a ring shape helps the penetration of the casing 3.

[0013] The compaction sand pile forming operation includes a step of appropriately extending the casing 3 after the casing 3 has penetrated to a predetermined depth in the ground, and a step of re-penetrating the casing 3.
It is repeated in order until the surface reaches the ground surface, during which the sand in the casing 3 is discharged in a drawing step and a compressive force is applied to the sand in a re-penetration step.
At the time of penetration (at the time of initial penetration and re-penetration) and at the time of withdrawal, the casing 3 is rotated in order to cut the friction between the outer peripheral surface of the casing 3 and the ground to facilitate the penetration and withdrawal of the casing 3.

When the drill bit is not attached to the tip of the casing 3 or when the drill bit has no direction (the drill bit 9 shown in the figure is rod-shaped and has no direction), the casing 3 is inserted and pulled out. The direction of rotation of the casing 3 is arbitrary and may be a reciprocating rotation. However, when a directional drill bit is mounted, at least the rotation at the time of initial penetration of the casing 3 is performed in the normal direction (the drill bit exerts a drilling function). Direction).

[0015]

The method of the present invention is as described above, and the use of a casing having no spiral blades on the outer peripheral surface does not cause the discharge and disturbance of the original ground soil around the casing. A large penetration force when re-penetrating the casing with the casing elevating device that can obtain the reaction force from the leader when penetrating and pulling out effectively acts, tightening not only the sand column (sand pile part) but also the surrounding ground The hardening effect is improved, and the above-mentioned problems of the conventional method are surely solved.

[Brief description of the drawings]

FIG. 1 is a side view of an example of an apparatus for carrying out the method of the present invention.

[Explanation of symbols]

1: Construction machine body, 2: Leader, 3: Casing, 4:
Casing rotating device, 5: non-rotating portion, 6: hopper,
7: Casing elevating device, 8: Casing side mechanism,
9: drill bit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-200520 (JP, A) JP-A-60-65814 (JP, A) JP-A-3-18233 (JP, U) 27204 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) E02D 3/10 104

Claims (3)

(57) [Claims] 1. After the casing is penetrated to a predetermined depth in the ground along a supporting leader, a step of drawing out the casing appropriately and a step of re-penetrating the casing are sequentially repeated until reaching the surface of the ground, so that the soft ground When creating a sand compaction, use a casing without spiral blades on the outer peripheral surface, and rotate the casing to cut friction with the ground, while reacting from the leader at the time of penetration and pulling out A vibration-free and noise-free compacted sand pile construction method characterized in that the casing is penetrated and pulled out by a casing elevating device capable of obtaining the above. 2. The method of claim 1, wherein the casing is provided with a drill bit for assisting penetration. 3. The method according to claim 1, wherein the rotation of the casing is a reciprocating rotation.