JP2668664B2 - Ground improvement method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the installation of a large number of pillars made of a vertically permeable drainage material such as sand or lime on the ground to shorten the drainage distance to promote consolidation, and also to improve the shear strength of the ground. The present invention relates to a soil improvement method and a device for strengthening a ground.

[0002]

2. Description of the Related Art A sand drain method is known as this type of method. Referring to FIG. 8, an auger type is provided. An auger 1 is installed at a predetermined position, and a hole is drilled by the auger 1 to a predetermined depth. Then, sand is charged into a hopper 2 provided immediately above the auger 1 and compressed air is sent.

The auger 1 is gently pulled out without rotating while sand is pressed through the hollow shaft of the auger 1 to complete the construction of the drain pile.

[0004] This auger-type sand drain method is
Compared to the mandrel type, which is another method in which the casing is driven to a predetermined depth by vibration, sand is put into the casing through a popper, and the casing is pulled out while discharging from the tip of the casing, the noise is small and it is applied to adjacent structures. Little effect.

[0005]

However, the same applies to the mandrel method, but in this auger type sand drain method, sand is discharged by sending compressed air, and the auger is used to form a drain pile having a large diameter. If the diameter of the auger 1 is also increased, the sufficient effect cannot be obtained, and the sand inside the auger 1 may become a bridge and may not be discharged properly.

Further, when the tip of the auger 1 is opened and closed so as to open the beak and the sand is discharged from the opening, the excavation mechanism is lacking in this portion,
Excavation performance also decreases.

Further, it is necessary to treat the soil removed by the auger 1, which is also troublesome.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the disadvantages of the prior art, and to reduce the risk of bridging of drainage filler such as sand or lime introduced into a rotary drilling casing without causing bridging even when the rotary drilling casing has a large diameter. It can be reliably discharged from the lower end of the excavating casing, does not reduce the excavating performance of the lower end of the rotary excavating casing, and does not discharge all of the earth and sand excavated by the rotary excavating casing to the ground, but a part or It is an object of the present invention to provide a soil improvement method and apparatus which can not only save the time and effort for discharging earth and sand because most of the material is compacted on the hole wall, but also prevent collapse of the hole wall.

[0009]

According to the present invention, as a ground improvement method, a drainage filler such as sand or lime can be introduced into the inside from the upper end, and a drilling head is provided at the lower end. And a rotary rod that is inserted into the rotary drilling casing and has a drainage filler anti-caking plate in the middle thereof.The lower end of the rotary drilling casing has a lower opening of the rotary drilling casing. A closing snub is provided, and a drill bit is provided at a portion below the snub to protrude from the lower end of the rotary excavating casing, and the snub is opened and closed by vertically moving the rotary rod at the upper end of the rotating rod. An open / close cylinder is incorporated, and the rotary excavating casing and the body or the rotating rod use a ground improvement device provided with an engagement means that allows vertical relative position fluctuation. The bottom excavation is closed, and the ground is excavated by rotating the rotary excavating casing and the rotating rod together in a state where they are mutually locked by the engaging means. The filler is charged, the rotating rod is moved up and down by the opening and closing cylinder, and the drainage filler is stirred into the drilling hole by the anti-consolidation plate to open and close the body, and the draining filler is charged into the drilling hole. The gist is to pull out the rotating rod.

As a ground improvement device, first, a driving device and a fixed hopper having an inlet for a drainage filler such as sand or lime are provided so as to be vertically movable along a guide pipe of a leader. A rotary hopper that engages with the fixed hopper is provided at the upper end of the rotary drilling casing that is driven by, and a drilling head is provided at the lower end, and a rotary rod provided with a drainage filler anti-caking plate in the form of a vertical plate in the middle. The rotary drilling casing is inserted into the rotary drilling casing, and a lower end of the rotary rod is provided with a snub at an opening of a lower end of the rotary drilling casing. An opening / closing cylinder for opening and closing the rotating body by moving the rotating rod up and down is incorporated, and the rotating excavating casing and the rotating body or the rotating rod are vertically positioned relative to each other. Secondly, the opening / closing cylinder is a center hole type cylinder, and the rotating rod is also a hollow rod communicating with the opening / closing cylinder, and a swivel device is combined with the opening / closing cylinder. Water and air can be poured out, 3rd
In addition, the rotary excavating casing is provided with a screw blade on the outer periphery thereof, and is provided with a trowel portion having a curved pressing surface as a side surface which projects outward from the peripheral surface of the rotary excavating casing to the screw blade outer edge position.

[0011]

According to the first and second aspects of the present invention, the rotating rod is moved up and down by the opening / closing cylinder, and the rotating casing is opened and closed while the drainage filler is charged into the drilling hole. Although the rod is pulled out, at this time, the anti-caking plate provided in the middle of the rotating rod agitates the drainage filling material, so that the drainage filling material does not cause a bridge even from the lower end of the rotation drilling casing even when the diameter of this rotary drilling casing is large. Can be discharged reliably.

Further, since the excavation bit is provided not only on the excavation head at the lower end of the rotary excavating casing but also on the lower side of the sled, which protrudes from the lower end of the rotary casing, the slidable body closes the lower end opening of the rotary casing. When excavating the ground by co-rotating the rotating casing and the rotating rod in a state where they are mutually locked by the engaging means, there is no unexcavable portion at either the lower end of the rotating excavating casing or the lower side of the sled. , Efficient work can be secured.

According to the third aspect of the present invention, in addition to the above operation, excavation can be made easier by allowing water or air to be discharged from the lower end of the rotating rod.

According to the fourth aspect of the present invention, the rotary excavating casing is provided with a screw blade on the outer periphery, and a soldering portion having a curved pressing surface protruding outward from the peripheral surface of the rotary excavating casing to the outer edge position of the screw blade. Since the earth and sand cut by the rotary excavating casing are transferred upward by the lifting action due to the rotation of the screw blades, at the time of this transfer, they are pushed outward by the iron part and are compacted in the hole wall. You.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a vertical sectional side view showing an embodiment of the ground improvement apparatus of the present invention, FIG. 2 is a cross-sectional plan view of the essential parts of the same, and FIG. 3 is a vertical sectional side view of the essential parts of the same.

The ground improvement apparatus of the present invention comprises a drive unit 4 provided to be vertically movable along a guide pipe 3 of a leader (mast) of a heavy construction machine, and a rotary excavating casing 5 connected to the drive unit 4 and driven to rotate. But rotary drilling casing 5
A rotary hopper 6 is provided at the upper end of the hopper. The upper portion of the rotary hopper 6 is engaged with the lower portion of a fixed hopper 7 having an inlet 7a for drainage filler such as sand or lime.

The fixed hopper 7 is provided so as to be vertically movable along the guide pipe 3 of the leader, like the drive unit 4.

At the lower end of the rotary drilling casing 5, a drilling head 9 having a drilling bit 8 implanted therein is provided so as to project to the outer periphery.

A rotary rod 11 is provided so as to pass through the rotary excavating casing 5. A solidification preventing plate 12 of drainage filler is provided in a vertical plate on an intermediate side thereof, and the rotary excavating casing 5 is provided at a lower end thereof. In order to open and close the lower end opening 10, there is provided a conical drum-shaped snooping body 13 whose diameter increases downward.

Further, a portion projecting below the lower end of the rotary excavating casing 5 with the lower end opening 10 of the rotary excavating casing 5 closed under the snake body 13 is formed into a conical drum shape which is tapered downward. The whole is made into a top shape together with the snake body 13, and a drill bit 8 is provided in this portion.

On the other hand, an opening / closing cylinder 14 for opening and closing the snub body 13 by moving the rotating rod 11 up and down is incorporated at the upper end of the rotating rod 11, and a hydraulic swivel device 15 is installed around the cylinder. The hydraulic control of the lever opening / closing cylinder 14 can be performed.

The opening / closing cylinder 14 is a center-hole type cylinder, and the rotating rod 11 is also a hollow rod communicating therewith. Further, a swivel device 16 is combined at the upper end of the opening / closing cylinder 14, and the opening / closing cylinder 14 and the rotating rod 11 Water and air can be discharged from the lower end of the conical drum below the body 13 through the inside.

The key groove 17 is formed by vertically projecting two projecting pieces from the inner peripheral wall near the lower end of the rotary excavating casing 5.
And a flange-shaped key 19 whose end is inserted into the key groove 17 is provided so as to protrude to the side and upward of the conical drum-shaped snooping body 13 having the downwardly enlarged diameter. In combination with key 19, rotary drilling casing 5
It is assumed that the body 13 is a mutual engagement means that allows a change in the vertical relative position.

The rotary excavating casing 5 is provided with screw blades 18 on the outer periphery thereof, and as shown in FIG. 4 and below, a curved pressing surface projecting outward from the peripheral surface of the rotary excavating casing 5 to the outer edge position of the screw blades 18 is a side surface. An ironing section 20 is provided. Continuity with the screw blades 18 can be ensured if the trowel unit 20 is swung and raised like a thick screw.

Next, a ground improvement method using the ground improvement apparatus of the present invention will be described with reference to FIGS.

As shown in FIG. 4, when the open / close cylinder 14 is contracted and the lower end opening 10 of the rotary excavating casing 5 is closed by the pinch body 13 and the rotary excavating casing 5 is driven to rotate by the drive unit 4, a keyway is obtained. With the combination of 17 and key 19
The excavation bit 8 of the excavation head 9 at the lower end of the rotary excavation casing 5 and the excavation bit 8 below the snake body 13 are excavated.

At this time, water or air is poured out from the lower end of the conical drum below the snout body 13 through the opening / closing cylinder 14 and the rotating rod 11 via the swivel device 16 to facilitate excavation. The earth and sand cut by the excavating bit 8 are transferred upward by the lifting action due to the turning of the screw blades 18. At the time of this transfer, the curved pressing surface of the trowel portion 20 pushes the earth and sand outward to consolidate it into the hole wall. . In this way, not all of the excavated earth and sand is discharged, but part or most of the excavated soil is condensed into the hole wall, so that not only can the time and effort for soil discharge be eliminated, but also the collapse of the hole wall can be prevented, and ,
Friction resistance during excavation is also reduced.

After excavation to a predetermined depth as shown in FIG. 5, sand 21 as a drainage filler is put into the rotary excavating casing 5 from the input port 7a, and the rotary rod 11 is moved up and down by the opening / closing cylinder 14. While the filled sand 21 is being stirred by the anti-consolidation plate 12, the snake body 13 is opened and closed, and as shown in FIG. The drilling casing 5 and the rotating rod 11 are pulled out.

When the sand 21 is discharged, since the knurled body 13 is shaped like a conical drum whose diameter increases downward, the sand 21 can be guided to spread outward and spread efficiently. Further, the rotary excavation casing 5 and the rotary rod 11 at the time of pulling out are pulled out while rotating in the opposite directions.

As shown in FIG. 7, the construction of the columnar body in which the drainage filling material with sand 21 is filled in the excavation hole is completed.

Although the above embodiment has been described with reference to the case where the sand 21 is used as the drainage filler such as sand and lime, it is also possible to use chemic lime (limestone) as the drainage filler, which has a greater water absorbing effect.

The rotary excavating casing 5 and the rotary rod
11 can be engaged with each other so as to allow a change in the relative position in the vertical direction at locations other than the snake body 13, and the engagement means may be engagement other than the key and the key groove.

[0033]

As described above, the soil improvement method and apparatus according to the present invention are capable of causing a drainage filler such as sand or lime to be charged into a rotary excavation casing to cause a bridge even when the diameter of the rotary excavation casing is large. And it can be reliably discharged from the lower end of the rotary excavation casing.

Further, since the drainage filler is discharged from the lower end of the rotary excavating casing, excavation can be performed below this portion, so that the excavating performance is not reduced.

Further, not all of the earth and sand excavated by the rotary excavation casing is discharged to the ground, but part or most of the earth and sand is compacted on the hole wall, so that not only the work of discharging the earth and sand can be saved but also the collapse of the hole wall. Can also be prevented

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of a ground improvement device of the present invention.

FIG. 2 is a cross-sectional plan view of a main part showing one embodiment of the ground improvement device of the present invention.

FIG. 3 is a longitudinal sectional side view of a main part showing one embodiment of the ground improvement device of the present invention.

FIG. 4 is a side view of a first step showing one embodiment of the ground improvement method of the present invention.

FIG. 5 is a side view of a second step showing one embodiment of the ground improvement method of the present invention.

FIG. 6 is a side view of a third step showing one embodiment of the ground improvement method of the present invention.

FIG. 7 is a side view showing a completed construction state of the ground improvement method of the present invention.

FIG. 8 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

1 ... Auger 2 ... Hopper 3 ... Guide pipe 4 ... Drive device 5 ... Rotating drilling casing 6 ... Rotating hopper 7 ... Fixed hopper 7a ... Input port 8 ... Drilling bit 9 ... Drilling head 10 ... Opening 11 ... Rotating rod 12 ... Solidification prevention Plate 13 ... Plug 14 ... Opening / closing cylinder 15 ... Hydraulic swivel device 16 ... Swivel device 17 ... Key groove 18 ... Screen blade 19 ... Key 20 ... Iron part 21 ... Sand

Claims (4)

(57) [Claims] 1. A rotary drilling casing having a drilling head at the lower end, into which a drainage filler such as sand or lime can be charged from the upper end, and the rotary drilling casing is inserted into the rotary drilling casing, and the intermediate part is provided with It consists of a combination with a rotating rod provided with an anti-consolidation plate for drainage filler, and at the lower end of the rotating rod is provided a stopper for closing the lower end opening of the rotary excavating casing, and protrudes from the lower end of the rotary excavating casing below the stopper. A drilling bit is provided in a portion to be rotated, and an opening / closing cylinder for opening and closing the snub body is installed at the upper end of the swivel rod by vertically moving the swivel rod. Using a ground improvement device provided with an engagement means allowing a position change, a rotary excavation casing is closed in a state in which a lower end opening of a rotary excavation casing is closed with a sniper and mutually locked by the engagement means. After excavating the ground by rotating the rotating rod and the rotating rod together and excavating to a predetermined depth, put the drainage filling material in the rotating excavating casing, move the rotating rod up and down with the opening and closing cylinder, and use the solidification prevention plate. A ground improvement method characterized by pulling out a rotating drilling casing and a rotating rod while opening and closing a body while stirring a drainage filler and putting the drainage filler into a drilling hole. 2. A driving device and a fixed hopper having an inlet for a drainage filler such as sand or lime are provided so as to be vertically movable along a guide pipe of a leader, and are provided at an upper end portion of a rotary excavating casing driven by the driving device. A rotary hopper that engages with the fixed hopper is provided, a digging head is provided at a lower end, and a rotary rod provided with a vertical plate-like anti-consolidation preventing plate for drainage filler is inserted into the rotary digging casing in the middle of the rotary hopper. At the lower end of the rod, there is provided a sled of the lower end opening of the rotary excavating casing, and at the part below the slender that projects from the lower end of the rotary excavating casing, an excavating bit is provided, and by moving the rotating rod up and down at the upper end of the rotating rod. An opening / closing cylinder for opening and closing the body is incorporated, and the rotary excavating casing and the body or the rotating rod are provided with engaging means for allowing a vertical relative position change. Characteristic ground improvement device. 3. The opening / closing cylinder is a center hole type cylinder, and the rotating rod is also a hollow rod communicating with the opening / closing cylinder, and a swivel device is combined with the opening / closing cylinder so that water or air can be discharged from the lower end of the rotating rod. 2. The ground improvement device according to 2. 4. The rotary excavating casing is provided with a screw blade on the outer periphery thereof, and is provided with a trowel portion having a curved pressing surface as a side surface which extends outward from the peripheral surface of the rotary excavating casing to the screw blade outer edge position. The ground improvement device as described.