JPH0978568A - Ground improvement equipment - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a ground improvement device capable of freely adjusting the amount of excavated soil while maintaining the excavation stirring rod at an optimum rotation speed for excavation stirring. An excavation head is provided at a lower end of a rod, an agitating member having an outer diameter equal to or smaller than an outer diameter of the excavation head is provided above the rod, and an outer diameter is appropriately smaller than the outer diameter of the excavation head from the upper position to a position near an upper end of the rod. An excavation stirring rod provided with each screw blade is rotatably connected to a drive shaft of a rotary drive device supported so as to be vertically movable and hung down, and a casing having an outer diameter appropriately smaller than the outer diameter of the excavation head is The ground, which is rotatably fitted to the screw blade portion for transportation of the excavation stirring rod and the screw blade, has a shutter openably and closably attached to the earth and sand inlet at the lower end of the casing, and is equipped with a drive means for opening and closing the shutter. Improved device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement apparatus for improving a ground by excavating a vertical hole in an original ground by rotating an excavation stirring rod and mixing a ground improvement material such as cement milk with the excavated earth and sand.

[0002]

2. Description of the Related Art Generally, when a soft ground is hardened by injecting and mixing a ground hardening material such as cement milk into excavated earth and sand, depending on the properties of the original ground, a large amount of several tens of% by volume ratio to the ground soil. The injection of cement milk increases the volume of the treated ground, which may cause the ground to rise or the ground to spread laterally and adversely affect existing surrounding structures.

[0003] Therefore, conventionally, a rotary drive device in which a plurality of excavation stirring rods each having a screw blade for conveyance on the outer circumference of the rod, a drilling head on the lower end of the rod, and stirring blades on the upper side thereof is supported so as to be vertically movable. Using a ground improvement device that is drooped and connected in parallel, while excavating a plurality of vertical holes in the soft ground by rotating the multiple excavation stirring rods, injecting with screw blades for transportation from within each vertical hole The amount of excavated earth and sand corresponding to the amount of cement milk to be discharged is discharged, and then the cement milk is injected into each vertical hole and mixed with the residual excavated earth and sand.

[0004]

However, in the above-mentioned conventional ground improvement device, since the discharge amount of excavated earth and sand is adjusted by changing the rotation speed of the screw blade for conveyance, the excavated earth and sand is excavated. The effective rotation speed of the drilling head and stirring blade cannot be obtained when adjusting the discharge amount of
There was a drawback that drilling and stirring were insufficient.

The first invention of the present application aims at adjusting the amount of soil removal while maintaining the rotation speed of the excavation stirring rod at the optimum speed for excavation stirring. An excavation stirring rod having an outer diameter equal to or smaller than the outer diameter of the excavation head, and a screw blade for conveyance, which is appropriately smaller than the outer diameter of the excavation head, is provided between the upper portion and the vicinity of the upper end of the rod. A casing having an outer diameter appropriately smaller than the outer diameter of the excavating head is connected to a drive shaft of a rotary drive device supported by the shaft, and a casing having an outer diameter that is appropriately smaller than the outer diameter of the excavating head is attached to the screw blade portion of the excavating stirring rod. Ground improvement, which is rotatably fitted, has a shutter openably and closably attached to the earth and sand intake at the lower end of the casing, and is equipped with drive means for opening and closing the shutter. To provide a location.

In addition to the problems of the first invention, the second invention of the present application has an object of orderly discharging earth and sand conveyed in the casing to the ground. As a means for solving the problem, the casing of the first invention is used. A plurality of earth-discharging windows are opened on the peripheral wall at an interval above and below each other, and lids are attached to the respective earth-discharging windows so as to be openable and closable, and a driving means for independently opening and closing each lid is provided. Provide a ground improvement device.

The "stirring member" in the first invention of the present application includes a propeller blade, a one-turn spiral blade, and various other stirring members. Further, the above-mentioned "casing" is appropriately selected as one that is rotated in the direction opposite to the direction of the excavation stirring rod, or one that is not rotated. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to FIG. 1, a mast (2) is vertically connected to a front end of a base machine (1) by a guide rail (3) laid along the entire length of the mast (2). ), (3) support the holder (4) slidably up and down, and suspend it vertically by a wire (6) hanging from the top sheave (5).
, Two rotary drive devices (7) and (7) each having a motor and a speed reducer are mounted in parallel, and the rotary drive devices (7) and (7) output the speed reducer as shown in FIG. An agitating rod drive shaft (8) whose rotation is transmitted from the shaft through a gear train, and a casing drive ring which surrounds the drive shaft (8) and whose rotation is transmitted from the drive shaft (8) through the gear train. (9) is projected, the upper end of the excavation stirring rod (10) is connected to one drive shaft (8), and the other driving ring (9) is rotatably fitted to the stirring rod (10). The upper end of the cylindrical casing (11) is connected via a cylindrical cylinder housing (12) surrounding the rod (10) and a swivel joint (13).

The excavation stirring rod (10) has a hollow rod (14) at the lower end of which an excavation head (15) is provided, and above the excavation stirring rod (15), the same outer diameter as the outer diameter and a smaller outer diameter. The propeller-type stirring blades (16) are provided with screw blades (17) for transportation, which have an outer diameter appropriately smaller than the outer diameter of the excavating head (15), from the upper portion to near the upper end of the rod. A cement milk supply pipe (18) as a ground improvement material is vertically passed through the rod (14), and its injection port is provided at the lower end of the excavation head (15).

The casing (11) is composed of double walls, and an annular gap (19) extending over the entire length is formed between the both walls, and the outer diameter thereof is appropriately made smaller than the outer diameter of the excavating head (15). Then, the casing (11) is rotatably fitted to the screw blade (17) portion of the stirring rod (10), and an annular earth and sand intake (20) between the hollow rod (14) at the lower end of the casing (11). To the shutter (2
1) is attached so that it can be opened and closed freely.

The shutter (21) is a ring-shaped member capable of closing the earth and sand intake port (20), and is slidable in the axial direction on the hollow rod (14) to open and close the intake port (20). While being fitted, the casing (1
Two shutter opening / closing rods (22) and (22) slidably inserted in the annular gap (19) of 1) are connected to the respective lower ends.

As a means for opening and closing the shutter (21), a single-acting hydraulic cylinder (2) for driving the shutter is provided on the inner wall surface of the cylinder housing (12) as shown in FIG.
3) and (23) are mounted vertically, and the rams (24) and (24) of both cylinders are attached to the shutter opening / closing rod (2).
2), connected to the upper end of (22), the cylinder (23),
By driving (23), the rods (22) and (22) are moved up and down to move the shutter (21) up and down to open and close the intake port (20).

In this example, the casing (11) is further added.
As an example, the first, second, third and fourth earth discharging windows (25a), (25b), (25
9) C) and (25d) are sequentially placed at positions vertically spaced apart.
It is opened by displacing it by 0 degrees, and the curved plate-shaped lids (26) are slidably inserted into the annular gaps (19) of the double walls at the positions corresponding to the respective soil discharge windows, and Four lid opening / closing rods (27) slidably inserted into the annular gap (19) are connected to respective lower ends of the lid opening / closing rods (26) to drive the four lids as opening / closing driving means. , Single-acting hydraulic cylinders (28) are mounted vertically on the inner wall surface of the cylinder housing (12), and their rams (28 ') are connected to the upper ends of the lid opening / closing rods (27). . Each lid opening / closing rod (27) ...
Are arranged in parallel with each other in the longitudinal direction of the casing (11) at equal intervals as shown in FIG.

The shutter driving hydraulic cylinder (2
3), (23) and the lid driving hydraulic cylinder (28) ...
In the swivel joint (13) consisting of the fixed ring outer cylinder (29) and the rotary ring inner cylinder (30) for connecting each to the external hydraulic circuit, as shown in FIG. The hydraulic supply pipe (31) ...
Five outer hydraulic supply passages (32) respectively connected to
Are connected to the supply passages (32), respectively, and are connected to the five annular passages (33) provided on the inner peripheral surface of the outer cylinder (29) and the annular passages (33). A swivel circuit is constituted by five inner hydraulic pressure supply passages (34) ... Which vertically pass through the cylinder (30) and open the cylinder housing (12), and the shutter drive cylinders (23), (23). Is connected to one inner hydraulic supply pipe (34) by a pipe (35) as shown in FIG. 2, and the lid drive cylinders (28) ... Inside hydraulic supply pipe (34) ... and pipe (36) ...
Are connected to each other.

An annular cap (37), which is rotatably fitted to the hollow rod (14), is attached to the upper end opening of the casing (11) to prevent the entry of earth and sand into the cylinder housing (12). (Fig. 2,
3). (38) is a steady rest band of both casings (11) and (11) (FIG. 1).

The operation of the above example will be described below together with a usage example. As an example, as shown in FIG. 5, a soft layer (A), an improved unsuitable stratum (B) including an unsuitable stratum (B) below which is unsuitable for mixing and stirring with a ground hardening material such as industrial waste, and the like. The case where it is used for the hardening treatment of the ground having the layer (C) will be described. First, a soil discharge amount corresponding to the amount of cement milk to be injected is set in advance, and a required rotation continuation time at the optimum excavation stirring rotation speed of the excavation stirring rod (10) required to achieve the set soil discharge amount is set. Calculate it. Hydraulic cylinders (23), (23) for shutter drive by operating the hydraulic circuit
5 is extended to push down the shutter (21) via the shutter opening / closing rods (22) and (22) to open the earth and sand intake port (20).
Further, in this example, the hydraulic cylinder (28) for driving the lid of the first earth unloading window (25a) is driven to extend, and the lid (26) is pushed down via the lid opening / closing rod (27). (25a) is opened and the other 2nd, 3rd and 4th earth removal windows (2
5b), (25c), and (25d) are placed in a closed state, and in this state, the rotation drive device (7) is started to rotate the excavation stirring rod (10) at the optimum excavation stirring rotation speed and the casing (11). Is rotated in the opposite direction to start excavation in the soft layer (A). Drilling head (1
The earth and sand excavated by 5) is agitated by the agitation blade (16), and a part of the earth and sand enters the casing (11) through the earth and sand intake (20) and is conveyed upward by the screw blade (17), and the lowest It is discharged from the first earth discharging window (25a) to the outside, and at that time, since the first earth discharging window (25a) is located near the ground, the earth discharging is deposited on the ground in an orderly manner. The earth and sand remaining in the borehole is the casing (11).
It is retained in the annular space between the outer peripheral surface of the and the inner wall surface of the borehole.

When the excavation is carried out to the front of the unsuitable stratum (B) as shown in FIG. 2B, the shutter (21) is continuously opened, and the first earth unloading window (25a) is closed and newly opened. The second earth discharging window (25b) is opened, and the other third and fourth earth discharging windows (25c) and (25d) are continuously closed. In that state, excavation is similarly performed on the unsuitable formation (B). In the excavation in this stratum (B), since the preceding excavated earth and sand is filled in the space between the outer peripheral surface of the casing (11) and the inner wall of the excavation hole, the excavation speed is slowed to slow down the stratum (B). Most of the improved unsuitable earth and sand excavated in (1) is taken into the casing (11) through the earth and sand inlet (20) and is discharged through the second earth discharge window (25b), and is hardly left in the excavation hole.

After digging up to the front of the support layer (C) as shown in FIG. 3C, the shutter 21 is kept open, the second earth discharging window 25b is closed, and the third earth discharging window 25c is newly added. ) Is opened, and excavation to the support layer (C) is continued. The shutter (21) is closed when the rotation duration of the excavation and stirring rod (10) until the set amount of discharged soil is reached, thereby stopping the earth and sand intake from the earth and sand intake port (20). 3 The earth removal from the earth removal window (25c) is almost stopped, and the set amount of earth is completed.

During the earth unloading work up to the above set amount, all the other earth unloading windows located in the ground are closed and the earth and sand are not taken in or the earth is not evacuated from the windows, so that the excavation and stirring rod (1
When the required rotation duration of 0) has elapsed, the set earth removal amount is achieved almost as calculated.

When the support layer (C) is dug to the required depth as shown in FIG. 2 (D), the excavation stirring rod (10) and the casing (11) are stopped, and all the earth discharging windows (25a) to (25).
d) is closed, and then the excavating and stirring rod (10) and the casing (11) are respectively rotated in the opposite directions as shown in (e) in the figure, and cement milk is injected from the injection port at the lower end of the excavating head (15). Then, the cement milk and the residual earth and sand are mixed and stirred, and the mixture is withdrawn to the ground.
At this time, since the amount of earth and sand corresponding to the amount of cement milk to be injected has been discharged from the excavation hole in advance, the ground does not rise or expand laterally after the hardening treatment.

[0021]

According to the ground improvement device of the first invention of the present application,
While excavating and stirring rod is rotated at the optimum rotation speed for excavation and stirring, soil can be optionally discharged by opening and closing the shutter, which allows excavation and stirring to be performed sufficiently and a desired amount of soil removal to be adjusted. To be able to achieve
Further, in the case of using in the ground including the unsuitable formation, it is possible to discharge the improved unsuitable soil in the formation without leaving it in the excavation hole by slowing down the excavation speed when reaching the improved unsuitable formation. , Its utility value is high.

According to the ground improvement apparatus of the second invention of the present application, the earth discharging window at the height closest to the ground surface among the plurality of earth discharging windows is opened along with the excavation. Can be sent to the ground in an orderly manner, and the work space around the site can be kept clean.If the method of checking the amount of earth removal by the duration of excavation and earth removal work is adopted, The above method can be performed without any problem by closing the soil discharge window located inside.

[Brief description of drawings]

FIG. 1 (a) is a partially omitted side view of the ground improvement device of the present invention. (B) It is a front view same as the above.

FIG. 2 is a partially omitted enlarged vertical front view of a casing portion.

FIG. 3 is a partially omitted enlarged vertical side view of the same.

FIG. 4 is an enlarged cross-sectional view of a casing portion.

FIG. 5 (a) is a schematic diagram of the excavation preparation stage. (B) It is a schematic diagram of a soft layer excavation stage. (C) It is a schematic diagram at the stage of excavation of an unsuitable formation.

FIG. 6 is a schematic diagram of (d) support layer excavation stage. (E) It is a schematic diagram of the cement milk injection and withdrawal stage.

[Explanation of symbols]

 7 Rotational drive device 8 Drive shaft 10 Excavation stirring rod 11 Casing 14 Hollow rod 15 Excavation head 16 Stirring blade 20 Sediment intake 21 Shutter 23 Hydraulic cylinder for shutter drive 25a, 25b, 25c, 25d Exhaust window 26 Lid 28 Lid drive Hydraulic cylinder

Claims (2)

[Claims] 1. An excavation head is provided at a lower end of a rod, a stirring member having an outer diameter equal to or smaller than an outer diameter of the excavation head is provided above the rod, and an outer diameter of the excavation head is appropriately smaller than an outer diameter of the excavation head from the upper position to a vicinity of an upper end of the rod. An excavation stirring rod provided with each screw blade for transportation is hung so as to be rotatably connected to a drive shaft of a rotation drive device that is supported so as to be able to move up and down, and a casing having an outer diameter appropriately smaller than the outer diameter of the excavation head. The excavation stirring rod is rotatably fitted with a screw blade portion for transportation of the screw blade, and a shutter is openably and closably attached to the earth and sand intake port at the lower end of the casing, and a driving means for opening and closing the shutter is provided. Ground improvement device. 2. A plurality of earth-discharging windows are opened on the peripheral wall of the casing with a vertical interval therebetween, and lids are attached to the earth-discharging windows so as to be openable and closable, and the lids are independently opened and closed. The ground improvement device according to claim 1, wherein the ground improvement device is equipped with: