JPH08158355A - Stabilization work of ground and device thereof - Google Patents

Abstract

PURPOSE: To stabilize a soft ground, by excavating a soft ground and injecting a stabilizing material in the excavated ground and mixing and agitating them. CONSTITUTION: A easing cutter 5 is fixed to the front end of an excavating pipe 2 and a casing cutter face is provided at the inner diameter face at the near position of the front end of the excavating pipe 2. And further, several stages of agitation blades 8 are provided on a hollow shaft 7 rising from the center of the easing cutter face. A hose 9 is connected to a swivel joint 11 installed on the upper end of the hollow shaft 7. A plurality of injection holes for the stabilizing material are provided on the hollow shaft 7 and a plurality of soil discharge holes 10 are provided at the upper part of the excavating pipe 2 above the ground. In this way, the ground can be excavated with a high vertical accuracy. As a result, stabilization of ground with a high quality and accuracy can be achieved while retaining the continuity of stabilized ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention excavates a soft ground, pours a ground stabilizing material or a hardening material (hereinafter referred to as "stabilizing material") into the excavated soil, and stirs and mixes the soft ground. The present invention relates to a ground improvement method for improvement treatment and a ground improvement device used for implementing the method.

[0002]

2. Description of the Related Art In recent years, a ground improvement method for improving soft soil by excavating soft ground, injecting stabilizer into the excavated soil, and agitating and mixing, and a ground improvement apparatus used for carrying out the method. It is widely practiced, for example, Japanese Examined Patent Publication (Kokoku) No. 4-57805 or Japanese Patent Laid-Open No. 3-129.
No. 009 publication.

According to the above-mentioned publication, when a rotary shaft having a stirring blade at its tip penetrates into the ground, an excavating soil in an amount corresponding to the amount of stabilizer used is eliminated by an earth-moving screw attached to the rotary shaft. There is described a ground improvement method and device for stirring and mixing the ground soil and the stabilizer while pulling out the rotary shaft while rotating the rotary shaft in a direction opposite to that at the time of penetration. Also,
In the above-mentioned publication, a digging rod having a stirring blade protruding above the tip of the drill bit, and a crushing blade rotatably connected to the digging rod and crushed on the inner peripheral surface of the stirring blade in a staggered arrangement with the stirring blade. Cylindrical casing pipe with blades protruding from each other is rotated in reverse, and the ground is excavated while crushing the excavated soil with the stirring blade and the crushing blade, and after reaching the predetermined depth, the stabilizer is applied from the tip of the drilling rod. While discharging, rotate the excavation rod and casing pipe in the opposite direction to that at the time of excavation, and further agitate the excavated soil with the agitating blade and the agitating blade. A ground improvement method and device for improvement treatment are described.

[0004]

In the ground improvement method described above, the soil is forcibly discharged in advance with the screw for soil discharge, and the stabilizer is injected into the ground soil during the subsequent extraction of the stirring and excavating cutter. As a result, it is possible to surely prevent the swelling of the ground caused by the injection of the stabilizer, that is, the adverse effect on the vertical direction during construction. However, since the stabilizer is directly injected into the ground soil, the ground displacement occurs in the horizontal direction, and it is not possible to deal with the adverse effects such as adversely affecting the existing structures in the vicinity. In addition, if there are obstacles or hard formations in the ground, the excavation and stirring cutter at the tip will inevitably escape (bend), resulting in insufficient ground improvement or unprocessed areas, resulting in continuous improvement ground. As a result, the strength is deteriorated, the strength and rigidity are reduced, and the water blocking property is lost.

It is noted that the above ground improvement method uses a casing pipe, but the purpose of using the casing pipe is not to prevent the stabilizer from flowing out in the horizontal direction, but to crush the lump of soil in the excavated soil. Emphasis is placed on providing crushing wings. In addition, there is no disclosure of any measure to deal with the increase in volume in soil due to the injection of stabilizers. this is,
It is also clear from the construction method that the device is lifted while discharging the stabilizer from the tip of the excavating rod after reaching the predetermined depth.

Therefore, the object of the present invention is to increase the soil volume accompanying the injection of the stabilizer by injecting the stabilizer into the excavated soil in the excavation pipe by excavating the soft ground with the excavation pipe and stirring and mixing. It is intended to eliminate all adverse effects in construction, and to provide a soft ground construction method and device for advancing excavation while maintaining high vertical accuracy with an excavation pipe.

[0007]

As a means for solving the above-mentioned problems of the prior art, the ground improvement method according to the invention described in claim 1 is provided with a casing cutter 5 at the tip edge portion, and a casing cutter 5 is provided near the tip portion. A casing cutter face 6 is provided on the inner diameter surface, and a hollow shaft 7 rising from the central portion of the casing cutter face 6 is provided with several stages of stirring blades 8 on an excavating pipe 2 which is rotated by a rotary drive device 1 while being in soft ground. The ground is excavated by penetrating vertically into the soil, and the excavated soft soil is excavated in the excavation pipe 2 and the stirring blade 8
And the stabilizer supplied through the hose 9 is poured into the soil and mixed, and the volume increase of the soil due to the injection of the stabilizer is allowed to rise in the excavation pipe 2 and the same excavation is performed. A plurality of earth discharging holes 10 provided above the pipe 2
It is characterized by natural earth removal from the ground.

Next, in the ground improvement device according to the second aspect of the present invention, the casing cutter 5 is provided at the tip edge portion of the excavation pipe 2 rotated by the rotary drive device 1, and the tip end portion of the excavation pipe 2 is provided. A casing cutter face 6 is fixedly provided on the inner diameter surface in the vicinity thereof, and a hollow shaft 7 rising from the central portion of the casing cutter face 6 is provided with several stages of stirring blades 8.
The swivel joint 11 provided at the upper end of the drilling pipe 2
The hose 9 inserted through the upper end opening of the drill is connected, the hollow shaft 7 is provided with a plurality of stabilizer injection holes 12, and the excavation pipe 2 is provided with a plurality of earth discharge holes 10 above the ground. And

The excavating pipe 2 according to claim 2
Is also characterized in that the outer casing 3 and the inner casing 4 are configured to be expandable and contractable with a structure capable of transmitting a rotational force.

[0010]

The casing cutter 5 at the tip of the excavation pipe 2 excavates not only general soil in soft ground, but also sharp ground for hard ground such as gravel layer, pumice, rock, etc., or obstacles such as pine piles. Therefore, it is possible to prevent the so-called escape (bend) of the excavation pipe 2 against these, and excavation with high vertical accuracy is possible.

The casing cutter face 6 excavates only the soil that has entered the excavation pipe 2. Then, the stirring blade 8 provided on the hollow shaft 7 rising from the center of the casing cutter face 6 and the injection hole 12 for injecting the stabilizer.
Since the stabilizer is injected into the soil completely isolated from the surrounding ground in the excavation pipe 2 to perform the stirring and mixing process, the adverse effect of the increase in the soil volume due to the injection of the stabilizer is the peripheral soil outside the excavation pipe 2. That is, no ground displacement occurs in the horizontal direction and no adverse effect is exerted on existing structures in the vicinity.

Further, the soil increased by the injection of the stabilizer in the excavation pipe 2 overflows from the excavation hole 10 provided on the ground portion of the excavation pipe 2, and the soil is naturally excavated.

[0013]

EXAMPLE An example of the present invention shown in the drawings will be described below.
FIG. 1 shows the overall structure of a ground improvement device in which an endless track car 13 is equipped with an excavation pipe 2. The excavation pipe 2 is arranged along a leader 15 vertically supported by a base machine 14 of an endless rail car 13, an upper end thereof is connected to a rotary driving device 1 which moves up and down along the leader 15, and a lower portion thereof is constituted by a steady rest 16. It is held vertically.

FIG. 2 shows, in a contracted state, the structural details of the excavating pipe 2 which is constructed so that the outer casing 3 and the inner casing 4 can be expanded and contracted by a structure capable of transmitting a rotational force by a spline as an example. Several earth drain holes 10 are provided at the upper position of the inner casing 4, and a downwardly sharp cutting tooth-shaped casing cutter 5 is provided at the front edge of the outer casing 3.

FIG. 3A is an enlarged view of the lower structure of the drill pipe 2 shown in FIG. As shown in FIG. 3B, a casing cutter face 6 having a structure having a cutting edge 6 ′ on the rotating front edge is fixed to the inner diameter surface slightly above the casing cutter 5 provided at the tip edge portion of the outer casing 3 as shown in FIG. 3B. Further, a hollow shaft 7 is attached substantially vertically upward from the center of the casing cutter face 6. The casing cutter face 6 directly below the hollow shaft 7
A leading cutter 17 is provided at the center of the lower surface of the above, and a stabilizer can be discharged from the portion of the leading cutter 17 when the excavating pipe 2 is normally rotated. Thus, the outer casing 3, the casing cutter face 6, and the hollow shaft 7 are integrated, and the excavation pipe 2 by the rotary drive device 1 is formed.
The casing cutter face 6 and the hollow shaft 7 accompanying the rotation of
Are integrally rotated. Further, a hose 9 for supplying a stabilizer is provided at the upper end of the hollow shaft 7 in the swivel joint 1.
They are connected via 1. Therefore, the stabilizer sent from the slurry plant 18 of FIG. 1 is supplied to the hollow shaft 7 through the hose 9, and the injection holes 12 provided at several positions above and below the hollow shaft 7 and the leading cutter 17 are provided. Can be injected from the location into the soil. Further, the hollow shaft 7 is provided with a plurality of stirring blades 8 disposed between the swivel joint 11 and the casing cutter face 6 in the radial direction at substantially equal intervals in the axial direction of the hollow shaft 7. The hollow shafts 7 are provided integrally with each other.

Next, FIG. 4A shows a state in which the excavation pipe 2 is in an expanded state. 4B to 4E are cross-sectional views of the drill pipe 2 shown in FIG. 4A at positions b, c, d, and e. The excavation pipe 2 has the outer casing 3 as described above.
The inner casing 4 and the inner casing 4 are combined in a telescopic double tube structure, and the male spline 20 is provided sufficiently long in the axial direction of the inner surface of the outer casing 3 (FIG. 4E).
By meshing with the female spline 21 provided as shown in FIG. 4B on the entire outer peripheral surface of the inner casing 4, it is possible to transmit rotational torque and improve smoothness and accuracy of expansion and contraction operation. Further, as shown in FIG. 4D, a male spline 20 is formed on the entire inner peripheral surface of the upper casing of the outer casing 3 as shown in FIG. 4D. This enables the transmission of various torques.

Although not shown in the drawings, the present invention can be implemented as a multi-axis type ground improvement device for excavating by arranging two or more excavating pipes 2 in parallel. Next, an implementation point of the ground improvement method using the ground improvement device configured as described above will be described with reference to FIGS. 5 and 6. Figure 5A
D show the process of advancing the ground improvement of the soft ground by the excavation pipe 2 from the ground to reach a predetermined depth.

First, as shown in FIG. 5A, the endless track car 13 is moved to a position on the soft ground to be improved,
Drill pipe 2 contracted to the shortest state as shown in FIG. 1 or 2.
Is held vertically and is connected to the rotation drive device 1 to rotate the excavation pipe 2 in the normal direction and apply a downward pushing force to vertically penetrate into the soft ground along the leader 15 to advance excavation. As the excavation pipe 2 rotates, the casing cutter face 6 and the hollow shaft 7 integrally rotate in the same direction to excavate the ground soil. At the time of excavation and penetration, a sharp blade-shaped casing cutter 5 provided at the tip edge portion of the outer casing 3 excavates the soft ground in a circular shape. At this time, it is convenient to lubricate the excavation by discharging the stabilizer from the part of the leading cutter 17 (discharging the tip). Since the casing cutter 5 can excavate not only general soil but also hard ground such as a gravel layer or an obstacle in the soil such as a pine pile, escape of the excavation pipe 2 due to the hard ground or an obstacle occurs. Instead, excavation and penetration can be advanced while maintaining high vertical accuracy. Moreover, the soft ground excavated in a cylindrical shape by the casing cutter 5 is subsequently taken into the same excavating pipe 2 while being excavated into pieces by the casing cutter face 6 provided slightly above the tip of the outer casing 3. The excavated soil taken into the excavated pipe 2 by such excavation is further stirred by the stirring blade 8 of the hollow shaft 7 and mixed with the stabilizer injected from the injection hole 12 provided in the hollow shaft 7. Therefore, the ground improvement treatment in the excavation pipe 2 completely isolated from the surrounding ground becomes possible, and the injection pressure by the stabilizer injection and the working pressure at the time of stirring and mixing do not exert any influence on the outside. In addition,
Although illustration is omitted, since the stirring blade 8 has a double structure, it is also preferable to install an inclinometer inside the stirring blade 8 to manage the inclination of the excavation pipe 2 for construction.

FIG. 5B shows a stage in which the excavation and penetration and the ground improvement treatment corresponding to the length of the outer casing 3 have been advanced.
At this time, the upper end of the outer casing 3 and the soil discharge hole 10 of the inner casing 4 are exposed above the ground. At this stage, the rotary drive device 1 is temporarily stopped to stop excavation of the soft ground. The soil, which has been increased in volume by the stabilizer injection due to the excavation infiltration up to this stage and overflowed, is moved up in the excavation pipe 2 and is naturally excavated from the earth removal hole 10 provided at the above-ground portion of the inner casing 4. . Therefore, it is not necessary to remove the soil in advance when the excavation pipe 2 penetrates, and the surrounding ground is not adversely affected at all.

FIG. 5C shows an expanded state of the excavation pipe 2 in which the inner casing 4 is pulled up to the upper limit while the outer casing 3 is left in the soil by pulling up the rotary drive device 1 along the leader 15 from the state of FIG. 5B. Is shown. In this extended state, the spline connection between the lower portion of the inner casing 4 and the upper portion of the outer casing 3 (range a in FIG. 4A) is performed over the entire circumferential surface, and they are locked (see FIGS. 4A and 4D). Next, in FIG. 5D, the excavation pipe 2 extended as shown in FIG. 5C is vertically rotated downward along the leader 15 while rotating again in the forward direction by the rotary drive device 1 to advance the excavation stirring to the deepest portion. Shows the stages. Even during this excavation and stirring, the soil whose volume has increased due to the injection of the stabilizer due to the penetration of the excavation pipe 2 rises inside the excavation pipe 2 and is naturally excavated from the earth removal hole 10. The expandable double pipe structure of the excavating pipe 2 can reliably transmit the rotational torque (excavating stirring torque) by the action of the spline connection. Further, since the expansion and contraction operation can be performed smoothly by maintaining the vertical accuracy by the spline, construction at a large depth can be efficiently performed. A long sliding key or the like can be adopted instead of the spline.

FIGS. 6A to 6C show steps from the deepest excavation state of FIG. 5D until the excavation pipe 2 is pulled to the ground. FIG. 6A shows a state in which the rotary drive device 1 rotates the drill pipe 2 in the direction opposite to the direction in which it penetrates, and while the stabilizer is being injected (pulled out and discharged) from the injection hole 12 of the hollow shaft 7, the stirring and mixing are overlapped and the stretched state is achieved. The excavation pipe 2 is pulled out along the leader 15 until the upper part of the outer casing 3 appears on the ground. Since the surrounding ground is sufficiently stirred, the excavation pipe 2 can be easily pulled out, and the improvement body 22
Is exposed. Next, FIG. 6B shows that the stirring and mixing process by rotating the drill pipe 2 and injecting the stabilizer is once stopped, and the locked state of the spline connection between the inner casing 4 and the outer casing 3 is released, and then only the inner casing 4 is driven to rotate. 1 shows the stage in which it is lowered along with the leader to the shortest contracted state and stored in the outer casing 3. In this contracted state, the outer casing 3 and the inner casing 4 are integrally joined. Finally, FIG. 6C shows a stage in which the excavating pipe 2 is pulled out to the ground along the leader 15 while stirring the soft ground while injecting the stabilizing material while rotating the excavating pipe 2 again in the reverse direction by the rotary drive device 1 again. The improvement body 22 is completely exposed in the trace of pulling out. With above 1
The improvement of the soft ground of the improved body of the book is completed, and thereafter, the same process is repeated over the entire area of the soft ground to proceed the improvement treatment.

[0022]

EFFECTS OF THE INVENTION The ground improvement method and the ground improvement device according to the present invention have the following effects. (1) The casing cutter at the tip of the excavating pipe sharply excavates not only general soil in soft soil but also hard soil such as gravel layer and underground obstacles such as pine piles, so high vertical accuracy is maintained. Excavation processing can be performed. As a result, high quality and high accuracy ground improvement is achieved while maintaining the continuity of the improved ground (improved body). (2) An improved process of stirring and mixing excavated soil and stabilizer in an excavated pipe that is completely isolated from the surrounding ground,
The soil whose volume has been increased by injecting the stabilizer will be naturally discharged by overflowing the excavation pipe into the earth discharge port in the process of stirring and mixing, so there will be no adverse effects such as ground displacement on the surrounding ground and no pollution. The ground improvement of is achieved. (3) Since the excavation pipe has a double-tube structure that can transmit and receive a rotational force and can expand and contract, even if the improvement depth is deep due to the reliable transmission of the rotational torque and the accompanying improvement in accuracy during expansion and contraction. Compared to the conventional replenishment method, the ground can be efficiently improved in a short period of time while maintaining high vertical accuracy.

[Brief description of drawings]

FIG. 1 is a side view showing an overall configuration of a ground improvement device.

FIG. 2 is a sectional front view showing a state in which the excavating pipe is in a contracted state.

FIG. 3 is an enlarged sectional front view of a lower structure of the drill pipe in a contracted state, and B is a bottom view thereof.

FIG. 4A is a partially cutaway front view showing an expanded state of the excavation pipe, and B to E are bb and c- in FIG.
It is sectional drawing of c, dd, and ee line arrow.

5A to 5D are explanatory views showing steps of the ground improvement from the ground to reach a predetermined depth according to the present invention.

6A to 6C are explanatory views showing steps from the deepest reach state to the state where the excavation pipe is pulled to the ground according to the present invention.

[Explanation of symbols]

 5 Casing Cutter 6 Casing Cutter Face 7 Hollow Shaft 8 Stirring Blade 2 Excavation Pipe 1 Rotation Drive Device 9 Hose 10 Earth Discharge Hole 11 Swivel Joint 12 Injection Hole 3 Outer Casing 4 Inner Casing

Claims (3)

[Claims] 1. A ground improvement method for excavating soft ground, injecting a ground stabilizing material or hardening material into excavated soil, and agitating and mixing with the soil to improve the soft ground, wherein a tip cutter is provided with a casing cutter. , A casing cutter face on the inner diameter surface near the tip, and a hollow shaft rising from the center of the casing cutter face is provided with several stages of stirring blades. The ground is excavated by penetrating vertically, and the excavated soft soil soil is agitated by the agitating blade in the excavation pipe, and the ground stabilizer or hardening material supplied through the hose is injected into the soil and mixed. However, the soil of the volume increase due to the injection of the ground stabilization material or the hardening material is left to the ascending inside the excavation pipe, and a plurality of earth removal holes are provided above the excavation pipe. Ground improvement method characterized by natural soil removal from the ground. 2. A ground improvement device for excavating soft ground, injecting a ground stabilizer or a hardening material into excavated soil, stirring and mixing with the soil to improve the soft ground, which is rotated by a rotary drive device. A casing cutter is provided at the tip edge of the pipe, a casing cutter face is fixedly provided on the inner diameter surface near the tip of the drilling pipe, and a hollow shaft that rises from the center of the casing cutter face. Several stages of stirring blades are provided, a hose inserted through an upper end opening of an excavation pipe is connected to a swivel joint provided at the upper end of the hollow shaft, and a plurality of injection holes for a ground stabilizer etc. are provided at the hollow shaft, A ground improvement device characterized in that a plurality of earth removal holes are provided in the aboveground portion of the excavation pipe. 3. The ground improvement device according to claim 2, wherein the outer casing and the inner casing are configured to be expandable and contractible with a structure capable of transmitting a rotational force.