JPS6117969B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of improving the ground by injecting a chemical solution such as cement bacillus into the ground.

BACKGROUND ART Conventionally, a construction method is known in which a self-hardening chemical solution is injected into soft ground and mixed and stirred with the earth and sand constituting the ground to improve the ground. In such conventional methods, water or chemicals are jetted from a nozzle to perform the mixing operation, or a shaft equipped with mechanical stirring blades is rotated, and the mixing operation is performed by the rotational action of the shaft. however,
Mixing by jet injection has very good agitation properties, but has the disadvantage of being relatively expensive due to slow construction speed. On the other hand, mixing work using mechanical stirring blades has the advantages of fast construction speed and low cost construction, but when comparing the strength during actual construction with mixing with a mixer in laboratory tests, the strength is 1/1. It was found that the value decreased by 3 to 1/10.

Therefore, an object of the present invention is to provide a soil improvement method that can perform stirring and mixing with high efficiency when improving the ground using a chemical solution, and can also obtain strong soil.

According to the present invention, the stirring operation using the jet jet and the stirring operation using the stirring blades are performed simultaneously, and the advantages of both operations can be utilized.

Conventional jet injection is generally carried out using water (suspension) or chemical liquid at an ultra-high pressure of about 200 to 500 kg/cm ² and a small flow rate of about 30 to 70 min. The purpose was to cut the ground by cavitation, so it was not very promising for stirring work. However, since the present invention uses jet injection for the purpose of stirring, the pressure is 3 to 50 kg/
cm ² , and the flow rate is low, medium pressure, and large flow rate of 150 to 500/min. The pressure and flow rate of the jet injection according to the present invention are those applied to ordinary fire pump water spraying work, and the impact force and flow force thereof are suitable for stirring. These pressures and flow rates cause the soil to be improved to exceed its liquid limit, fluidize it, and displace soil.
Therefore, the stirring operation can be carried out very suitably.

In addition, in the conventional stirring operation using mechanical stirring blades, an opening is provided at the tip of the auger head, and a large amount of the chemical is discharged vertically downward from the opening with almost no pressure applied. The discharge of chemical liquid does not help in excavating the ground or mixing it with earth and sand. However, in the present invention, a plurality of nozzles are provided on the stirring blade, a member adjacent to the stirring blade, or its rotating shaft, and water or a chemical solution is jetted to weaken the ground to be improved in advance by the jet jetting. Mechanical stirring work can be performed with small rotational torque.

According to an embodiment of the present invention, a bit having a nozzle and a stirring blade is provided at the tip of the pipe, and when the pipe is lowered, that is, when the bit is inserted into the ground, water (suspension) is injected from the nozzle to stir the ground. It performs weakening and stirring, and when pulling up the bit, a chemical solution is injected from the same nozzle to mix and stir.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, in which a pipe 1 having a bit B, which will be described later, at its tip is suspended by a crane 3 via a rotation joint 2, and the pipe 1 is rotatably supported. It is rotatably supported by device 4. Water (suspension) or a chemical solution can be injected into this pipe 1 via a hose 5. Depending on the nature of the ground and construction conditions, the pipe 1 may be pushed into the ground using a device that presses the pipe 1 downward or a three-point pile driver equipped with an auger rotation mechanism. Then, the pipe 1 is lowered into the ground as in the conventional method while being rotated, and then pulled up to form a ground improvement portion indicated by the reference numeral 6 in the ground.

Figures 2 and below show various embodiments of bits for carrying out the invention.

In FIG. 2, a pipe-shaped main body 10 is provided with a communication member 11 connected to the pipe 1 (FIG. 1) at its upper part, and a communication member 12 connected to an earth auger head 13 or a wing-type boring bit at its lower part.
is provided. Rod-shaped wings 14, 15 and 16, 17 extending in opposite directions are provided near the top and bottom of the main body 10, respectively, and a bracket 1 is provided at the bottom of the top wings 14, 15.
8 and 19 are provided with nozzles 20 and 21, respectively, and brackets 22 and 23 provided on the upper portions of the lower wings 16 and 17 are provided with nozzles 24 and 25, respectively. These nozzles 20, 21,
The liquid passages at the center of the main body portion 10 communicate with the liquid passages 24 and 25 via brackets, respectively. Although the direction of each nozzle is arbitrary, it is preferable to create a vortex as shown by the arrows x and y between the upper and lower blades as shown in the figure.

The embodiment shown in FIG. 3 is substantially the same as that in FIG. 2, except that each nozzle is oriented radially outward and a piano wire 26 is used to improve agitation between the upper and lower blades.
are stretched between the upper wings 14, 15 and the brackets 22, 23.

In the example shown in Fig. 4, the upper wings 14 and 15 have frames 2
7 and 28 are provided to enhance the stirring effect, and the nozzles are oriented toward the blades on the opposite side so as to generate a vortex.

Each of the above embodiments is suitable for clay and beet soil.

FIG. 5 shows that the main body 10 is provided with screws 30, 31, and rod-shaped wings 32, 33 are provided in the center radially outward, and the main body 10 and the screws 30,
31 is provided with a plurality of nozzles 34. Wings 3
A piano wire 35 is stretched between 2 and 33 and the upper and lower communication members 11 and 12.

The embodiment of FIG. 6 is substantially the same as that of FIG.
This is an example in which auxiliary wings 36 and 37 are provided between 33 and the lower end of the main body.

The embodiment shown in FIG. 7 is a modification of the embodiment shown in FIG. 6, in which the wings 32a and 33a are provided to be inclined upward.

The examples shown in FIGS. 5 to 7 above are examples suitable for sandy ground. In these embodiments, different liquids may be pumped through the nozzles provided on the screws 30 and 31 and the nozzle provided on the main body 10. All nozzles are provided to spray liquid in the horizontal direction. Especially Screw 3
0 and 31, the position of the nozzle is determined so that even if the main body part 10 moves up and down and rotates, the nozzle is always sprayed continuously over a certain range of the target ground for a certain period of time.

In the embodiment shown in FIG. 8, a nozzle bracket 40 is provided in the middle of the main body 10, fixed blades 41, 42 facing downward are provided near the upper end, and movable wings 43, 42 are provided near the lower end.
44 (44 is not shown). Each wing is angularly shifted by 90 degrees in plan view, and the movable wing can be moved angularly as shown by dotted lines 43a and 44a. (Although the movable blade is not actually provided at the position indicated by the dotted line, it is shown as a dotted line for the purpose of explanation). The nozzle 45 provided on the nozzle bracket 40 has wings 41, 42, 43,
44, so that it is possible to wipe off dirt and dust that has adhered to the wings. Also fixed wings 41, 42
A piano wire 16 is stretched as shown in the figure.

The embodiment shown in FIGS. 9A and 9B is a modification of FIG. 8, in which piano wire is not used and the fixed wings 41a and 42a extend in the horizontal direction. The movable blade 43 can be angularly moved from the position shown in FIG. 9A to the position shown in FIG. 9B.

Figures 10 A, B, C, and D show an embodiment in which movable blades are provided as shown in Figures 8 and 9 A and B, where A shows the movable blade raised, and C shows the movable blade raised. The protruding parts are shown, and B and D are views seen in the directions of arrows B and D.

A liquid passage 50 is formed in the center of the main body part 10, and is injected as a jet stream 52 from a lower opening 51 to help penetrate the bit into the ground. A valve 54 for opening and closing the liquid path 50 is provided at the base of the movable blade 53, and is configured to close during pulling up at the penetration time. In the figure, 55 and 56 are stoppers for the movable blade 53, 57 is a fixed blade, and 58 is a nozzle.

Now, when the bit penetrates, the main body part 10 descends, so the movable blade 53 faces upward as shown in FIG.
4 is open. The liquid flowing through the liquid path 50 is then injected from the lower opening 51. When pulling up the pipe, as the main body 10 rises, the movable blades 53 become horizontal as shown in FIG.
engage with. At this time, since the valve 54 is closed, the liquid does not flow downward, but is injected from the nozzle 58.

When implementing the present invention, the earth auger head 1
3 does not necessarily need to be boiled, and bit B
You may connect multiple numbers. At this time, the bit B may be the same or different, and may be selected as appropriate depending on the ground to be improved.

Further, a plurality of liquid channels may be provided in the pipe 1 and the bit B, and water, air, and chemical liquid may be injected simultaneously or intermittently.

Referring again to FIG. 1, an embodiment of the present invention will be described.

First, water (suspension) is supplied from the hose 5, and while the pipe 1 is rotated by the rotation support device 4, the pipe is lowered by the crane 3. Then, Bit B gradually descends while stirring the ground and reaches a predetermined position. Once the predetermined position is reached, a chemical solution such as cement bacillus slurry is supplied to the hose 5, and the pipe 1 is
Pull up while rotating. As a result, the chemical solution is properly stirred and mixed, and the ground is improved extremely well.

In conventional ground improvement methods, the moisture content of the ground is lowered through consolidation, dewatering, etc., as seen in vertical drain and quicklime trench methods, but in the present invention, contrary to the conventional techniques, It increases the moisture content of the ground by supplying a large amount of water or chemical solution into the ground. By increasing the water content ratio in this way, the same effect as in the mixing operation in a mixer can be obtained in a short time. Therefore, the chemical solution is used in the form of a slurry using an activated alumina source, a gypsum source, and a lime source like cement bacillus material. With such a chemical solution, even if a large amount of moisture is present in the ground, ettringite is produced and the ground can be chemically solidified.

The water or chemical solution is ejected from the nozzle continuously at a certain location for a certain period of time, but may be ejected intermittently. Generally, the chemical solution may be a self-hardening agent capable of producing ettringite, but a foaming agent may be added if necessary.

[Brief explanation of the drawing]

Figure 1 is a side view for explaining the construction method according to the present invention, Figures 2, 3, 4, 5, and 6.
7 and 8 are respectively side views showing an embodiment of the bit, and FIG. Figure B is a side view showing where the movable blade is lifted, Figure 10 is a side view showing the movement of the movable blade, A is a side view showing the position of the movable blade when the bit is penetrated, and B is a side view showing the position of the movable blade when the bit is penetrated. C is a side view showing the position of the movable blade when pulling up the bit, and D is a side view seen in the direction of arrow D in C. B...bit, 1...pipe, 3...crane, 4...rotation support device, 5...hose, 6...
Ground improvement part, 10...Main part, 14, 15, 1
6, 17, 32, 33, 32a, 33a, 41,
42, 41a, 42a, 57... wing, 43, 4
4, 53...Movable wing, 20, 21, 34, 45,
58... Nozzle.

Claims (1)

[Claims] 1 Prepare a bit with stirring blades and a nozzle, attach the bit to a pipe, and while rotating the bit, inject water from the nozzle at a pressure of 3 to 50 kg/cm ² and a flow rate of 150 to 500/min, and insert it into the ground. Then, the ground is fluidized to a state exceeding its liquid limit, and after reaching a predetermined position, a chemical solution is injected from a nozzle.The chemical solution is self-hardening and produces ettringite even in a large amount of moisture. A ground improvement method characterized by pulling up bits while rotating and mixing them with jets from a nozzle and stirring blades.