JPH079097B2 - Soft ground improvement method and its equipment - Google Patents

Description

The present invention relates to a method for improving soft ground and an apparatus therefor.

[Prior Art] In the conventional soft ground improvement method, a soil cement column is formed inside an outer cylinder propelled underground, and then the outer cylinder is pulled up to the ground to improve the ground by the soil cement column. However, even in the soft ground, there is a problem that the hardening agent and the sludge are not sufficiently mixed in the ground improvement of the sludge layer and sufficient strength cannot be obtained because the soil cement column is not sufficiently compacted.

[Problems to be Solved by the Invention] The present invention is a method suitable for improving the ground of a sludge layer by forming an underground pillar having sufficient strength by forming a prepact press column in which sludge and a curing agent are sufficiently mixed. And to provide a device.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention has an outer cylinder provided with a cutting blade at the lower end and an inner pipe provided with a hardener outlet and a screw plate at the lower end, which are opposite to each other. Rotating in the direction and pouring out the hardening agent from the pouring outlet, propelling the mud on the screw plate and the hardening agent into the ground while stirring and mixing, and then propelling while keeping the outer cylinder at the specified position. Rotate in the direction opposite to the time, and in that state the inner pipe is raised by the rotation of the screw plate while applying its own weight to the lower surface of the screw plate by rotating the inner pipe in the direction opposite to the time of propulsion, Soft ground improvement method characterized by pressurizing and compacting the mud / hardener mixture under the lower surface into an outer cylinder, and then raising the outer cylinder to the ground. The outer cylinder and the curing agent spout and In an excavator in which a forward and backward rotatable inner pipe provided with a clew plate is slidably supported by upright guides, and the outer cylinder and the inner pipe rotate in opposite directions, the screw plate A plurality of stirring blades projecting from the upper inner tube of the above, and the bases of the plurality of undulating stirring blades are pivotally attached to the inner surface of the outer cylinder by pins, and the undulating stirring blades support the pins during forward rotation of the outer cylinder. As the center, it stands up in the direction toward the inner pipe due to the resistance of the mud, and when the outer cylinder reverses, it is formed so as to fall down on the inner surface side of the outer cylinder around the pin due to the resistance of the mud. It consists of a soft ground improvement device that is formed so as to enter the ground during propulsion.

"Action" Therefore, the outer cylinder 2 and the inner pipe 5 are in mutually opposite directions (arrows a and b).
And the outer tube 2 and the inner tube 5 when they are simultaneously rotated and propelled into the ground.
Spins are offset and propelled straight downward by the rotation of the screw plate 4 without lateral shake, and the mud and the pouring agent are stirred blades 7, 7 on the screw plate 4 and the stirring blades 8 standing upright in the horizontal direction. By the reciprocal rotation of 8, the mixture is agitated and mixed remarkably. When the lower ends of the outer tube 2 and the inner tube 5 reach a predetermined level position, the propulsion and the pouring of the curing agent are stopped, and the outer tube 2 is stopped.
Is rotated in the direction opposite to the arrow a (arrow a ') at that level position, and when the inner pipe 5 is rotated in the direction opposite to the arrow b (arrow b'), the screw plate 4 rises in the spiral direction. Then, in order to lift and raise the inner pipe 5, the agitated mixture in the outer cylinder 2 is pressed by the lower weight of the screw plate 4 by the own weight of the inner pipe 5 to rise while compacting in the outer cylinder 2. After the inner pipe 5 is lifted to the ground in this way (Fig. 4), when the outer cylinder 2 is pulled up by a crane, the compacted pre-pact press column 10 in the outer cylinder 2 remains in the ground, The ground is improved by the Pact Press Pillar 10. The pumice stone 11 that appears during propulsion is cut by the cutting blade 1 of the outer cylinder 2 to form a cutting hole.

[Example] A cutting blade 1 for cutting a boulder 11 is provided at the lower end of a large-diameter outer cylinder 2,
This is supported by a feeder 12 that moves up and down along an upright guide 6 provided on the machine base such that it can rotate forward and backward. Also this outer cylinder 2
At the lower end of the inner pipe 5 arranged at the center of the pipe, there is provided a hardening agent pouring port 3 such as cement milk and a screw plate 4, which can be rotated forward and backward by a feeder 12 'which can be moved up and down along the guide 6. The ground excavating device is constructed by supporting and forming the outer cylinder 2 and the inner pipe 5 in opposite directions by driving reduction motors 13 and 13 '. The above feeder 12,
12 'is raised and lowered by winding and unwinding the wire ropes 15 and 15' wound on the pulleys 14 and 14 ', respectively.
The 12, 12 ', the outer cylinder 2 and the inner pipe 5 can be raised and lowered. In this inner tube 2, a plurality of stirring blades 7, 7 are laterally projected above the screw plate 4, and the screw plate 4 and the blade 7 are provided.
And a plurality of lateral undulating stirring blades 8 and 8 are disposed between the blades 7 and 7 and the base portions of the blades 8 and 8 are bent at right angles to form a bent portion 8 ′ on the inner surface of the outer cylinder 2. When it is pivoted in the horizontal direction by means of 9, it is raised toward the inner pipe 5 by the resistance of the mud to agitate when it rotates in the direction of arrow a in FIG. 2 falls on the outside of the screw plate 4 due to the resistance of the mud to the position shown by the phantom line in FIG. Of course, the spiral direction of the screw plate 4 is the direction in which the inner pipe 5 enters the ground when the inner pipe 5 is propelled downward. In addition, the reference numeral 16 in the figure indicates the tip cutting blade of the screw plate 4, 17, 1
7'is the guide shoes of the feeders 12 and 12 ', and 18 is the ground.

[Advantages of the Invention] Since the present invention is based on the method and apparatus described above, it is possible to obtain a columnar body having a relatively large strength, which is sufficiently mixed with mud and a hardening agent in a soft ground such as a sludge layer and is sufficiently compacted. It has the effect of being applicable to the improvement of extremely soft ground that can be formed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a soft ground improvement device of the present invention, FIG. 2 is a plan view taken along the line AA of FIG. 1, FIG. 3 is an overall front view of the device, and FIG. FIG. 5 is a longitudinal sectional view of the previous state, and FIG. 5 is an enlarged front view showing a screw plate according to another embodiment. 1 ... Cutting blade, 2 ... Outer cylinder, 3 ... Hardener spout, 4 ...
… Screw plate, 5 …… Inner tube, 6 …… Upright guide,
7 ... stirring blade, 8 ... undulating stirring blade, 9 ... pin.

Claims (2)

[Claims] 1. An outer cylinder having a cutting blade at the lower end and an inner tube having a hardener outlet and a screw plate at the lower end are rotated in opposite directions and the hardener is poured out from the outlet. After propelling the mud on the screw plate and the curing agent into the ground while stirring and mixing, the outer cylinder is rotated in the opposite direction to the propelling while keeping the outer cylinder at the predetermined position, and the inner pipe in that state Is rotated in the direction opposite to that during propulsion to raise the inner tube by rotating the screw plate while applying its own weight to the lower surface of the screw plate, and the mud / hardener mixture under the lower surface is placed in the outer cylinder. A method for improving soft ground, characterized by pressurizing and compacting the outer cylinder and then raising the outer cylinder to the ground. 2. A forward / reverse rotatable outer cylinder having a cutting blade at the lower end and a forward / reverse rotatable inner tube provided with a hardening agent spout and a screw plate at the lower end slide on an upright guide. In an excavator which is freely supported, and in which the outer cylinder and the inner tube rotate in mutually opposite directions, a plurality of stirring blades are projectingly provided on the upper inner tube of the screw plate, and a plurality of stirring blades are formed on the inner surface of the outer cylinder. The base of the undulating stirring blade is pivotally attached by a pin, and the undulating stirring blade stands up in the direction toward the inner tube due to the resistance of the mud when the outer cylinder is propelled by the forward rotation of the outer cylinder, and when the outer cylinder is reversed, the mud is rotated. The soft ground improvement device is formed on the inner surface side of the outer cylinder so as to fall down around the pin, and the spiral direction of the screw plate is formed so as to enter the ground when the inner pipe is propelled.