JPS6251329B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground improvement method and apparatus, particularly to a ground improvement method and apparatus useful for improving soft ground.

The applicant first inserts a guide casing into the ground under the guidance of the tip bit, and when the insertion reaches a predetermined depth, inserts an arm equipped with a chain cutter that can be freely stored and extended into the casing into the ground. As the cutter rotates, the casing extends into the ground from the stored state at the time of insertion, and then continues to rotate the cutter to disturb the ground and gradually pull the casing out of the ground.At the same time, the jet formed on the arm and tip bit We proposed a device that improves the ground by injecting a liquid (grout) into the disturbed ground through a hole (see, for example, Japanese Patent Publication No. 54-32531). This ground improvement device can improve the ground stably and reliably over a certain width without being affected by the soil quality, and improves the soil quality better than conventional methods such as jet grouting, which inject liquid directly into the ground. It is excellent in that ground improvement can always be carried out stably and reliably over a certain width without being affected. However, this type of equipment has a narrow construction width equivalent to the width of a chain cutter, so when it is applied to ground improvement over a wide width such as soft ground or a wide area range, the construction width becomes too small. The narrowness inevitably caused problems in terms of work efficiency, making it unsuitable for such uses.

The present invention has been made with the aim of solving such problems, namely, the present invention provides a method for installing guide rods in the ground that is to be improved.
The rod is inserted by drilling guidance by the rotation of the tip bit provided at the lower end of the rod and the overhanging arm cutter provided at the bottom of the rod, and then, when the insertion reaches a predetermined depth, the rotation of the tip bit and arm cutter is performed. While continuing to rotate, the arm cutter is revolved to mechanically disturb the ground within the revolution radius, and while continuing this mechanical disturbance, a liquid agent is spouted from the tip bit and the nozzle hole of the arm cutter into the disturbed ground. A ground improvement method characterized in that the rod is pulled up from within the ground together with an attached tip bit and an arm cutter, a guide rod inserted into the ground for the purpose of improvement, and the lower end of the rod. The rod is equipped with a tip bit that is rotatable on its own axis and an overhanging arm cutter that is provided at the bottom of the rod so that it can rotate freely on its axis and revolve around the rod, and the rod is provided with a tip bit and an arm cutter that can be rotated on its axis by operating the tip bit and arm cutter from the ground. and a drive device for rotating the arm cutter by operating it on the ground, and the tip bit and the arm cutter are further provided with a nozzle hole that is connected to a liquid pumping section installed on the ground through the rod. The present invention relates to a ground improvement device characterized in that it is provided with a ground improvement device.

According to the ground improvement method and device of the present invention, when the guide rod is pulled up from within the ground, the ground within the revolution radius of the overhanging arm cutter is mechanically disturbed by the rotation and revolution of the arm cutter, and the ground is disturbed within the disturbed ground. Since it is a method in which the liquid is sprayed out over a wide range of areas, one-time construction can improve the ground over a wide area with a radius equal to the width of the arm cutter, making a significant contribution to improving construction efficiency. .

Below, a description will be given of a ground improvement device suitable for carrying out the ground improvement method of the present invention and a case where the method of the present invention is implemented using the device.

The ground improvement device shown in FIG. 1 is composed of inner and outer double pipes 1a and 1b that can be rotated individually by a guide rod 1 operated on the ground.A tip bit 2 is attached to the lower end of the inner pipe 1a of the guide rod 1. Further, an overhanging arm cutter 3 is provided at the lower part via a rotation transmission mechanism 4 about the central axis, and the overhanging arm cutter 3 extends outward through the outer tube 1b. In addition, the overhanging arm cutter 3 and tip bit 2 are each filled with a liquid (grout agent).
The nozzle holes 3a and 2a are provided with the nozzle holes 3a and 2a, and the nozzle holes 3a and 2a are connected to the arm cutter 3 and the tip bit 2.
The passages 3a ₁ , 2a ₁ formed in the same passages, 3a ₁ ,
It is connected to the liquid agent pumping unit ₅ installed on the ground through a passage 1b 1 formed in the outer pipe _1b so as to communicate with the passage 1b ₁ and a passage 1a ₁ in the inner pipe 1a that communicates with the passage 1b 1. The rotation transmission mechanism 4 includes a bevel gear 4a fitted to the lower end of the inner tube 1a, a bevel gear 4b fitted to the shaft portion 3b of the arm cutter 3 so as to mesh with the bevel gear 4a, and the bevel gear 4b. A combination of bevel gears 4c fitted onto the shaft portion 2b of the tip bit 2 so as to mesh with each other is shown. Others In the figure, 6 is a bearing for rotatably supporting the inner tube 1a with respect to the outer tube 1b, 7 is a bearing for rotatably supporting the shaft portion 2b of the tip bit 2 with respect to the outer tube 1b, 8 is a bearing provided on the arm cutter 3. In the present invention, it is not necessary to necessarily provide two overhang arm cutters 3 as shown in the drawings, but it is sufficient to have at least one.

When carrying out the soil improvement method according to the present invention using the soil improvement device shown in FIG. 1, a boring machine such as the one shown in FIGS. A
is used. This boring machine A has first and second rotation drive mechanisms that rotate the inner and outer tubes 1a and 1b of the guide rod 1 while holding them individually.
The rotary drive mechanisms _{a 1 and} a ₂ are provided on an elevating member _d that is moved up and down along a guide rail c by an elevating device b.

Figure 2 shows the situation at the start of construction, and in the state shown in Figure 2, the inner pipe 1a is rotated by the first rotary drive mechanism _a1 .
When rotation is applied to , this rotation is transferred to the rotation transmission mechanism 4
The power is transmitted to the overhanging arm cutter 3 and the tip bit 2 via the arm cutter 3 and the tip bit 2, which are rotated around the central axis (rotation). In the state shown in FIG. 2, the second rotational drive mechanism _a2 is in a non-driving state, and the outer cylinder 1
b is not rotated, so the arm cutter 3 only performs automatic rotation.

In the state shown in FIG. 2, when the elevating member d is lowered along the guide rail c via the elevating device b, the tip bit 2 and the overhanging arm cutter 3 move vertically along the ground as they descend. A hole is drilled and the guide rod 1 is inserted and guided into the ground.

As shown in Figure 3, when the insertion into the ground reaches a predetermined depth, while the inner tube 1a continues to rotate, the other drive device _a2 is driven to give rotation to the outer tube 1b. Then, the overhanging arm cutter 3 that is penetrated by this rotates around the outer tube 1b together with the outer tube 1b, starts revolving, and disturbs the ground within the orbital radius. Therefore, the tip bit 2 and the nozzle hole 2 of the arm cutter 3 are located in the disturbed ground within this orbital radius.
Guide rod 1 while spouting liquid from a and 3a.
By gradually pulling upward, the ground within the orbital radius can be improved all at once. When pulling up guide rod 1, arm cutter 3
If there is an obstacle buried in the ground that obstructs the revolution of the arm cutter 3, the rotation of the outer tube 1b is stopped until the arm cutter 3 passes the obstacle, and the revolution of the arm cutter 3 is stopped. Only the rotation may be continued.

FIG. 4 shows another example of the ground improvement device applied to the implementation of the construction method of the present invention.

As shown in detail in FIG. 4, in this device, the guide rod 11 is composed of a fixed outer tube 11a and a rotating inner tube 11b that is rotated by external operation, and the lower end of the fixed outer tube 11a An upper guide casing 12 is integrally connected to the upper guide casing 12, and a lower casing 13 is connected to the lower end of the rotating inner pipe 11b via a clutch mechanism 17 and a first rotation transmission mechanism 16, which are engaged and released as appropriate by ground operation. ing. In the figure, 14 is a bearing for the lower casing 13.

The illustrated first rotation transmission mechanism 16 includes an external gear 16 that is supported by the upper guide casing 12 via a bearing 18 while being fitted into the inner rotation tube 11b.
a, an internal gear 16b formed on the inner circumferential surface of the upper guide casing 12 and a shaft 16c' implanted in the lower guide casing 13, which meshes with the inner and outer gears 16a and 16b while being fitted on the shaft 16c'; Small gear 1
6c, and the small gears 16c can be provided at three locations at 120° intervals, for example, as shown in FIG. The number of small gears 16c is not particularly limited. On the other hand, the clutch mechanism 17
It consists of a spline 17a formed on the top and a groove 17b formed on the inner peripheral surface of the external gear 16a so as to be engaged with and disengaged from the spline 17a. No transmission occurs, and as shown in FIG. 4, by pulling up the rotating inner tube 11b and engaging the spline 17a with the groove 17b of the external gear 16a, the rotation of the rotating inner tube 11b is transferred to the lower guide via the first rotation transmitting mechanism 16. The signal is transmitted to the casing 13. In the figure, reference numeral 19 denotes a stopper for regulating the position provided on the rotating inner tube 11a, and the stopper 19 is located at the pull-up position (clutch engagement) and push-down position (clutch disengagement) of the rotating inner tube 11b, respectively. It is designed to abut against stepped portions 20, 20' on the inner peripheral portion of 12.

As described above, the lower guide casing 13 receives the appropriate rotational force from the rotating inner tube 11b through the second rotation transmission mechanism 21, and rotates on its own axis. During rotation, at least one arm cutter 22 extending outward revolves around the casing 13 while continuing to rotate.
and the same rotation inner tube 1 via the third rotation transmission mechanism 23.
Tip bit 24 rotates by receiving rotational force from 1b
are provided for each.

In the embodiment shown in the figure, two arm cutters 22 are provided at an interval of 180° with respect to the lower guide casing 13, and an arm shaft 22a connecting the cutters is arranged so as to cross the lower guide casing 13. Penetrating. Therefore, when the lower guide casing 13 rotates, the arm cutter 22 revolves around the lower guide casing 13 together with the lower guide casing 13. Further, the arm shaft 22a is connected to the rotating inner tube 11b.
A pair of bevel gears 21 constituting the rotational transmission mechanism 21
a, 21b, and thus the shaft 22a
The arm cutter 22 connected by is rotated by the rotating inner tube 11b. In addition, rotating inner tube 11
The bevel gear 21a on b is the lower guide casing 13
The rotating inner tube 11b is supported through a bearing 25, and in this supported state is connected to the rotating inner tube 11b through a spline mechanism 26. This spline mechanism 2
6 is necessary for moving the rotating inner tube 11b up and down to engage and disengage the clutch mechanism 17, and this spline mechanism 26 always maintains an engaged state regardless of the up and down movement of the inner tube 11b. The dimensions are set as follows. On the other hand, the tip bit 24 is connected to the rotating inner tube 1 via the bevel gear 23a on its shaft 24a and the bevel gears 21a and 21b linked thereto.
1b, and these constitute a third rotation transmission mechanism 23 for the tip bit 24.

The arm cutter 22 and tip bit 24
has passages 27 and 28 for the liquid agent (grout material) and injection holes 29 and 30, and these passages 27 and 28 are connected to the upper and lower guide casings 12 and 13, respectively.
Liquid agent passages 31 and 32 provided in
3, it is connected to a liquid supply unit 34 installed on the ground. In the present invention, the fixed outer tube 11 and the rotating inner tube 11b are structured so that they can be joined as appropriate, and in the figure, 15a and 15b indicate the joints, respectively.

When carrying out ground improvement using this device, the rotating inner pipe 11 should be fixed while the fixed outer pipe 11 is fixed.
In order to give rotation to b, for example, FIGS. 6 and 7
A boring machine A′ as shown in the figure is used. This machine A' is equipped with a clamp mechanism a' that grips the fixed outer tube 11 and a rotation drive mechanism b' that rotates the rotating inner tube 11b. ) is provided on a movable member d' that is moved up and down along a fixed guide c'.

FIG. 6 shows the situation at the start of construction. At the start, the clutch mechanism 17 is disengaged as shown in FIG.
Only the rotation of the arm cutter 22 connected via the rotation transmission mechanism 21 and the rotation of the tip bit 24 connected via the rotation transmission mechanism 23 are performed, and the lower guide casing 13
The rotation of the arm cutter 22 and the revolution of the arm cutter 22 are not performed.

When the device is lowered through the movable member d' in the state shown in FIG. 6, the arm cutter 22 and the tip bit 24 vertically drill holes in the ground as it descends, thereby lowering the device into the ground. I'll guide you through the insertion. By repeating such lifting and lowering of the movable member d' and adding the fixed outer tube 11a and the rotating inner tube 11b each time, the device can be inserted into the ground to a predetermined depth, as shown in Fig. 7. .

Next, in the state shown in FIG. 7 (the clutch mechanism 17 is disengaged), the fixed outer tube 11 is released from the clamp mechanism a', and then the movable member d' is raised to open the rotating inner tube 11b. When pulled up, clutch mechanism 1
After the clutch mechanism 17 is engaged, the fixed outer tube 11a is again clamped by the clamp mechanism a' to maintain this engaged state.

When the rotating inner tube 11b is rotated with the clutch mechanism 17 engaged, the tip bit 24 and the arm cutter 22 rotate on their own axis, and the lower guide casing 13 rotates from the rotating inner tube 11b via the rotation transmission mechanism 16. Since the arm cutter 22 is rotated by the force, the arm cutter 22 extending from the arm cutter 22 revolves around the lower guide casing 13. The state of this revolution is shown in imaginary lines in FIG.

In this state, if the device is gradually pulled upward, the ground will be disturbed over a wide area with the radius of the extension width of the arm cutter 22 as the arm cutter 22 rotates and revolves. By injecting and filling the disturbed ground from the injection holes 29, 30 of the arm cutter 22 and the tip bit 24 in parallel with the disturbance of the ground, the ground within the revolution radius can be improved all at once.

As described above, according to the present invention, it is possible to easily insert the device to a predetermined depth in the ground by drilling guidance based on the rotation of the tip bit and the arm cutter, and after the device is inserted to the predetermined depth, the rotation and revolution of the arm cutter are controlled. This makes it possible to improve the ground over a wide area whose radius is the width of the overhang of the cutter. For example, as shown in Figure 8, if such a ground improvement section is continued in a series, it is possible to improve the ground with a large thickness. It is possible to form a continuous wall, and by combining multiple rows by shifting them by half a pitch as shown in Figure 9, it is possible to achieve the purpose of ground improvement over a wide area, especially for continuous underground walls with a large thickness such as soft ground. It is extremely useful for applications such as wall formation and ground improvement over a wide area.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of essential parts showing an example of equipment suitable for carrying out the construction method of the present invention, and Figs. 2 and 3 are
Fig. 1 is an explanatory diagram showing a situation in which the construction method of the present invention is implemented using the equipment shown in the invention, and Fig. 4 is a vertical cross-section of the main part showing yet another example of equipment suitable for implementing the construction method of the invention. 5 is a cross-sectional plan view of the first rotation transmission mechanism in FIG. 4, and FIGS. 6 and 7 show the construction method of the present invention carried out using the apparatus shown in FIG. 4. 8 and 9 are plan views showing the situation of the ground improvement section obtained by the construction method of the present invention. In the figure, 1 and 11 are guide rods, 2 and 24
is the tip bit, and 3 and 22 are the arm cutters.

Claims (1)

[Claims] 1. A guide rod is placed in the ground for the purpose of improvement,
The rod is inserted by drilling guidance by the rotation of the tip bit provided at the lower end of the rod and the overhanging arm cutter provided at the bottom of the rod, and then, when the insertion reaches a predetermined depth, the rotation of the tip bit and arm cutter is performed. While continuing to rotate, the arm cutter is revolved to mechanically disturb the ground within the revolution radius, and while continuing this mechanical disturbance, a liquid agent is spouted from the tip bit and the nozzle hole of the arm cutter into the disturbed ground. A ground improvement method characterized in that the rod is gradually pulled up from within the ground together with the attached tip bit and arm cutter. 2. A guide rod to be inserted into the ground for the purpose of improvement, a tip bit provided at the lower end of the rod to be able to rotate freely on its axis, and an overhanging arm cutter provided at the lower part of the rod to be able to rotate freely on its axis and around the Earth, The rod is equipped with a drive device for operating the tip bit and arm cutter on the ground to rotate it, and a drive device for rotating the arm cutter by operating it on the ground. The ground improvement device is characterized in that it is provided with a nozzle hole that is connected to a liquid agent pumping section installed on the ground through the rod.