JPH02304114A - Ground improving method and drilling unit used therefor - Google Patents

Abstract

PURPOSE:To facilitate improvement of ground in a narrow place by passing a flexible hose having a liquid jet at the forward end portion through a substantially L-shaped guide pipe disposed in a longitudinal hole digged in the ground, and letting out same while being rotated. CONSTITUTION:A substantially L-shaped guide pipe 70 formed by uniting a back plate 71 and a base plate 72 into one body is disposed in a longitudinal hole 61, and a high pressure flexible hose 10 is inserted therethrough. A ground improving apparatus 80 is disposed in a suitable place, and the trailing end of the high pressure flexible hose 10 is connected to the apparatus to be first connected to a high pressure water supply source and a compressed air source. The flexible hose 10 is bend and put in the substantially L-shaped guide pipe 10, and the forward end member 13 of the flexible hose 10 is let out in a portion below a pipeline 75, which is a ground portion to be reinforced and advanced substantially in the horizontal direction. When the forward end member reaches the deepest portion, the supply of high pressure water and compressed air is stopped, and a grout material supply source is connected to the hose.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a ground improvement method for improving soft ground beneath railway decks, pipelines, etc., and an excavation device used in this method, and particularly relates to The present invention relates to a ground improvement method that can be used even in a narrow place where equipment for implementing the method is installed, and to an excavation device used in this method.

(Prior Art and Problems to be Solved by the Invention) Conventionally, it has been widely practiced to lay a reinforced concrete railway deck at the top of the uphill heap. Here, after laying the roadbed, IIt
'If the soil is found to be weak and requires reinforcement,
Conventionally, grout injection using vertical poling (chemical injection method) was common. However, grout injection using vertical poling requires drilling holes in the reinforced concrete roadbed, which is a troublesome work, and the holes formed in the reinforced concrete roadbed cause corrosion of the reinforcing bars, which can lead to deterioration of the reinforced concrete roadbed. There was a risk of this happening.

On the other hand, it is also possible to inject the grout material by horizontal poling, but horizontal poling requires a wide area in the horizontal direction for construction, and if the injection location is deep, a large excavation hole is required). It is necessary to have free space on the land, and if there is not enough free space, construction will not be possible.

The present invention has been made in view of two points: a ground improvement method that does not require a small space for installing construction equipment, and which can reliably inject grout in a substantially horizontal direction into the ground area that requires improvement; The purpose is to provide drilling equipment used in the construction method.

(Means for Solving the Problems) In order to achieve the above object, the construction method of the present invention is to excavate a vertical hole in the ground, arrange an abbreviated guide pipe in the vertical hole, and connect a liquid injection port to the tip. Pass a flexible hose provided in the above-mentioned abbreviation-shaped guide pipe in advance or after arranging a vertical hole, and keep the tip side of the flexible hose approximately horizontal with the abbreviation-shaped guide pipe, and rotate the flexible hose on the ground. After the flexible hose is fed out into the ground and the mud in the ground is discharged by injecting high pressure water from the liquid injection port, the flexible hose is pulled out from the ground while being rotated while injecting grout material from the liquid injection port. This is a characteristic feature.

Furthermore, the excavation equipment used in the construction method of the present invention transmits the rotation of the vertical axis to an endless band provided with a large number of excavation blades on the outside via a transmission mechanism, and the rotation of the endless band creates a vertical hole in the ground. The configuration is such that it forms.

(Function) In the present invention, an abbreviated guide pipe is arranged in a vertical groove corresponding to the grout phase injection depth, and the flexible hose can be fed out and rotated approximately horizontally with respect to the ground portion to be reinforced. Then, by jetting high-pressure water from the liquid jetting port installed at the tip of the flexible hose (combined with air jetting if necessary), the muddy part of the ground to be reinforced can be discharged as muddy water, and grout can be filled into the voids created after discharge. The work is completed by filling and solidifying the material and reinforcing the ground. The device that rotates the flexible hose can be placed in an appropriate position by taking advantage of the flexibility of the flexible hose, and can be installed even in narrow spaces around railway roadbeds.

(Embodiments) Hereinafter, embodiments of the ground improvement method according to the present invention and the excavation equipment used in this method will be described with reference to the drawings.

First, the excavation equipment used in the ground improvement method will be explained with reference to FIGS. 1 to 4. In these figures, 30 is a gear case which also serves as a device frame, and a vertical shaft 31 is rotatably attached to the gear case 30 through bearings 32 and 33. This vertical shaft 31 is a boring rod that receives rotational driving force from a boring machine. The vertical axis 31
A bevel pinion 34 is fixed to the lower end of the shaft 35, and the bevel pinion 34 meshes with a bevel gear 36 fixed to a horizontal shaft 35. The horizontal shafts 35 and 37 are supported by the gear case 30 in parallel to each other, and spur gears 38 and 39 that mesh with each other are fixed to each other.

Both ends of the horizontal shaft 37 protrude from the gear case 30,
A chain wheel 40 is fixed to each of the protruding parts. Also, from gear case 30, turnbuckle 4
An excavation shaft 43 is supported parallel to the horizontal shaft 37 by bearings 42 mounted at a predetermined distance apart from each other. Chain wheels 44 are also fixed to both sides of this excavation shaft 43.

A chain 52 (constituting an endless band) having a flat plate 51 to which a plurality of excavating blades 50 are attached on the outside is stretched between the chain wheels 40 and 44.

The turnbuckle 41 is used to appropriately adjust the length of the chain 52 so that it does not loosen.

The remaining part of the excavation shaft 43 provided with the chain has a fourth
As shown in the figure, a large number of excavation blades 53 are directly attached. A carbide tip 54 is attached to the tip corner of this excavation blade 53.
is taken by τj. Note that a carbide tip is similarly fixed to the excavation blade 50.

A water pipe 55 that opens to the outside of the gear case is connected to the lower end of the vertical shaft 31, so that water can be supplied to the excavated part through the vertical shaft 31 (usually using a hollow boring rod) during excavation. ing.

The excavation equipment shown in FIGS. 1 to 4 rotates the horizontal shaft 37 through the transmission path of the bevel binion 34, bevel gear 36, and spur gear 38, 39 by rotating the vertical shaft 31 with a boring machine, and the chain 52 is rotated. It is possible to run the excavation shaft 43 and rotate the excavation shaft 43. Then, the ground can be excavated by the movement of the excavating blade 50 provided on the chain side and the excavating blade 53 on the excavating shaft 43 side to form a vertical hole having a substantially rectangular planar shape. Note that if the vertical shaft 31 is rotated in the same direction, there is a risk that the horizontal shaft 37 and the excavation shaft 43 will gradually shift in the rotation direction, so the vertical shaft 31 is rotated in combination with left and right rotation.

5 to 7 show a ground improvement device for improving the ground by rotationally driving a flexible hose. In these figures, 1 is a device 7 frame, and an electric motor (reduction motor) 2 and a stepless reduction gear 3 are installed and fixed on the 7+/- frame. Further, a hollow metal pipe shaft 5 is rotatably supported by a bearing 4 fixed on the frame. Then, the rotation of the electric motor 2 is transmitted to the stepless reducer 3, and the rotation reduced to about 25 times per minute or less by the stepless reducer 3 is transmitted to the sprocket 6 fixed to the reduction shaft of the stepless reducer 3. , a chain 7, and a sprocket 8 fixed to the pipe shaft 5. The chain 7 is stretched between the sprockets 6 and 8.

A rear end of a high-pressure flexible hose 10 made of rubber or the like is airtightly connected to one end of the hollow metal pipe shaft 5, and a liquid injection port 11 is provided at the tip of the flexible hose 10 as shown in FIG.
and a tip member 13 provided with an air injection port 12 are airtightly connected. One liquid injection port 11 is arranged on the tip surface and one on the side surface (however, the injection direction is slightly forward). Further, the air injection port 12 is provided with a check valve formed by a steel ball 14 and a spring 15, and is closed except when air is injected. An air supply swivel 16 and a liquid supply swivel 17 are attached to the other end of the pipe shaft 5, and the liquid injection port 11 and the liquid supply swivel 17 are connected to a small diameter flexible hose that passes inside the flexible hose 10. 18, and the air injection port 12 and the air supply swivel 16 communicate with each other through the interior space of the pipe shaft 5 and the flexible hose 10.

The liquid supply swivel 17 is supplied with either high-pressure water from a high-pressure water supply source (high-pressure water pump) or grout material from a grout supply source (grout supply pump). Further, the air supply swivel 16 is supplied with compressed air from a compressed air supply source.

Note that casters 19 for movement are attached to the bottom of the device frame 1.

Although the high-pressure flexible hose 10 is flexible, it has a large diameter (7c+n to 10-odd coo) and rotates during use, making it difficult to handle with bare hands, as shown in FIGS. 9 and 10. Attach multiple tools 2o to the outside of the flexible hose]0.

That is, the tool 20 has a bearing 2 inside the cylindrical body 21.
2 is fixed to the cylindrical body 21, and an arm 23, which is held by the operator by hand, is integrally connected to the outer periphery of the cylindrical body 21 by welding or the like, and the bearing 22 fits loosely into the flexible hose 10 so that the position can be shifted. It has become.

To change the direction of the flexible hose 10 by about 90 degrees, apply a force in the direction of arrow X to the arm 23 of the tool 2o on the front end side, and apply a force in the direction of arrow Y to the tool 2o on the rear end side, as shown in Fig. 9. This can be easily done by The tool 20 is in contact with the flexible hose 7 and 10 through a bearing 22, so that when the flexible hose 10 is rotated at low speed, the tool 20 does not interfere with the low speed rotation, and even when bent 90 degrees, the flexible hose 10 can transmit rotation to the tip member 13.

First, the ground improvement method of the present invention will be explained by taking as an example the case where construction is performed to prevent pipeline subsidence.

Using the excavation device 60 shown in FIGS. 1 to 3, the vertical shaft 31 is rotated left and right with a boring machine, and a vertical hole 61 is drilled in the ground adjacent to the ground part that requires reinforcement as shown in FIG. 11. and excavate. The excavated soil will be pumped up and discharged using a mud pump. Then, after excavating the vertical hole 61 to a depth D for injecting the grout material as shown in FIG. 12, the excavating device 60 is pulled up.

The width of the vertical hole 61 is as narrow as necessary, as shown in the plan view of FIG.

Next, as shown in FIG. 14, an abbreviated guide pipe (for example, a plastic elbow pipe) 70 having an integrated back support plate 71 and bottom support plate 72 is placed in the vertical hole 61. that time,
The high-pressure flexible hose 10 may be inserted in advance on the ground, or the high-pressure flexible hose 10 may be inserted after the abbreviated guide pipe 70 is arranged.

Thereafter, the ground improvement device 8° shown in FIGS. 5 to 7 is placed at an appropriate location and the rear end of the high-pressure flexible hose 10 is connected to the device 8. First, high-pressure water is supplied to the liquid supply swivel 17. A compressed air source is connected to the air supply swivel 16. Then, as shown in Figure 9, tool 2
0, bend the flexible hose 10 and send the abbreviated shape into the pipe 70. In other words, the tip of the flexible hose is fed to the lower part of the pipeline 75 in Fig. 14, which is the ground area to be reinforced, and high-pressure water 8
0 kg/c+n2 or more) through the liquid supply swivel 17 and the small diameter flexible hose 18 from the liquid injection port 11 of the tip member 13, while rotating the flexible hose 10 (that is, the tip member 13) at a low speed (every (about 25 revolutions per minute). At this time, when the water has sufficiently penetrated into the ground, compressed air is injected forward through the air injection port 12 through the internal spaces of the air supply swivel 17, hollow metal pipe shaft 5, and flexible hose 10, to remove the mud inside the ground. The distal end member 13 is advanced in a substantially horizontal direction toward the back of the distal end using an abbreviated guide pipe 70 while mixing water and air bubbles and discharging them to the outside.

After inserting the tip member 13 deep into the ground to be reinforced and discharging the mud, the supply of high-pressure water and compressed air is stopped, and a grout supply source is connected to the liquid supply swivel 17. Here, the grout material is a cement-based rapidly hardening material or the like.

Then, with medium pressure, the liquid jet port 11 of the tip member 13 is
The flexible hose 10 (
That is, the flexible hose 10 is gradually pulled out using the tool 20 while rotating the tip member 13) at a low speed. As a result, the voids in the roadbed after mud has been removed are filled with grout material, mixed with internal gravel, etc., and solidified, thereby making the ground stronger and thereby preventing the pipeline 75 from sinking.

In this case, it is superior to chemical liquid injection using vertical poling in that the ground below the pipeline 75 can be reliably reinforced, and the installation space for the device is also small, and the vertical hole size is such that the guide pipe 70 is arranged in an abbreviated shape. It is superior to chemical injection using horizontal poling in that it requires minimal dimensions.

FIG. 15 shows a case where the ground portion below a reinforced concrete roadbed 85 of a railway laid on an embankment 90 is reinforced. After excavating the vertical hole 61A with the excavating device 60 in the same manner as in FIGS. 11 to 13, the abbreviated guide pipe ? After arranging the OA, the high-pressure flexible hose 10 from the ground improvement device 80 is let out in a substantially horizontal direction from the approximately --shaped guide pipe 70A, and mud is removed by a combination of high-pressure water and air as in the case described above, and then can be filled with grouting material.

In this case, it is superior to chemical injection by vertical poling in that it does not require drilling holes in the reinforced concrete roadbed 85 and does not deteriorate the roadbed, and also allows the device to be installed in a small space. It is superior to chemical injection using horizontal poling in that it requires minimal dimensions.

In addition, when filling the grout material by injection, the injection of compressed air from the air injection port 12 may be appropriately used in combination to increase the mixing and stirring effect when filling the grout inside the ground.

(Effects of the Invention) As explained above, the present invention does not require a small space to place the construction equipment, and moreover, it is possible to reliably inject grout material almost horizontally into the ground area that requires improvement. , can effectively reinforce the ground beneath reinforced concrete roadbeds, pipelines, or other structures.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the drilling equipment according to the present invention, and is a partially sectional front view, FIG. 2 is a side view, FIG. 3 is a plan view, and FIG. IV sectional view, FIG. 5 is a plan view showing the soil improvement device used in the example, FIG. 6 is a front view of the same, FIG. 7 is a side view of the same, and FIG. 1148 is a front view with a part of the tip member in cross section. Figure 9 is a plan view illustrating the cutting process for bending a flexible hose, Figure 10 is a cross-sectional plane view showing a tool for fabricating a flexible hose, and Figures 11 and 12 are a ground improvement method according to the present invention. Fig. 13 is a plan view of the vertical hole; Fig. 14 is a sectional view showing the arrangement of the abbreviated guide pipes and an example of ground improvement; Fig. 15 is a cross-sectional view of the ground improvement; It is a sectional view showing another construction example of improvement. DESCRIPTION OF SYMBOLS 1... Equipment frame, 2... Electric motor, 3... Continuous reduction gear, 4... Bearing, 5... Hollow metal pipe, 6,
8... Sprocket, 7... Chain, 10...
High pressure flexible hose, 11...Liquid injection port, 12
...Air injection port, 13...Tip member, 18...Small diameter flexible hose, 20...Tool, 30...Gear case, 31...Vertical axis, 35.37...Horizontal axis ,
43...Drilling shaft, 50,53...Drilling blade, 52.
...Chain, 60...Drilling equipment, 61.61A...
・Vertical hole, 70.70A...abbreviated guide pipe, 8
0... Ground improvement device.

Claims (4)

[Claims] (1) A vertical hole is excavated in the ground, a substantially L-shaped guide pipe is placed in the vertical hole, and a flexible hose with a liquid injection port provided at the tip is inserted into the substantially L-shaped guide pipe either beforehand or after the vertical hole is placed. The tip side of the flexible hose is held substantially horizontally by the substantially L-shaped guide pipe, and the flexible hose is fed out into the ground while being rotated, and high-pressure water is injected from the liquid injection port into the ground. After discharging the muddy soil, the flexible hose is pulled out from the ground while being rotated while injecting grout material from the liquid injection port. (2) The ground improvement method according to claim 1, wherein an air injection port is provided at the tip of the flexible hose, and air injection from the air injection port is used in combination with the injection of the high-pressure water. (3) An excavation device characterized in that the rotation of the vertical axis is transmitted via a transmission mechanism to an endless band provided with a large number of excavation blades on the outside, and a vertical hole is formed in the ground by the rotation of the endless band. (4) The excavation device according to claim 3, wherein a large number of excavation blades are provided on a shaft body that rotates in conjunction with the endless band.