JPH06185044A - Method and device for improving ground - Google Patents

Abstract

PURPOSE:To improve the ground by impregnating the inside of a poor subsoil with a curing material, mixing the curing material with soil and sand and curing the curing material. CONSTITUTION:Inner and outer double pipes 1, 2 are inserted horizontally toward the ground to be improved A from a shaft 3 installed at the peripheral proper place of said ground A, a curing material is injected into the ground from an injection nozzle 4 mounted at the front end of the inner pipe 1 projected from the front end of the outer pipe 2, and excess slime in the ground generated by mixing the curing material with soil and sand and agitating the mixture is removed through the inside of said inner pipe 1 from an intake mouth 11 formed to the inner pipe 1. The internal pressure of the ground is detected by a pressure sensor 8 set up at the front end section of the internal pipe 1, and the outer pipe 2 is rotated longitudinally or in the circumferential direction in response to the detecting value, thus changing the degree of overlapping of the opening section 21 of the front end of the outer pipe 2 and the intake mouth 11, then adjusting the degree of opening of the intake mouth 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the ground by mixing and hardening a hard ground material with a hardening material, and an apparatus for carrying out this method.

[0002]

2. Description of the Related Art In order to improve soft ground, a method is known in which a liquid hardening material such as cement is injected into the ground, mixed with earth and sand, stirred and then hardened. As a method for improving the ground in a desired range by using the method, as shown in FIG. 9, a pipe P having an injection nozzle n at the tip is inserted from the ground surface to a desired depth, and the pipe is rotated around the pipe axis. While doing so, the hardening material is sprayed from the nozzle n at a high pressure to slime the ground.

At this time, excess slime is generated in the ground, the internal pressure of the ground increases, and as a result, the ground rises. Therefore, the excess slime must be removed. On the other hand, as shown in FIG. 10, when the compressed air is injected along with the high-pressure injection of the hardening material in order to inject the hardening material into a wide area of the ground, the air also needs to be removed.

As a method of removing such excess slime S and air, conventionally, a method of naturally pushing up toward the ground side by utilizing the injection pressure of a hardening material or the like, or a pipe P
A method is adopted in which the hardening material is jetted from the lower end of the pipe together with the jet of air, and the floating force of the air, that is, the air lift, is transmitted along the gap between the outer peripheral surface of the pipe P and the ground to be actively removed. .

[0005]

However, the above method cannot be applied to a method for improving shallow ground by inserting the pipe P in the horizontal direction parallel to the ground surface. What would happen is, even if you try to remove excess slime using the air lift while inserting the tube horizontally parallel to the ground surface and spraying the hardening material into the ground from the nozzle provided in the tube. The reason is that slime cannot be removed because there is no clearance for discharge that communicates with the ground surface side.

Therefore, as described above, it is possible to use the internal pressure of the ground alone to remove the excess slime while flowing it into the pipe body. In this case, the pipe body is gradually stirred while mixing and stirring the hardening material. When pulled out, the tube becomes shorter,
The resistance in the pipe becomes small, the excess slime is easily discharged, and the pressure in the ground improvement section drops abnormally. In addition, the pressure also drops when the pipes are replenished or separated.
Furthermore, the mouth of the excess slime provided in the pipe body may be blocked by a lump of earth and sand or the like. As a result, there is a problem that uplift or subsidence of the ground occurs, which adversely affects the ground surface and buildings around the ground improvement area. An object of the present invention is to provide a ground improvement method capable of solving such a problem and an apparatus used for implementing the method.

[0007]

In order to achieve the above object, the ground improvement method of the present invention is designed so that the inner and outer double pipes are inserted into the ground to be improved and the tip of the inner pipe is projected from the outer pipe. In this state, the hardened material supplied through the inner pipe is sprayed from the tip nozzle into the ground to make the ground slime and the excess slime is removed through the inner pipe from the dowel provided at the proper position of the tip of the inner pipe. Adjusting the opening degree of the dowel by changing the polymerization degree between the tip of the outer tube and the dough by moving the outer tube back and forth or rotating according to the pressure while measuring the pressure of the ground improvement part. It is characterized by.

An apparatus for carrying out the above method is
An inner pipe equipped with a nozzle for injecting a hardening material at the tip, a mouth for receiving excess slime, and a pressure sensor for detecting the internal pressure of the ground, and the inner pipe is rotatably and rotatably fitted to the inner pipe. It comprises an outer tube whose part is superposed on the mouth of the inner tube, and a drive device for moving the outer tube back and forth or rotating according to the detection value of the pressure sensor.

[0009]

After the inner and outer pipes are inserted into the ground, a liquid hardening material such as cement is sprayed into the ground from the tip nozzle of the inner pipe protruding from the outer pipe, and is mixed with earth and sand by stirring. At this time, if the hardening material is injected while air is jetted from around the nozzle, the hardening energy is agitated and mixed over a wide range of the ground without the injection energy of the hardening material being consumed by the surrounding earth and sand. It can be made slime.
Further, the surplus slime flows into the inner pipe through the dowel provided at the tip of the inner pipe and is discharged to the outside.

On the other hand, the pressure sensor provided at the tip of the inner pipe detects the pressure of the ground improvement portion, and the ground value is preset according to the detected value and the ground condition or the load condition of the structure on the ground. When the detected value is higher than the reference value by comparing with the reference value of the internal pressure, the outer tube is moved back and forth with respect to the inner tube or is rotated by an appropriate angle in the circumferential direction so that the inner end of the outer tube is not Increase the degree of polymerization with the mouth of the pipe, that is, increase the opening degree of the mouth, to increase the amount of excess slime removed, or move the outer pipe back and forth or rotate to remove the lump of earth and sand that blocked the mouth. To do. When the detected value is lower than the reference value, the opening degree of the drinking cup is decreased to reduce the slime removal amount. In this way, the excess slime removal amount is controlled according to the pressure of the ground improvement portion while measuring the pressure of the ground improvement portion, thereby improving the ground to a predetermined strength while preventing the ground from rising or sinking.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows a simplified diagram of the whole ground improvement device, and 1 and 2 are inner and outer double pipes inserted horizontally from the shaft 3 into the ground to be improved in parallel with the ground surface, The outer tube 2 is fitted in the inner tube 1 so as to be movable back and forth and freely rotatable in the circumferential direction, and the tip of the inner tube 1 is projected from the tip of the outer tube 2 when the ground is improved. .

The tip of the inner tube 1 protruding from the outer tube 2 is provided with a hardening material injection nozzle 4 opening downward, and an air injection nozzle 5 is provided around this nozzle 4 as a center. These nozzles 4 and 5 are connected to a hardening material supply pipe 6 and a compressed air supply pipe 7 which are arranged in the inner pipe 1, respectively.
It is in communication. Further, these supply pipes 6 and 7 are connected from a rear end of the inner pipe 1 through a shaft 3 to a hardening material supply source and a compressed air supply source (not shown) arranged at appropriate positions in the shaft 3 or on the ground, It is in communication.

Numeral 8 is a pressure sensor for detecting the pressure of the ground improvement portion, which is arranged at a proper position on the tip of the inner pipe 1 near the tips from the nozzles 4 and 5, and a detection cable 9 connected to the sensor 8. Is connected through the inner pipe 1 to a pressure indicator 10 arranged at a proper position on the vertical shaft 3 or on the ground.
The pressure in the ground detected by is displayed on the pressure indicator 10.

Reference numeral 11 denotes a dowel opening provided on the lower surface side of the tip end portion of the inner pipe 1 near the base end portions from the nozzles 4 and 5, and a short pipe portion 11a at the tip end portion of the slime discharge pipe 12 arranged in the inner pipe 1. The slime discharge pipe 12 has its open end communicating with or facing the slime storage tank 13 installed in the vertical shaft 3 from the rear end of the inner pipe 1. Further, the slime storage tank 13 has a bottom portion thereof with a sludge pipe 16 equipped with a sludge flow meter 14 and a pump 15.
The slime pipe 16 communicates with the above to feed the slime to the above-mentioned slime treatment section (not shown).

Reference numeral 17 is a jet water injection pipe with its nozzle portion facing the center of the tip of the slime discharge pipe 11, and a jet water supply facility (not shown) disposed on the ground through the inner pipe 1.
Connected to. Reference numeral 18 is a control device composed of a computer connected through the pressure indicator 10, and the control device 18 is set in advance with a reference value of the optimum ground pressure depending on the ground condition to be improved and the load condition of the structure or the like. The reference value is compared with the detected pressure value of the ground improvement portion by the pressure sensor 8, and the opening degree of the drinking cup 11 is adjusted and controlled according to the difference.

As a means for adjusting the opening degree of this drinking cup 11,
As shown in FIG. 3, the outer tube 2 is moved in the longitudinal direction so as to adjust the degree of polymerization between its tip and the mouthpiece 11, or as shown in FIG. A structure configured to change the opening degree of the dowel 11 by forming an opening 21 formed of a circular hole having a diameter larger than that of the dowel 11 and adjusting the degree of polymerization of the opening 21 and the dowel 11. As shown in FIG. 5, a U-shaped cutout recess having a length longer than the diameter of the mouthpiece 11 and a width substantially equal to the diameter of the mouthpiece 11 is formed from the tip of the outer tube 2.

Further, in order to adjust the degree of superposition of the opening 21 and the mouthpiece 11, the outer tube 2 is constructed so as to be movable back and forth or freely rotatable in the circumferential direction. As the outer tube driving device, a known boring machine 19 as shown in FIG. 6 can be adopted. That is, the boring machine 19 has a mechanism that allows the inner and outer pipes 1 and 2 to be press-fitted into and retracted from the ground A in a double pipe structure, and the inner and outer pipes 1 and 2.
Each of them has a mechanism for independently rotating in the circumferential direction, and a mechanism for independently moving in the length direction, the drive mechanism of which is electrically connected to the control device 18 and the internal pressure of the ground. It operates according to the detected value of
It controls the opening degree of.

Reference numeral 20 is a quick-connect material supply pipe arranged in the pipe body 1,
The tip nozzle 22 faces downward from the lower end of the tip of the inner tube 1. The quick-linking material supply pipe 20 is connected to a quick-linking material supply source (not shown) installed at a proper position on the vertical shaft or on the ground, like the hardening material supply tube 6 and the compressed air supply tube 7.

In order to improve the ground A, such as directly under a building, by using the ground improvement apparatus configured as described above, first, a vertical shaft 3 is excavated at an appropriate position around the ground, and the vertical shaft 3 is formed in the vertical shaft 3 as shown in FIG.
As shown in FIG. 5, a boring machine 19 is installed, and the outer pipe 2a of a fixed length is press-fitted toward the ground A to be improved by the boring machine 19 in parallel with the ground surface. At this time, the outer tube
The outer pipe 2a is pressed into the ground by discharging the excavated earth and sand to the shaft side through the outer pipe 2a while excavating the earth and sand on the tip side of the outer pipe 2a with a punching tool such as an auger screw inserted in 2a. . After press-fitting one split outer tube 2a, the outer tube
Connect the next split outer tube 2a to 2a, press fit into the ground in the same manner as above, and repeat this work to embed the long outer tube 2 connected in series up to a predetermined depth (length) in the ground. To do.

Then, as shown in FIG. 7, the inner pipe 1 is inserted into the outer pipe 2 by using a boring machine 19 in the long outer pipe 2. At this time, like the outer pipe 2, a series of long inner pipes 1 is connected to the outer pipe 2 while sequentially adding the fixed length divided inner pipes 1a.
Insert it inside. The various supply pipes 6, 7, 17, 20 to be arranged in the inner pipe 1 at the time of adding the fixed length inner pipe 1a, the slime discharge pipe 12, the detection cable 9 and the like are connected to each other.

In this way, the inner tube 1 is inserted into the outer tube 2 and the tip of the inner tube 1 is projected from the tip of the outer tube 2 until its mouth 11 reaches a position facing the opening 21 of the outer tube 2. Let In this state, the inner and outer tubes 1 and 2 are reciprocally rotated integrally in the circumferential direction by a driving device over a desired angle range, and a hardening cement injection nozzle 4 opened downwardly through a hardening material supply tube 6 to remove liquid cement or the like. The hardening material is sprayed and poured into the ground to stir and mix with the earth and sand to make the earth and sand slime. At this time, a quick-linking material injection nozzle that opens downward at the tip of the inner pipe 1.
The quick-setting material supplied from 22 through the supply pipe 20 is also injected and injected into the ground A at the same time to accelerate the hardening of the hardened material.

Further, when compressed air is supplied to the air injection nozzle 5 provided around the hardening material injection nozzle 4 through the supply pipe 7 to inject the air from the nozzle 5, the jet pressure of the compressed air into the ground A Since a void is formed in the void, and the curing material is injected from the injection nozzle 5 into the void, the energy of the curing material is not consumed by the sand and the curing material is spread over a wide range. Can be injected.

In this way, while the inner and outer pipes 1 and 2 are integrally reciprocally rotated in the circumferential direction, the hardening material is jetted and injected over a predetermined range of the ground A below the tip of the inner pipe 1 to mix with the earth and sand. The soil is made into a slime by stirring, and the inner and outer pipes 1 and 2 are gradually retracted to the vertical shaft side to inject the hardening material into the ground below along the length direction thereof, as shown in FIG. To improve the ground Aa over a predetermined depth and a desired range. In addition, the inner and outer pipes 1 and 2 drawn out to the vertical shaft 3 side
When the length reaches the appropriate length, the divided pipes 1a and 2a are sequentially removed. At this time, since the above-mentioned pipes and cables in the inner pipe 1 are once separated, the tip portion of the inner pipe 1 is retracted into the outer pipe 2 to close the drinking cup 11 and eliminate excess slime described later. At the same time as stopping, the ground pressure is maintained at a predetermined value.

As described above, the hardening material is sprayed and mixed on the ground Aa to improve the ground A. However, by spraying and mixing a large amount of the hardening material, excess slime is generated and air is blown into the soil. It will be in the existing state. This excess slime and air is discharged from the mouth 11 of the inner pipe 1 to the discharge pipe in the inner pipe 1.
It is forced into the rear end side of the inner pipe 1 by the jet water from the jet jet pipe 16 opened at the tip of the discharge pipe 12 and is discharged to the storage tank 13 in the vertical shaft 3 smoothly. However, since the mouthpiece 11 is formed in advance in a size that allows the amount of slime that exceeds the amount of excess slime to pass,
Until that time, the ground pressure decreases and ground subsidence occurs, and when the dough 11 is clogged with gravel, etc., the slime cannot be removed, the ground pressure rises, and fluctuations such as ground uplift occur. When it occurs, it will adversely affect the structures above and surrounding it, the surrounding ground, etc.

Therefore, the pressure sensor 8 provided at the tip of the inner pipe 1 always detects the pressure in the ground Aa, and controls the amount of excess slime or air removed according to the detected value. Is what you are doing. That is, the ground pressure detected by the pressure sensor 8 is displayed on the pressure indicator 10 from the detection cable 9, and the measured value is compared with the preset reference value of the predetermined ground pressure by the controller 18. Depending on the difference between the detected value and the reference value, the driving device moves the outer tube 2 in the front-rear direction with respect to the inner tube 1 or rotates the outer tube 2 by a predetermined angle in the circumferential direction, thereby forming a drinking mouth.
The degree of polymerization between the opening 11 and the opening 21, that is, the opening degree of the dovetail 11 is adjusted to be large or small, and the amount of excess slime or air flowing in from the dovetail 11 is controlled according to the ground pressure. Note that such control may be performed by an operator reading the display value of the pressure indicator 10 and manually driving the outer tube 2 according to the value, without being automatically controlled by the control device 18.

As described above, when the ground pressure is higher than the reference value, the opening degree of the drinking cup 11 is increased to increase the amount of slime removed, and when the ground pressure is lower, the opening degree of the drinking cup 11 is reduced to remove slime. By reducing the amount, the ground pressure is controlled so that it always becomes the reference value.
If the gravel or the like existing in the soil is clogged, the opening 21 of the outer tube 2 is moved in the direction in which the throat 11 is completely closed to shear the gravel and allow the gravel to flow into the throat 11. is there.

[0027]

As described above, according to the present invention, the inner and outer double pipes are inserted into the ground to be improved, and the hardening is supplied through the inner pipe with the tip of the inner pipe protruding from the outer pipe. By spraying the material from the tip nozzle into the ground, the ground is slimmed and excess slime is removed from the dowel provided at the proper position at the tip of the inner pipe through the inner pipe. While measuring the pressure, the outer pipe is moved back and forth or rotated according to the pressure to adjust by changing the degree of polymerization of the outer pipe tip opening portion and the dovetail, so that the surplus in the ground When the amount of slime increases and the pressure of the ground improvement portion rises, the amount of slime that flows into the pipe can be increased to lower the pressure of the improvement portion to a predetermined value. The pressure in the modified part is lower than the specified value. And when those can increase the pressure of the improved part by reducing the elimination of slime to a predetermined value. Furthermore, when clogging occurs in the dough due to gravel, etc., the outer tube can be moved relative to the inner tube to shear and remove gravel, etc. at its tip,
The slime can be reliably removed from the drinking cup.

Therefore, the pressure of the ground improvement portion can be constantly controlled to a predetermined pressure during the ground improvement by injecting and mixing the hardening material to the soil, and the ground can be efficiently improved while preventing the ground from rising or sinking. In addition, even if the ground is directly below the building, by inserting the pipe body horizontally from the ground around the building, smooth improvement is possible without affecting the structure. It will be.

[Brief description of drawings]

FIG. 1 is a simplified vertical cross-sectional side view of the entire device for ground improvement.

FIG. 2 is a cross sectional view thereof,

FIG. 3 is a front view showing an embodiment of the opening degree adjusting portion of the drinking cup,

FIG. 4 is a partially cutaway front view showing another embodiment of the present invention,

FIG. 5 is a partially cutaway front view showing still another embodiment of the present invention,

FIG. 6 is a process diagram of press-fitting an outer pipe into the ground to be improved,

FIG. 7 is a simplified vertical sectional side view showing a state in which an inner pipe is inserted into the outer pipe.

FIG. 8 is a simplified vertical sectional side view showing a state where ground improvement is being performed.

FIG. 9 is a simplified vertical sectional view showing a conventional ground improvement method.

FIG. 10 is a simplified vertical sectional view showing another conventional ground improvement method.

[Explanation of symbols]

 1 Inner pipe 2 Outer pipe 3 Vertical shaft 4 Curing material injection nozzle 8 Pressure sensor 11 Dowel 12 Slime discharge pipe 18 Control device 19 Boring machine 21 Opening part

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Susumu Murakami 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka City Okumura-gumi Co., Ltd. (72) Inventor Tetsuya Hironaka 2-2-2, Matsuzaki-cho, Abeno-ku, Osaka Incorporation company Okumura Gumi (72) Inventor Hiroshi Wada 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka City Incorporation company Okumura Gumi (72) Inventor Shiro Nakajima 3-1-5 Satakedai Suita-shi, Osaka

Claims (4)

[Claims] 1. A hardening material supplied through an inner pipe is injected from the tip nozzle into the ground by inserting the inner and outer double pipes into the ground to be improved and projecting the tip of the inner pipe from the outer pipe. By making the ground slime by doing so, excess slime is eliminated through the inner pipe from the dowel provided at the tip of the inner pipe, and the opening degree of this dough is measured according to the pressure while measuring the internal pressure of the slimmed soil. A method for improving the ground, characterized in that the outer pipe is moved back and forth or rotated to change the degree of polymerization between the outer pipe tip opening and the mouthpiece. 2. An inner pipe having a nozzle for injecting a hardening material at its tip, a mouth for receiving surplus slime, and a pressure sensor for detecting the internal pressure of the ground, and an inner pipe rotatably and rotatably attached to the inner pipe. A ground improvement device comprising an outer pipe fitted and having a tip portion superposed on a mouth of the inner pipe, and a drive device for moving the outer pipe back and forth or rotating according to a detection value of the pressure sensor. . 3. The ground improvement device according to claim 2, wherein a hole is formed in a peripheral wall of a front end portion of the outer pipe so as to correspond to a mouth of the inner pipe. 4. The ground improvement device according to claim 2, wherein a cutout recessed in the lengthwise direction from the tip of the outer tube is formed at the tip of the outer tube corresponding to the mouth of the inner tube. .