JP2727153B2 - Ground improvement equipment and construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement apparatus and method for forming a pile made of a hardening agent in the ground to stiffen the ground by injecting a hardening agent into the ground.

[0002]

2. Description of the Related Art Conventionally, a hole is formed in the ground from the ground surface, and a hardening agent such as cement milk is injected and injected from a hardening agent injection rod into the hole, and the hardening agent is rotated while rotating the hardening agent injection rod. A ground improvement method has been developed in which an injection rod is gradually pulled back to form a hardened pile in the ground.

In this type of ground improvement method for destroying the core structure, it is necessary to discharge underground mud (slime) to the surface of the ground in place of the injected hardener liquid. If the mud is not discharged smoothly, the pressure in the ground at the injection injection point will increase, and the surrounding ground surface will rise, adversely affecting nearby structures, and the injection rod and casing (guide pipe) In some cases, it may be impossible to perform the installation due to the occurrence of the mining. The problem of the discharge of the sludge becomes more serious as the depth of the formation pile formed from the ground from the surface becomes deeper. Also, the discharge of mud may hurt the surrounding ground.

Therefore, conventionally, in order to prevent an increase in the internal pressure of the ground at the injection injection point, an injection rod is provided with a mud suction port, and the excess hardener and mud are discharged through the injection rod through the suction port. Attempts have been made to release ground pressure at the injection point by discharging mud from the injection point to the surface.

[0005]

However, in the conventional apparatus for forcibly sucking the sludge through the sludge inlet through the sludge inlet, the sludge is discharged to the sludge suction inlet and the sludge discharge passage in the sludge rod. There is a drawback that a large mass of mud or foreign matter is clogged and clogged easily. In view of the above, an object of the present invention is to provide a ground improvement device and a construction method capable of effectively and smoothly discharging mud to the ground.

[0006]

According to the present invention, there is provided a ground improvement apparatus for achieving the above-mentioned object, wherein a hardening agent is injected into a hole formed in the ground at a high pressure by an injection rod, and the rod is pulled up. In the ground improvement apparatus for forming the formed pile hardened by the hardening agent on the target ground, a cylindrical guide pipe and an inner periphery of the guide pipe having a non-circular cross-section that can be inserted into the guide pipe are provided. An inner injection rod having a hardening agent injection nozzle at the tip end while being inscribed in the surface, a driving device capable of individually rotating and driving the guide tube and the inner injection rod, a sludge suction device, and the guide tube Between the inner peripheral surface of the inner injection rod and the outer peripheral surface of the inner pouring rod and the sludge suction device, and a part of the rotation trajectory of the empty space is closed, whereby the empty space is closed. of Is characterized by having a discharge swivel to intermittently communicated with said waste sludge suction unit and said cavity with the rolling.

Preferably, the inner injection rod is provided with a high-pressure water injection nozzle behind the hardener injection nozzle, and the injection direction of the high-pressure water injection nozzle is directed toward the rear side of the inner injection rod. . Further, the inner injection rod is formed in a shape twisted around the longitudinal axis, whereby the discharge passage of the sludge formed by the space is formed in a spiral shape. A through-hole for sucking out mud may be formed near the tip of the guide tube.

In the ground improvement method according to the present invention for achieving the above-mentioned object, a rod for injecting a hardening agent into a hole formed in the ground while the hardening agent is injected at a high pressure raises the rod. In the ground improvement method of forming the formation pile hardened by the hardening agent on the target ground, an inner injection rod having a non-circular cross section is inscribed and inserted into the cylindrical guide pipe, and the tip of the inner injection rod is inserted. While injecting a curing agent from the tip while rotating the inner injection rod while being exposed from the guide tube,
It is characterized in that the sludge is intermittently sucked from a space formed between the guide tube and the inner injection rod.

[0009]

The tip of the inner injection rod is exposed from the guide tube, and the mud suction device is operated while the guide tube and the inner injection rod are relatively rotated to inject the curing agent. Suction is performed intermittently by the intermittent communication between the empty space and the mud suction device by the discharge swivel. Exercise prevents sticking and clogging in voids. The injected high-pressure water crushes the sucked mud and contributes to a decrease in specific gravity and viscosity. The high-pressure water injected to the rear side proceeds to the vacant space accompanied by wastewater in addition to the above operation. By making the inner injection rod a twisted shape and making the sludge discharge passage spiral, the transfer of the sludge is promoted by the effect of centrifugal force.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an operation rod of a ground improvement device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a distal end portion of the operation rod, FIG.
1 is an overall schematic configuration diagram of this ground improvement device. As shown in FIGS. 1 and 2, in the present ground improvement apparatus, an operation rod 11 which is put into the ground and performs a required operation is composed of a guide pipe 12 and an inner injection rod 13 inserted inside the guide pipe 12. It consists of

The guide tube 12 has a cylindrical shape, and an excavation blade 14 is attached to a peripheral edge of the guide tube 12. The size of the guide tube 12 is appropriately determined depending on the construction conditions, but is, for example, about 165 mm in diameter at a large depth construction of 30 to 40 m. The inner injection rod 13 has a triangular prism shape with a transverse cross section of an equilateral triangle, and its three vertices are sized to be slidably in contact with the inner peripheral surface of the guide tube 12 (FIG. 1).
reference). Therefore, when the inner injection rod 13 is inserted into the guide tube 12, three voids 15 are formed which are partitioned by the inner peripheral surface of the guide tube 12 and the outer wall surface of the inner injection rod 13. These cavities 15 serve as a discharge route of the sludge to be described later.

In the inner injection rod 13, a hardening agent flow path 16 and a high-pressure water flow path 17 are formed concentrically along its longitudinal axis along the outer periphery thereof. At the distal end of the inner injection rod 13, as shown in FIG. 2, an injection nozzle 18 communicating with the curing agent flow path 16 is provided.
An injection nozzle 19 communicating with the high-pressure water flow path 17 is provided slightly behind the injection nozzle 19. Two high-pressure water injection nozzles 19 are provided, and both are arranged at an angular interval of 180 degrees so as to inject in opposite directions. Also, a digging blade 20 is provided at the tip edge of the inner injection rod 13.
Is attached. These guide tube 12 and inner injection rod 13 have a length of 1.5 to
It has a plurality of detachable intermediate pipes (not shown) of about 3.0 m, and the entire length thereof can be appropriately adjusted according to the depth of the formed pile formed by connecting the intermediate pipes. ing.

As shown in FIGS. 3 and 4, the guide tube 12 and the inner injection rod 13 are supported by a driving machine 21 so that required operations are performed. In FIG. 3, reference numeral 22 denotes a machine main body having a built-in drive source, 23 and 24 denote chucks for holding the guide tube 12 and the inner injection rod 13, respectively, and 25 denotes a guide tube 12
Reference numeral 26 denotes a guide tube spindle for rotationally driving the rotary disk 25, reference numeral 27 denotes a rotary disk for the inner injection rod 13, and reference numeral 28 denotes an inner injection rod spindle for rotationally driving the rotary disk 27. And the inner injection rod 13 are independently driven to rotate about a longitudinal axis and driven forward and backward along the longitudinal axis. Here, as described above, each of the guide tube 12 and the inner injection rod 13 has a separate rotation driving device, and is preferably driven to rotate in a direction opposite to each other at an appropriate rotation speed.

Further, a high-pressure swivel 29 is connected to the upper end of the inner injection rod 13, from which a hardener and high-pressure water are respectively supplied to a hardener flow path 16 and a high-pressure water flow path 17 in the inner injection rod 13. Supplied. In FIG. 4, reference numerals 30 and 31 denote a curing agent supply device and a high pressure water supply device connected to the high pressure swivel 29, respectively.
On the other hand, a discharge swivel 32 is connected to the upper end of the guide tube 12. The swivel 32 communicates the space 15 formed between the above-described guide tube 12 and the inner injection rod 13 with the sludge suction device 33 shown in FIG. A well-known suction pump such as a vacuum pump (vacuum) or a squeeze pump can be used as the sludge suction device 33.

FIG. 5 is a cross-sectional view of the conduction port portion of the discharge swivel 32. The discharge swivel 32 is located in the empty space 1 described above.
5 has a fan-shaped conduction port 34 that covers the rotation locus. In the present embodiment, as shown in FIG. 5, this fan shape is one-third of the rotation locus ring (an angle range of 120 degrees). Only when the space 15 formed between the guide tube 12 and the inner injection rod 13 faces this conduction port 34, the space 15 and the mud suction device 33 can communicate with each other. ing. In this embodiment, the discharge swivel 32 is opened by one third of the entire circumference, but the degree of this opening is appropriately selected depending on construction conditions such as the properties of the ground.

Next, a method of forming a formed pile by the ground improvement apparatus having such a configuration will be described. FIG. 6 is an explanatory view when forming a formation pile by this ground improvement device. 1) As shown in FIG. 6, first, while rotating the guide tube 12 having a circular cross section, the guide tube 12 is advanced underground to perform pre-drilling (FIG. 6A). 2) Next, the inner injection rod 13 is inserted into the guide tube 12.
Then, the guide tube 12 is pulled up a little (for example, 1.00 m to 2.00 m), and the injection nozzles 18 and 19 provided at the distal end of the inner injection rod 13 are inserted. The end of the guide tube 12 is exposed to the outside (FIG. 3C). 3) After that, the curing agent supply device 30 and the high pressure water supply device 31
To start the injection of the curing agent and high-pressure water,
While rotating the guide tube 12 and the inner injection rod 13 in directions opposite to each other, the two tubes 12, 13 are simultaneously pulled up (FIG. 4D). At the same time, the sludge suction device 33
Is operated to suck the sludge. For example, the guide tube 12 is 1 rotation / min, and the inner injection rod 13 is 6 rotations / m.
It is driven to rotate at a speed of in. 4) In this way, the two pipes 12, 13 are pulled up, and when the required height of the formation pile 35 is achieved, the inner injection rod 13 and the guide pipe 12 are cut off in this order to complete the construction (FIG. e)). Although not shown, both pipes 1
In the insertion step and the lifting step of steps 2 and 13, the connection and disconnection of the intermediate pipe are performed sequentially as in a normal boring step.

While the above-mentioned curing agent and high-pressure water are being sprayed, both pipes 1
In the step of pulling up the second and the 13th, the sludge displaced by the hardening agent contains the guide tube 12 and the inner injection rod
Is sucked from the space 15 formed between here,
The discharge swivel 32 for communicating the empty space 15 with the sludge suction device 33 intermittently connects the empty space 15 rotating with the rotation of the inner injection rod 13 to the sludge suction device 33. Accordingly, the suction is performed intermittently with respect to each of the cavities 15, and the sludge being sucked causes a continuous vertical movement. The movement of the sludge in the suction process prevents the adhesion and clogging in the empty space 15.

Further, the high-pressure water injected from the high-pressure water injection nozzle 19 crushes the sludge mass and lowers the specific gravity and viscosity of the sludge, and is combined with the above-mentioned intermittent suction of the sludge. Contributes to smooth discharge. In addition, it is effective to mix air or chemicals in water or to spray air instead of water in order to crush sludge and lower the specific gravity and viscosity. Also,
In the above-described embodiment, the inner injection rod 13 has a triangular cross section.
Is not limited to this, and a closed space 15 is formed between the inner peripheral surface of the guide tube 12 and the outer peripheral surface of the inner injection rod 13 in contact with the inner peripheral surface of the guide tube 12. What is necessary is just a thing of a non-circular cross section. 7 to 9 are schematic cross-sectional views of another embodiment of the inner injection rod according to the present invention.

FIG. 7 shows an example of a square section, and FIG. 8 shows an example of an elliptical section. Also, the one shown in FIG. 9 is formed with a ridge 36 whose tip is in sliding contact with the inner peripheral surface of the guide tube 12 on the outer peripheral portion of the inner injection rod 13 having a circular cross section, and the space 15 is formed between the ridges 36. It is made to be done. Further, in the above embodiment, the inner injection rod 13
Has a triangular prism shape, so that the discharge flow path of the sludge formed by the space 15 formed between the guide tube 12 and the inner injection rod 13 has a straight shape along the longitudinal axis direction of the inner injection rod 13. However, in the present invention, it is possible to improve the discharge efficiency by spirally forming the sludge discharge passage. That is, by making the inner injection rod 13 twisted around its longitudinal axis, the sludge discharge flow path formed by the cavity 15 is formed in a spiral shape, and the twist direction of the spiral and the rotation of the inner injection rod 13 are changed. By considering the direction, it is possible to promote the transfer of the sludge by the effect of the centrifugal force. In this case, the inner injection rod 13 having a non-circular cross section is not limited to a triangular cross section, and a twisted shape can be provided.

FIG. 10 is a cross-sectional view of an operation rod of a ground improvement apparatus according to another embodiment of the present invention. In the above-described embodiment, the wastewater is crushed by injecting high-pressure water or air to reduce its specific gravity and viscosity. However, the embodiment of FIG. It is intended to promote. FIG.
As shown in FIG. 7, in this embodiment, a projection 37 is formed on each wall surface having a triangular cross section, and a high-pressure water injection nozzle 19 is provided there. This injection nozzle 19 is used for the inner injection rod 1.
The direction of the injection is set so that the high-pressure water is injected toward the base end along the longitudinal axis of No. 3.

Therefore, according to such a configuration, the high-pressure water injected from the injection nozzle 19 is directly injected toward the space 15, and in addition to the above-described crushing of the sludge, the specific gravity and the effect of lowering the viscosity, the injection is performed. The force directly contributes to the transfer of the sludge, and a smoother sludge discharge can be achieved.
On the other hand, although not shown in the above embodiment, the guide tube 1
A through hole is formed in the wall near the end of the guide tube 2 and the guide tube 12 is formed.
May be sucked and discharged into the guide tube 12 from the through hole. In this case, it is preferable to provide a check valve that allows inflow from the outside but prevents outflow so that the sludge does not leak from the through hole to the outside of the guide tube 12.

Further, the inner injection rod of the present invention is not limited to the above-described double tube structure. Conventionally, there are known hardener injection rods having various structures in this type of ground improvement apparatus, and the present invention can be applied thereto. For example, the hardener injection nozzle has a double-pipe structure nozzle, injects hardener from the inner nozzle and high-pressure air from the outer nozzle, and extends the reach by surrounding the hardener with high-pressure air. , Similarly, high-pressure water surrounded by air and jetted, or any combination thereof can be used.

[0023]

According to the present invention, as described above in detail with reference to the embodiments, the discharge passage for the sludge is formed in the gap between the guide tube and the inner injection rod. Since the wastewater is intermittently sucked through the passage, the adhesion and clogging of the wastewater to the flow path can be effectively prevented, and the smooth discharge can be performed without adversely affecting the surrounding ground.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an operation rod of a ground improvement device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the operation rod of FIG.

FIG. 3 is a side view of a main part of the ground improvement device of FIG. 1;

FIG. 4 is an overall schematic configuration diagram of the ground improvement device of FIG. 1;

FIG. 5 is a cross-sectional view of a conduction port portion of a discharge swivel of the soil improvement device of FIG.

FIG. 6 is an explanatory view when forming a formation pile by the ground improvement device of FIG. 1;

FIG. 7 is a schematic cross-sectional view of another embodiment of the inner injection rod according to the present invention.

FIG. 8 is a schematic cross-sectional view of another embodiment of the inner injection rod according to the present invention.

FIG. 9 is a schematic cross-sectional view of another embodiment of the inner injection rod according to the present invention.

FIG. 10 is a cross-sectional view of an operation rod of a ground improvement device according to another embodiment of the present invention.

[Description of Signs] 11 Operation rod 12 Guide tube 13 Inner injection rod 15 Void 16 Flow path for hardener 17 High pressure water flow path 18, 19 Injection nozzle 21 Drive machine 22 Machine body 23, 24 Chuck 25, 27 Turntable 26 Guide Pipe Spindle 28 Inner Injection Rod Spindle 29 High Pressure Swivel 30 Hardener Supply Device 31 High Pressure Water Supply Device 32 Discharge Swivel 33 Drainage Suction Device 34 Conduction Port 35 Creation Pile

Claims (10)

(57) [Claims] 1. A ground improvement apparatus for forming a formation pile having hardened hardener on a target ground by pulling up a hardener by injecting a hardener at a high pressure by an injection rod into a hole formed in the ground. An inner injection rod having a non-circular cross-section, being inscribed in the inner peripheral surface of the guide tube, and having a hardener injection nozzle at a distal end portion thereof, which can be inserted into the guide tube, A driving device capable of individually rotating and driving the guide tube and the inner injection rod; a sludge suction device; a space surrounded by an inner peripheral surface of the guide tube and an outer peripheral surface of the inner injection rod; While being interposed between the mud suction device and a part of the rotation trajectory of the cavity is closed, thereby intermittently communicating the cavity with the mud suction device with the rotation of the cavity. Sui for discharge Soil improvement apparatus characterized by having Le and, a. 2. The ground improvement apparatus according to claim 1, wherein the inner injection rod has a high-pressure water injection nozzle behind the hardener injection nozzle. 3. The injection direction of the high-pressure water injection nozzle is directed rearward of the inner injection rod.
The ground improvement device as described. 4. The ground improvement apparatus according to claim 1, wherein the inner injection rod has a polygonal cross section. 5. The ground improvement device according to claim 1, wherein the inner injection rod has an elliptical cross section. 6. The ground improvement apparatus according to claim 1, wherein the inner injection rod is twisted around a longitudinal axis, whereby a discharge passage of the sludge formed by the space is spiral. 7. The ground improvement device according to claim 1, wherein a through-hole for sucking out mud is formed near the distal end of the guide tube. 8. A ground improvement in which a hardening agent hardened formation pile is formed on a target ground by pulling up the rod while injecting the hardening agent at a high pressure into a hole formed in the ground by a rod for injecting the hardening agent. In the construction method, an inner injection rod having a non-circular cross section is inserted into a cylindrical guide tube in an inscribed manner, the tip of the inner injection rod is exposed from the guide tube, and the tip is rotated while rotating the inner injection rod. A ground improvement method, wherein the mud is intermittently sucked from a space formed between the guide tube and the inner injection rod while a curing agent is injected from the portion. 9. The ground improvement method according to claim 8, wherein high-pressure water is injected from the inner injection rod from a rear side of the injection position of the hardener in parallel with the injection of the hardener. 10. The ground improvement method according to claim 9, wherein the high-pressure water injection is performed toward the space.