JP5186149B2 - Ground improvement monitor, ground improvement device, and ground improvement method using the ground improvement monitor - Google Patents

Description

  The present invention relates to a ground improvement monitor, a ground improvement device, and a ground improvement method using the ground improvement monitor used for ground improvement work to which a chemical solution injection method, a high-pressure injection method, and the like are applied.

  The drilling method in the high-pressure jet agitation method is divided into a method of directly drilling with a monitor connected to a rod, and a method of drilling with a separate casing and standing a rod and a monitor in the casing. The direct drilling method is quicker due to the absence of a separate drilling process with the casing, but the monitor requires a mechanism to switch the path from drilling to injection, but the improved material has a large discharge rate and ultra-high pressure. In order to inject at a high speed, there is a problem in the reliability of the path switching mechanism, and it has not been used for the construction of an improved body with a large diameter.

  On the other hand, the casing drilling method is not reliable because it does not have a path switching mechanism in the monitor, but it is highly reliable for injection at high discharge rates and ultra-high pressures. Therefore, a process for pulling out the casing is necessary.

  In addition, a large amount of slime corresponding to the discharge amount is generated and discharged by injection with a large discharge amount and ultra high pressure, but this large amount of slime is not completely discharged, and the finished product of the improved body in construction.・ There are cases in which quality is adversely affected, and useful methods for promoting slime discharge have been demanded.

  In the direct drilling type monitor, there is one passage having both a drilling water supply passage for supplying drilling water and an improvement material supply passage for supplying improvement material. The drilling outlet and injection port are provided in the monitor connected to the rod, and both lead to one of the passages. After the drilling is completed, the steel balls are put into the passage and the improved material is pumped. Is transported to the ball receiving base provided between the discharge port for drilling holes and the injection port by the pressure of the improving material, and is fitted into the ball receiving base. As a result, the path to the discharge port for drilling is blocked downstream from the injection port, and only the path to the injection port remains, so that the improved material is injected only from the injection port (see Patent Document 1).

Japanese Patent Laid-Open No. 51-150819 (FIG. 1)

  The ball pedestal is formed so as to face the flow of water and improvement material from the front in order to fit with the steel ball, so foreign matter such as earth and sand remains on the ball pedestal, and the ball pedestal Both steel balls and steel balls are slightly eroded and deformed each time the improvement material is injected, so that the steel balls and the ball seats do not completely adhere to each other, and a gap through which the improvement material passes is formed.

  And when this clearance gap is large, since the path | route to the discharge port for hole drilling is not interrupted | blocked completely, the discharge pressure of an improved material cannot be raised to a desired pressure. In addition, when the gap is fine, the discharge pressure of the improving material can be increased to a desired pressure once. However, after a while, the fine gap is rapidly eroded by the improving material and the desired pressure cannot be obtained. As a result, in the case of a direct drilling type monitor, it is impossible to create an improved body with a large diameter.

  In addition, every time the ground improvement work at one place is completed, the rod must be disassembled each time to collect the steel balls and clean the monitor, which increases the work time.

  An object of the present invention is to provide a ground improvement monitor capable of forming a large-diameter improved body while reducing the working time while being a direct drilling type monitor. .

The invention according to claim 1 is a ground improvement monitor that is used for drilling the ground in the ground improvement work and injecting or injecting the improvement material into the ground, and is connected to a rod, and supplies water. A hole for discharging a hole for discharging water to the ground is formed on a wall surface that has a supply passage and forms the water supply channel, and a blocking means that reversibly deforms and closes and blocks the wall surface It is provided in the said wall surface in the upstream of the discharge outlet for use.
Here, the upstream side refers to the side connected to a device to which water is supplied in the water supply passage.
When the shut-off means is operated, the shut-off means that is in close contact with the wall surface forming the water supply passage and deforms following the unevenness is provided on the upstream side of the discharge port for drilling. Even if a foreign object intervenes between the blocking means and the wall surface, the path to the discharge port for drilling is completely blocked.
In addition, since the blocking means operates reversibly, the work of loading and collecting the steel balls as in Patent Document 1 is not necessary. Therefore, for example, if the construction of the improved body is completed at one construction location and then the operation of the shut-off means is stopped and the state before the operation is restored, the ground improvement monitor and rod will be transferred to the next construction location as they are. Is done.
A water lift discharge port for discharging the water supplied to the water supply passage to the ground is provided upstream of the blocking means of the wall surface forming the water supply passage.
Since the water lift discharge port is provided upstream of the blocking means, the path of the water supply passage can be switched by operating the blocking means. In the case of the high-pressure injection method, water is generally used only during drilling and not during high-pressure injection, but when the path is switched, this water is used to direct water upward from the discharge port for water lift. Can be sprayed to promote the discharge of slime.
A check valve for preventing the material from entering the water supply passage from the hole discharge port is attached to the hole discharge port to prevent the material from entering the water supply passage from the water lift discharge port. A blocking differential pressure valve is attached to the water lift discharge port, and the operating pressure of the check valve is lower than the operating pressure of the differential pressure valve.
Here, being attached to the discharge port for drilling and being attached to the discharge port for waterlift is, for example, an aspect that is fitted to the discharge port or an aspect that is fixed to the ground improvement monitor while covering the discharge port from the outside. In other words, it is only necessary to discharge from the water supply passage to the outside at a desired pressure or higher and to prevent water or an improved material from entering the water supply passage.
Since the operating pressure of the check valve is lower than the operating pressure of the differential pressure valve, only the check valve operates at a predetermined pressure at the time of drilling, and water is discharged only from the discharge port for drilling. Since it is not necessary to discharge water from the waterlift discharge port to the hole, waste of water is prevented.
The blocking means expands when supplied with air, and may have an air supply passage leading to the blocking means (Claim 2).
In the high-pressure injection method, when the improvement material is injected, the reach of the improvement material is extended by injecting the air in the form of enveloping the improvement material to be injected as is known in the art, so the cutting ability of the ground is increased. improves. Also, slime discharge is promoted by air lift.
Since the blocking means expands using the air for taking such an effective action and blocks the water supply passage, the functionality of the ground improvement monitor is improved.
The invention according to claim 3 is characterized in that the ground improvement monitor according to any one of claims 1 to 2 and a rod are connected and integrated. In this case, the same actions and effects as those of the first and second aspects of the invention can be exhibited.
According to a fourth aspect of the present invention, the ground improvement device according to any one of the first to third aspects includes an improvement material supply passage for supplying an improvement material, and the ground improvement device while supplying water to the water supply passage. A hole drilling step for drilling the ground using a step, a blocking step for operating the blocking means to block the water supply passage, and supplying an improvement material to the improvement material supply passage to inject or inject the improvement material to the ground. And an injection / injection step. In this case, the same actions and effects as those of the first to third aspects of the invention can be exhibited.

In the present invention, as described above, the water supply passage is blocked by expansion, and the reversible operating shut-off means is provided on the wall surface forming the water supply passage. It is possible to create an improved diameter and shorten the working time.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 (a) shows an example of the ground improvement device 1 of the present invention. The ground improvement device 1 includes, for example, a triple tube 2 and a monitor 3, and the triple tube 2 is integrated with the monitor 3, for example, in an axial direction at one end thereof. The other end of the triple tube 2 is, for example, screwed with another triple tube 2 not shown in the axial direction. As shown in FIG. 1B, the ground improvement device 1 is inserted into the ground with the monitor 3 at the head. Hereinafter, the direction proceeding to the monitor 3 along the axis of the ground improvement device 1 is referred to as the head direction, and the direction proceeding in the opposite direction is referred to as the tail direction. Further, a position advanced from the arbitrary point toward the head is referred to as a head side, and the opposite side is referred to as a tail side.

  As shown in FIG. 1A, the triple tube 2 includes an outer tube 24, an intermediate tube 25, and an inner tube 26. The space between the inner surface of the outer tube 24 and the outer surface of the middle tube 25 forms a water supply passage 27 for supplying water, and the space between the inner surface of the middle tube 25 and the outer surface of the inner tube 26 is the ground. An air supply passage 28 for supplying air for improving the cutting ability and promoting the discharge of slime by air lift and for expanding the packer as the blocking means 12 described later is formed, and the inside of the inner pipe 26 is an improved material. The improvement material supply passage 29 for supplying the gas is formed.

  The monitor 3 includes an outer tube 4, an intermediate tube 5, and an inner tube 6. The space between the inner surface of the outer tube 4 and the outer surface of the middle tube 5 forms a water supply passage 7 for supplying water, and the space between the inner surface of the middle tube 5 and the outer surface of the inner tube 6 will be described later. For example, an air supply passage 8 for supplying air for inflating the packer as the blocking means 12 is formed, and an improvement material supply passage 9 for supplying the improvement material is formed inside the inner tube 6.

  The outer tube 4, the middle tube 5 and the inner tube 6 of the monitor 3 are connected to the outer tube 24, the middle tube 25 and the inner tube 26 of the triple tube 2, respectively. Further, the water supply passage 7, the air supply passage 8, and the improvement material supply passage 9 of the monitor 3 communicate with the water supply passage 27, the air supply passage 28, and the improvement material supply passage 29 of the triple pipe 2.

  The outer pipe 4 is provided with a water lift discharge port 4a from the inner surface, and is provided with a differential pressure valve fitting hole 4b communicating with the water lift discharge port 4a from the outer surface. The cross section of the differential pressure valve fitting hole 4b is larger than the cross section of the water lift discharge port 4a, and the water lift discharge port 4a communicates with the differential pressure valve fitting hole 4b on the rear side from the center of the cross section of the differential pressure valve fitting 4b. Yes.

  With the differential pressure valve 10 fitted into the differential pressure valve fitting hole 4b and completely covering the water lift discharge port 4a from the outside, the front side from the water lift discharge port 4a by the differential pressure valve fixing member 11 such as a pin. It is fixed to the outer tube 4 with For example, a leaf spring 10 is used as the differential pressure valve 10. In this case, the operating pressure is designed and adjusted according to standards and materials such as the thickness and size of the leaf spring 10 and the installation position of the differential pressure valve fixing member 11. The

  The middle pipe 5 is provided with an air discharge port 5a on the front side of the water lift discharge port 4a. A blocking means 12 such as a rubber packer is attached to the outer surface of the middle pipe 5 on the front side from the water lift discharge port 4a, and completely covers the air discharge port 5a. Therefore, the air supply passage 8 and the interior of the packer 12 communicate with each other via the air discharge port 5a.

  For example, a metal crown 3a for drilling the ground is screwed to the tip of the monitor 3 at the other end of the monitor 3 which is screwed with the triple tube 2, and for example in the circumferential direction of the tip of the metal crown 3a. Are provided with a plurality of hard chips 3c. The tip 3c usually has a hexagonal or quadrangular cross-sectional shape, and is properly used depending on the soil to be drilled. A drilling outlet 3b is provided around the center of the end of the monitor 3 so as to be surrounded by the metal crown 3a. A check valve 13 is attached so as to cover the hole discharge port 3b from the outside, for example, so that unnecessary materials such as earth and sand and improvement material do not flow backward from the hole discharge port 3b.

  The check valve 13 is, for example, a short hose-like rubber. In this case, the reverse support valve completely covers the drilling discharge port 3b so that the earth and sand and the improving material do not flow backward, and a bolt (not shown) discharges the drilling hole. It is fixed to the outer tube 4 from the distal end side with respect to the outlet 3b. The reverse support valve 13 has a function as a high check valve with respect to the pressure from the outside, but is weak against the force from the inside and has a very weak function as the differential pressure valve, which is sufficiently higher than the operating pressure of the differential pressure valve 10. It is set to low pressure. As shown in FIG. 2 (b), the differential pressure valve 10 does not open even when water is discharged from the drilling outlet 3b to the ground during drilling.

  For example, a nozzle 15 for improving material is attached to the front end portion of the inner tube 6 in a direction substantially orthogonal to the axis of the inner tube 6. The improvement material nozzle 15 is formed with an improvement material injection port 15 a in a direction substantially orthogonal to the axis of the inner tube 6. The outer surface of the improvement material nozzle 15 is formed so that the cross section perpendicular to the axis of the improvement material nozzle 15 decreases toward the tip, that is, the outer surface of the improvement material nozzle 15 approaches the axis of the improvement material nozzle 15 toward the outside. .

  For example, an air nozzle 16 is attached to the outer surface of the improvement material nozzle 15 in a direction substantially orthogonal to the axis of the intermediate tube 6 at the front end portion of the intermediate tube 5. The air nozzle 16 is formed with an air injection port 16a so that the air to be injected is directed to the axis of the improvement material injection port 15a. Since the air nozzle 16 is attached to the outer surface of the improvement material nozzle 15, the inclination of the air nozzle 16 is the same as the inclination of the outer surface of the improvement material nozzle 15.

  Since the blocking means 12 is, for example, a rubber packer, it can be deformed following the unevenness in the operating state. Therefore, even if the inner surface of the outer tube 4 has irregularities due to erosion or deformation, the blocking means 12 adheres to the inner surface of the outer tube 4 according to the irregularities and completely blocks the water supply passage 7.

  The allowable pressure of the packer 12 is set to be equal to or higher than the injection pressure of the air nozzle 16. Therefore, when air is ejected from the air nozzle 16, the packer 12 maintains an expanded state at the same pressure as the air discharge pressure without rupturing.

  The operating pressure of the differential pressure valve 10 is set to be equal to or lower than the discharge pressure of the air nozzle 16. Since the inside of the packer 12 and the air injection port 16 a communicate with each other, the maximum pressure of the packer 12 is when air is injected from the air nozzle 16. Therefore, when air is injected from the air nozzle 16 and the packer 12 is expanded, water is supplied to the water supply passage 7 and the pressure in the water supply water passage 7 reaches the operating pressure of the differential pressure valve 10. Water is discharged from the discharge port 4a for water lift without deformation of the 12.

  Next, an example of ground improvement work to which the high-pressure jet stirring method using the ground improvement apparatus 1 of the present invention is applied will be described.

  As shown in FIG. 2 (a), the ground improvement device 1 connected to the high-pressure hose 18 through the swivel 17 at one end of the triple pipe 2 is propelled to the target depth while being rotated by a known drilling machine 19. Drill holes. During drilling, water is pumped into the water supply passage 7 to discharge water from the drilling discharge port 3b to the ground. The target depth coincides with the target deepest point P1 (the lowest point in the figure) of the improved body 20 to be created, for example.

  One end of the high-pressure hose 18 is connected to each of the outer tube 24, the middle tube 25, and the inner tube 26 of the triple tube 2 via the swivel 17, and the other end is connected to a known facility (not shown). Yes. The well-known equipment not shown includes equipment for measuring pressure and flow rate, and can measure the pressure and flow rate of water, air and improvement material supplied to the ground improvement device 1. .

  As described above, since the operating pressure of the check valve 13 is set to be lower than the operating pressure of the differential pressure valve 10, only the check valve 13 is operated in a state where the differential pressure valve 10 is not operated as shown in FIG. Is activated, and water is discharged toward the head only from the hole discharge port 3b. If the length of the ground improvement device 1 is insufficient during drilling, another triple pipe 2 is added between the rear end of the triple pipe 2 protruding above the ground and the swivel 17 to improve the ground. The device 1 is extended.

  Next, as shown to Fig.3 (a), it raises to the target depth, rotating the ground improvement apparatus 1, and the improvement body 20 is created. The target depth matches, for example, the target shallowest point P2 (the highest point in the figure) of the improved body to be created. During this time, the improvement material supply passages 29 and 9 are supplied with an improvement material such as a cement-based hardener, the air is supplied to the air supply passages 28 and 8, and the air is combined with the improvement material to inject the improvement material at a high pressure. At the same time as forming a cavity in the ground, the improved material and the cut earth and sand are stirred in the formed cavity. The mixture of the improving material and the earth and sand stirred in the cavity is hardened to form the improved body 20.

  Further, water is supplied to the water supply passages 27 and 7 while the improving material 20 is formed, and water is jetted upward from the waterlift discharge port 4a. Since the water pushes up the slime between the outer surface of the ground improvement device 1 and the hole wall of the hole 21 to the ground, the discharge of the slime can be promoted. In this way, water that was discharged downward during drilling can be switched during injection and discharged upward from the water lift outlet to promote slime discharge and ensure the finished product quality and quality. it can.

  After the drilling is completed, the pumping of water is stopped once, and as shown in FIG. 3B, air is supplied to the air supply passages 28 and 8 to operate the blocking means 12 and at the same time from the air injection port 16a to the ground. Inject air. The actuated packer 12 is spread and closely follows the inner surface of the outer tube 4 at the same pressure as the air nozzle 16 injection pressure, and the water supply passage 7 is connected to the water lift discharge port 4a and the hole discharge port. Shut off from the outlet 3b. As a result, the water supplied to the water supply passage 7 is discharged from the water lift discharge port 4a only to the ground. At this time, the improvement material is supplied to the improvement material supply passages 29 and 9 and the improvement material is injected to the ground from the improvement material injection port 15a.

  Next, water is again pumped into the water supply passages 27 and 7 to operate the differential pressure valve 10. The differential pressure valve 10 is composed of a leaf spring 10 and is fixed to the fixing means 11 on the leading side from the water lift discharge port 4a. Therefore, the surface facing the outer tube 4 of the leaf spring 10 bent by the pressure of water. A space S1 is formed on the outer surface of the outer tube 4 with an opening on the rear side. Accordingly, water is jetted from the water lift discharge port 4a and the differential pressure valve fitting hole 4b substantially toward the rear side.

  The improved material supplied to the improved material supply passages 29 and 9 is ejected from the improved material nozzle 15. The air jetted from the air injection port 16a attached to the outer surface of the improvement material nozzle 15 is jetted in a form of enveloping the improvement material, thereby extending the reach of the improvement material and promoting the slime discharge by the air lift. . As described above, it is possible to promote the slime discharge by using the air supplied to the same route and to further promote the slime discharge by switching the water route of the water supply passage 7.

  When the improvement body 20 is completed, the supply of the improvement material to the improvement material supply passages 29 and 9, the supply of air to the air supply passages 28 and 8, and the supply of water to the water supply passages 27 and 7 are stopped. As shown in FIG. 4A, the ground improvement device 1 is pulled out. Since the supply of air to the air supply passages 28 and 8 is stopped, as shown in FIG. 4B, the packer 12 is contracted and closed. The blocking of the path to the discharge outlet 3b is released, and the state is switched to a state where a hole can be drilled.

  Next, if there is a place where the ground improvement work is carried out, drilling / improvement is created at the next construction place. Since the water supply passage 7 is switched to a state in which drilling can be performed, the ground improvement device 1 can be used in the next construction location as it is. Thus, since the ground improvement device 1 can be switched between the drilling state and the improved body creation state by the air supply operation, Patent Document 1 describes the transition from one construction location to another construction location. The work of collecting steel balls as described is not necessary, and the construction time can be shortened.

(Other embodiments)
The present invention is not limited to the above embodiments. The above-described embodiment is merely an example, and any structure having substantially the same configuration as the technical idea described in the claims of the present invention and having the same function and effect can be used. It is included in the technical scope of the present invention.

  As described above, the present invention is not limited to the ground improvement work to which the high-pressure jet stirring method is applied, but can also be used for the ground improvement work to which the chemical solution injection method is applied.

  In addition to drilling a vertical hole in a horizontal ground and creating the improved body 20, it is also possible to drill a slanted hole in a vertical ground and create an improved body. The present invention can also be applied to the construction of

  Further, it is possible to drill a hole as the target shallowest point of the improved body 20 that creates the target depth for drilling, and to create the improved body as the target deepest point of the improved body 20 that creates the target depth of the improved body. is there.

  The blocking means 12 may be manufactured from a sheet of Kepler fiber, aramid fiber, carbon fiber or the like in addition to propylene fiber, and may be expanded as long as it is supplied with air and can be deformed according to unevenness.

  The material supplied to the water supply passage after completion of drilling is, for example, a thickener or dispersant to reduce slime viscosity in the case of viscous soil, and a thickener to prevent sedimentation in the case of gravelly soil. Stabilizing liquid or air can be used.

  Although a leaf spring is fixed to the outer surface of the outer tube 4 as the differential pressure valve 10, a cap that opens at a predetermined pressure can be fitted to the waterlift discharge port 4a. Similarly, the check valve 13 can be fitted with a cap that opens at a predetermined pressure in the hole discharge port 3b.

(A) is sectional drawing which shows an example of a ground improvement apparatus, (b) is the front view which showed the condition which started drilling using the ground improvement apparatus of Fig.1 (a). (A) is the front view which showed the condition which drills using the ground improvement apparatus of Fig.1 (a), (b) is the principal part enlarged view of the ground improvement apparatus of Fig.2 (a). (A) is the front view which showed the condition which injected the improvement material and air into the ground at high pressure using the ground improvement apparatus of FIG. 1 (a), (b) is a principal part cross section of the ground improvement apparatus of FIG. 3 (a). FIG. (A) is the front view which showed the condition which pulls out the ground improvement apparatus of Fig.1 (a), (b) is principal part sectional drawing of the ground improvement apparatus of Fig.4 (a).

Explanation of symbols

1 ……… Ground improvement device 2 ……… Mie tube (rod)
3 ... …… Monitor 3a …… Metal crown 3b …… Drilling outlet 3c …… Chip 4 ………… Monitor outer pipe 4a …… Water lift outlet 4b …… Differential pressure valve fitting hole 5 ………… Monitor inner pipe 5a ... Air outlet 6 ... Monitor inner pipe 7 ... Monitor water supply passage 8 ... Monitor air supply passage 9 ... Monitor improvement material supply passage 10 ... Plate Spring (differential pressure valve)
11 …… Differential pressure valve fixing member 12 …… Blocking means (packer)
13 ... Leaf spring (check valve)
15 ... Improvement material nozzle 15a ... Improvement material injection port 16 ... Air nozzle 16a ... Air injection port 17 ... Swivel 18 ... High pressure hose 19 ... Drilling machine 20 ... Improvement body 21 ... Drilling hole 24 …… Triple tube (rod) outer tube 25 …… Triple tube (rod) middle tube 26 …… Triple tube (rod) inner tube 27 …… Triple tube (rod) water supply passage 28 …… Triple tube ( (Rod) air supply passage 29 ... triple pipe (rod) improvement material supply passage S1 ... space P1 ... target shallowest point P2 ... target deepest point

Claims (4)

A ground improvement monitor connected to a rod, which is used for drilling the ground in the ground improvement work and injecting or injecting the improvement material into the ground,
A water supply passage for supplying water;
A hole discharge port for discharging water to the ground is formed on the wall surface forming the water supply passage,
A blocking means that reversibly deforms and closes and blocks the wall surface is provided on the wall surface upstream of the drilling outlet ,
A water lift discharge port for discharging the water supplied to the water supply passage to the ground is provided upstream of the blocking means of the wall surface forming the water supply passage,
A check valve for preventing the material from entering the water supply passage from the hole discharge port is attached to the hole discharge port,
A differential pressure valve that prevents intrusion of a substance from the water lift discharge port into the water supply passage is attached to the water lift discharge port,
The ground improvement monitor characterized in that the operating pressure of the check valve is lower than the operating pressure of the differential pressure valve . The blocking means expands when air is supplied,
The ground improvement monitor according to claim 1, further comprising an air supply passage leading to the blocking means. The ground improvement device according to claim 1, wherein the ground improvement monitor and the rod are connected and integrated. The ground improvement monitor according to any one of claims 1 to 3 , further comprising an improvement material supply passage for supplying the improvement material,
Drilling step of drilling the ground using the ground improvement monitor while supplying water to the water supply passage;
A blocking step of operating the blocking means to block the water supply passage;
A ground improvement construction method comprising: an injection injection step of supplying an improvement material to the improvement material supply passage and injecting or injecting the improvement material into the ground.

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