JP7060402B2 - Mud collection device and ground improvement method - Google Patents

Description

The present invention relates to a mud collecting device and a ground improvement method.

As a method of performing liquefaction countermeasure work (ground improvement) below the existing structure, a columnar improved body may be formed by a high-pressure injection stirring method. In the high-pressure injection stirring method, by injecting a solidifying material or the like into the ground at high pressure, the ground is cut and the solidifying material is agitated and mixed, so that mud is generated. Further, in the high-pressure injection stirring method, since a guide hole for arranging the injection rod for injecting the solidifying material in the ground is formed, the mud is ejected from the guide hole. Therefore, Patent Document 1 discloses a method of taking the mud into a mud receiving tank provided at the hole opening of the guide hole so that the mud ejected from the guide hole does not scatter to the surroundings. There is.
However, when the ground is improved on the ground below the existing structure, it may not be possible to secure a space for installing the mud drainage tank around the guide hole. In such a case, a mud collecting device to which a mud drain pipe is connected is provided at the hole opening of the guide hole, and the mud is transported to a predetermined position through the mud collecting device.

JP-A-2010-229729

The geology, hardness, viscosity, etc. of the mud generated by the high-pressure injection stirring method differ depending on the stratum and the like. If the mud has a high viscosity, the mud collecting device may be blocked. If the mud collection device is blocked, it takes time and effort because it is necessary to interrupt the construction and remove the obstacles. Further, when the wastewater collecting device is blocked, the pressure in the ground increases, and the foundation ground rises, which may cause displacement of the existing structure.
From such a viewpoint, it is an object of the present invention to propose a mud collecting device and a ground improvement method capable of efficiently discharging the mud generated at the time of ground improvement by the high pressure injection stirring method.

The present invention for solving the above-mentioned problems is a wastewater collecting device provided at a hole opening of a guide hole of a high-pressure injection stirring method, and has a tubular device body through which an injection rod is inserted and the device body. It is provided with a discharge port formed on the side surface for discharging the waste mud and an intake port formed on the side surface of the device body for taking in diluted water, and the water intake port is a central portion of the device body. A flow path that guides the diluted water taken in from the intake port to the discharge port between the outer surface of the injection rod and the inner surface of the device main body , which is formed at a position facing the discharge port. Is characterized by being formed. In the mud collecting device, it is desirable that the intake ports are formed at two places, and the two intake ports and the discharge ports are arranged in a Y shape.

Further, the ground improvement method using the mud collecting device includes a work of installing the mud collecting device at the hole opening of the guide hole and a work of inserting an injection rod inserted into the main body of the device into the guide hole. It includes the work of forming a columnar improved body on the ground by injecting a solidifying material from the injection rod into the ground around the guide hole at high pressure, and supplies diluted water to the apparatus main body from the intake port. As a result, a flow from the intake port to the discharge port is formed in the main body of the apparatus, and the waste mud ejected from the guide hole due to the high-pressure injection of the solidifying material is discharged from the discharge port together with the diluted water. It is characterized by that.

According to the mud collecting device and the ground improvement method of the present invention, since the mud is discharged using the diluted water, the inside of the device is prevented from being blocked by the mud. That is, since the flow of the diluted water is formed inside the main body of the apparatus, the mud ejected from the guide hole is not guided to the discharge port and stays inside the main body of the apparatus. Further, since the hole opening portion of the guide hole is in a negative pressure state due to the flow of the diluted water from the intake port to the discharge port, the drainage mud is sucked from the guide hole to the apparatus main body and can be efficiently discharged. Further, even when the viscosity of the waste mud is high, it is diluted with diluted water, so that it is prevented from adhering to the inside of the main body of the apparatus.

According to the mud collecting device and the ground improvement method of the present invention, it is possible to efficiently discharge the mud generated during the ground improvement by the high pressure injection stirring method.

It is sectional drawing which shows the construction state of the ground improvement method which concerns on this embodiment. It is a figure which shows the waste mud collecting apparatus of this embodiment, (a) is a front view, (b) is a plan view. It is a top view of the wastewater collecting apparatus which concerns on other forms.

In the present embodiment, a case where the ground improvement body 2 is formed on the ground G below the existing structure 1 by the high-pressure injection stirring method will be described.
The existing structure 1 of the present embodiment is a so-called caisson, which is a box-shaped concrete member buried in the ground. The existing structure 1 forms a railroad platform. In the present embodiment, the solidifying material is jetted and agitated to the ground G by using the injection rod 3 arranged so as to penetrate the bottom slab of the existing structure 1 from the side of the track during the time zone from the last train to the first train. As a result, the ground improvement body 2 is formed. The injection and stirring of the solidifying material is performed while adjusting the amount of injection into the ground G and the amount of mud discharged from the ground G so that the existing structure 1 is not displaced due to the increase in the pressure inside the ground. .. The existing structure 1 is not limited to the caisson.

In the ground improvement method of the present embodiment, the construction machine 4 installed inside the existing structure 1 is used to drill holes in the guide hole 5 and inject and stir the solidifying material. The waste mud D generated by the construction is discharged to the outside of the existing structure 1. In the present embodiment, the mud drainage D is temporarily stored in the primary receiving tank 41 provided inside the existing structure 1 and then transported to the mud drainage tank 42 provided on the ground portion. The mud D stored in the mud drain tank 42 is carried out of the site (disposal site, etc.) using a transport vehicle or the like. In FIG. 1, reference numeral 11 is a shaft used for carrying in and out of equipment (construction machine 4, injection rod 3 and the like) necessary for construction, and for piping of the mud drain pipe 43 and the like. The shaft 11 may be formed as needed. Further, the primary receiving tank 41 may be provided as needed, and when the primary receiving tank 41 is omitted, the mud drainage D may be discharged directly to the above-ground portion via the mud drainage pipe 43.

Hereinafter, the ground improvement method of the present embodiment will be described.
First, boring is performed using the construction machine 4 installed on the bottom slab of the existing structure 1 to form the guide hole 5. As shown in FIG. 2A, a mouth pipe 51 is provided at the upper end of the guide hole 5.
After forming the guide hole 5, the mud collecting device 7 is fixed to the upper end (hole opening) of the guide hole 5 via the valve 6.
The valve 6 is a member that opens and closes the hole opening (upper end) of the guide hole 5. In the present embodiment, a gate valve having a sluice valve is adopted as the valve 6, but the configuration of the valve 6 is not limited, and may be, for example, a ball valve. The valve 6 is fixed to the guide hole 5 via the mounting pipe 52 attached to the mouth pipe 51. The mounting pipe 52 is made of a pipe material having the same inner diameter as the mouth pipe 51. The mounting pipe 52 may be provided as needed, and the valve 6 may be directly fixed to the mouth pipe 51. The valve 6 is arranged in a pit 12 formed on the side of the track. The pit 12 is formed in a frame shape and surrounds the valve 6. The upper end of the pit 12 is lower than the upper surface of the railroad track, and is configured so as not to hinder the passage of vehicles. The pit 12 may be formed as needed.

As shown in FIGS. 2A and 2B, the wastewater collecting device 7 discharges the device main body 71 through which the injection rod 3 is inserted and the drainage port D formed on the side surface of the device main body 71. 72, an intake port 73 formed on the side surface of the apparatus main body 71 to take in the diluted water W, and a prebender 74 formed on the upper portion of the apparatus main body 71 are provided.
The apparatus main body 71 is composed of a cylindrical member having an inner diameter larger than the outer diameter of the injection rod 3. The upper and lower ends of the apparatus main body 71 are open. The lower end of the apparatus main body 71 is fixed to the upper end of the valve 6, and the prebender 74 is fixed to the upper end of the apparatus main body 71.
The prebender 74 is an annular member having a through hole through which the injection rod 3 can be inserted. A rubber material, a resin material, or the like is installed on the inner surface of the through hole, and is configured to be in close contact with the outer surface of the injection rod 3 when the injection rod 3 is inserted through the through hole. That is, the prebender 74 is a water blocking member for preventing the mud drainage D and the like from flowing out along the outer surface of the injection rod 3. The center of the prebender 74 coincides with the axis of the apparatus main body 71. The configuration of the pre-bender 74 is not limited.

The discharge port 72 is a branch pipe formed on the side surface of the apparatus main body 71, and is configured so that the mud drain pipe 43 can be connected. The discharge port 72 guides the mud drain D ejected from the guide hole 5 to the mud drain pipe 43. The inner diameter of the discharge port 72 is not limited, but the size may be such that at least an inner space area larger than the area of the gap formed between the inner surface of the guide hole 5 and the outer surface of the injection rod 3 can be secured. preferable.
The water intake port 73 is a branch pipe formed on the side surface of the device main body 71, and is configured so that a water pipe 75 extending from a water storage tank (not shown) can be connected. The water pipe 75 is a pipe for pumping the diluted water W. In this embodiment, the case where the diluted water W is collected from the water storage tank will be described, but the diluted water W may be obtained from the water supply. The water storage tank may be arranged inside the existing structure 1 or may be arranged above the ground. The intake port 73 of the present embodiment is formed at a position facing the discharge port 72 with the central portion of the apparatus main body 71 interposed therebetween. That is, the central axis of the intake port 73 and the central axis of the discharge port 72 are arranged on the same straight line. The water intake port 73 does not necessarily have to be arranged on the extension line of the discharge port 72, and may be attached diagonally to the central axis of the discharge port 72.

After fixing the waste mud collecting device 7 to the hole opening of the guide hole 5, the injection rod 3 is inserted into the guide hole 5. The injection rod 3 is inserted into the guide hole 5 through the prebender 74 and the apparatus main body 71. Since the center of the pre-bender 74 and the central axis of the device main body 71 are aligned with each other, the injection rod 3 through which the pre-bender 74 is inserted is arranged at the center of the device main body 71. That is, a gap having a constant width is formed between the outer surface of the injection rod 3 and the inner surface of the apparatus main body 71.

After the injection rod 3 is inserted into the guide hole 5, the solidifying material is injected at high pressure from the injection rod 3 to the ground G around the guide hole 5. At this time, the solidifying material is injected while rotating the injection rod 3. By doing so, the ground G around the guide hole 5 is cut by the solidifying material injected at high pressure, and the solidifying material is agitated and mixed in the ground G. 2 is formed.
Diluted water W is supplied from the intake port 73 into the apparatus main body 71 as the solidifying material is sprayed and stirred. The diluted water W taken in from the water intake port 73 flows to the discharge port 72 through the gap between the injection rod 3 and the apparatus main body 71. That is, the gap between the inner surface of the apparatus main body 71 and the outer surface of the injection rod 3 serves as a flow path for guiding the diluted water W taken in from the intake port 73 to the discharge port 72, and the flow path is a flow path from the intake port 73 to the discharge port. A flow towards 72 is formed.

When the solidifying material is injected at high pressure into the ground G, the pressure inside the ground in the ground G rises, so that the waste mud D flows into the gap between the guide hole 5 and the injection rod 3 from the inside of the ground G. The waste mud D is ejected into the apparatus main body 71 due to the pressure inside the ground. Further, since the flow of the diluted water W from the intake port 73 to the discharge port 72 is formed in the device main body 71, the upper end portion of the guide hole 5 (the joint portion between the valve 6 and the wastewater collection device 7) is formed. , It becomes a state of negative pressure. Therefore, the mud drainage D in the guide hole 5 is sucked into the apparatus main body 71. The waste mud D that has entered the apparatus main body 71 is discharged from the discharge port 72 together with the diluted water W. The mud D discharged from the discharge port 72 is transported to the primary receiving tank 41 via the mud drain pipe 43, and then discharged to the mud drain tank 42 above the ground.

When the injection and stirring of the solidifying material are completed, the valve 6 is closed to shield the hole of the guide hole 5. After closing the valve 6, the mud collecting device 7 is removed. The timing of closing the valve 6 is not limited, and the valve 6 may be closed after confirming that the earth pressure in the ground G is stable. Further, the mud collecting device 7 may be left behind even after the valve 6 is closed.
After curing the ground improvement body 2, the valve 6 and the mounting pipe 52 and the like are removed.

As described above, according to the mud collecting device 7 and the ground improvement method of the present embodiment, the mud D is discharged using the diluted water W, so that the inside of the mud collecting device 7 is prevented from being blocked by the mud D. Has been done. That is, since the flow due to the diluted water W is formed inside the apparatus main body 71, the waste mud D ejected from the guide hole 5 is not guided to the discharge port 72 and stays inside the apparatus main body 71. .. Further, since the waste mud D does not scatter to the surroundings, the cleaning work of the construction area can be minimized. As a result, workability is improved, construction costs can be reduced, and the construction period can be shortened.
Since the injection rod 3 is arranged at the center of the apparatus main body 71, the gap between the outer surface of the injection rod 3 and the inner surface of the apparatus main body 71 exhibits an annular shape having a constant width. Therefore, a portion where the width of the gap is narrowed, a corner portion, or the like is not formed inside the apparatus main body 71, and therefore, the waste mud D is less likely to be clogged.
Further, since the waste mud D can be efficiently discharged, the amount of diluted water W can be minimized. Therefore, it is possible to reduce the amount of mud discharged, and by extension, it is possible to reduce the labor and cost required for disposing of the waste mud D.

Further, since the hole opening portion of the guide hole 5 is in a negative pressure state due to the flow of the diluted water W from the intake port 73 to the discharge port 72, the waste mud D is sucked from the guide hole 5 to the apparatus main body 71, which is efficient. The waste mud D can be discharged.
Further, even when the viscosity of the waste mud D is high, the waste mud D is diluted with the diluted water W, so that the waste mud D is prevented from adhering to the inside of the apparatus main body 71.
Since the water intake port 73 is formed at a position facing the discharge port 72 with the injection rod 3 interposed therebetween, the diluted water W flowing in from the water intake port 73 is divided into two by the injection rod 3 and then the injection rod 3 is used. It goes around and flows to the discharge port 72. Therefore, since the flow of the diluted water W is formed over the entire collection of the injection rods 3, the mud D that has entered the inside of the mud collecting device 7 can be reliably discharged.

Since the hole opening of the guide hole 5 can be opened and closed by the valve 6, the construction can be interrupted and restarted. If construction can only be carried out during a limited time period, such as in service railways and roads, construction may not be completed within the time limit. Therefore, if the guide hole 5 is shielded by the valve 6, the mud collecting device 7 and the construction machine 4 can be removed to open the railroad or the road. At this time, since the valve 6 is arranged in the pit 12, it does not obstruct the passage of the vehicle.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-mentioned constituent elements can be appropriately changed without departing from the spirit of the present invention.
In the above embodiment, the case where the existing structure 1 is a caisson has been described, but the existing structure 1 is not limited to the caisson. For example, it may be a tunnel, a box culvert, a pavement, a building, or the like. Further, the existing structure 1 is not limited to railway facilities.

In the above embodiment, the case where the intake port 73 is formed on the extension line of the discharge port 72 has been described, but the height positions of the discharge port 72 and the intake port 73 may be different. Further, in the above embodiment, the case where the intake port 73 is formed in one place in the apparatus main body 71 has been described, but the number of the intake ports 73 formed in the apparatus main body 71 is not limited, and a plurality of intake ports 73 are formed. It may have been done. For example, as shown in FIG. 3, the intake 73 may be formed at two locations. At this time, the two intake ports 73, 73 and the discharge port 72 are arranged in a Y shape so that the flow of the diluted water W taken in from the intake port 73 is in the direction of the discharge port 72 (two intake ports). It is desirable that the intake port 73 opens toward the discharge port 72 by intersecting the normal line passing through the centers of 73 and 73 and the normal line passing through the center of the discharge port 72 in a Y-shape in a plan view).
Further, when a plurality of intake ports 73 are formed, the height positions of the intake ports 73 may be different.

Further, in the above embodiment, the guide hole 5 is substantially vertical, but the guide hole 5 may be inclined.
In the above embodiment, the case where the mud collecting device 7 is attached to the hole opening of the guide hole 5 via the valve 6 has been described, but the valve 6 is omitted and the mud collecting device 7 is directly attached to the guide hole 5. May be good.
Further, if the dispersant is mixed in the diluted water W, the fluidity of the highly viscous mud D can be improved, and the workability is further improved.

Further, a pressure gauge for measuring the internal pressure may be installed in the apparatus main body 71. By doing so, since the increase / decrease in the pressure in the device main body 71 can be confirmed by the pressure gauge, it is possible to confirm the presence / absence of the blockage in the device main body 71. Further, by adjusting the amount of diluted water W according to the measured value of the pressure gauge, more efficient construction becomes possible. That is, when the blockage in the apparatus main body 71 is confirmed by the measured value of the pressure gauge, the amount of the diluted water W is adjusted to promote the flow of the waste mud D. Further, the amount of diluted water W may be automatically adjusted according to the measured value of the pressure gauge.

The device main body 71 may be formed of a square tubular member.
Further, it is desirable to install the mud collecting device 7 so that the discharge port 72 of the mud collecting device 7 is located at a position higher than the groundwater level. By doing so, it becomes possible to carry out high-pressure jet agitation below the groundwater level, and workability is improved.

1 Existing structure 2 Ground improvement body 3 Injection rod 4 Construction machine 5 Guide hole 6 Valve
7 Mud collection device 71 Device body 72 Outlet 73 Intake port D Mud drain G Ground W Diluted water

Claims (2)

It is a mud collection device installed at the hole opening of the guide hole of the high-pressure injection stirring method.
The cylindrical device body through which the injection rod is inserted, and
A discharge port formed on the side surface of the main body of the device to discharge the waste mud,
It is provided with an intake port formed on the side surface of the main body of the device to take in diluted water.
The water intake port is formed at a position facing the discharge port with the central portion of the device main body interposed therebetween.
A mud drainage collecting device, characterized in that a flow path for guiding diluted water taken in from the intake port to the discharge port is formed between the outer surface of the injection rod and the inner surface of the device main body. The work of installing the mud collecting device according to claim 1 at the hole opening of the guide hole, and
The work of inserting the injection rod inserted into the apparatus main body into the guide hole, and
A ground improvement method comprising the work of forming a columnar improved body on the ground by injecting a solidifying material from the injection rod into the ground around the guide hole at high pressure, from the intake port to the apparatus main body. By supplying the diluted water, a flow from the intake port to the discharge port is formed in the main body of the apparatus, and the waste mud ejected from the guide hole due to the high-pressure injection of the solidifying material is discharged together with the diluted water. A ground improvement method characterized by discharging from a discharge port.

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