JP2020084485A - Ground improvement device, ground improvement system, and ground improvement method - Google Patents

Abstract

To provide a ground improvement device, and a ground improvement method capable of improving a water bottom ground without requiring a press-in configuration toward the water bottom ground and a stir configuration stirring the water bottom ground.SOLUTION: A ground improvement device 1 is suspended in water with a wire 22 connected on its upper surface, penetrating in a soft weak layer 51 by its own weight after touching a surface of the soft weak layer 51. An operator instructs a lifting device to lift up the ground improvement device 1 when recognizing that the ground improving device 1 has descended to a determined distance from the touched surface of the soft weak layer 51. The lifting device lifts the ground improving device 1 by winding up the wire 22. A space S is created along a track below the ground improvement device 1 to be lifted. A supply device supplies a ground improvement material to the ground improvement device 1 through a hose 32 at a supplying speed in accordance with a lifting-up speed of the ground improvement device 1. The ground improvement material is discharged downward from a discharge port 11, the space S being filled with the ground improvement material.SELECTED DRAWING: Figure 3

Description

The present invention relates to a ground improvement device, a ground improvement system, and a ground improvement method.

Deep sea resources such as methane hydrate, rare earths, and hydrothermal deposits exist in the deep sea near Japan. There are various methods for collecting deep-sea resources, and for example, there is also a method for extracting resources in the ground by excavating the seabed ground with an excavator installed on the seabed.

However, there are some ultra-soft grounds having a shear strength of about 2 to 10 kilopascals on the deep sea floor, which may not be suitable for installing and running heavy equipment such as an excavator. When using heavy equipment on ultra-soft ground, it is necessary to secure its transportability, bearing capacity and stability, and it is necessary to improve the ground on which heavy equipment is installed.

Examples of techniques for improving soft soil in water include the techniques described in Patent Documents 1 and 2. The technique described in Patent Document 1 is to solve the problem that when the solidifying material is added to the water-containing soft soil, the rotating stirring blade moves up and down the water-containing soft soil, so that the water-containing soft soil floats up and pollutes water. belongs to. In Patent Document 1, an inverted bottomed cylindrical shell is provided at the lower end of a frame body to be lowered from a hull, a stirring blade is arranged in the inverted bottomed cylindrical shell, and after the bottoming, the stirring blade is attached to a water-containing soft soil. The method of making it penetrate into is described.

Further, in Patent Document 2, in order to maintain a constant inclination angle and position of a ground improvement machine suspended in water by a wire from a turret provided on the hull, the ground improvement machine is provided with a telescopic clamp device. A technique is disclosed in which the stroke of the telescopic clamp device is restrained and the stroke of the telescopic clamp device is controlled according to changes in the inclination and position of the hull.

Japanese Patent Laid-Open No. 61-1718 JP, 60-233223, A

However, both of the techniques of Patent Documents 1 and 2 require a configuration in which the ground improvement device is pushed toward the bottom of the water and a configuration in which cement slurry or the like is supplied and agitated together with the bottom of the ground, so that the water depth is, for example, 300. It is difficult to apply to the improvement of deep-sea floors more than a meter.

One of the objects of the invention of the present application is to improve a water bottom ground without requiring a configuration of pushing toward the water bottom ground and a configuration of stirring the water bottom ground.

The ground improvement device according to claim 1 of the present invention is provided with a discharge port for discharging the ground improvement material that is suspended in water and is supplied by a hose, and when the ground improvement device is pulled up from the state of being penetrated into the water bottom ground, the device itself The ground improvement device fills the space generated below along the locus with the ground improvement material discharged from the discharge port.

A ground improvement device according to a second aspect of the present invention is the ground improvement device according to the aspect of the first aspect, characterized in that the ground improvement device penetrates into the water bottom ground by its own weight.

A ground improvement device according to a third aspect of the present invention is the ground improvement device according to the aspect of the first or second aspect, which is provided with a convex portion on a lateral side.

The ground improvement device according to claim 4 of the present invention is characterized in that, in the aspect according to any one of claims 1 to 3, the ground improvement device is penetrated into the water bottom ground while discharging a penetration auxiliary material from the discharge port. It is a ground improvement device.

A ground improvement system according to claim 5 of the present invention is a ground improvement system comprising the ground improvement device according to any one of claims 1 to 4 and a positioning system for specifying a position of the ground improvement device. is there.

The ground improvement method according to claim 6 of the present invention comprises: a step of suspending a ground improvement device having a discharge port for discharging a ground improvement material supplied by a hose into water to penetrate into the water bottom ground; and a step of penetrating into the water bottom ground. The step of raising the ground improvement device described above, and filling the space generated below along the locus of the ground improvement device with the ground improvement material discharged from the discharge port.

A ground improvement method according to a seventh aspect of the present invention is the ground improvement method according to the sixth aspect, wherein in the step of intruding, the ground improvement device is dropped from a position higher than a surface of the water bottom ground by a predetermined distance. It is an improved method.

The ground improvement method according to claim 8 of the present invention is, in the aspect according to claim 6 or 7, a step of measuring a depth at which the ground improvement device penetrates into the water bottom ground in the step of penetrating; And a step of specifying the strength of the water bottom ground based on the depth measured in the step of performing the ground improvement method.

According to the invention of the present application, it is possible to improve the water bottom ground without requiring the configuration of pushing toward the water bottom ground and the configuration of stirring the water bottom ground.

Schematic which shows the whole structure of the ground improvement system 9. The figure which shows the structure of the ground improvement apparatus 1. The figure which showed the operation|movement which penetrates the ground improvement apparatus 1 in the water bottom ground 5. The figure which looked at water bottom ground 5 from which a plurality of improvement bodies 6 were formed from the upper part. The figure which shows the example of the shape of the weight 10 in a modification. The figure which shows the structure of the ground improvement apparatus 1d in a modification. The figure for demonstrating the water bottom ground 5 in which the some improvement body 6 was formed in the modification.

<Embodiment>
<Structure of ground improvement device>
FIG. 1 is a schematic diagram showing the overall configuration of the ground improvement system 9. The ground improvement system 9 shown in FIG. 1 includes a ground improvement device 1, a lifting device 2, a supply device 3, a sound wave transceiver 7, and a ship 8. The ship 8 is an example of construction equipment on the water or on land, and is, for example, a hoist ship. The ship 8 shown in FIG. 1 is a ship that floats on the surface of water 4 such as a river or the sea, and is equipped with an elevating device 2 and a supply device 3, and is equipped with an information processing device 81 that controls these.

The lifting device 2 includes a winch 21, a wire 22 that is wound up by the winch 21, and a crane 23 that suspends the wire 22. The tip of the wire 22 is connected to the upper surface of the ground improvement device 1.

The supply device 3 includes a pump 31, a hose 32, and a tank 33. The tank 33 is a container that stores the ground improvement material. The ground improvement material is a solidified material that can be pumped by pumping, represented by cement milk, mortar, grout, etc., and if the pumping distance becomes long at deep water, an admixture such as a retarder may be added. .. The tank 33 accommodates the ground improvement material manufactured by, for example, a ground improvement material manufacturing facility (not shown). The pump 31 sucks the ground improvement material stored in the tank 33 and supplies the ground improvement material to the ground improvement device 1.

The hose 32 is a pipe for supplying the ground improvement material to the ground improvement device 1. The hose 32 has one end attached to the discharge side of the pump 31 and the other end connected to the upper surface of the ground improvement device 1.

The ground improvement device 1 descends toward the water bottom ground 5 while being suspended in the water 4 (hereinafter also referred to as “underwater”) by the wire 22 of the lifting device 2. FIG. 2 is a diagram showing a configuration of the ground improvement device 1. FIG. 2A shows a perspective view of the ground improvement apparatus 1, and FIG. 2B shows a cross-sectional view of the ground improvement apparatus 1 in a plane along the vertical direction.

The ground improvement device 1 has a prismatic weight 10. The weight 10 has an upper surface suspended by a wire 22, and is used in a posture in which the long side is along the direction of gravity. Inside the weight 10, as shown in FIG. 2B, a cylindrical pipe 111 that forms a fluid flow path is provided in the vertical direction. The upper end of the pipe 111 is connected to the hose 32. The bottom face 101 of the weight 10 is provided with a discharge port 11 connected to the lower end of the pipe 111. The discharge port 11 is supplied by the hose 32 and discharges the ground improvement material that has passed through the pipe 111 toward the lower side of the ground improvement device 1. That is, the discharge port 11 is an example of a discharge port for discharging the ground improvement material supplied by the hose 32.

The ground improvement device 1 includes a sound wave transponder 16. The sound wave transponder 16 is a device that transmits a sound wave corresponding to the received sound wave.

The water bottom ground 5 is the ground existing below the water 4, and includes a soft layer 51 and a sand layer 52. The soft layer 51 is laminated on the sand layer 52. The soft layer 51 is an ultra-soft ground having an undrained shear strength of about 2 to 10 kPa. The sand layer 52 is a layer having a higher shear strength than the soft layer 51.

The sound wave transceiver 7 is installed on the surface of the soft layer 51. The sound wave transceiver 7 is a device that transmits a sound wave, receives the reflected wave, and measures the position of an object that reflects the sound wave.

In the ground improvement system 9, the position and orientation of the sound wave transceiver 7 are used as a reference for latitude, longitude, depth, and azimuth. The latitude, longitude, and depth of the sound wave transceiver 7 are specified, for example, by measuring a boring point at the time of installation by a Global Navigation Satellite System (GNSS) or the like. The posture of the sound wave transceiver 7 is specified by being adjusted at the time of installation, for example.

The sound wave transceiver 7 includes a wave transmitting unit that transmits sound waves such as ultrasonic waves into water, and a plurality of wave receiving units that receives sound waves transmitted into water. The plurality of wave receiving units has a configuration called a wave receiving array.

When the sound wave transceiver 7 sends a sound wave into the water, the sound wave transponder 16 of the ground improvement device 1 suspended in the water receives this sound wave and sends a corresponding sound wave.

The sound waves transmitted by the sound wave transponder 16 are received by the plurality of wave receiving units of the sound wave transceiver 7. The sound wave transceiver 7 is connected to the information processing device 81 by wire or wirelessly. When the sound wave transmitted from the sound wave transponder 16 is received, the sound wave transceiver 7 transmits a signal according to the received sound wave to the information processing device 81. Through this exchange, the sound wave transceiver 7 calls the sound wave transponder 16.

The information processing device 81 has a control unit, a storage unit, a connection unit, and the like. The control unit included in the information processing device 81 has a (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and the CPU stores computer programs stored in the ROM and the storage unit (hereinafter, The information processing device 81, the elevating device 2, and the supplying device 3 are controlled by reading out and executing a program (simply called a program) in the RAM.

Upon receiving the signal from the sound wave transceiver 7, the information processing device 81 identifies the time required for the sound wave to propagate between the sound wave transceiver 7 and the sound wave transponder 16 and the phase difference of the wave receiving unit from the signal. Then, the information processing device 81 calculates the distance from the sound wave transceiver 7 to the sound wave transponder 16 and the received wave angle based on the specified time and phase difference. As a result, the information processing device 81 identifies the position of the sound wave transponder 16, that is, the position information of the ground improvement device 1.

That is, the ground improvement system 9 includes a positioning system including the sound wave transceiver 7, the sound wave transponder 16, the information processing device 81, and the like, and the ground improvement device 1. The positioning system specifies the position of the ground improvement device 1. To do.

<Operation of ground improvement device>
FIG. 3 is a diagram showing an operation of penetrating the ground improvement device 1 into the water bottom ground 5.

As shown in FIG. 3A, the ground improvement device 1 has a wire 22 connected to the upper surface thereof and is suspended in water by the wire 22. Since the ground improvement device 1 has a larger specific gravity than the surrounding water 4, the winch 21 lowers the wire 22 to descend the water by its own weight.

As shown in FIG. 3( b ), when the ground improvement device 1 reaches the soft layer 51 of the water bottom ground 5, the bottom surface 101 of the ground improvement device 1 comes into contact with the surface of the water bottom ground 5 and receives a normal force from this surface. , The tension applied to the wire 22 changes. The operator on the ship 8 recognizes that the ground improvement device 1 has reached the bottom by observing the change in the tension, for example.

Since the soil improvement device 1 has a larger specific gravity than the soft layer 51, even after landing on the surface of the soft layer 51, it penetrates into the soft layer 51 by its own weight as shown in FIG. 3C. That is, the ground improvement device 1 penetrates into the water bottom ground 5 by its own weight. The soil 511 shown in FIG. 3C is soil or the like in the soft layer 51 that has been pushed away by the ground improvement device 1 that has penetrated.

As shown in FIG. 3D, the ground improvement device 1 further descends the soft layer 51 over a predetermined distance, and penetrates to the front of the sand layer 52 by its own weight. When the operator recognizes that the ground improvement device 1 has descended over a predetermined distance after landing on the soft layer 51, the operator operates the information processing device 81 to pull up the ground improvement device 1 with respect to the elevating device 2. Instruct. The winch 21 of the lifting device 2 winds up the wire 22 and pulls up the ground improvement device 1.

In addition, the information processing device 81 instructs the supply device 3 to supply the ground improvement material to the ground improvement device 1 according to the pulling speed of the ground improvement device 1. In response to the instruction, the supply device 3 drives the pump 31 and passes the hose 32 to the ground improving material stored in the tank 33 to the ground improving device 1 at a supply speed according to the pulling speed of the ground improving device 1. Supply. The ground improvement material supplied to the ground improvement device 1 is discharged downward from the discharge port 11.

As shown in FIG. 3E, a space S is formed below the ground improvement device 1 to be pulled up along the locus thereof. The volume of the space S may decrease due to the discharged soil 511 flowing in according to the pulling rate of the ground improvement device 1 or the hole wall of the soft layer 51 surrounding the space S collapsing. The information processing device 81 adjusts the pulling speed of the ground improvement device 1 and the supply speed of the ground improvement material to give an instruction. Thereby, the ground improvement device 1 fills the space S with the ground improvement material so that the volume of the space S does not decrease. It is desirable that this adjustment be performed so that the volume of the space S described above does not decrease at all, but if at least a part of the space S can be filled with the ground improvement material, the volume of the space S will decrease. May be.

That is, the ground improvement device 1 fills the space S generated downward along the locus of the device with the ground improvement material discharged from the discharge port 11 when the ground improvement device 1 is pulled up from the state of penetrating the water bottom ground 5. The ground improvement device 1 replaces the soft layer 51 that originally existed in the space S with the ground improvement material supplied from the supply device 3, and agitates the soil 511 and the ground improvement material that the device itself has pushed away. do not have to. In addition, when the builder who performs the soil improvement by the soil improvement device 1 adjusts the specific gravity of the soil improvement material in advance to the same level as that of the discharged soil 511, the effect of preventing collapse of the hole wall is also expected. it can.

When the ground improvement device 1 is pulled up and, for example, the bottom surface 101 thereof reaches the surface of the soft layer 51, the supply device 3 stops the supply of the ground improvement material. As a result, the space S generated below the ground improvement device 1 along the path of the ground improvement device 1 to be pulled up is filled with the ground improvement material discharged from the discharge port 11. The ground improvement material thus filled is solidified into the improved body 6 as shown in FIG.

FIG. 4 is a view of the water bottom ground 5 on which the plurality of improvement bodies 6 are formed, viewed from above. As shown in FIG. 4A, the plurality of improvement bodies 6 are formed on the water bottom ground 5 at substantially equal intervals.

The improved body 6 has a larger shear strength than the soft layer 51 of the water bottom ground 5. Therefore, in the water-bed ground 5 on which the plurality of improvement bodies 6 are formed, the supporting force, bending rigidity, shear rigidity, etc. are improved as compared with the original water-bed ground 5.

The ground improvement system 9 adjusts the size, the arrangement interval, etc. of the improvement body 6 according to the required improvement rate, that is, the improvement area per unit area. Further, the ground improvement system 9 may form a new improved body 6 by penetrating between the already formed plurality of improved bodies 6 by the ground improving apparatus 1 according to the required improvement rate. In this case, the ground improvement device 1 may penetrate into the soft layer 51 at a position overlapping the already formed improvement body 6, and as shown in FIG. 4B, two or more improvement bodies 6 are connected to each other. May be.

The operation of the soil improvement device 1 described above includes the steps of suspending the soil improvement device 1 equipped with the discharge port 11 for discharging the soil improvement material supplied by the hose 32 into water and allowing the soil improvement device 1 to penetrate into the water bottom soil 5, and the water bottom soil 5. The ground improvement method can be recognized as a ground improvement method including a step of pulling up the ground improvement apparatus 1 that has penetrated and filling the space S generated below along the trajectory of the ground improvement apparatus 1 with the ground improvement material discharged from the discharge port 11.

As described above, in the prior art, in order to push the device for improving the ground toward the submarine ground, it is necessary to have a configuration such as a cylindrical shell with an inverted bottom and an extendable clamp device (referred to as a "pushing mechanism"). .. Since the ground improvement device 1 according to the present invention penetrates the water bottom ground 5 by its own weight as described above, it is not necessary to provide the above-mentioned pushing mechanism.

Further, since the ground improvement device 1 according to the present invention does not mix the discharged soil 511 and the ground improvement material that the device itself has pushed away, it is not necessary to provide a structure for mixing the water bottom ground 5. That is, the ground improvement device 1 according to the present invention does not require a rotating mechanism or the like used in the configuration for stirring the water bottom ground 5.

<Modification>
The above is the description of the embodiment, but the contents of this embodiment can be modified as follows. Further, the following modified examples may be combined.

<Modification 1>
In the above-described embodiment, the ground improvement device 1 includes the prismatic weight 10, but the shape of the weight 10 included in the ground improvement device 1 is not limited to this. The ground improvement device 1 may have, for example, a cylindrical shape, a conical shape, or a spherical shape. FIG. 5: is a figure which shows the example of the shape of the weight 10 in a modification.

The weight 10a of the ground improvement apparatus 1a shown in FIG. 5(a) has a cylindrical shape, and the bottom surface 101a is provided with a discharge port 11a. The weight 10b of the ground improvement device 1b shown in FIG. 5(b) has a conical shape with its tip facing downward. The conical surface 101b of the weight 10b shown in FIG. 5B is directed downward, and the discharge port 11b is provided in the center. The weight 10c of the ground improvement device 1c shown in FIG. 5(c) is spherical. A discharge port 11c is provided in a part of the surface of the weight 10c facing downward.

When the ground improvement devices 1a, 1b, and 1c shown in FIG. 5 are also pulled up from the state of being penetrated into the water bottom ground 5, a space S is formed downward along the locus of the device itself. The ground improvement devices 1a, 1b, and 1c may fill the space S with ground improvement materials discharged from the discharge ports 11a, 11b, and 11c, respectively.

<Modification 2>
Instead of the embodiment described above, for example, a convex portion such as a blade or a protrusion may be provided on the side.

FIG. 6 is a diagram showing a configuration of a ground improvement device 1d in a modified example. FIG. 6A shows a perspective view of the ground improvement apparatus 1d, and FIG. 6B shows a cross-sectional view of the ground improvement apparatus 1d in a plane along the vertical direction.

The ground improvement device 1d shown in FIG. 6 includes a convex portion 12 on the side. As shown in FIG. 6( a ), the weight 10 of the ground improvement device 1 d is a square note, and the convex portions 12 extend on the bottom surface 101 side of the four side surfaces. The convex portion 12 shown in FIG. 6B is provided above the ejection port 11 in the gravity direction.

Also in the ground improvement device 1d shown in FIG. 6, when the ground improvement device 1d is pulled up from the state of penetrating the water bottom ground 5, a space S is formed below along the locus of the device itself. Since the ground improvement device 1d is provided with the convex portion 12 on the side, the space S is a space generated along the locus of the ground improvement device in which the weight 10 and the convex portion 12 are integrated. Therefore, by discharging the ground improvement material from the discharge port 11, the space S including not only the trajectory of the weight 10 but also the trajectory of the convex portion 12 is filled with the ground improvement material.

FIG. 7: is a figure for demonstrating the water bottom ground 5 in which the some improvement body 6a was formed in the modification. For comparison, FIG. 7A shows a view from above of the water bottom ground 5 when a plurality of improvement bodies 6 are formed by the ground improvement device 1 in which the convex portion 12 is not provided. On the other hand, FIG. 7B shows a view from above of the water bottom ground 5 when a plurality of improvement bodies 6a are formed by the ground improvement device 1d provided with the convex portion 12.

When the ground improvement device 1 is penetrated into the water bottom ground 5 a plurality of times, the plurality of improvement bodies 6 are formed in the range and distribution shown in FIG. 7A.

On the other hand, when the ground improvement device 1d is penetrated into the water bottom ground 5 multiple times at the same position as that shown in FIG. 7(a), the plurality of improved bodies 6a have the same range and distribution as shown in FIG. 7(b). Is formed by. The improvement rate of the water bottom ground 5 by the improvement body 6a shown in FIG. 7(b) is higher than that of the improvement body 6 shown in FIG. 7(a). This is because the improvement body 6a formed by the ground improvement device 1d has the portion 60a derived from the trajectory of the weight 10 and the portion 61a derived from the trajectory of the convex portion 12.

For example, when a heavy machine such as an excavator is installed and run on the improved water bottom ground 5, a force is applied in the horizontal direction, and a slip surface is likely to be generated inside the water bottom ground 5. As described above, the ground improvement device 1d is provided with the convex portion 12. Therefore, the improvement rate of the water bottom ground 5 by the formed improvement body 6a is higher than that in the case where the convex portion 12 is not provided. As a result, the bending rigidity and the moment of inertia of area of the submerged ground 5 as a whole are improved, a slip surface is less likely to occur, and the possibility that the submerged ground 5 collapses is suppressed.

<Modification 3>
In the above-described embodiment, the ground improvement device 1 penetrates into the water bottom ground 5 only by its own weight, but it may penetrate into the water bottom ground 5 while discharging the penetration auxiliary material from the discharge port 11. In this case, the supply device 3 may supply a penetration auxiliary material such as water or seawater when the ground improvement device 1 penetrates into the water bottom ground 5. The supplied penetration auxiliary material is discharged downward from the discharge port 11 and assists the penetration of the ground improvement device 1 into the water bottom ground 5 (soft layer 51). The discharge pressure of the penetration assisting material can be adjusted according to the hardness of the water bottom ground.

The penetration assisting material may be contained in a container other than the tank 33 and may be sucked by the pump 31 by switching the flow path on the suction side. Further, the penetration assisting material may be supplied by a pump other than the pump 31. Further, the penetration assisting material may be supplied by a hose 32 or a hose other than the hose 32.

The penetration assisting material may be any material as long as it can move in the hose and does not harden rapidly at the time of discharging and does not block the discharge port, but a fluid is preferable for efficiently pumping. The hose that supplies the ground improvement material uses water or seawater when cleaning the inside of the hose. Therefore, if the penetration auxiliary material is water or seawater, the hose to be supplied can be shared, which is more convenient.

Further, the penetration assisting material may be supplied to the ground improvement device 1 according to the speed at which the ground improvement device 1 penetrates into the water bottom ground 5. For example, the information processing device 81 monitors the penetration speed of the ground improvement device 1 based on the length of the unwound wire 22 and the position of the ground improvement device 1 specified by the positioning system. Then, when the monitored speed falls below the determined value, the information processing device 81 instructs the supply device 3 to supply the penetration auxiliary material to the ground improvement device 1 at a pressure according to the speed. do it.

<Modification 4>
In the above-described embodiment, the sound wave transceiver 7 measures its own latitude, longitude, and depth by GNSS or the like, but any of these may be measured or estimated by another configuration. For example, the sound wave transceiver 7 may include a water pressure gauge that measures water pressure. In this case, the depth of the position of the sound wave transceiver 7 is estimated from the water pressure measured by this water pressure gauge.

<Modification 5>
In the above-described embodiment, the sound wave transceiver 7 is installed on the surface of the soft layer 51, but may be installed on the bottom of the ship 8 or in the water under the ship 8. In this case, the sound wave transceiver 7 may be installed in water by, for example, being suspended by a wire or the like that is lowered from the ship 8 into water, or attached to the tip of a rod extended from the ship 8 into water.

The sound wave transceiver 7 may be installed in the ground improvement device 1. In this case, the sound wave transponder 16 may be installed on a wire, a rod, or the surface of the submarine ground 5 that is dropped from the ship 8 into the water.

Further, the sound wave transceiver 7 described above has a plurality of wave receiving portions, but a plurality of sound wave transceivers 7 arranged at different positions may each have a wave receiving portion.

Further, the sound wave transceiver 7 and the sound wave transponder 16 may include a so-called acoustic modem, an acoustic transducer, or the like. In this case, the sound wave transceiver 7 and the sound wave transponder 16 convert the information exchanged with each other using an acoustic transducer or the like into a sound wave and transmit it to the water, and when the sound wave is received, the above-mentioned information is extracted from this sound wave. do it.

Further, the positioning system is not limited to the configuration using sound waves. For example, one or more sensors may be arranged along the wire 22, and the information processing device 81 may specify the position of the ground improvement device 1 based on the information regarding the position detected by this sensor. As the sensor, for example, an angular velocity sensor such as an optical fiber gyro, an acceleration sensor such as a strain gauge type, a piezoelectric element type, or an electrostatic capacitance type is used.

The ground improvement system 9 penetrates the ground improvement device 1 into the modification target region of the water bottom ground 5 a plurality of times, and specifies the position of the ground improvement device 1 based on, for example, the sound wave transceiver 7 each time. As a result, the information processing device 81 stores the distribution of the penetration positions, that is, the distribution of the positions of the improvement bodies 6 formed by solidifying the ground improvement material. By referring to this distribution, the above-mentioned operator grasps which part of the reforming target area of the water bottom ground 5 is being reformed.

<Modification 6>
In the above-described embodiment, the weight 10 has the upper surface suspended by the wire 22 and is used in a posture in which the long side is along the direction of gravity, but the posture of the weight 10 is not limited to this. The weight 10 may be used in a posture in which the long side is along the horizontal direction. The posture of the ground improvement device 1 is substantially changed, for example, even if the bottom of the ground improvement device 1 bottoms on the soft layer 51 of the submerged ground 5 and a drag force is received from the surface of the soft layer 51, the change in the inclination falls within 10 degrees. It is desirable to be stable without doing so.

<Modification 7>
In the above-described embodiment, the ground improvement device 1 penetrates into the soft layer 51 by its own weight even after landing on the surface of the soft layer 51, but may be pulled up by a predetermined distance from the landed position. .. In this case, for example, when the operator described above recognizes that the ground improvement device 1 has reached the bottom, the operator operates the information processing device 81 to instruct the lifting device 2 to pull up the ground improvement device 1. The lifting/lowering device 2 winds up the wire 22 and pulls up the ground improvement device 1 to a position higher than the surface of the water bottom ground 5 by a predetermined distance. The operator may further operate the information processing device 81 to drop the ground improvement device 1 that has been pulled up and send to the elevating device 2 an instruction to penetrate the water bottom ground 5.

The ground improvement device 1 may be provided with a measuring unit that measures a resistance value when the ground improvement device 1 penetrates the water bottom ground 5 by dropping from a position higher by a predetermined distance h from the surface of the water bottom ground 5. .. This measuring unit is, for example, a spring type, a piezoelectric element type, a magnetostrictive type, an electrostatic capacitance type, a gyro type, a strain gauge type load cell, or the like. The measuring unit is attached, for example, inside the bottom surface 101 of the ground improvement device 1, and when the bottom surface 101 receives a vertical drag force from the surface of the water bottom ground 5, measures the resistance value due to the vertical drag force.

For example, as shown in FIG. 3( a ), the ground improvement device 1 is pulled up to a position higher than the surface of the water bottom ground 5 by a predetermined distance h, and then freely dropped to penetrate into the water bottom ground 5. At this time, the above-described measuring unit measures the resistance value received from the water bottom ground 5 and sends the measurement result to the information processing device 81. The information processing device 81 may specify the strength of the water bottom ground 5 based on the measurement result. The measurement unit may store the measured resistance value in the storage device. In this case, the resistance value stored in the storage device may be read by the information processing device 81 or the like when the ground improvement device 1 is collected on the water.

According to the ground improvement apparatus 1 of this modification, when the ground improvement apparatus 1 falls from a position higher than the surface of the water bottom ground 5 by a predetermined distance h, the resistance value when the ground improvement apparatus 1 penetrates into the water bottom ground 5 is measured. Therefore, the strength of the water bottom ground 5 is specified. The user of the ground improvement device 1 may select the ground improvement material to be supplied to the water bottom ground 5 or change the weight of the ground improvement device 1, for example, based on the specified strength.

The operation of the ground improvement device 1 according to this modification is performed in the process of suspending the ground improvement device 1 including the discharge port 11 that discharges the ground improvement material supplied by the hose 32 into the water and penetrating the water bottom ground 5. It can be recognized as a ground improvement method in which the ground improvement device 1 is dropped from a position higher than the surface of the water bottom ground 5 by a predetermined distance.

<Modification 8>
In the above-described embodiment or modified example 1, the operator did not measure the position of the surface of the water bottom ground 5 in the direction of gravity when recognizing that the ground improvement device 1 reached the bottom, but measured this. May be. According to the ground improvement device 1 of this modification, for example, the depth from the reference surface such as the water surface to the water bottom ground 5 is measured.

<Modification 9>
In the above-described modified example, the ground improvement device 1 includes the measuring unit that measures the resistance value when the ground material 5 drops and penetrates into the water bottom ground 5. However, the structure that measures the depth when penetrating into the water bottom ground 5 is provided. May have.

For example, as shown in FIG. 4D, when the operator drops the ground improvement device 1 from a position higher than the surface of the water bottom ground 5 by a predetermined distance h and penetrates into the water bottom ground 5, The depth d from the surface of the soft layer 51 of the water bottom soil 5 to the bottom surface 101 of the ground improvement device 1 that has penetrated may be measured based on the unwinding state of No.

In this case, the operator may specify the strength of the water bottom ground 5 based on the distance h and the measured depth d. The depth d may be estimated from the water pressure measured using a water pressure gauge.

The operation of the ground improvement device 1 according to this modification is performed in the process of suspending the ground improvement device 1 including the discharge port 11 that discharges the ground improvement material supplied by the hose 32 in water and allowing the ground improvement device 1 to penetrate into the water bottom ground 5. As a ground improvement method comprising a step of measuring the depth of penetration of the water bottom ground 5 by the improvement device 1 and a step of specifying the strength of the water bottom ground 5 based on the depth measured in the step of measuring the depth Can be recognized.

According to the ground improvement device 1 according to this modification, for example, the strength of the water bottom ground 5 is specified without measuring the resistance value when the ground improvement device 1 penetrates into the water bottom ground 5.

1... Ground improvement device, 1a... Ground improvement device, 1b... Ground improvement device, 1c... Ground improvement device, 1d... Ground improvement device, 10... Weight, 10a... Weight, 10b... Weight, 10c... Weight, 101...bottom surface, 101a...bottom surface, 101b...conical surface, 11...ejection port, 11a...ejection port, 11b...ejection port, 11c...ejection port, 111...pipe, 12...convex part, 16...sound transponder, 2...elevation Device, 21... Winch, 22... Wire, 23... Crane, 3... Feeding device, 31... Pump, 32... Hose, 33... Tank, 4... Water, 5... Water bottom ground, 51... Soft layer, 511... Soil discharge, 52... Sand layer, 6... Improved body, 6a... Improved body, 60a... Part, 61a... Part, 7... Sound wave transceiver, 8... Ship, 81... Information processing device, 9... Ground improvement system.

Claims (8)

Suspended in water,
Equipped with a discharge port for discharging the ground improvement material supplied by a hose,
A ground improvement device that fills a space generated downward along the locus of the device with the ground improvement material that is discharged from the discharge port when being pulled up from the state of penetrating the water bottom ground. The ground improvement device according to claim 1, wherein the ground improvement device penetrates into the subseabed by its own weight. The ground improvement device according to claim 1 or 2, further comprising a convex portion on a lateral side. The ground improvement device according to any one of claims 1 to 3, wherein the ground improvement device is penetrated into the water bottom ground while discharging a penetration auxiliary material from the discharge port. A ground improvement device according to any one of claims 1 to 4,
A positioning system for specifying the position of the ground improvement device,
Ground improvement system equipped with. A step of suspending the ground improvement device equipped with a discharge port for discharging the ground improvement material supplied by a hose into the water and allowing it to penetrate into the water bottom ground,
While pulling up the ground improvement device penetrating into the water bottom ground, filling the space generated below along the trajectory of the ground improvement device with the ground improvement material discharged from the discharge port,
A method for improving the ground. The ground improvement method according to claim 6, wherein, in the step of intruding, the ground improvement device is dropped from a position higher than a surface of the water bottom ground by a predetermined distance. In the step of intruding, the step of measuring the depth at which the ground improvement device has penetrated into the water bottom ground,
Based on the depth measured in the measuring step, a step of specifying the strength of the water bottom ground,
The ground improvement method according to claim 6 or 7, further comprising: