JP5681463B2 - Ground improvement equipment for underwater ground - Google Patents

Description

  The present invention relates to a ground improvement device for improving the bottom of a water bottom such as a river bottom, a lake bottom, or a sea bottom.

  The work to improve the soft ground to a ground with a predetermined strength is performed not only on land but also on the bottom of the water such as riverbed, lake bottom and seabed. For example, in order to build a bridge, a pier is necessary, but the foundation of the pier is constructed on the bottom of the river or the seabed. If this ground remains soft, the pier may fall over, so ground improvement is required.

  In addition, the coastal sea area is adjacent to factories, etc., and in addition to various pollutants flowing through the river, the sea bottom surface is covered with sludge layers such as sludge due to feed residues and excrement due to aquaculture, etc. It is necessary to improve the submarine mud layer to a healthy soil due to the progress of nutrition. This is because water pollution, generation of oxygen-free water mass, and eutrophication prevent the deterioration of productivity in the aquaculture industry, the occurrence of disease, malodor, and the decrease in transparency.

  Conventionally, the following apparatuses and methods have been proposed in order to improve such a submarine ground (for example, refer to Patent Documents 1 to 3).

  Patent Document 1 discloses an excavation and pumping device for a laminated seabed mud layer in which a sludge layer such as sludge is deposited on a surface layer and is formed of a sand layer or a soft layer. This equipment divides the laminated submarine mud layer into multiple levels in the height direction. First, the excavator is buried in the uppermost first layer, and the rotary blades and the screw blades of the vertical screw conveyor are driven to rotate. Then, while excavating the first layer from top to bottom, the excavated mud is pumped up by a vertical screw conveyor. The mud that has been pumped up is discharged from the discharge port, and sequentially falls and accumulates on the surface of the first layer discharged from the discharge pipe having the lower end above the surface of the first layer. When the first layer is completed, the second layer, the third layer,... Are continued in the same manner as described above, so that the first layer becomes the lowermost layer and completely reverses the stacking order before the operation. The ground is improved by changing the order of layering and converting the healthy layer with the least contamination to the surface layer.

  Patent Document 2 discloses a continuous wall forming groove excavating apparatus that enables excavation of the bottom of the water bottom. This drilling rig has a chain-type cutter that drills a groove for continuous wall construction on the seabed ground with a drilling blade, a drilling machine body installed on a trolley floating on the sea surface, and a chain-type cutter near the surface of the seabed ground. Supporting means for transmitting the reaction force excavated by the cutter to the main body of the excavator while supporting it, thereby enabling excavation of the ground at the bottom of the water, and from the solidified body supply device mounted on the base boat Cement milk is fed into the groove through the solidified material injection pipe to form a soil cement wall, thereby creating a continuous wall and improving the ground.

  Patent Document 3 discloses a ground improvement method for improving the ground of soft ground under water. In this method, a container-like structure, such as a caisson, is installed on the ground below the surface of the water, and the ground is improved by boring the area below the container-like structure on the ground below the surface of the water using a ground improvement device. Inserted the solidifying material injection means from the equipment, while rotating the solidifying material injection means, injecting the solidification material in the horizontal direction and raising the solidifying material injection means upward to improve the ground, occurred during the ground improvement Discharge, for example, slime, which is a mixture of soil and solidified material under the surface of the water, is accommodated in a container-like structure. As a result, the ground improvement can be performed on a stable scaffold without being affected by weather conditions, tide level, wave power, etc., and the fluid substances generated in large quantities during the ground improvement can be used effectively. Has been.

JP-A-8-218423 Japanese Patent Laid-Open No. 2003-3513 Japanese Patent Laid-Open No. 2004-197307

  In the conventional apparatus and method described above, by using a casing, a cover part, and a caisson, when the drilling is performed by a vertical screw conveyor in the casing, the work to be excavated and the discharge are accommodated in the cover part and the caisson. It can be diffused in water to prevent water pollution.

  However, in the apparatus described in Patent Document 1, since the first layer of mud is excavated by the excavating blade, not all flows into the opening, and the mud is not pumped by the vertical screw conveyor. There is a problem that it diffuses and causes turbidity.

  Moreover, in the apparatus and method described in Patent Document 2, each post or the like is sequentially extended while excavating the seabed ground from the excavator body with the excavation blade of a chain cutter, and when a predetermined depth is reached. After that, the cover part will cover the seabed ground, and after that, the cutter will circulate in the seabed ground, so even if normal scraping drilling is performed, mud and solidified materials will diffuse into the sea However, when excavating to a predetermined depth, mud is generated, and even after reaching a predetermined depth, diffusion cannot be prevented, causing turbidity. There's a problem.

  In the construction method described in Patent Document 3, a caisson is first installed, and waste such as mud and solidified material is accommodated in the caisson, so that the waste diffuses into the water outside the caisson and causes turbidity. The caisson that contains the discharge can be used as a base for artificial islands, revetments, piers, etc., but the caisson divided into multiple rooms is created and towed by a towing vessel. It is necessary to pour seawater into several rooms and set it in several rooms, and after all the empty rooms are filled with waste, the seawater must be discharged and emptied to fill the empty rooms. There is a problem that it takes time and costs for manufacturing and installing caisson. In addition, construction takes a long time, and only the ground below the installed caisson can be improved.

  In view of the above problems, the present invention is provided with a hollow member installed so as to extend from the ground of the bottom of the water to the surface of the water, and provided along the longitudinal direction adjacent to the outer surface of the hollow member, and the interior of the hollow member on the water surface An air injection pipe for injecting compressed air toward the surface, and a drilling device provided with a drilling member that is lowered to the bottom of the water bottom through the inside of the hollow member, excavates the ground, and injects the injection material to stir and mix with the soil. Adopt the configuration.

  In this configuration, a hollow member is installed, the excavation member is lowered through it, and the bottom of the bottom is excavated, so that the bottom of the bottom can be improved and the soil and injected material diffuse into the water. The compressed air is injected from the bottom of the water toward the water surface by the air injection pipe, so that the soil excavated and accommodated in the hollow member can be moved in the water surface direction and discharged. It is preferable that a plurality of air injection pipes are provided in the middle of the longitudinal direction so as to penetrate the wall surface of the hollow member and inject compressed air toward the water surface.

  The excavation member includes a hollow shaft body, a spiral blade provided around the shaft body, a protrusion provided so as to protrude from the outer periphery of the spiral blade, and the shaft body. And two or more injection pipes extending through the wall surface of the central portion and extending below the protruding portion along the lower surface of the spiral blade. The protruding portion is also provided on the tip of the shaft body and the lower surface of the spiral blade, and the protruding tip portion of the protruding portion is tapered toward the rotation direction during excavation, compared to the protruding portion. A chip manufactured by a material that is easily worn is attached.

  With this configuration, during excavation, high-pressure air can be supplied through the hollow shaft body and excavation can be performed while jetting the high-pressure air. By attaching a tip like this, the tip will wear even if it comes into contact with rocks etc., so that the protruding part will not be chipped, and further, the tip of the tip bites into the soil, and the scraped soil is moved up and down inside Since it can be smoothly fed between the existing blades, smooth excavation can be realized, a gap can be surely generated, and high-pressure air can be surely released.

  In addition, since the protruding portion to which such a tip is attached is also provided on the tip of the shaft body and the lower surface of the spiral blade, it can be smoothly excavated even if the number of rotations is increased, Since the compressed air can be surely released from the gap, the excavated soil can be smoothly fed rearward, and the excavation speed can be increased.

  The shaft body of this excavation member is formed so that the diameter is large at the central portion along the length direction and the diameter is small at both end portions, and the spiral blades are also directed from the both end portions to the central portion. Thus, the blade diameter is increased. The protrusions to which the above-mentioned tips are attached are arranged at equal intervals so that the straight line connecting the adjacent protruding tip or the tip of the protruding portion does not contact the outer periphery of the blade at least on the outer periphery of the blade having the maximum blade diameter. Provided. Otherwise, the outer periphery of the blade may come into contact with the hard hole wall of the hole made by excavation and may be damaged.

  In addition, the excavation member can include a plurality of plate-like protrusions disposed on the upper surface and the lower surface of the spiral blade. By this protrusion, the blades can rotate smoothly and can be effectively stirred. The protrusions sharply bite into the excavated soil sent by high-pressure air between the blades and smoothly feed the excavated soil backward, making it difficult to bite even if it contains stones or the like. The height of the protrusion is preferably as low as about 2 to 5 cm, and it is preferable that the tip is tapered so that it can be easily dropped downward from the top of the blade when there is a rolling stone.

  The excavator includes a hollow rod connected to a shaft body of an excavation member, a clamping unit that rotatably clamps and supports the rod, an arm that can change the angle of the rod, and an elevating unit that can raise and lower the rod. Compressed air supply means for supplying compressed air to be injected from the tip of the shaft body and injected from the air injection pipe through the inside of the rod and the shaft body, and injection material for supplying the injection material into the injection pipe Supply means.

  The ground improvement device can further include a suction discharge means for sucking and discharging the soil rising in the hollow member.

In addition, this apparatus injects the injection material from two or more injection pipes provided in the excavation member. As the injection material, a solidifying agent containing magnesium oxide (MgO) is injected as a slurry or dispersed in air. be able to. In addition to MgO, the solidifying agent can contain silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO), and ferric trioxide (Fe ₂ O ₃ ). Furthermore, diphosphorus pentoxide (P ₂ O ₅ ) can also be included. Since these solidifying agents are neutral, they do not cause the problem of alkaline soil, are inexpensive, and can obtain a ground having a higher strength than gypsum.

Rather than increasing the size of the excavating member, the injection material is injected at a pressure of 25-29 MPa at a supply rate of 0.28-0.33 m ³ per minute, to 2-8 times the maximum blade diameter It is possible to construct a cylindrical improvement body having a diameter of.

The figure which showed the structural example of the ground improvement apparatus of this invention. Sectional drawing which showed the place which inserted the excavation member in the hollow member. The figure which illustrated the excavation member used for a ground improvement apparatus. The figure which illustrated arrangement | positioning of the protrusion part provided in the outer periphery of a helical blade | wing, and a chip | tip. The figure which expanded and showed the protrusion part and tip which an excavation member is provided. The figure which illustrated the excavation member provided with protrusion. The figure which showed another structural example of the ground improvement apparatus of this invention.

  FIG. 1 is a diagram showing a configuration example of a ground improvement device for water bottom ground according to the present invention. This ground improvement device is used in rivers, lakes, seas, and the like, and is a device that purifies soil in the bottom of the river bottom, lake bottom, sea bottom, etc., and performs ground improvement to improve the ground strength. In general, the surface of the water bottom 1 is covered with a sand layer, and soil exists below it. This device is provided so as to extend from the water bottom 1 to the water surface 2 and adjacent to the outer surface of the hollow member 10 along the longitudinal direction of the hollow member 10. Excavation provided with an air injection pipe 11 for injecting compressed air toward the surface, and an excavating member 12 that is lowered to the ground of the bottom 1 through the inside of the hollow member 10 and excavates the ground and injects the injected material to mix with the soil. And a device.

  In this apparatus, first, the hollow member 10 is set up vertically with respect to the water surface, and its tip is installed so as to be buried in a sand layer covering the surface of the water bottom 1, and the water in the hollow member 10 is sucked by suction means such as a pump. And pull out. For example, it can be installed so as to be buried about 1 m. Thus, by installing so that the front-end | tip part of the hollow member 10 may be buried in a sand layer, it can prevent reliably that a waste mud flows out from between the hollow member 10 and the ground of the water bottom 1, and generates turbidity. it can.

  Next, the excavation member 12 is lowered through the hollow member 10 and the excavation member 12 is rotated in a certain direction, thereby excavating the ground of the bottom 1. Since the ground is excavated in this way, the soil and the injection material injected thereafter are not diffused into the water. Further, when excavated, the excavation member 12 is buried in the ground, and the excavated soil for the volume removed by the excavation member 12 is accommodated in the hollow member 10 as at least waste mud, so that the air injection pipe 11 is moved from the bottom 1 to the water surface 2 by the compressed air injected from the water 11, and the discharged mud moved to the vicinity of the water surface 2 is discharged by a sand pump 13 as a suction discharge means.

  The discharged mud is put into the mud tank 14, and the soil particles in the mud are naturally settled and separated into a supernatant and a solid content. Thereafter, the supernatant liquid is collected, subjected to water treatment as necessary, and then returned to a river, a lake, the sea, or the like.

  The hollow member 10 is a hollow cylindrical tube and is made of carbon steel, stainless steel, concrete, ceramic, or the like so as to have a strength that does not deform due to water pressure, waves, or the like. The air injection tube 11 is manufactured from a plastic such as hard polyvinyl chloride or FRP (fiber reinforced plastic) in addition to the same material, and has a shape whose tip is folded back into, for example, a U shape or a V shape. For this reason, when it adjoins the side wall of the hollow member 10 and it is arrange | positioned toward the water bottom 1 along the longitudinal direction, a front-end | tip will face the water surface 2. FIG.

  When the hollow member 10 and the air injection pipe 11 are arranged, the excavation member 12 is inserted into the hollow member 10 and the lowering portion is shown, the cross section shown in FIG. 2 is obtained. In FIG. 2, two air injection pipes 11 are provided adjacent to the side wall of the hollow member 10 (for example, a diameter of 1.4 m), and a drilling member 12 (for example, a maximum blade diameter of 1 m) is provided inside the hollow member 10. Is inserted and lowered toward the ground of the bottom 1. A plurality of air injection pipes 11 are preferably provided in order to push up and discharge the waste mud upward. If two air injection pipes 11 are provided, the air injection pipes 11 are arranged at positions facing each other so as to sandwich the hollow member 10 as shown in FIG. It is preferable to be provided. Further, as shown in FIG. 1, a plurality of air injection pipes 11 are preferably provided in the middle of the longitudinal direction so as to penetrate the wall surface of the hollow member 10 and inject compressed air toward the water surface. .

  As shown in FIG. 3, the excavation member 12 includes a hollow shaft body 20, a spiral blade 21 provided around the shaft body 20, and a protrusion 22 provided so as to protrude from the outer periphery of the spiral blade 21. Two or more injection pipes 23 and 24 that pass through the inside of the shaft body 20, pass through the wall surface of the central portion of the shaft body 20, and extend below the protruding portion 22 along the lower surface of the spiral blade 21. The protruding portion 22 is also provided on the tip of the shaft body 20 and the lower surface of the spiral blade 21, and the protruding portion 22 has a shape tapered toward the rotating direction at the time of excavation at the protruding tip portion of the protruding portion 22. A tip 25 made of a material that is more easily worn than the tip 25 is attached.

  The excavation member 12 is connected to a hollow rod 26 that is rotatably held by a heavy machine (not shown), and the inside of the rod 26 and the inside of the shaft body 20 are in communication with each other. For this reason, compressed air can be supplied through the inside of the rod 26 and the inside of the shaft body 20, and can be injected from the front-end | tip of the shaft body 20 at the time of excavation. The excavation of the ground of the bottom 1 is started by rotating the rod 26 at a constant speed in a constant direction, rotating the excavating member 12 at the same speed in the same direction, and lowering the rod 26 at a constant speed.

  Since the tip 25 is attached to the tip of the shaft body 20 of the excavation member 12 and the lower surface of the spiral blade 21, the tip 25 scrapes the ground and excavation is performed. The excavated soil is fed backward between the blades of the spiral blade 21 in the direction opposite to the rotation direction. In this excavation member 12, the excavation soil is only sent backward, and after passing between the blades, the excavation member 12 stays on the spot so that it is not discharged as waste mud.

  Since the ground includes hard rocks, stones, etc., the chip 25 comes into contact with these rocks and stones and tries to scrape them, but since it is made of a relatively soft material, it will not chip and wear. Excavation is carried out.

  In order to perform excavation efficiently, excavation is performed while jetting compressed air from the tip of the shaft body 20. Compressed air pushes the excavated soil between the blades of the spiral blade 21 and smoothly sends it to the rear, reduces the impact on the ground during excavation, and gives the excavating member 12 a rocking stirring effect to facilitate excavation. At the same time, heat generation of the tip 25 provided at the tip of the shaft body 20 is suppressed. The compressed air can be supplied at a pressure of 0.5 to 2 MPa, for example.

  The above-mentioned effect can be obtained by injecting compressed air. However, if the inside of the excavation hole is covered with the spiral blades 21, there is no escape route for the injected compressed air, and further excavation can be performed. In some cases, the excavation member 12 may become slanted, and a heavy machine (not shown) connected thereto may roll over. However, in the present invention, the protrusion 22 and the tip 25 are provided on the outer periphery of the spiral blade 21, thereby forming an appropriate gap around the spiral blade 21, and compressed air injected from the gap is formed. Such a problem does not occur.

  In addition, by providing the protrusion 22 and the tip 25 in this way, forming an appropriate gap, and allowing the compressed air that has been reliably injected to escape upward, excavate smoothly even if the rotational speed is increased. Can be performed and the excavation speed can be increased. In addition, since the tip 25 is provided not only on the tip of the shaft body 20 but also on the lower surface of the spiral blade 21, it is possible to perform excavation at a high speed even on a more efficient and hard ground, and the construction in a short period of time. Can be realized.

  When excavating to a predetermined depth, the rotation of the rod 26 is switched in the opposite direction. Then, the rotation direction of the excavation member 12 is also reversed, so that the excavation soil that has been sent rearward and is located above the excavation member 12 passes between the blades of the spiral blade 21 and is sent into the excavation hole below the excavation member 12. become. At the same time, the injection of the injection material is started from the two injection pipes 23 and 24 included in the excavation member 12 while the rod 26 is raised at a constant speed.

  The injection material is injected by a constant amount at a constant pressure, and is mixed with the surrounding soil by the rotation of the spiral blade 21, the protrusion 22 and the tip 25. By performing this up to the vicinity of the bottom 1 and constructing a cylindrical improvement body in the ground, the bottom bottom is improved.

  The shaft body 20 can have a constant overall length of 0.8 to 1 m, a central portion of 0.16 to 0.2 m, and a central portion having a diameter of 0.4 m, for example. For example, the length of one end and the other end of each end can be increased to a diameter of 0.14 m to 0.4 m at a constant rate within a range of 0.32 m. When the overall length is 0.8 m, the center length is 0.16 m, and the lengths of both ends are each 0.32 m, the taper angle that expands at a constant rate is about 22 °. At this time, the maximum blade diameter of the spiral blade 21 can be about 1 to 2.5 m. Incidentally, the blade diameter is a diameter from one end of the blade to the other end through the shaft body 20. The diameter of the hollow member 10 can be determined according to the maximum blade diameter, or the maximum blade diameter can be determined according to the diameter of the hollow member 10.

  The protruding portion 22 can be a substantially rectangular plate having a length in the protruding direction of about 0.1 m, and the tip 25 is attached to the protruding tip by welding or the like. A plurality of the protrusions 22 are attached as shown in FIG. 4 so that the straight line connecting the adjacent protrusions 22 does not contact the outer periphery of the spiral blade 21. This is determined in consideration of the protruding length of the protruding portion 22 and the diameter of the spiral blade 21, and an appropriate number is provided. If the number is too small, excavation becomes difficult. If the number is too large, inconveniences such as a small gap for the compressed air to escape occur.

  In FIG. 4, six protrusions 22 and tips 25 are provided on the outer periphery of the spiral blade 21. Thus, by providing the minimum protrusion 22 and the tip 25 so that the straight line connecting the adjacent protrusions 22 does not contact the outer periphery 27 of the spiral blade 21, a sufficient gap is generated, and during excavation The compressed air jetted in can be discharged into the atmosphere through the gap. Further, the high-pressure air injected from the tip of the shaft body 20 can provide a lubricant effect, and the high-pressure air can be discharged so as not to exceed the weight of the apparatus.

  The shaft body 20 and the spiral blade 21 may be made of any material as long as it has a strength that can be inserted into the soil. For example, carbon steel, stainless steel, or a superalloy can be used. Examples of the superalloy include titanium, zirconium, hafconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, thorium and other carbides, nitrides, borides, silicide powders, iron as a metal binder, A material sintered at a high temperature of 1300 ° C. to 1600 ° C. in an inert gas such as hydrogen or nitrogen can be used together with either cobalt or nickel. The protrusion 22 is made of tungsten carbide (WC) and cobalt (Co) represented by E1 to E4 of JIS classification symbols having a Rockwell hardness (HRA) measured by a Rockwell test of JIS G0202 of 87.5 or more. It can manufacture with the cemented carbide containing.

  On the other hand, the chip 25 can be manufactured from a WC-Co based cemented carbide of HRA86.5 or higher represented by E5 of the JIS classification symbol, which is softer than the cemented carbide used for the protruding portion 22, and gradually. By wearing it, it is possible to prevent chipping even when it comes into contact with hard ground or rocks and to facilitate excavation.

  By using such a soft material, even if the cobblestone is kicked and excavated, the tip 25 does not fly, and even when excavating toward the rock, it gradually decreases from the tip of the tip 25. You can drill until 25 runs out.

  As shown in FIG. 5A, the tip 25 is attached to the tip of the protruding portion 22 in the protruding direction by welding or the like. If the tip 25 is detached, the protruding portion 22 itself is hard ground, rock, or the like. Therefore, it is desirable to build up and reinforce the joint portion 28.

  As shown in FIG. 5A, the tip 25 is tapered toward the rotation direction of the excavation member 12 (here, the direction indicated by the arrow A), and the tip 25 protrudes from the protruding end of the protruding portion 22. It joins and the joining part 28 is piled up.

  When viewed from the direction of the arrow X in FIG. 5 (a), the shape is substantially rectangular, as shown in FIG. 5 (b), and the tip of the excavating member 12 facing the rotational direction has an arc shape. Yes. Then, the raised joint portion 28 is raised. This shape is the same when viewed from the direction of arrow Y in FIG.

  As shown in FIGS. 5A and 5B, the protrusion 22 includes a substantially rectangular upper surface 30 joined to the outer periphery and the lower surface of the spiral blade 21, and an inclined surface 31 continuous with a predetermined inclination angle thereto. , 32, a curved surface 33 that connects the inclined surface 31 and the inclined surface 32 in an arc shape, and a side surface that is continuous with the curved surface 33.

  The tip 25 is attached to the inclined surface 31 side of the tip portion where the inclined surface 31 and the curved surface 33 are continuous, and the joint portion 28 between the tip 25 and the protruding portion 22 is built up.

For example, the width W ₀ of the protrusion 22 is 32 mm, the width W ₁ of the chip 25 is 30 mm, the depth L of the protrusion 22 including the chip 25 is 63 mm, and the inclination angle θ of the curved surface 33 with respect to the horizontal direction is 5 °. can do. In this way, the inclination angle is set at about 2 ° to 10 °, and the tip 25 is not oriented in parallel with the outer periphery of the spiral blade 21 but slightly outside, thereby taking in more soil. The diameter of the excavation hole can be increased, and a sufficient gap can be generated to facilitate excavation.

  As shown in FIGS. 5A and 5B, the protrusion 22 to which the chip 25 is attached is shaped like a human finger, has a certain width, and has a tapered shape. 25 bites into the soil, scoops up like a shovel, is taken in between the upper and lower blades along the inclined surface 31, and is sent back between the blades to scrape the soil and excavate the soil smoothly. be able to. Moreover, if it sends back along this inclined surface 31, a clearance gap will arise in the inclined surface 32 side, and when this expands, the escape path of sufficient compressed air can be formed.

  Referring again to FIG. 3, the two injection pipes 23 and 24 are inserted into the shaft body 20 of the excavation member 12, penetrate the central wall surface of the shaft body 20, and have the maximum diameter of the spiral blade 21. It extends along the lower side of the blade. These injection tubes 23 and 24 are inserted inside the shaft body 20, extend through the wall of the central portion of the shaft body 20 to the lower side of the projecting portion 22 along the lower surface of the spiral blade 21, and A soil purification agent for purifying soil, a solidifying agent added to form a ground with a predetermined strength, and the like can be injected as an injection material in a state of being dispersed in slurry or gas and mixed with soil.

  Since the injection pipes 23 and 24 extend in the horizontal direction along the lower side of the blade having the maximum diameter of the spiral blade 21, the length extending in the horizontal direction can be made relatively long. It can be accelerated and injected farther. For example, when the maximum blade diameter is about 2.5 m, the length is about 0.7 m. By adopting a pipe with a smaller diameter in the horizontal direction in the extending direction, the injection force can be further increased, and the injection can be performed farther.

  It is preferable that a plurality of these injection pipes 23 and 24 are provided in order to inject injection materials such as the above-mentioned purifying agents and solidifying agents in all directions and to sufficiently mix with surrounding soil to construct an improved body. For example, two or three injection tubes 23 and 24 can be provided. When three are provided, as shown in FIG. 4, the angle formed by the adjacent injection tubes can be 120 °. It is possible to provide four or more, but since it will be injected from the next adjacent injection tube immediately after being injected from one injection tube, it is a location very close to the point where it was injected once The injection material is wasted. For this reason, in order to inject efficiently in a wider range with a small injection amount, the above two or three are desirable.

  In addition, the injection pipes 23 and 24 can be simply steel pipes having a predetermined diameter, but a spiral plate that can supply and inject a slurry or gas in a spiral manner is provided therein, and is coiled. Instead of spraying slurry and gas only in a certain direction, it is possible to spray and spread slurry and gas widely in the top, bottom, left and right, effectively stirring and mixing in small amounts, and improving the ground It is.

  The tips of the injection pipes 23 and 24 are arranged below the protrusion 22 and the tip 25, and the tip is also extended to the outer periphery of the spiral blade 21, so that the injection material is from the protrusion 22 and the tip 25. It is not injected upward.

  A cylindrical improvement body is constructed by pulling up the excavation member 12 while injecting the injection material. The improved body to be constructed is preferably larger in diameter because the construction period becomes shorter. However, when the length of the shaft body 20 of the excavation member 12 is increased and the diameter of the spiral blade 21 is increased, the heavy machinery that supports the excavation member that has been used so far can support the enlarged excavation member. Without falling. For this reason, it is necessary to enlarge the heavy equipment to be supported and to increase its weight. This is costly and cannot be easily moved, so that the performance deteriorates. Therefore, the injection pressure of the injection material is increased, and the injection amount is increased to construct a large improved body.

  When the improved material is constructed by injecting the injection material, the excavating member 12 is rotated in the direction opposite to that during excavation. At this time, the loose excavated soil is placed on the spiral blade 21 of the excavating member 12. In order to prevent mud from being generated, when the excavating member 12 is pulled up while injecting the injection material, the excavated soil placed on the excavating member 12 is taken into the excavation hole below the excavating member 12. We have to go. In order to take in the excavated soil, it is conceivable to increase the rotation speed, and in the conventional excavation member described above, excavation on the spiral blade 21 is performed unless the rotation speed is 22 to 26 rotations / minute. The soil no longer slides down and mud is generated.

  On the other hand, when the excavating member 12 employed in the present invention is used, since the projecting portion 22 and the tip 25 are provided, an appropriate gap is formed at the time of excavation, and the excavated soil that has been put up is taken in through the gap. Therefore, the excavation member 12 can be smoothly taken in without increasing the rotational speed. For this reason, it is possible to smoothly perform the stirring and mixing of the injected material without securing the number of rotations as much as 20 to 22 rotations / minute. Thereby, it becomes possible to perform construction safely.

  As the rotational speed is increased, the excavated soil is excessively taken into the excavation hole, and the front of the apparatus for supporting the excavation member 12 is in a floating state. In addition, the hose connected to the injection pipes 23 and 24 may be entangled with the rod 26 and may roll over. However, by adopting the configuration in which the tip 25 is provided in the protruding portion 22 as in the present invention, the soil can be improved stably at a rotational speed of 20 to 22 revolutions / minute.

  When a large amount of injection material is injected at a high pressure, it can be spread over a wide range of soil, but when the lifting speed of the excavating member 12 is constant and the rotation speed is high, the number of injections at the same position increases. The hole wall tends to collapse. For this reason, the pressure cannot be increased so much, and the injection amount is limited.

However, if the excavation member 12 employed in the present invention is used, it is not necessary to increase the rotational speed from 20 to 22 revolutions / minute to 22 to 26 revolutions / minute as described above. The amount can also be increased. In the present invention, for example, the injection material can be injected at a pressure of 25 to 29 MPa at 0.28 to 0.33 m ³ / min. In the case of injection with three injection tubes, the injection can be performed at a rate of about 0.09 to 0.11 m ³ / min from one injection tube.

  In the present invention, there is a boulder from the surrounding soil at the top of the spiral blade 21, and if the boulder is taken in, there may be a problem in excavation. However, if the excavated soil between the blades is clogged and cannot be sent backward, mud is generated. For this reason, as shown in FIG. 6, a protrusion 29 is provided on the upper surface of the spiral blade 21, but if the protrusion length of the protrusion 29 from the blade surface is long, the rolled stone does not fall into the hole, It stays on the spiral blade 21, which causes clogging.

  For this reason, while the protrusion length of the protrusion 29 from the blade surface is shortened to about 2 to 5 cm and a taper is formed, Can be configured to fall. Therefore, the protrusion 29 is manufactured from the same material as the shaft body 20, the spiral blade 21, and the protrusion 22, and can be a trapezoidal plate-like object.

  The ground improvement device of the present invention can change the angle of the rod 26 and the hollow rod 26 for connecting the excavating member 20 as well as the clamping means 40 for rotatably holding and supporting the rod 26 as shown in FIG. Arm 41 to be moved up and down, lifting means 42 to be able to move up and down rod 26, compressed air for supplying compressed air to be injected from the tip of shaft body 20 through hollow rod 26 and shaft body 20 It further includes supply means 43 and injection material supply means 44 for supplying the injection material into the injection pipes 23 and 24. The clamping means 40, the arm 41, and the lifting / lowering means 42 constitute a heavy machine including an operation room that is operated by an operator. The compressed air supply means 43, the injection material supply means 44, the sand pump 13 and the mud tank 14 Are installed on a trolley 45 floating on the water surface 2.

  When ground improvement is performed using this ground improvement device, the base boat 45 is operated to move the base boat 45 to a position where the ground improvement is to be performed. After that, the hollow member 10 is installed, the excavating member 12 is lowered, rotated to perform excavation, and the ground is improved by injecting the injected material while raising the reverse rotating to raise the excavation member 12. When excavation is performed, the angle of the rod 26 is adjusted by the arm 41 so that the rod 26 becomes perpendicular to the water surface, and then the rotation of the rod 26 is started by the clamping means 40 to move the excavation member 12 in one direction. And the rod 26 is lowered to the ground of the bottom 1 by the elevating means 42, so that the excavation member 12 can penetrate into the ground and the soil can be excavated to a predetermined depth.

  When the excavating member 12 penetrates into the ground by the lowering of the rod 26, the compressed air is supplied from the compressed air supply means 43 through the rod 26 and the inside of the shaft body 20, and the compressed air is also supplied to the air injection pipe 11. . And it is made to inject from the front-end | tip of the shaft body 20, and the air injection pipe 11.

  After excavating to a predetermined depth, the direction of rotation of the excavating member 12 is reversed, and the injection material supply means 44 is activated while the rod 26 is raised by the elevating means 42, and the injection material is injected from the injection pipes 23 and 24. The injection material accelerates in the injection pipes 23 and 24 extending in the horizontal direction along the blade surface, and is injected toward the soil around the excavation member 12 to penetrate into the soil. Since the spiral blade 21 rotates, the injection material is sufficiently stirred and mixed with the soil and is uniformly dispersed in the soil.

  At this time, since the excavated soil on the spiral blade 21 is taken into the excavation hole below the excavation member 12 through the gap formed by the protrusion 22 and the tip 25, the excavation member can be stably and excavated. At a lower speed of 12, a higher pressure and a larger amount of injection material can be injected. The excavating member 12 is lifted after stopping the injection of the injection material near the water surface. In this way, a cylindrical improvement body is formed in the water bottom ground. By forming this improved body so as to overlap, it is possible to purify the ground in a predetermined region of the bottom of the water and improve the ground to have a predetermined strength.

  The following materials can be used as the injection material that can be used in the ground improvement device. Conventionally, when purifying soil contaminated with an organic chlorine compound, an oxidizing agent, iron powder, iron oxide powder or the like has been used. In addition to this, cement milk, lime, gypsum and the like have been used as a solidifying material in order to fix heavy metals and obtain a ground having a predetermined strength.

  Although cement milk and lime can obtain a strong ground, they exhibit a strong alkalinity, which causes a problem of alkaline soil. On the other hand, since gypsum shows neutrality, the problem of alkaline soil does not occur, but a certain strength cannot be obtained.

Therefore, a neutral solidifying agent that can obtain a higher earth strength than that of the gypsum-based solidified material and is provided at a low cost is employed to solve these problems. In the present invention, as the neutral solidifying agent, a solidifying agent containing calcium oxide, sulfur trioxide and silicon dioxide as main components and additionally containing aluminum oxide, ferric trioxide and magnesium oxide can be used. This solidifying agent has a bulk density of 1.2 to 1.3, a specific surface area of about 4 cm ² / g, and calcium oxide, sulfur trioxide, and silicon dioxide of about 40 to 45% and about 25 to 30%, respectively. About 15-20%.

The solidifying agent has a high dewatering function, lime aluminum reacts with the calcium sulfate, to produce a _{3CaO · Al 2 O 3 · 3CaSO} 4 · 32H 2 O having a mineral composition. Thus, since this compound contains a large amount of water, this solidifying agent can be combined and fixed with a large amount of water in the course of the hydration reaction. Moreover, since the excessive sulfurized aluminate and aluminum ions neutralize and stabilize the pH, the soil can be maintained neutral for a long period of time.

A magnesium oxide-based solidifying agent can also be used. This solidifying agent containing magnesium oxide as a main component is a low pH solidifying agent and is characterized by a small load on the environment.
Solidification by the solidifying agent is performed by the progress of carbonation of MgO between the particles of the solidification target and the growth of MgCO ₃ .3H ₂ O crystals.

This solidifying agent fixes and insolubilizes fluorine and boron contained in the soil. Specifically, the surface of MgO is hydrated to become Mg (OH) ₂ , the OH group on the surface becomes OH ₂ ⁺ and becomes positively charged, and F ⁻ and H ₂ BO ₃ ⁻ are formed by electrostatic attraction. It is insolubilized by adsorption.

By adding fine minerals such as molten phosphorus, serpentine, olivine, montmorillonite, halloysite, gibbsite, and allophane together with this solidifying agent, heavy metals can be insolubilized and soil purification can be realized. Here,熔phosphorus, MgO: 16 _{wt%, Al} 2 O 3: 1.9 wt%, _SiO 2: 28 _{wt%, P 2} O 5: 19 wt%, CaO: 31 wt%, _Fe 2 _{O 3} : 3.2 wt%, serpentinite, MgO: 44 _{wt%, Al} 2 O 3: 1.6 wt%, _SiO 2: 47 wt%, CaO: 1.6 _wt%, Fe _{2 O} 3: 5 The olivine is MgO: 45% by mass, Al ₂ O ₃ : 1.2% by mass, SiO ₂ : 47% by mass, CaO: 1.0% by mass, Fe ₂ O ₃ : 5.5. % By mass. Montmorillonite is a crystalline clay mineral represented by the chemical formula Na _0.67 Si ₈ (Al _3.33 Mg _0.67 ) O ₂₀ (OH) ₄ .nH ₂ O, and halloysite is a crystalline clay mineral. And the chemical formula Si ₂ Al ₂ O ₅ (OH) ₄ · 2H ₂ O, gibbsite is a hydroxide, the chemical formula Al (OH) ₃ , allophane is an amorphous mineral, ~ 2) SiO ₂ · Al ₂ O ₃ · (2.5 to 3) H ₂ O.

For example, when Pb is insolubilized by adding the above-described molten phosphorus, calcium and magnesium contained in the dissolved phosphorus are eluted as Ca ²⁺ and Mg ²⁺ in the solution, and the solution exhibits weak alkalinity. For this reason, OH ⁻ is present in the solution, which reacts with Pb to produce poorly soluble Pb (OH) ₂ . This Pb (OH) ₂ adheres to the surface of the mineral particles and is insolubilized.

  Similarly, heavy metals such as cadmium, hexavalent chromium, arsenic, mercury, and selenium, the above fluorine, boron, hydrogen ions, and the like can be insolubilized below the soil environment standard.

Layered silicate clay minerals such as montmorillonite replace exchangeable cations such as Ca ²⁺ to charge the layers negatively and adsorb cations over a wide pH range. Amorphous aluminosilicate minerals such as allophane adsorb anions because the surface charge is positive when the solution is acidic, and the surface charge is negative when the solution is alkaline. Adsorbs cations. Similarly, hydroxides and iron oxides such as gibbsite have a negative surface charge when the pH of the solution is high, adsorb cations, and a positive surface charge when the pH of the solution is low. Adsorbs anions.

  These solidifying agents can be added with minerals as necessary, dispersed in water, air, etc., supplied to the ground improvement device of the present invention as slurry or gas, and injected into the ground to improve the ground. it can.

Using this slurry and gas containing a solidifying agent that can obtain a desired strength at a low cost as an injection material, this injection material is injected at a high pressure of 25 to 29 MPa, and about 0.3 m ³ / min. By making the injection amount much larger than the injection amount, it can be constructed at low cost, and even with the excavation member 12 of the same size, a larger improved body can be constructed in one operation, The number of improved bodies can be reduced and the construction period can be shortened.

In the above description, the maximum diameter of the spiral blade 21 is described as 1 to 2.5 m. However, the maximum diameter is not limited thereto, and for example, a diameter of 0.35 m to 3 m can be used. When the above-mentioned pressure of 25 to 29 MPa is injected at 0.28 to 0.33 m ³ / min, when the improved blade is constructed using the spiral blade 21 having a maximum blade diameter of 0.35 m, A cylindrical improvement body with a diameter of 2.35 m can be constructed.

  By the way, 2.5 m for a diameter of 0.5 m, 2.7 m for a diameter of 0.7 m, 4.7 m for a diameter of 1.2 m, 5 m for a diameter of 1.5 m, 5.5 m for a diameter of 2 m, 6 m for a diameter of 2.5 m, With a diameter of 2.8 m, it is possible to construct a 6.3 m cylindrical improvement body, and from this, with this pressure and injection volume, an improvement body having a diameter 2 to 8 times the maximum blade diameter is constructed. be able to.

The injection pressure and the injection amount are merely examples, and are not limited to these values. Therefore, the pressure may be 29 MPa or more, and the injection amount may be 0.33 m ³ / min or more.

  Also, in order to convert the soil contaminated by sludge etc. into healthy soil, the bottom of the ground mixes microorganisms such as bacteria, active bacteria, photosynthetic bacteria, yeasts, lactic acid bacteria, and koji molds into the injection material and injects it It is also possible to purify the soil.

  So far, the ground improvement device of the present invention has been described in detail with reference to the embodiments shown in the drawings, but the present invention is not limited to the above-described embodiments, and other embodiments, additions, Modifications, deletions, and the like can be made within the scope that can be conceived by those skilled in the art, and any aspect is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

DESCRIPTION OF SYMBOLS 1 ... Water bottom, 2 ... Water surface, 10 ... Hollow member, 11 ... Air injection pipe, 12 ... Excavation member, 13 ... Sand pump, 14 ... Sludge tank, 20 ... Shaft body, 21 ... Spiral blade, 22 ... Protrusion part , 23, 24 ... injection tube, 25 ... tip, 26 ... rod, 27 ... outer periphery, 28 ... joint portion, 29 ... projection, 30 ... upper surface, 31, 32 ... inclined surface, 33 ... curved surface, 40 ... clamping means, 41 ... Arm, 42 ... Elevating means, 43 ... Compressed air supply means, 44 ... Injectant supply means, 45 ... Boat

Claims (9)

A ground improvement device for improving the bottom of the water,
A hollow member installed so as to extend from the ground to the water surface;
An air injection pipe that is provided along the longitudinal direction adjacent to the outer surface of the hollow member, and that injects compressed air toward the water surface inside the hollow member;
A drilling device comprising a drilling member that is lowered to the ground through the inside of the hollow member, excavates the ground and injects an injection material and mixes with the soil, and
The excavation member includes a hollow shaft body, a spiral blade provided around the shaft body, a protrusion provided so as to protrude in a radial direction of the spiral blade from the outer periphery of the spiral blade , Two or more injection pipes that pass through the inside of the shaft body, pass through the wall surface of the central portion of the shaft body, and extend to the lower side of the protruding portion along the lower surface of the spiral blade,
The protrusion is provided so as to protrude toward the excavation direction also at the tip of the shaft body and the lower surface of the spiral blade, and is tapered toward the rotation direction during excavation at the protrusion of the protrusion. A ground improvement device characterized in that a chip made of a material that is more easily worn than the protruding portion is attached.   The ground improvement device according to claim 1, wherein a plurality of the air injection pipes are provided in the middle of the longitudinal direction so as to penetrate the wall surface of the hollow member and inject the compressed air toward the water surface.   The shaft body is formed to have a large diameter at a central portion along a length direction and a small diameter at both end portions, and the spiral blade has a blade diameter from the both end portions toward the central portion. The ground improvement device according to claim 1 or 2, wherein a plurality of the protrusions formed so as to be large and provided on the outer periphery of the spiral blade are provided on the outer periphery of the blade having at least a maximum blade diameter.   A plurality of the protrusions provided on the outer periphery of the spiral blade are provided at equal intervals so that adjacent protruding tips or straight lines connecting the tips of the protrusions do not contact the outer periphery of the spiral blade. The ground improvement apparatus of Claim 3.   The ground improvement device according to any one of claims 1 to 4, further comprising a plurality of plate-like protrusions disposed on an upper surface and a lower surface of the spiral blade.   The ground improvement device according to any one of claims 1 to 5, further comprising suction discharge means for sucking and discharging the soil rising in the hollow member.   The ground improvement apparatus of any one of Claims 1-6 which injects the slurry or gas in which the solidification agent containing magnesium oxide (MgO) was disperse | distributed as the said injection material from the said 2 or more injection pipes. It said injection member comprises, in addition to MgO, silicon dioxide _(SiO 2), aluminum oxide _{(Al 2 O} 3), calcium oxide (CaO), including diiron trioxide _(Fe 2 _{O 3),} according to claim 7 Ground improvement equipment. The injection material is injected at a supply rate of 0.28 to 0.33 m ³ per minute at a pressure of 25 to 29 MPa, and a cylindrical improvement body having a diameter 2 to 8 times the maximum blade diameter is constructed. The ground improvement apparatus of any one of Claims 1-8.