JP2008025175A - Soil improvement equipment and soil improvement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide soil improvement equipment and a soil improvement method, which enable construction to be inexpensively performed with high working efficiency, in the construction of a curved soil improvement body. <P>SOLUTION: This soil improvement equipment 10 comprises: an arc-shaped bent pipe 17 with a constant curvature; a drilling bit 20 which is provided at the leading end of the bent pipe 17 and equipped with a jet hole 20c for emitting a soil improving material under high pressure; and a soil-improving-material feeding pipe 30d which is provided in the bent pipe 17 so as to feed the soil improving material to the jet hole 20c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ground improvement device and a ground improvement method, and more particularly to a technique for constructing a curved ground improvement body.

  In order to construct an area such as an emergency parking zone in the interior space of the tunnel, a part of the segment constituting the tunnel may be cut and widened. When the ground to be excavated is soft, in order to prevent the ground from collapsing and falling rocks during excavation, conventionally, a ground improvement material is injected into the ground outside the widened area and consolidated to improve the ground strength. Construction to let you go.

For example, in Patent Document 1, first, an outer tube curved from a segment and an inner tube to which a drilling device is attached are simultaneously excavated to a predetermined position of the widening portion while confirming the excavation position with a position measuring device, and thereafter Pull out the inner pipe together with the excavator while leaving the outer pipe, insert the injection pipe into the outer pipe, and inject improvement material such as freezing agent or cement milk into the ground through the injection pipe, A ground improvement method for constructing an improved body is disclosed.
JP-A-4-281990

  However, in the ground improvement method disclosed in Patent Document 1, in constructing the ground improvement body, after excavating the ground to a predetermined position, the inner pipe to which the excavation device in the outer pipe is attached is once drawn, and the injection pipe is Since it is inserted again and the inner tube and the injection tube are exchanged, this exchange work takes time and effort.

  In addition, when a freezing agent is used for ground improvement, not only does it take time to freeze the ground before the excavation work, but it also takes time and effort to thaw the frozen area after the excavation work is completed. .

  In addition, when using improved materials such as cement milk for ground improvement, a large amount of injection and high injection pressure are required to make the ground improvement body equivalent to the strength when using a freezing agent. As a result, the cost increases and the surrounding ground may be lifted.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a ground improvement device and a ground improvement method that can be constructed at low cost with high work efficiency in constructing a ground improvement body that is curved.

In order to achieve the above object, the present invention is a ground improvement device for constructing a curved ground improvement body,
An arc-shaped curved pipe having a constant curvature;
A drilling bit provided at the tip of the curved pipe and having an injection hole through which a ground improvement material is injected;
It is provided in the said curved pipe, It is provided with the supply pipe | tube which supplies the said ground improvement material to the said injection hole (1st invention).

According to the ground improvement device of the present invention, since the excavation bit has the injection hole, the ground improvement material is injected by injecting the ground improvement material from the injection hole of the excavation bit when the pipe that has been excavated by the ground is pulled out. You can build your body. For this reason, it is possible to omit the replacement work of the ground improvement material injection pipe and the like, and the construction period can be shortened.
In addition, when the ground improvement material is injected into the ground, the ground around the injection hole is cut, and the ground thus ground and the ground improvement material are mixed and stirred or replaced, so the ground is improved over a wide range from the excavation hole. It is possible to construct a ground improvement body having high strength as a whole.
Moreover, since the ground improvement material can be injected into the ground from the deepest position of the drilling hole by providing the injection hole in the drilling bit, the ground improvement body can be constructed over the entire length of the drilling hole. .

According to a second aspect of the present invention, in the first aspect, the curved pipe includes an outer pipe and an inner pipe disposed inside the outer pipe with an inner circumference and a gap therebetween. To do.
According to the ground improvement device according to the present invention, the gap between the inner circumference of the outer pipe constituting the curved pipe and the outer circumference of the inner pipe is used as a passage for discharging the excavated earth, groundwater, etc. taken into the curved pipe to the outside. Therefore, it is possible to avoid a phenomenon in which the excavation bit does not move due to clogging of excavated ground or the like during excavation. Also, when injecting ground improvement material into the ground, excess ground improvement material, cut ground, or groundwater injected into the ground through this gap can be discharged to the outside. Can avoid the phenomenon of surrounding ground lifting.

  A third invention is characterized in that, in the second invention, the excavation bit is driven by a driving portion provided at a distal end portion of the inner pipe.

  According to a fourth invention, in any one of the second and third inventions, a packing is provided at a tip edge portion of the outer tube, the inner tube is movable in the tube axis direction in the outer tube, and the inner tube is The gap between the excavation bit and the packing can be opened and closed by moving in the tube axis direction.

  According to the ground improvement device according to the present invention, it is possible to open and close the gap between the excavation bit and the packing provided at the end edge portion of the outer pipe. As a result, by opening this gap during excavation, the excavated sediment or groundwater can be taken into the bent pipe and discharged from the proximal end of the bent pipe, while the bent pipe base such as when connecting the bent pipe is used. By closing this gap when the end is in an open state, water can be prevented from flowing out of the bent pipe.

According to a fifth invention, in any one of the second to fourth inventions, a cross section of the inner tube is substantially rectangular.
According to the ground improvement device according to the present invention, during excavation, the rotation angle around the pipe axis of the curved pipe indicating the approach direction of the curved pipe to the ground can be easily confirmed by visually referring to the cross section of the inner pipe. The accuracy in the direction of excavation can be improved.

According to a sixth invention, in any one of the first to fifth inventions, the curved pipe is configured by connecting a plurality of pipe bodies.
According to the ground improvement device of the present invention, a ground improvement body having a required size can be constructed even when the work space is limited, for example, in a tunnel space.

  According to a seventh invention, in any one of the first to sixth inventions, the ground improvement material is cement milk or mortar.

  An eighth invention is a ground improvement method for constructing a curved ground improvement body, which is provided at an arcuate curved pipe having a certain curvature and a tip portion of the curved pipe, and a ground improvement material is injected. The bent pipe is rotated while the excavation bit is rotated using a ground improvement device provided with a drilling bit having an injection hole and a supply pipe provided in the curved pipe and supplying the ground improvement material to the injection hole. By propelling in the tube axis direction, the curved pipe is allowed to enter the ground while excavating the ground in a curved shape, and the ground improvement material is sprayed from the injection hole while the curved pipe is pulled out from the ground, A cylindrical ground improvement body curved in an arc shape is formed by cutting the ground and mixing and stirring or replacing the cut ground and the ground improvement material.

  ADVANTAGE OF THE INVENTION According to this invention, when constructing | assembling the ground improvement body which curves, the ground improvement apparatus and the ground improvement method which can be constructed | assembled at low cost with high work efficiency can be provided.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram for explaining a ground improvement method according to the present embodiment. As shown in FIG. 1, in the ground improvement method according to the present embodiment, for example, when the ground 16 is soft when excavating the widened region 14 from inside the tunnel 12, in order to prevent the ground 16 from collapsing and falling rocks, The strength of the ground 16 corresponding to the outside of the widened region 14 is improved in advance by the ground improvement device 10.

  As shown in FIG. 1, the ground improvement device 10 includes a curved pipe 17, an arcuate curved pipe 17, a drilling bit 20 provided at the tip of the curved pipe 17, and a drilling hole 21 drilled by the drilling bit 20. And a propulsion unit 19 for propelling or pulling out.

  2 is an enlarged cross-sectional view of the distal end portion of the curved pipe 17 shown in FIG. 1, and FIG. 3 is an AA cross-sectional view of the curved pipe 17 of FIG.

  As shown in FIG. 2, the curved tube 17 includes an outer tube 22 formed in an arc shape having a certain curvature, and an inner tube 24 disposed therein. As shown in FIG. 3, the outer tube 22 has a substantially circular cross-sectional shape, and the inner tube 24 has a substantially rectangular cross-sectional shape. A plate-like centralizer 26 is provided on the inner peripheral surface of the outer tube 22, and the centralizer 26 supports a substantially rectangular apex of the inner tube 24, so that the inner tube 24, the outer tube 22, There is a gap between them. The centralizer 26 and the inner tube 24 are not fixed, and the inner tube 24 can freely move in the tube axis direction within the outer tube 22.

  The gap between the inner pipe 24 and the outer pipe 22 is a passage for guiding excavated earth and sand, groundwater, etc. taken from the tip of the bent pipe 17 to the base end of the bent pipe 17 and discharging it to the outside of the bent pipe 17. It becomes. Hereinafter, the gap 28 is referred to as a discharge passage 28. For example, a valve (not shown) is provided at the proximal end of the curved pipe 17 to discharge the fluid when the pressure of the excavated earth and sand discharged to the outside reaches a predetermined pressure. The earth and sand guided to the base end portion of the curved pipe 17 is discharged to the outside through this valve.

  A supply pipe 30 having a plurality of pipe lines 30a to 30d is inserted into the inner pipe 24. These pipe lines 30a to 30d are used as an oil feed pipe 30a, an air supply pipe 30b, a water supply pipe 30c, and a ground improvement material supply pipe 30d, which will be described later. As shown in FIG. 1, the curved pipe 17 is configured by sequentially connecting a plurality of pipe bodies 18. Correspondingly, the outer pipe 22 and the inner pipe 24 can be connected between the pipes. A connecting portion 32 (see FIG. 2) is provided. The pipe connecting portion 32 has a sealed structure so that fluid can be prevented from entering and leaching between the inside and outside of the pipe.

  FIG. 4 is an enlarged cross-sectional view of the pipe connecting portion 32. As shown in FIG. 4, the end portions of the outer tube 22 and the inner tube 24 are formed by male end portions 22a and 24a that are notched on the outer side and female end portions 22b and 24b that are notched on the inner side. The portions 22a and 24a are fitted inside the female end portions 22b and 24b. In addition, the sealing property in the pipe connection part 32 is ensured by packing 34 being interposed between male end part 22a, 24a and female end part 22b, 24b. The tube connecting portion 32 is configured such that the bolt 36 penetrates from the outside of the female end portions 22b and 24b and is screwed to the male end portions 22a and 24a. A concave portion 38 for accommodating the head of the bolt 36 is formed on the outer peripheral surfaces of the female end portions 22b and 24b so as not to protrude from the outer peripheral surfaces of the female end portions 22b and 24b. With the above configuration, the male end portions 22a and 24a and the female end portions 22b and 24b are brought into close contact with each other so that the inside and outside of the tube can be maintained. Even when the tube is moved in the tube axis direction, the protrusion from the outer periphery of the tube There is no problem of catching on things.

  Referring again to FIG. 2, the distal end portion of the curved pipe 17 is provided with a hydraulic motor 40 attached to the inner side of the inner pipe 24 and an excavation bit 20 that is driven by the hydraulic motor 40 and rotates.

  The hydraulic motor 40 is driven by hydraulic oil supplied from a hydraulic pump (not shown) installed in the tunnel 12 through an oil feeding pipe 30 a in a supply pipe 30 inserted into the inner pipe 24. The excavation bit 20 excavates the ground 16 in an arc shape by propelling the curved pipe 17 by the propulsion unit 19 while rotating the entire excavation bit 20 by the hydraulic motor 40.

  The excavation bit 20 includes a substantially cylindrical steel main body 20a having the same outer diameter as the outer tube 22, and a bit 20b provided on the excavation surface side of the steel main body 20a, and the outer peripheral surface of the steel main body 20a. Is provided with an injection hole 20c for high-pressure injection of air, water, and ground improvement material.

  The injection holes 20c are provided, for example, at two positions on the outer peripheral surface of the steel main body 20a, and the air supply pipe 30b, the water supply pipe 30c, and the ground improvement material supply pipe 30d in the supply pipe 30 are connected to each other. Has been. Then, a high-pressure pump (not shown) for supplying air, water and ground improvement material installed in the tunnel 12 is supplied through each supply pipe, and a fluid in which air, water and ground improvement material are mixed is supplied. It is injected from the injection hole 20c. The injected fluid cuts the ground 16 around the curved pipe 17 by its pressure, and the ground improvement material and water in the fluid are mixed and stirred or replaced to form a ground improvement body. Become.

  In addition, a packing 42 is provided at the distal end edge portion of the outer tube 22, and the gap between the excavation bit 20 and the packing 42 can be opened and closed by moving the inner tube 24 in the outer tube 22 in the tube axis direction. It is like that.

  FIG. 5 is an enlarged cross-sectional view showing the positional relationship between the excavation bit 20 and the packing 42 when (a) excavating and (b) when the curved pipe 17 is connected.

  As shown in FIG. 5A, during excavation, a state where a gap between the excavation bit 20 and the packing 42 is maintained is maintained. As a result, excavated earth and sand, groundwater, and the like are taken from the gap and discharged to the outside of the curved pipe 17 through the discharge passage 28.

  On the other hand, as shown in FIG. 5B, the gap between the excavation bit 20 and the packing 42 is closed when the outer tube 22 or the inner tube 24 is connected. As a result, since groundwater or the like does not enter through the gap between the excavation bit 20 and the packing, even when the proximal end portion of the curved pipe 17 is open, such as during connection work, the water discharged from the pipe is not discharged. I don't get up.

  Referring to FIG. 1 again, the propulsion device 19 includes a holding portion 19a that can hold the bent tube 17, a rail 19b that guides the horizontal movement of the holding portion, and an extendable jack 19c that moves the holding portion 19a. And a guide portion 19d for guiding the sandwiched bent pipe 17 to the ground 16. Then, the curved pipe 17 is clamped by the clamping portion 19 a and the jack 19 c is expanded and contracted, whereby the curved pipe 17 can be pushed into the ground 16 and pulled out from the ground 16.

  In addition, from the tunnel 12, the cross section of the inner pipe 24 can be referred to visually, and by confirming the rotation angle around the pipe axis of the cross section, confirm the approach direction of the curved pipe 17 to the ground, According to this approach direction, an external force is applied to the curved pipe 17 from the clamping portion 19a during excavation to adjust the entrance direction of the curved pipe 17 so that the trajectory of the excavation can be corrected.

  Further, the propulsion unit 19 is attached to a work table 44 fixed in the tunnel 12, for example, so as to be able to maintain a reaction force from the curved pipe 17 propelling the ground 16.

  Next, a specific ground improvement method using the ground improvement device 10 described above will be described. 6-8 is a figure for demonstrating the ground improvement method by the ground improvement apparatus 10, FIG. 6 is the time of construction preparation, FIG. 7 is the time of excavation, FIG. 8 is a figure which shows the time of ground improvement body construction. .

  As shown in FIG. 6, first, the curved pipe 17 is installed in the propulsion unit 19 installed at a predetermined position in the tunnel 12, and the distal end portion where the excavation bit 20 is provided is connected to the guide pipe 48 provided in the segment 46. Insert. In addition, what was constructed | assembled in advance with the unreinforced concrete or FRP concrete is arrange | positioned in the segment 46 which is a starting position of ground excavation so that excavation may not be prevented by a reinforcing bar. Moreover, it is preferable to use what the water stop packing (not shown) for preventing the water discharge from the ground 16 etc. is attached to the insertion port of the guide pipe 48. FIG.

  As shown in FIG. 7, during excavation, the hydraulic motor 40 at the tip of the inner pipe 24 is driven to rotate the excavating bit 20, and the curved pipe 17 is propelled into the ground 16 by the propulsion unit 19. The curved pipe 17 is advanced into the ground 16 while sequentially repeating the connection of the pipe bodies 18. During excavation, muddy water or the like may be ejected from the injection holes 20c to promote cooling of the excavation bit 20, intake of excavation pieces into the curved pipe 17, and discharge to the outside. In this way, excavation is performed until the tip of the bent tube 17 reaches the segment 46.

  As shown in FIG. 8, after excavation is completed, the ground improvement material is high-pressure injected from the injection hole 20 c of the excavation bit 20 while the curved pipe 17 penetrating the ground 16 is pulled out by the propulsion device 19, thereby excavating the hole 21. A cylindrical ground improvement body 50 that is curved in an arc shape is constructed by cutting the surrounding ground 16 and mixing and agitating or replacing the cut ground and the improvement material. Cement milk or mortar is used as the ground improvement material.

  After the ground improvement body 50 constructed as described above is cured for a predetermined period and cured, the widened region 14 can be subsequently cut.

  According to the ground improvement device 10 and the ground improvement method according to the present embodiment described above, the following effects can be obtained.

  (1) Since the excavation bit 20 includes the injection hole 20c through which high pressure is injected, the ground improvement material is injected from the injection hole 20c of the excavation bit 20 when the bent pipe 17 that has been excavated through the ground 16 is pulled out. Thus, the ground improvement body 50 can be constructed. For this reason, it is possible to omit the replacement work of the ground improvement material injection pipe and the like, and the construction period can be shortened.

  (2) When the air, water, and the ground improvement material are jetted into the ground 16 at a high pressure, the ground 16 around the injection hole 20c is cut, and the ground 16 and the ground improvement material that have been cut are mixed and stirred or replaced. Therefore, the ground can be improved over a wide range from the excavation hole 21, and the ground improvement body 50 having high strength as a whole can be constructed.

  (3) Since the excavation bit 20 is provided with the injection hole 20 c, the ground improvement material can be injected into the ground 16 from the deepest position of the excavation hole 21. 50 can be built.

  (4) Since the curved pipe 17 is configured by connecting the pipe bodies 18, the ground improvement body 50 having a necessary size can be constructed even when the work space is limited like the tunnel 12.

  (5) Since the gap between the outer pipe 22 and the inner pipe 24 constituting the curved pipe 17 can be used as a discharge passage 28 for discharging excavated earth and sand or groundwater taken into the curved pipe 17 to the outside, excavation The phenomenon that the excavation bit 20 sometimes does not move due to clogging of excavated ground or the like can be avoided. In addition, when the ground improvement material is injected into the ground 16 at a high pressure, excess ground improvement material, cut ground, groundwater, or the like injected into the ground 16 can be discharged to the outside through the discharge passage 28. It is possible to avoid the phenomenon that the surrounding ground is lifted by the improvement material.

  (6) By moving the inner tube 24 in the tube axis direction, the gap between the excavation bit 20 and the packing 42 provided at the distal end edge of the outer tube 22 can be opened and closed. By opening this gap during excavation, the excavated soil and groundwater can be taken into the curved pipe 17 and discharged from the proximal end, while the proximal end of the curved pipe 17 during the connecting operation of the curved pipe 17 is provided. By closing this gap when in an open state, it is possible to prevent water from flowing out of the curved pipe 17.

  (7) Since the cross section of the inner pipe 24 is formed in a substantially rectangular shape, the rotation angle around the pipe axis of the curved pipe 17 indicating the approach direction of the curved pipe 17 to the ground 16 is changed to the cross section of the inner pipe 24. Since it can confirm easily by referring visually, the precision of an excavation direction can be improved. In addition, the rotational reaction force received from the excavation bit 20 can be easily suppressed by a configuration in which a substantially rectangular apex is supported by the centralizer 26 in the outer tube 22.

  In addition, according to the propulsion unit 19 according to the present embodiment, there is a configuration in which the reaction force applied to the propulsion unit 19 is supported by the pressing force from the side opposite to the propulsion direction of the propulsion unit 19, but the configuration is not limited thereto. The reaction force may be received and supported by a tensile force from the propulsion direction side of the propulsion unit 19 by being fixed to the segment 46 on the propulsion direction side. As a result, it is not necessary to install a support member on the side opposite to the propulsion direction of the propulsion unit 19, so that the space in the tunnel 12 can be used effectively.

  In the above-described embodiment, the present invention has been applied to construct the widened region 14 in the tunnel 12. However, the present invention is not limited to this. For example, in order to improve the ground strength below the existing structure, The present invention can also be applied to the case where a ground improvement body is constructed by bending the curved pipe 17 from the ground position on the side of the object toward the ground below the structure.

It is explanatory drawing for demonstrating the ground improvement method which concerns on this embodiment. It is an expanded sectional view of the front-end | tip part of the curved pipe 17 shown in FIG. It is an AA cross-sectional view of the curved pipe 17 of FIG. FIG. 4 is an enlarged cross-sectional view of a pipe connecting part 32. It is an expanded sectional view which shows the positional relationship of the clearance gap between the excavation bit 20 and the packing 42 at the time of (a) excavation, (b) at the time of the curved pipe 17 connection. It is a figure for demonstrating at the time of construction preparation in the ground improvement method by the ground improvement apparatus. It is a figure for demonstrating at the time of excavation in the ground improvement method by the ground improvement apparatus. It is a figure for demonstrating at the time of the ground improvement body construction in the ground improvement method by the ground improvement apparatus.

Explanation of symbols

10 Ground improvement device, 17 curved pipe, 18 pipe,
20 drilling bit, 20a steel body, 20b bit, 20c injection hole,
22 outer tube, 22a outer tube male end, 22b outer tube female end,
24 inner tube, 24a inner tube male end, 24b inner tube female end,
28 discharge passage, 30 supply pipe, 30a oil supply pipe,
30b Air supply pipe, 30c Water supply pipe, 30d Ground improvement material supply pipe,
32 pipe connection part, 42 packing, 50 ground improvement body

Claims (8)

A ground improvement device for constructing a curved ground improvement body,
An arc-shaped curved pipe having a constant curvature;
A drilling bit provided at the tip of the curved pipe and having an injection hole through which a ground improvement material is injected;
A ground improvement device comprising: a supply pipe provided in the curved pipe and supplying the ground improvement material to the injection hole.   2. The ground improvement device according to claim 1, wherein the curved pipe includes an outer pipe and an inner pipe disposed inside the outer pipe with an inner circumference and a gap therebetween.   The ground excavation device according to claim 2, wherein the excavation bit is driven by a drive unit provided at a distal end portion of the inner pipe.   A packing is provided at a distal end edge of the outer tube, and the inner tube is movable in the tube axis direction in the outer tube. By moving the inner tube in the tube axis direction, the excavation bit and the packing The ground improvement device according to claim 2 or 3, wherein the gap can be opened and closed.   The ground improvement device according to any one of claims 2 to 4, wherein a cross section of the inner pipe is substantially rectangular.   The ground improvement device according to any one of claims 1 to 5, wherein the curved pipe is configured by connecting a plurality of pipe bodies.   The ground improvement device according to any one of claims 1 to 6, wherein the ground improvement material is cement milk or mortar. A ground improvement method for constructing a curved ground improvement body,
An arc-shaped curved pipe having a certain curvature; a drilling bit provided at a tip of the curved pipe and having a spray hole through which a ground improvement material is injected; and provided in the curved pipe, the ground improvement material Using a ground improvement device comprising a supply pipe for supplying to the injection hole,
By pushing the curved pipe in the direction of the pipe axis while rotating the excavation bit, the curved pipe enters the ground while excavating the ground in a curved shape,
While extracting the curved pipe from the ground, the ground improvement material is sprayed from the injection hole to cut the ground, and the cut ground and the ground improvement material are mixed and stirred or replaced into an arc shape. A ground improvement method characterized by forming a cylindrical ground improvement body curved in a straight line.

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