JP3731886B2 - Drilling rod and chemical injection method - Google Patents

Description

  The present invention relates to ground improvement technology by chemical solution injection, and more particularly, to an excavation rod used for chemical solution injection and a chemical solution injection method.

The existing structure constructed above the soft ground may cause a cavity due to ground subsidence below it. When a cavity is generated, there is a problem in the stability of the existing structure, and therefore it is required to ensure its safety. In order to suppress the generation of such cavities or to fill the already generated cavities, various ground improvement methods using chemical injection are known. The present applicant has also proposed a ground improvement method as an example (see Patent Document 1).
JP 2003-96762 A

  The ground improvement method proposed by the present applicant uses a so-called free excavation method in which the ground is excavated linearly and curvedly while controlling the direction of excavation from the ground using a drilling rod incorporating a position information transmitter. In this way, the ground of the existing foundation will be improved. Therefore, it is excellent in that it is possible to improve the direct base board without using the existing structure while using the existing structure, but there is still room for improvement in the following points.

  That is, since the excavation rod used in the above ground improvement method is one that injects each of the two types of chemicals onto the ground separately, the improvement effect is unlikely to occur unless the chemicals are naturally mixed in the ground. There's a problem.

  In addition, the excavation rod used in the ground improvement method injects the chemical liquid outward in the radial direction of the rod. Therefore, the excavation rod is propelled to the lower position or the upper position of the ground improvement area, and the chemical liquid is injected upward or downward. become. However, if there is an injected region that has already been injected with a chemical solution at a position above or below the target ground improvement area, the drilling rod must be propelled to the injected region. The improvement effect may be impaired. Moreover, when the vicinity of the boundary between the side surface of the existing structure buried in the ground and the ground is the ground improvement zone, it is difficult to inject the chemical solution.

  The present invention has been made against the background of the prior art as described above. An object of the present invention is to reliably inject a chemical solution into the ground improvement area and to enhance the ground improvement effect by two types of chemical solutions.

  In order to achieve the above object, the present invention provides an excavation rod for ground excavation having an injection port for injecting a chemical solution flowing through two systems of chemical solution passages toward the ground, while providing the injection port on the front end surface along the excavation direction. An excavation rod characterized in that a mixing chamber communicating with the injection port and each chemical solution passage is provided.

  Since this excavation rod is provided with a mixing chamber communicating with the chemical solution injection port and each chemical solution passage, two kinds of chemical solutions are mixed in advance in the mixing chamber and then injected onto the ground. Therefore, a high ground improvement effect can be exhibited because two kinds of mixed chemicals penetrate directly into the ground. Further, the mixed chemical liquid is injected from an injection port provided on the front end face of the excavation rod. Therefore, there is a problem with the conventional excavation rod that injects the chemical solution radially outward as described above, that is, the existing structure where the injected region exists above or below the ground improvement region, or is buried in the ground Even in the case where the vicinity of the boundary between the side surface of the object and the ground is the ground improvement region, it is possible to inject the chemical without difficulty by side injection.

  The excavation rod is configured such that the mixing chamber is provided at a position close to the front side of the injection port.

  According to this, for example, the ground improvement effect exhibited by the mixed chemical solution such as the mixed chemical solution is hardened can be suppressed from occurring in the excavating rod. Therefore, if the ground improvement effect exhibited by the mixed chemical solution does not occur in the excavation rod, for example, the reaction time of the mixed chemical solution is slow, the position away from the injection port (for example, the rear end position of the rod containing the position information transmitter) Etc.) may be arranged in the mixing chamber.

  The excavation rod is configured as a check valve attached to each end of the chemical passage that opens into the mixing chamber.

  According to this, the approach of the mixed chemical liquid into the chemical liquid passage is blocked by the check valve, and the ground improvement effect exhibited by the mixed chemical liquid can be suppressed from occurring in the chemical liquid passage.

  The excavation rod is configured to include a rod formed on the outer peripheral surface with a chemical liquid passage formed by a concave groove communicating with the longitudinal direction and a cover plate of the concave groove.

  This rod can be configured to accommodate a position information transmitter or the like that transmits position information in the ground within the pipe, and can secure a chemical solution passage. In this case, a large cross-sectional area can be secured by forming the concave groove as a square concave groove or by forming the concave groove as an arc-shaped concave groove whose width direction is along the circumferential direction of the rod.

  The excavation rod is configured as a thin-walled cylindrical part whose inside forms a mixing chamber. According to this, a mixing chamber with a large volume can be secured. In this case, the specific rod constituting the excavation rod may be a thin-walled cylindrical portion over the longitudinal direction, or may be configured to have a thin-walled tubular portion partially. Further, the mixing chamber may be constituted only by a thin cylindrical portion of a specific rod, or a thin cylindrical portion is formed on both of the connected rods, and the inside of these thin cylindrical portions is mixed into the mixing chamber. You may comprise as.

  The drilling rod can be configured such that at least one of the chemical liquid passages is a drilling fluid passage. According to this, it is not necessary to secure an independent passage for the drilling fluid.

  In order to achieve the above object, the present invention comprises a drilling rod and a position information transmitter interpolated in the drilling rod. According to the position information from the position information transmitter, the front end of the drilling rod is provided. Regarding the chemical injection method that performs drilling in a straight line and a curved line while injecting drilling fluid from the injection port in the direction of advancement and injecting the chemical liquid when it reaches the ground improvement zone, two chemical liquid passages and each chemical liquid are connected to the drilling rod. A chemical injection method characterized in that both chemical solutions are once mixed in the mixing chamber and then injected forward from the injection port to inject the chemical solution into the ground improvement region. provide.

  According to this, by approaching the ground improvement area by free excavation, the mixed chemical solution is injected from the injection port provided at the front end portion of the excavation rod. Therefore, there is a problem with the conventional excavation rod that injects the chemical solution radially outward as described above, that is, the existing structure where the injected region exists above or below the ground improvement region, or is buried in the ground Even in the case where the vicinity of the boundary between the side surface of the object and the ground is the ground improvement region, it is possible to inject the chemical without difficulty by side injection. In addition, since the two types of chemical solutions are once mixed in the mixing chamber and then injected, a high ground improvement effect can be exhibited by the mixed chemical solution directly penetrating into the ground.

  The said chemical | medical solution injection | pouring method is comprised as what uses the excavation rod of this invention mentioned above as an excavation rod. According to this, the advantage by the excavation rod of this invention is also acquired.

  According to the excavation rod and chemical injection method of the present invention, the chemical solution can be reliably injected into the target ground improvement region, and two kinds of chemical solutions can be injected into the ground improvement region in a mixed state. High ground improvement is possible.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Outline of excavation rod [FIGS. 1 to 4] : As shown in FIG. 1, the excavation rod 1 of this embodiment includes an excavation head 2, a monitor rod 3, and a storage rod 4 of a position information transmitter from the front end side in the excavation direction. The double pipe connection reducer 5, the coupling 6, and the extension rod 7 are connected to each other by screwing. The coupling 5 and the extension rod 6 are alternately screwed to the rear end portion of the extension rod 6 according to the required excavation length.

Excavation head 2 : The excavation head 2 excavates the ground, and as shown in FIG. 2, an inclined plate 8 that receives the earth pressure of the ground during excavation is bolted. An injection port 2a is opened at the front end surface of the excavation head 2, from which the excavation fluid and the mixed chemical solution are injected forward. The injection port 2a communicates with the passage 2b, and a housing portion 2c of a resin ball 9 that functions as a check valve is formed on the base end side of the passage 2b. The housing portion 2c is formed in the passage 10a. It is closed with a cap 10 that is formed through. Therefore, when the drilling fluid or the like is jetted, the ball 9 receives the fluid pressure and moves to the front end side of the housing portion 2c, but does not close the passage 2b, so that the drilling fluid or the like is jetted from the jet port 2a. . On the other hand, it is assumed that drilling fluid or the like flows backward from the injection port 2a. In this case, the ball 9 is fitted into the spherical concave portion 10b of the cap 10 and functions as a check valve, thereby preventing the backflow to the monitor rod 3.

Monitor rod 3 : As shown in FIG. 2, the monitor rod 3 has a thin cylindrical portion 3a. The thin cylindrical portion 3a is formed from the front end of the monitor rod 3 to the vicinity of the center, and the inside is a mixing chamber 3b. In the mixing chamber 3b, the end ports of the two paths 3c and 3d are opened separately.

  A check valve 11 is attached to each end port by screwing. The check valve 11 includes a cylindrical case 11a, an operating pin 11b, a coil spring 11c that urges the operating pin 11b, and a lid 11d that is threadably connected to the outer peripheral surface of the cylindrical case 11a. The cylindrical case 11a is formed with a hole 11e along the pricking direction and a hole 11f penetrating in the radial direction. The operation of the check valve 11 will be described later. The passage 3 c extending from the end port extends radially outward in the middle and opens on the outer peripheral surface of the monitor rod 3. On the other hand, the passage 3 d is formed through the monitor rod 3 in the longitudinal direction.

Storage rod 4 : The storage rod 4 stores the position information transmitter 12 as shown in FIGS. 2 and 3. The position information transmitter 12 incorporates a transmitter unit (not shown) that transmits position information in the ground so that the excavation rod 1 can freely excavate. As shown in FIG. 3, the storage rod 4 is formed with a plurality of transmitting portions 16 formed by resin-sealing through holes for transmitting electromagnetic waves transmitted from the position information transmitter 12. In the present embodiment, electromagnetic waves are transmitted as position information, position information in the ground is acquired based on the electromagnetic waves caught by a detector called a locator on the ground, and free excavation is controlled. What is bolted to both ends of the position information transmitter 12 is a cushioning material 13 made of a rubber-like elastic body. These are fixed by a fixture 14 that is screwed into the inner peripheral surface 4 a of the storage rod 4.

  On the outer peripheral surface 4b of the storage rod 4, two concave grooves 4c and 4d are formed which communicate with the longitudinal direction thereof. The bottom surfaces of the concave grooves 4c and 4d are one step lower inward in the radial direction than the outer peripheral surface 4b.

  Front holes 4e and 4f communicating with the inner peripheral surface 4a are formed through the front end sides of the concave grooves 4c and 4d. When the monitor rod 3 is connected to the storage rod 4, the front hole 4 e is in communication with the passage 3 c of the monitor rod 3, and the front hole 4 f is a gap between the fixture 14 and the rear end surface of the monitor rod 3. Through the passage 3d of the monitor rod 3.

  On the other hand, rear holes 4g and 4h communicating with the inner peripheral surface 4a are also formed through the rear end sides of the concave grooves 4c and 4d. When the double pipe connection reducer 5 is coupled to the storage rod 4, the rear hole 4g is aligned and communicated with the passage 5a of the double pipe connection reducer 5, and the rear hole 4h is connected to the fixture 14 and the double pipe. It communicates with the passage 5 b of the double pipe connection reducer 5 through a gap with the front end face of the connection reducer 5.

  As described above, the storage rod 4 is formed with two systems of passages in which the concave grooves 4 c and 4 d are closed by the lid plate 15. Accordingly, the housing space for the position information transmitter 12 is formed inside the storage rod 4, and conversely, even if the position information transmitter 12 is stored, two passages are secured.

Double pipe connection reducer 5 : The double pipe connection reducer 5 is formed with the aforementioned passages 5a and 5b as shown in FIG. The passage 5 a extends radially outward from the middle and opens on the outer peripheral surface of the double pipe connection reducer 5. On the other hand, the passage 5 b is formed so as to penetrate obliquely along the longitudinal direction of the double pipe connection reducer 5. An inner pipe connecting pipe 5c is coupled to the rear end port on the rear side of the passage 5a by screwing.

Coupling 6, extension rod 7 : The coupling 6 is a double tube rod. That is, it is composed of an outer tube 6a and an inner tube 6b. The inner pipe connection pipe 5c of the double pipe connection reducer 5 described above is connected to the front end of the inner pipe 6b by insertion. The inner tube 6 b is held inside the outer tube 6 a by an annular holder 17. The holder 17 is formed with a hole 17a communicating with the passage 6c between the outer tube 6a and the inner tube 6b and a hole 17b holding the inner tubes 6b and 7b.

  The extension rod 7 is also a double tube rod, and is composed of an outer tube 7a and an inner tube 7b. The inner tube 7b is connected to the rear end of the inner tube 6b of the coupling 6 by insertion. The holder 17 holds the inner pipe 7b inside the outer pipe 7a.

  The inner pipes 6b and 7b of the coupling 6 and the extension rod 7 and the holder 17 are joined and connected in advance by a welded portion 18, and the outer pipes 6a and 7a are fixed by bolts 19. The

Two passages : In the excavation rod 1 having the above-described configuration, the following two passages are formed. One of them is a passage between the outer tube 7a and the inner tube 7b of the extension rod 7, a passage 6c between the outer tube 6a and the inner tube 6b of the coupling 6, a passage 5b of the double tube connecting reducer 5, This is a first passage composed of the concave groove 4 d of the storage rod 4 and the passage 3 d of the monitor rod 3. The other is a second passage composed of the inner tube 7b of the extension rod 7, the inner tube 6b of the coupling 6, the passage 5a of the double tube connection reducer 5, the concave groove 4c of the storage rod 4, and the passage 3c of the monitor rod 3. . The first passage and the second passage function not only as a “chemical solution passage” but also as a drilling fluid passage. When a drilling fluid passage is used, either the first passage or the second passage may be used, or both may be used.

Outline of Chemical Solution Injection Method [FIGS. 5 to 8] : Next, a chemical solution injection method using the excavation rod 1 will be described. In the present embodiment, as an example of the construction method, as shown in FIG. 5, a construction method for injecting a chemical solution into the cavity 22 generated immediately below the tub pipe 21 embedded in the riverbed 20 will be described as an example. The riverbed 20 often has a ground structure in which a sandy ground 24 of soft ground is deposited on a clay layer 23. And, when the cavity 22 is generated around the dredged pipe 21 due to the settlement of the soft sandy ground 24, the dam body 25 is cracked and pulled out, and the safety is impaired. Needed. The chemical solution injection method according to the present embodiment includes a universal excavation process performed by a universal boring machine 26 installed on the riverbed 20 and a chemical solution injection process performed using an injection device (not shown).

Swivel excavation process [FIGS. 5 to 7] : As shown in FIG. 5, linear and curved free excavation is performed toward the cavity 22 by using the free boring machine 26 and the excavation rod 1. Specifically, the excavation rod 1 is obliquely penetrated into the ground while applying a rotational force and a propulsive force by the free boring machine 26.

  When excavating the ground, the drilling fluid is pumped to the first passage. Here, an example in which only the first passage is used will be described. When the drilling fluid is pumped to the first passage and reaches the monitor rod 3, the drilling fluid w1 opens the check valve 11 by the fluid pressure and flows into the mixing chamber 3b. Specifically, as shown in FIG. 6, the check valve 11 urges the operating pin 11b by a coil spring 11c to close the hole 11f, but the drilling fluid w1 pushes the operating pin 11b. The holes 11f and 11e of the cylindrical case 11a are opened, and flow into the mixing chamber 3b through the holes 11f and 11e. And it injects toward the front from the injection port 2a through the accommodating part 2c of the excavation head 2, and the channel | path 2b from the mixing chamber 3b.

  Further, the straight excavation in the free excavation is performed by applying a propulsive force while rotating the excavating rod 1 by the free boring machine 26. Curved excavation is performed by applying a propulsive force in a state where the rotation of the excavating rod 1 is stopped at a predetermined angle. Thus, the direction is changed by receiving the earth pressure from the ground by the inclined plate 8 and excavating in a curved shape. If free excavation is performed as described above, as shown in FIG. 7, it is possible to reach the cavity 22 below the tub tube 21 at a pinpoint from the side.

Chemical solution injection process (FIG. 8) : Then, the excavating rod 1 is connected from the universal boring machine 26 to the chemical solution injection device, and a predetermined chemical solution is pumped to both the first passage and the second passage. When each chemical solution reaches the monitor rod 3, as shown in FIG. 8, the two check valves 11 are opened and the respective chemical solutions w2 and w3 flow into the mixing chamber 3b and are mixed in advance. Through the injection port 2a. By side injection with respect to the cavity 22, the mixed chemical liquid w4 can be reliably injected into the cavity 22, and the mixed chemical liquid w4 in which two kinds of chemical liquids w2 and w3 are mixed in advance directly acts on the cavity 22, High ground improvement effect can be demonstrated. In addition, since the mixing chamber 3b is in a position close to the front side of the injection port 2a, the ground improvement action, that is, the hardening action does not occur inside the excavation rod 1.

Modification Example of Embodiment [FIGS. 9 and 10] : In the above-described embodiment, the example in which the mixing chamber 3b is provided in the monitor rod 3 has been described. For example, as illustrated in FIG. It is good also as forming a thin cylindrical part in both sides and making the inside into a mixing chamber. Further, as shown in FIG. 9B, a tube having a thin cylindrical portion as a whole length may be used for the monitor rod, and the inside thereof may be used as a mixing chamber.

  In the embodiment, the concave grooves 4c and 4d having a square cross section are illustrated as shown in FIG. 3, but the passage may be enlarged as an arc-shaped concave groove and a cover plate as shown in FIG.

  In the above embodiment, the monitor rod 3 is connected to the rear end portion of the excavation head 2, but if the ground improvement effect exhibited by the mixed chemical liquid does not occur in the excavating rod, for example, the reaction time of the mixed chemical liquid is slow, You may arrange | position a mixing chamber in the position away from the opening | mouth, for example, the rear-end part of the storage rod 4, etc.

The external appearance perspective view of the excavation rod by one Embodiment of this invention. Sectional drawing of the excavation rod (excavation head, monitor rod, storage rod) of FIG. FIG. 3 is a sectional view taken along line SA-SA in FIG. 2. Sectional drawing of the excavation rod (double pipe connection reducer, coupling, extension rod) of FIG. BRIEF DESCRIPTION OF THE DRAWINGS Outline explanatory drawing of the chemical injection method by one Embodiment of this invention. Operation | movement explanatory drawing of the monitor rod at the time of excavation. Explanatory drawing which shows the arrival state to a ground improvement area. Operation | movement explanatory drawing of the monitor rod at the time of chemical | medical solution injection | pouring. Sectional drawing which shows the modification of embodiment. Sectional drawing which shows the modification of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excavation rod 2 Excavation head 2a Injection port 3 Monitor rod 3b Mixing chamber 4 Storage rod 4b Outer peripheral surface 4c, 4d Groove | groove 12 Position information transmitter 15 Cover plate

Claims (5)

In the excavation rod for ground excavation having an injection port for injecting the chemical liquid flowing through the two chemical liquid passages toward the ground,
An excavation rod characterized in that an injection port is provided on a front end surface along the digging direction, and a mixing chamber is provided in communication with the injection port and each chemical solution passage.   The excavation rod according to claim 1, wherein the mixing chamber is provided at a position adjacent to the front side of the injection port.   The excavation rod according to claim 1 or 2, wherein a check valve is attached to each end portion of the chemical liquid passage that opens into the mixing chamber.   The excavation rod according to any one of claims 1 to 3, further comprising a rod formed with a chemical liquid passage formed of a concave groove communicating with the longitudinal direction and a cover plate of the concave groove on an outer peripheral surface. A drilling rod and a position information transmitter interpolated in the drilling rod are provided, and in accordance with the position information from the position information transmitter, a straight line while jetting drilling fluid from the injection port at the front end of the drilling rod In the chemical solution injection method of injecting the chemical solution when it reaches the ground improvement area,
The excavation rod is provided with two chemical channels and a mixing chamber for each chemical solution. After mixing both chemicals in the mixing chamber, the chemical solution is injected forward from the injection port to inject the chemical solution into the ground improvement area. A chemical injection method characterized by that.

Images