JP2020056221A - Ground support force checking method - Google Patents

Abstract

To provide a ground support force checking method capable of improving accuracy of a measurement value of ground strength.SOLUTION: A ground support force checking method is a method for forming a pile hole by vertically connecting a plurality of auger rods 10, 20 and drilling the ground A using an auger head 30 provided on a tip of the tip auger rod 10 by rotary driving of the plurality of auger rods 10, 20. The method includes: by lowering a penetration rod 52 provided in a hollow part of the tip auger rod 10 so as to be vertically movable in a vertically extending solidification material force-feed pipe 53, pushing out a measurement cone 51 to the outside of the auger head 30 and making the measurement cone penetrate into the ground; and, using a three-component sensor 54 positioned between the penetration rod 52 and the measurement cone 51, measuring resistance force in making the measurement cone 51 penetrate.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for confirming a ground supporting force.

  In the construction of a pile or the like, an excavation hole (pile hole) is formed by rotating and driving an earth auger provided in an excavator such as a pile driving machine and penetrating the ground.

  When embedding a ready-made concrete pile, it is necessary to insert the tip of the pile to a support layer having a predetermined or higher supporting force. Generally, when excavating using an earth auger, an integrated current value (a product of a current value in consideration of the time required for excavation and an excavation time) in a device for driving a spiral auger is used to detect an earth current in the support layer. Check that the tip of the auger has reached.

  However, erroneous results have been caused by the gravel taken in by excavation getting stuck between the inner surface of the pile and the blades of the spiral auger, and the sediment remaining inside the pile to increase peripheral friction. Judgment may occur. Therefore, in addition to the above determination, it is preferable to confirm whether the tip of the earth auger has reached the support layer.

  Therefore, for example, in Patent Document 1, a lower rod having a conical tip is provided at the lower end of the auger screw, and the insertion resistance when the lower rod is inserted into the ground by a fluid pressure cylinder is measured. And measuring the strength of the ground.

  In Patent Document 2, a measuring cone connected to the tip of a pressing rod is provided in an auger head of a spiral auger, and the measuring cone is pressed against the ground to measure a pressing force and a press-fitting amount. It is disclosed to measure the intensity of A hydraulic cylinder connected to the upper end of the pressing rod is arranged in a gear box provided at the upper end of the auger rod, and a load cell is provided at the upper end of the hydraulic cylinder. The pressing rod is formed in a tubular shape, and the inside thereof is used as a passage for a solidifying agent such as cement milk.

Japanese Utility Model Publication No. 55-16990 Japanese Patent No. 30624478

  However, in the technology disclosed in Patent Document 1, since the resistance force when the lower rod is inserted into the ground is determined from the hydraulic pressure acting on the piston of the fluid pressure cylinder, the weight of the lower rod and the lower rod An error may occur in the measured value due to the acting frictional force or the like.

  In the technique disclosed in Patent Document 2, since the measuring cone presses against the ground via the pressing rod or the like, an error may occur in the measured value due to the weight of the pressing rod, frictional force acting on the pressing rod, and the like. .

  In view of the above points, an object of the present invention is to provide a method for confirming a ground supporting force capable of improving the accuracy of a measured value of ground strength.

In the method for confirming a ground supporting force according to the present invention, a plurality of auger rods are connected in a vertical direction, and the plurality of auger rods are driven to rotate. A method of confirming the bearing capacity of the ground using a pile hole forming device that forms a pile hole by doing
The measuring cone connected to the lower end of the rod is pushed out of the auger head by moving a rod provided vertically movably in a tube extending vertically in the hollow part of the auger rod at the tip, to the outside of the auger head. And measuring the resistance when the measuring cone is penetrated into the ground by a resistance measuring means located between the rod and the measuring cone.

  According to the method for confirming the ground supporting force of the present invention, the measuring cone is made to penetrate into the ground, and the resistance force at that time is measured. From this, the ground support force can be confirmed by a normal static cone penetration test or a test similar thereto. Furthermore, since the resistance measuring means is measured by the resistance measuring means located between the rod and the measuring cone, it is possible to measure the resistance without being affected by the weight of the rod and the frictional force acting on the rod. it can. Thus, it is possible to improve the accuracy of the measured value of the ground strength.

  In the method for confirming a ground supporting force according to the present invention, it is preferable that displacement in a vertical direction of the rod is measured by displacement measuring means provided in the auger rod at the tip.

  In this case, since the displacement of the rod in the vertical direction is measured by the displacement measuring means provided in the auger rod at the tip, the displacement of the rod is indirectly measured by the measuring means provided outside the auger rod or in the second or subsequent auger rod. The displacement of the rod can be measured with higher accuracy than in the case where the measurement is performed periodically, and the accuracy of the measured value of the ground strength can be further improved.

  Further, in the method for confirming a ground supporting force according to the present invention, it is preferable that after the ground is excavated by the auger head to form the pile hole, a solidified material is injected into the surrounding ground via the pipe.

  In this case, since the solidified material pumping tube for pressure-conveying the solidified material and the tube in which the rod can move up and down are shared, the configuration can be simplified. However, the pile hole forming device of the present invention can be applied to a method that does not use a solidified material, and in this case, there is no solidified material pumping tube in the first place.

  Further, in the method for confirming a ground supporting force according to the present invention, after injecting the solidifying material, the wing expander provided on the auger rod at the tip is deployed, and the plurality of auger rods are driven to rotate, thereby expanding the expander. It is preferable that the measuring cone is penetrated after the pile hole is expanded by a blade.

  In this case, it is possible to form an enlarged hole.

  Further, in the method for confirming a ground supporting force according to the present invention, when rotating the plurality of auger rods, a resistance value for obtaining a predetermined rotational driving force is estimated, and the estimated value of the resistance value is a predetermined reference value. Is exceeded, or when the excavation depth exceeds a predetermined depth, the rotation drive is preferably stopped.

  In these cases, in these cases, the tip of the auger head may have reached the support layer, and it is possible to stop excavation at this depth.

  Further, in the method for confirming the supporting force of the ground according to the present invention, when connecting the auger rod to the upper end of the auger rod at the upper end, a fluid is supplied to a mechanism for moving the rod downward, and the auger rod at the upper end is A fluid pipe arranged inside the auger rod connected to the fluid pipe passing therethrough, and a pipe arranged inside the auger rod connected to the pipe passing inside the auger rod at the upper end. Are preferably connected.

  In this case, the connection between the auger rods can be simplified.

  Further, in the method for confirming the ground supporting force of the present invention, when the auger rod is connected to the upper end of the auger rod at the upper end, the auger rod is connected to a resistance force measuring means for measuring a resistance force when the measurement cone is penetrated. The first protection cover provided at the end of the first communication line is removed, and the second protection cover provided at the end of the second communication line disposed outside the auger head at the upper end is removed. After these, it is preferable to connect the end of the first communication line to the end of the second communication line.

  In this case, the connection part of the communication line can be protected by the protective cover.

1 is a schematic side view of a pile hole forming device used in a method for confirming a ground supporting force according to an embodiment of the present invention. The schematic side view which shows a part of auger rod. FIG. 3 is a schematic cross-sectional view showing a part of a first-stage cylindrical body. FIG. 3 is a schematic sectional view showing a part of a first auger rod. FIG. 5 is a schematic sectional view taken along line VV of FIG. 4. The top view which shows the male joint of the rear end part of the 1st auger rod. The top view which shows the male joint of the rear end part of the 2nd or more auger rods. FIG. 2 is a schematic side view showing the vicinity of a connection part of a communication line. The figure which shows the state in which the protective tube is penetrated by the through-hole of a spiral wing. The figure which shows the state in which the protective tube was fixed to the auger rod. 5 is a flowchart of a method for confirming a supporting force using a pile hole forming device.

  A pile hole forming apparatus 100 that can be used in the method for confirming a ground support force according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, when excavating a pile hole of a ready-made pile using the earth auger 110, the pile hole forming apparatus 100 confirms that the tip of the earth auger 110 has reached the support layer. It is equipped with a ground strength confirmation mechanism that can perform

  Here, a description will be given of a case where the pile hole forming apparatus 100 is applied to a method of injecting a solidifying material such as cement milk from the auger head 30 as a consolidation liquid, out of the method of embedding a ready-made pile using the earth auger 110. . Concretely, it is a construction method such as a pre-boring method such as a cement milk method, a middle digging method such as a middle digging method, and a rotating method such as a rotating method.

  The pile hole forming apparatus 100 mainly includes an earth auger 110 that forms a drilling hole for driving a pile or the like, an earth auger driving apparatus 120 that is installed on the site and that drives the earth auger 110 to rotate and penetrate the ground A. It is composed of Although not shown, a solidifying material tank for storing a solidifying material such as cement milk is also provided.

  The earth auger 110 is rotatably driven by the auger head 30 which is guided by the column 121 and moved downward while being held movably in the vertical direction by a steady rest 122 provided on the column 121 of the earth auger driving device 120. , Into the ground A.

  As a result, the earth auger 110 penetrates the ground A, and the excavation hole is formed vertically downward. Then, by changing the auger head 30 reaching the lower part of the support 121 to the upper part of the support 121 and repeating the addition of the auger rod 20 to the earth auger 110 penetrating into the ground A, a predetermined design is achieved. A borehole of a depth is formed.

  The earth auger 110 is formed by connecting a plurality of auger rods 10 and 20 in a vertical direction, and an auger head 30 is provided at the tip (lower end) of the auger rod 10 at the forefront (lower end).

  As shown in FIG. 2, the number and length of the auger rods 10 and 20 to be connected are determined according to the depth of the pile hole to be excavated. The auger rods 20 other than the first (most advanced) auger rod 10, that is, the second and subsequent auger rods 20 have the same structure. These auger rods 20 are cylindrical bodies, and spiral wings (screw) 20a are fixed to the outer peripheral surface in order to send excavated earth and sand upward.

  The first auger rod 10 has a structure in which a plurality of, here five, cylindrical bodies 11 to 15 are connected. These cylindrical bodies 11 to 15 are configured to be separable from the adjacent cylindrical bodies 11 to 15 respectively. Flanges 11b to 15b are formed at ends of the cylindrical bodies 11 to 15 on the connection surface side with the cylindrical bodies for connection with the adjacent cylindrical bodies 11 to 15, respectively.

  Although not shown in detail, a through hole is formed in each of the flanges 11b to 15b, and the female screw portion of the nut is screwed with the male screw portion of the bolt in a state where the bolt is inserted into the corresponding through hole. Thereby, the adjacent cylindrical bodies 11 to 15 are fixed. Male joints 10b, 20b are provided at the rear ends of the auger rods 10, 20, and female joints 20c are provided at the distal ends of the second and subsequent auger rods 20, respectively. Then, by connecting the male joints 10b, 20b and the female joint 20c, the adjacent auger rods 10, 20 are fixed to each other.

  Spiral blades 11a to 15a are also fixed to the outer peripheral surfaces of the cylindrical bodies 11 to 15 similarly to the auger rod 20. The spiral blades 11a to 15a are formed so as to be continuous as much as possible. Here, the spiral blades 11a to 15a are formed up to the side surfaces of the flanges 11b to 15b, whereby the spiral blades 11a to 15a are continuous. Accordingly, it is possible to improve the excavation efficiency by rotating the auger rod 10.

  An auger head 30 is provided at a front end (lower end) of the first-stage (most advanced) cylindrical body 11. Specifically, a plurality of excavation bits 41 are attached to the tip of a spiral blade 11 a fixed to the outer peripheral surface of the cylindrical body 11.

  Furthermore, as shown in FIG. 3, here, the cylindrical body 11 is provided with an expandable head 42 that can be expanded and closed. This enlarged head 42 is composed of a plurality of, here two enlarged wings 42a. Each enlarged wing 42a has a middle portion rotatably supported by a shaft 11c provided outside the cylindrical body 11, and a plurality of excavation bits 42b is attached to a tip portion. The expansion wing 42 a of the expansion head 42 is expanded and closed by a hydraulic cylinder 43 built in the cylindrical body 11.

  The other end of each of the enlarged wings 42a is fitted into a depression 43b provided on the outer periphery of the rod 43a of the hydraulic cylinder 43. The hydraulic cylinder 43 has a vertically extending hole formed at the center thereof, and has a slender donut shape as a whole.

  Further, a first fluid pipe 44 for flowing a fluid such as oil into or out of the oil chamber S1 above the rod 43a and an oil chamber S2 below the rod 43a. A second fluid pipe 45 (not shown) for inflowing a fluid or discharging a fluid such as oil in the oil chamber S2 is provided in the cylindrical body 11. An end of each of the fluid pipes 44 and 45 is connected to a connection (connector) 46 a provided at an upper end of the cylindrical body 11.

  The expansion head 42 is configured as described above, and as shown by a solid line in FIG. 3, a fluid flows in through the first fluid pipe 44 and the oil chamber S1 expands, so that the rod 43a Moving downward, each expanding wing 42a opens outward, and the expanding head 42 expands. On the other hand, as shown by the two-dot chain line in FIG. 3, the fluid flows in through the second fluid pipe 45, and the oil chamber S2 expands, so that the rod 43a moves upward and each expanding wing 42a moves inside. , And the magnifying head 42 closes.

  Further, a measurement cone 51 used in a cone penetration test is provided in an opening 11d formed at the tip of the auger head 30 and the cylindrical body 11. The measuring cone 51 has a conical shape with an acute angle so that it can penetrate the support layer, and is penetrated into the ground A (see FIG. 1) by a penetrating rod 52 connected to a rear end (upper end). .

  The penetration rod 52 is slidably provided in a tube 53 fixed to the cylindrical body 11. Here, the penetrating rod 52 is provided in a solidified material pumping tube 53 provided at the center of the auger head 30 for conveying a solidified material such as cement milk. The solidified material pressure feed pipe 53 extends vertically in the center of the auger head 30 and is provided so as to pass through a through hole formed in the center of the hydraulic cylinder 43.

  It is not always necessary to provide the solidified material pumping tube 53 at the center of the hydraulic cylinder 43. However, if it is provided at a position other than the central portion, the hydraulic pressure hardly acts on the portion where the solidified material pumping tube 53 is installed, and the hydraulic cylinder 43 is pressed. This is not preferable because there is a possibility that bias may occur in the force to be applied. Note that the cross-sectional area of the solidified material pumping tube 53 in the first-stage cylindrical body 11 is larger than that of the second-stage cylindrical body 12 or later in the cross-sectional area of the penetrating rod 52. Preferably, it is larger by the integral.

  The distal end of the solidified material pumping tube 53 reaches the opening 11d via the communication hole 11e, and the measuring cone 51 is connected to the distal end of the penetrating rod 52 protruding from the distal end of the solidified material pumping tube 53 via the three-component sensor 54. Connected. The three-component sensor 54 measures three components of the measurement cone 51 such as tip resistance (qc), peripheral friction (fs), and pore water pressure (ud).

  The solidified material pumping pipe 53 is branched in a horizontal direction above the distal end thereof, and a plurality of injection holes 53a are provided at the distal ends of these branched horizontal portions. As described above, the ejection hole 53a of the solidified material pressurizing pipe 53 is provided in the peripheral portion above the tip of the auger head 30, and the solidified material is ejected in the horizontal direction.

  Further, it is preferable to provide a sealing means 55 at a lower end portion of the solidified material pumping tube 53 as far as possible, so as to prevent earth and sand from flowing into the solidified material pumping tube 53 from the outside. The sealing means 55 is earth and sand inflow prevention means for preventing earth and sand from flowing into the communication hole 11e from the outside.

  The sealing means 55 is made of, for example, an elastic material such as rubber, and has a structure which is pushed open from the inside by the projection of the measuring cone 51 and closed by a leaf spring or the like after the measuring cone 51 returns to the original position. It is a check valve (check valve). Separately from the sealing means 55, in order to closely contact the outer peripheral surface of the penetrating rod 52 and the inner peripheral surface of the solidified material pumping tube 53 with no gap, the vicinity of the tip of the penetrating rod 52 and the solidified material pumping tube 53 And a sliding packing 55a is mounted between them.

  Even when such a sliding packing 55a exists, the three-component sensor 54 is located below the sliding packing 55a. This makes it possible for the three-component sensor 54 to directly measure the reaction force from the tip of the measuring cone 51 without being affected by the weight of the penetrating rod 52 and the frictional resistance of the sliding packing 55a. Become.

  When the solidified material needs to be ejected downward as in the cement milk method or the like, a sealing means 55 having a weak sealing force enough to be opened by the pressure of the solidified material fed under pressure may be used.

  Further, the solidified material pressure feeding pipe 53 in the auger head 30 has the penetrating rod 52 built therein, so that the area through which the solidified material can pass is limited. Therefore, it is preferable to increase the inner diameter as compared with a normal one in order to ensure the amount of solidified material to be fed.

  The second-stage cylindrical body 12 has a central portion through which a penetration rod 52 is inserted vertically. Furthermore, in the second-stage cylindrical body 12, first and second fluid pipes 47 and 48 (second fluid) are connected to connection portions 46a connected to the first and second fluid pipes 44 and 45, respectively. The piping 48 (not shown in FIG. 3) is connected via a connecting portion 46b and arranged inside.

  Further, in the second-stage cylindrical body 12, a solidified material pumping tube 56 connected to the solidified material pumping tube 53 is also arranged inside. The solidified material pumping tube 53 has a portion that branches off and extends in the horizontal direction at the top of the first-stage cylindrical body 11, and is shifted radially outward from the center of the upper end of the cylindrical body 11. A connecting portion 57a connected to a connecting portion 57b at the end of the solidified material pressure feeding pipe 56 is provided in a part. As a result, in the second-stage cylindrical body 12, the solidified material pumping tube 56 extends in the vertical direction at a portion away from the central portion.

  Since the penetrating rod 52 moves up and down the branching position of the solidified material pumping tube 53, the tip portion existing above the horizontally extending portion of the solidified material pumping tube 53 so that the solidified material does not leak out. Is provided with an upper sliding packing 58. Then, the penetrating rod 52 extends through the upper sliding packing 58.

  As shown in FIG. 4, the third-stage cylindrical body 13 is provided with a hydraulic cylinder (jack) 71 that pushes the penetration rod 52 downward. The rear end (upper end) of the penetration rod 52 is fixed to the front end (lower end) of the rod 71 a of the hydraulic cylinder 71. The two fluid pipes 72 and 73 connected to the hydraulic cylinder 71 are also incorporated in the third-stage cylindrical body 13.

  Since the hydraulic cylinder 71 applies a load to the penetrating rod 52, its axial center preferably coincides with the axial center of the third-stage cylindrical body 13, similarly to the penetrating rod 52. In this case, in the third-stage cylindrical body 13, the solidified material pumping pipe 56 is arranged so as to be radially shifted from the axis center.

  When the rod 71 a of the hydraulic cylinder 71 extends, the penetrating rod 52 moves downward, and the measuring cone 51 (see FIG. 3) fixed to the tip of the penetrating rod 52 moves the auger head 30. It protrudes to the outside below the tip. It is preferable that the extension of the rod 71a of the hydraulic cylinder 71, such as the extension amount and the extension speed, that is, the projection of the measurement cone 51 be the same as the case where the penetration test is performed by a normal static cone penetration test. . Thereby, the relationship between the amount of penetration of the measuring cone 51 and the supporting force in the ordinary static cone penetration test can be used as it is.

  However, a mode different from the case where a penetration test is performed in a normal static cone penetration test may be employed. In this case, the relationship between the penetration amount of the measurement cone 51 and the supporting force needs to be obtained in advance by an experiment or the like. .

  The second-stage cylindrical body 12 preferably has a built-in steady rest 74 for preventing run-out, rotation, deformation and the like of the penetration rod 52. Here, the steady rest 74 is fixed between the upper end of the penetrating rod 52 and the tip of the rod 71 a of the hydraulic cylinder 71. However, the steady rest 74 may be fixed to another part of the penetration rod 52.

  As shown in FIG. 5, the steady rest 74 has an outer shape following the shape of the inner surface of the cylindrical body 12, and is here formed in a substantially disk shape. In the penetration test, the measuring cone 51 needs to be pushed out from the tip of the auger head 30 by about 1 m. With this, the penetration rod 52 slides along the inner surface of the cylindrical body 12, so that the penetration rod 52 and The rod 71a of the hydraulic cylinder 71 can slide satisfactorily in the vertical direction without rotation, twisting, buckling or the like.

  Note that the steady rest 74 only needs to have at least partly a shape whose outer shape follows the shape of the inner surface of the cylindrical body 13. There may be gaps. It is also preferable to provide a plurality of steady rests 74 at intervals in the vertical direction.

  Here, the penetrating rod 52 has a communication line 54a connected to the three-component sensor 54 (see FIG. 3) passing therethrough, and is configured in an elongated cylindrical shape. The static cone penetration test is a test for measuring the reaction force when the measuring cone 51 penetrates into the supporting ground to a predetermined depth, and a large reaction force corresponding to the ground supporting force acts on the penetration rod 52 at the time of the penetration. . In addition, the penetration rod 52 has a length necessary for the static cone penetration test, specifically, the thickness of the slime at the bottom of the pile hole and the distance at the distance from the tip of the auger head 30 to the bottom of the pile hole. It is necessary to have a length of about 1 m, which is the sum of the indentation amount and the length. For these reasons, the penetrating rod 52 needs to have a rigid structure that does not buckle even when an expected reaction force acts.

  Further, it is preferable that the penetration rod 52 is configured to be disassembled into a plurality of, for example, two to four rods. This facilitates the handling of the penetrating rod 52 when it is installed in the cylindrical bodies 11 and 12 or when it is disassembled for cleaning in STEP 7 described below. In particular, it is preferable that the penetration rod 52 be configured to be separable between a portion requiring or being housed in the solidified material press-fitting tube 53 or a portion requiring cleaning and another portion not requiring cleaning.

  In the vicinity of the upper end of the penetrating rod 52, an opening 52a formed of a through hole or a notch is formed. Through this opening 52a, the communication line 54a is exposed to the outside of the penetrating rod 52. The third cylindrical body 13 extends in the up-down direction via the formed opening 74a formed of a through hole or a notch. The portion of the penetration rod 52 located above the opening 74a does not need to be hollow.

  The opening 52a formed in the penetrating rod 52 is formed at a position where it does not enter the solidified material pressure feeding pipe 53 even when the rod 71a of the hydraulic cylinder 71 extends to the maximum. Thus, the risk of the solidified material flowing into the penetration rod 52 or the three-component sensor 54 located at the tip thereof through the opening 52a and the risk of the solidified material leaking out of the solidified material pumping tube 53 to the outside are reduced. Is achieved.

  However, when the opening 52a of the penetration rod 52 is provided above the steady rest 74, the opening 74a is not necessary. In this case, the steady rest 74 is formed at a position where the rod 71 a of the hydraulic cylinder 71 does not enter the solidified material pressure feeding pipe 53 even when the rod 71 a is extended to the maximum. When a plurality of the steady rests 74 are provided at intervals in the vertical direction, the lowermost steady rest 74 is located at a position where it does not enter the solidified material pressure feeding pipe 53 even when the rod 71a of the hydraulic cylinder 71 extends to the maximum. Formed.

  In order to allow the penetrating rod 52 and the rod 71a of the hydraulic cylinder 71 to slide satisfactorily in the vertical direction without buckling or the like, the outer diameter of the steady rest 74 is the diameter of the inner surface of the cylindrical body 12. It is preferable to make them approximately equal to.

  Further, it is preferable that the communication line 54a can expand and contract according to the expansion and contraction of the rod 71a of the hydraulic cylinder 71. Therefore, for example, although not shown, a reel having a winding function is interposed at any position of the communication line 54a, and the communication line 54a is adjusted by the winding and unwinding of the reel in accordance with the expansion and contraction of the rod 71a. It is preferable to be able to expand and contract.

  The steady rest 74 is also formed with an opening 74b formed of a through hole or a notch, through which the solidified material pumping tube 56 is inserted, and openings 74c, 74d through which the two fluid pipes 47, 48 are inserted.

  In FIG. 4, the steady rest 74 is provided on the distal end side of the opening 52a. However, the steady rest 74 may be provided on the upper end side of the opening 52a. However, in this case, the steady rest 74 needs to be provided at a position above the upper end of the solidified material pressure feeding pipe 53 even when the rod 71a of the hydraulic cylinder 71 is extended to the maximum extent. It does not enter the inside of the press fitting pipe 53.

  Referring to FIG. 4, the fourth-stage cylindrical body 14 has a built-in displacement gauge 81 for measuring the amount of movement of the rod 71 a of the hydraulic cylinder 71 and thus the amount of movement of the measuring cone 51. The displacement meter 81 is preferably of a wire type that measures displacement based on the number of rotations of a shaft of a reel (spool) that rotates by pulling out a wire whose end is fixed to the upper end of the rod 71a. This is because the humidity inside the auger rod 10 is high and the laser displacement meter is not suitable.

  When the displacement meter 81 is of a wire type, the tip of the wire is preferably fixed to the steady rest 74. When the displacement meter 81 is of a laser type, the laser target is preferably fixed to the steady rest 74.

  Although not shown, measurement-related equipment 82 such as an A / D converter for digitizing measurement data of the three-component sensor 54 and the displacement meter 81 is housed in the fourth-stage cylindrical body 14. . If there is no device to be installed at the center of the fourth-stage cylindrical body 14, the solidified material pumping tube 56 may be bent in the radial direction and provided at the center.

  Further, in the fourth cylindrical body 14, a solidified material pumping pipe 56, four fluid pipes 47, 48, 72, 73 (the fluid pipes 47 and 48 are not shown in FIG. 4) and a communication line 54a are provided. The inside is inserted vertically.

  The fifth stage, that is, the rearmost cylindrical body 15 constituting the auger rod 10 at the front end is provided with a male joint 10b connected to the female joint 20c at the rear end of the auger rod 20 connected to the upper end side. Have been. 6, the connecting portions 91a to 91d connected to the connecting portions at the ends of the four fluid pipes 47, 48, 72, and 73, respectively, and the end of the solidified material pumping pipe 56. There is a connecting portion 91e connected to the connecting portion of the portion, and these are automatically connected by being connected to the female joint 20c. Thus, the fluid pipes 47 and 48 are connected to fluid pipes (not shown), and the fluid pipes 72 and 73 are connected to fluid pipes 95 and 96 in the second and subsequent auger rods 20, respectively.

  Since the rear end of the fifth-stage cylindrical body 15 is the rear end of the first auger rod 10, the male joint 10b connected to the female joint 20c of the second auger rod 20 as described above. Is provided.

  The lower ends of the second and subsequent auger rods 20 are provided with connecting portions 92a to 92e (92b to 92d are not shown) connected to the connecting portions 91a to 91e, respectively. Here, the connection portions 92a to 92e are, for example, female connectors, respectively, and are automatically connected to the connection portions 91a to 91e formed of male connectors by connecting the male joints 10b and 20b and the female joint 20c. . Thereby, the fluid pipes (not shown) connected to the fluid pipes 47 and 48 and the fluid pipes 95 and 96 in the second and subsequent auger rods 20 are connected to the corresponding fluid pipes, respectively.

  Fluid pipes are connected to the connecting portions 92a to 92d, respectively, and these fluid pipes are arranged inside the auger rod 20. 7, the connecting portions 91a to 91d provided at the upper end of the auger rod 20 are connected to the upper ends of the fluid pipes. Further, a solidified material pressurizing pipe 93 is connected to the connecting portion 92e, and the solidified material pressurizing pipe 93 is disposed inside the auger rod 20. A connecting portion 91e provided at the upper end of the auger rod 20 is connected to the upper end of the solidified material pressure feeding pipe 93.

  A solidified material feed pipe 93 is connected to the center of the end surfaces of the male joint 10b of the auger rod 10 at the tip, the female joint 20c of the second auger rod 20, and the male joint 20b and the female joint 2c of the second and subsequent auger rods 20. The connection part 91e is arranged, and the connection parts 91a to 91d of the other fluid pipes 47, 48, 72, 73 are arranged on concentric circles radially away from the outer periphery.

  Further, a through hole 15c is formed in the upper peripheral wall of the fifth cylindrical body 15, and a communication line 94 connected to the measurement-related equipment 82 is formed through the through hole 15c. It is exposed to the outside.

  As shown in FIGS. 8 and 9, the second and subsequent auger rods 20 each have a through hole 20 d formed in a straight line at the base end of the spiral blade 20 a, and are inserted through the through hole 20 d. The protection tube 21 is fixed as described above. Each of the auger rods 20 has a communication line 22 inserted through the inside of the protective tube 21, and connectors 22 a are provided at both ends in the vertical direction. Accordingly, when connecting the auger rods 20 adjacent to each other, the communication lines 22 can be easily connected to each other by connecting the connectors 22a.

  Further, although not shown, when the auger rod 10 at the tip and the second auger rod 20 are connected, the communication lines 94 and 22 are easily connected by connecting the connector 94a and the connector 22a. can do. Further, it is preferable that the portions connected by the connectors 22a and 94a be covered by the protective cover 23.

  As shown in FIG. 10, the protection tube 21 and the outer periphery of the auger rod 20 are preferably fixed firmly by welding or the like. The communication line 22, the communication line 94, the connector 22a, and the connector 94a preferably have a waterproof function. Accordingly, even if muddy water or the like enters the protection cover and the protection pipe 21, the possibility of communication being interrupted can be reduced.

  The protective cover 23 has a shape capable of completely covering the communication line 22 and the communication line 94 exposed from the protective tube 21 and the connector 22a and the connector 94a, and the communication line 22 and the communication line 94 of the protective cover 23 and the connector 22a. It is preferable to provide a cushioning material such as a sponge on the surface in contact with the connector 94a. This makes it possible to reduce the possibility that the communication line 22, the communication line 94, the connector 22a, and the connector 94a are damaged by an impact even if digging or the like collides with the protective cover 23 due to excavation.

  It is preferable that the communication line 94 be protected from the through hole 15c to the outside to the connector 94a by the same protective tube 21 as the communication line 22. Although not shown, the connector 94a and the portion of the connector 22a exposed from the protection tube 21 are preferably protected by a protection member (not shown) until the auger rod 10 and the auger rod 20 or the auger rods 20 are connected.

  The various data measured by the three-component sensor 54 and the data of the displacement measured by the displacement meter 81 are transmitted to storage means such as an external computer provided in the earth auger driving device 120 via the communication lines 22 and 94. . Then, it is preferable that a load displacement curve is created by a computer or the like based on the data stored in the storage means, and this is displayed on a monitor or the like in real time. At this time, an operator or the like who has boarded the earth auger driving device 120 estimates the N value from various data, and if the N value is equal to or more than a predetermined value, determines that there is a supporting force.

  As described above, since the auger rod 10 at the distal end has a structure in which five separable cylindrical bodies 11 to 15 are connected, maintenance of equipment accommodated in any of these cylindrical bodies 11 to 15 can be performed. When performing operations such as replacement, it is possible to simplify the operation. For example, when the reel of the displacement gauge 81 is installed on the steady rest 74, or when the penetrating rod 52 is replaced due to bending or buckling, etc., the cylindrical bodies 11 to 15 which require work are replaced with other cylindrical bodies. The work can be performed separately from the cylindrical bodies 11 to 15, and further, the cylindrical bodies 11 to 15 can be exchanged.

  The auger rod 10 does not necessarily need to be formed of five cylindrical bodies 11 to 15, but may be formed of one to four or six or more cylindrical bodies. Further, the devices incorporated in each of the cylindrical bodies 11 to 15 are not limited to those described above.

  Hereinafter, in the pre-boring (cement milk) expanding root consolidation method, a method for confirming the ground supporting force according to the embodiment of the present invention using the above-described pile hole forming apparatus 100 will be described with reference to FIG.

  First, in a state where the enlarged head 42 is closed, an excavation hole is excavated to a depth less than the depth reaching the support layer as in the related art (STEP 1).

  The second auger rod 20 is connected to the first auger rod 10 as the depth of the excavation hole increases. This connection is performed by connecting the male joint 15c at the rear end of the first auger rod 10 and the female joint 20c at the front end of the second auger rod 20.

  As a result, the connecting portions 93a to 93d provided at the lower end of the fluid pipe provided inside the second auger rod 20 are connected to the connecting portions 92a to 92d provided at the upper end portion of the fifth-stage cylindrical body 15, respectively. You. Further, the protective member covering the connector 22a at the end of the communication line 22 exposed from the upper part of the fifth cylindrical body 15 and the connector 22a at the lower end of the communication line 22 provided on the second auger rod 20 was removed. Later, they are connected, and these connection locations are covered with a protective cover 23. In addition, a connecting portion 91e at the lower end of the solidified material pumping tube 93 provided inside the second auger rod 20 is connected to the connecting portion 92e at the upper end of the fifth-stage cylindrical body 15.

  Further, the third and subsequent auger rods 20 are connected to the second auger rod 20 as the depth of the excavation hole increases. This connection is performed by connecting the male joint 20b at the rear end of the second auger rod 20 and the female joint 20c at the front end of the third auger rod 20. As a result, the connecting portions 91a to 91d and 92a to 92d provided at the ends of the fluid pipes provided in the second and third auger rods 20 are connected to each other.

  In addition, a connector 91e at the lower end of the solidified material pumping pipe 93e provided on the third auger rod 20 is connected to a connector provided on the upper end of the solidified material pumping pipe 93e provided on the second auger rod 20. Furthermore, after removing a protective member covering the connector 22 a provided at the end of the communication line 22 provided on the second and third auger rods 20, the connection is made after removing the protective member. The connection of the fourth and subsequent auger rods 20 is performed in the same manner.

  The connection portions 91a to 91d at the upper ends of the fluid pipes provided on the last auger rod 20 are connected to the connection portions at the ends of pipes connected to a hydraulic device (not shown) provided in the auger driving device 120. Further, the connection portion 91e at the upper end of the solidified material pressure feeding pipe 93 provided on the last auger rod 20 is connected to the connection portion at the end of a tube connected to a solidified material tank (not shown) provided in the auger driving device 120.

  Next, in a state where the enlargement head 42 is expanded, an enlarged hole is formed to a depth at which the excavation hole is expected to reach the support layer (STEP 2). However, when the auger head 30 is rotationally driven, a resistance value serving as a predetermined rotational driving force may be estimated, and it may be confirmed that the estimated value of the resistance value exceeds a predetermined reference value. When the expansion head 42 is expanded, the hydraulic device is driven to flow the fluid into the oil chamber S1 via the first fluid pipe 44.

  While excavating the enlarged diameter hole, a solidified material such as cement milk is pumped through the solidified material pressurizing pipes 53 and 93, and is ejected through the injection holes 53a to consolidate the surrounding ground A (STEP 3). .

  Then, when the excavation hole is excavated to a predetermined depth assumed to be located in the support layer, excavation of the excavation hole is completed. Then, the enlargement head 42 is closed from this point until the earth auger 110 is pulled up.

  Thereafter, the earth auger 110 is lifted so that the tip of the auger head 30 is slightly separated from the tip of the drill hole. Then, in this suspended state, the measuring cone 51 is penetrated into the ground A by moving the penetrating rod 52 downward by a predetermined distance, and a static cone penetration test is performed to confirm the strength of the ground A ( (STEP 4). When the penetrating rod 52 is moved downward, the hydraulic cylinder 71 is driven to extend the rod 71a of the hydraulic cylinder 71.

  The test results, the amount of penetration of the measuring cone 51 and the reaction force from the tip of the measuring cone 51, are transmitted to an external computer or the like via a communication line.

  Then, after confirming that the tip of the excavation hole has reached the support layer, the penetration rod 52 is pulled up, and the measurement cone 51 is collected in the auger head 30 (STEP 5). Note that this STEP 5 may be performed after all the earth augers 110 have been pulled up.

  Thereafter, the earth auger 110 is pulled up, and the connection of the auger rods 10 and 20 is sequentially released (STEP 6). Disconnection of the auger rods 10 and 20 may be performed in a procedure reverse to the above-described connection.

  Finally, the auger rod 10 at the tip is disassembled into five cylindrical bodies 11 to 15, and the measuring cone 51, the solidified material feeding pipes 53 and 93, and the like are cleaned (STEP 7). As described above, since the auger rod 10 at the tip can be disassembled, it is possible to easily clean internal devices such as the measuring cone 51 and the solidified material pumping tube 53.

  It should be noted that the present invention is not limited to the pile hole forming apparatus 100 specifically described in the above-described embodiment and the method using the pile hole forming apparatus 100, but within the scope described in the claims. If so, it can be changed as appropriate.

  For example, hydraulic pressure is supplied to hydraulic paths such as fluid pipes 47 and 48 for supplying hydraulic pressure to a hydraulic cylinder 43 for expanding and closing the expanding head 42 and a hydraulic cylinder 71 for expanding and contracting the penetration rod 52. The above description has been made on the case where the hydraulic paths such as the fluid pipes 72 and 73 are separately and independently connected to the above-described hydraulic apparatus.

  However, the present invention is not limited to this, and these hydraulic paths may be connected to the same hydraulic device. In this case, by increasing the hydraulic pressure required to move the penetrating rod 52 downward as compared with the hydraulic pressure required to expand the enlarged head 42, the penetrating after the expanding head 42 is expanded (STEP 2). It becomes possible to move the use rod 52 downward (STEP 4). After that, as the hydraulic pressure decreases, the penetrating rod 52 returns upward (STEP 5), and then the enlarged head 42 closes.

  Also, the case where the present invention is applied to pre-boring has been described. However, the present invention is not limited to this, and may be applied to, for example, a middle digging method such as a middle digging method or a middle digging method. In addition, when the present invention is applied to the pre-boring method or the mid-drilling method, the pile hole forming apparatus 100 does not need to form the enlarged hole. It is not necessary to provide a hydraulic path such as fluid pipes 47 and 48 for supplying oil. In this case, the openings 74c and 74d of the steady rest 74 do not need to be present, and only the opening 72b through which the solidified material feeding pipe 56 is inserted and the opening 74a through which the communication line 54a is inserted need be present.

  In addition, the case where the tip of the solidified material pressure feeding pipe 53 is branched in the horizontal direction and the injection hole 53a is provided at the tip of the branched horizontal portion has been described. However, the present invention is not limited to this, and when used in the cement milk method or the like, in order to cause the solidified material to be ejected from the tip of the auger head 30, the solidified material pumping pipe 53 is made to penetrate to the tip of the auger head 30, and The solidified material may be ejected from the container. In this case, the sliding packing 55a becomes unnecessary.

  10: first auger rod, 10b: male joint, 11: first-stage cylindrical body (cylindrical body), 11a to 15a: spiral blade, 11b to 15b: flange, 11c: shaft, 11d: opening, 11e ... communicating holes, 12 ... second-stage cylindrical body (cylindrical body), 13 ... third-stage cylindrical body (first cylindrical body, cylindrical body), 14 ... fourth-stage cylindrical body (Second cylindrical body, cylindrical body), 15: fifth-stage cylindrical body (cylindrical body), 15c: through hole, 20: second and subsequent auger rods, 20a: spiral wing (spiral body) ), 20b: male joint, 20c: female joint, 20d: through hole, 21: protective tube, 22: communication line, 22a: connector, 23: protective cover, 30: auger head, 41: drill bit, 42: enlarged head 42a: magnifying wing, 42b: drill bit, 43: hydraulic cylinder, 43a: rod, 43b: hollow, 44: first fluid pipe (first fluid pipe), 45: second fluid pipe (first fluid pipe), 46a, 46b: connection part, 47: first fluid pipe (first fluid pipe), 48: second fluid pipe (first fluid pipe), 51: measuring cone, 52: rod for penetration (rod), 52a: opening, 53 ... Solidified material pressure feed pipe (tube), 53a: injection hole, 54: three-component sensor (resistance measuring means), 54a: communication line, 55: sealing means (sediment inflow prevention means), 55a: sliding packing, 56 ... Solidification material pressure feed pipe, 57a Connection part, 58 ... Upper sliding packing (solidification material inflow prevention means), 71 ... Hydraulic cylinder (penetration means, fluid means), 71a ... Rod, 72, 73 ... Fluid piping, 74 ... Runout Stop (movement restraint Means), 74a to 74d: Opening, 81: Displacement meter (displacement measuring means), 82: Measurement related equipment, 91: Connection, 91a to 91e: Connection, 92a to 92e: Connection, 93: Solidified material pressure feed pipe 94, communication line, 94a, connector, 94b, protective cover, 95, 96, fluid piping, 100, pile hole forming device, 110, earth auger, 120, earth auger driving device, 121, support, 122, anti-sway, A: ground, S1: upper oil chamber, S2: lower oil chamber.

Claims (7)

A pile-hole forming device that connects a plurality of auger rods in a vertical direction and rotationally drives the plurality of auger rods, thereby excavating the ground with an auger head provided at a tip end of the auger rod to form a pile hole. A method of confirming the bearing capacity of the ground using
The measuring cone connected to the lower end of the rod is pushed out of the auger head by moving a rod provided vertically movably in a tube extending vertically in the hollow part of the auger rod at the tip, to the outside of the auger head. Wherein the resistance when the measuring cone is penetrated is measured by a resistance measuring means positioned between the rod and the measuring cone. Method.   2. The method according to claim 1, wherein a vertical displacement of the rod is measured by a displacement measuring unit provided in the auger rod at the tip.   3. The pile hole forming device according to claim 1, wherein after the ground is excavated by the auger head to form the pile hole, a solidifying material is injected into the surrounding ground through the pipe. 4.   After injecting the solidifying material, expand the wings provided on the auger rod at the tip, and rotate the plurality of auger rods to expand the pile hole by the wings. The method of claim 3, wherein a cone is penetrated.   When rotationally driving the plurality of auger rods, a resistance value for obtaining a predetermined rotational driving force is estimated, and when the estimated value of the resistance value exceeds a predetermined reference value, or when the excavation depth is a predetermined depth, The method according to any one of claims 1 to 4, wherein the rotation driving is stopped when the rotation speed exceeds the threshold value. When connecting an auger rod to the upper end of the auger rod at the upper end,
A fluid is supplied to a mechanism for moving the rod downward, and a fluid pipe arranged in the auger rod to be connected is connected to a fluid pipe passing through the inside of the auger rod at the upper end,
The ground support force confirmation according to any one of claims 1 to 5, wherein a pipe arranged in the connected auger rod is connected to the pipe passing through the inside of the auger rod at the upper end. Method. When connecting an auger rod to the upper end of the auger rod at the upper end,
Removing the first protective cover provided at the end of the first communication line connected to the resistance measuring means for measuring the resistance when the measurement cone is penetrated;
Removing a second protective cover provided at an end of a second communication line disposed outside the auger head at the upper end,
After these, the end of the first communication line and the end of the second communication line are connected to each other, and the support force confirmation of the ground according to any one of claims 1 to 6, wherein Method.