JP7184276B2 - Pile hole forming device - Google Patents

Description

The present invention relates to a pile hole forming device.

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

When embedding a prefabricated concrete pile, it is necessary to insert the tip of the pile into a support layer having a bearing capacity of a predetermined level or more. In general, when excavating using an earth auger, by detecting the integral current value (the product of the current value considering the time required for excavation and the excavation time) in the device that drives the spiral auger, I'm checking if the tip of the auger has reached.

However, gravel taken in during excavation gets caught between the inner surface of the pile and the blades of the spiral auger, and sediment accumulates inside the pile, increasing peripheral friction. Judgment could occur. Therefore, in addition to the above determination, it is preferable to check whether the tip of the earth auger reaches 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 this lower rod is inserted into the ground by a fluid pressure cylinder is measured. , discloses measuring the strength of the ground.

Further, in Patent Document 2, a measurement cone connected to the tip of a pressing rod is provided in the auger head of a spiral auger, and the ground is measured by pressing this measurement cone against the ground and measuring the pressing force and the amount of press-in. 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. 3062478

However, in the technique disclosed in Patent Document 1, the resistance force when inserting the lower rod into the ground is obtained from the hydraulic pressure acting on the piston of the fluid pressure cylinder. An error may occur in the measured value due to the applied frictional force or the like.

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

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to provide a pile hole forming apparatus capable of improving the accuracy of ground strength measurement values.

The pile hole forming device of the present invention has a plurality of auger rods connected in the vertical direction, has an auger head at the tip of the auger rod at the tip, and rotates the plurality of auger rods to rotate the auger head. A pile hole forming device for excavating the ground and forming a pile hole with a pipe extending vertically in the hollow part of the auger rod at the tip, and a rod provided so as to be vertically movable in the auger rod at the tip a measuring cone connected to the lower end of the rod; and a measuring cone provided in the auger rod at the tip end, which moves downward to push the measuring cone out of the auger head and penetrate into the ground. and resistance measuring means positioned between the rod and the measuring cone for measuring the resistance when the measuring cone penetrates into the ground.

According to the pile hole forming device of the present invention, the measurement cone provided at the lower end of the auger rod portion at the tip can be penetrated into the ground by the penetrating means, and the resistance at that time can be measured by the resistance measuring means. is. From this, the bearing capacity of the ground can be confirmed by a normal static cone penetration test or a similar test. Furthermore, since the resistance measuring means is positioned between the rod and the measuring cone, the resistance can be measured without being affected by the weight of the rod itself, the frictional force acting on the rod, and the like. As a result, it is possible to improve the accuracy of ground strength measurements.

In the pile hole forming apparatus of the present invention, a displacement measuring means is provided in the auger rod at the tip and measures the vertical displacement of the rod .

Accordingly , since the displacement measuring means for measuring the vertical displacement of the rod is provided in the auger rod at the tip, the displacement of the rod can be measured by the measuring means provided outside the auger rod or inside the second and subsequent auger rods. Compared to the case of indirect measurement, the displacement of the rod can be measured with high accuracy, and it is possible to further improve the accuracy of the ground strength measurement value.

Moreover, in the pile hole forming apparatus of the present invention, it is preferable that the pipe is a first solidifying material pumping pipe for pumping the solidifying material.

In this case, the solidifying material pressure-feeding pipe for pressure-feeding the solidifying material and the pipe in which the rod can move up and down are shared, so that the structure can be simplified. However, the pile hole forming apparatus of the present invention can also be used for a construction method that does not use a solidification material, and in this case, there is no solidification material pumping pipe in the first place.

Further, in the pile hole forming apparatus of the present invention, the auger rod at the tip includes a first cylindrical body in which the penetrating means is provided, and a second cylindrical body in which the displacement measuring means is provided. is at least separable into

As a result , since the auger rod at the tip is configured by connecting at least two separable cylindrical bodies, maintenance and replacement of the penetrating means and the displacement measuring means housed in these cylindrical bodies can be eliminated. When doing so, it becomes possible to achieve simplification of workability.

Further, in the pile hole forming apparatus of the present invention, the penetrating means is a fluid cylinder in which the rod is fixed to a piston, and a first fluid pipe for supplying fluid to the fluid cylinder is in the auger rod at the tip A second solidifying material pressure-feeding pipe provided in the auger rod other than the auger rod at the tip end and connected to the first solidifying material pressure-feeding pipe, and a second fluid connected to the first fluid pipe A pipe is preferably provided.

In this case, since the second solidifying material pumping pipe and the second fluid pipe are provided inside the auger rod, excavation due to the rotation of the auger rod is more effective than when these pipes are exposed to the outside of the auger rod. do not get in the way when

Further, in the pile hole forming device of the present invention, the auger rod at the tip is formed by connecting a plurality of separable tubular bodies, and the adjacent tubular bodies are connected by flanges provided at the ends. It is preferable that the spiral body provided on the outer surface of each cylindrical body is continuously present between the flanges provided on each cylindrical body.

In this case, since the spiral body is continuously present on the outer surface of the cylindrical body except between the flanges, it is possible to improve the excavation efficiency by rotating the auger rod. In addition, it is preferable that the spiral body is also provided in the flange portion.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic side view of the pile hole forming apparatus which concerns on embodiment of this invention. The schematic side view which shows some auger rods. FIG. 4 is a schematic cross-sectional view showing a part of the first-stage cylindrical body; The schematic sectional drawing which shows a part of 1st auger rod. FIG. 5 is a schematic cross-sectional view taken along line VV of FIG. 4; FIG. 4 is a top view showing the male joint at the rear end of the first auger rod; FIG. 11 is a top view showing the male joint at the rear end of the second and subsequent auger rods; FIG. 2 is a schematic side view showing the vicinity of a connecting portion of a communication line; The figure which shows the state by which the protective tube is penetrated by the through-hole of a spiral blade. The figure which shows the state by which the protective tube is being fixed to the auger rod. 4 is a flow chart of a method for checking bearing capacity using a pile hole forming device;

A pile hole forming device 100 according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the pile hole forming apparatus 100 confirms that the tip of the earth auger 110 reaches the support layer when excavating the pile hole of the prefabricated pile using the earth auger 110. Equipped with a ground strength confirmation mechanism that allows

Here, a case where the pile hole forming device 100 is applied to a method of injecting a hardening material such as cement milk from the auger head 30 as a foot protection liquid among the embedded pile construction methods of the ready-made pile using the earth auger 110 will be described. . Specifically, it is a construction method such as a pre-boring method such as a cement milk construction method, a sub-digging construction method such as a sub-digging foot protection method, and a rotary construction method such as a rotary foot protection method.

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

The earth auger 110 is held by a steady rest 122 provided on a post 121 of the earth auger driving device 120 so as to be vertically movable, and is rotated by the auger head 30 which is guided by the post 121 and moved downward. , is pressed into the ground A.

As a result, the earth auger 110 is penetrated into the ground A, and an excavation hole is formed vertically downward. Then, by repeating the replacement of the auger head 30 that has reached the lower part of the support 121 to the upper part of the support 121 and the addition of the auger rod 20 to the earth auger 110 penetrated into the ground A, the design predetermined Deep drilling holes are formed.

The earth auger 110 is formed by connecting a plurality of auger rods 10 and 20 in the vertical direction, and the auger head 30 is provided at the tip (lower end) of the auger rod 10 at the forefront (bottom 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 helical blades (screws) 20a are fixed to the outer peripheral surface in order to send the 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 adjacently connected cylindrical bodies 11 to 15, respectively. Each of the cylindrical bodies 11-15 is provided with flanges 11b-15b at the ends thereof on the side of the connecting surface with the adjacent cylindrical bodies 11-15 for connection with the adjacent cylindrical bodies 11-15.

Although not shown in detail, through holes are formed in each of the flanges 11b to 15b, and the female threaded portion of the nut is screwed to the male threaded portion of the bolt while the bolt is inserted through the corresponding through hole. Thereby, the adjacent cylindrical bodies 11 to 15 are fixed. Male joints 10b and 20b are provided at the rear ends of the respective auger rods 10 and 20, and female joints 20c are provided at the leading ends of the second and subsequent auger rods 20, respectively. By connecting the male joints 10b, 20b and the female joint 20c, the adjacent auger rods 10, 20 are fixed.

Similarly to the auger rod 20, spiral blades 11a to 15a are fixed to the outer peripheral surfaces of the cylindrical bodies 11 to 15, respectively. The spiral blades 11a-15a are formed to be as continuous as possible. Here, the spiral wings 11a to 15a are formed up to the side surfaces of the flanges 11b to 15b, so that the spiral wings 11a to 15a are continuous. As a result, it becomes possible to improve the excavation efficiency by rotating the auger rod 10 .

An auger head 30 is provided at the tip (lower end) of the cylindrical body 11 at the first stage (the most advanced one). Specifically, a plurality of excavation bits 41 are attached to the tip of a helical 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 enlarged head 42 which can be opened and closed. The enlarged head 42 is composed of a plurality of, here, two enlarged wings 42a. Each enlarging wing 42a has an intermediate portion rotatably supported on a shaft 11c provided outside the cylindrical body 11, and a plurality of digging bits 42b attached to the tip portion. The enlarging wings 42 a of the enlarging head 42 are expanded and closed by a hydraulic cylinder 43 built in the cylindrical body 11 .

The other end of each expansion wing 42a is fitted into a recess 43b provided on the outer circumference of the rod 43a of the hydraulic cylinder 43. As shown in FIG. The hydraulic cylinder 43 has a vertically penetrating hole formed in its central portion, and has an elongated donut shape as a whole.

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

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

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

A penetrating rod 52 is slidably mounted within a tube 53 fixed to the cylindrical body 11 . Here, the penetrating rod 52 is provided in a solidifying material pressure-feeding pipe 53 for pressure-feeding a solidifying material such as cement milk provided in the central portion of the auger head 30 . The solidifying material pressure-feeding pipe 53 is provided so as to extend vertically in the central portion of the auger head 30 and pass through a through hole formed in the central portion of the hydraulic cylinder 43 .

The solidifying material pressure-feeding pipe 53 does not necessarily need to be provided at the center of the hydraulic cylinder 43. However, if it is provided at a position other than the center, it is difficult for the hydraulic pressure to act on the portion where the solidifying material pressure-feeding pipe 53 is installed, and the hydraulic cylinder 43 is pushed. It is not preferable because there is a possibility that bias may occur in the force applied. Note that the cross-sectional area of the solidifying material pressure-feeding pipe 53 in the first-stage cylindrical body 11 is larger than that of the solidifying material pressure-feeding pipe 56 in the second-stage cylindrical body 12 and beyond, which will be described later. It is preferable to be as large as the integral.

The tip of the solidifying material pressure-feeding pipe 53 reaches the opening 11d through the communication hole 11e. connected. The 3-component sensor 54 measures the tip resistance (qc) of the measurement cone 51, the circumferential friction (fs), and the pore water pressure (ud).

The solidifying material pressure-feeding pipe 53 branches horizontally above its tip, and a plurality of injection holes 53a are provided at the tips of these branched horizontal portions. Thus, the ejection holes 53a of the solidifying material pressure-feeding pipe 53 are provided in the peripheral portion above the tip of the auger head 30, and the solidifying material is horizontally ejected.

In addition, it is preferable to provide a sealing means 55 at the tip of the solidifying material pressure-feeding pipe 53 below the branching portion of the solidifying material pressure-feeding pipe 53 as much as possible so that earth and sand do not flow into the solidifying material pressure-feeding pipe 53 from the outside. The sealing means 55 is a sediment inflow preventing means for preventing sediment 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 in which it is pushed open from the inside by the protrusion of the measuring cone 51 and closed by a leaf spring or the like after the measuring cone 51 returns to its original position. It is a non-return valve (check valve). In addition to the sealing means 55, in order to bring the outer peripheral surface of the penetration rod 52 and the inner peripheral surface of the solidifying material pressure-feeding pipe 53 into close contact without a gap, the tip portion of the penetration rod 52 and the solidifying material pressure-feeding pipe 53 are separated from each other. A sliding packing 55a is mounted between the .

Even if such a sliding packing 55a exists, the three-component sensor 54 is positioned below the sliding packing 55a. As a result, the three-component sensor 54 can 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 it is necessary to eject the solidifying material downward as in the cement milk method, a sealing means 55 having such a weak sealing force as to be opened by the pressure of the pressure-fed solidifying material may be used.

Further, since the solidifying material pressure-feeding pipe 53 in the auger head 30 incorporates the penetrating rod 52, the area through which the solidifying material can pass is limited. Therefore, in order to secure the amount of pumped solidifying material, it is preferable to make the inner diameter larger than that of a normal one.

A penetration rod 52 is vertically inserted through the central portion of the second stage cylindrical body 12 . Furthermore, in the second-stage cylindrical body 12, first and second fluid pipes 47, 48 (second fluid The pipe 48 (not shown in FIG. 3) is connected via a connecting portion 46b and arranged inside.

A solidifying material pressure-feeding pipe 56 connected to the solidifying material pressure-feeding pipe 53 is also arranged inside the second stage cylindrical body 12 . The solidifying material pressure-feeding pipe 53 has a branched portion extending in the horizontal direction at the upper portion of the cylindrical body 11 in the first stage, and is shifted radially outward from the central portion of the upper end portion of the cylindrical body 11 . A part of it has a connecting portion 57a that is connected to a connecting portion 57b that is present at the end of the solidifying material pumping pipe 56 . As a result, in the second stage cylindrical body 12, the solidifying material pumping pipe 56 extends vertically at a portion away from the central portion.

Since the penetrating rod 52 moves up and down at the branch position of the solidifying material pressure-feeding pipe 53, the distal end of the solidifying material pressure-feeding pipe 53 is located above the horizontally extending portion of the solidifying material pressure-feeding pipe 53 so that the solidifying material does not leak out. is provided with an upper sliding packing 58 . The penetration 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 for pushing the penetration rod 52 downward. The rear end (upper end) of the penetration rod 52 is fixed to the tip (lower end) of the rod 71 a of the hydraulic cylinder 71 . Two fluid pipes 72 and 73 connected to the hydraulic cylinder 71 are also built in the third stage cylindrical body 13 .

Since the hydraulic cylinder 71 applies a load to the penetration rod 52 , it is preferable that the axial center of the hydraulic cylinder 71 coincides with the axial center of the third-stage cylindrical body 13 , like the penetration rod 52 . In this case, in the cylindrical body 13 of the third stage, the solidifying material pressure-feeding pipe 56 is arranged radially displaced from the axial center.

As the rod 71a of the hydraulic cylinder 71 extends, the penetration rod 52 moves downward, and the measurement cone 51 (see FIG. 3) fixed to the tip of the penetration rod 52 moves from the auger head 30. It protrudes to the outside below the tip. It is preferable that the mode of elongation such as the extension amount and elongation speed of the rod 71a of the hydraulic cylinder 71, that is, the mode of projection of the measurement cone 51, be the same as in the case of performing a penetration test in a normal static cone penetration test. . As a result, the relationship between the penetration amount of the measurement cone 51 and the bearing force in a normal static cone penetration test can be used as it is.

However, it may be different from the case of performing a penetration test in a normal static cone penetration test, and in this case, it is necessary to determine in advance the relationship between the penetration amount of the measurement cone 51 and the bearing capacity by experiment or the like in advance. .

It is preferable that the second-stage cylindrical body 12 incorporates a vibration stop 74 for preventing vibration, rotation, deformation, etc. of the penetration rod 52 . The steady rest 74 is fixed here 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 other portions of the penetrating rod 52 .

As shown in FIG. 5, the steady rest 74 has an outer shape that follows the shape of the inner surface of the cylindrical body 12, and here it is formed in a substantially disk shape. In the penetration test, it is necessary to push out the measuring cone 51 from the tip of the auger head 30 by about 1 m. The rod 71a of the hydraulic cylinder 71 can slide well in the vertical direction without rotation, twisting, or buckling.

It is sufficient for the steady rest 74 to have at least a part of its outer shape that follows the shape of the inner surface of the cylindrical body 13, and there is a slight gap between the outer surface and the inner surface of the cylindrical body 13. There may be gaps. It is also preferable to provide a plurality of anti-vibration braces 74 at intervals in the vertical direction.

The penetrating rod 52 here has a communication line 54a connected to a three-component sensor 54 (see FIG. 3) passing through the interior thereof, and is configured in an elongated cylindrical shape. The static cone penetration test is a test to measure the reaction force when the measurement cone 51 is penetrated into the supporting ground to a predetermined depth. . In addition, the penetration rod 52 has a length required for the static cone penetration test, specifically, the distance from the tip of the auger head 30 to the bottom of the pile hole, the thickness of the slime at the bottom of the pile hole, and the thickness of the slime at the time of the penetration test. , and the length of about 1 m is required, which is a long length. For these reasons, the penetration rod 52 must have a rigid structure that does not buckle even when the expected reaction force acts.

Moreover, it is preferable that the penetrating rod 52 is configured so as to be disassembled into a plurality of pieces, for example, two to four pieces. This facilitates 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, which will be described later. Preferably, the penetrating rod 52 is configured such that a portion requiring cleaning that is housed or can be housed in the solidifying material press-in tube 53 can be separated from other portions that do not require cleaning.

An opening 52a consisting of a through hole or a notch is formed in the vicinity of the upper end of the penetration rod 52, and the communication line 54a is exposed to the outside of the penetration rod 52 through this opening 52a. It extends vertically inside the third cylindrical body 13 through an opening 74a that is a formed through hole or notch. The portion of the penetration rod 52 located above the opening 74a need not be hollow.

The opening 52a formed in the penetration rod 52 is formed at a position where it does not enter the inside of the solidification material pumping pipe 53 even when the rod 71a of the hydraulic cylinder 71 is extended to the maximum extent. As a result, the risk of the solidifying material flowing into the penetrating rod 52 and the three-component sensor 54 located at the tip thereof through the opening 52a, and the risk of the solidifying material leaking out from the solidifying material pumping pipe 53 are reduced. is planned.

However, if 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 it does not enter the inside of the solidifying material pumping pipe 53 even when the rod 71a of the hydraulic cylinder 71 is extended to the maximum extent. In addition, when a plurality of the steady rests 74 are provided at intervals in the vertical direction, the lowest steady rest 74 is positioned so as not to enter the solidifying material pressure feeding pipe 53 even when the rod 71a of the hydraulic cylinder 71 is extended to the maximum. formed in

In addition, in order to allow the penetration rod 52 and the rod 71 a of the hydraulic cylinder 71 to be slidable in the vertical direction without buckling, the outer diameter of the steady rest 74 is equal to the diameter of the inner surface of the cylindrical body 12 . is preferably approximately equal to .

Furthermore, it is preferable that the communication line 54a be able to 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 wound and unwound by the reel so as to match the expansion and contraction of the rod 71a. It is preferable to make it stretchable.

The steady rest 74 is also formed with an opening 74b through which the solidifying material pumping pipe 56 is inserted and openings 74c and 74d through which the two fluid pipes 47 and 48 are inserted.

In addition, in FIG. 4, the steady rest 74 is provided on the tip side of the opening 52a. However, the anti-vibration 74 may be provided above the opening 52a. However, in this case, even when the rod 71a of the hydraulic cylinder 71 is fully extended, the steady rest 74 must be provided above the upper end of the solidifying material pressure-feeding pipe 53. It does not enter the inside of the press-in pipe 53 .

Referring to FIG. 4, the fourth stage cylindrical body 14 incorporates a displacement meter 81 for measuring the amount of movement of the rod 71a of the hydraulic cylinder 71 and the amount of movement of the measurement cone 51 as well. The displacement meter 81 is preferably of a wire type that measures the displacement based on the number of revolutions of the 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 gauge is not suitable.

If the displacement meter 81 is of wire type, the tip of the wire is preferably fixed to the steady rest 74 . Moreover, when the displacement meter 81 is of a laser type, it is preferable that the target of the laser be fixed to the steady rest 74 .

The fourth-stage cylindrical body 14 also accommodates measurement-related equipment 82 such as an A/D converter for digitizing the measurement data of the three-component sensor 54 and the displacement gauge 81, although not shown. . If there is no equipment to be installed in the central portion of the fourth stage cylindrical body 14, the solidifying material pumping pipe 56 may be bent in the radial direction and installed in the central portion.

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

The cylindrical body 15 at the rearmost end constituting the fifth stage, that is, the auger rod 10 at the tip 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 thereof. It is Also referring to FIG. 6, this male joint 10b includes connecting portions 91a to 91d connected to the connecting portions at the ends of the four fluid pipes 47, 48, 72, and 73, and the end of the solidifying material pumping pipe 56. A connecting portion 91e is provided to be connected to the connecting portion of the portion, and these are automatically connected by being connected to the female joint 20c. As a result, the fluid pipes 47 and 48 are connected to the fluid pipes (not shown), and the fluid pipes 72 and 73 are connected to the fluid pipes 95 and 96 in the auger rod 20 after the second one.

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

Connection portions 92a to 92e (92b to 92d are not shown) connected to the connection portions 91a to 91e are provided at the lower ends of the second and subsequent auger rods 20, respectively. Here, the connecting portions 92a to 92e are, for example, female connectors, respectively, and are automatically connected to the connecting portions 91a to 91e formed of male connectors by connecting the male joints 10b, 20b and the female joint 20c. . As a result, 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.

Fluid pipes are connected to the connecting portions 92 a to 92 d respectively, and these fluid pipes are arranged inside the auger rod 20 . Also referring to FIG. 7, connection portions 91a to 91d provided at the upper end portion of the auger rod 20 are connected to the upper ends of these fluid pipes. A solidifying material pressure-feeding pipe 93 is connected to the connecting portion 92 e , and the solidifying material pressure-feeding pipe 93 is arranged inside the auger rod 20 . A connecting portion 91 e provided at the upper end of the auger rod 20 is connected to the upper end of the solidifying material pressure-feeding pipe 93 .

A solidifying material pumping pipe 93 is connected at the center to the end faces of the male joint 10b of the tip auger rod 10, the female joint 20c of the second auger rod 20, and the male joint 20b and female joint 2c of the second and subsequent auger rods 20. A connecting portion 91e is arranged, and connecting portions 91a to 91d of the other fluid pipes 47, 48, 72, 73 are arranged on concentric circles radially separated from the outer periphery thereof.

Furthermore, a through hole 15c is formed in the upper peripheral wall of the fifth stage cylindrical body 15, and a communication line 94 connected to a measurement-related device 82 is connected to the cylindrical body 15 via this through hole 15c. exposed to the outside.

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

Furthermore, although not shown, when connecting the auger rod 10 at the tip and the second auger rod 20, the communication line 94 and the communication line 22 can be easily connected by connecting the connector 94a and the connector 22a. can do. Moreover, it is preferable to cover the portion connected by the connectors 22 a and 94 a with the protective cover 23 .

As shown in FIG. 10, the protection tube 21 and the outer circumference of the auger rod 20 are preferably fixed firmly by welding or the like. It is preferable that the communication line 22, the communication line 94, the connector 22a and the connector 94a have a waterproof function. As a result, even if muddy water or the like enters the protection cover and the protection tube 21, it is possible to reduce the risk of communication interruption.

In addition, the protective cover 23 has a shape capable of completely covering the communication lines 22 and 94 as well as the connectors 22a and 94a exposed from the protective tube 21. It is preferable to provide a cushioning material such as a sponge on the side that contacts the connector 94a. As a result, even if gravel or the like collides with the protective cover 23 during excavation, it is possible to reduce the risk of the communication line 22, the communication line 94, the connector 22a, and the connector 94a being damaged by the impact.

It is preferable that the communication line 94 is protected by the protective tube 21 similar to the communication line 22 from being exposed to the outside through the through hole 15c to the connector 94a. Also, the portions of the connector 94a and the connector 22a exposed from the protective tube 21 are preferably protected by a protective member (not shown) until the auger rod 10 and the auger rod 20 or the auger rods 20 are connected to each other.

Various data measured by the three-component sensor 54 and displacement amount data measured by the displacement meter 81 are transmitted to storage means such as an external computer provided in the earth auger driving device 120 or the like via the communication lines 22 and 94. . Then, based on the data stored in the storage means, it is preferable to create a load-displacement curve using a computer or the like and display it on a monitor or the like in real time. At this time, a worker or the like on the earth auger driving device 120 estimates the N value from various data, and if the N value is equal to or greater than a predetermined value, it is determined that the supporting force is present.

As described above, the auger rod 10 at the tip has a structure in which five separable cylindrical bodies 11 to 15 are connected. It is possible to simplify work when performing work such as replacement. For example, when installing a reel with a displacement gauge 81 on the steady rest 74, when replacing the penetrating rod 52 due to bending or buckling, etc., the cylindrical bodies 11 to 15 that require work are replaced with other The work can be performed separately from the cylindrical bodies 11 to 15, and furthermore, the cylindrical bodies 11 to 15 can be replaced.

The auger rod 10 does not necessarily have to consist of five cylindrical bodies 11 to 15, and may consist of one to four or six or more cylindrical bodies. Also, the devices built into the cylindrical bodies 11 to 15 are not limited to those described above.

Hereinafter, in the pre-boring (cement milk) expansion foot protection method, a method for confirming the bearing capacity using the pile hole forming apparatus 100 described above will be described with reference to FIG. 11 .

First, with the enlarged head 42 closed, an excavation hole is excavated to a depth below the support layer (STEP 1).

The second auger rod 20 is connected to the first auger rod 10 as the depth of the borehole 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 tip of the second auger rod 20. As shown in FIG.

As a result, the connection portions 93a to 93d provided at the lower end of the fluid pipe provided inside the second auger rod 20 are connected to the connection portions 92a to 92d provided at the upper end portion of the fifth-stage cylindrical body 15, respectively. be. Furthermore, the protective member covering the connector 22a at the tip of the communication line 22 exposed from the top of the fifth-stage cylindrical body 15 and the connector 22a at the lower end of the communication line 22 provided in the second auger rod 20 was removed. Later, both are connected and these connection points are covered with a protective cover 23 . Also, the connecting portion 91e at the lower end of the solidifying material pressure-feeding pipe 93 provided inside the second auger rod 20 is connected to the connecting portion 92e at the upper end of the cylindrical body 15 on the fifth stage.

Furthermore, the third and subsequent auger rods 20 are connected to the second auger rod 20 as the depth of the borehole 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 connection portions 91a to 91d and 92a to 92d provided at the ends of the fluid pipes of the second and third auger rods 20 are connected to each other.

Also, the connecting portion 91e at the lower end of the solidifying material pressure-feeding pipe 93e provided in the third auger rod 20 is connected to the connector provided at the upper end of the solidifying material pressure-feeding pipe 93e provided in the second auger rod 20. Furthermore, after removing the protective member covering the connector 22a provided at the end of the communication line 22 provided in the second and third auger rods 20, they are connected, respectively, and these connection points are covered with a protective cover 23. The fourth and subsequent auger rods 20 are connected in the same manner.

The connecting portions 91 a to 91 d at the upper ends of the fluid pipes provided in the final auger rod 20 are connected to the connecting portions at the ends of the pipes connected to the hydraulic system (not shown) provided in the auger drive device 120 . Furthermore, the connecting portion 91e at the upper end of the solidifying material pressure-feeding pipe 93 provided in the final auger rod 20 is connected to the connecting portion at the end of the pipe connected to the solidifying material tank (not shown) provided in the auger drive device 120.

Next, with the enlarged head 42 expanded, an enlarged diameter hole is formed to a depth that is assumed to reach the support layer (STEP 2). However, when the auger head 30 is rotationally driven, a resistance value that provides a predetermined rotational driving force may be estimated, and it may be confirmed that the estimated resistance value exceeds a predetermined reference value. When expanding the enlarged head 42, the fluid is caused to flow into the oil chamber S1 through the first fluid pipe 44 by driving the hydraulic device.

While excavating the enlarged diameter hole, a solidifying material such as cement milk is pressure-fed through the solidifying material pressure-feeding pipes 53 and 93, and jetted out through the injection hole 53a to perform foot protection of the surrounding ground A (STEP 3). .

When the drilling hole is drilled to a predetermined depth where the tip is assumed to be located in the support layer, the drilling of the drilling hole is finished. Then, the enlarged head 42 is closed from this point until the earth auger 110 is pulled up.

After that, the earth auger 110 is lifted so that the tip of the auger head 30 is slightly separated from the tip of the excavation hole. Then, in this lifted state, by moving the penetration rod 52 downward by a predetermined distance, the measurement cone 51 is penetrated into the ground A and a static cone penetration test is performed to confirm the strength of the ground A ( STEP4). When moving the penetration rod 52 downward, the rod 71a of the hydraulic cylinder 71 is extended by driving the hydraulic cylinder 71 .

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

After confirming that the tip of the excavation hole has reached the support layer, the penetration rod 52 is pulled up to retrieve the measurement cone 51 into the auger head 30 (STEP 5). Note that STEP 5 may be performed after pulling up all the earth augers 110 .

After that, the earth auger 110 is pulled up to sequentially disconnect the auger rods 10 and 20 (STEP 6). The disconnection of the auger rods 10, 20 may be performed in the reverse order of the connection described above.

Finally, the auger rod 10 at the tip is disassembled into five cylindrical bodies 11 to 15, and the measuring cone 51, the solidifying material pumping pipes 53, 93, etc. 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 solidifying material pumping pipe 53 .

In addition, the present invention is not limited to the pile hole forming device 100 specifically described in the above embodiment and the method using this pile hole forming device 100, but within the scope described in the claims. If necessary, 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 the hydraulic cylinder 43 for expanding and closing the expansion head 42 and to the hydraulic cylinder 71 for extending and contracting the penetration rod 52. A case has been described in which the hydraulic paths such as the fluid pipes 72 and 73 are connected to the hydraulic system independently and separately.

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

Also, the case of applying to pre-boring has been described. However, it is not limited to this, and for example, it may be applied to an inner excavation method such as an inner excavation foot protection method or an inner excavation expanded bottom foot protection method. In addition, when applied to a pre-boring foot protection method or a middle excavation bottom foot protection method that does not perform bottom expansion foot protection, there is no need to form an enlarged diameter hole. Hydraulic paths such as the fluid pipes 47 and 48 for supplying the fluid may not be provided.

A case has been described in which the tip of the solidifying 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. However, it is not limited to this, and when it is used for a cement milk construction method or the like, the solidifying material pressure-feeding pipe 53 is passed through the auger head 30 to the tip in order to eject the solidifying material from the tip of the auger head 30, and the tip of the auger head 30 is You may eject a solidification material from. In this case, the sliding packing 55a becomes unnecessary.

Reference Signs List 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 ...Communication hole 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 blade (helical 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... digging bit 42... enlargement head 42a... Expander 42b... Drilling bit 43... Hydraulic cylinder 43a... Rod 43b... Recess 44... First fluid line (first fluid line) 45... Second fluid line (first fluid line) fluid pipe), 46a, 46b... connection portion, 47... first fluid pipe (first fluid pipe), 48... second fluid pipe (first fluid pipe), 51... measurement cone, 52... for penetration Rod (rod) 52a... Opening 53... Solidifying material pumping pipe (pipe) 53a... Injection hole 54... Three-component sensor (resistance force measuring means) 54a... Communication line 55... Sealing means (prevention of sediment inflow) Means), 55a Sliding packing 56 Solidified material pumping pipe 57a Connecting part 58 Upper sliding packing (solidified material inflow prevention means) 71 Hydraulic cylinder (penetration means, fluid means) 71a Rod 72,73 Fluid piping 74 Steady rest 74a to 74d Opening 81 Displacement meter (displacement measuring means) 82 Measurement-related equipment 91 Connecting part 91a to 91e Connecting part 92a to 92e ... Connection part 93 ... Solidifying material pumping pipe 94 ... Communication line 94a ... Connector 94b ... Protective cover 95, 96 ... Fluid pipe 100 ... Pile hole forming device 110 ... Earth auger 120 ... Earth auger driving device , 121... Strut, 122... Steady rest, A... Ground, S1... Upper oil chamber, S2... Lower oil chamber.

Claims (4)

A plurality of auger rods are connected in the vertical direction, and an auger head is provided at the distal end of the auger rod. By rotating the plurality of auger rods, the ground is excavated by the auger head to form a pile hole. A pile hole forming device for forming,
a pipe extending vertically in the hollow portion of the tip auger rod;
a rod vertically movable within the tube ;
a measuring cone connected to the lower end of said rod;
a penetrating means provided in the auger rod at the distal end for moving the rod downward to push the measuring cone out of the auger head and penetrating into the ground;
a resistance measuring means positioned between the rod and the measurement cone for measuring resistance when the measurement cone penetrates into the ground ;
The auger rod at the tip comprises at least a first cylindrical body in which the penetrating means is provided and a second cylindrical body in which displacement measuring means for measuring vertical displacement of the rod is provided. A pile hole forming device, characterized in that it is separable . The pile hole forming apparatus according to claim 1, wherein the pipe is a first solidifying material pumping pipe for pumping the solidifying material. said penetrating means is a fluid cylinder with said rod fixed to a piston;
a first fluid pipe for supplying fluid to the fluid cylinder is provided in the distal auger rod;
A second solidifying material pressure-feeding pipe connected to the first solidifying material pressure-feeding pipe and a second fluid pipe connected to the first fluid pipe are provided in the auger rod other than the tip auger rod. 3. The pile hole forming device according to claim 2, wherein the pile hole forming device is . The auger rod at the tip is formed by connecting a plurality of separable cylindrical bodies, and the adjacent cylindrical bodies are connected by connecting flanges provided at the ends,
4. The spiral body provided on the outer surface of each cylindrical body continuously exists between the flanges provided on each cylindrical body. Pile hole forming device.

Images