JP5674189B2 - Pile hole drilling head - Google Patents

Description

  The present invention relates to an excavation head for an excavation rod for excavating a pile hole as pile foundation work in the fields of construction, civil engineering, and the like, and a pile hole excavation method using the excavation head.

  In a drilling head in which a spiral blade is formed on the head body connected to the drilling rod and a drilling blade is fixed to the lower end of the spiral blade, the drilling blade generally has a flat plate shape with a shallow blade edge (drilling angle). The cutting edge of the excavating blade was arranged at the same depth (substantially horizontal position) with respect to the ground (Patent Document 1). While rotating the excavation head, all the tips (cutting edges) of the excavation blades were grounded almost simultaneously, excavating the bottom of the pile hole. In this case, the distance from the lower end of the head body to the tip of the excavation blade, that is, the length of the excavation blade, is usually set to about 10 cm when the excavation diameter is about 50 to 80 cm. In the case of this excavation head, in order to excavate with an enlarged diameter, an expanded bottom excavation blade that is movable and protrudes outward is attached.

  Moreover, the device which improves excavation efficiency by using the excavation blade which changes with soil properties, improving the excavation property of the ground was also made | formed (nonpatent literature 1).

  In addition, a drilling head in which a drilling arm is swingably attached to the drilling head body has been proposed (Patent Document 2). In this excavation head, when there is gravel, the fixed excavation blade and the auxiliary excavation blade are set to a length twice the maximum size of the gravel.

Reality 7-50468 JP-A-2005-307496 Japan Concrete Pile Construction Technology Association, “Construction management of ready-made concrete piles”, 5th edition, Japan Concrete Pile Construction Technology Association, June 2008, page 274

  In the case of excavation heads having spiral blades among conventional excavation heads (PTL 1, Non-Patent Document 1) in pile hole excavation in the ground mixed with large particles such as cobblestones, When there was a large particle size, cobblestones entangled with the fixed excavation blade, and the fixed excavation blade did not come into contact with the ground, which could make it impossible to excavate.

  Also, in the case of a drilling head having a drilling arm among conventional drilling heads (Patent Document 2), normally, if there is gravel or the like, the excavation arm causes the gravel or the like to approach the center of the pile hole, The pile hole was excavated with the auxiliary excavating blade and the fixed excavating blade of the excavating arm while it was positioned between the excavating arms and rolled at the center of the bottom of the pile hole (around the center of the head body). However, if the maximum particle size of gravel or cobblestone exceeds the distance between the excavating blades, the gravel or cobblestone will be caught or entangled between the excavating blades, and the tip of the excavating blade will be placed on the bottom of the pile hole (excavation surface). In some cases, excavation was not possible.

  Therefore, when the excavation speed is reduced due to foreign matter being caught between the excavating blades, the excavation speed may decrease, or the excavation head may be temporarily lifted to remove the foreign matter and resume excavation. In any case, the pile hole excavation time was excessive, and the required process could be significantly delayed.

Therefore, in the present invention, the length of the fixed excavation blade of the excavation head ( same as the height ; the same applies hereinafter) H ₁ and the interval W ₁ with respect to the maximum particle diameter D ₀ found in the ground investigation in advance, Since the length H ₁ and the interval W ₂ , the horizontal distance L ₁ between the tip of the arm excavating blade and the tip of the fixed excavating blade, and the vertical distance h ₁ were determined, the above problems were solved.

That is, the present invention is a pile hole excavation characterized in that an excavation arm is swingably attached to a horizontal shaft provided in a head body having a connecting portion connected to a lower end of an excavation rod, and is configured as follows. Head.
(a) downwardly to the lower surface of the head body, a fixed excavating blade length H _1, to a plurality fixed at predetermined intervals W1.
(b) the lower end of the excavating arm, downward, arm digging edge length H _2, to a plurality fixed at predetermined intervals W2.
(c) The arm excavating blade is disposed obliquely with respect to the vertical so that the tip faces outward, and the distance between the tip of the arm excavating blade and the tip of the fixed excavating blade is the horizontal axis direction. distance is referred to as _{L 1.}
(d) from the lower end of the fixed digging edge, the distance to the tip of the arm digging edge and h _1.
(e) With respect to the maximum particle size D ₀ of foreign matter such as gravel in the ground that has been found by soil investigation of the ground to be excavated, the following “a. condition” and / or Satisfies “a. Condition”.
A. Fixed excavating blade length H ₁ and spacing W ₁ > maximum particle size D ₀
A. Arm drilling blade length H ₂ and spacing W ₂ > maximum particle size D ₀

In addition, in the above, with respect to the maximum particle size D ₀ of foreign matter such as gravel in the ground, which has been found by the soil investigation of the ground to be excavated, the “a. Condition” and “ The pile hole excavation head according to claim 1, wherein the condition “a.” Is satisfied and the following condition is satisfied.
C. Horizontal distance L ₁ > maximum particle diameter D ₀ between the tip of the arm excavating blade and the tip of the fixed excavating blade
D. Vertical distance h ₁ > maximum particle diameter D ₀ between the arm excavation blade tip and the fixed excavation blade tip

Moreover, another invention is a pile hole excavation method characterized by excavating a pile hole in the following procedures (1) to (5).
(1) The maximum particle size D ₀ of foreign matter such as gravel in the ground, which has been found by soil investigation of the ground to be excavated, is determined in advance.
(2) A pile hole excavation head characterized in that the excavation arm is swingably attached to a horizontal shaft provided in a head body having a coupling portion coupled to the lower end of the excavation rod, and is configured as follows. prepare.
(a) downwardly to the lower surface of the head body, a fixed excavating blade length H _1, to a plurality fixed at predetermined intervals W1.
(b) the lower end of the excavating arm, downward, arm digging edge length H _2, to a plurality fixed at predetermined intervals W2.
(c) The arm excavating blade is disposed obliquely with respect to the vertical so that the tip faces outward, and the distance between the tip of the arm excavating blade and the tip of the fixed excavating blade is the horizontal axis direction. distance is referred to as _{L 1.}
(d) from the lower end of the fixed digging edge, the distance to the tip of the arm digging edge and h _1.
(3) The excavation head of (2) has the following “a. Condition” and / or “b.” In a state where the excavation rod does not rotate with respect to the maximum particle diameter D ₀ of the foreign matter such as gravel . so as to satisfy the conditions ", to configure.
A. Fixed excavating blade length H ₁ and interval W ₁ > maximum particle size D ₀ of foreign matter such as gravel
A. Arm drilling blade length H ₂ and spacing W ₂ > maximum particle size D ₀ of foreign matter such as gravel
(4) Excavating the ground from the ground while rotating the selected excavation head.
(5) When foreign matter such as gravel is generated during excavation, the foreign matter such as gravel is moved between the fixed excavating blades, between the arm excavating blades, or between the fixed excavating blade and the while passing between the arms digging edge and drilling before Symbol drilling head.

Moreover, another invention is a pile hole excavation method characterized by excavating a pile hole in the following procedures (1) to (5).
(1) The maximum particle size D ₀ of foreign matter such as gravel in the ground, which has been found by soil investigation of the ground to be excavated, is determined in advance.
(2) A pile hole excavation head characterized in that the excavation arm is swingably attached to a horizontal shaft provided in a head body having a coupling portion coupled to the lower end of the excavation rod, and is configured as follows. prepare.
(a) downwardly to the lower surface of the head body, a fixed excavating blade length H _1, to a plurality fixed at predetermined intervals W1.
(b) the lower end of the excavating arm, downward, arm digging edge length H _2, to a plurality fixed at predetermined intervals W2.
(c) The arm excavating blade is disposed obliquely with respect to the vertical so that the tip faces outward, and the distance between the tip of the arm excavating blade and the tip of the fixed excavating blade is the horizontal axis direction. distance is referred to as _{L 1.}
(d) from the lower end of the fixed digging edge, the distance to the tip of the arm digging edge and h _1.
(3) The excavation head of (2) has the following “a. Condition” to “d. Condition” in a state where the excavation rod does not rotate with respect to the maximum particle size D ₀ of the foreign matter such as gravel . so as to satisfy ", to configure.
A. Fixed excavating blade length H ₁ and interval W ₁ > maximum particle size D ₀ of foreign matter such as gravel
A. Arm drilling blade length H ₂ and spacing W ₂ > maximum particle size D ₀ of foreign matter such as gravel
C. Distance L _{1 in} the horizontal direction between the tip of the arm excavating blade and the tip of the fixed excavating blade L ₁ > maximum particle diameter D ₀ of foreign matter such as gravel
D. Distance h _{1 in} vertical direction between tip of arm excavating blade and tip of fixed excavating blade h ₁ > maximum particle diameter D ₀ of foreign matter such as gravel
(4) Excavating the ground from the ground while rotating the selected excavation head.
(5) in the middle excavation, if the foreign matter such as gravel outer diameter D ₀ occurs, foreign matter such as the gravel, while between the arm digging edge, (5) drilling middle, foreign matter such as the gravel In the case of the occurrence of foreign matter such as gravel, while passing between the fixed excavation blades, between the arm excavation blades, or between the fixed excavation blade and the arm excavation blade, Drill with a drilling head.

According to the present invention, the length H ₁ and the interval W ₁ of the fixed excavation head of the excavation head, the arm excavation are determined according to the maximum diameter D ₀ of foreign matter such as gravel on the excavation ground by conducting a preliminary ground (soil) survey in advance. Since the blade length H ₁ and interval W ₂ , the horizontal distance L ₁ between the tip of the arm excavating blade and the tip of the fixed excavating blade, and the vertical distance h ₁ are determined, even if foreign matter such as gravel appears, Since it is not pinched in the excavation head, the excavation work can be performed as planned without being interrupted.

Further, by setting the interval W ₁ between the fixed excavation blades and the interval W ₂ between the arm excavation blades to be equal to or larger than the maximum particle size D ₀ in the excavation ground, even if a foreign material having the maximum particle size D ₀ is generated, It can pass between excavation blades without being pinched between both excavation blades. Therefore, the tip of the excavation blade can reach the bottom surface (excavation surface) of the pile hole, and there is an effect that the excavation can be continued and the pile hole can be constructed without reducing the excavation efficiency.

  Therefore, there is no delay in the drilling of the pile hole, and the construction period of the pile foundation is ensured and can be stabilized.

FIG. 1 is a non-rotating state of an excavation head according to an embodiment of the present invention, in which (a) is a front view and (b) is a bottom view. FIG. 2 is also a right side view. FIGS. 3A and 3B show a small-diameter excavation state of the excavation head according to the embodiment of the present invention, in which FIG. 3A is a front view and FIG. 3B is a bottom view. FIG. 4 is a right side view of the same. FIGS. 5A and 5B are a large-diameter excavation state of the excavation head according to the embodiment of the present invention, in which FIG. 5A is a front view and FIG. 5B is a bottom view. FIG. 6 is also a right side view.

  It is a pile hole excavation head 30 which is connected to the lower end of the excavation rod 40 and used for excavation of the pile hole (FIGS. 1 and 2). The pile hole excavation head 30 is configured by excavating arms 15 and 15 swingably attached to horizontal shafts 12 and 12 provided on a head body 1 having a connecting portion shaft 5 connected to an excavation rod 40. Further, the following (a) to (e) are configured.

(a) downwardly to the lower surface 6a of the head body 1, a fixed digging edge 10, 10 of a height H _1, a plurality fixed at predetermined intervals W _1.
(b) a lower end 10a of the excavation arm 15, downwards, the arm digging edge 24, 24 of a height _{H 2,} to a plurality fixed at predetermined intervals _{W 2.}
(c) The arm excavation blade 24 is disposed obliquely so that the tip 25 faces outward with respect to the vertical. In this case, the tip 25 of the arm digging edge 24, the distance between the tip 11 of the fixed digging edge 10, the distance of the horizontal axis 12 direction L _1.
(d) A vertical distance from the lower end 11 of the fixed excavating blade 10 to the tip 25 of the arm excavating blade 24 is defined as h ₁ .
(e) to the pre-ground survey, foreign matter such as gravel maximum diameter D ₀ (typically, D ₀ is about 2Cm～10cm) into the formation should investigate that exists. In this case, according to the maximum diameter D ₀ , the dimensions of the height H ₁ and the interval W ₁ , the height H ₂ and the interval W ₂ , the horizontal distance L ₁ , and the vertical distance h ₁ are as follows in relation to D ₀ Adjust as follows.
A. Height H ₁ and interval W ₁ > D _{0 of} fixed excavation blade 11
A. The height H ₂ and the interval W ₂ > D _{0 of the} arm excavating blade 24
C. Horizontal distance L ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
D. Vertical distance h ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
Here, condition a. Condition a. Must satisfy one or both of the conditions. D. It is desirable to satisfy the conditions.

Embodiments of the present invention will be described with reference to the drawings.

1. Example of excavation head 30

(1) Head The main body 1 is connected to the upper end 2a of the square columnar base 2 with a connecting shaft portion 5 to be connected to the excavation rod so that the base 2 and the shaft coincide with each other, and continues to the lower end of the base portion 2. Thus, a flat bulging portion 6 is formed.
The four side surfaces of the base 2 are defined as first side surfaces 3 and 3a parallel to each other and second side surfaces 4 and 4a parallel to each other. In the bulging portion 6, the surfaces continuous with the first side surfaces 3 and 3 a of the base portion 2 are defined as first side surfaces 7 and 7 a, continuous with the second side surfaces 4 and 4 a of the base portion 2, and the first side surfaces 7 and 7 a Adjacent (opposite) surfaces are second side surfaces 8 and 8a. That is, the second side surfaces 8 and 8 a are located in the bulging direction of the bulging portion 6. Therefore, the 1st side surfaces 7 and 7 of the bulging part 6 become a flat surface, and the bulging part 6 bulges in a horizontal direction, and is formed so that the width | variety of a flat surface may become large. Further, the lower surface 6a of the bulging portion 6 is formed such that the central portion is linear and both end portions 6b and 6b are inclined upward. A discharge port 13 for discharging cement milk or the like from the ground into the pile hole is provided in the central portion of the lower surface 6a of the bulging portion 6, and a length is provided on both sides of the discharge port 13 on the lower surface 6a of the bulging portion 6. The fixed excavating blades 10 and 10 of L ₁ are attached with their tips 11 and 11 facing downward and at a distance W ₁ .
The tips 11 and 11 of the fixed excavation blades 10 and 10 are aligned on a substantially straight line. Further, the fixed excavation blades 10 and 10 are formed so as to be inclined with the distal end 11 facing the first side surface 7a side, which is positioned on the second side surface 8 side from the discharge port 13. Further, fixed excavation blades 10 and 10 positioned on the second side surface 8a side with respect to the discharge port 13 are formed to be inclined with the tip 11 directed toward the first side surface 7 side.
Further, the base 2 and the bulging portion 6 are arranged such that the first side surfaces 3 and 3a and the first side surfaces 7 and 7a approach each other downward (the widths of the second side surfaces 4 and 4a and the second side surfaces 8 and 8a are The dimensions are set so that they shrink.

(2) Head Horizontal axes 12, 12 are formed on the first side surfaces 3, 3 a of the base 2 of the main body 1. The horizontal shaft 12 can be either an integral shaft or a divided shaft as long as the first side surfaces 3 and 3a have the same axis.
The base end portion 20 of the excavating arm 15 is attached to the horizontal shafts 12 and 12 so as to be swingable. Further, since the horizontal shaft 12 only needs to be an axis that can rotate the excavating arm 15, the horizontal shaft 12 may be provided on the excavating arm 15 and a bearing may be provided on the head body 1 (not shown).

(3) The excavation arm 15 has a surface on the head body 1 side as an inner surface 16a and a side opposite to the inner surface 16a as an outer surface 16.
The base end portion 20 of the excavating arm 15 is formed with a large diameter around the horizontal axis 12, the intermediate portion 21 has a small width, and a wide end portion 22 is formed. Further, both the excavating arms 15 and 15 are formed so that the inner surfaces 16a and 16a of the base end portions 20 and 20 are parallel to each other, and the intermediate portions 21 and 21 are arranged such that the inner surface 16a and the inner surface 16a approach each other downward. The outer surface 16 is bent so that it approaches. Therefore, the lower end of the intermediate portion 21 is formed in the closest shape, and the tip portions 22 and 22 are formed so that the inner surface 16a and the inner surface 16a move away from each other and the outer surface 16 and the outer surface 16 move away from each other.
Accordingly, the distal end portions 22 of the excavation arms 15 and 15 are formed so as to open outward, and the excavation blades 24 and 24 extend outward toward the lower end of the excavation arms 15 and 15 so as to be continuous in the opening direction. 24 is projected.

The distal end 25 of the arm excavating blade 24 faces outward, and the outer surface of the arm excavating blade is attached to be inclined at an angle θ1 with respect to the vertical (FIG. 2). Further, the length from the lower end 15a of the excavation arm 15 to the tip 25 of the arm digging edge 24 and _{L 2,} the distance between the arm digging edge 24, 24 and _{W 2} (Figure 1 (a)).

Further, the vertical distance between the tip 11 of the fixed excavating blade 10 and the tip 25 of the arm excavating blade 24 is set to h ₁ (FIG. 2). In this case, since the cutting edges 25 and 25 of the arm excavation blade 24 are arranged obliquely in front view, the distance between the distal end 25 of the arm excavation blade 24 located at the uppermost position and the fixed excavation blade 10 is indicated.
Further, the tip 11 of the fixed digging edge 10, horizontal distance between the tip 25 of the arm digging edge 24 (distance of the horizontal axis 12 direction) and L ₁ (FIG. 2). In this case, since the cutting edges 25 and 25 of the arm excavating blade 24 are arranged obliquely in a bottom view, the fixed excavating blade 10 located near the discharge port 13 and the arm excavating blade closest to the fixed excavating blade 10 are arranged. 24 refers to the horizontal distance.
Moreover, the surface (surface in the same direction as the 2nd side surface 4 of the base 2) which adjoins the inner surface 16a and the outer surface 16 of the excavation arms 15 and 15 is made into the one side surface 17, and the other side (the same as the 1st side surface 4a of the base 2). The surface in the direction) is the other side surface 18. One side surface 17 is a side surface facing the front surface when swinging in the forward rotation, and the other side surface 18 is a side surface facing the rear surface side when swinging in the forward rotation.

(4) Moreover, the operation protrusion 26 which protrudes upwards is formed in the upper end of the base 20 of an excavation rod. When the excavating arms 15 and 15 are rotated in the forward direction and rocked to excavate a large diameter, the operation protrusion 26 comes into contact with the stopper 32 for restricting the maximum rocking and the first side surfaces 3 and 3a of the base 2 of the head body 1 are used. Respectively. Further, at this time, stoppers 33, 33 against which the other side surface 18 of the intermediate portion of the excavating arms 15, 15 hits are protruded from the bulging portion 6.
Further, plate-like stirring plates 34, 34 are obliquely projected on the second surfaces 4, 4 a of the base 2 of the head body 1 (surfaces where the horizontal shafts 12, 12 are not provided).

The excavation head 30 of this invention is comprised as mentioned above (FIG. 1, FIG. 2). In this excavation head 30, the following values are set to be larger than the diameter D ₀ of the gravel having the maximum particle diameter that was found when the ground survey was conducted in advance.
A. Height H ₁ and interval W _{1 of the} fixed excavation blade 10
A. The height H ₂ and the interval W _{2 of the} arm excavating blade 24
C. The horizontal distance L ₁ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
D. Vertical distance h ₁ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10

2. Pile hole construction method

(1) Conduct a ground survey in advance at or around the construction site. In this case, in addition to the normal boring survey, whether or not there is a foreign substance such as gravel, and if present, the diameter of the foreign substance is investigated. Then, it sets the maximum diameter of the stand foreign matter as D _0. In this case, it is desirable to investigate the presence of foreign matter in all the strata, but at least “thick strata (for example, thicker than about 2 m)” and / or “stratum considered to be difficult to drill (N value is Investigate with relatively large layers, in particular N values ≧ 20) ”.

(2) In the excavation head 30 having the above-described configuration,
A. Height H ₁ and interval W ₁ > D _{0 of} fixed excavation blade 11
A. The height H ₂ and the interval W ₂ > D _{0 of the} arm excavating blade 24
C. Horizontal distance L ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
D. Vertical distance h ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
The excavation head 30 is prepared so that the dimensions of the height H ₁ and the interval W ₁ , the height H ₂ and the interval W ₂ , the horizontal distance h ₁ , and the vertical distance h ₁ are adjusted.
For example, when D ₀ = 10 cm,
A. Height of fixed excavating blade 11 H ₁ = 15 cm, interval W ₁ = 15 cm
A. Height of arm excavation blade 24 H ₂ = 15 cm, interval W ₂ = 15 cm
C. Horizontal distance L ₁ = 15 cm between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
D. Vertical distance h ₁ = 15 cm between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
And the set excavation head 30 is used.

(3) Subsequently, similarly to normal pile hole excavation, the connecting shaft portion 5 of the excavating rod 30 is inserted and connected to the lower end portion of the excavating rod 40, and the excavating rod 40 is rotated forward. Per tip on the ground arm digging edge 10 of the digging arm 15 (FIG. 1 (a), FIG. 2) to drill following, to begin drilling, open excavation arm 15 with earth pressure, the pile hole shaft at a predetermined diameter DD ₁ (FIG. 3 (a), FIG. 4). In this case, the arm excavating blade 24 cuts the periphery and side wall of the bottom of the pile hole, and the fixed excavating blade 10 cuts the vicinity of the center of the bottom of the pile hole. Therefore, even when a foreign matter of about diameter D ₀ from the formation (such as gravel) is present, between the fixed digging edge 10, 10, between the arms digging edge 24, 24 or fixed digging edge 10 and arm digging edge, Pile hole excavation can be performed efficiently without being sandwiched between 24.
Further, the swing angle of the excavating arms 15 and 15 in this state is maintained by a stopper (not shown) provided on the head main body 1 or the excavating arm 15.

(4) Subsequently, following excavation of the shaft portion of the pile hole, the excavation arm 15 is swung until the excavation arm 15 and the operation projection 26 come into contact with the stoppers 32 and 33 in the same manner. To do. In this state, a pile hole widening portion is excavated with a predetermined diameter DD ₂ (FIGS. 5A and 5B, FIG. 6). In this case, similarly, the arm excavation blade 24 cuts the periphery and the side wall of the bottom of the pile hole, and the fixed excavation blade 10 cuts the vicinity of the center of the bottom of the pile hole. Therefore, even when a foreign matter of about diameter D ₀ from the formation is present, between the fixed digging edge 10, 10, between the arms digging edge 24 and 24, or between the fixed digging edge 10 and arm digging edge 24 Pile hole drilling can be performed efficiently without being pinched.

(5) Moreover, when a foreign substance replaces pile hole fillings, such as excavation mud, with the injected cement milk, the tip part 22 of the excavation arms 15 and 15, the stirring plate 34, Through 34, it is raised upward and discharged to the ground. The remaining foreign matter is kneaded with the injected cement milk to become soil cement.

(6) Although the excavation rod 40 is rotated forward to perform small-diameter excavation and large-diameter excavation, the excavation arm 15 and 15 can be swung to the other side by reverse rotation and excavation can be performed (not shown). Absent).

3. Other examples

In the above embodiment,
A. Height H ₁ and interval W ₁ > D _{0 of} fixed excavation blade 11
A. The height H ₂ and the interval W ₂ > D _{0 of the} arm excavating blade 24
C. Horizontal distance L ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
D. Vertical distance h ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
However, at least a. Or a. It is necessary to satisfy at least one of the following.
A. Height H ₁ and interval W ₁ > D _{0 of} fixed excavation blade 11
A. The height H ₂ and the interval W ₂ > D _{0 of the} arm excavating blade 24
In particular,
C. Horizontal distance L ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
D. Vertical distance h ₁ > D ₀ between the tip 25 of the arm excavating blade 24 and the tip 11 of the fixed excavating blade 10
Is an important condition immediately after the start of excavation, but when excavation is advanced, the excavation arm 24 swings, and “the distal end 25 of the arm excavation blade 24 and the distal end 11 of the fixed excavation blade 10” are relative to each other. Since it leaves | separates, the said conditions will be in the state always satisfied.

DESCRIPTION OF SYMBOLS 1 Head main body 2 Base 2a of a head main body Upper end 3 of a base 3, 3a 1st side surface 4 of a base, 4a 2nd side surface 5 of a base 5 Connection shaft part 6 Head bulging part 6a Swelling lower surface 6b Both ends 7 and 7a on the lower surface First side surfaces 8 and 8a of the bulging portion Second side surface 10 of the bulging portion Fixed excavation blade 11 Tip 12 of the fixed excavation blade Horizontal axis 13 Discharge port 15 Excavation arm 15a Lower end 16 of the excavation arm Excavation Arm outer surface 16a Drilling arm inner surface 17 One side surface 18 of the drilling arm 32, 33 Stopper 34 Stirring plate 40 Drilling rod

Claims (4)

A pile hole excavation head characterized in that an excavation arm is swingably attached to a horizontal shaft provided in a head body having a coupling portion coupled to a lower end of an excavation rod, and is configured as follows.
(a) downwardly to the lower surface of the head body, a fixed excavating blade length H _1, to a plurality fixed at predetermined intervals W1.
(b) the lower end of the excavating arm, downward, arm digging edge length H _2, to a plurality fixed at predetermined intervals W2.
(c) The arm excavating blade is disposed obliquely with respect to the vertical so that the tip faces outward, and the distance between the tip of the arm excavating blade and the tip of the fixed excavating blade is the horizontal axis direction. distance is referred to as _{L 1.}
(d) from the lower end of the fixed digging edge, the distance to the tip of the arm digging edge and h _1.
(e) With respect to the maximum particle size D ₀ of foreign matter such as gravel in the ground that has been found by soil investigation of the ground to be excavated, the following “a. condition” and / or Satisfies “a. Condition”.
A. Fixed excavating blade length H ₁ and spacing W ₁ > maximum particle size D ₀
A. Arm drilling blade length H ₂ and spacing W ₂ > maximum particle size D ₀ The maximum particle diameter D ₀ of the foreign matter such as gravel in Ground found by soil survey of the ground drilling plan, in a state in which the drill rod does not rotate, the "A. Conditions" and "a. The condition" The pile hole excavation head according to claim 1, wherein the following conditions are satisfied.
C. Horizontal distance L ₁ > maximum particle diameter D ₀ between the tip of the arm excavating blade and the tip of the fixed excavating blade
D. Vertical distance h ₁ > maximum particle diameter D ₀ between the arm excavation blade tip and the fixed excavation blade tip Pile hole excavation method characterized by excavating a pile hole in the following procedures (1) to (5).
(1) The maximum particle size D ₀ of foreign matter such as gravel in the ground, which has been found by soil investigation of the ground to be excavated, is determined in advance.
(2) A pile hole excavation head characterized in that the excavation arm is swingably attached to a horizontal shaft provided in a head body having a coupling portion coupled to the lower end of the excavation rod, and is configured as follows. prepare.
(a) downwardly to the lower surface of the head body, a fixed excavating blade length H _1, to a plurality fixed at predetermined intervals W1.
(b) the lower end of the excavating arm, downward, arm digging edge length H _2, to a plurality fixed at predetermined intervals W2.
(c) The arm excavating blade is disposed obliquely with respect to the vertical so that the tip faces outward, and the distance between the tip of the arm excavating blade and the tip of the fixed excavating blade is the horizontal axis direction. distance is referred to as _{L 1.}
(d) from the lower end of the fixed digging edge, the distance to the tip of the arm digging edge and h _1.
(3) The excavation head of (2) has the following “a. Condition” and / or “b.” In a state where the excavation rod does not rotate with respect to the maximum particle diameter D ₀ of the foreign matter such as gravel . so as to satisfy the conditions ", to configure.
A. Fixed excavating blade length H ₁ and interval W ₁ > maximum particle size D ₀ of foreign matter such as gravel
A. Arm drilling blade length H ₂ and spacing W ₂ > maximum particle size D ₀ of foreign matter such as gravel
(4) Excavating the ground from the ground while rotating the selected excavation head.
(5) When foreign matter such as gravel is generated during excavation, the foreign matter such as gravel is moved between the fixed excavating blades, between the arm excavating blades, or between the fixed excavating blade and the while passing between the arms digging edge and drilling before Symbol drilling head. Pile hole excavation method characterized by excavating a pile hole in the following procedures (1) to (5).
(1) The maximum particle size D ₀ of foreign matter such as gravel in the ground, which has been found by soil investigation of the ground to be excavated, is determined in advance.
(2) A pile hole excavation head characterized in that the excavation arm is swingably attached to a horizontal shaft provided in a head body having a coupling portion coupled to the lower end of the excavation rod, and is configured as follows. prepare.
(a) downwardly to the lower surface of the head body, a fixed excavating blade length H _1, to a plurality fixed at predetermined intervals W1.
(b) the lower end of the excavating arm, downward, arm digging edge length H _2, to a plurality fixed at predetermined intervals W2.
(c) The arm excavating blade is disposed obliquely with respect to the vertical so that the tip faces outward, and the distance between the tip of the arm excavating blade and the tip of the fixed excavating blade is the horizontal axis direction. distance is referred to as _{L 1.}
(d) from the lower end of the fixed digging edge, the distance to the tip of the arm digging edge and h _1.
(3) The excavation head of (2) has the following “a. Condition” to “d. Condition” in a state where the excavation rod does not rotate with respect to the maximum particle size D ₀ of the foreign matter such as gravel . so as to satisfy ", to configure.
A. Fixed excavating blade length H ₁ and interval W ₁ > maximum particle size D ₀ of foreign matter such as gravel
A. Arm drilling blade length H ₂ and spacing W ₂ > maximum particle size D ₀ of foreign matter such as gravel
C. Distance L _{1 in} the horizontal direction between the tip of the arm excavating blade and the tip of the fixed excavating blade L ₁ > maximum particle diameter D ₀ of foreign matter such as gravel
D. Distance h _{1 in} vertical direction between tip of arm excavating blade and tip of fixed excavating blade h ₁ > maximum particle diameter D ₀ of foreign matter such as gravel
(4) Excavating the ground from the ground while rotating the selected excavation head.
(5) in the middle excavation, if the foreign matter such as gravel outer diameter D ₀ occurs, foreign matter such as the gravel, while between the arm digging edge, (5) drilling middle, foreign matter such as the gravel In the case of the occurrence of foreign matter such as gravel, while passing between the fixed excavation blades, between the arm excavation blades, or between the fixed excavation blade and the arm excavation blade, Drill with a drilling head.

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