JPH11222851A - Hollow pile for soil cement composite pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the agitation effect of soil cement and evenly agitate it in the depth direction by excavating a ground in advance by an excavating rod provided with an excavating and agitating blade widening the diameter wider than the outer diameter of a hollow pile and agitating uncured soil cement by an auxiliary agitating blade protruded to the outer periphery of the hollow pile. SOLUTION: A ground is excavated by an excavating rod 5 provided with an excavating and agitating blade widening the diameter wider than the outer diameter of a hollow pile 2 to insert the hollow pile 2 in soil cement that a solidifying material and the excavated soil is agitated and mixed together while rotating it, when constructing a composite pile made of the soil cement and the hollow pile 2. Auxiliary agitating blades 2a agitating uncured soil cement 1 by the rotation of the hollow pile 2 itself are protruded at every equal distance in the longitudinal direction of the hollow pipe 2 at the outer periphery of the hollow pile. The soil cement can be sufficiently agitated also by the auxiliary agitating blades 2a when the hollow pile is lowered together with the excavating rod.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a drilling rod which excavates the ground by enlarging the drilling diameter from the middle of a target depth.
The present invention relates to a hollow pile which is inserted into a soil cement in which a solidified material and excavated soil are agitated and mixed while rotating, and forms a composite pile together with the soil cement.

[0002]

2. Description of the Related Art Synthetic piles composed of soil cement and hollow piles such as steel pipe piles are used to construct the ground up to the support layer by a drilling rod having a drilling stirring blade whose diameter is larger than the outer diameter of the hollow pile. Stir and mix the solidified material and the excavated soil while excavating the soil, and then pull out the excavating rod and insert the hollow pile into the soil cement consisting of the excavated soil and the solidified material, or excavate and stir the blade from the lower end of the hollow pile. It is constructed by protruding a drilling rod having, excavating the ground in advance with the drilling rod, and lowering the drilling rod and the hollow pile while stirring and mixing.

In the former method, since the construction of the soil cement and the insertion of the hollow pile are independent, stirring and mixing can be performed even when the excavating rod is raised, but in the latter method, the excavated soil and the solidified material are stirred and mixed. Mixing is performed only by the drilling and stirring blades attached to the outer periphery of the drilling rod protruding from the lower end of the hollow pile. When drilling and stirring to the support layer and mixing are completed, the drilling rod is pulled up through the hollow pile. In addition, since stirring and mixing cannot be performed at the time of lifting, the stirring of the soil cement may not be performed sufficiently.

[0004] In view of the above background, the present invention proposes a hollow pile capable of sufficiently agitating soil cement even when the hollow pile is lowered together with a drilling rod.

[0005]

According to the present invention, an agitating auxiliary wing is protruded on the outer periphery of a hollow pile, so that a solidified material and excavated soil are agitated and mixed with an excavated rod while excavating the ground, and a soil before hardening is obtained. The cement is agitated again by the hollow pile to increase the efficiency of the agitation.

[0006] The agitating auxiliary wing is used to insert a hollow pile into the soil cement constructed by excavating the ground with a drill rod, stirring and mixing with a solidified material after pulling out the drill rod, and from the lower end of the hollow pile. In the method of protruding the excavation rod, excavating the ground in advance with the excavation rod, and lowering the excavation rod and the hollow pile while stirring and mixing, the excavation stirring blade of the excavation rod stirs, and the mixed soil cement is stirred again. Mix.

[0007] In the latter method as well, the soil cement constructed by the drilling rod preceding the hollow pile is again stirred by the stirring aileron of the hollow pile descending after passing through the drill rod.
By mixing, the stirring of the soil cement is performed evenly in the depth direction.

According to a second aspect of the present invention, the agitating auxiliary blade is evenly protruded in the circumferential direction of the hollow pile, and the distance from the center of the hollow pile to the tip of the agitating auxiliary blade is adjusted from the center of the rod to the tip of the excavating agitating blade. If the distance is approximately equal to the distance, the agitating auxiliary wing contacts the hole wall of the drilling, so that the hollow pile is located at the center of the soil cement, and acts to restrain the position of the hollow pile, When the hollow pile descends, its stability is secured, and after anchoring, the accuracy as a composite pile improves.

A drill rod is projected from the lower end of the hollow pile,
In the method of excavating the ground in advance with a drilling rod and lowering the drilling rod and hollow pile while stirring, the drilling and stirring blade performs excavation and stirring in a state where the diameter is larger than the outer diameter of the hollow pile, and the hollow pile is After anchoring in soil cement, drilling rods are pulled through the interior of the hollow pile,
The drilling agitator impinges on the lower end of the hollow pile and can be closed against the drilling rod.

On the other hand, when the excavating and stirring blade is structured so as to be opened and closed with the rotation of the excavating rod, the excavating and stirring blade is opened and closed by the resistance of soil received in a direction opposite to the rotation of the excavating rod when the excavating rod rotates. If the soil resistance is not sufficient, it may not be possible to securely close the drilling rod. If the drilling stirring blade is not closed, the drilling rod cannot be pulled up through the hollow pile.

According to the third aspect of the present invention, the excavation stirring blade of the excavating rod which rises while rotating relative to the hollow pile is provided on the outer periphery or inner periphery of the lower end of the hollow pile. By fixing the engagement member that engages in the direction and closes the excavation stirring blade, it is possible to securely close the excavation stirring blade even when soil resistance is not enough, and to take the drill rod into the hollow pile To

The excavating stirring blade is mounted on the excavating rod in such a manner that it can be rotated around the horizontal axis while being insulated from the rotation of the excavating rod. It is opened by the resistance of the soil when rotating, and closed similarly by the resistance of the soil when rotating in the opposite direction.

When the resistance of the soil is not enough when the excavating rod rises while rotating with respect to the hollow pile, and the excavating agitating blades cannot be completely closed, the excavating rod alone can be installed inside the hollow pile. However, due to the presence of the engaging member fixed to the lower end of the hollow pile, when the open drilling stirring blade engages with the engaging member in the circumferential direction of the drilling rod, the closing direction is closed. The drilling rod can be securely closed by receiving resistance from the hollow pile, so that the drilling rod can be taken into the hollow pile and pulled up through the hollow pile.

[0014] The engaging member also assists the opening of the excavating agitator by lowering the excavating rod while rotating with respect to the hollow pile and engaging the closed excavating agitator in the opening direction thereof, It also has the role of opening the door.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method for constructing a composite pile 3 consisting of soil cement 1 and a hollow pile 2, wherein a drilling rod 5 having a drilling stirring blade 4 whose diameter is larger than the outer diameter of the hollow pile 2 is ground. The hollow pile 2 is inserted into the soil cement 1 while stirring and mixing the solidified material and the excavated soil while excavating. The hollow pile 2 may be a steel pipe pile or a hollow concrete pile.

While excavating the ground to the support layer 10 with the bit 6 of the excavating rod 5 and the excavating stirring blade 4, the composite pile 3 is agitated and mixed with the solidified material and excavated soil. 16 or 17, by inserting the hollow pile 2 into the soil cement 1 made of the solidified material, or by protruding the drilling rod 5 from the lower end of the hollow pile 2 as shown in FIGS. It is constructed by lowering the excavating rod 5 and the hollow pile 2 while stirring and mixing the solidified material and the excavated soil.

An agitating auxiliary wing for agitating the unhardened soil cement 1 by rotating the hollow pile 2 itself on the outer periphery of the hollow pile 2.
2a is protruded. The agitating auxiliary wings 2a are spaced from each other in the longitudinal direction of the hollow pile 2 and are protruded at equal intervals in the circumferential direction.
FIGS. 1 and 2 show the auxiliary stirring blades 2a projecting in two directions on a plane, and the auxiliary stirring blades 2a in one direction are arranged at three places in the longitudinal direction, and the auxiliary stirring blades 2a in the orthogonal direction are arranged. Although a case where two positions are arranged in the length direction is shown, as shown in FIGS. 3 to 5, the arrangement in the projecting direction on the plane and the length direction can be freely determined.

When the hollow pile 2 is a steel pipe pile, the agitating auxiliary wing 2a is protruded by being welded to the outer peripheral surface of the steel pipe pile, or by attaching a ring-shaped component to which the agitating auxiliary wing 2a is welded, In the case of a concrete pile, it is protruded by welding to a steel material embedded in advance at the time of producing the concrete pile, or by attaching a ring-shaped part to which the agitating auxiliary wing 2a is welded after production.

The hollow pile 2 is connected to the same drive as the drive for rotating the drilling rod 5 or another drive, and is simply suspended and supported. When connected to the same drive, it rotates in the same direction as the drilling rod 5, and when connected to another drive, it rotates in the opposite direction to the drilling rod 5.
When the engaging member 2b is fixed to the lower end of the hollow pile 2 in a structure in which the excavating blade 4 opens and closes together with the rotation of the excavating rod 5 as described later, the hollow pile 2 is separated from the excavating rod 5 by another driving device. It rotates in the opposite direction or is suspended and supported, and does not rotate.

Since the hollow pile 2 descends in the borehole drilled by the drill rod 5, the agitating auxiliary wing 2 a is moved from the center of the hollow pile 2.
Is set to be equal to or less than the distance from the center of the excavating rod 5 to the tip of the excavating stirring blade 4, but as shown in FIG. 1 and FIG. When the distance to the tip of the excavating stirring blade 4 is made approximately equal,
The stirrer 2a has the function of regulating the position of the hollow pile 2 by contacting the hole wall of the drilling and positioning the hollow pile 2 itself at the center of the soil cement 1, so that the hollow pile 2 can be stabilized when descending. After the fixing, the accuracy as the composite pile 3 is secured.

FIG. 6 shows the hollow pile 2 used together with the excavating rod 5 having a structure in which the excavating and stirring blade 4 is opened and closed with the rotation of the excavating rod 5, and the engaging member 2b is fixed to the lower end. In FIG. 6 and thereafter, the auxiliary stirring blade 2a is omitted.

In this case, the excavating rod 5 has a structure in which a sleeve 7 to which the excavating and stirring blade 4 is rotatably connected is mounted in a state insulated from the rotation of the excavating rod 5 as shown in FIG. The wing 4 opens and closes with the rotation of the drilling rod 5 due to the resistance of soil received in the direction opposite to the rotation of the drilling rod 5.

The excavating and stirring blade 4 is rotatably connected to a plate 7b integrated with the outer periphery of the sleeve 7 by a pin 7c so as to be rotatable about an axis which is horizontal or inclined to some extent with respect to the horizontal. When the excavation rod 5 is rotated in the reverse direction, it is opened when the excavation rod 5 is rotated in the reverse direction, and is opened when the excavation rod 5 is rotated in the reverse direction.

An upper stopper 8 and a lower stopper 9 are provided on the outer periphery of the excavation rod 5 above and below the mounting position of the sleeve 7 to restrict the vertical movement of the sleeve 7 relative to the excavation rod 5 or to limit the movement to a certain amount or less. You. Upper stopper 8
Also, the lower stopper 9 serves to hold the excavating and stirring blade 4 from rotating downward when the excavating and stirring blade 4 is turned from a closed state to an opened state. And keeps it from closing.

As shown in FIG. 8, on the outer periphery of the excavating rod 5, a locked portion 5a is formed or projected so that the sleeve 7 is locked when the excavating and stirring blade 4 is closed and opened.
Of the excavating and stirring blades 4 when the excavating and stirring blades 4 are closed and opened.
A locking portion 7a for locking to the locked portion 5a is formed or protruded at a position corresponding to.

The sleeve 7 is insulated from the rotation of the excavating rod 5, so that the locking portion 7a is locked to the locked portion 5a in a direction opposite to the direction of rotation of the excavating rod 5 as shown in FIG. It rotates in the opposite direction to the excavation rod 5, and the locking portion 7a is locked by the locked portion 5a.
, And rotates together with the drilling rod 5 in the same direction as the drilling rod 5.

In the drawing, the drilling rod 5 is positive (clockwise)
When rotating, the locking portion 7a is locked to the locked portion 5a in the reverse rotation direction (counterclockwise), the excavation stirring blade 4 is opened, and when the drilling rod 5 rotates reversely, the locking portion 7a is rotated. Forms the locked part 5a and the locking part 7a so that the locking part 5a is locked in the forward rotation direction and the excavation stirring blade 4 is closed, but when the drilling rod 5 rotates in the reverse direction. The locked part 5a and the locking part are opened so that the drilling and stirring blade 4 is opened and the drilling and stirring blade 4 is closed when rotating forward.
7a may be formed.

In the state where the excavating stirring blade 4 is opened, FIG.
(c) As shown in FIG.
The excavation and stirring blade 4 is locked to the lower stopper 9 downward while being locked to the locked part 5a in the reverse rotation direction, and the excavation and stirring blade 4 can be locked to the upper stopper 8 upward. Keep open.

When the excavating and stirring blades 4 are closed, FIG.
As shown in (a), the excavation stirring blade 4 is detached from the lower stopper 9, and the locking portion 7a of the sleeve 7 is locked by the locked portion of the drilling rod 5.
By locking in the direction of forward rotation at 5a, the excavating and stirring blade 4 is kept closed.

The distance between the edge of the lower stopper 9 and the center of the excavating rod 5 gradually decreases from the open position to the closed position of the excavating agitating blade 4, and the excavating agitating blade 4 is closed at the closed position of the excavating agitating blade 4. With a shape that does not cause collision.

FIG. 8 (b) shows a state in which the excavating rod 5 starts to rotate forward. In this state, the excavating and stirring blades 4 receive the resistance of the soil in the direction of reverse rotation, so that the locking portion is formed. 7a is detached from the locked portion 5a, and the excavation stirring blade 4 is opened by being guided by the edge of the lower stopper 9 while rotating together with the sleeve 7.

FIG. 9 shows a state in which the engaging member 2b of the hollow pile 2 closes the opened excavating and stirring blade 4 in an auxiliary manner.

The engaging member 2b is fixed to the outer periphery or the inner periphery of the lower end of the hollow pile 2, and the excavating stirring blade 4 of the excavating rod 5 which rises while rotating relative to the hollow pile 2 is By engaging in the circumferential direction, the excavation stirring blade 4 that is not completely closed only by the rotation of the excavation rod 5 is closed.

In the drawing, at a certain level of the excavating rod 5, corresponding to the fact that two excavating agitating blades 4, 4 are on the same line, the engaging members 2b, 2b are placed at two symmetrical positions with respect to the center of the hollow pile 2. However, the engaging member 2b is fixed to at least one location to engage with the excavation stirring blade 4 by rotating the excavation rod 5 relative to the hollow pile 2 and close the same. Is enough. The engaging member 2b is fixed to the hollow pile 2 in the same manner as the above-mentioned protruding stirrer 2a.

In the case shown in the figure, since the excavation stirring blade 4 is closed by rotating forward with respect to the excavation rod 5, the hollow pile 2 is excavated as shown in FIGS. 9 (a) and 9 (b). By rotating forward with respect to the rod 5, the engaging member 2b is engaged with the opened excavating and stirring blade 4 in the closing direction, and (c)
The excavation stirring blade 4 is closed as shown in FIG.

The engaging member 2b closes the excavating and stirring blades 4 when the hollow pile 2 makes a forward rotation relative to the excavating rod 5, so that the hollow pile 2 is suspended and supported. When the hollow pile 2 is connected to a drive device different from the drill rod 5 by the reverse rotation of the drill 5, the hollow pile 2 rotates forward and the drill rod 5 rotates in the reverse direction.
Alternatively, the excavation rod 5 is stopped and the hollow pile 2 is rotated forward to close the excavation stirring blade 4.

FIG. 10 shows a state when the engaging member 2b assists the opening of the closed excavating and stirring blade 4 in a closed manner. Since the excavating agitating blade 4 is opened by receiving resistance in the reverse rotation direction, when the excavating rod 5 rotates forward and the excavating agitating blade 4 starts opening due to the resistance of the soil, as shown in FIG. When the hollow pile 2 rotates in the reverse direction with respect to the excavating rod 5, and the engaging member 2b engages with the excavating and stirring blade 4 in the reverse rotation direction, the excavating and stirring blade 4 is opened as shown in (c).

At this time, the engaging member 2b opens the excavation stirring blade 4 by rotating the excavating rod 5 in the normal direction and rotating the hollow pile 2 in the reverse direction relative to the excavating rod 5.
When the hollow pile 2 is suspended and supported, and the excavation rod 5 rotates forward when it is stationary, the hollow pile 2 is
When it is connected to another drive device, the excavation stirring blade 4 is opened by the forward rotation of the excavation rod 5 and the reverse rotation of the hollow pile 2.

FIGS. 11 to 15 show a state in which the excavating rod 5 protrudes from the lower end of the hollow pile 2 and the excavating stirring blade 4 is open.
The state until the excavation rod 5 is taken into the hollow pile 2 is shown. At this time, the excavation rod 5 rotates reversely as described above, or rises with respect to the hollow pile 2 while remaining stationary. In each figure, (a) is a plan view and (b) is an elevation view.

As shown in FIG. 12, the hollow pile 2 rotates forward and descends with respect to the drill rod 5, or the drill rod 5 rises with respect to the hollow pile 2, thereby causing
The engaging member 2b engages with the excavating and stirring blade 4 to close the excavating and stirring blade 4 as shown in FIG. As shown in FIG. 14 and FIG. 15, the excavation rod 5 is taken into the hollow pile 2, and the entire excavation stirring blade 4 is closed.

FIG. 16 shows a construction procedure of a method of constructing the composite pile 3 using the excavating rod 5 shown in FIG. In FIG. 16, the engaging member 2b is omitted. FIG. 16 shows an example where the intermediate layer and the support layer 10 are not hard ground.

The excavating rod 5 protrudes from the lower end of the hollow pile 2 as shown in FIG. 16- (a), and is connected to the lower end of the excavating rod 5 in one direction, that is, in the case shown in FIG. The ground is excavated by the bit 6 and the open excavating and stirring blade 4, and at the same time, the solidified material and excavated soil discharged from the ground through the excavating rod 5 or supplied into the ground through a pipe or the like are removed by the excavating and stirring blade 4. Stir and mix.

Until immediately before the bit 6 reaches the target support layer 10, a low-concentration (poorly mixed) peripheral fixative is used as a solidifying material. As shown in FIG. The solidified material is switched to a high-concentration (rich mixture) root compaction solution, and while excavating the support layer 10, stirring and mixing, the pile tip 11
To build.

Before the hardening of the soil cement 1 made of excavated soil and solidified material at the pile tip 11, the excavating rod 5 and the hollow pile 2 are once pulled up as shown in (c). At this time, the excavating rod 5 is pulled up while rotating in the reverse direction relative to the hollow pile 2, and the excavating and stirring blades 4 are sequentially closed by the engaging members 2b of the hollow pile 2, and as shown in FIG. 2 is taken in. (d) corresponds to the state shown in FIG.

Thereafter, as shown in FIG. 5E, the hollow pile 2 is pressed into the pile tip 11 and the excavating rod 5 is pulled up to complete the construction.

FIG. 17 shows a construction procedure for constructing the composite pile 3 when the hard layer 12 is present in the intermediate layer before reaching the support layer 10. In this case, a claw protrudes from the lower end of the hollow pile 2.

Until the bit 6 reaches the hard layer 12, (a)
When the bit 6 reaches the hard layer 12 as shown in FIG. 16, the drilling rod 5 is raised while rotating in the reverse direction as shown in FIG. The stirring blade 4 is closed and stored in the hollow pile 2.

In this state, as shown in FIG.
And the hollow pile 2 are rotated, and the ground is excavated until the bit 6 and the claw of the hollow pile 2 penetrate the hard layer 12. The rotation of the hollow pile 2 may be in the same direction as the rotation of the excavation rod 5 or in the opposite direction. (b) and (c) correspond to the state shown in FIG.

After the penetration of the hard layer 12, the excavating rod 5 and the hollow pile 2 are pulled up to the upper layer of the hard layer 12 as shown in (d), and the excavating rod 5 is again raised from the lower end of the hollow pile 2 as in (a). At the same time, the excavating rod 4 is opened by rotating the excavating rod 5 forward, and the solidified material and the excavated soil are excavated while the ground is excavated to the support layer 10 by the bit 6 and the excavating agitating blade 4 as shown in FIG. Are stirred and mixed by the excavating stirring blade 4. The opening of the excavation stirring blade 4 in (d) is supplemented by the engaging member 2b of the hollow pile 2.

Thereafter, the steps are performed according to the steps shown in FIGS. 16 (c) to (e).

When the support layer 10 is the hard layer 12, FIG.
-It is constructed in the same way as the steps shown in (a) to (e).

[0052]

According to the present invention, an auxiliary agitating blade is protruded from the outer periphery of a hollow pile which is inserted while rotating into a soil cement constructed by an excavating rod having an excavating agitating blade whose diameter is larger than the outer diameter of the hollow pile. In addition to increasing the cement stirring efficiency, the soil cement can be stirred uniformly in the depth direction.

According to a second aspect of the present invention, the stirring impeller is evenly protruded in the circumferential direction of the hollow pile, and the distance from the center of the hollow pile to the tip of the stirring impeller is equal to the distance from the center of the rod to the tip of the drilling stirring impeller. In order to make the same degree, the stability of the hollow pile at the time of descent is secured, and the accuracy as a composite pile is improved after anchoring.

According to a third aspect of the present invention, when used together with a drilling rod having a drilling agitating blade which opens and closes with the rotation of the drilling rod and whose diameter is larger than the outer diameter of the hollow pile at the time of opening, the lower end of the hollow pile is connected to the hollow pile. The drilling agitating blade of the drilling rod, which rises while rotating relatively, engages in the circumferential direction of the drilling rod and closes the open drilling agitating blade to fix the engaging member that closes the drilling agitating blade. Even when the soil resistance is insufficient, the drilling agitator can be reliably closed and the drilling rod can be pulled into the hollow pile.

The engaging member also has a function of rotating the drilling rod while descending with respect to the hollow pile, and opening the drilling stirring blade by engaging the closed drilling stirring blade in the opening direction. In addition, the closed excavation stirring blade can be reliably opened.

[Brief description of the drawings]

FIG. 1 (a) is a plan view showing a hollow pile according to claim 1, and FIG.
(A) is an elevational view of (a).

FIG. 2 is an elevation view showing the relationship between soil cement and hollow piles.

3A is a plan view showing a modification of the hollow pile shown in FIG. 1, and FIG. 3B is an elevation view of FIG.

4A is a plan view showing a modification of the hollow pile shown in FIG. 1, and FIG. 4B is an elevation view of FIG.

5 (a) is a plan view showing a modified example of the hollow pile shown in FIG. 1, and FIG. 5 (b) is an elevation view of FIG.

FIG. 6 is an elevational view showing a hollow pile and a drill rod according to the third embodiment.

FIG. 7 is an elevation view showing a drilling rod used in the third embodiment.

8 (a) to 8 (c) are plan views showing the relationship between the excavation stirring blade and the excavation rod shown in FIG. 7 from a closed state to an open state.

9 (a) to 9 (c) are plan views showing the relationship between the excavating and stirring blades from the open state to the closed state and the hollow pile according to the third aspect.

10 (a) to 10 (c) are plan views showing the relationship between the excavating and stirring blades and the hollow pile of claim 3 from the closed state to the open state.

FIG. 11 (a) is a plan view showing the relationship between the hollow pile and the drilling rod according to claim 3, when the drilling rod is projected,
(b) is an elevation view of (a).

FIG. 12 (a) is a plan view showing a state in which the hollow pile starts to descend while rotating forward with respect to the drilling rod, and FIG.
It is an elevation view of (a).

FIG. 13 (a) is a plan view showing a state where a hollow pile closes an excavating and stirring blade, and FIG. 13 (b) is an elevation view of FIG. 13 (a).

14 (a) is a plan view showing a state where the hollow pile relatively descends from FIG. 13, and FIG. 14 (b) is an elevation view of FIG. 13 (a).

FIG. 15 (a) is a plan view showing a state when a drill rod is taken into a hollow pile, and FIG. 15 (b) is an elevation view of FIG. 15 (a).

16 (a) to (e) are elevation views showing a construction procedure for constructing a composite pile.

17 (a) to 17 (e) are elevation views showing other construction procedures of the composite pile construction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Soil cement, 2 ... Hollow pile, 2a ... Agitating auxiliary wing, 2b ... Engagement member, 3 ... Synthetic pile, 4 ... Drilling agitating blade, 5 ... Drilling rod, 5a ... Stop part, 6 ... bit, 7 ... sleeve, 7a ... locking part, 7b ... plate
7c: Pin, 8: Upper stopper, 9: Lower stopper, 10: Support layer, 11: Tip of pile, 12: Hard layer.

Claims (3)

[Claims] 1. A method for constructing a composite pile comprising soil cement and a hollow pile, wherein a drilling rod having a drilling stirring blade having a diameter larger than the outer diameter of the hollow pile excavates the ground, while solidifying material and excavated soil are removed. A hollow pile for a soil cement composite pile, which is a hollow pile that is inserted into a stirred and mixed soil cement while rotating, and on the outer periphery of which is provided with a stirring agitating wing that stirs the uncured soil cement. 2. The agitating auxiliary blade is evenly provided in the circumferential direction of the hollow pile, and the distance from the center of the hollow pile to the tip of the agitating auxiliary blade is equal to the distance from the center of the drilling rod to the tip of the excavating agitating blade. The hollow pile for a soil cement composite pile according to claim 1, wherein 3. A hollow pile, which is opened and closed with the rotation of the drill rod and has a drilling agitating blade whose diameter is larger than the outer diameter of the hollow pile at the time of opening, is provided on the outer periphery or inner periphery of the lower end of the hollow pile. The excavating stirring blade of the excavating rod that rises while rotating relatively to the outer peripheral surface engages in the circumferential direction of the excavating rod, and an engaging member that closes the excavating stirring blade is fixed. A hollow pile for a soil cement composite pile according to the above.