JPH0133606B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a construction method for pouring on-site construction piles and a construction pile driving device for use in the method, and is applicable to the construction of support piles for structures, etc. do.

[Conventional technology]

The conventional pile construction method is a non-polluting method that does not produce vibrations, noise, or waste such as bentonite mud, and excavates to a specified depth with an earth auger, and injects mortar from the tip of the bit.
Widely used methods include the PIP method, in which the inner pipe used as the injection pipe is pulled out to create a mortar pile, and the MIP method, in which soil cement piles are created by mixing the earth and sand at the pile placement location with cement milk spouted from the tip of the bit. Are known.

[Problem that the invention seeks to solve]

However, the conventional cast-on-site pile construction method has a problem in that it is difficult to perform construction management as with ready-made piles. In other words, in the case of ready-made piles, the strength of the piles can be confirmed in advance, and in the case of using a pile driver, it is relatively easy to calculate the estimated bearing capacity of the ground and piles from the relationship between the driving force and the amount of sinking. However, with the conventional pile pile construction method, the only way to estimate it is based on the amount of settlement, etc. through post-construction surveys, and the actual strength of the pile itself cannot be obtained through mixing tests on the ground, so it is not reliable. Scarce;
In some cases, it is being used wastefully.

Furthermore, in connection with the difficulty in construction management, it is not possible to check the injection status of the hardening material such as mortar, which may result in insufficient injection or outflow of the hardening material in some parts.

The construction method and device of the present invention were invented to solve these problems, and when constructing piles, the drawing speed of the drilling device is adjusted so that a predetermined downward pressing force is applied when hardening material is injected. By controlling this, the purpose is to ensure the injection of hardening material, to enable sufficient construction management during the construction of the reclamation piles, and to obtain highly reliable reclamation piles.

[Means for solving problems]

In the pile construction method of this invention, first, a casing 11 serving as an outer pipe and an inner pipe 12 serving as an injection pipe are
While rotating as a unit, the leader mast 30
It will be sunk to a specified depth along the Note that a method is usually adopted in which a digging bit 18 is provided at the tip of the inner pipe 12 and earth and sand is pushed laterally by the head 17. Then, at the time of drawing out, a hardening material 2 such as mortar is press-fitted from the tip of the inner tube 12 to create a hardening material 3 due to hardening of the hardening material 2.

Regarding the injection of the hardening material 2 during this pulling out, while continuously recording and measuring the amount of hardening material injected and the injection pressure, etc., the rising speed of the inner tube 12 and the casing 11 is adjusted to counteract the injection pressure of the hardening material 2. The injection is performed while applying a predetermined downward pressing force. Note that there are cases where the casing 11 is left underground and only the inner pipe 12 is pulled up. In addition, an enlarged portion 3' may be provided to increase the support force at the tip of the pile 3 or the frictional force on the circumferential surface. With this construction management, it is also possible to create the enlarged portion 3' at an arbitrary position.

In addition, the construction pile driving device according to the present invention supports the casing 11 and the inner pipe 12 by a support frame 20 provided at the upper part, and can run this support frame 20 at any speed along the leader mast 30. It is said that As a method for running at an arbitrary speed, a pinion 25 that is interlocked by a drive motor 24 is attached to the support frame 20,
A structure in which the support frame 20 engages with a rack 31 formed in the vertical direction of the leader mast 30 and moves up and down by applying a reaction force to the leader mast 30 can be used. In this case, the current or voltage will be changed depending on the resistance of pushing into the ground 1, and construction management will be performed while continuously recording the value. Alternatively, instead of the rack 31 and pinion 25, a hydraulic mechanism may be used to move the support frame 20 up and down along the leader mast 30.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

1 to 3 show an example of a construction pile driving device, in which a support frame 20 supporting a drilling device 10 moves up and down along a leader mast 30.

This perforation device 10 has a casing 1 as an outer pipe.
1 and an inner tube 12 which also serves as a mortar injection tube, and the tip of the inner tube 12 is provided with a
An opening/closing shoe 14, a drilling bit 18, etc. as shown in Figure a are attached. In the figure, 13 is a stabilizer, and 17 is a head that pushes the excavated earth and sand to the side.

The drilling is performed by transmitting the rotation of a drive motor 21 fixed to a support frame 20 to the casing 11 via a ring gear (22 in the figure indicates a ring gear box).
This is done by rotating the casing 11 and the inner tube 12 fixed to the casing 11 as one body.
Note that the upper end of the inner tube 12 is supported via a hydraulic cylinder 27 provided on the support frame 20, and the inner tube 12 is supported by a hydraulic cylinder 27 provided on the support frame 20, and is attached to the casing 11 together with the save box 26.
It is possible to move a predetermined amount in the vertical direction. Also,
In the figure, reference numeral 16 denotes a connecting tube, in which a hardening material 2 such as mortar is fed into the inner tube 12 and injected into the ground 1 or the casing 11 from the tip of the inner tube 12.

When the hydraulic cylinder 12 is retracted as shown in FIG. 11b, the inner tube 12 is pushed downward relative to the support frame 20, and as shown in FIGS. The groove 43 and the locking portion 42 at the lower end of the casing 11 engage, and the inner tube 12 is fixed to the casing 11 and rotates as one when drilling. Further, the upper part of the inner tube 12 is a square tube 15 made of a square steel pipe or the like, and serves as a kelly bar.

The perforation device 10 is raised and lowered by means of spur teeth or racks 3 in the longitudinal direction of a leader mast 30 held vertically.
1, a pinion 25 that meshes with the pinion 25 is attached to the upper part of the support frame 20, and a drive motor 24 is installed.
This is done by Further, a roller 23 is attached to the support frame 20, and is adapted to run within a guide groove 32 formed in the leader mast 30 when moving up and down.

In addition, the tip of the inner tube 12 is generally of a type in which three shoes 14 are opened and closed around a hinge 41, but as shown in FIG. At this time, it is also possible to use a type that is left underground.

Figures 4a to 4i show an example of the construction process according to the construction method of the present invention, and the work is carried out in the following steps.

(a) Retract the hydraulic cylinder 27 and remove the casing 11.
and the inner pipe 12, set it on the stake and check the verticality.

(b) Rotate the casing 11 and apply pressing force,
The soil at the tip is forcibly moved to the side and deposited.

(c) When the casing 11 reaches a predetermined depth, the casing 11 is fixed, and the hardening material 2 such as mortar is pumped and injected from the tip of the inner tube 12 to a length (0.5 to 1.0 m) equal to the amount of hardening material injected. Pull up the inner tube 12. Note that the hardening material 2 such as mortar is mixed and kneaded in advance and then pumped.

(d) The hardening material 2 is pumped, the casing 11 and the inner tube 12 are stopped until the injection pressure reaches a predetermined pressure, and a knob-shaped enlarged portion 3' is created.

(e) While pumping the hardening material 2, the casing 11 and inner tube 12 are pulled up by a length equal to the injection amount.

(f), (g) Repeat steps (c) to (e) in the same way, and
We will continue to create.

(h) A pile 3 having a plurality of knob-like enlarged portions 3' is created.

(i) Before the hardening material 2 hardens, reinforcing bar cages 4 are inserted as necessary.

In addition, in the above work, the position and finished diameter of the enlarged part 3' depend on the type of soil and the casing 11.
It is controlled by the pulling length (0.2 to 1.0 m), the amount of hardening material 2 injected, and the injection pressure.

FIG. 6 conceptually shows a graph for construction management in the above embodiment.

When sinking the casing 11, the support frame 20 is lowered at a constant speed by the lifting drive motor 24, and the load is determined from the change in current or voltage of the drive motor 24 at this time, and the load is determined as shown in the graph of FIG. The shape shows the change in pressing force at each depth. Similarly, the rotational resistance is shown in the form of a graph from changes in current or voltage in the rotational drive motor 21. From these pressing forces and rotational resistance,
The ground strength and soil quality at each depth can be estimated, providing data for immediately determining the strength and performance of pile 3 during construction.

In addition, when pulling up the casing 11, the pulling speed was adjusted based on the relationship between the injection amount (/min) of the hardening material 12 and the injection pressure (Kgf/cm ² ), and a predetermined downward pressing force was applied to the casing 11. In this state, the hardening material 2 can be injected. This results in
While sufficiently distributing the hardening material 2,
This prevents non-uniformity in performance and quality, and provides a highly reliable pile 3. Furthermore, as shown in the graph, when the injection amount of the hardening material 2 is kept constant and the rise of the casing 11 is suppressed (the drive motor 24 is stopped), the injection pressure increases and an enlarged part 3' is formed in this part. be done.

8a to 8e show the relationship between the injection amount of hardening material 2 and the pulling length of inner tube 12 and casing 11. FIG.

That is, a indicates that the inner tube 12 is pulled up to a predetermined height by the hydraulic cylinder 27, and an amount of hardening material 2 equal to the lifted height is injected, and b indicates that the inner tube 12 and the casing 11 are further pulled up and When the amount of hardening material 2 equal to the upper length is injected, c and d have a pulling length of 80% and 50% of b, respectively, and when the same amount of hardening material 2 is injected, e does not pull up the casing 11. Add the same amount of hardening agent 2 to
This is the case when injected.

Figures 5a to 5h show the construction in another embodiment, and the work is carried out in the following steps.

(a) Retract the hydraulic cylinder 27 and remove the casing 11.
and the inner pipe 12, set it on the stake and check the verticality.

(b) Rotate the casing 11 and apply pressing force,
The soil at the tip is forcibly moved to the side and deposited.

(c) When the casing 11 reaches a predetermined depth, fix the casing 11 and inject the hardening material 2 such as mortar under pressure from the tip of the inner tube 12 to a length (0.5 to 1.0 m) equal to the amount of hardening material 2 injected. Only inner tube 12
pull up.

(d), (e) The hardening material 2 is continuously injected in a predetermined amount. Further, the pulling speed of the casing 11 is set to be a speed smaller than the injection volume, so that a downward pressing force is applied to the injected hardening material 2. In addition, construction management will be conducted using injection pressure.

(f), (g) After completing the injection of the hardening material 2, reinforcing bar cages 4, H-shaped steel, L-shaped steel, etc. are inserted as necessary.

(h) Creation of the pile 3 is completed by hardening of the hardening material 2.

FIG. 7 conceptually shows a graph for construction management in the above embodiment.

When the casing 11 is sunk, construction management is carried out in the same manner as in the previous embodiment.

The casing 11 is pulled up at a constant speed, and the enlarged portion 3' is not provided. Furthermore, the graph in FIG. 7 shows how the injection pressure decreases during the first injection when the tip of the inner tube 12 is pulled up into the casing 11 by the hydraulic cylinder 27.

FIGS. 12 and 13 show other embodiments,
This figure shows a pile driving device for leaving the casing 11 underground. In this embodiment, a ready-made auger machine 50 is attached to the support frame 2.
0', and when drilling, the expanding member 51 interposed between the inner tube 12 and the casing 11 is pressed against the inner surface of the casing, and the inner tube 12 and the casing 1 are
1 is rotated as one unit, and when pulling out, the expanding member 51 is pulled toward the inner pipe 12, the casing 11 is left in the ground 1, and the casing 1 is
The hardening material 2 is injected into the inside of the hardening material 1 (see Utility Model Application No. 185216/1983). In this case as well, the load on the drive motors 21' and 24 and the sinking speed of the device are measured during drilling, and the hardening material 2 is
Measures injection pressure, injection volume, equipment lifting speed, etc., and performs construction management.

〔Effect of the invention〕

This invention has the above-mentioned configuration, and the injection of hardening material such as mortar is performed while adjusting the rising speed of the casing and inner tube and receiving pressing force from above. etc., to prevent non-uniformity, and to reduce injection pressure,
By controlling the injection volume and pulling speed, highly reliable construction piles can be obtained.

In addition, the pile driving device uses the rotation of a pinion that engages with a rack provided on the leader mast to move up and down by applying a reaction force to the leader mast, and even when the injection pressure is large, the engaged part resists the injection pressure.
It can be forced to move up and down at any speed.
That is, it is possible to reliably pull out the device at a constant speed or to stop the device, and construction management is also facilitated.

In addition, it has the following advantages and characteristics.

The strength of the piles can be set arbitrarily, and the strength of the piles can be confirmed on the ground during the construction process.

Because the hardening material is mixed in advance, the strength of the hardening material is not affected by soil quality, as is the case with soil improvement methods.

It is possible to provide a hump-like enlargement at any depth.

It is economical because there is no overflow and the hardening material is used effectively.

[Brief explanation of drawings]

Fig. 1 is a front view of a pile driving device according to an embodiment of the present invention, Fig. 2 is a right side view thereof, Fig. 3 is a cross-sectional view taken from Fig. 2, and Figs. Cross-sectional view showing the construction procedure of piles, Figure 5 a~
h is a sectional view showing the construction procedure in another example,
Fig. 6 is a graph for construction management corresponding to Fig. 4 a to i, Fig. 7 is a graph for construction management corresponding to Fig. 5 a to h, and Fig. 8 a, b, c, d. ,e
9 is a cross-sectional view showing the relationship between hardening material injection amount and casing pulling length, and Figures 9a, b, c, d, and e are front views, bottom views, cross-sectional views of the tip of the pile driving device, and the stabilizer, respectively. Front view, also cross-sectional view,
Figures 10a and 10b are a front view and a vertical cross-sectional view showing an example of the tip of the inner tube, respectively. Figures 11a and 11b are front views showing a mechanism for lifting and lowering the inner tube, and Figure 12 is a cross-sectional view of another embodiment. The right side view of the pouring device, Fig. 13 is the 12th
FIG. 1...ground, 2...hardened material, 3...pile, 4...
... Rebar cage, 10 ... Perforation device, 11 ... Casing, 12 ... Inner pipe, 13 ... Stabilizer, 1
4...Tip opening/closing shoe, 15...Square tube,
16...Connection tube, 17...Head, 18...
... Bit, 20 ... Support frame, 21 ... Rotation drive motor, 22 ... Ring gear box, 23 ... Roller, 24 ... Lifting drive motor, 25 ... Pinion, 26 ... Swivel box, 27 ... ... Hydraulic cylinder, 30 ... Leader mast, 31 ... Rack, 32 ... Guide groove,
41... Hinge, 42... Locking portion, 43... Locking groove, 44... Connecting piece, 45... Point.

Claims (1)

[Claims] 1. While rotating the casing as an outer tube and an inner tube that also serves as an injection tube, the casing is sunk along a leader mast to a predetermined depth while being rotated as a unit, and when pulled out, a hardening material is poured from the tip of the inner tube. In the construction pile construction method, in which piles are created by press-fitting and hardening of the hardened material,
During drawing, the injection amount and injection pressure of the hardening material are continuously measured, and the rising speed of the inner tube or the inner tube and the casing is controlled according to the injection amount and injection pressure. A pile construction method characterized in that the hardening material is injected while adjusting the downward pressing force applied to the hardened material from the inner pipe or the inner pipe and the casing. 2. In a construction pile driving device in which a drilling device having a casing as an outer pipe and an inner pipe that also serves as a hardening material injection pipe is supported so as to be movable up and down along a leader mast, the inner pipe of the drilling device and the upper part of the casing A support frame is provided on the support frame, and a pinion that engages with a rack formed in the vertical direction of the leader mast and is driven by a drive motor is attached to the support frame, and the support frame takes a reaction force against the leader mast to achieve an arbitrary speed. 1. A construction pile driving device characterized in that it is configured to move up and down at the same time.