JPH0415849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for constructing foundation piles by burying ready-made piles such as precast concrete piles into the ground.

[Prior art and its problems]

If you use a pile driver that hits the pile head with a hammer, etc. to erect existing piles, severe noise and vibration will be generated during the pile driving process, which may have a very negative impact on the surrounding area of the pile driving site. .

Therefore, if a hole is first dug in the ground and the piles are built into the hole, the work can be done without noise or vibration, but a general excavator such as an earth auger is used to drill the hole. When this method is used, soil removal is extremely time-consuming, and problems remain with the pile's supporting capacity, such as the side walls of the drilled hole collapsing midway. In addition, multiple excavators must be used to create a cement bulb at the tip to increase bearing capacity, making the work process complicated and time consuming.

[Purpose of the invention]

The purpose of the present invention is to eliminate the disadvantages of the conventional example,
Pile holes can be constructed without discharging excavated soil at all, while reliably preventing collapse of the hole wall.Furthermore, bulbs for foot protection can be created at the same time without any effort, reducing the number of steps and streamlining construction. The present invention aims to provide a foundation pile construction method that achieves a highly reliable buried state of prefabricated piles.

[Key points of the invention]

However, according to the present invention, the purpose of the lever is to use an auger rod having at its tip a cutting blade capable of drilling with an expanded diameter and a tapered consolidation surface located above the auger rod. Start rotary drilling while injecting an appropriate amount of hardening material such as cement milk from the tip, excavate with a diameter larger than the diameter of the hole to be constructed, and pour the excavated soil mixed with hardening material such as cement milk onto the hole wall surface. The hole is compacted to stabilize the hole wall and increase the bearing capacity of the soil, and the hole is excavated to a specified depth. After the excavation is completed, cement milk for root hardening is injected to create a bulb at the end of the hole, and the excavation blade is reduced. This is achieved by injecting a predetermined amount of cement milk while raising the auger rod, and finally erecting the existing piles and curing the injected milk to complete the construction.

〔Example〕

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

First, to explain an example of the auger rod used in the construction method of the present invention, Fig. 1 is a side view of the rod 1, in which a digging blade 2 that can be expanded in diameter is provided at the tip, and the upper stage is tapered as it goes upward. A consolidated surface 3 was formed that expanded into a shape. The excavating blade 2 may have various structures, but it is one in which a plurality of excavating bits 2b are arranged and planted at the lower end of a blade body 2a that is supported pivotally by a pin and expands when surface pressure is applied from below. Details are shown in Figure 6.

In addition, various shapes of the consolidation surface 3 can be considered, and various examples thereof are shown in FIGS. There are two types: those in which the consolidation surface 3 rises in a straight line, as shown in FIGS. 4 and 5, and those in which the consolidation surface 3 rises spirally, as shown in FIGS. In any case, the uppermost end of this tapered consolidation surface is larger than the diameter of the rod 1, and the outside thereof is surrounded by a cylindrical hood 4 that opens downward, and the hood 4 is filled with consolidated excavated soil. A through hole 5 is provided as appropriate for the passage of the material.

Furthermore, as shown in FIG. 2, on the outer circumferential surface of the rod 1, a plurality of so-called trowel-shaped protrusions 6, which gradually protrude in the circumferential direction, are formed at appropriate intervals in the vertical direction. Further, an inflow pipe 7 is disposed to penetrate inside the rod 1, and its tip opens as a spout 8 near the excavation blade 2.

Although not shown, the upper end of the rod 1 is connected to, for example, a drive device installed in a three-point support pile driver, and the upper end of the inflow pipe 7 is connected to a drive device for injecting hardening material such as cement milk through a swivel mechanism. Connected to the hose.

Next, the construction method of the present invention using the above device will be explained. FIG. 7 is a longitudinal explanatory view showing each step of the present invention. First, as shown in a, a pile driver is set on the pile core, the propulsion rate of the rod 1 is checked, and the rod 1 is cut into the ground while being rotated. At this time, the cutting blade 2 expands in diameter due to the surface pressure, and a cutting diameter larger than the diameter of the rod 1 is obtained. At the same time, if an appropriate amount of cement milk is poured into the ground as a hardening agent through the inlet pipe 7 and the spout 8, the excavated soil and the cement milk are kneaded and a soil concrete-like material is obtained. 3, and is discharged from the through hole 5 toward the outer peripheral surface of the rod 1. and protrusion 6
It is applied to the borehole wall by the action of a trowel. In this way, as the auger rod 1 excavates, the hole wall is consolidated with the mixture of cement milk and the excavated surface, and a sinking layer 9 is formed.

In this way, when the excavation is completed to a predetermined depth as shown in c, cement for root hardening is poured out from the spout 8 to form a bulb 10 at the lowest end of the excavated hole. Then, while retracting the digging blade 2 and pouring a predetermined amount of hardening milk from the spout 8, the auger rod 1
(see d, e). ] After the pile hole is created in this way, a pre-formed hole 11 such as a concrete pile is built before the cement milk hardens. When the cement milk around the existing pile 11 such as the concrete pile hardens, the pile construction is completed and the tip of the pile 11 is supported by the bulb 10.

〔Effect of the invention〕

As described above, the foundation pile construction method of the present invention is
When erecting prefabricated piles into the ground, excavate with a diameter larger than the diameter of the hole to be constructed while injecting a hardening material such as cement milk, and apply the excavated soil mixed with the hardening material such as cement milk to the hole wall surface. This compaction method aims to stabilize the hole wall and increase the bearing capacity of the soil, eliminating the need to remove excavated soil to the ground, and also making it possible to create bulbs for foot protection all at once using the same device.
Moreover, since a painted wall-like layer is formed on the hole wall, there is no risk of collapse, and there is no need for a stabilizing liquid such as bentonite solution, making it possible to streamline construction with fewer steps.

Furthermore, the surroundings of the built-in existing piles are solid, so that highly reliable piles can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of the auger rod used in the construction method of the present invention, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, and Figs. 3 to 5 are diagrams showing each embodiment of the consolidation surface portion. 1 is a view taken along line B-B in FIG. 1, FIG. 6 is a front view of the diameter-expandable excavation blade portion, and FIG. 7 is a vertical cross-sectional view showing each step of the construction method of the present invention. DESCRIPTION OF SYMBOLS 1...Auger rod, 2...Diameter expandable drilling blade, 2a...Blade body, 2b...Drilling bit, 3...
...Consolidation surface, 3a... Protrusion, 4... Hood, 5...
Through hole, 6... Trowel-shaped protrusion, 7... Inflow pipe, 8...
...pour spout, 9...painting layer, 10...bulb, 1
1... Ready-made pile.

Claims (1)

[Claims] 1 Using an auger rod that has a cutting blade that can expand its diameter and a tapered consolidation surface located above it, harden an appropriate amount of cement milk, etc. from the tip of the rod with the cutting blade expanded. Start rotary excavation while injecting material, excavate with a diameter larger than the diameter of the hole to be constructed, and compact the excavated soil mixed with hardening material such as cement milk on the hole wall surface to stabilize the hole wall and ground the hole. Dig to a predetermined depth while trying to increase the bearing strength, and after the excavation is complete, cement milk for root hardening is injected to create a bulb at the end of the hole, and then the predetermined amount of cement milk is injected with the excavation blade retracted. while pulling up the auger rod,
A method of constructing foundation piles characterized by finally erecting pre-fabricated piles and curing the injected milk to complete the construction.