JPS60119816A - Formation of continuous pile - Google Patents

Abstract

PURPOSE:To form a continuous pile with good efficiency by a method in which the ground is excavated to the rock-bed layer by an auger, an air hammer drill is inserted into the pipe for protecting the pit wall, the rock-bed layer is excavated, and concrete is placed. CONSTITUTION:An auger 14 is turned by an auger rotator 16, and a casing pipe 12 is turned reversely by a casing pipe rotator 20 for excavation. When the pipe 12 reaches a rock-bed layer 24, the auger 14 is pulled out, a pipe 28 for protecting the pit wall is inserted into the pipe 12, and the pipe 12 is pulled out. An air hammer drill 30 is inserted into the pipe 28 and a bit 32 is turned by a rotator 34. Compressed air is then supplied from a compressor 37, and the rock-bed layer 24 is excavated by using impact forces by means of the air hammer mechanism. The drill 30 is pulled out of the pipe 28, and then concrete is placed into the pipe 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for constructing continuous piles, and particularly to a method for constructing continuous piles suitable for constructing continuous piles in rock layers.

[Prior art]

Continuous piles used for impermeable walls, continuous walls, earthen basins, etc. are constructed by excavating single holes that partially overlap. Conventionally, this single hole excavation that includes a collapsed layer has been carried out using a simultaneous casing method using an earth auger, etc. However, although excavation using an earth auger is relatively efficient for digging soft layers such as earth and sand, , there was a problem that made it impossible to excavate hard rock.

[Purpose of the invention]

The present invention has been made in view of these circumstances, and an object of the present invention is to propose a continuous pile construction method that can efficiently create continuous piles even on hard rock using a large-diameter air hammer drill.

[Structure of the invention]

In order to achieve the above object, the present invention uses a casing pipe that protects the hole wall and a drilling device that can pass through the inside of the casing pipe, and makes the casing pipe follow the excavation hole of the drilling device to prevent the hole wall. The collapsed layer is excavated until reaching the bedrock layer using the simultaneous casing construction method, which excavates while protecting the casing, and the excavation equipment is recovered with the casing pipe remaining underground, and then an air hammer drill is inserted into the casing pipe. Insert hard rockff1lTF
Drill Q, then create a pile using cement and a solidifying agent in the excavated hole, and then partially overlap the excavated holes and repeat the steps from the simultaneous casing method to the pile creation to create a continuous pile. It is characterized by

〔Example〕

A preferred embodiment of the continuous pile construction method according to the present invention will be described in detail in accordance with the attached drawings F+J.

(11) Excavation of Collapsed Layer Figures 1 to 3 show casing pipe and auger excavation, which is a type of simultaneous geosinking method, and Figure 1 shows the auger pile core set. 10 is a base machine, 12 is a thick-walled gauging pipe for drilling with a bit at the lower end, 14 is an auger with a screw-shaped rotating blade, and 1 stone is an auger rotation device provided on the post 18 of the base machine 10. , 20 is a casing pipe rotation device also provided on the post 18, and 21 is a guide' for the casing pipe 12.The auger 14 is rotated around the center of the pile as shown in FIG. The auger rotation device 16 rotates the auger, and the casing pipe rotation device 20 rotates the casing pipe 12 in the opposite direction to excavate as shown in FIG. 2, and the excavated debris is sent to the ground by the screw action of the auger. In addition, in Fig. 2, the reference numeral 22 indicates a soft collapsed layer consisting of earth and sand, etc.
4 is a hard rock layer. As shown in FIG. 3, when the excavation of the collapsed layer 22 is completed and the casing pipe 12 reaches the bedrock layer 24, it becomes impossible to excavate, so only the auger 14 is pulled out with the casing pipe 12 erected. In this case, the hole wall of the drilled hole 26 is connected to the casing pipe 12.
It is protected by , so there is no chance of it collapsing. Further, excavated soil 27 remains inside the casing pipe 12.

Next, as shown in FIG. 4, the hole wall protection pipe 28 is inserted into the thick-walled casing pipe 12 using the vibrator 30, and then, as shown in FIG. 5, the hole wall protection pipe 28 is left in place. and pull out the thick inner casing pipe 12. The reason why the thick inner casing pipe 12 is replaced with the thin-walled hole wall protection pipe 28 is that the casing pipe used for excavation requires a large torque and proof strength, so a dedicated thick-walled casing pipe 12 with high rigidity is required. However, the rigid casing pipe for preventing the back of the hole wall 1 after excavation does not require a rigid casing pipe, and the +rli 111i thick casing pipe 12 can be used effectively at other excavated locations.

(2) Drilling of the rock layer Figure 6 shows the air hammer drill 3 inside the hole wall protection pipe 2B.
An air hammer drill 30 is installed on the boss 18 of the base machine 10 along with a rotating device 34 and a drilling pipe 35. A rotational force is applied to the bit 32 of the air hammer drill 30 by a rotating device 34, compressed air is sent from a compressor 37, and an impact force is applied by an air hammer mechanism (not shown), so that the rock layer 24 can be excavated with high efficiency. . The focus 32 is removably installed on an anvil 36 that receives direct impact from the air hammer mechanism, and is used to remove damaged bits 32.
This has a large economical effect because only the screw can be replaced, and this makes it easier to excavate large diameter rock. Of course, the bit 32 can also be a single bit that is integrally constructed with the anvil of the torpedo. Further, if the bit 32 is configured to be expandable and contractible, a simultaneous casing method can be used when excavating the rock mass 24. Figure 7 shows air hammer drill 30
The excavated debris is ejected to the ground by the exhaust air of the air hammer drill.

(3) Concrete pouring Figure 8 shows the air hammer drill 30 being inserted into the hole wall protection pipe 2.
Figure 9 shows the state of pouring concrete and the construction of continuous piles after pulling out from Figure 8.
It is a top view along the IX line. In FIG. 8, 38 is a mixer, 40 is a bonopa, 42 is a pump, and 43 is an injection pipe. Cement and a solidifying agent such as concrete are poured into the hole wall protection pipe 28 from the pump 42, and then the hole wall protection pipe 28 is removed. The above-mentioned excavation and concrete placement may be carried out every other place as shown in Fig. 10 (shaded areas in the figure are concrete), or once the concrete has solidified, continuous excavation may be carried out as shown in Fig. 11. Good too. Furthermore, as shown in FIG. 12, continuous excavation can be performed by providing an H-shaped guide 44 or the like within the already excavated tag. FIGS. 13 to 15 show other embodiments of the present invention. As shown in FIG. 14, when large-diameter rocks 45 are scattered in the collapsed layer 22, the excavation efficiency of auger excavation decreases. For this purpose, under reaming drilling using an air hammer drill 46 (patent application 1987-187) was carried out.
268). That is, as shown in FIG. 14, the bit 48 is expanded to a larger diameter than the outer diameter of the casing pipe 12 to perform under-reaming excavation, thereby simultaneously erecting the casing pipe 12 and excavating the collapsed layer 22. After finishing, the bit 48 is reduced in diameter, the casing pipe 12 is removed, the air hammer drill 46 is inserted, and the rock is excavated.

In FIG. 13, 46a is a rotating device for the air hammer drill 46, and 47 is a rotating device for the casing pipe. still,
Since the casing pipe 12 is constructed by under-reaming excavation, the casing pipe is excavated by a power jack 49 installed at the mouth of the excavation hole as shown in Fig. 14, without using the casing pipe rotating device 47 as shown in Fig. 13. It is also possible to push in at the same time. The subsequent operations are the same as those shown in FIGS. 4 to 8, so their explanation will be omitted. Further, according to the under-reaming method of the air hammer drill described above, it is also possible to excavate a single rock to a target depth without replacing the air hammer drill bit.

As shown in FIG. 11, after concrete is poured, sheet piles 50 are erected to create a water-shielding wall of continuous piles.

In addition, in the case of earth retaining piles, casing pipe (or H rigid)
After erecting the building, concrete is poured and piles are created while the building is erected.

〔Effect of the invention〕

As explained above, according to the continuous pile construction method of the present invention, the collapse layer is excavated by the simultaneous casing method to prevent collapse of the borehole wall, and the collapse layer is
Since Wt is excavated using an air hammer drill, it is possible to perform continuous pile excavation in the IX type.

[Brief explanation of drawings]

Figures 1 to 3 are drawings showing the state of excavation of the collapsed layer by casing pipe auger excavation, WSt is a front view of the casing pipe auger excavator, Fig. 2 is a cross-sectional view showing the state of excavation by the auger, and Fig. The figure is a cross-sectional view showing the state in which the casing pipe remains after auger excavation, Figures 4 and 5 are cross-sectional views showing the replacement of the casing pipe, and Figures 6 and 7 are Fig. 8 is an explanatory diagram showing the state of concrete placement; Fig. 9 is a sectional view taken along the line ■-■ in Fig. 8; Figs. 10 and 11 show the excavation and concrete placement. Figure 12 is an explanatory diagram showing the order of pouring.
Figures 15 to 15 are drawings showing other embodiments of the present invention, in which Figure 13 is a front view of an air hammer drill excavator, and Figure 14 is a front view of an air hammer drill excavator.
This figure and FIG. 15 are cross-sectional views showing the state of excavation of a collapsed layer containing rocks. 12...Casing pipe, 14...Auger, 22
... Collapse layer, 24... Rock layer, 28... Hole wall protection pipe, 30... Air hammer trill, 38...
・Mixer, 42...Pump, 43...Injection pipe. Figure 4 Figure 5 Top C Figure 6 Figure 7 Figure 14 Factor 15

Claims (1)

[Claims] Using a casing pipe and a drilling device that can pass through the inside of the casing pipe, the casing pipe follows the excavation hole of the drilling device and excavates while protecting the hole wall, until reaching the bedrock layer. The collapsed layer is excavated, the drilling equipment is recovered with the casing pipe left underground, and then an air hammer drill is inserted into the casing pipe to excavate the hard rock layer, and then cement and A rock mass characterized in that a continuous pile is created by creating piles using hardening and other agents, and repeating the operations from the above-mentioned simultaneous method to the above-mentioned pile creation by partially overlapping the excavated holes. 1. Continuous pile construction method for one kidney.