JPH0325121A - Sinking of pile in inner drilling pile method - Google Patents

Abstract

PURPOSE:To make sure and effective sinking of a pile feasible at inner drilling pile method by adopting a combined method consisting of expanded digging at a required depth, normal inner drilling pile method at an intermediate depth and construction of an expanded bulb part at the final depth. CONSTITUTION:A ready-made pile 1 having an expanded part 1' at its end is sunk as the ground at the forefront is dug with an auger 4 penetrated into the hollow part of the pile. At execution of such inner drilling pile method, expanded digging is made at a required depth with an expandable digging device 3 installed at the end of the auger 4 and, at the same time, the pile is sunk with periphery-consolidating liquid 5 injected into spaces made by the digging and agitated therein. At an intermediate depth, the expandable digging device 3 is folded and digging and sinking are progressed by means of normal inner drilling pile method in a diameter the same is that of the pile. At a final depth, the expanded digging is made further with foundation-consolidating liquid 6 gradually injected therein, and an expanded bulb part 7 is constructed thereby.

Description

Detailed Description of the Invention "Field of Industrial Application" This invention relates to a pile sinking method in the medium excavation method, particularly a method in which a pile having an enlarged diameter part with a large diameter at the tip or lower part is sunk by enlarging excavation (m). "Prior Art, Problems to be Solved by Invention" Conventionally, piles with a large enlarged diameter section at the tip or bottom have been constructed using the hammering method, the hollow digging method, or the pre-poling method. Generally, 4.5 is used because voids are created around the pile during construction.
As shown in the figure, sand or gravel is poured from the ground during or after the pile is sunk, or the surrounding area is filled with fixative or powder using an injection pipe inserted into the void, resulting in voids or disturbed soft areas. A pile sinking method is being implemented to restore or strengthen the area. However, the above conventional construction method has the following problems. ■If the filling work is to be carried out after the piles have been sunk, the process will be twice as much work, and the construction period will be longer.

■If filling is carried out at the same time as pile sinking, additional workers and machinery will be required, which will be uneconomical.

■The filling effect is uncertain because the voids may collapse or there may be unfilled areas.

■The degree of recovery or reinforcement of the ground cannot be adjusted freely depending on the depth.

■In the case of piles where the pile surface is negative compatible (applying an anti-itching agent to the pile surface to reduce frictional force), filling will damage the g-friction agent on the surface and reduce its S-reducing effect. .

"F Stage for Solving Problems" In order to solve the above-mentioned conventional problems, the present invention provides a ready-made pile l having an enlarged diameter part 1' at the tip, and an enlarged excavation device 13 at the tip inserted into the hollow part. In the medium excavation method, in which the pile is deposited while excavating with the auger 4 equipped, the expansion excavation device II13 is used to expand the excavation at the required depth, and the pile 1 is sunk without stirring the surrounding fixative injected into the excavation gap, and the intermediate layer is At the depth, the enlarged excavation device 'jl3 is scaled down and excavated to about the diameter of the pile using the normal medium excavation method, and at the final depth, the enlarged bulb part 5 is constructed by further enlarging the excavation while injecting root solidification liquid. This paper proposes a pile sinking method.

"Operation of the Invention" For example, while enlarging excavation to the upper depth with the enlarging excavation device 3, the pile l is sunk without stirring the surrounding fixing liquid consisting of cement milk, sand, and other fillers injected into the excavated gap. By doing this, it is possible to perform the work of sinking the pile and filling the void at the same time, and by expanding the excavation, it is possible to perform the work of filling the void in the M chain.
There are no unfilled areas, ensuring a reliable filling effect, and the horizontal strength of this area is ensured. After that, at the intermediate depth, the enlarged excavation equipment 3 is scaled down and excavated and deposited to about the diameter of the pile using the normal medium excavation method, so that the surrounding area is kept loose and the effect of negative frictional force due to ground subsidence etc. is reduced. suppressed.

Furthermore, in the subsequent lower depth, by enlarging and sinking the surrounding area while injecting and agitating the surrounding demarcation liquid with the enlarging excavation equipment 'j13, it is possible to perform the work of laying the pile and filling the void at the same time. Since the surrounding fixative liquid is agitated and filled into the excavated cavity without any blockage, a reliable filling effect is obtained with no unfilled areas, and a reliable support force is obtained due to the positive frictional force of this area. ``Example'' Below, an example that clearly shows this invention will be explained.
The prefabricated pile 1 to be sunk according to the present invention has an enlarged diameter part l° at the tip, and the outer periphery of the middle part is coated with an anti-friction agent 2, and when the pile is sunk, an enlarged excavation device 3 is installed at the tip inside the hollow part. An auger 4 is inserted into the pile, and the pile is sunk using the medium excavation method while excavating the ground at the tip of the pile.

Then, as shown in Fig. 1(a), if the N value is somewhat high (see Fig. 2), the enlarging excavation device 3 is extended to perform enlarging excavation, and at the same time, the peripheral fixing liquid 5 is injected. While stirring the mixture, the ready-made piles 1 are placed.

Next, at intermediate depths where the N value is low, as shown in Figure 1(b), the expansion drilling device 3 is scaled down and, if necessary, water or air is injected before excavation and sinking is carried out to a depth similar to the diameter of the pile. .

Furthermore, at a depth of 1"W where positive friction can be expected, Figure 1 (C
), the surrounding fixing liquid 5 is again injected and stirred using the enlarging excavation device 3, and the excavation is enlarged and deposited.

Finally, at the final depth where the N planting is high (support J'I! board), as shown in IF/1 (c), the expanding excavation device is greatly expanded while injecting the root solidifying liquid 6, and the same as before. Construct the enlarged bulb part. The ready-made pile l may have a flat tip as shown in Fig. 3(a), or may have a sharp tip as shown in Fig. 3(b), and the surrounding area] ．． It is desirable to make it easier for rIl constant solution or root hardening solution to wrap around the outside of the pile. Furthermore, the anti-friction agent 2 on the outer periphery of the middle part of the ready-made pile 1 does not necessarily have to be coated. ``Effect of Explosion 1j'' As shown in 1 below, according to this IJJ, a. While expanding the excavation using the expansion excavation device at the desired depth, the void around the pile is sufficiently formed, and the area around the pile J'! ! It is possible to reliably improve the board by injecting and filling the surrounding area with fixing fluid at the same time as excavation.

In addition, at intermediate depths, the expansion drilling rig is scaled down.
If the pile surface is coated with a history-reducing agent when it is excavated and deposited to a diameter of the pile using the normal medium-drilling method without using surrounding fixative, it can be deposited without damaging the pile, and the surrounding area is loosened. In this situation, the effect of negative yI friction force due to ground subsidence, etc. can be steadily suppressed.

[Brief explanation of drawings]

Figure 1(a). (b). (c). (d) is pile sinking,
T' of dead construction. /f! Fig. 2 is a vertical cross-sectional view showing an example of the construction J1 corresponding to the construction process in Fig. 1! ! Figure 3 is a partial vertical cross-sectional view showing the tip shape of the ready-made pile used in this invention, and Figures 4 and 5 are vertical cross-sectional views showing conventional pile sinking construction. ．． 1. Ready-made pile,
1' - Expanded diameter part, 2 - Anti-friction agent, 3 - Expanding excavation device, 4 - Auger, 5 - Peripheral fixing liquid, 6 - Root solidifying liquid.

Claims (1)

[Claims] 1) In the medium excavation method, in which a prefabricated pile with an enlarged diameter portion at the tip is dug and sunk by an auger equipped with an enlarging excavator at the tip inserted into the hollow part, the fixing liquid is poured around the area at the required depth by the enlarging excavator. The pile is deposited by enlarging excavation while pouring and stirring, and at the intermediate depth, the enlarging excavation equipment is reduced to excavate and deposit to the same extent as the pile diameter, and at the final depth, the enlarged bulb part is constructed while injecting root solidifying liquid. A pile sinking method in the medium excavation method characterized by the following.