JPS5985024A - Method and apparatus for formation of foundation pile in soft ground - Google Patents

Abstract

PURPOSE:To attain the improvement of the ground and the enhancement of bearing force of a pile by a method in which while excavating the ground by an expanded excavation blade provided at the lower end of a hollow shaft, cement milk is injected to form large-diameter lumps in the lower end part of the soil cement pillar. CONSTITUTION:A hollow shaft 1 is normally turned, and while excavating the ground excavation blades 5 and 9 being penetrated, cement milk is injected from a jet nozzle 3 and mixed with excavated soil by a stirring blade 2 to form a pit 10 of much the same diameter as that of a fixed blade lever 4. After the pit 10 reaches a given depth, the shaft 1 is reversely turned to pull it up to a given height, whereupon an expandible excavation blade 5 is opened outwards against the resistance of the ground, a rotary lever 6 is coupled with a coupler piece 8, an enlarged diameter condition is produced to form an expanded hole 11, and large-diameter lumps 12 are formed. When the shaft 1 is pulled up while being turned normally, the excavation blade 5 becomes a shrunk condition and goes up in the pit 10, and the pillar part 13 of a foundation pile is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a construction method for constructing foundation piles in soft ground, etc., and an apparatus for the construction.

In recent years, the housing situation around major cities has been worsening due to soaring land prices and high commodity prices, and houses are now being built on soft ground, which was previously avoided. With foundation structures similar to cloth foundations, the ground tends to settle unevenly over time, often causing problems such as tilting and deformation of houses.

Therefore, currently, the foundations for houses built on soft ground are driven by wooden piles, small-diameter concrete piles, or small-diameter steel pipes, and then a cloth foundation or solid foundation is placed on top of the foundations. This causes vibration, which is a problem in densely populated residential areas, and if the supporting ground is deep, long and large diameter piles are required, resulting in a large amount of foundation costs.

The present invention is particularly suitable as a base for a densely populated residential area on soft ground as described above, and improves the surrounding ground by creating fill cement pillars by injecting and stirring cement milk into the soft ground around the piles. , by creating a large-diameter nodule at the lower end and/or middle part, the conventional drawbacks are improved,
The aim is to improve the ground, increase pile bearing capacity, and reduce construction costs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the construction method and apparatus of the present invention will be described below with reference to the drawings.

First, the device used in the method of the present invention will be explained with reference to FIGS.
... project horizontally, and a grout spout 3 is provided at the lower end of the hollow shaft 1 in the horizontal direction. Furthermore, a pair of upper and lower fixed tributary rods 4゜4, which are formed longer in the horizontal direction, are attached to the lower end of the hollow shaft 1, and a rotary rod having digging blades 5, 5 at the tips thereof is attached between both ends thereof. The other end portions 6, 6 are rotatably attached by vertical shafts 7, 7.

At both ends of the fixed tribute rods 4, 4, there are rotary rods 6, 6.
A locking piece 8.8 is provided to prevent rotation in one direction from the maximum opened position, that is, the position protruding parallel to the fixed tributary 4 as shown in FIGS. 1 and 2. At the same time, the lower surface of the arm rod 4 located further below has cutting edges 9, 9 for digging.
is installed protrudingly.

Due to the above-mentioned configuration, the excavating blade 5, which is attached to the rotating rod 6 and can be opened and closed, can be moved from the enlarged diameter state where the rotating rod 6 is locked to the locking piece 8 as shown in FIGS. 1 and 2. , FIGS. 3 and 4, the rotating rod 6 can be freely opened and closed until it is rotated inward to a reduced diameter state.

The construction method of the present invention is carried out using the apparatus described above. First, cement milk is supplied from the upper part of the hollow shaft 1, and while injecting it from the spout 3, the hollow shaft 1 is rotated clockwise in the forward direction a (Figs. 4 and 5) to press it into the ground, and then press it into the ground. The excavation progresses while mixing and stirring the excavated soil and cement milk by repeating the motion. Excavation at this time is mainly performed by the excavating cutting edge 9, and the opening/closing excavating blade 5.5 receives resistance from the ground, etc., and becomes a closed diameter-reduced state as shown in FIGS. 3 to 5.

Therefore, a hole 10 having a diameter corresponding to the rotation locus of the fixed tribute rod 4 is formed in the ground, and at the same time, the excavated soil of the hole is well mixed with cement milk.

When the hole 10 reaches a predetermined depth by such excavation, the hollow shaft 1 is rotated counterclockwise b (Figs. 2 and 6) to the required height as shown in Fig. 6. Perform the pull-up.

Then, the opening/closing excavation blade 5 is opened outward due to the resistance of the ground, and the rotary rod 6 is locked to the locking piece 8, expanding the diameter and widening the excavation. At the lower end of 10, an enlarged hole 11 with a height corresponding to the lifting amount of the device is formed, and at the same time, the enlarged hole 11 is filled with a mixture of excavated soil and cement milk, and a large-diameter nodule 12 is created. It will be done.

After that, the hollow shaft 1 is rotated in the forward direction a again, and if necessary, cement milk is injected and the device is moved up and down while being pulled up, and the opening/closing drilling blade 5 returns to its original diameter-reduced state and the hole adjustment 10 is adjusted. The hard hole 10 is filled with cement milk mixed with the excavated soil by the agitation action of the digging blade 5.9 and the fixed blade rod 4, and the columnar shape of the foundation pile is formed as shown in Fig. 7. Section 13 will be created.

Furthermore, in the construction method of the present invention, the large-diameter nodules 12 can be created not only at the lower ends of the columnar sections 13 as described above, but also at the middle portions of the columnar sections 13. In such a case, during the lifting process of the device, the hollow shirt 1 can be reversely rotated to raise it to the required height while injecting cement milk. A baby boom section 14 will be created. FIG. 8 shows the large-diameter nodules 14, 14 created at two intermediate locations of the columnar section 13 by this operation.

As explained above, the present invention provides a button at the lower end of a hollow shaft provided with a large number of stirring blades, a foundation pile provided with an opening/closing excavation blade whose protruding length changes depending on the direction of rotation of the shaft, and a grout spout. Using a construction device, while injecting cement milk, the open/close drilling blade rotates the hollow shaft in the closing direction to excavate to the required depth, and then the open/close drilling blade rotates in the opposite direction in the opening direction to form an enlarged excavation hole. At the same time, cement milk is mixed with the excavated soil to create a large diameter nodule, and then the hollow shaft is rotated in the normal direction to close the opening and closing excavation sides and pulled up while mixing the excavated soil and cement milk. Even during the process, the hollow shaft is rotated in the opposite direction to create a large-diameter nodules as necessary, making it possible to improve soft ground and significantly increase the supporting capacity of foundation piles in the same ground. Therefore, it is possible to shorten the depth of foundation piles or reduce the number of foundation piles, thereby significantly reducing construction costs, especially when supporting small-scale buildings such as ordinary houses on soft ground. Suitable for creating foundation structures. Further, the construction device according to the present invention has many advantages, such as being extremely simple in structure, inexpensive to manufacture, and extremely easy to operate.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the device of the present invention, Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1, and Fig. 3 shows the device in a closed state with the opening/closing stirring blades. Side view, Figure 4 is Figure 3B-
5 is a side sectional view showing the excavation state of a columnar foundation pile hole; FIG. 6 is a side sectional view showing the state of excavating a large diameter hole at the lower end of the columnar foundation pile hole; FIGS. 7 and 8 are side sectional views showing the construction of large-diameter nodule sections at the lower ends and intermediate portions of columnar sections using the construction method of the present invention. 1... Hollow shaft 2... Stirring blade 3... Grout inlet 4... Arm rod 5... Drilling blade 6°゛・Rotating rod 9... Drilling blade 10... Hole adjustment 11・
...Enlarged hole 12...Large diameter baby boom part 13...Columnar part 14...Intermediate large diameter baby boom part Patent applicant Yoshi
1) Cultivation

Claims (3)

[Claims] (1) An opening/closing digging blade whose protrusion length changes depending on the direction of rotation of the shaft is installed at the lower end of the hollow shaft equipped with stirring blades, and a foundation pile construction device equipped with a grout spout is connected to the cement from the spout. While injecting milk, the opening/closing drilling blade is rotated forward in the closing direction to excavate to the required depth, and then the hollow shaft is rotated in the opposite direction to open the opening/closing drilling blade to form an enlarged hole while at the same time drilling into the large diameter nodule section. A method for constructing foundation piles in soft ground, etc., which is characterized by creating a columnar section on a large-diameter nodule section by pulling up a hollow shaft while rotating the opening/closing excavation blade in a positive direction in the closing direction. (2) The method according to claim 1, characterized in that, in the pulling process, the hollow shaft is rotated in the opposite direction to create an intermediate large-diameter nodule portion at a required location in the middle of the columnar portion. (3) At the lower end of the hollow shaft with a large number of protruding stirring blades, a cutting edge for digging and a grout spout hole are provided, as well as a fixed blade rod, and the blade rod is provided with Dota resistance due to the rotational pressure of the hollow shaft. A foundation pile construction device for use in soft ground, etc., characterized by having an opening/closing excavator blade that automatically rotates and automatically changes its protrusion length.