JPS6140814B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing piles in the ground, in which the ground 3 is excavated while spouting an earth and sand solidifying agent 2 such as cement milk from the lower end of an excavation shaft 1, and the excavated earth and sand are separated from each other. The first mixed pile 4 is prepared by mixing with the solidifying agent 2.
A first step in which the lower end of the excavation shaft 1 is reached at a predetermined position by digging while forming the soil in the soil, and a first step in which the primary mixed soil 5 lifted to the ground by the excavation of the excavation shaft 1 is sieved. The oversized gravel 6 is removed, and then a soil consolidation agent such as cement or fly ash is added to the primary mixed soil 5 from which the oversized gravel 6 has been removed, and the mixture is re-kneaded to obtain the required strength. In the second step of producing the secondary mixed soil 7 and in the creation of the first mixed pile 4, after the lower end of the excavation shaft 1 reaches a predetermined position, the earth and sand consolidation agent 2 in the first step is transferred from the lower end of the excavation shaft 1 to the soil consolidation agent 2 in the first step. On the contrary, the excavation shaft 1 is pulled up while pressing out the secondary mixed soil 7 produced in the second step and filling it into the excavation hole 8, and the pile 9 filled with the secondary mixed soil 7 is pushed out into the excavation hole 8. The present invention relates to a method for constructing piles in the ground, characterized by comprising a third step of forming piles.

As a conventional method of constructing piles in the ground, for example, the method disclosed in Japanese Patent Publication No. 50543/1983 is known. In this conventional example, cement milk was simply squirted out while excavating the ground, and the cement milk was mixed at the same time as the excavation to form the pile. For this reason, no matter how much the mixture is mixed underground, it is impossible to form a pile with uniform strength in the vertical direction. In addition, in this conventional example, since the cement milk is mixed with the excavated soil in the borehole, if the concentration of cement milk is high, the fluidity is low, which causes problems in mixing with the excavated soil in the borehole. As a result, the amount of cement used was small and the strength of the piles formed was weak. Furthermore, another conventional example involves discharging all excavated soil to the ground and filling the excavated hole with mortar, etc., but in this case, the soil lifted to the ground must be disposed of, and filling is required separately. The disadvantage was that sand had to be prepared for use, which increased costs.

The present invention was invented in view of the above-mentioned conventional drawbacks, and its purpose is to be able to construct piles that are uniform in the vertical direction and have the required design strength, and to facilitate the disposal of soil that has been lifted above the ground. It is less necessary, can be reused, reduces costs, and also prevents the inside of the excavation shaft from clogging or being unable to extrude the secondary mixed soil when extruding it from the tip of the excavation shaft. To provide a method for constructing piles in the ground that can be smoothly pushed out without any problems.

The present invention will be explained in detail below with reference to Examples. In the figure, reference numeral 1 denotes a hollow pipe-shaped excavation shaft, on the outer periphery of which a screw part 10 for soil lifting and stirring, or a stirring blade 11, or both the screw part 10 and the stirring blade 11 are provided. The excavation shaft 1 has a hollow pipe shape and has a bit 12 at the lower end.
A spout 1 is provided at the lower end of the excavation shaft 1.
3 is provided. In this case, the spout 13 may be provided in the bit 12 portion as in the embodiment shown. The excavation shaft 1 may be one or a plurality of shafts arranged side by side. In the case of a plurality of excavation shafts 1, the plurality of excavation shafts 1 may be arranged laterally in a straight line, in an arcuate manner, or in a polygonal shape such as a triangle or a quadrangle. When a plurality of excavation shafts 1 are arranged, the upper end of each excavation shaft 1 is connected to a multi-axis device 14, and the rotation of the drive device 15 is transmitted to each excavation shaft 1 via the multi-axis device 14. 1 in the diagram
6 is a hose connected to the excavation shaft 1 in communication. However, when the hose 16 is connected to the earth and sand consolidation supply device 20 for supplying the earth and sand consolidation agent 2 such as cement milk, the earth and sand consolidation agent 2 such as cement milk is spouted from the lower end of the excavation shaft 1 and the ground is 3, excavated earth and sand are mixed with earth and sand consolidation agent 2 to form a primary mixed pile 4 in the soil, and the lower end of the excavation shaft 1 is brought to a predetermined position. The above step is referred to as the first step. On the other hand, the primary mixed soil 5 lifted to the ground by the excavation shaft 1 is passed through a sieve 17 to remove oversized gravel 6, and then the oversized gravel 6 is removed and the primary mixed soil 5 is removed. A soil solidifying agent such as cement or fly ash is added to the soil so as to obtain the required design strength, and this is remixed by the mixer 18 to produce the second mixed soil 7. This is the second step. Here, 19 in the figure is a secondary mixed soil manufacturing and supplying device, which sucks the paste-like primary mixed soil 5. The secondary mixed soil production and supply device 19 includes a suction section 22, a sieve 17, a mixer 18, a pump (not shown), and the like. Next, in creating the first mixed pile 4, the second mixed soil 7 produced in the second step is extruded from the lower end of the excavation shaft 1 into the excavation hole 8 instead of the earth and sand consolidation agent 2 in the first step. While filling, the excavation shaft 1 is pulled up and the secondary mixed soil 7 is filled into the excavated hole 8 from the bottom upwards, thereby creating a pile 9 filled with the second mixed soil 7 in the excavated hole 8. Form. This is the third step. In the third step, the hose 16 is connected to the second mixed soil production and supply device 19. In addition, when the secondary mixed soil 7 is squeezed out into the excavation hole 8 during the third step, the primary mixed soil 5 constituting the primary mixed pile 4 is lifted up to the ground one after another. 1st mixed soil 5 to 2nd
A second mixed soil 7 is prepared by the next mixed soil preparation and supply device 19, and is again pressure-filled into the excavation hole 8 from the lower end of the excavation shaft 1. At this time, the excavation shaft 1 may be pulled up while rotating, or may be pulled up without rotating. Further, by pressure filling the excavation hole 8 with the secondary mixed soil 7 from below, the excavation shaft 1 and the primary mixed soil 5 are pushed upward. Piles 9 having the required design strength are formed in the ground through the first, second, and third steps described above. If necessary, a fourth step may be added after the third step in which steel pipes or other structural members 21 are erected to provide the bending strength and other strength required for the pile 9. Although a single pile 9 may be constructed as described above, a retaining wall can be formed by forming the piles 9 in succession so that their ends overlap each other. In FIG. 3, when each excavation shaft 1 rotates, the multi-axis device 14 also rotates, so that the plurality of excavation shafts 1 rotate as a whole.

In the present invention, as described above, the ground is excavated while spouting an earth and sand solidifying agent such as cement milk from the lower end of the excavation shaft, and the excavated earth and sand are mixed with the earth and sand solidifying agent to perform the first mixing. The first step is to excavate while forming piles in the soil and reach the lower end of the excavation shaft at a predetermined position.The first step is to add cement, fly ash, etc. to the first mixed soil lifted to the ground by the excavation shaft. The second step is to add soil consolidation agent to the required strength and re-knead it to produce the second mixed soil, and the lower end of the excavation shaft reaches the specified position during the creation of the first mixed pile. After that, from the lower end of the excavation shaft, the second mixed soil produced in the second process is squeezed out from the bottom end of the excavation shaft, filling it into the excavation hole, and the excavation shaft is pulled up. The third step consists of forming piles filled with secondary mixed soil.
Ultimately, the entire length of the excavation hole in the vertical direction is filled with secondary mixed soil that has been adjusted to a predetermined strength, and the piles are constructed, making it possible to easily form piles with a predetermined strength. There are advantages and second
The mixed soil does not need to be stirred in the excavation hole, so even if it contains a large amount of cement and is highly concentrated, there are no problems, and high-strength piles can be formed. Furthermore, in the second step, the primary mixed soil lifted to the ground by the excavation axis is sieved to remove oversized gravel, so that there is no oversized gravel in the secondary mixed soil. Therefore, the hose, the inside of the excavation shaft, and the spout of the excavation shaft will not get clogged, and as a result, even if the primary mixed soil lifted to the ground is reused, it will not clog from the spout of the excavation shaft. There is no problem in ejecting the mixed soil, and the secondary mixed soil can be reliably filled into the excavated hole. In addition, since the mixed soil removed above the ground is reused when forming the piles, there is less need to dispose of the removed earth and sand, and sand, etc., which will be used as the material for the secondary mixed soil, can be prepared separately. Since it is not necessary, the cost can be significantly reduced. In addition, since the first mixed pile is formed by mixing excavated soil and soil consolidation agent,
During excavation and during filling with the second mixed soil, the first mixed pile made of the first mixed soil prevents collapse of the hole, and when filling the second mixed soil, the second mixed soil and the first mixed soil Even if some of the primary mixed soil remains without being completely replaced with the secondary mixed soil, the primary mixed soil is a mixture of excavated soil and soil consolidation agent, so it will eventually be formed. The pile is mainly made of secondary mixed soil, and is entirely made of a mixture of excavated earth and sand and an earth and sand consolidation agent.

[Brief explanation of the drawing]

Figure 1 a, b, c, d is a schematic diagram showing the construction sequence of the present invention, Figure 2 a, b, c is a schematic diagram showing an example of an excavator used in the above, formation of the first mixed pile Cross-sectional view at the time and cross-sectional view at the time of pile formation, Figure 3a,
b is a schematic diagram showing another example of the same excavator as above and a cross-sectional view at the time of forming the first mixed pile, in which 1 is the excavation shaft, 2 is the earth and sand consolidation agent, 3 is the ground, and 4 is the first 5 is the first mixed soil, 7 is the second mixed soil, 8 is the excavated hole, and 9 is the pile.

Claims (1)

[Claims] 1. Excavating the ground while spouting an earth and sand consolidation agent such as cement milk from the lower end of the excavation shaft, and excavating while mixing the excavated earth and sand and the earth and sand consolidation agent to form a first mixed pile in the soil, The first step is to reach the lower end of the excavation shaft at a predetermined position, and the first mixed soil lifted to the ground by the excavation of the excavation shaft is sieved to remove gravel with large grains, and then the gravel with large grains is removed. A second step of adding a soil consolidation agent such as cement or fly ash to the first mixed soil to obtain the required strength and kneading it again to produce a second mixed soil;
After the lower end of the excavation shaft reaches a predetermined position in the creation of the first mixed pile, the second mixed pile, which is manufactured in the second step in place of the earth and sand consolidation agent in the first step, is applied from the lower end of the excavation shaft to the predetermined position.
The third step is to press out the mixed soil and fill it into the excavation hole while pulling up the excavation shaft to form a pile in which the excavation hole is filled with the second mixed soil. Construction method.