JPH0140173B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a construction method for embedding and fixing piles used for building foundations in underground excavated holes, and in particular, to a construction method that eliminates the need for existing piles. This invention relates to a method of embedding piles using a vibration method and ensuring reliable integration with the ground.

(Conventional technology) Traditionally, when constructing buildings on soft ground, concrete piles, cast-in-place piles, etc. have been constructed to stabilize the ground and to increase the supporting load. It is common practice to construct a building after constructing a concrete foundation and pouring a cloth foundation on top of it.

In addition, in the case of houses and small-scale buildings, since the weight of the building is small, instead of driving existing concrete piles directly into the ground, earth drills, augers, etc. are used. A pile hole is excavated and a ground improvement agent is mixed into the soil inside the hole.
The mixture is often hardened to increase the load-bearing capacity of the ground.

The above-mentioned ground strengthening method, which is generally called the ground stabilization method, is compared to the conventional method of driving prefabricated piles directly into the ground.
Although the load-bearing strength of piles is low, this method is often used in construction in residential areas because it can reduce the effects of noise and vibration.

The construction method described above uses a drilling member such as an earth drill as described in Japanese Patent Application Laid-open No. 56-153012, etc., to drill a hole of a predetermined size in the ground, and A soil improvement agent is ejected from a nozzle formed at the tip of the soil and mixed with the soil. Cement milk or other chemicals are used as the soil improvement agent. .

However, in the conventional ground improvement method, although the amount of soil in the pile hole increases due to excavation, the soil improver is mixed into all of the soil, which hardens after construction. Currently, we are having difficulty disposing of Shimatsuta soil.

In addition, when forming a foundation using ready-made piles such as concrete knotted friction piles with a triangular cross section, excavate with something like an earth drill and pour cement milk etc. into the hole. Although the piles are then driven in with a hammer, the pile holes drilled with an earth drill have the same cross-section, whereas the conventionally used friction piles As we get to the part,
It is formed so that it becomes gradually thinner.

Therefore, although this construction method creates a relatively large space around the pile with a triangular cross section, the cement milk poured into the hole is liquid and highly fluid. for,
It is not possible to reliably consolidate the inside of the pile hole, and sometimes the soil around the pile collapses or loosens, which causes the ground around the pile to cave in. , structures with unstable foundations such as adjacent concrete block walls and wooden buildings may be affected by the ground sinking, and it is difficult to take countermeasures. be.

(Problems to be Solved by the Invention) The present invention solves the drawbacks of conventional construction methods as described above. By calculating the amount of soil and removing the excess soil before mixing the soil improvement agent, it is easier to dispose of the remaining soil, and it is also possible to drive ready-made piles into the muddy soil that has been mixed with the soil improvement agent. The purpose is to consolidate the muddy soil in the pile and to integrate the area around the pile hole with the pile body.

(Means and effects for solving the problems) The present invention provides an excavating device that includes an excavating portion and a nozzle at the tip of the rod, and forms a portion formed only by the rod of a predetermined length on the upper portion thereof. A screw is placed on the top of the rod and these are connected together.

When excavating pile holes, the amount of increase in soil due to excavation, the amount of increase in soil due to mixing with soil improvement agent,
The volume of the prefabricated piles that will be driven later and the depth of the concrete foundation are calculated in advance, and the amount of soil to be removed calculated based on these is then removed from the ground using a screw when excavating the pile hole. After the soil is discharged, the soil remaining in the hole is mixed with a ground improvement agent.

After that, prefabricated piles such as those made of concrete are driven in, and the prefabricated piles are surrounded by compacted muddy soil formed by mixing and stirring a soil conditioner, and as the soil hardens. , the existing pile and the ground are bonded together to improve the strength of the pile and to prevent loosening of the ground around the pile.

That is, in the excavation equipment of the present invention, as described above, the amount of soil to be removed from the excavation hole is calculated in advance, and the position of the screw provided at the top of the equipment is adjusted in accordance with the amount of soil to be removed. can be set. When excavating a pile hole with a drilling device, unnecessary soil can be removed in one operation of excavation, so it is possible to excavate the pile hole, remove the soil, and mix the soil improvement agent. This allows the operations to be performed continuously.

(Example) The structure of the pile and excavation device of the present invention will be explained according to the illustrated example. As shown in FIG.
The excavation device of the present invention is provided so as to be movable up and down along a post 5 supported by a truck 1 via arms 2 and 2a.

The truck 1 is provided with a winch 3, by means of which a wire 4 is wound up, passing through an upper member 6 equipped with a pulley so that the head member 10 is suspended. The slider 12 of the head member 10 is guided by a guide rod 11 provided along the post 5, and is guided by a drive device 13 such as a hydraulic motor for driving the screw 16 and the excavation part 18. has been established.

The excavating device of the present invention is composed of a screw 16 connected to the drive device 13 as described above, a rod 17 connected to the lower part of the screw 16, and an excavating section 18. As in the case of commonly used devices, there are excavating teeth provided at the bottom and a large number of protruding stirring blades 18a of a predetermined shape above the excavating teeth. In the above-mentioned drilling equipment of the present invention, the screw 1
The length of 6 can be set in accordance with the length of the pile hole to be excavated and the amount of soil to be removed from the pile hole. In other words, the lengths of the excavation part 18 and the rod 17 provided at the bottom of the device are set according to the amount of soil that needs to be left in the pile hole.
By the screw 16 provided on the upper part,
Actions that can remove unnecessary soil are now performed.

The rod, screw, and excavation part used in the above-mentioned drilling equipment of the present invention each have a hole formed in the center of their shaft, and the slurry etc. supplied from the slurry inlet 14 at the top thereof are It is ejected from a nozzle 19 formed under the excavated portion 18 through holes formed in each member.

Therefore, cement milk or the like used as a soil improvement agent is mixed with water and other chemicals in a mixer 7, and then supplied to an injection port 14 via a hose 9 by a pump 8, and then passed through a hollow screw or rod. , is ejected from the nozzle 19, and the stirring blade 1
8a performs mixing and stirring with the soil.

In the device of the present invention, the screw 16 is formed with spiral wings 16b protruding around a hollow shaft 16a, as shown in FIG. 2, and the connecting portion between the screw 16 and the rod 17 is As shown in FIG. 3, a protrusion 17a provided at the tip of the rod 17 is inserted into a hole below the screw 16 and fixed with a screw 16c.

Further, the rod 17 and the excavated portion 18 can be connected by the above-mentioned fixing method,
Furthermore, it is of course possible to connect these shaft members using other methods.

Further, a rest stop 15 is formed on the post 5 and is connected to the head member 10 via a rope or the like and configured to move the post 5 up and down over a predetermined range, and prevents the rod 17 etc. from swinging. However, this stopper 15 is designed to prevent the screw 1 from
6, it will be opened so as not to get in the way.

Next, the operation when excavating a pile hole using the apparatus of the present invention will be explained based on FIG. 4.

First, as shown in FIG. 4A, the post 5 is positioned at the location where the pile foundation work is to be performed, the drive device 13 is activated, and excavation of the pile hole 23 is started. As shown in Figure B, the soil 21 excavated by the excavator 18 is stirred and loosened in the pile hole 23 while the excavator 18 and the rod 17 are submerged under the ground 20. It is located at the top and is slightly raised.

Next, as shown in C, when the screw 16 enters the hole 23, the soil loosened in the pile hole 23 is discharged onto the ground by the screw. When the hole 23 is excavated to a predetermined depth, the amount of soil 22 determined in advance by calculation is discharged to the ground by the rotation of the screw 16.

The amount of soil discharged is the amount of muddy soil 24 formed by mixing and stirring a ground improvement agent into the soil 21 excavated in the pile hole 23, as shown in Figure D. , in order to leave only a predetermined amount.

For example, the amount of soil left in the pile hole 23 is determined by the factors of the size of the hole excavated by the excavator and the expansion coefficient of the soil loosened by the excavation of the hole. minus the amount of soil needed. In addition, in this calculation, it is of course necessary to take into account that the volume of soil will increase by mixing the soil improvement agent as the amount of soil left in the pile hole.

In the construction method of the present invention, when the pile hole 23 of a predetermined depth is excavated and the calculated amount of soil has been removed in the state shown in C, the excavated part 18 is pulled up while rotating. At the same time, the soil conditioner is spouted from the nozzle 18a, and the soil 21
Mix soil conditioner.

When performing this mixing and stirring work, 1
When mixing only once is insufficient,
The excavation part 18 is immersed into the muddy soil 24 again,
It is possible to repeat the operation of continuing to supply the soil improvement agent and mixing a predetermined amount of the soil improvement agent into the soil 21, but these operations are similar to the construction of conventional cast-in-place piles. will be carried out.

In the construction method using the excavation equipment of the present invention, the amount of muddy soil mixed with the ground improvement agent and left in the pile hole 23 is at the level of the ground 20, as shown in D. The depth will be L lower than the depth.

After that, a prefabricated pile 26 made of concrete or the like is driven into the pile hole 23, and the length of the prefabricated pile is the same as the depth of the pile hole 23. This is determined according to the depth H of the pile hole, and the ready-made pile 26 is slightly driven in and its tip is fixed to the bottom of the pile hole.

The prefabricated pile 26 used in the present invention includes knot 2
It is made of concrete and has piles 7 protruding at predetermined intervals, and is fixed at a predetermined depth position by driving the piles 26 into muddy soil with a hammer or the like. That's what I do.

When driving a prefabricated pile into this pile hole 23, the muddy soil 24 with poor fluidity inside the hole 23 is consolidated and wraps around the pile 26 without any gaps, and the ground is improved in that state. The agent will harden.

Therefore, in the construction method of the present invention, it is possible to prevent the soil around the pile hole 23 from collapsing or loosening after the prefabricated pile is driven and until the muddy soil hardens. Definitely prevented.

Furthermore, in the construction method of the present invention, drilling of pile holes, mixing of soil improvement agent, and driving of existing piles are performed in a very short period of time, and only the soil required for forming piles is used. is left in the pile hole 23, and the excess soil is removed before being mixed with the soil improvement agent, so that the removed soil will not be contaminated with excess materials such as the soil improvement agent. Because you haven't
It becomes easier to dispose of the soil.

In addition, the ground improvement agent used in the construction method of the present invention is mainly a mixture of cement, water, foaming agent, etc., but it is also possible to mix a hardening accelerator, etc., or change the amount of cement, water-cement, etc. Naturally, the ratio should be determined according to the properties of the soil and the design strength of the pile.

In addition, in the construction method of the present invention, as described above, the top of the pile is formed in a state that is aligned with the bottom surface of the cloth foundation, so after driving the pile, the ground is dug and the pile is It is possible to immediately place concrete for a cloth foundation with the head exposed.
Unlike conventional construction methods, there is no need to cut the pile heads to a predetermined depth from the ground and then pour concrete for the foundation.

(Effects of the Invention) Since the construction method of the present invention is as described above, it is possible to drive prefabricated piles very easily without generating vibrations, noise, etc. The formed pile is formed because the space between the surrounding area of the pile and the wall of the pile hole is filled with hardened soil in a consolidated state, and the pile body and the ground are formed integrally. It is possible to ensure sufficient strength.

In addition, since the soil that has been removed from the pile holes in advance has not been mixed with soil conditioners, it can be used again in other locations, and unlike conventional construction methods, it is possible to use hardened soil. No situation arises that makes disposal difficult.

Furthermore, in the construction method of the present invention, the soil improvement agent is mixed only with the soil necessary for forming the piles, thereby reducing the amount of soil improvement agent used. It becomes possible to reduce the cost of pouring.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the equipment used in the construction method of the present invention, Figs. 2 and 3 are explanatory diagrams showing the configuration of the screw and the connection part between the screw and the rod, respectively. - E are explanatory diagrams showing the steps of the pile driving method of the present invention, respectively. Symbols in the diagram 1...Dolly, 2...Support arm, 3...
Winch, 4...Wire, 5...Post, 6...Upper member, 7...Mixer, 8...Pump, 9...Hose, 1
0... Head member, 11... Guide rod, 12... Slider, 13... Drive device, 14... Inlet, 15... Stop, 16... Screw, 17... Rod, 18
... excavation part, 19 ... nozzle, 20 ... ground, 21 ... excavated soil, 22 ... discharged soil, 23 ... pile hole,
24...Muddy soil, 25...Hardened soil, 26...Prefabricated pile, 27...Node.

Claims (1)

[Scope of Claims] 1. A digging part for excavating is provided at a certain length at the tip of a hollow rod, and a nozzle for spraying a ground improvement agent is provided at the tip of the rod, An excavating device is provided in which a part consisting only of a rod of a predetermined length is formed in the upper part of the excavation part of the rod, a screw member is provided on the upper part, and each of the above-mentioned members is integrally formed in the vertical direction of one rod. At the same time, when the excavation equipment excavates a pile hole in the ground, a screw formed above the excavation part,
Excess soil that is not needed for pile formation is removed, and then a ground improvement agent is injected from a nozzle to mix it with the soil, compacting the muddy soil, and inserting the existing pile into it. A pile embedding method characterized by embedding the piles.