JPH0610367B2 - Pile burying method - Google Patents

Description

The present invention relates to a so-called low-pollution pile embedding method with low vibration and low noise, and embedding a relatively small-diameter pile that is incapable of the conventional hollow excavation method and twist-in method. Regarding construction method.

Conventionally, various burial construction methods with low pollution have been invented and implemented. They are roughly classified into a so-called middle excavation method in which a spiral auger is inserted into the hollow part of the pile to simultaneously excavate and bury the pile, and a so-called pre-auger method in which a hole is excavated in the ground in advance and a hard hole is dropped therein.

Among the medium excavation methods, the method of constructing root-fixing bulbs at the tip of the pile by high-pressure injection of expanded wings or cement milk is an excellent method that can obtain relatively high bearing capacity without hitting, but spiral auger is used. Due to the nature of the construction method in which it is inserted into the hollow part of the pile and excavated and set down, it is limited to a relatively large diameter pile.

In order to obtain the same supporting force in the pre-auger construction method as well, in order to develop the supporting force, the pile is twisted and press-fitted. However, even in this case, it cannot be applied to a small-diameter pile having a small resistance torsion moment.

INDUSTRIAL APPLICABILITY The present invention is a method of burying a pile in which a supporting force can be obtained for a relatively small-diameter pile that cannot be screwed in, and a drilling fluid for preventing collapse of the hole wall is discharged from the tip of the auger screw. While drilling to a predetermined depth, pulling out the auger screw, then press-fitting a prefabricated pile with both ends open to the bottom of the excavation, and after inserting the injection pipe, insert the injection tube through the hollow part of the pile to form a root-curing bulb. The injection tube for injection breaks the lid and injects cement milk at a high pressure from the tip of the injection tube for root-curve formation while projecting from the lower end of the stake, and laterally jetting it to the desired depth at the tip of the stake. It is a pile construction method to create solid bulbs.

The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the steps up to the embedding of the pile in the rightward sequence from to. Drilling while releasing the drilling fluid from the tip of the auger screw 1 to prevent collapse of the hole wall,
After reaching the predetermined ground, the auger screw is pulled out while appropriately rotating in the normal direction or in the reverse direction while injecting the rake peripheral surface frictional force expressing liquid 6 (the direction is indicated by an arrow).

As the rake peripheral surface frictional force expressing liquid 6, a liquid containing slaked lime, granulated blast furnace slab, gypsum, Portland cement or the like is preferably used.

Next, the pile 2 having a relatively small diameter, which cannot be formed by the medium excavation method or the twist-in method, is press-fitted to the excavation bottom surface by its own weight or by placing a weight on the head. At this time, since the tip of the pile 2 is closed by the lid 3, it is possible to completely prevent the injection liquid or the like from flowing into the hollow portion 7 of the pile.

The lid 3 has a shape as shown in FIG. 2, and the material of the lid 3 is such that it has a strength capable of withstanding the water head difference at the time of sinking the pile, and is a material that will later be broken by the injection tube for root fixation. ,
Any material may be used as long as it does not hinder the subsequent excavation and drilling by the injection tube for root fixation, but polymer materials, ALC, Noro, etc. are considered appropriate in terms of price. This lid 3 is manufactured in advance in the required shape and size, and it is used by attaching it to the tip that is difficult to embed before piling, or by attaching this lid 3 to the formwork or rebar cage at the time of stake manufacturing You may make it into and use it.

After the rake peripheral surface frictional force expressing liquid 6 is hardened, as shown in FIG. 3, the injection tube 4 for forming root-fixing bulb is pierced through the lid 3 and projected downward from the rake tip through the hollow 7 in the rake, and the tip of the rake is cut. Cement milk is injected into the unexcavated ground portion 8 at a medium pressure or a high pressure in a direction perpendicular to the axis of the injection pipe to form a root-curing bulb 5.

According to the present invention, the following effects can be obtained.

Since the scoop with the lid provided at the tip is inserted, the injection liquid such as the drilling liquid and the earth and sand present in the drilling hole do not enter the hollow part of the scoop. Therefore, even if the piling has a relatively small diameter, the outer diameter of the filling pipe is sufficiently smaller than the inner diameter of the piling, so that the filling pipe can be easily inserted up to the tip of the piling after inserting the piling.

It is necessary to fix the injection tube to the lid at the bottom of the plow to create a root-bulb with a predetermined depth at high pressure while breaking the lid and projecting the injection tube for root-conduit formation from the lower end of the plow. Instead, the work of attaching and detaching the injection pipe, which is required when fixed to the lid, is not required, and the construction becomes efficient.

Therefore, it can be applied to the burying method with a relatively small diameter pile.

Furthermore, according to the method of the present application, since the injection pipe can be projected from the lower end of the pile, it is possible to form a root-fixing bulb having a sufficient diameter (a diameter larger than the diameter of the pile) and a depth in the lower part of the pile. Since the hardening liquid can be injected during excavation, the excavated soil and the cement milk are sufficiently mixed, and therefore, even for a relatively small-diameter pile, a pile having a desired tip supporting force can be obtained.

Example The pile test method of the present invention was carried out using a pile having an outer diameter of 350 mm, and a loading test was conducted after the root cement bulb injected with cement milk at high pressure was completely cured. The results are shown in Table 1.

For comparison, an attempt was made to embed a pile with an outer diameter of 350 mm and a tip without a lid. Of course, the root-curing bulb was formed by injecting cement milk at high pressure as in the example. Since the screw auger used in the conventional hollow excavation method does not fit into the hollow part of this small-diameter pile, a small-diameter screw auger was used.

In addition, at the time of implementation, in order to measure only the supporting force at the tip of the pile, the bentonite solution was filled on the peripheral surface of the pile,
Consideration was made to reduce the frictional force on the rake face.

As a result, in the comparative example, it was quite difficult to lower the injection pipe to a desired depth, and the high supporting force as in the present invention could not be measured.

Reference example Comparison of bearing capacity of piles constructed by the medium excavation method and those wishing to be constructed using the equipment used in the construction method of the present invention using a pile with an outer diameter of 400 mm to which the conventional medium excavation method can be applied. did. Further, as in the above-mentioned Examples, it was considered that the pile peripheral surface was filled with the bentonite solution to reduce the frictional force on the peripheral surface of the pile so that only the supporting force at the tip of the pile could be measured.

The results are shown in Table 2. In Table 2, a stake constructed using the apparatus used in the construction method of the present invention is indicated as Reference Example 1, and a stake constructed by the medium excavation method is indicated as Reference Example 2.

As can be seen from Table 2, the bearing capacity of Reference Example 1 and Reference Example 2 are equal, and the pile embedding method of the present invention is a conventional hollow excavation method or a relatively small-diameter pile that cannot be twisted. When it is done, it exerts an excellent effect.

The absolute value of the bearing capacity shown in Table 1 is lower than that of the bearing capacity shown in Table 2 because the diameter of the consolidation bulb was changed based on the difference in the outer diameter of the pile.

[Brief description of drawings]

FIG. 1 is a schematic side view showing the step of embedding the pile according to the present invention. Second
The figure is a sectional view and a plan view of the side of the rake tip used in the present invention. FIG. 3 is a schematic side view of a rooting process according to the present invention. 1 ... Auger screw, 2 ... Pile, 3 ... Lid, 4 ... Injection tube for forming root gland bulb, 5 ... Root root bulb, 6 ... Liquid for expressing friction force on pile face 7 ... Hollow part of pile , 8 …… Soil tip ground

Claims (1)

[Claims] 1. A method of burying a relatively small diameter pile that is not possible with a medium excavation method or a twist-in method, and is drilled to a predetermined depth while releasing a drilling fluid from the tip of an auger screw to prevent hole wall collapse. Make a hole, pull out the auger screw, and then press fit the ready-made pile with both ends open with lids to the bottom of the excavation.After pressing, insert the injection tube for root-curing bulb formation through the hollow part of the pile, Excavation and cement milk injection are performed by laterally high-pressure jetting cement milk from the tip of the injection pipe while projecting the tip from the bottom of the plow, and a sill embedding method for forming a root solid bulb at the tip of the plow.