JPH0749754B2 - Vertical hole excavation method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vertical hole excavation method, and is particularly adopted in a method of excavating and forming a vertical hole in the ground such as a cast-in-place pile method and a continuous underground wall method. Vertical hole excavation method.

<Prior art> For example, during excavation work for forming a vertical hole in the ground in a continuous underground wall construction method, in order to prevent the wall surface of the vertical hole from collapsing, while pouring and filling a liquid stabilizing material into the vertical hole. As well as excavating, the stabilizing material mixed earth and sand generated by the excavation are discharged from the vertical holes.

As this liquid stabilizing material, it has been most common to use an aqueous bentonite solution in the past, while performing excavation while maintaining the inside of the drilling vertical hole at a predetermined viscosity, and an aqueous bentonite solution overflowing from the upper end opening of the vertical hole. A mixture of excavated soil is collected.

<Problems to be solved by the invention> However, when the collected bentonite mixed earth and sand is discarded, it is treated as industrial waste, and when it is dumped as it is, the place becomes muddy, so disposal The current situation is that I am having a hard time.

In consideration of the above problems, the present invention is capable of easily treating the collected mixed earth and sand, and the ground for excavating vertical holes has a fine particle content of 15% or less or a small amount of fine particle content. Even in the case of water gravel ground or sand gravel ground with fine particles of several% to 15%, it is possible to prevent the collapse of the wall surface of the vertical hole and to easily discharge the stabilizing material mixed sand from the vertical hole due to overflow. The purpose of the present invention is to provide a vertical hole excavation method.

<< Means for Solving the Problem >> In order to achieve the above object, the vertical hole excavation method of the present invention is
In the method of excavating and forming vertical holes in the ground such as cast-in-place pile method and continuous underground wall method, excavation is carried out while protecting the collapse of the wall surface of the vertical hole by the liquid stabilizing material injected and filled into it.
And a vertical hole excavation method in which the stabilizing material mixed earth and sand generated by excavation is overflowed from the upper end opening of the vertical hole and discharged, wherein the liquid stabilizing material is a bubble-containing solution, or a super absorbent water-containing resin solution. Alternatively, one of the mixtures of the two is used, and the additive having a defoaming or degelling action is sprayed on the stabilizing agent-mixed earth and sand discharged to the ground.

<< Action >> According to the present invention, by performing excavation while injecting a bubble-containing solution or a superabsorbent resin or a mixture of both as a stabilizer, a predetermined viscosity of the stabilizer-mixed earth and sand inside the vertical hole, Fluidity and water stoppage are imparted to the ground where vertical holes are to be excavated. The ground has a fine particle content of 15% or less, the agglomerate ground with a small amount of fine particle content, or a few% to 15% of fine particle content. % Even if it is a gravel ground, etc., the wall surface of the vertical hole is stably held and the discharge of the stabilizing material mixed sand due to the overflow is facilitated.

Also, by spraying an additive material with a defoaming or degelling action in the state where the stabilizer mixed sand is collected, the bubbles and / or gel-like substances in the mixed sand disappear, so that the subsequent excavation sand treatment is not possible. It will be easier.

<< Embodiment >> An embodiment of the present invention will be described in detail below with reference to the drawings.

The figure shows an example where the vertical hole excavation method of the present invention is applied when the vertical hole E1 is excavated and formed in the ground during the construction of the connecting wall by the cast-in-place pile method or the continuous underground wall method. FIG.

In this construction method, the guide pipe 1 installed on the ground surface is used as a guide, and the rod 2 for excavation is used to excavate the vertical hole E1 in the excavated ground E.

The stabilizing material to be injected into the above-mentioned excavated soil is the rod for excavation 2
Eject from the drill bit 3 at its tip through the center of the
Mix with the excavated earth and sand in the excavation well E1.

In addition, the stabilizer mixed earth and sand generated during such excavation work,
Through the notch 1a formed on one side of the guide pipe 1, it overflows into the collection tank 4 installed on that side and is stored therein.

Next, the mixed sediment is fluid-transferred to the closed sediment hopper 6 through the pipe 5, and is sequentially transferred from the hopper 6 to the dump truck 7 located therebelow.

The defoaming material and / or the degelling material are sprayed by the sprayer 20 to the mixed earth and sand stored in the recovery tank 4 to eliminate them.

Further, by connecting the earth and sand hopper 6 to the vacuum pump 8 and sucking the air, the disappearance of the air bubble component remaining in the mixed earth and sand can be promoted.

As the ground to which the above-mentioned excavation method is applied, the following soil soils are particularly effective.

Ground with a fine grain content of 15% or less.

Aerated gravel ground with a small amount of fine particles.

Sand gravel ground with fine particles of several% to 15%.

Next, specific examples will be described.

(A) When using a bubble-containing solution alone as a stabilizing material: A foaming agent is dissolved in water, foamed 6 to 25 times by stirring or the like, and injected into the excavation vertical hole E1 from the tip of the excavation bit 3.

As the foaming agent, there are a surfactant and a protein-based foaming agent, and a thickener may be appropriately added to strengthen the bubbles. Due to the foaming, the apparent viscosity in the drilling vertical hole E1 becomes 2000 to 10000 cps, and while the drilling earth and sand are mixed and dispersed in the bubbles, the apparent viscosity and the presence of the high specific gravity mixture keep the wall of the vertical hole stable.

When the foaming ratio is set to the above-mentioned foaming ratio, it is preferable to add about 1 to 3 times to 100 parts of water.

As a concrete device for producing bubbles, as shown in the drawing, a stirring and mixing tank 9 for mixing water and a foaming agent, a pump 10,
There is a hose 11, an air compression pump 12, and a foaming device 13 connected in the middle of the hose 11.By blowing the high-pressure air created by the compression pump 12 into the foaming device 13, the foaming agent solution foams and its state (Bubbling solution) is injected from the tip of the hose 15 through the rod 2 for drilling from the tip of the drill bit 3.

In addition, the air-bearing sediment that overflowed to the ground side was collected in the recovery tank 4
Then, the air bubbles disappear by spraying a defoaming material, and it becomes soil containing water. Since water can be supplied when air bubbles disappear, separation of soil and water becomes easy.

As the defoamer, higher fatty acid ester, mineral oil, higher alcohol, etc. are used. Considering economic efficiency and defoaming property, the amount of spray is 20-80c for 1000l of collected mixed sand.
c is enough.

If a thickener is added, it will be 1/50 to 1/20 of the amount used.
It is advisable to add the enzyme preparation of No. 0 to the defoamer and then spray it.

(B) When using a superabsorbent resin solution simple substance as a stabilizer: The superabsorbent resin is mixed with water to increase the viscosity, and this is supplied into the excavation vertical hole E1 from the tip of the excavation bit 3.

As the super absorbent resin, there is sodium polyacrylate,
The wall surface of the vertical hole can be kept stable by adding 0.4 to 0.7 parts to 100 parts of water according to the soil quality of the excavated ground and adjusting the viscosity to 1000 to 10000 cps.

As a device for producing the highly water-absorbent resin solution, a device excluding the compression pump 12 and the foaming device 13 from the illustrated device can be used.

The mixed earth and sand that have overflowed to the ground side is transferred to the inside of the recovery tank 4, and the sprayer 20 further sprays the gelling agent, so that the viscosity is reduced and becomes sand containing water.

Salts such as CaCl ₂ and Ca (OH) ₂ are used as the gel breaker. The amount of spray is 4 against 1000 = of mixed sand collected.
It is about 7 kg.

(C) When using a mixture of air bubbles and a super absorbent resin solution as a stabilizer: The above super absorbent resin is added to water to adjust the viscosity to 1000 to 1000.
After adjusting to 0 cps, a small amount of a foaming agent is mixed, foamed 1.5 to 4 times by stirring or the like, and supplied from the tip of the drill bit 3 into the drill vertical hole E1.

Due to the thickening effect of the super absorbent resin and the foaming of the foaming agent, the apparent viscosity in the drilling vertical hole E1 becomes 1500 to 60,000 cps, and the wall surface of the vertical hole is kept stable while mixing and dispersing the drilling earth and sand in the foam.

In addition, in this embodiment, since the thickened solution is foamed, the film of bubbles is strengthened, the time until disappearance becomes long, and the wall surface of the vertical hole can be further stabilized.

Further, the air bubbles and the super absorbent polymer mixed earth and sand which have overflowed to the ground side are transferred to the recovery tank 4, where the additives are sprayed to be gelled and the air bubbles disappear.

With the disappearance of air bubbles, water contained in the earth and sand can be supplied, so that separation from the earth and sand becomes easy.

As the defoaming and degelling agent, CaCl ₂ , Ca (O
H) 2 and other salts are used.

The amount of spraying, considering economic efficiency, desolving gel and defoaming property,
About 4 to 7 kg is sufficient for 1000 l of collected mixed sand.

<< Effects of the Invention >> As described in detail with reference to the above embodiments, in the present invention, a vertical hole is formed by excavating while introducing a bubble-containing solution or a superabsorbent resin as a stabilizing material. It imparts a predetermined viscosity, fluidity, and water-stopping property to the internal stabilizer mixed sand to facilitate the discharge of the stabilizer mixed sand due to overflow while maintaining the wall surface of the vertical hole stable, and to mix the stabilizer. It is possible to easily remove air bubbles and / or gel-like substances in the mixed sediment by spraying an additive with a defoaming or degelling action in the state where the sediment has been collected. be able to.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a vertical hole excavation method according to the present invention. E ... excavation ground, E1 ... excavation vertical hole 2 ... excavation rod, 3 ... excavation bit

Claims (1)

[Claims] 1. In a method of excavating a vertical hole in the ground, such as a cast-in-place pile method or a continuous underground wall method, excavation is carried out while protecting the collapse of the wall surface of the vertical hole by a liquid stabilizing material injected and filled into it. And a vertical hole excavation method in which the stabilizing material mixed earth and sand generated by excavation is overflowed from the upper end opening of the vertical hole and discharged, wherein the liquid stabilizing material is a bubble-containing solution, or a superabsorbent water-containing material. A vertical hole excavation method characterized in that while using either a resin solution or a mixture of the two, an additive material having a defoaming or degelling action is sprinkled on the soil mixed with stabilizing material discharged above the ground. .