JPH02153191A - Ground excavation method - Google Patents

Abstract

PURPOSE:To eliminate a gellike substance and to make the earth and sand disposable by excavating while infiltrating stabilization agent such as high water-absorbing efficiency resin solution and the like in order to prevent a hole wall from collapse and, at the same time, spraeding additive such as degelling agent to discharged earth. CONSTITUTION:Bubble agent such as surface-active agent and the like or stabilization agent of high water-absorbing resin solution such as polyacryl acid soda and the like are spouted from an excavation bit 3 through a center hole of an excavation rod 2, and is mixed with the earth in an excavation hole E1. After that, the mixed earth and sand is transferred to a hopper from a notch 1a provided on a guide pipe 1 through a collection tank 4. Then, deforming agent such as higher resin acid ester and the like or degelling agent such as CaCl2 and the like is sprayed from a sprayer 20, and bubble of stabilization agent mixed earth and sand or gellike substance is eliminated. According to the constitution, muddiness of the discharged earth and sand is prevented, it is diverted to reclamation and the like and, at the same time, it can be easily carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a ground excavation method, and particularly to a method for solving problems in processing earth and sand discharged by excavation.

(Prior art) For example, when excavating a continuous underground wall, in order to prevent the wall from collapsing, a liquid stabilizing material is injected while excavating, and the soil and sand mixed with the stabilizing material produced by the excavation are I'm trying to drain it.

The most common liquid stabilizing material is bentonite aqueous solution, and while drilling is carried out with the inside of the borehole maintained at a predetermined viscosity, the overflowing mixture of bentonite aqueous solution and excavated soil is recovered. There is.

(Problem to be solved by the invention) However, when disposing of the collected bentonite mixed soil, it is treated as industrial waste, and if it is dumped as is, the area becomes muddy, so it is difficult to dispose of it. The current situation is worrying.

The present invention takes the above problems into consideration and aims to provide a ground excavation method that allows recovered mixed earth and sand to be returned to its original state as much as possible.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention involves injecting a liquid stabilizing material to prevent the collapse of the hole wall during ground excavation, and preventing the collapse of the holes caused by the excavation. In a ground excavation method in which earth and sand mixed with a stabilizing material are discharged: As the liquid stabilizing material, either an aerated foam solution, a super water absorbent resin solution, or a mixture of the two is used; Additives with anti-foaming or gel-resolving effects were sprayed on the discharged soil mixed with the stabilizing material.

(Function) By performing drilling while injecting an aerated foam solution, gold superabsorbent resin, or a mixture of both as a stabilizing agent, the inside of the drilled hole is maintained at a predetermined viscosity, and the hole wall is held stably.

By spraying an additive having an anti-foaming or gel-resolving effect on the collected soil mixed with a stabilizing agent, air bubbles and/or gel-like substances in the mixed soil disappear, leaving the soil as a single substance containing water.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

The figure is an explanatory diagram showing a ground excavation method used in constructing cast-in-place piles and continuous underground walls according to the present invention.

In this construction method, excavation ground E is excavated using an excavation rod 2 using a guide vibrator 1 installed on the ground surface as a guide.

The above-mentioned stabilizing material is ejected from the drilling bit 3 at the tip of the drilling rod 2 through the center thereof, and mixes with the excavated earth and sand in the drilling hole E1.

The stabilizing material-mixed earth and sand passes through a notch 1a formed on one side of the guide vibe 1, overflows into a collection tank 4 installed on the side, and is stored there.

The mixed earth and sand is then fluidly transferred to a closed earth and sand hopper 6 through the vibrator 5, and sequentially transferred from this hopper 6 to a dump truck 7 located below.

The mixed earth and sand stored in the recovery tank 4 is sprayed with an antifoaming agent and/or a gelling agent by a sprayer 20 in order to eliminate them.

Furthermore, by connecting the earth and sand hopper 6 to a vacuum pump 8 and suctioning it, it is possible to promote the disappearance of air bubbles remaining in the mixed earth and sand.

The ground to which the above excavation method can be applied is particularly effective for ground with the following soil types.

■Soil with a fine grain content of 15% or less.

■Gravel ground with a trace amount of fine particles.

■Gravel ground with fine grain content of several percent to 1,526.

Next, a specific example 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 drilling hole E1 from the tip of the drilling bit 3.

Foaming agents include surfactants and protein-based foaming agents, and a thickener may be added as appropriate to strengthen the foam.

Due to foaming, the apparent viscosity inside the borehole El is 2000 to 1.
0,000 cps, and while the excavated soil is mixed and dispersed within the bubbles, the hole wall is kept stable due to its apparent viscosity and the presence of a mixture with a high specific gravity.

As for the amount of the foaming agent added, it is preferable to add about 1 to 3 parts per 100 parts of water when the above-mentioned foaming ratio is achieved.

Specific devices for creating bubbles include a stirring mixing tank 9 and a pump 10 for mixing water and a foaming agent as shown in the figure.
, a hose 11, an air compression pump 12, and a foamer 13 connected to the middle of the hose 11. By blowing high-pressure air generated by the compression pump 12 into the foamer 13, the foaming agent solution foams. Hose 1 in condition (aerated foam solution)
It is injected from the tip of the drilling bit 3 through the drilling rod 2 from the tip of the drilling bit 5 .

In addition, the air-containing foam sediment that overflowed to the ground side is collected in the collection tank 4.
The air bubbles are removed by spraying an antifoaming agent, and the soil becomes moist soil.

A water supply is created when the bubbles disappear, making it easy to separate soil and water.

Antifoaming agents include higher fatty acid esters and mineral oil.

Higher alcohols are used. The amount of spraying may be about 20 to 80 cc per 100 ON of recovered mixed earth and sand, taking economic efficiency and defoaming properties into consideration.

In addition, if a thickener is added, the amount used is 1150~
It is recommended to add 1/200 of the enzyme agent to the antifoaming agent and spray it.

(b) When a single super absorbent resin solution is used as a stabilizer: A super absorbent resin is mixed with water to increase its viscosity, and this is supplied into the excavation hole El from the tip of the excavation bit 3.

Super absorbent resin includes sodium polyacrylate.
0.4 to 0 per 100 parts of water depending on the soil quality of the excavated ground
．． Add about 7 parts and adjust the viscosity to 1000~+0000cps
By adjusting this, the hole wall can be kept stable.

As an apparatus for producing a super absorbent resin solution, it is possible to use an apparatus obtained by removing the compression pump 12 and the foamer 13 from the illustrated apparatus.

The mixed earth and sand that has overflowed to the ground side is transferred to the inside of the collection tank 4, and is further sprayed with a gel-resolving agent by the sprayer 20, so that its viscosity is reduced and it becomes earth and sand containing water.

As gel-resolving agents, Ca C1), Ca (OH
) 2 and other salts are used. The amount of spraying is about 4 to 7 kg per 10,100 O of mixed soil and sand collected.

(c) When using a mixture of air-containing foam and a super absorbent resin solution as a stabilizer: Add the above-mentioned super absorbent resin to water and adjust the viscosity to 1000~
After adjusting to +0000 cps, a small amount of foaming agent is mixed, the foam is foamed 165 to 4 times by stirring, etc., and the foam is supplied from the tip of the drilling bit 3 into the drilling hole El.

The apparent viscosity inside the borehole El is 1500 to 6000 due to the thickening effect of the super absorbent resin and foaming caused by the foaming agent.
0 cps, keeping the hole wall stable while mixing and dispersing the excavated soil into the foam.

In this example, since the thickened solution is foamed, the film of the bubbles is strengthened and it takes a longer time to disappear, so that the pore walls can be roughly stabilized.

Further, the air-containing bubbles and superabsorbent resin mixed earth and sand that have overflowed to the ground side are transferred to the recovery tank 4, where they are dissolved by dispersing an additive and the air bubbles disappear.

As the air bubbles disappear, a water channel is created for the water contained in the earth and sand, making it easier to separate it from the earth and sand.

As an antifoaming and degelling agent, CaC1) is used as mentioned above.
, Ca(OH)2, and other salts are used.

The amount of spraying is determined by considering economic efficiency, gel-resolving properties, and anti-foaming properties.
Approximately 4 to 7 kg is sufficient for the collected mixed earth and sand.

(Effects of the Invention) As described above in detail with reference to the embodiments, in the present invention, excavation is carried out while injecting an aerated foam solution, a gold superabsorbent resin, or both as a stabilizing agent. The inside of the hole is maintained at a predetermined viscosity, and the viscosity is maintained at a predetermined level.
Hydraulic conductivity of the order of 6cIIl/s and slump value of 5~
While maintaining the pore wall stably by ensuring fluidity of 20cm, air bubbles in the mixed soil are dispersed by spraying additives with anti-foaming or gel-resolving properties while collecting the stabilizer-mixed soil. And/or the gel-like substance disappears and becomes soil containing water.

Therefore, in the ground excavation method of the present invention, compared to the conventional ground excavation method using bentonite as a stabilizing material, there is no siltation in the dumped state, the disposal of the discharged soil is easy, and the discharged soil can be diverted to landfill, etc.

[Brief explanation of the drawing]

The figure is an explanatory diagram showing the ground excavation method according to the present invention.

Claims (1)

[Claims] (1) In a ground excavation method in which a liquid stabilizing material is injected to prevent the hole wall from collapsing during ground excavation, and the soil mixed with the stabilizing material produced by the excavation is discharged: As a liquid stabilizing material, either an aerated foam solution, a superabsorbent resin solution, or a mixture of the two is used, and the stabilizing material is added to the soil discharged onto the ground to have a defoaming or gel-resolving effect. A ground excavation method characterized by scattering wood.