JPH0873842A - Slurry for dug hole in ground - Google Patents

Abstract

PURPOSE: To obtain a slurry for a dug hole in ground without inducing any rottenness or deterioration even in mixing with salts-containing water, sea water or cement, etc., as a stabilizing liquid used in the dug hole to stabilize the ground-digging hole. CONSTITUTION: This slurry for a dug hole in ground is composed of 100 pts.wt. of siliceous aqueous jelly particles having particle diameter of 1-300μm and an SiO2 content of 1-20wt.% and 20-200 pts.wt. of water and has a viscosity of 50-10000mPa.s at 20 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel drill hole stabilizing liquid for use when excavating the ground from the surface of the earth to the ground for storage in the drill hole formed by this drilling.

[0002]

2. Description of the Related Art In civil engineering, an underground continuous wall made of concrete is often provided from the surface of the earth to the underground. This underground continuous wall made of concrete is constructed by inserting a cage made of reinforcing steel into an excavation hole provided in the ground from the surface of the earth to the ground, and pouring uncured concrete and hardening it. .

This ground excavation hole has a vertical length of 1 to 1.
It has a diameter of 2 meters and a few meters in width, and has a depth of about 20 meters underground, and is usually formed by excavation using a bucket-type or rotary-type excavation machine. However, such a deep drill hole is generally prone to collapse due to earth pressure from its surroundings, and in some cases groundwater may flow into the drill hole or gas may be ejected into the drill hole to collapse. is there.

Therefore, in order to stabilize such an unstable drill hole, an aqueous liquid called a stabilizing liquid is stored in the drill hole during the drilling and after the drilling until the setting of uncured concrete. Is done. In the excavation using this stabilizing solution, after the excavation was started at the initially set constant diameter, the excavated soil was carried through the discharge pipe to the ground outside the excavation hole, and the excavated holes formed were The stabilizing solution is supplied so that the drill hole is filled with the stabilizing solution. After the completion of the excavation, the uncured concrete that is placed in the drill hole is placed so as to fill the drill hole with the uncured concrete in the upward direction from the bottom of the drill hole. A stabilizing solution corresponding to the volume of the uncured concrete supplied is successively discharged from the drill hole to the outside and collected. This recovered stabilizing solution is repeatedly used for another excavation.

Conventionally, as a stabilizing solution for such a ground excavation hole, a solution in which clay such as bentonite is dispersed in water, a solution in which a water-soluble polymer substance such as carboxymethyl cellulose or methyl cellulose is dissolved in water, and dissolved bentonite are dissolved. Although a liquid containing a polymer substance has been widely used, some improved stabilizing liquids have been proposed. For example, in Japanese Examined Patent Publication No. 52-27923, a resin composition consisting of a dispersion medium, an inorganic powder, a water-soluble polymer substance and a polymer suspension is prepared between a stabilizer containing bentonite-containing muddy water and fresh concrete. A method for preventing gelation of bentonite-containing muddy water caused by contact with fresh concrete by using it as a shielding liquid is disclosed.

Japanese Patent Publication No. 57-25585 discloses that 100 parts of water or seawater, 0.5 to 30 parts of inorganic clay and 0.05 to 5 parts of
An excavation method is disclosed which uses mud containing carboxymethyl cellulose having a degree of substitution of 1.1 to 2.5 and in which deterioration is suppressed. Japanese Unexamined Patent Publication (Kokai) No. 64-29488 discloses a sodium salt of an unsaturated carboxylic acid polymer having a degree of polymerization of 5000 or less, an aluminate such as sodium aluminate, a metal oxide such as magnesium oxide, and a compound such as sodium alum. An additive for suppressing the deterioration of a stable solution containing an inorganic clay such as bentonite or a stable solution containing a water-soluble polymer, which comprises a salt or a specific compound such as a complex salt such as a salt of ethylenediaminetetraacetic acid, is disclosed.

Further, JP-A-5-17763 discloses that by adding welan gum to a bentonite-containing stabilizing solution, deterioration of the stabilizing solution due to groundwater, seawater, cement or the like is suppressed.

[0008]

A stable liquid consisting of an aqueous dispersion of bentonite has the viscosity required for this stable liquid due to bentonite swollen with water, but is contained in soil, groundwater, seawater, concrete, etc. Since it deteriorates due to gelation due to metal ions, it can be reliably deteriorated when used in drilling holes in coastal areas where it is easy to come into contact with seawater, as a stabilizer that uses seawater as kneading water, and when it comes into contact with concrete. Cause

Addition of carboxymethyl cellulose having a high degree of substitution described in JP-B-57-25585 is effective for suppressing deterioration of bentonite-containing stabilizing solution due to mixing of seawater, but in contact with concrete, The stabilizing solution is less effective in suppressing deterioration. In the above-mentioned JP-A-64-29488, an additive consisting of a salt of a low degree of polymerization unsaturated carboxylic acid polymer and a specific compound is a bentonite-containing stabilizing solution against the inclusion of cement or a small amount of seawater. However, when a large amount of seawater is mixed, the deterioration suppressing effect is poor, and seawater cannot be used as kneading water.

In the method of using the shielding liquid described in Japanese Patent Publication No. 52-27923, the work of injecting two liquids of the stabilizing liquid and the shielding liquid into the excavation hole and the recovery of the stabilizing liquid and the shielding liquid separately. It requires work and is complicated. According to the above-mentioned JP-A-5-17763, a mud water regulator mainly composed of welan gum is effective in suppressing deterioration of bentonite-containing stabilizers due to mixing of groundwater, seawater, cement, etc., but deterioration due to decay It tends to occur and also deteriorates the bentonite-containing stabilizer.

As described above, various improvements have been made to the bentonite-containing stabilizer, but a sufficient solution has not been obtained yet. The present invention is intended to provide a novel stabilizing solution for ground drilling holes, which is basically non-deteriorating and does not deteriorate even when it comes into contact with salt-containing water, seawater, cement, etc. and does not rot. To do.

[0012]

The ground excavation hole stabilizing solution of the present invention comprises 100 parts by weight of siliceous aqueous jelly particles having a SiO ₂ content of 1 to 20% by weight and a particle size of 1 to 300 microns and 20 parts of water.
~ 200 parts by weight and 50-1000 at 20 ° C
It has a viscosity of 0 mPa · s. The siliceous aqueous jelly can be easily obtained by a known method. Preferred examples thereof include a method of adding various acids or salts, for example, sulfuric acid, hydrochloric acid, nitric acid, acetic acid, citric acid, salt, magnesium sulfate, etc. to an aqueous solution of a water-soluble silicate such as water glass, water-soluble silicic acid such as water glass. A method of gelling an aqueous solution of silicic acid or a low-polymerization degree polymer thereof obtained by decationizing an aqueous solution of a salt, or further neutralizing an aqueous silica sol by adding an acid or an alkali, or adding a salt to an aqueous silica sol. Examples thereof include a method of adding and gelling. These siliceous aqueous jellies are usually obtained in the form of lumps, and contain 1 to 20% by weight, preferably 2 to 10% by weight, of silica content such as colloidal silica in the gel state, silicic acid and its low degree of polymerization polymer as SiO _2. To do. And this jelly can contain arbitrary other components, as long as the objective of this invention is achieved.

The siliceous aqueous jelly particles having a particle size of 1 to 300 μm can be obtained by crushing a lumpy siliceous aqueous jelly, for example, as described in JP-A-6-148827. The crushing is carried out by subjecting the jelly to a physical external force sufficient to bring about its destruction, whereby the crushing breaks down the jelly to a size of 1 to 300 microns. Crushing to bring about such fine division can be carried out, for example, by applying strong stirring such as a homogenizer to jelly at room temperature.

The ground excavation hole stabilizing solution of the present invention is obtained by directly crushing the above-mentioned massive siliceous aqueous jelly as described above without adding water to the siliceous aqueous jelly.
20-200 parts by weight, preferably 50-100, relative to 0 parts by weight
By adding 20 parts by weight of water and mixing uniformly, or by adding 20 to 200 parts by weight, preferably 50 to 100 parts by weight of water to 100 parts by weight of the lumpy siliceous aqueous jelly. It is obtained by crushing this jelly as described above. The added water is not particularly limited, and for example, normal water such as river water, lake water, well water, and tap water, as well as sea water can be used. The ground drilling hole stabilizing liquid of the present invention may contain any other component as long as the object of the present invention is achieved.

The ground drilling hole stabilizing solution of the present invention has a viscosity of 50 to 10,000 mPa · s at 20 ° C. This viscosity can be easily measured using, for example, a B-type viscometer.

[0016]

When the ground excavation hole stabilizing solution of the present invention is injected into the excavation hole, this stabilizing solution containing fine jelly particles permeates into the ground from the wall surface of the drilling hole, and the soil particles in the ground are absorbed. The siliceous aqueous jelly particles in the stabilizing solution adhere to form a water impermeable layer near the wall of the borehole, and this water impermeable layer alters the collapsibility of the ground near the wall of the borehole. It is thought to be strengthened by doing.

Since the ground drilling hole stabilization liquid of the present invention is essentially an aqueous dispersion of siliceous aqueous jelly particles,
Even if salts derived from seawater, cement, etc. are mixed into this stabilizing solution, it is stable without an increase in viscosity or material separation. As the particles of the siliceous aqueous jelly, the lower the SiO ₂ content, the more cost effective, and it is not preferable to use the jelly having a SiO ₂ content as high as 20% by weight or more. However, it is difficult to prepare a siliceous aqueous jelly having a low SiO ₂ concentration such that the SiO ₂ content is less than 1% by weight.

If the particle size of the siliceous aqueous jelly particles is less than 1 micron, the stabilizing solution containing such particles easily penetrates deep into the ground. It is difficult to form an impermeable layer which is preferable only for On the contrary, if the particle size of the siliceous water-based jelly particles is 300 μm or more, such particles have poor adhesion to the soil particles on the wall surface of the borehole, and it is difficult to form a preferable impermeable layer near the wall surface of the borehole. Let's train.

When the viscosity of the ground drilling hole stabilizing liquid is 50 mPa · s or less, such a stabilizing liquid easily penetrates from the wall surface of the drilling hole to the deep part of the ground, and it is difficult to form an impermeable layer near the wall surface of the drilling hole. . However, the viscosity of the ground drilling hole stabilization liquid is 10,000 mPas
If it is higher than the above value, it becomes difficult to perform pumping for supplying such stabilizing liquid into the drill hole or discharging it from the drill hole to the outside.

A ground excavation hole stabilizing solution containing the above siliceous aqueous jelly particles is added to 100 parts by weight of the jelly particles.
When it contains 20 parts by weight or less of water, such a stabilizing solution tends to have a viscosity at 20 ° C. of more than 10,000 mPa · s. However, when the ground excavation hole stabilizing solution containing the siliceous water-based jelly particles contains 200 parts by weight or more of water based on 100 parts by weight of the jelly particles, the resulting stabilizing solution contains water and the particles. Easy to separate.

[0021]

【Example】

Example 1 As described below, the ground excavation hole stabilizing liquid (G ₁ ) to (G _1
3 ) and a ground excavation hole stabilizing solution (G ₄ ) of Comparative Example were prepared. (G ₁ ): By adding sulfuric acid and tap water to a commercially available alkaline aqueous silica sol having a SiO ₂ concentration of 30% by weight,
After adjusting the pH of the sol to 6.5 and the SiO ₂ concentration to 5% by weight, the sol was left at room temperature to obtain an aqueous jelly. Next, 50% by weight of tap water was added to the aqueous jelly, and the mixture of jelly and water was stirred for 5 minutes at 3000 rpm using a homogenizer. A ground excavation hole stabilizing solution (G ₁ ) consisting of an aqueous dispersion of the above jelly particles having a diameter was obtained.

(G ₂ ): The pH of the sol was adjusted to 6. by adding sulfuric acid and seawater to the commercially available alkaline aqueous silica sol.
After adjusting the SiO ₂ concentration to 5 and the SiO ₂ concentration to 5 wt%, the sol was left at room temperature to give an aqueous jelly. Then, 50% by weight of seawater was added to the aqueous jelly, and the mixture of jelly and water was stirred for 5 minutes at 3000 rpm using a homogenizer.
A ground drilling hole stabilization liquid (G ₂ ) was obtained which consisted of an aqueous dispersion of the above jelly particles having an average particle size of 0 micron.

(G ₃ ): The pH of the sol was adjusted to 6.5 and the SiO ₂ concentration was adjusted to 5% by weight by adding sulfuric acid and tap water to commercially available JIS No. 3 water glass, and the sol was cooled to room temperature. When left to stand, an aqueous jelly was obtained. Then, after adding 50% by weight of tap water to the aqueous jelly, the mixture of the jelly and water was mixed with a homogenizer at 3000 rp.
After stirring for 5 minutes at a rotational speed of m _{3, a} ground drilling hole stabilizing solution (G ₃ ) consisting of an aqueous dispersion of the above jelly particles having an average particle size of 100 microns was obtained.

(G ₄ ): Commercial bentonite (Kunigel V
By dispersing 1) in tap water, a ground excavation hole stabilizing solution (G ₄ ) containing 8% by weight of bentonite was obtained. Example 2 In this example, the viscosity of the drilling hole stabilizing liquids (G ₁ ) to (G ₄ ) and the amount of filtered water were measured.

The viscosity was measured using a B-type viscometer and
It was carried out by measuring the viscosity (mPa · s) of the liquid at a rotation speed of 12 rpm with a No. 1 rotor at ℃. The amount of filtered water is measured by American Petroleum Institut
e) Using a filtration tester conforming to the standard, place the filter paper of Toyo Filter Paper No. 4 on the bottom of the cylinder with an inner diameter of 76.2 mm, and then put 500 ml of the above stabilizing solution for drilling holes into this cylinder to obtain 3 kg / The measurement was performed by measuring the amount of water (ml) filtered until 30 minutes had elapsed after starting the pressurization with nitrogen gas of cm ² .

The measurement results are shown in Table 1. Example 3 In this example, 1 part by weight of ordinary Portland cement was added to 100 parts by weight of the drill hole stabilizing solution, mixed well, and allowed to stand for 1 day. Was measured. The measured values are shown in Table 1.

Example 4 In this example, 2 parts by weight of seawater was added to 100 parts by weight of the drill hole stabilizing solution, mixed well, and allowed to stand for 1 day. Was measured. The measured values are shown in Table 1. Table 1 Stabilizing solution implementation example 2 implementation example 3 implementation example 4 No. Viscosity water filtration viscosity water filtration viscosity water filtration _{(G 1) 250 35 265 36} 270 38 (G 2) 245 30 250 32 256 34 (G ₃ ) 250 32 265 35 250 39 (G ₄ ) 255 33 No No 920 120 In Example 3, neither the viscosity nor the amount of filtered water could be measured because the entire ground drilling hole stabilization liquid of (G ₄ ) gelled. there were. From the above Examples 3 and 4, it is recognized that the ground excavation hole stabilizing solution of the present invention is hardly affected by the mixing of seawater or the mixing of Portland cement.

Example 5 In this example, instead of directly providing a drill hole in the ground, a soil layer corresponding to the ground is formed on a filter paper, and the drill hole stabilizing solution of the present invention is stored thereon under pressure. Thus, a water-impermeable layer was formed on the surface layer of the soil layer. Kanto bentonite as soil for use in soil layers
SAM Clay (trade name) manufactured by K.K. was prepared, and water was added thereto to prepare soil having a water content ratio of 30% by weight.

Separately, in the preparation of (G ₁ ) above, 5% by weight of Si
To the silica sol adjusted to the O ₂ concentration, 50 weight ppm of the food additive Red No. 108 reagent was added to this sol (G
_A ground excavation hole stabilizing solution (G ₅ ) composed of an aqueous dispersion of jelly particles colored in red was prepared in the same manner as in the preparation of ₁ ). Then, using a filter tester according to the above-mentioned American Petroleum Institute standards, after placing Toyo filter paper No. 4 filter paper on the bottom of the cylinder, the soil prepared by filling the filter paper with a thickness of 5 cm was prepared. Layers were formed. Onto this soil layer, 300 ml of the drill hole stabilizing solution (G ₅ ) was added, and the drill hole stabilizing solution (G ₅ ) was stored for 3 hours under pressure with 3 kg / cm ² of nitrogen gas. However, filtered water was not obtained.

Then, from the filtration tester, a drill hole stabilizing solution was prepared.
(G ₅ ) was discharged and the soil layer was taken out. When the soil layer was cut in the depth direction and the cross section thereof was visually observed, a red-colored layer was formed at a depth of 0.5 cm from the surface.

[0031]

[Effect] The ground excavation hole stabilizing solution of the present invention is used for groundwater, seawater,
Does not cause deterioration due to the mixture of cement,
The performance can be maintained even after repeated use.
100 parts by weight of siliceous aqueous jelly particles having a SiO ₂ content of 1 to 20% by weight and a particle size of 1 to 300 μm, utilizing the property of siliceous aqueous jelly particles that do not deteriorate even when mixed with seawater. And seawater or mixed water of this and normal water
20 to 200 parts by weight, and 50 to 10 at 20 ° C.
A liquid having a viscosity of 000 mPa · s can be used as the ground drilling hole stabilizing liquid of the present invention. Further, the ground excavation hole stabilizing liquid of the present invention can be repeatedly used for ground excavation work in coastal areas where seawater is easily mixed with the ground excavation hole stabilizing liquid.

When the ground excavation hole stabilizing liquid of the present invention stored in the excavation hole is replaced with the pouring concrete, a part of the ground excavation hole stabilizing liquid of the present invention may be mixed into the pouring concrete. However, since the jelly particles in this stabilizing solution do not affect the hydration reaction of cement, they do not affect the setting and strength development of concrete. Since the siliceous water-based jelly particles in the ground drilling hole stabilizing solution of the present invention do not have swelling property, excavated soil mixed with a part of the ground drilling hole stabilizing solution discharged during ground drilling is treated normally. , Especially can be subjected to disposal.

Claims (1)

[Claims] 1. A composition comprising 100 parts by weight of siliceous aqueous jelly particles having a SiO ₂ content of 1 to 20% by weight and a particle size of 1 to 300 microns and 20 to 200 parts by weight of water, and at 20 ° C.
Ground drilling hole stabilization liquid with a viscosity of 50 to 10,000 mPa · s.