JPH10298393A - Additive for stable liquid engineering method excellent in resistance to cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject additive capable of exhibiting excellent resistance to cement, etc., by including Na-carboxymethyl cellulose and/or a specific anionic polymer and a specific amphoteric ion. SOLUTION: This additive consists essentially of (A) Na-carboxymethyl cellulose or/and an anionic polymer containing three kinds of recurring structures of formulas I to III [R1 is C(CH3 )2 CH2 , etc.; R2 and R3 are each H, CH2 CH2 -OH, etc.; M1 and M2 are each H, Na or K] at a ratio of 0.5-15 wt.% formula I, 13-50 wt.% formula II and 40-85 wt.% formula III based on total structural units and (B) an amphoteric ion containing three kinds of recurring structures of formulas IV to VI at a ratio of 5-40 wt.% formula IV, 20-65 wt.% formula V and 10-50 wt.% formula VI based on total structural units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stable solution containing an amphoteric ionic polymer as a stable liquid for excavation (hereinafter, referred to as a stable liquid) used for a method of excavating civil works (hereinafter, referred to as excavation) for underground continuous walls, underground piles, and the like. It is concerned with the improvement of additives for liquid method.
More specifically, the present invention relates to an additive for a stabilizing solution method which is remarkably superior in cement resistance to Na-carboxymethylcellulose which has been conventionally used as an important essential component of the stabilizing solution.

[0002]

2. Description of the Related Art At present, in excavation of underground continuous walls, underground piles, etc., muddy water is generally used as a stabilizing liquid (generally referred to as a stabilizing liquid in civil engineering.
Stabilizing solution) is used, but by using a stabilizing solution having an appropriate specific gravity (generally 1.10 or less) and wall-forming ability, it is possible to stably maintain the inside of the excavated bare pit,
Since it can be easily replaced with reinforced concrete, good continuous walls and piles are formed.

[0003] The composition of a commonly used stabilizing solution is 2 to 8 g of bentonite per 100 ml of fresh water and Na-carboxymethylcellulose (generally abbreviated as CMC).
(Hereinafter referred to as CMC) 0.05 to 0.5 g, and CMC is a very important component of the stabilizer composition used for imparting viscosity and wall forming property to the stabilizer. Here, the wall forming function generally has a dewatering amount (unit: ml) and a wall thickness (unit: mm) for 30 minutes under a pressure of 3 kg / cm ² by a dehydration test according to API standards (American Petroleum Institute standards). Has been evaluated by. In addition, it is considered that a stable liquid with less dewatering amount and a thinner and more durable wall has a better wall forming function, but in the civil engineering area, if the dewatering amount is 20 ml or less or the thickness of the mud wall is 1 mm or less, it will It is a stable liquid having good wall-forming properties.

[0004] The main purpose of using CMC as a component of the stabilizing solution composition is to reduce the amount of dehydration and to make the mud wall thin. Various CMCs have been used to achieve this goal. CMC with a substitution degree of 0.6 to 0.8 is inexpensive but inferior in salt resistance, cement resistance and stability. In comparison, the CMC with the degree of substitution increased to 1.2 to 1.5 has much better salt resistance and cement resistance than the CMC with a lower degree of substitution. In recent excavation works of underground diaphragm walls and underground piles, there are many works of excavating ground and concrete parts improved with cement, lime and the like. Therefore, CMC having a high degree of substitution of 1.2 to 1.5 as a CMC having high cement resistance, for example, RB-35 manufactured by Daicel Chemical Industries, Ltd.
Currently, a so-called polymer stabilizer in which the amount of bentonite added to 100 ml of water is reduced to 2 to 3 g and 0.2 to 0.3 g of high quality CMC such as RB-35 is added is generally used. I have.

A stabilizer using such a high-quality CMC having a high degree of substitution has higher salt resistance and cement resistance than a conventionally used stabilizer using a general CMC having a degree of substitution of 0.6 to 0.8. Is also excellent. However,
If the cement content increases, for example, if the cement solid content is 1.0% (weight / volume) or more, the stable liquid itself gels and loses fluidity, and the amount of dehydration is remarkably large. Impossible. This trend is
It becomes more remarkable as the amount of solid content in the stabilizing liquid increases due to mixing of excavated soil.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies and found that Na-carboxymethylcellulose and / or the following polymer (A) and the following zwitterionic polymer (B ) And the additive for stabilizing liquid method reduces cement solid content by 1.0% (weight / volume)
Even if mixed above, it does not cause gelation, the amount of dehydration is small,
It was found that the mud wall was also thin and showed good functions.

Anionic polymer (A): Three types of repeating structural units represented by the following formulas X ₁ , X ₂ , and X ₃ , wherein X ₁ is 0.5 to 15% by weight and X ₂ is 13 to 50 in all structural units. wt%, the polymer X ₃ is contained in an amount of 40 to 85 wt%.

[0008]

Embedded image

(Wherein R ₁ represents —C (CH ₃ ) ₂ CH ₂ — or any organic functional group.

R ₂ and R ₃ are a hydrogen atom or —CH ₂ CH ₂ —OH
Or both represent any organic functional group.

M ₁ and M ₂ represent a hydrogen atom, sodium or potassium. ) Zwitterionic polymer (B): Three kinds of repeating structural units represented by the following formulas Y ₁ , Y ₂ and Y ₃ are represented by Y _{1 in} all structural units.
There 5 to 40 wt%, Y ₂ is 20 to 65 wt%, the polymer Y ₃ is contained in an amount of 10 to 50 wt%.

[0012]

Embedded image

(Wherein R_Four~ R₆Is a hydrogen atom, an alkyl group
Or an alkenyl group, A^-Is Cl^-Or Br^- Represents

M ₃ represents sodium, potassium, calcium or magnesium. That is, the present invention is directed to a stable liquid construction method comprising, as essential components, Na-carboxymethylcellulose or / and the anionic polymer (A) shown above and the zwitterionic polymer (B) shown above as essential components. The present invention relates to an additive, a drilling stabilizer using the additive, and a civil engineering drilling method using the drilling stabilizer.

As described above, when only CMC is used, if the cement is mixed in a solid content of 1.0% (weight / volume) or more, gelation occurs completely, and the amount of dehydration increases remarkably. Also, the mud wall becomes thicker. When only the anionic polymer (A) is used, when the cement mixing amount is small, the wall forming property is excellent and the dewatering amount is small,
Mud walls are thin and durable. But as cement solids
When 1.5% is mixed, a soft gel is formed, and the degree of gelation is smaller than that of CMC. In addition, the amount of dehydration increases, and the wall forming property is lost. When only the amphoteric ionic polymer (B) is used, gelation does not occur, but the amount of dehydration is large, the mud wall is thick, and no good wall forming function is exhibited. However, it has been found that when Na-carboxymethylcellulose or / and the above-mentioned anionic polymer (A) and the above-mentioned zwitterionic polymer (B) are used in combination, remarkably good properties can be obtained.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The additive for a stable liquid method of the present invention contains Na-carboxymethylcellulose or / and the above anionic polymer (A) and the above zwitterionic polymer (B) as essential components. Is done.

As the anionic polymer (A) of the present invention, those satisfying the following characteristic values can be used as preferred polymers. 1% by weight aqueous solution viscosity: 50 to 550 cps (B-type viscometer, 25 ° C.) Weight average molecular weight: 1 × 10 ^{6 to} 3 × 10 ⁶ (polyethylene oxide equivalent molecular weight) Number average molecular weight: 2 × 10 ^{5 to} 6 × 10 ⁵ (Molecular weight in terms of polyethylene oxide) As the zwitterionic polymer (B) of the present invention, those satisfying the following characteristic values can be used as preferable polymers. 1% by weight aqueous solution viscosity: 2 to 20 cps (B-type viscometer, 25 ° C.) Weight average molecular weight: 1 × 10 ^{4 to} 5 × 10 ⁴ (polyethylene oxide reduced molecular weight) Number average molecular weight: 0.5 × 10 ^{4 to} 3 × 10 ⁴ (Molecular weight in terms of polyethylene oxide) In the present invention, the cement resistance is improved in any case if the degree of substitution of the CMC used is 0.6 or more, but the CMC with the degree of substitution of 1.0 or more has improved cement resistance. Preferred for CMC having a degree of substitution of 1.5 or more is preferable because the mud wall is strong and good. The viscosity of the CMC used depends on the desired viscosity of the stabilizer, but is generally 1%.
The aqueous solution viscosity is preferably 10 to 1000 cps (B-type viscosity, 60 rpm, 25 ° C.).

In the present invention, the combination ratio of CMC and / or anionic polymer (A) and amphoteric ionic polymer (B) is 30/70 to 70/30 (weight basis) for gelling. It is preferable because it does not occur and shows a function excellent in cement resistance. More preferably, it is 40/60 to 60/40.

The additive for a stable liquid method according to the present invention can be used not only for civil engineering but also for excavating hot spring wells, water wells, geothermal wells, oil and natural gas wells, and the like.

[0020]

Next, the present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 To 3000 ml of fresh water, 90 g (3% (weight / volume)) of bentonite TB300 of Tachibana Material Co., Ltd. was added and 5000 rpm.
After stirring for 20 minutes at room temperature, the mixture was allowed to stand for 24 hours to prepare a fully hydrated bentonite suspension. This bentonite suspension 3000
Cell base mud manufactured by Daicel Chemical Industries, Ltd. for ml
RB-35 (trade name of Na-CMC, degree of substitution: 1.52, viscosity: 249
Add 9 g (0.3% (weight / volume)) of cps (1% by weight aqueous solution, B-type viscometer, 60 rpm, 25 ° C.), water: 4.8%) and add 500 g
The mixture was stirred at 0 rpm for 20 minutes, and 600 ml of the polymer stable liquid was collected in five containers. Add 50g of Portland cement to 100ml of Shimizu and use a magnetic stirrer to
The mixture was stirred for 5 hours to prepare a cement slurry. 1 g of this cement slurry contains about 0.333 g of cement solids. Next, 9 g, 14.4 g, 18 g, and 27.3 g of the cement slurry were added to 600 ml of the four polymer stabilizing solutions, respectively.
The mixture was added, stirred at 5,000 rpm for 10 minutes, and allowed to stand for 24 hours. Two
After standing for 4 hours, the state of the stable solution was visually observed and again stirred for 5 minutes at 5000 rpm to obtain a funnel viscosity (FV, sec.
00 ml / 500 ml), apparent viscosity (AV, cps), plastic viscosity (PV, cps), yield value (YV, lb / 100 ft ² ), gel strength (Gel, lb / 100 ft ² ), dehydration amount (FL, m
l) and mud wall (MC, mm) were measured respectively. At the same time, the properties of the base polymer stabilizer without added cement slurry were also measured. Table 1 shows the results.

The methods for measuring various properties are described below. 1. Funnel Viscosity (FV, sec, 500 ml / 500 ml) The time (sec) of putting 500 ml of a stabilizing solution into a funnel viscometer and flowing out 500 ml is called funnel viscosity.

2. Apparent viscosity (AV, cps) Measured with a 6-speed fan VG meter Model 35 rotated by a periodic motor. This corresponds to half the value of 600 rpm reading.

3. The plastic viscosity (PV, cps) measurement device is the same as the one used for the measurement of apparent viscosity.
It corresponds to the value obtained by subtracting the 300 rpm reading from the 0 rpm reading. The solids contained in the stabilizing solution exhibit flow resistance caused by mechanical friction.

4. Yield value (YV, lb / 100ft ² ) The measuring instrument is the same as that used in the measurement of apparent viscosity, and is 30
It corresponds to the value obtained by subtracting the plastic viscosity from the reading at 0 rpm. When the fluid is in a flowing state, it means the shear force required to continue the flow.

[5] Gel strength (Gel, lb / 100ft)
² ) The measuring device is the same as that used for the measurement of apparent viscosity.
Equivalent to rpm reading. It means the shear force required to start the flow of the fluid from rest.

6. Dehydration amount (FL, ml) The amount of water drained when a pressure of 3 kg / cm ² G is applied at room temperature for 30 minutes using a filtration tester according to API standards.
It is an indicator of mud wall formation.

7. Mud wall (MC, mm) The measuring device is the same as that used in the measurement of the amount of dehydration. After the measurement of the amount of dehydration, the thickness of the mud wall adhering to the filter paper is measured.

[0029]

[Table 1]

Table 1 shows the effect of cement contamination on the polymer stabilizing solution. As is clear from Table 1, when the cement solid content is 0.5%, even if cement is mixed, almost no cement is mixed. Although it is not contaminated, when the cement content is 0.8%, the yield value increases, gelation occurs, the amount of dehydration becomes three times or more, and the mud wall becomes thick. Further, when the cement content is 1.0% or more, gelation increases and the amount of dehydration increases remarkably, making it unusable.

When the cement solid content is 1.0% or more, C
The phenomenon that the protective colloid function by the MC is destroyed and the polymer stabilizer causes gelation and the amount of dehydration increases remarkably also in other CMCs used in civil engineering. Table 2
Indicates the results of testing on other CMCs. The measurement conditions were the same as those in Example 1 in which the amount of cement slurry added was 27.3 g / 600 ml.

[0032]

[Table 2]

As is clear from Table 2, the current good CMC
CMC, which is generally used as the above, loses the protective colloid function completely when 1.5% of cement solids are mixed.

Example 2 In the same manner as in Example 1, a bentonite suspension (3% (weight / volume)) was prepared. 600ml of this bentonite suspension
In a container, the weight average molecular weight is 2 × 10 ⁶ (molecular weight in terms of polyethylene oxide), the number average molecular weight is 4.1 × 10 ⁵ (molecular weight in terms of polyethylene oxide), the pH is 10.5 (1% by weight aqueous solution), and the viscosity is 150 cps (1 Weight% aqueous solution, B-type viscometer, 60 rpm, 25 ° C.), represented by the following formula in all structural units: X ₁ is 5% by weight, X ₂ is 32% by weight, X ₃ is 63% by weight
1.8 g (0.
3% (weight / volume)) and stirred at 5000 rpm for 10 minutes to prepare a stable liquid. To this stable solution, 27.3 g / 600 ml of cement slurry (1.5% cement solid content) prepared in the same manner as in Example 1 was added, stirred at 5,000 rpm for 10 minutes, and allowed to stand for 24 hours. After standing for 24 hours, the state of the stable solution was visually observed, and the mixture was again stirred at 5,000 rpm for 5 minutes, and FV, AV, P
V, YV, Gel, FL, and MC were measured. Table 3 shows the results.

[0035]

Embedded image

(Wherein, R ₁ represents —C (CH ₃ ) ₂ —CH ₂ —R ₂ , R ₃ represents HM ₁ , and M ₂ represents Na).

[0037]

[Table 3]

As is clear from Table 3, when 1.5% of the cement solid content is added, the stabilizer to which only the anionic polymer is added is significantly contaminated, becoming a tofu-like gel and losing wall forming ability. The amount of dehydration is significantly increased.
The extent of gelation is much smaller than CMC.

Example 3 In the same manner as in Example 1, a bentonite suspension (3% (weight / volume)) was prepared. 600ml of this bentonite suspension
Into a container, the weight average molecular weight is 1.7 × 10 ⁴ (molecular weight in terms of polyethylene oxide), the number average molecular weight is 1.2 × 10 ⁴ (molecular weight in terms of polyethylene oxide), the pH is 4.9 (1% by weight aqueous solution), and the viscosity is 3.4 cps ( 1% by weight aqueous solution, B-type viscometer, 60 rpm, 25 ° C.). In all structural units, Y ₁ represented by the following formula is 21% by weight, Y ₂ is 46% by weight, and Y ₃ is 33% by weight.
1.8 g of zwitterionic polymer (B) contained in
3% (weight / volume)) and stirred at 5000 rpm for 10 minutes to prepare a stable liquid. To this stable solution, 27.3 g / 600 ml of cement slurry (1.5% cement solid content) prepared in the same manner as in Example 1 was added, stirred at 5,000 rpm for 10 minutes, and allowed to stand for 24 hours. After standing for 24 hours, the state of the stable solution was visually observed, and the mixture was again stirred at 5,000 rpm for 5 minutes, and FV, AV, P
V, YV, Gel, FL, and MC were measured. Table 4 shows the results.

[0040]

Embedded image

[0041] (wherein, R _4, R ₅ is CH ₃ R ₆ is -CH ₂ CH = CH ₂ A ^- is Cl ^- M ₃ represents respectively Na.)

[0042]

[Table 4]

As is evident from Table 4, the stable solution to which only the zwitterionic polymer was added did not gel even if the cemet solid content was 1.5%. However, the wall-forming properties are rather small, and are not suitable for practical use.

Example 4 Cell Base Mud RB-35, RB- manufactured by Daicel Chemical Industries, Ltd.
The above-mentioned CMC (symbol A) having the same degree of substitution as 35 and the above-mentioned CMC (symbol D) with a degree of substitution of 2.02, and a degree of substitution of 0.
The weight ratio of each of the four CMCs of 99 CMCs (symbol E) and the same zwitterionic polymer used in Example 3
1.8 g (0.3% (weight / volume)) was added to 600 ml of a 3% suspension of bentonite prepared in the same manner as in Example 1 and mixed at 60/40 in advance.
By stirring at pm, a polymer stable liquid was prepared. 27.3 g / 600 ml of cement slurry prepared in the same manner as in Example 1 for each 600 ml of the polymer stabilizing solution (cement solid content)
1.5%), stirred at 5,000 rpm for 5 minutes, and allowed to stand for 24 hours. After standing for 24 hours, the state was visually observed and stirred in the same manner as in Example 1 to obtain FV, AV, PV, YV, Gel, FL,
The MC was measured. Table 5 shows the results.

[0045]

[Table 5]

As is clear from Table 5, by using the zwitterionic polymer and CMC together, the polymer stabilizing solution using any of the CMCs did not gelate even if the cement solid content was 1.5%, and did not cause dehydration. The amount is small and the mud wall becomes thin. Among them, the stabilizer using the CMC having a substitution degree of 0.99 (symbol E) has a lower state after 24 hours of standing, the amount of dehydration, and the mud wall compared to the stabilizer using the CMC having a substitution degree of 1.2 to 1.5. Although inferior, cement resistance is remarkably improved without causing gelation. CMC having a degree of substitution of 2.02 (symbol D) has a feature of providing a particularly thin and strong mud wall when used in combination with a zwitterionic polymer.

Example 5 The same anionic polymer used in Example 2 and the same zwitterionic polymer used in Example 3 were mixed at a weight ratio of 50/50.
1.8 g (0.3%) per 600 ml of 3% bentonite suspension prepared in the same manner as in Example 1
(Weight / volume)), and stirred at 5000 rpm for 10 minutes to prepare a polymer stable liquid. 600 ml of this polymer stabilizer
Then, 27.3 g / 600 ml (cement solid content: 1.5%) of a cement slurry prepared in the same manner as in Example 1 was added, and the mixture was stirred at 5,000 rpm for 5 minutes, and then allowed to stand for 24 hours. After standing for 24 hours,
The state was visually observed and stirred in the same manner as in Example 1 to obtain FV,
AV, PV, YV, Gel, FL, and MC were measured. Table 6 shows the results.

[0048]

[Table 6]

As is apparent from Table 6, when the amphoteric ionic polymer (B) and the anionic polymer (A) were used in combination, even if the cement solid content was 1.5%, gelling did not occur and the wall-forming property was also improved. It becomes better, the amount of dewatering becomes smaller, and the mud wall becomes thinner.

Example 6 Next, Cell Base Mud RB-35 manufactured by Daicel Chemical Industries, Ltd.
And a weight average molecular weight of 3.9 × 10 ⁴ (molecular weight in terms of polyethylene oxide), a number average molecular weight of 1.9 × 10 ⁴ (molecular weight in terms of polyethylene oxide), a pH of 7.0 (1% by weight aqueous solution),
Viscosity of 5.3 cps (1% by weight aqueous solution, B-type viscometer, 60 rpm, 2
The difference in cement resistance due to the difference in the proportion of the zwitterionic polymer used in Example 3 except that the temperature was 5 ° C is shown. That is, RB-35 and a zwitterionic polymer were used in a weight ratio of 70/30 and 60/4, respectively, to a bentonite suspension (3% (weight / volume)) prepared in the same manner as in Example 1.
0.3% and 0.2% of the concomitant materials mixed at the ratios of 0, 50/50, 40/60 and 30/70 were added to prepare a polymer stabilizing solution. Cement slurries prepared in the same manner as in Example 1 were added to the polymer stabilizing solution at 27.3 g / 600 ml (solid content: 1.5%), and the cement resistance was evaluated in the same manner as in Example 1. Table 7 shows the results.

[0051]

[Table 7]

As is clear from Table 7, the amount of the concomitant substance was
The 0.3% polymer stabilizer has excellent wall-forming properties at any combination ratio shown in Table 7, and the cement solid content is
Even when 1.5% is mixed, the amount of dehydration is small and the mud wall is thin and durable. In addition, it is very stable without gelling even after standing for 24 hours. Further, the combined use of the combined use ratio of 60/40 to 40/60 has a good wall-forming property, a small amount of dehydration, a thin mud wall, and good even when the addition amount is 0.2%, and also after standing for 24 hours. Very stable. However, compared to these combined ratios, the combined amounts of the combined ratios of 70/30 and 30/70 have an addition amount of 0.
In the case of 2%, if the cement solid content is 1.5%, the state after standing for 24 hours becomes slightly unstable, and both the dewatering amount and the mud wall deteriorate. Therefore, the combined ratio of CMC and zwitterionic polymer is preferably 60/40 to 40/60.

Example 7 The same anionic polymer used in Example 2, having a weight average molecular weight of 3.9 × 10 ⁴ (molecular weight in terms of polyethylene oxide), a number average molecular weight of 1.9 × 10 ⁴ (molecular weight in terms of polyethylene oxide) and a pH of 7.0 (1% by weight aqueous solution), viscosity
5.3 cps (1% by weight aqueous solution, B-type viscometer, 60 rpm, 25 ° C)
The difference in cement resistance due to the difference in the combination ratio with the same zwitterionic polymer used in Example 3 except that That is, a polymer and a zwitterionic polymer were added to a bentonite suspension (3% (weight / volume)) prepared in the same manner as in Example 1 by weight ratio of 70/30, 60/40, 50, respectively.
0.3% and 0.2% of the combined materials mixed at the ratios of / 50, 40/60 and 30/70, respectively, were added to prepare a polymer stabilizer.
Cement slurries prepared in the same manner as in Example 1 were added to the polymer stable solution at 27.3 g / 600 ml (cement solid content: 1.5%), respectively, and the cement resistance was evaluated in the same manner as in Example 1. Table 8 shows the results.

[0054]

[Table 8]

As is clear from Table 8, the amount of the concomitant substance was
In the case of 0.3%, when the combined ratio of the anionic polymer (A) and the amphoteric polymer (B) is 70/30 to 30/70, even if the cement solid content is 1.5%, the wall formation does not occur even if the cement content is 1.5%. It has excellent properties, low dewatering amount, and the mud wall is thin and durable. When the combined amount of additive is 0.2%, the combined ratio is 60/40 to 4
In the case of 0/60, the wall formation property is good, the amount of dehydration is small,
Mud walls are thin and durable.

Example 8 The difference in cement resistance between the cell base mud RB-35 manufactured by Daicel Chemical Industries, Ltd., the same anionic polymer used in Example 2 and the same zwitterionic polymer used in Example 3 was measured. Show. That is, for a bentonite suspension (3% (weight / volume)) prepared in the same manner as in Example 1,
0.3% of a combined use of RB-35, anionic polymer and amphoteric polymer mixed at a weight ratio of 50/10/40 was added to prepare a polymer stabilizer. A cement slurry prepared in the same manner as in Example 1 was used for the polymer stabilizing solution.
Example 1 with addition of 27.3g / 600ml (cement solid content 1.5%)
Cement resistance was evaluated in the same manner as described above. Table 9 shows the results.

[0057]

[Table 9]

Claims (6)

[Claims] (1) Na-carboxymethylcellulose or /
And an anionic polymer (A) shown below, and
Contains a zwitterionic polymer (B) as an essential component
An additive for a stable liquid method. Anionic polymer (A): Formula X below₁, X_Two, X_Threeso
The three types of repeating structural units represented by X in all structural units₁
Is 0.5 to 15% by weight, X_TwoIs 13 to 50% by weight, X_ThreeIs 40-85
A polymer contained in the proportion of% by mass. Embedded image(Where R₁Is -C (CH_Three)_TwoCH_Two-Or any organic functional group
Express. R_Two, R_ThreeIs a hydrogen atom or -CH_TwoCH_Two-OH
A few, or both, represent any organic functional groups. M₁,
M_TwoRepresents a hydrogen atom, sodium or potassium. ) Zwitterionic polymer (B): Formula Y below₁, Y_Two, Y_Threeso
The three types of repeating structural units represented by₁
Is 5 to 40% by weight, Y_TwoIs 20-65% by weight, Y_ThreeBut 10-50 weight
% Polymer. Embedded image(Where R_Four~ R₆Is a hydrogen atom, an alkyl group or an alkenyl
Group, A^-Is Cl^-Or Br^- Represents M_ThreeIs sodium, mosquito
Represents lium, calcium or magnesium. ) 2. The additive for a stable liquid method according to claim 1, wherein the anionic polymer (A) is a substance that simultaneously satisfies the following characteristic values. 1% by weight aqueous solution viscosity: 50 to 550 cps (B-type viscometer, 25 ° C.) Weight average molecular weight: 1 × 10 ^{6 to} 3 × 10 ⁶ (polyethylene oxide equivalent molecular weight) Number average molecular weight: 2 × 10 ^{5 to} 6 × 10 ⁵ (Molecular weight in terms of polyethylene oxide) 3. The additive for a stable liquid method according to claim 1, wherein the zwitterionic polymer (B) is a substance that simultaneously satisfies the following characteristic values. 1% by weight aqueous solution viscosity: 2 to 20 cps (B-type viscometer, 25 ° C.) Weight average molecular weight: 1 × 10 ^{4 to} 5 × 10 ⁴ (polyethylene oxide reduced molecular weight) Number average molecular weight: 0.5 × 10 ^{4 to} 3 × 10 ⁴ (Molecular weight in terms of polyethylene oxide) 4. Na-carboxymethylcellulose or /
The weight ratio between the anionic polymer (A) and the amphoteric ionic polymer (B) is 30/70 to 70/30, for the stable liquid method according to any one of claims 1 to 3. Additive. 5. An excavating stabilizing liquid, comprising using the additive for stabilizing liquid method according to claim 1. Description: 6. A civil engineering excavation method using the excavation stabilizing liquid according to claim 5.