JPS6136877B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a mud water composition suitable for mud drilling methods that has a stable viscosity over a long period of time. Add carboxymethylulose, guar gum, sodium alginate, etc. to the aqueous suspension of clay, bentonite, etc.
Using muddy water containing colloidal polysaccharides such as α-starch, the ground can be excavated while preventing the collapse of trench (hole) walls, and the face can be stabilized with muddy water and excavated to construct tunnels. The so-called mud drilling method is widely used as a pollution-free construction method. The muddy water used in this muddy drilling method has the function of stabilizing trench (hole) walls and faces by forming an impermeable mud cake (mud cake) through the interaction of clay and bentonite in the muddy water with colloidal polysaccharides. It is something that you have. However, muddy water containing colloidal polysaccharides is susceptible to deterioration due to the contamination of bacteria present in soil during muddy preparation or drilling use, and as a result, the viscosity of the muddy water and its ability to form an impermeable mud film are reduced. , groove (hole)
The stabilizing function of walls and faces deteriorates, which tends to cause deterioration such as the generation of bad odors and poor dispersion, which also affects the safety of construction work. Using altered mud water for excavation has a high risk of collapsing, so it has traditionally been disposed of, resulting in large economic losses, and as a preventative measure, anti-alteration agents have been added to the mud. Salicylic acid, sorbic acid, paraoxybenzoic acid ester, organic sulfur, or organic nitrogen-based agents are known as anti-alteration agents, but these agents are used to prevent groundwater contamination due to lost sludge during excavation or after use. Considering the removal treatment of the deterioration prevention agent from the waste mud water, it is impossible to mix a large amount into the mud water. In addition, anti-deterioration agents with high antiseptic or bactericidal effects are highly toxic, and those with low toxicity are less effective, so the reality is that there are no anti-deterioration agents that are satisfactory in terms of cost and effectiveness. be. The purpose of the present invention is to develop a muddy water excavation method that can maintain the properties of muddy water stably for a long period of time without using any deterioration prevention agents that may affect the human body or other living things. An object of the present invention is to provide a suitable mud water composition. The composition of the present invention has an inherent viscosity (hereinafter referred to as [η]) in 2N caustic soda of muddy water containing at least one type of inorganic clay.
It is characterized in that it is made by mixing an acrylic acid resin having an amount of 0.01/g or less and an acrylic acid resin having the above [η] of 0.08 to 0.8/g. The acrylic acid resin used in the present invention may be a homopolymer or a copolymer of acrylic acid monomers. As the homopolymer, it is preferable to use alkali metal salts of polyacrylic acid, and as the copolymer, one or more of acrylic acid and other acrylic monomers, such as acrylonitrile, methyl acrylate, ethyl acrylate, etc. Preferably, it consists of In the latter case, the main component is especially acrylic acid. It is effective to use a coweight containing 10 to 50 parts by weight of other acrylic monomers per 100 parts by weight of acrylic acid. This kind of acrylic acid resin is suitable for water in muddy water.
0.01 to 5 parts by weight of acrylic acid resin with [η] of 0.01/g or less, [η] of 0.08 to 100 parts by weight
It is preferable that 0.8/g of acrylic acid resin be mixed into the muddy water at a ratio of about 0.01 to 5 parts by weight. In any case, if the amount added is less than 0.01 part by weight, the effect is lacking, and if it is added in an amount of 5 parts by weight or more, it is uneconomical. usually,
[η] Acrylic acid resin of 0.01/g or less 0.05~
It is more effective to add about 0.03 to 2 parts by weight of acrylic acid resin, [η] 0.08 to 0.8/g. [η] 0.01/g or less acrylic acid resin mainly works as a dispersant, [η] 0.08 to 0.8/g
The acrylic acid resin acts as a thickener and a dehydration amount regulator. In addition, resins with [η] larger than 0.01/g lack dispersion effect, resins with [η] smaller than 0.08/g have poor thickening effect, and resins larger than 0.8/g have disadvantages such as too strong cohesiveness. has. The present invention improves all of the thickening properties, wall-building properties, and dispersibility of muddy water compositions by using two types of acrylic acid resins with different properties in combination,
In particular, a very stable composition can be obtained without using a deterioration inhibitor. The acrylic acid resins may be added to the muddy water at the same time, but it is preferable to add the resin with an [η] of 0.01/g or less first, and then add the resin with an [η] of 0.08 to 0.8/g. Particularly when the specific gravity of muddy water is high, if a resin with a high [η] is added first, agglomeration may occur, making stirring difficult. The muddy water in the present invention contains one or more types of inorganic clay such as montmorillonite, attapulgite, sericite, kaolinite, etc.
Its content varies depending on the purpose of use. Generally, inorganic clay is 0.5 to 100 parts by weight of water.
Contained in the range of 100 parts by weight, for example, underground continuous walls,
The amount of mud used in cast-in-place pile construction methods (so-called stabilizing liquid) is approximately 0.5 to 10 parts by weight, that used in mud shield construction methods is approximately 10 to 50 parts by weight, and the slurry used in mud shield construction methods is approximately 50 parts by weight. It is said that about 100 parts by weight of inorganic wet clay should be included. In either case, the composition of the present invention can be effectively applied. Note that the muddy water composition of the present invention further contains commercially available mountain clay, excavated silt clay, various polyphosphates,
Dispersants such as lignin sulfonate and nitrofumate, PH regulators such as soda ash, anti-sludge agents such as cotton seed residue, and additives such as water-soluble polymer compounds such as carboxymethyl cellulose and starch derivatives. may be included. Next, the effects of the present invention will be explained in more detail using examples. Note that all parts described below indicate parts by weight. Example [1] To 90 parts of well water, add 10 parts of altered mud water, 3 parts of bentonite (produced in Yamagata Prefecture), and 1 part each of the following thickeners.
Five kinds of mud water compositions were prepared by adding and mixing seeds. Thickener A Sodium polyacrylate ([η] = 0.004/
g) Combination of 0.5 part of sodium acrylate and 0.05 part of methyl acrylate copolymer ([η] = 0.8/g) B: 0.3 part of sodium acrylate acrylonitrile copolymer ([η] = 0.01/g) and polyacrylic acid Combined use of 0.5 parts of soda ([η] = 0.02/g) C Potassium polyacrylate ([μ] = 0.008/
g) 0.3 parts and methyl acrylate copolymer ([η]
= 0.6/g) 0.1 part D Carboxymethyl cellulose (1% anhydride aqueous solution 25℃ viscosity 100 cp) 0.3 parts E Guar gum (1% anhydride aqueous solution 25℃ viscosity
620 cp) 0.2 parts This muddy water composition was stored in a thermostatic chamber at 30°C, and changes in viscosity over time were measured. The results are shown in Table 1. The altered mud water used was muddy water with a reduced viscosity and a foul odor collected from a waste mud treatment plant. In addition, for the viscosity test, 500 ml of the muddy water composition adjusted to 25° C. was placed in a 500 ml Marseille Funnel clay meter, and the outflow time of 500 ml was measured. The amount added varies depending on the type of thickener, but this is because the viscosity of the muddy water composition immediately after adjustment was adjusted to about 30 seconds, the same as that of normally used muddy water. (The viscosity of fresh water is 18.5±0.5 seconds.)

[Table] Samples No. 1 to 3, which are compositions according to the present invention
It can be seen that this sample has a much more stable viscosity than Sample Nos. 4 and 5, which used a general thickener. Example [2] To 90 parts of well water, 10 parts of altered mud water, 30 parts of commercially available clay (produced in Gifu Prefecture), and one type of each of the following thickeners were added and mixed to obtain five types of mud water compositions. Thickener F Sodium polyacrylate ([η] = 0.008/
g) Combination of 0.3 part and 0.5 part of sodium acrylate acrylonitrile copolymer ([η] = 0.08/g) G Potassium polyacrylate ([η] = 0.004/
g) Combined use of 0.5 part and 0.04 part of sodium acrylate methyl acrylate copolymer ([η] = 0.8/g) H Sodium polyacrylate ([η] = 0.01/g)
Combination of 0.5 parts and 0.08 parts of sodium acrylate and acrylonitrile copolymer ([η] = 0.6/g) I Carboxymethyl cellulose (1% anhydride aqueous solution, viscosity at 25°C, 1000 cp) 0.2 parts J Guar gum (1% anhydride aqueous solution, viscosity at 25°C)
300 cp) 0.5 part The viscosity change of this muddy water composition was measured under the same conditions as in Example [1]. The results are shown in Table 2. The same modified mud water as in Example [1] was used, and the amount of thickener added was the same as in Example [1].
It was selected so that the viscosity immediately after adjustment would be around 30 seconds.

[Table] Sample No. 6 ~ which is a muddy water composition according to the present invention
It can be seen that Sample No. 8 is a very stable product compared to Sample Nos. 9 and 10, which used a general thickener. Example [3] Sodium polyacrylates having different intrinsic viscosities as shown in Table 3 were dissolved in a suspension prepared by adding 3 parts of bentonite to 100 parts of water to obtain six types of muddy water compositions. 10 parts of Kanto loam was added to 100 parts of this muddy water composition, and the mixture was left to stand for one day, and its dispersion stability was observed. The results are shown in Table 3. Samples Nos. 11 to 13, in which two types of sodium polyacrylate were used together according to the present invention, did not aggregate even when Kanto loam was mixed, and the dispersion stability was good.
Samples No. 14 to 16 using seed polyacrylic acid soda
However, good dispersibility could not be obtained. In addition, in sample No. 14 using sodium polyacrylate with a low intrinsic viscosity [η] = 0.01/g, no thickening effect of the muddy water composition was observed even when the amount added was increased to 5 parts.

【table】

Claims (1)

[Scope of Claims] 1. Mud water containing at least one kind of inorganic clay has an intrinsic viscosity of 2N in caustic soda.
A mud water excavation method having a long-term stable viscosity characterized by mixing a low viscosity acrylic acid resin having an intrinsic viscosity of 0.01/g or less and a high viscosity acrylic acid resin having an intrinsic viscosity of 0.08 to 0.8/g. Muddy water composition suitable for. 2. A patent claim characterized in that 0.01 to 5 parts by weight of the low viscosity acrylic acid resin and 0.01 to 5 parts by weight of the high viscosity acrylic acid resin are mixed with 100 parts by weight of water in the muddy water. A muddy water composition according to Scope 1. 3. The muddy water composition according to claim 1 or 2, wherein the muddy water contains inorganic clay in a ratio of 0.05 to 100 parts by weight per 100 parts by weight of water. 4. A patent characterized in that each of the acrylic acid-based resins is selected from the group consisting of an alkali metal salt of polyacrylic acid and a copolymer consisting of 100 parts by weight of acrylic acid and 10 to 50 parts by weight of other acrylic acid monomers. A muddy water composition according to any one of claims 1 to 3.