JPS6252786B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lubricant composition for shield propulsion construction. More specifically, after shield propulsion, an aqueous suspension consisting of an aqueous dispersion of superabsorbent hydrogel, minerals, organic thickeners, surfactants, and oils is mixed into the tube and the pores. The present invention provides a lubricant composition for shield propulsion construction, which is injected between walls to reduce propulsion resistance and also functions as a backfill material. Since the shield propulsion method does not involve excavation of the ground, it poses little hindrance to traffic and commercial activities, and is a low-pollution construction method that causes less ground movement, vibration, and noise, making it ideal for conduits for water, sewage, gas, telegraph and telephone lines, power lines, etc. This method is often used for laying cables. In the shield propulsion method, the contact area between the propulsion tube and the hole wall increases according to the propulsion distance, so the resistance also increases in proportion to the propulsion distance, and as the propulsion distance increases, propulsion accuracy and work efficiency decrease and the tube body Because of this, it is common practice to inject friction reducers or lubricants. Bentonite is traditionally added to water as a friction reducer.
A viscous suspension containing an organic paste, a surfactant, and a mineral oil is often injected between the tube and the hole wall to reduce frictional resistance during propulsion. However, since this viscous suspension is in the form of a soft gel, even if it is injected between the tube and the hole wall, it cannot withstand the weight of the tube, and the tube gradually sinks, causing direct contact between the bottom of the tube and the ground. condition, and a significant reduction in propulsion resistance cannot be expected.
Propulsion is carried out by installing a plurality of intermediate push devices (hydraulic jacks) in the middle of the tube. By significantly increasing the viscosity of this viscous suspension, it is possible to prevent the tube from sinking to some extent, but on the other hand, it becomes extremely difficult to inject the liquid, and the filling rate also decreases, making it difficult to propel the tube. The effect of further lowering the resistance cannot be expected. Furthermore, when the propulsion ground is a water-retaining layer or flowing water layer, the viscous suspension is often diluted by water or washed away from the injection point, significantly reducing its effectiveness. As a countermeasure to this problem, a method has been proposed in which cement or gypsum is added to the viscous suspension to give it hardness and then injected in a gel state, but in the end it becomes difficult to inject due to a decrease in fluidity, and the filling rate is also low. A sufficient friction-reducing effect is not achieved, and furthermore, there is a risk of ground subsidence due to insufficient filling. A backfilling effect is achieved by completely filling the space between the pipe body and the hole wall with the viscous suspension, but as time passes, it permeates into the ground or is washed away, and this effect is lost. The pipe body is fixed by press-fitting pea gravel concrete, mortar cement, soil cement, etc. as a backfilling material into the gap between the pipe and the hole wall to prevent ground subsidence. In this method, a friction reducing agent is injected and pushed, and then the backfill material is pressed in, so the work process is two stages. This tends to cause ground surface subsidence due to hole wall collapse. Also, in Japanese Patent Application Laid-open No. 52-75032,
Methods have been proposed to reduce frictional resistance when pushing the propulsion tube and provide a backfilling function by injecting a water glass grout or a sand mortar grout, but propulsion tubes are usually made of concrete or cast iron and the grouting agent is injected into the propulsion tube. They tend to stick to these propulsion pipes and require extremely skilled construction techniques. The present inventor has improved these conventional techniques and has already developed a shield propulsion method in which a mineral substance, a carboxyl group-containing water-soluble polymer compound, a basic lower carboxylic acid aluminum salt, a surfactant, and/or mineral oil are mixed in water. Backfilling material composition characterized by being injected between the pipe body and the hole wall to reduce propulsion resistance
No. 1), which reduces propulsion resistance and backfills in a single process, improving propulsion efficiency and preventing hole wall collapse and ground subsidence. However, a relatively large amount of chemicals is required to increase the gel strength of this backfill material composition, resulting in high construction costs. Furthermore, the present inventor has conducted intensive research to overcome the deficiencies of the prior art, and as a result, has been able to provide an excellent lubricant composition. That is, an aqueous dispersion of superabsorbent hydrogel or an aqueous suspension containing minerals, organic pastes, surfactants, and oils as necessary is injected between the tube body and the hole wall after shield propulsion. An object of the present invention is to provide an anti-friction agent composition for shield propulsion construction, which is characterized by reducing propulsion resistance and also having the function of a backfilling material. The lubricant composition of the present invention has high fluidity during injection and can obtain a high filling rate. After filling, the superabsorbent hydrogel highly absorbs water and swells, exhibiting high gel strength, so the propulsion tube can be immobilized, and the pore walls do not collapse, preventing ground subsidence. In particular, when injected into ground with stagnant or flowing water, conventional lubricant compositions lose their effectiveness due to water dilution or washing away, whereas in the composition of the present invention, the superabsorbent hydrogel absorbs water and swells, reducing the hydraulic conductivity. Since it exhibits a blocking effect even on ground with high water flow, it is particularly effective on ground with stagnant water or flowing water without water dilution or runoff. Furthermore, a highly water-reducing effect can be obtained over a long period of time in synergy with the highly water-absorbent hydrogel or organic thickeners, surfactants, and oils that are added as necessary. The superabsorbent hydrogel used in the present invention refers to a hydrogel that absorbs water and swells several to hundreds of times, but does not dissolve in water, such as a starch-acrylonitrile or starch-methacrylate graft copolymer part. Hydrolysates (see U.S. Pat. No. 3,425,971), partial hydrolysates of polyacrylonitrile and vinyl ester-ethylenically unsaturated carboxylic acid copolymers, olefinic polymers with hydrophilic groups introduced such as sulfonated styrene, polyethylene oxide , polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, sodium polyacrylate-polyacrylamide copolymer, carboxymethylcellulose, pullulan, etc., irradiated products of water-soluble polymer compounds (Japanese Patent Publication No. 1982-27039) and methylene bis. Crosslinked products using crosslinking agents such as acrylamide, dichloroacetic acid, epichlorohydrin, aldehydes, etc.
17965, JP-A-50-80376, etc.), and even those in which part of the hydrophilic group is replaced with a lipophilic group (JP-A-1987-80376, etc.).
No. 22029) (heat-treated modified product), etc., can be used to highly absorb water and exhibit high swelling when dispersed in water. This highly water-absorbent hydrogel absorbs water and swells several to hundreds of times, so a particle size of about 30 to 300 mesh is suitable. The swelling ratio, swelling rate, and gel strength after swelling of the superabsorbent hydrogel added as an anti-friction agent composition are determined depending on the degree of polymerization of the polymer, the type of crosslinking agent, the degree of crosslinking, the hydrolysis rate, the particle size, etc. It is possible to select. After this superabsorbent hydrogel is injected between the tube and the hole wall as an anti-friction agent composition, it highly absorbs water and swells over time to form a gel state, stabilizing the hole wall and improving the tube body. Furthermore, by existing as a gel body between the tube body and the hole wall, it prevents direct contact between the tube body and the hole wall, preventing an increase in contact resistance, and at the same time, the gel body The anti-friction effect can greatly reduce propulsion resistance. In addition, even if hydrogel added as fine particles absorbs water and swells, it becomes relatively large particles, so even if it is injected into ground with standing or flowing water, it is possible to prevent the movement of groundwater by acting as a sealant, and water dilution is possible. It has the characteristic of preventing a decline in effectiveness due to water loss or washing away over a long period of time. In the present invention, mineral substances that are blended into the superabsorbent hydrogel dispersion as necessary include those having self-lubricating properties such as clay, bentonite, and graphite, and sand, fly ash, and the like may also be used as fillers. Can be done. These mineral substances are generally inexpensive, and the amount of superabsorbent hydrogel incorporated into the lubricant composition can be reduced, thereby reducing the cost of the lubricant composition. In addition, organic thickeners include carboxymethyl cellulose soda salt, sodium alginate, sodium polyacrylate, polyvinyl alcohol, guar gum,
Starch and its derivatives, etc. can be used. By blending these organic thickeners into a lubricant composition, the effects of imparting viscosity to the composition and preventing syneresis can be obtained. Surfactants include soap, alkyl sulfate,
Alkyl phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl ether sulfates, polyalkylene glycols,
Examples include polyethylene glycol-polypropylene glycol block polymers, sulfurized fatty acids, sulfurized fatty oils, chlorinated fatty acid salts, polyoxyethylene alkyl ether phosphates, petroleum sulfonates, etc. used as extreme pressure additives. These surfactants are effective as lubricating agents under reduced pressure, and also act as emulsifying and dispersing agents for oils added as lubricating components. Mineral oils and vegetable oils that are liquid at room temperature can be used as the oils added as lubricating components, and liquid fatty acids and liquid higher alcohols can also be used for the same purpose. Examples of the mineral oil include kerosene, light oil, heavy oil, spindle oil, and machine oil. However, in consideration of odor, fire risk, and lubricating effect, mineral oil equivalent to lubricating oil such as spindle oil or machine oil is preferable. Vegetable oils include rapeseed oil, castor oil, soybean oil, etc. Liquid fatty acids include oleic acid, linoleic acid, ricinoleic acid, isostearic acid, etc. Liquid higher alcohols include natural lanolin alcohol with 6 to 18 carbon atoms, oxo synthetic alcohol, etc. can be used. In addition to the above-mentioned effects, the organic thickener and surfactant added as necessary are also effective as regulators of the water absorption and swelling rate of the superabsorbent hydrogel. The anti-friction agent composition of the present invention can exhibit sufficient anti-friction action and effect as a backfilling material using only the aqueous superabsorbent hydrogel dispersion. Furthermore, by blending minerals, organic pastes, surfactants, and oils according to the conditions of the propulsion ground, it is possible to obtain a high degree of friction reduction effect, and also adjust the water absorption and swelling rate of the superabsorbent hydrogel. Therefore, it is also possible to adjust the gelation time of the lubricant composition depending on the soil. The practical blending ratio of the lubricant composition of the present invention is as follows. Water 100 (parts by weight) Super absorbent hydrogel 0.05-10 Minerals 0-50 Organic thickeners 0-5 Surfactants 0-5 Oils 0-10 Examples of the present invention are shown below. The present invention is not limited to this embodiment. (All parts and % in the examples indicate parts by weight and % by weight.) Example 1 Suspension of a predetermined amount of super absorbent hydrogel dispersed in 100 parts of water, mineral substances, organic thickening agent, and surfactant Add the mixed oil and add it to a 100ml beaker.
Take 100ml and check the change in consistency over time with RHEO
Measured using METER (NRM-2010 manufactured by J-type Fudo Kogyo Co., Ltd.). Measurements are made at 20°C with a diameter of 30
A disk (7.06 cm ² ) of m/m was moved up and down continuously at a speed of 50 m/m/min, and the load applied to the disk at that time was read from a recorder and used as the gel strength. In addition, standard sand (manufactured by Toyoura Silica Industry Co., Ltd.) was well moistened with water and tamped, and after 24 hours, the composition prepared above was applied to a thickness of 10 m/m.
Concrete block (width 65m/m, height 60m)
A rectangular shape with a length of 160 m/m and a weight of 1500 g was placed on it, and immediately pulled using a spring scale to measure the maximum static friction at that time. The measured results are shown in Table 1.

[Table] Example 2 Using various super absorbent hydrogels, gel strength and maximum static friction force were measured according to Example 1, and the results are shown in Table 2.

【table】

[Table] Example 3 100 ml of an anti-friction composition obtained by adding and mixing a superabsorbent hydrogel dispersion in water, mineral substances, organic thickeners, surfactants, and oils was added to an 80-mesh stainless steel mesh. It was placed in a wire mesh basket and suspended in a glass beaker containing 100 ml of water, and the condition was observed after one day. The results are shown in Table 3.

[Table] Example 4 Diameter 1650m/m, length by mud propulsion method
In the installation of a 2.43 m concrete propulsion pipe into a 6.5 m water-retaining sand layer, 100 parts of water and a polyacrylic acid soda methylene bis acrylamide cross-linked product (80 mesh pass product) were used as the lubricant composition of the present invention.
By injecting a mixed dispersion of 0.1 part of bentonite (Kunigel V) and 6 parts of bentonite (Kunigel V) between the propulsion tube and the hole wall,
As shown in Figure 1, the thrust decreased. In other words, as shown in Figure 1, when 20 propulsion pipes were installed, the actual thrust was 250 tons, compared to the planned thrust of 420 tons, resulting in a thrust reduction effect of 47%. In addition, 30 years after the propulsion pipe was installed
No ground surface subsidence was observed even after several days had passed.

[Brief explanation of the drawing]

FIG. 1 is a graph showing how the thrust force decreases when the composition of the present invention is used in Example 4.

Claims (1)

[Claims] 1 An aqueous dispersion of a highly water-absorbent hydrogel, mixed with minerals, organic thickeners, surfactants, and oils as necessary, is injected between the tube body and the hole wall after shield propulsion. In addition to reducing propulsion resistance,
An anti-friction agent composition for shield propulsion construction method, which is characterized by having the function of a backfilling material.