JPH0759701B2 - Ground remodeling filler - Google Patents

Description

The present invention relates to a ground remodeling filler.

More specifically, the present invention relates to a ground remodeling filler suitable as a filler used when remodeling / stabilizing the ground by a high-pressure injection total replacement method.

[Prior art]

There is a high-pressure injection method as one of the construction methods for stabilizing the ground by using a soil stabilizer to strengthen the soft ground and stop water leakage. In this method, high-pressure water is sprayed into the ground, the jet energy is used to cut the inside of the ground, and the resulting cavity is filled with a soil stabilizer and hardened to harden the ground layer in the ground. There is a so-called high-pressure jet total replacement method in which the body is replaced. (SSS-MAN method, etc.). Conventionally, in this construction method, a cement-based soil stabilizer composed of cement, aggregate and water is usually used as a filler.

[Problems to be solved by the invention]

However, the conventional filler composed of cement, aggregate and water has the following problems.

1) Immediately after mixing cement, aggregate and water by mixing and mixing, there is fluidity, but over time, a solid-liquid separation (breathing) phenomenon occurs, resulting in non-uniformity and loss of fluidity.

When such a filling material that is easy to breathe is filled in the cavity obtained by cutting the inside of the ground, a layer of water generated by the breathing of the filling material occurs at the boundary between the ground and the filling point, and there is a part that is not improved. Since it remains, it causes ground subsidence.

2) In addition, the filler that causes the breathing phenomenon in a short time loses its fluidity in a short time, so it is difficult to reach the entire area when the cutting cavity is wide, and the part that cannot be replaced remains and the ground is modified or stabilized. Becoming uncertain.

3) The strength of the cement-rich hardened body formed by the separation and sedimentation of cement by breathing is extremely high. Breathing tends to be suppressed by increasing the ratio of cement, but the strength of the hardened body obtained when the ratio of cement is increased to suppress breathing is extremely high, and it is suitable for excavation work after ground stabilization. It takes a long time and it becomes difficult to carry out excavation work in the shield work.

[Means for solving problems]

The present inventors have improved the above-mentioned problems, maintained fluidity for a long time, and have a small breathing rate, and when the ground is filled and hardened, excavation work and shield work performed after modification and stabilization of the ground In order to provide a ground remodeling filler capable of forming a hardened body having an appropriate strength without deteriorating the efficiency of the excavation work in the field, cement, aggregate, water reducing agent, water-soluble polymer and water were investigated. The present invention has been completed by finding that the above object can be achieved by using a composition obtained by mixing and kneading in an amount ratio within a specific range as a filler.

That is, the present invention, cement-aggregate-water-reducing agent-water-soluble polymer-in the composition for filling in the ground formed by blending water, water / cement-weight ratio is 2.2 or less, and the aggregate is A ground remodeling filler which does not have hydraulic properties and which is prepared by mixing the respective materials in an amount ratio within the following range.

(1) Cement: 160 to 400 parts by weight, (2) Aggregate: 1300 to 1500 parts by weight, (3) Water reducing agent: 0.5 to 15 parts by weight, (4) Water-soluble polymer: 1.5 to 8 parts by weight, (5) ) Water: 320 to 350 parts by weight. Is the main point.

(1) The cement used in the present invention includes ordinary Portland cement, (super) early strength Portland cement, moderate heat Portland cement, and low heat Portland cement.
Various portland cements such as sulfated portland cement, high iron oxide type portland cement, white portland cement, mixed cements such as blast furnace cement, silica cement, fly ash cement, masonry cement, expansive cement, alumina cement, ultra-rapid cement・ Special cements such as oil well cement, grout cement, sludge solidifying agent, toxic substance solidification treatment cement, high sulfate slag cement, etc.
These may be used alone or in combination of two or more.

Further, it is possible to use one obtained by replacing a part of these cements with hydraulic fly ash, silica fume, granulated blast furnace slag, type II anhydrous gypsum and the like.

Inexpensive and easily available ordinary portland cement, blast furnace cement, early strength portland cement, etc. are preferably used.

The particle size of the cement used in the present invention is preferably 100 μm or less. It may be used as it is as an ordinary commercial product.

Cement having a particle size of more than 100 μm causes breathing in a short time, which is not preferable. The particle size is 1 μm
Cement that is less than may be less prone to breathing, but is expensive.

In the present invention, the following additives are added to cement in order to achieve the above object.

(2) In the present invention, the aggregate incorporated into the cement has no hydraulic property, and so-called fine aggregate is used.
In addition, mud obtained by cutting the ground can also be used.

Examples of the aggregate used in the present invention include fine gravel, gravel, gravel soil, sand, sandy soil, and sandy silt that have passed through a 10 mm sieve, and fine aggregate for ready-mixed concrete that passes through a 50 mm sieve, for example, , Plaster sand, river sand, sea sand, mountain sand, silica sand, and crushed stone powder are preferably used. The particle size of the aggregate is preferably in the range of 0.15 to 2 mm.

Particles having a particle size of 10 mm or more are not unusable, but the composition obtained is easily breathable, the fluidity is lowered, and the strength of the cured product varies and is not preferable.

(3) In the present invention, a water reducing agent is used as another additive in order to improve the dispersibility of the cement and the aggregate with a small amount of water and to easily obtain the filler slurry.

The water reducing agent used in the present invention is usually used as an admixture for cement concrete, and specifically, for example, lignin sulfonate, polyalkylallyl sulfonic acid high condensate, oxycarboxylic acid, polyol complex,
Examples include β-naphthalene sulfonic acid high condensate, creosote oil sulfonic acid condensate, melamine formalin condensate sulfonate, and the like.

(4) In the present invention, a water-soluble polymer is further added in order to suppress bleeding of the filler composition and adjust the compressive strength of the resulting cured product.

Examples of the water-soluble polymer used in the present invention include poly (meth) acrylic acid or a salt thereof, synthetic polymer type such as polyacrylamide, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, and natural type such as methyl cellulose. It is possible to use one or more of these.

(5) Next, water is used as a fluidizing material for making the filler composition into a slurry.

The filler composition of the present invention can be obtained by blending the above materials in the following quantitative ratios.

(1) Cement: 160 to 400 parts by weight, (2) Aggregate: 1300 to 1500 parts by weight, (3) Water reducing agent: 0.5 to 15 parts by weight, (4) Water-soluble polymer: 1.5 to 8 parts by weight, (5) ) Water: 320 to 350 parts by weight. By mixing and kneading the above-mentioned materials each having a weight unit of “kg”, about 1 m ³ of the filler in slurry form can be obtained.

As an embodiment for producing the filler composition of the present invention, an appropriate device capable of mixing, stirring, and kneading powders or slurries is used, and cement, aggregate, water-reducing agent, water-soluble polymer at a predetermined ratio are used. And water are mixed and stirred and kneaded.

Further, as another aspect, the cement and the aggregate are pre-blended in a predetermined ratio of the present invention, other additives and water may be added in a predetermined ratio and kneaded, and each material is blended. The order of is not limited.

The kneading time after mixing all the materials is usually about 1 to 3 minutes, and at most 10 minutes or less.

The use amount ratio of cement in the filler composition of the present invention is 16
0-400, preferably 200-330, more preferably 220-280
The range is each part by weight.

The compressive strength of the hardened body to be constructed is 10 to 100 kgf so that the ground can be stabilized more reliably and safely, and the efficiency of excavation work at the stabilized location and excavation work in shield work will not be reduced. / cm ² , preferably 15-60 kgf /
cm ² , more preferably 20 to 50 kgf / cm ² .

If the amount ratio of cement used is less than 160 parts by weight, the compressive strength of the obtained cured product does not reach the safety requirement of 10 kgf / cm ² . On the other hand, if it exceeds 400 parts by weight, the compression strength of the obtained cured product will be 100 kgf / cm ² or more, and the efficiency of the excavation work in the excavation work or the shield work will be reduced, which is not preferable.

The ratio (total amount) of aggregate used is 1300 to 1500, preferably
The range is 1380 to 1470, and more preferably 1420 to 1460.

If the amount ratio of aggregate used is less than 1300 parts by weight, the relative ratio of cement becomes large, and the compression strength of the obtained hardened product is
If it exceeds 100 kgf / cm ^2, and the amount ratio of aggregate exceeds 1500 parts by weight, the relative ratio of cement decreases, and the resulting cured product has a compressive strength of less than 10 kgf / cm ² . None of them are preferable because they are not suitable for the purpose of the present invention.

Next, the addition ratio of the water reducing agent is 0.5 to 15, preferably 1 to 1.
0, and more preferably 2 to 6 parts by weight.

If the addition ratio of the water reducing agent is less than 0.5 parts by weight, it is difficult to make the composition into a slurry with a small amount of water, and the fluidity of the obtained composition is low.

On the other hand, if the addition amount ratio exceeds 15 parts by weight, the fluidity of the obtained composition does not improve so much, and the compression strength of the cured product decreases, which is not preferable.

The addition ratio of the water-soluble polymer is 1.5 to 8, preferably 2
6 to 6 parts by weight.

When the addition amount ratio of the water-soluble polymer is less than 1.5 parts by weight, the breathing rate of the obtained composition is large and the fluidity is low,
Furthermore, the compression strength of the obtained cured product varies, which is not preferable. On the other hand, if the addition amount ratio exceeds 8 parts by weight, the viscosity of the obtained composition will increase excessively and the fluidity will decrease, and if water is added to this to reduce the viscosity, the compression strength of the obtained cured product will decrease. It is not preferable because it is scattered and not stable, and it is not economical.

The viscosity of the filler composition of the present invention is 1000 to 20000 cps, preferably 2000 to 15000 cp, as measured by a B-type viscometer.
s, more preferably 3000 to 10000 cps.

If the viscosity of the composition is less than 1000 cps, the particle size is 100 μm
When the following aggregates are used, the breathing rate of the composition is small, but when the particle size of the aggregate is larger than this, the breathing rate increases, and thereby the fluidity of the composition decreases over time. However, the resulting cured product varies in compression strength.

When the viscosity of the composition exceeds 20000 cps, the breathing rate of the composition is small, and the compression strength of the obtained cured product is stable, but since the fluidity becomes small, the target cavity is uniformly filled during the ground modification construction. It is difficult to do so, and there is a possibility that the ground will be subsided due to uncertain stabilization of the ground due to the remaining unfilled parts.

The amount of water used in the filler composition of the present invention is 320 to 350.
The range is parts by weight.

In the filler composition of the present invention, the water / cement-weight ratio is 2.2 or less, preferably 2.2 to 0.8.

When the water usage ratio is less than 320 parts by weight, the breathing rate of the obtained composition is small, but the fluidity is low and the handleability is poor, and the strength of the obtained cured product is 100 kgf / cm ² . It is not preferable because it exceeds.

On the other hand, when the amount ratio of water used exceeds 350 parts by weight, the composition obtained has good initial fluidity, but the breathing rate becomes large. The composition after breathing has deteriorated fluidity,
The resulting cured product has a large variation in compressive strength, and
It is not preferable because it does not reach 10 kgf / cm ² .

As one aspect of the construction method when modifying and stabilizing the ground using the filler of the present invention, in the ground to be improved,
Ordinarily used water or muddy water containing soil, bentonite, cement, etc. is injected at high pressure to cut the inside of the ground,
In the obtained cavity, while leaving the sludge inside it, or after discharging it, pour the filling material of the present invention using a tremie tube, or fill it using a pump for concrete or mortar, Parts are replaced with the filler of the present invention and the filler is cured.

The amount of air mixed in the obtained filler is usually around 3%.

The amount of air mixed may vary depending on the mixing conditions such as the type and capacity of the kneading machine, kneading time, viscosity and temperature of the filler, etc. The amount of material used may be adjusted accordingly.

When the air mixture rate is large and the actual liquid volume is small, the amount of material used is small according to the actual liquid volume, and when the air mixture rate is small and the actual liquid volume is large, the material volume is changed according to the actual liquid volume. The more you use it, the better.

[Effect of the present invention]

The use of the filler of the present invention has the following effects as compared with the conventional method using a cement-based soil stabilizer.

1) The filling material of the present invention has not only good initial fluidity but also a small decrease with time, so that it can be uniformly filled in a target portion.

2) Since the filler of the present invention has a small breathing rate and hardly causes solid-liquid separation, a water layer due to the breathing of the filler does not occur at the boundary between the ground and the filled portion.

For this reason, the hollow portion in the ground can be completely replaced by the hardened body without leaving a portion that is not improved, so that the ground is surely remodeled and stabilized, and there is no risk of ground subsidence.

3) Since the filler of the present invention does not cause breathing,
Strength as designed-It is possible to create a hardened body having a moderately suppressed compressive strength that does not reduce the efficiency of excavation work at its stabilized location or excavation work in shield work, etc. The ground can be stabilized safely, more reliably, and with better workability.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

Cement, aggregate, water-reducing agent and water-soluble polymer were powder-mixed for about 1 minute at a ratio shown in Table 1 using a 1 m ³ forced kneading mixer as a mixing device, and then a predetermined amount of water was added. The mixture was kneaded for 180 seconds to obtain a slurry composition.

The following three evaluation items were tested on the obtained slurry composition.

(1) Fluidity immediately after kneading and after 60 minutes. (2) Breathing rate. (3) Compressive strength of the cured product. The test method for each evaluation item is as follows.

1) Fluidity: Vinyl chloride resin cylindrical frame (50 on a horizontal glass plate)
(mmφ, 100 mm height) is filled with 200 ml of the specimen, the frame is pulled up vertically, and the specimen spreads on the glass plate (diameter).
To measure.

2) Breathing rate: The specimen is poured into a mold (40 × 40 × 160 mm), the upper part is hermetically closed so that water does not evaporate, and allowed to stand. After 20 hours at 20 ± 1 ° C, the breathing water is generated. The amount (A) was measured and expressed as a percentage with respect to the amount (B) of water charged at the time of preparing the sample.

Breathing rate, (%) = (A / B) x 100, 3) Compressive strength of the cured product; Vinyl chloride resin cylindrical frame (50 mmφ, 100 mm height) is filled with the test sample and chlorinated so that water does not evaporate. After covering the upper part with a film made of vinylidene and sealing it, holding it at 20 ± 1 ° C in a thermostat and curing it for one day and then removing from the mold, then curing the obtained molded body in water at 20 ± 1 ° C for 28 days The compressive strength of was measured.

Table 1 shows the formulation and test results.

Table 1 will be described.

Comparative Examples 1-2: Comparative Examples 1 and 2 are good in terms of fluidity and breathing rate of the composition, but the compression strength of the obtained cured product is
Comparative Example 1 was as small as 6.0 kgf / cm ² , while Comparative Example 2 was 12 kg.
It is as large as 5 kgf / cm ^2, and neither of them is suitable for the filler intended by the present invention.

Comparative Examples 3 to 5: When the water reducing agent and the water-soluble polymer were not added, the initial fluidity immediately after the preparation of the composition was good, but the fluidity after 60 minutes was significantly reduced to 60 to 68 mm. Unsuitable as the filler of the present invention.

Comparative Example 6 and Example 19: When the water reducing agent was not added, the composition was good in terms of breathing rate and compression strength of the obtained cured product, but the fluidity of the composition was less than 100 mm, which was small. It is unsuitable as a filler for the purpose of the present invention. (Comparative example 6). Example 19 was a case where a water reducing agent was combined with the formulation of Comparative Example 6, the fluidity of the composition was improved, and the breathing rate and the compression strength of the obtained cured product were good.

Comparative Example 7 and Examples 13 to 16: When the amount of the water-soluble polymer added is small, the composition causes breathing. In addition, the fluidity of the composition decreases with time (13
8 → 112 (−26) mm, Comparative Example 7) is large as compared with Examples 13 to 16 and other Examples.

When the amount of the water-soluble polymer added is large, the viscosity of the composition is high, and the fluidity tends to be low. Filler 1m
The fluidity of the composition obtained in Example 16 in which the amount of the water-soluble polymer added per ³ is 8 kg is 100 mm, which is the limit value of the fluidity as the filler of the present invention.

In Example 20, sand (5 mm sieve-passed product) recovered by processing the slurry discharged by cutting the ground with high-pressure jet water in the above-ground portion was used as an aggregate.

Examples 1 to 20: In all cases, compositions having good initial fluidity, little decrease in fluidity with time, and a small breathing rate and hardly causing solid-liquid separation were obtained.

Once these compositions are cured, they are suitable for the purposes of the invention,
A cured product having a compressive strength in the range of 10 to 100 kgf / cm ² was obtained.

Either of them is suitable as a filler for the purpose of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09K 17/48 P // C09K 103: 00

Claims (2)

[Claims] 1. A composition for filling in the ground, which comprises a cement, an aggregate, a water-reducing agent, a water-soluble polymer, and water.
Cement-weight ratio is 2.2 or less, and the aggregate is a non-hydraulic material, and the ground remodeling filler is obtained by mixing each material in the following ratio by weight. (1) Cement: 160 to 400 parts by weight, (2) Aggregate: 1300 to 1500 parts by weight, (3) Water reducing agent: 0.5 to 15 parts by weight, (4) Water-soluble polymer: 1.5 to 8 parts by weight, (5) ) Water: 320 to 350 parts by weight. 2. Aggregates, fine gravel, gravel, gravel soil, sand, sandy soil, sandy silt, plaster sand, river sand, sea sand, which have passed through a 10 mm sieve,
The ground modification filler according to claim 1, which is at least one selected from the group consisting of mountain sand, silica sand, crushed stone powder, and mud obtained by cutting ground.