JPH0649200B2 - Treatment method for wet excavated soil - Google Patents

Description

Description: [Industrial application] The present invention relates to a soil improvement method for eliminating the fluidity of water-containing excavated residual soil generated from a tunnel construction site of an earth pressure system shield or a propulsion method.

The above-mentioned excavated soil has a fluidity so as to be easily discharged from the inside of the cutter chamber and the like, and has a property of maintaining water stopping property. The fluidity is controlled by a slump test and often has a slump value of 5 cm or more. Since transportation by dump trucks etc. is also inefficient, various liquidity disappearance methods have been studied conventionally.

[Prior Art] In order to remove the fluidity of the hydrated residual soil, the residual soil hopper is left to stand naturally or is dried in the sun.

As an example of adding a chemical, a cement type (Japanese Patent Publication No. 62-4
200, Japanese Patent Publication 60-87813), lime type (Japanese Patent Publication 6)
2-318), a highly water-absorbent resin (JP-A-59-13548).
8) and the like are known, and guar gum and the like are used. Also, a bubble shield method has been proposed in which bubbles are mixed in order to maintain fluidity while reducing the water content, and fluidity is removed by defoaming. (JP-B-58-47560, JP-B-59-499999) [Problems of the prior art] In the treatment method using a chemical, the cement-based and lime-based solidifying agents deteriorate the working environment due to alkaline dust and block the hopper due to solidification over time. There is a risk of.

The use of super absorbent resin is expensive.

The application of guar gum-treated soil is limited because it deteriorates over time due to mold and rot. In addition, it is a natural product, and price fluctuations are large, so there is concern about supply.

[Means for Solving Problems] As a result of earnest studies to solve the above problems, the present inventor found that
The present invention has been reached.

In the present invention, the water-containing excavation residual soil generated at the tunnel construction site has an anionic acrylic polymer flocculant dispersion liquid and a cationic organic polymer coagulant aqueous solution as a total polymer content of the water-containing excavation residual soil. 01-0.5% by weight
It is characterized by sequentially adding and kneading.

It is desirable that the two liquids used here have a viscosity of 10,000 CP or less and a concentration of 10% or more.

If the viscosity is too high, the kneading becomes uneven, and if the concentration is too low, a large amount of water is added to the residual soil, which adversely affects flow prevention. The anionic acrylic polymer flocculant used in the present invention is selected from among copolymers of acrylamide and acrylate having an anionization rate of 3 to 100 mol%, copolymers of acrylamide and 2-acrylamidoalkyl sulfonate, and the like. An acrylic water-soluble polymer having a molecular weight of 1,000,000 or more, preferably 2,000,000 or more is applied, and is used in the state of being dispersed as fine particles having a particle diameter of 100 μm or less in an oil or an aqueous salt solution.

Methods for producing such dispersions are known, and water-in-oil emulsions are disclosed in JP-B-34-10644 and JP-B-52-3941.
7 and JP-B-55-45783, and a method for producing a dispersion in an aqueous salt solution is described in JP-B-46-14907 and JP-A-6-1987.
2-20511. On the other hand, the cationic organic polymer coagulant is a water-soluble polymer having an amino group or ammonium base in the molecule and having a molecular weight of 1,000,000 or less, and has a cation degree of 3 meq / g or more per polymer content.

Specifically, epihalohydrin, alkylene dihalide,
A reaction product obtained by condensing an amine or ammonia with an alkylene polyvalent epoxide or the like as a linking agent (Japanese Patent Publication No. 38-26).
794, JP-B-41-17965, JP-B-51-224
71, Japanese Examined Patent Publication No. 56-37844) or formaldehyde, or a condensation reaction product of dicyandiamide, melamine, guanidine or the like, or polyethyleneimine, polydimethyldiallylammonium chloride, dialkylaminoalkyl acrylate salt and / or its quaternary compound (co). Examples thereof include polymers and the like.

These cationic organic polymer flocculants are used in an aqueous solution state having a concentration of 10% or more.

In order to knead these two liquids into the water-containing excavated residual soil, it is possible to use a kneading machine such as a continuous mixer or a forced agitation mixer, as well as a civil engineering machine such as a power shovel or a screw conveyor. In the addition and kneading of the two-part hydrous residual soil in the present invention, it is necessary that one is uniformly mixed and then the other is added and kneaded, and simultaneous addition causes troubles such as insolubilization of the polymer.

The order of addition and kneading of the two liquids is arbitrary, but the properties of the final treated soil are more preferable when the anionic acrylic polymer coagulant dispersion liquid is added first. It is also possible to use a highly water-absorbent resin together in order to prevent the separation of water from the treated soil.

[Operation] The greatest feature of the present invention is that by using two kinds of polymers having different ionic properties in combination, the physical properties of the hydrous excavated residual soil are improved and solidified without revealing tackiness (pulling property). With the goal. Depending on the type of the remaining soil, even if only one of the anionic polymer and the cationic polymer is used, a certain degree of anti-fluidity effect can be imparted, but it is unsatisfactory in terms of tackiness (stretchability). Further, it is difficult to uniformly knead the powdery or highly viscous polymer into the hydrous residual soil.

In the present invention, the anionic acrylic polymer flocculant is added as a low-viscosity fine particle dispersion liquid, so that it is easily mixed with the water-containing excavated residual soil and adsorbed and coated on the surface of the soil particles. The cationic organic polymer coagulant electrically binds to the anionic groups of the polymer, insolubilizes and precipitates, and provides a strong adhesive force. A similar phenomenon is considered to occur when the order of addition is reversed.

EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Synthesis Example-1 1 equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube
300 g of medium oil (specific gravity 0.83, flash point 138 ° C.) was charged into a 4-necked separable flask, and 30 g of sorbitan monooleate and 0.3 g of 2.2′-azobisisobutyronitrile were added and dissolved at room temperature. . Separately, a monomer solution prepared by dissolving 133 g of acrylamide and 167 g of ammonium acrylate in 325 g of ion-exchanged water was prepared, and then poured into the aforementioned separable flask and stirred.

After performing nitrogen substitution for 30 minutes, the internal temperature was set to 60 ° C. and the polymerization reaction was performed for 5 hours. A liquid obtained by adding and mixing 45 g of polyoxyethylene sorbitan trioleate to the obtained emulsion is referred to as Sample-1. Sample-1 has a viscosity of 11 at 25 ° C.
The molecular weight of 00 cp was 6 million.

Synthesis Example-2 282 g of medium oil (specific gravity 0.83, flash point 138 ° C) was charged in the same separable flask as used in Synthesis Example-1, sorbitan monooleate 10 g, ICI Hypermer B-246 20 g and excess. Lauroyl oxide 0.3
g was dissolved in alkali at room temperature. Separately, 262 g of acrylamide and 38 g of sodium acrylate were dissolved in 328 g of ion-exchanged water to prepare a monomer solution, which was then poured into the aforementioned separable flask and stirred. After purging with nitrogen for 30 minutes, the internal temperature was adjusted to 40 ° C. and then ascorbic acid 10
% Aqueous solution 0.6 ml was added to initiate polymerization. Internal temperature 6
A liquid in which 20 g of polyoxyethylene nonyl phenyl ether and 40 g of polyoxyethylene sorbitan trioleate are added to the obtained emulsion after maintaining at 5 ° C. and performing a polymerization reaction for 5 hours is referred to as Sample-2. Sample-2 has a viscosity of 980 cp at 20 ° C. and a polymer molecular weight of 30.
It was 0,000.

Synthesis Example-3 Epichlorohydrin (370 g) was charged into a four-necked separable flask (1) equipped with a stirrer, a thermometer, a reflux condenser and a 500-ml dropping funnel, and the internal temperature under stirring was 10 to 45.
While adjusting to ℃, 40% dimethylamine aqueous solution 400
g was added dropwise. After the dropping was completed over 2 hours, 40 g of pentaethylenehexamine was added and the internal temperature was maintained at 65 to 70 ° C to carry out the condensation reaction. The condensation reaction was stopped by adding 225 g of a 25% aqueous solution of sulfuric acid while the viscosity of the contents was increased to 15,000 cp. The obtained polycationic aqueous solution was used as Sample-3.
Call. The viscosity of Sample-3 was 5300 cp at 25 ° C.

Example-1 A lump of coarse lumps was removed from a water-containing excavated residual soil collected from a sludge storage tank of a tunnel construction work site by a soil pressure shield construction method of a civil engineering company, and a test was performed.

The physical properties of the excavated soil are as follows.

4 kg of the above excavated soil was collected in a vinyl bag, sample-1 in the amount shown in Table-1 was added, and after kneading by hand for 1 minute, sample-3 was added and kneaded again to measure the penetration resistance value.
The results are shown in Table-1. The addition amounts are all values per polymer pure content with respect to the residual hydrated soil.

If the penetration resistance value is 0.3 kg / cm ² or more, generally no great difficulty is recognized in transportation.

The method of measuring the penetration resistance value in this test is as follows.

The penetration resistance measuring device for measuring the setting time of concrete was equipped with a penetration needle with a cross-sectional area of 7.5 cm ² and the resistance value was measured by allowing the penetration needle to penetrate 25 mm into the treated soil filled in a metal cylinder with a diameter of 15 cm for 10 seconds. To do.

Example-2 A penetration resistance value was measured by performing the same operation as in Example-1, except that Sample-3 was first added and kneaded to the same excavated soil as in Example-1, and then Sample-1 was added and kneaded. The results are shown in Table-2.

Example-3 A penetration resistance value was measured by performing the same operation as in Example-1, except that Sample-2 was first added and kneaded to the same excavated soil as in Example-1, and then Sample-3 was added. The results are shown in Table-3.

Comparative Example-1 A powdery polymer flocculant Hymolok SS-120 (Kyohin Co., Ltd.), which is composed of the same excavated soil as in Example 1 and is composed of an acrylamide-sodium acrylate copolymer (anionization rate: 20 mol%, molecular weight: 12 million) The puncture resistance value of the treated soil in which Sample-3 was added and kneaded after adding and kneading was measured. The results are shown in Table-4.

Comparative Example-2 The penetration resistance value of the treated soil obtained by only adding and kneading Sample-1 to the same excavated soil as in Example-1 was measured. The results are shown in Table-5.

Comparative Example-3 After adding and kneading Sample-1 to the same excavated soil as in Example-1,
The penetration resistance value of the treated soil to which a commercial liquid PAC (polyaluminum chloride) was added and kneaded was measured. The results are shown in Table-6.

Comparative Example-4 The penetration resistance value of the treated soil obtained by adding and kneading Sample-3 to the same excavated soil as in Example-1 was measured. The results are shown in Table-7.

Comparative Example-5 The penetration resistance value of the treated soil obtained by adding and kneading guar gum to the same excavated soil as in Example-1 was measured. The results are shown in Table-8.

Claims (1)

[Claims] 1. An acrylic polymer as shown in the following item (A) so that the total polymer net content is 0.01 to 0.5% by weight with respect to the hydrous excavated soil having a slump value of 5 cm or more. A method for treating water-containing excavated residual soil, characterized in that the fluidity of the residual soil is eliminated by successively adding and kneading the flocculant dispersion liquid and the aqueous solution of a cationic organic polymer flocculant shown in item (B) below. (A) The molecular weight is 1,000,000 or more and the anionization rate is 3
Dispersion liquid containing up to 100 mol% of an acrylic water-soluble polymer as fine particles having a particle size of 100 μm or less. (B) An aqueous solution of a cationic organic polymer coagulant having a cation degree of 3 meq / g or more and a molecular weight of 1,000,000 or less.