JPH02194891A - Treatment of water containing surplus excavation soil - Google Patents

Abstract

PURPOSE:To eliminate the fluidity of hydrous surplus excavation soil by adding a specific amount of anionic acrylic flocculant to said soil having a slump value of not less than 5cm and thereafter further adding a specific amount of quick lime and cement thereto for kneading. CONSTITUTION:1m<3> of the hydrous surplus soil resulting from excavation at tunneling site and having a slump value of not less than 5cm and an anionic acrylic flocculant dispersing liquid containing 0.1-5kg of pure polymer are made up and kneaded together. 1-100kg of quick lime, slaked lime and/or cement are additionally added to the aforesaid kneaded mass so as to be kneaded therewith. The fine particles having a diameter of not more than 100mum of an acrylic water-soluble polymer having a molecular weight of not less than one million and an anionization efficiency of 3-100mol% are suitable for use as the anionic acryl flocculant. Moreover, the quick lime and cement have a dehydrating action, exerting a synergetic effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a soil improvement method that eliminates the fluidity of water-containing excavated soil generated from tunnel construction sites using the Tonosho shield or propulsion method.

The excavated soil has fluidity so that it can be easily discharged from the cutter chamber, etc., and also has a property of maintaining watertightness. Fluidity is controlled by a slump test, and the slump value is often 5 crn or more. Since transportation by dump trucks and the like is also inefficient, various methods of eliminating fluidity have been investigated.

[Prior Art] In order to remove the fluidity of water-containing residual soil, methods such as leaving the residual soil naturally in a hopper or drying it in the sun are performed.

An example of adding chemicals is cement-based
200. Tokuko Sho 6 O-87813), lime-based (Toku Sho 6 O-87813)
2-31'8), super absorbent resin (JP-A-59-1354)
88) and the like, guar gum and the like are also used. In addition, a bubble shield method has been proposed in which bubbles are mixed in to maintain fluidity while lowering the moisture content, and the fluidity is removed by defoaming. (Special Publication No. 58-47560. Special Publication No. 59-49999) [Problems with conventional technology] When cement-based or lime-based solidifying agents are used alone in treatment methods using chemicals, the coagulated material becomes too hard, and the hopper There is a risk of blockage, etc.

The use of superabsorbent resins is expensive.

Soil treated with guar gum deteriorates over time due to the growth of mold and rot, so its uses are limited. Also, since it is a natural product, the price fluctuates greatly and there are concerns about supply.

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the inventors have found that:
We have arrived at the present invention.

The present invention applies an anionic acrylic polymer flocculant dispersion liquid to the water-containing excavation residue generated at the tunnel construction site in a polymer purity of 0.1 to 5% per 1 m3 of the water-containing excavation residue.
After adding and kneading, add lime-based coagulant to 1 to 100 kg.
It is characterized by adding g and kneading.

The acrylic polymer flocculant dispersion used here has a viscosity of 1
It is desirable that the concentration is 10,000 CP or less and the concentration is 10% or more.

If the viscosity is too high, the mixing will be uneven, and if the concentration is too low, a large amount of water will be added to the remaining soil, which will have a negative effect on preventing flow. The anionic acrylic polymer flocculant used in the present invention is selected from copolymers of acrylamide and acrylate salts, copolymers of acrylamide and 2-acrylamide alkyl sulfone salts, etc. with an anionization rate of 3 to 1 mol%. An acrylic water-soluble polymer having a molecular weight of 1 million or more, preferably 2 million or more is used, and is used in the form of fine particles with a particle size of 100tim or less dispersed in oil or salt aqueous solution.

The method for producing such a dispersion is known, and water-in-oil emulsions are disclosed in Japanese Patent Publication No. 34-10644 and Japanese Patent Publication No. 52-3941.
7 and Japanese Patent Publication No. 55-45783, and the method for producing a dispersion in a salt aqueous solution is described in Japanese Patent Publication No. 46-14907 and Japanese Patent Publication No. 6
2-2051 It is completely described in 1.

Lime-based, coagulant selected from quicklime, slaked lime and cement 1, fil! , or a mixture of two or more. These lime-based coagulants do not contain water,
In other words, it is preferable to use it in the form of powder, granules, small lumps, etc., and the amount is 1 to 100 kg/m3 for the water-containing excavated soil.
Add and knead. To mix the above acrylic polymer flocculant dispersion and lime-based coagulant into the water-containing excavated soil, use a kneader such as a continuous mixer or forced stirring mixer, a pond, a power shovel, a screw conveyor, or other civil engineering equipment. is also possible.

[Function] In the present invention, since the anionic acrylic polymer flocculant can be added as a low-viscosity fine particle dispersion, it is easily mixed into the water-containing excavated soil and adsorbed onto the surface of the soil particles. It is thought that the lime-based coagulant added next imparts calcium ions to the anionic hydrophilic groups in the soil particles and the polymer flocculant, thereby exhibiting a hydrophobic phenomenon. Also, quicklime and cement have a dehydrating effect, and it is possible that they have a synergistic effect.

[Examples] Next, the present invention will be explained by examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

Synthesis Example-1 A commercially available polymer flocculant (copolymer of sodium acrylate and acrylamide: anionization rate 20 mol%; molecular weight 6 million) was ground in a ball mill, and the fine powder that passed through a 200-mesh sieve was 9 times the amount A liquid obtained by dispersing Borie in ethylene glycol is referred to as Sample-1, and a liquid obtained by mixing 20 to 40 mesh portions obtained by sieving out the flocculant before pulverization in 9 times the amount of polyethylene glycol is referred to as Comparative Sample-1.

Synthesis Example-2 IQ equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube
Medium oil (specific gravity 0.83,
282g of sorbitan monooleate 108 (flash point: 138°C), Hypermer B-24620 manufactured by ICI Co., Ltd.
g and 0.3 g of lauroyl peroxide were added and dissolved at room temperature. Separately, a monomer solution was prepared by dissolving 262 g of acrylamide and 38 g of sodium acrylate in 328 g of ion-exchanged water, and then poured into the above-mentioned separable flask and stirred. After purging with nitrogen for 30 minutes and adjusting the internal temperature to 40°C, 0.6 ml of a 10% ascorbic acid aqueous solution was added to initiate polymerization.

After the internal temperature was maintained at 65° C. and the polymerization reaction was carried out for 5 hours, 20 g of polyoxyethylene nonylphenyl ether and 40 g of polyoxyethylene sorbitan triolate were added to the resulting emulsion, and the liquid was referred to as sample-2. Sample-2
The viscosity of the polymer was 980 cp at 20° C., and the molecular weight of the polymer was 3 million.

Synthesis Example-3 IQ equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube
300 g of medium oil (specific gravity 0.83, flash point 138°C) was placed in a five-neck sepaple flask, and 30 g of sorbitan monooleate and 2.2゛-azobisisobutyronitrile were added.
．． 3 g was added and dissolved at room temperature. Separately, acrylamide 1
After preparing a monomer solution in which 33 g of ammonium acrylate and 167 g of ammonium acrylate were dissolved in 325 g of ion-exchanged water, it was poured into the above-mentioned separable flask and stirred.

After purging with nitrogen for 30 minutes, the internal temperature was raised to 60°C and a polymerization reaction was carried out for 5 hours. A liquid obtained by adding and mixing 45 g of polyoxyethylene sorbitan triolate to the obtained emulsion is referred to as Sample-3. The viscosity of sample-3 is 11 at 25℃
00 cp and the molecular weight was 6 million.

0 Evaluation method The solidification state of the water-containing excavated soil is evaluated by measuring the penetration resistance value.

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

A penetration needle with a cross-sectional area of 7.5 cm2 was attached to a penetration resistance measuring device for measuring the setting time of concrete, and the penetration needle was penetrated 25 mm into the treated soil filled in a metal cylinder with a diameter of 15 cm for 10 seconds to measure the resistance value. Measure.

If the penetration resistance value is 0.3 kg/cm2 or more, generally no major difficulties will be recognized during transportation.

Example 1 Water-containing excavation residual soil collected from a sludge storage tank at a tunnel construction site using the Tonosho shield method of a certain civil engineering company was sieved to remove coarse lumps using a 5 mm sieve, and then subjected to a test.

The physical properties of the excavated soil are as follows.

The above excavated soil 3Q was mixed with a tabletop all-purpose mixer (JISR-5).
201, 9.1), added the amount of sample shown in Table 1, kneaded for a certain period of time, added quicklime, kneaded for an additional 30 seconds, and then measured the penetration resistance value. The results are shown in Table-1. All addition amounts are expressed as the pure weight of the chemical relative to the volume of the remaining water-containing soil.

Example-2 Using the same stirrer, the amount of chemicals listed in Table-2 was added to the same left-over soil as in Example-1, and after kneading for a certain period of time,
The penetration resistance value was measured. The results are shown in Table-2.

All addition amounts are expressed as the pure amount of the chemical relative to the volume of the remaining water-containing soil.

Table-1 Table-2

Claims (2)

[Claims] (1) 1 m of water-containing excavated soil with a slump value of 5 cm or more
Water-containing excavation characterized by adding and kneading an anionic acrylic flocculant dispersion having a polymer pure amount of 0.1 to 5 kg to ^3, and then adding and kneading 1 to 100 kg of quicklime, slaked lime, and/or cement. How to dispose of leftover soil. (2) Molecular weight of 1 million or more and anionization rate of 3 to 1
2. A method for treating water-containing excavated soil as claimed in claim 1, characterized in that a dispersion containing 00 mol% of an acrylic water-soluble polymer in the form of fine particles with a particle size of 100 μm or less is used.