JP2016089140A - Foundation improvement material and foundation improvement method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a liquefaction phenomenon during earthquake, and prevent ocean pollution due to flowing of radioactive substances included in underground water from Fukushima Daiichi Nuclear Power Station and the like to the ocean.SOLUTION: A plaster slurry which is generated as a by-product of an exhaust gas desulfurizer in a ground layer, and a sodium silicate solution being water glass are mixed for chemical reaction, then the mixture is pressed in the underground and solidified, clog of sand and the ground layer are solidified and shielded for preventing liquefaction phenomenon during earthquake, and entry of the underground water of Fukushima Daiichi Nuclear Power Station and the like into a building of the nuclear power station can be prevented.

Description

  The present invention relates to a ground improvement treatment method for preventing ground liquefaction due to an earthquake and a ground shielding method for preventing diffusion of radioactively contaminated water generated by an accident at the Fukushima Daiichi Nuclear Power Station into the ocean. .

  Conventionally, as a countermeasure against earthquake liquefaction, an aqueous solution of sodium silicate, which is water glass, and a solidifying agent are mixed and pressed into the ground to solidify the ground. At the Fukushima Daiichi NPS, if the water level of radioactively contaminated water containing cesium, strontium, tritium, etc. staying underground in the power plant due to the accident increases due to the water pressure of the natural groundwater vein, There is a possibility that water may flow to the ocean through the groundwater vein path, and in order to prevent this, there is a plan to prevent the intrusion of groundwater by installing frozen soil walls around the power plant building.

Therefore, there are the following problems.
(B) There was a problem of liquefaction of the ground near the coast due to the shaking of the ground due to the earthquake.
(B) The Fukushima Daiichi nuclear power plant is located near the coast, and the underground of the power plant is a passage for natural ground water from the upstream mountain, there is a gap in the underground pit bulkhead, and the upstream side in the pit There was a problem that the groundwater flowed into the building due to the natural groundwater pressure from the mountain.
(C) When groundwater flows into the underground pit of the Fukushima Daiichi Nuclear Power Station, the groundwater mixes with the high-concentration radioactive material accumulated in the pit and may flow to the sea through the groundwater veins due to the water pressure in the pit. There was a problem that there was.

Means for solving the above problems are as follows.
(B) As a countermeasure against liquefaction in the event of an earthquake, the gypsum slurry generated as a by-product of the flue gas desulfurization device and the aqueous solution of sodium silicate, which is water glass, are mixed and chemically reacted in the underground soil. Solidify.
(B) The gypsum slurry generated as a by-product of the flue gas desulfurization unit and the sodium silicate aqueous solution, which is water glass, are mixed into the groundwater vein soil around the Fukushima Daiichi Nuclear Power Station to cause a chemical reaction. Solidify and shield the injection site.

The present invention has the following effects.
(B) As a countermeasure against liquefaction in the event of an earthquake, gypsum slurry generated as a by-product of flue gas desulfurization equipment and water glass sodium silicate aqueous solution are mixed and chemically reacted and injected into the underground soil. Since the viscosity of the solution is very small like water, it diffuses and disperses widely in the underground soil. Moreover, since the particle size of the desulfurized gypsum is large, the reaction with sodium silicate is delayed, the time for gelation can be increased to 1 hour or more, and the soil can be solidified over a wide range on the soil at the injection site. Further, since the treatment solution enters and disperses into the gaps in the soil, there is an effect that the strength of the solidified soil is increased.
(B) The gypsum slurry generated as a by-product of the flue gas desulfurization device and the water glass sodium silicate aqueous solution are mixed into the groundwater vein soil around the Fukushima Daiichi Nuclear Power Station and subjected to a chemical reaction and injected. This treatment solution is passed through the underground sand, mud in the groundwater vein, or the gap between the pits of the nuclear power plant, where it solidifies, clogs and shields, so that the groundwater enters the power plant building. There is an effect of preventing.

Embodiments of the present invention will be described below.
(B) A 9wt% gypsum slurry generated as a by-product of flue gas desulfurization equipment and an aqueous sodium silicate solution of 30wt% water glass are mixed and chemically reacted to underground layers and sand that may be liquefied. Press-fit to solidify the soil in the ground.
(B) Mixing 9wt% gypsum slurry generated as a by-product of flue gas desulfurization equipment and sodium silicate aqueous solution of 30wt% water glass in the groundwater vein soil around the Fukushima Daiichi Nuclear Power Station Chemical reaction and press-fitting to solidify and shield the earth and sand.

Claims (3)

  A mixture of gypsum powder slurry with a particle size generated as a by-product from a lime-gypsum wet flue gas desulfurization device and an aqueous solution of sodium silicate called water glass are mixed and subjected to a chemical reaction, which is then pressed into the soil. By reducing the pH value of the aqueous sodium silicate solution from alkaline to neutral, the ground soil improvement material and the ground improvement treatment method are characterized by solidifying the ground soil injected.   A 3% to 15% slurry of gypsum powder with a particle size generated as a by-product from a lime gypsum wet flue gas desulfurization apparatus is mixed with an aqueous solution of sodium silicate called water glass to cause a chemical reaction. The soil improvement material and its ground improvement treatment are characterized by lowering the pH value of the aqueous sodium silicate solution from alkaline to neutral by press-fitting it into the soil, and solidifying the injected soil. Method.   A 5% to 10% slurry of a gypsum powder with a particle size generated as a by-product from a lime gypsum wet flue gas desulfurization apparatus is mixed with an aqueous solution of sodium silicate called water glass to cause a chemical reaction. The soil improvement material and its ground improvement treatment are characterized by lowering the pH value of the aqueous sodium silicate solution from alkaline to neutral by press-fitting it into the soil, and solidifying the injected soil. Method.