JP2012197630A - Method for processing foam soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for rapidly reducing flowability of foam soil without using a defoaming agent.SOLUTION: A method for processing foam soil comprises an initial step 102 and a subsequent step 104. In the step 102, the excavation soil produced by a foam shield construction is fed into a fracturing and foam breaking facility 11, so that the excavation soil is fractured and the foam in the excavation soil is broken. The bearing effect of the foam is thus eliminated, and the size of clod is reduced by the fracture of the excavation soil in the case of viscous soil. Consequently, a surfactant as a raw material of the foam can easily adsorb to soil particles. In the step 104, activated carbon is fed into the processed soil with broken foam. The activated carbon is uniformly dispersed in the processed soil of sandy soil and even of viscous soil due to the markedly-reduced size of the clod constituting the processed soil. The surfactant in the processed soil is thus efficiently adsorbed to the activated carbon. Disposal of waste soil including transportation and loading is more easily performed.

Description

  The present invention relates to a method for treating cellular soil generated in civil engineering construction work, particularly cellular soil generated in cellular shield construction.

  Among the sealed shields, the earth pressure shield method was excavated by the cutter head provided at the tip of the shield machine, and once the soil generated by the excavation was taken into the chamber, it was connected to the chamber. It is a construction method that stabilizes the face that spreads forward in front of the cutter head by keeping the earth pressure in the chamber properly while discharging with the screw conveyor, and because it requires less equipment than the muddy water type shield construction method, Widely used for underground tunnel construction in the city center.

  In particular, the bubble shield method is designed to inject cream-like air bubbles made of a special foam material made of a surfactant into the chamber, or to eject the air bubbles toward the face. Property and water stoppage can be improved.

  Therefore, adhesion of soil particles in the chamber and ejection of groundwater from the screw conveyor are prevented, and the earth pressure shield method can be applied to viscous ground and gravel ground.

  On the other hand, for the excavated soil discharged from the chamber via the screw conveyor, by adding an antifoaming agent to the excavated soil, the bubbles contained in the excavated soil are quickly extinguished to restore the fluidity, and the remaining soil Speeding up of processing is also performed.

JP 2005-021888 A

  However, the antifoaming agent is generally composed mainly of mineral oil, and there is a concern about the environmental load due to the inflow of mineral oil into the groundwater system or leaching into rivers or sea areas.

  For this reason, excavated soil to which an antifoaming agent composed mainly of mineral oil has been added is regarded as a problem when it is used as ocean dumping that directly affects the ecosystem, or when it is reused as embankment or landfill. In some cases, it must be treated as industrial waste.

  On the other hand, if the bubbles in the excavated soil are naturally extinguished without using an antifoaming agent, the above-described problem can be solved, but for that purpose, the excavated soil needs to be left standing for a certain period of time. However, in the bubble shield construction in which a large amount of excavated soil is generated, it is necessary to secure a large processing yard for the remaining soil treatment, and it is not economical as a measure in the city center.

  In addition, there is also a method of processing after improving the transport performance by mixing a solidifying agent with foam mixed soil with high fluidity, but because the processing cost is expensive and it can not be disposed of anywhere, It cannot be said that it is a highly versatile countermeasure.

  Because of the above points, especially in the case of recent large-section shields, since the amount of excavated soil discharged is enormous, a method for quickly and inexpensively treating bubble mixed soil is required. .

  In addition, although the surfactant itself has recently been biodegradable, biodegradation takes time, so by preventing the surfactant in the excavated soil from eluting, It is desirable to reduce the load on the environment such as the sea area as much as possible. In particular, when there is a concern that the surfactant concentration temporarily increases, the necessity of preventing elution becomes higher.

  Here, when the surface active agent is mixed in the excavated soil, the water content ratio of the excavated soil is once increased to release the surfactant into water, and then the water is collected and activated sludge is used. A method to restore the moisture content of excavated soil after biological treatment or oxidation treatment can be considered, but if the amount of treated soil is large, the economic burden is large and it is difficult to implement on site. It was.

  The present invention has been made in consideration of the above-described circumstances, and an antifoaming agent or a solidifying agent is used for cellular soil in which fluidity is high due to air bubbles, such as excavated soil generated in the bubble shield construction. An object of the present invention is to provide a method for treating cellular soil, which is capable of reducing fluidity quickly and without any problems.

  Another object of the present invention is to provide a method for treating cellular soil that can prevent elution of a surfactant that has been the source of bubbles.

  In order to achieve the above object, according to the method for treating cellular soil according to the present invention, the cellular soil is brought into contact with an impact-applying member that moves relative to the cellular soil, as described in claim 1. The bubbles in the cellular soil are broken while crushing.

  Also, the method for treating cellular soil according to the present invention is characterized in that the impact applying member is disposed at the base end of the shaft on the peripheral surface of the shaft held so that the material axis is substantially vertical and rotatable about the material axis. It is attached on the side, and while rotating the shaft, the cellular soil is brought into contact with the impact imparting member by naturally dropping the cellular soil into a swiveling range of the impact imparting member accompanying the rotation.

  Moreover, the processing method of the cellular soil which concerns on this invention arrange | positions the said shaft in the internal space of a cylindrical casing along the material axis | shaft, and comprised the said impact provision member with the chain member.

  Further, in the method for treating cellular soil according to the present invention, a plurality of crushing and foam breaking facilities composed of the shaft, the impact imparting member, and the cylindrical casing are installed in a row along the sediment transport direction, and the cylindrical shape Among the casings, a belt conveyor is disposed between the two cylindrical casings such that the nose is positioned below the upstream cylindrical casing and the tail end is positioned above the downstream cylindrical casing. is there.

  In addition, the method for treating cellular soil according to the present invention performs the crushing and foaming treatment by the impact applying member, and adding activated carbon to the treated soil at the same time as or after the crushing and foaming treatment. .

  In the method for treating cellular soil according to the present invention, when the cellular soil is naturally dropped, an air flow directed from below to above is generated in the internal space of the cylindrical casing.

  In the method for treating cellular soil according to the present invention, the cellular soil is excavated soil discharged from the chamber of the bubble shield.

  In the method for treating cellular soil according to the present invention, the cellular soil is brought into contact with the impact imparting member, whereby the cellular soil is broken or defoamed while the cellular soil is crushed.

  This eliminates the bearing effect due to the bubbles as the bubbles disappear, and in the case of viscous soil, the surface area of the entire foam soil increases due to the crushing of the foam soil. Is easily adsorbed and retained by the soil particles.

  Therefore, the treated soil after being brought into contact with the impact imparting member has a significantly lower fluidity than the cellular soil before contact, and thus it is possible to easily perform the remaining soil treatment such as transportation and loading.

  The impact imparting member may be any configuration as long as it can move relative to the cellular soil to contact the cellular soil and impart an impact. For example, the material axis is substantially vertical. The impact imparting member is attached to the peripheral surface of the shaft held so as to be rotatable around the material axis at the base end side, and the impact imparting member rotates within the swivel range as the shaft rotates. A cellular soil can be allowed to fall naturally.

  As long as the impact imparting member is capable of imparting impact to the cellular soil that naturally falls by turning around the shaft of the shaft as the shaft rotates, its structure and shape are arbitrary, and the whole Can be configured such that the entire body is formed of a flexible material, a plurality of steel pieces are connected in a long shape, and specifically, an impact applying member is configured by a steel rod material. Or a steel chain member, that is, a steel chain. By the way, when it is composed of a steel chain member, the chain member hangs down from the shaft when the shaft is stationary. While crushing, bubbles in the cellular soil are broken.

  Here, if the shaft is arranged so as to be along the material axis of the inner space of the cylindrical casing, the cellular soil scatters around when the impact is applied to the cellular soil by turning of the impact applying member. Can be prevented.

  When turning, a plurality of impact imparting members can be installed so as to extend in the radial direction at every predetermined angle, and a plurality of impact applying members can be installed along the vertical direction so that the naturally falling foam soil can receive an impact force one after another. It is possible to arrange in steps.

  The cellular soil was introduced from the upper opening of the cylindrical casing, and the impact imparting member was swung by the rotation of the shaft, so that it naturally dropped inside the cylindrical casing, and then the bubbles were broken from below the cylindrical casing. What is necessary is just to collect the treated soil, whether the foamed soil is thrown in continuously, intermittently, or whether the foamed soil is thrown by positioning the tail end of the belt conveyor above the cylindrical casing, The choice of whether to drop naturally from above the cylindrical casing using a hopper is also arbitrary.

  Here, a plurality of crushing and foam breaking facilities comprising a shaft, an impact applying member and a cylindrical casing are installed in a row along the earth and sand transport direction, and among those cylindrical casings, below the upstream cylindrical casing. If a belt conveyor is arranged between the two cylindrical casings so that the nose is positioned and the tail end is positioned above the cylindrical casing on the downstream side, the crushing breakage is carried out while carrying the cellular soil. It is possible to repeat the foam treatment in parallel.

  As described above, the fluidity of the treated soil can be reduced by the crushing and foaming treatment with the impact imparting member and returned to the state before the bubbles are added. If activated carbon is added to the treated soil at the same time as the foam breaking treatment, the surfactant in the treated soil is adsorbed and retained by the activated carbon, making it easier to handle residual soil such as transportation and loading. become.

  In addition, since the surfactant itself does not elute from the treated soil, it can be reliably prevented that the surfactant is exuded into the sea area or flowed into the groundwater system when dumped into the ocean or reused as embankment or landfill. The In particular, if a biodegradable surfactant is used, it is possible to more reliably avoid the influence on the environment in combination with the elution preventing action.

  The surfactant is not particularly limited as long as it can be adsorbed by activated carbon, and includes, for example, sodium alpha olefin sulfonate (hereinafter referred to as AOS). AOS, when dissolved at high concentrations in the waters where fish live, has the property of showing fish toxicity by adhering to the gills of the fish and causing dyspnea, but according to the present invention, it is adsorbed by activated carbon. Since the elution is prevented, combined with the good biodegradability, it can be reused as landfill or dumped in the sea.

  The activated carbon may be appropriately selected from the types of raw materials and the form of powder and granules so that the surfactant contained in the treated soil is reliably adsorbed and held. For example, powdered activated carbon derived from sawdust can be used, and uniform addition and mixing into the treated soil is facilitated by making the activated carbon powder.

  Here, when the cellular soil is naturally dropped in the crushing and foam breaking treatment by the impact applying member, the fluidity of the treated soil is further lowered by generating an air flow from the lower side to the upper side in the internal space of the cylindrical casing. I understood.

  This is because, in addition to the impact force by the impact imparting member, the air pressure caused by the air flow acts on the cellular soil, so that the bubbles existing in the cellular soil are more reliably broken or defoamed. I think that the.

  The crushing and foam breaking treatment using the impact applying member described above can be applied to all the cellular soil generated in the construction civil engineering work, but if applied to the excavated soil generated in the bubble shield construction, a large amount The excavated soil that is generated can be transported efficiently, and when activated carbon is added, the surfactant is prevented from elution, so that a large amount of treated soil can be dumped into the sea or used as embankment or landfill. It can be reused.

The flowchart which showed the implementation procedure of the processing method of the cellular soil which concerns on this embodiment. Schematic which showed the processing system for enforcing the processing method of the cellular soil which concerns on this embodiment. Schematic which showed the processing system for enforcing the processing method of the cellular soil which concerns on a modification. Schematic which showed a mode that the air flow which goes upwards from the downward direction in the cylindrical casing 12 was generated. Schematic which showed the processing system for enforcing the processing method of the cellular soil which concerns on a modification. The graph which showed the result of the verification test.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a cellular soil treatment method according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing an implementation procedure of the cellular soil treatment method according to the present embodiment, and FIG. 2 is a schematic diagram showing a treatment system for carrying out the treatment method. As can be seen from these drawings, in the method for treating cellular soil according to the present embodiment, first, excavated soil as cellular soil is removed from the chamber 6 of the shield machine 5 via the screw conveyor 1 connected to the chamber. Discharge (step 101).

  Here, the shield machine 5 is provided with a bubble supply line 7 for ejecting cream-like bubbles 8 formed of a special bubble material made of a surfactant toward the face, and excavation in the chamber 6 by the bubbles. Improves soil fluidity and water stoppage.

  Therefore, the adhesion of soil particles in the chamber 6 and the ejection of groundwater from the screw conveyor 1 are prevented, but the excavated soil discharged from the chamber 6 contains many bubbles, so that it is fluid as it is. It is so expensive that it is difficult to treat the remaining soil.

  Therefore, in this embodiment, by putting the excavated soil discharged from the screw conveyor into the crushing and foam breaking equipment 11 installed on the discharge side of the screw conveyor 1, the excavated soil in the excavated soil is crushed. Bubbles are broken (step 102).

  The crushing and foam breaking equipment 11 has a cylindrical casing 12, a shaft 13 arranged so as to be substantially vertical along its material axis and rotatable, and a base end side attached to the peripheral surface of the shaft. The shaft 13 can be rotated around its axis by a motor (not shown), and the chain member 14 includes a plurality of ring-shaped steel pieces. These are so-called chains that are connected to each other in a row, and as the shaft 13 rotates, the inner space of the cylindrical casing 12 is swung within the swirl range. When the excavated soil is thrown through the opening, the excavated soil is crushed by being impacted by the swirling chain member 14 while naturally falling in the cylindrical casing 12, Air bubbles in the Kezudo to foam breaking.

  In this way, the bearing effect due to the bubbles disappears with the disappearance of the bubbles, and in the case of viscous soil, the clots of the excavated soil become smaller and the surface area of the entire excavated soil increases, so the raw material of the bubbles It becomes easy to be adsorbed and held on the soil particles.

  Therefore, the treated soil after being brought into contact with the chain member 14 has a significantly lower fluidity than the excavated soil before the contact, and it is possible to easily perform the remaining soil treatment such as conveyance and loading.

  A plurality of chain members 14 can be installed so as to extend in the radial direction at every predetermined angle, such as four at 90 ° and three at 120 °. In addition, the chain member 14 is attached with a weight to its tip so that a sufficient impact force can be applied to the excavated soil, and in the vertical direction so that an impact force can be applied to the excavated soil that falls naturally. It is desirable to arrange in multiple stages along.

  Next, the treated soil in which bubbles are broken by the crushing and foam breaking equipment 11 is dropped on the belt conveyor 15 positioned at the nose side below the cylindrical casing 12 and conveyed backward, and a line mixer at the tail end side. 2 (step 103).

  Next, activated carbon is put into the line mixer 2, and the activated carbon is uniformly dispersed in the treated soil by stirring and mixing with the treated soil in the line mixer (step 104).

  The activated carbon may be supplied from an activated carbon storage tank (not shown) installed on the ground via an activated carbon supply line 3 connected to the line mixer 2. For example, powdered activated carbon derived from sawdust is used. Is possible.

  In this way, when activated carbon is added to the treated soil after the crushing treatment and foam breaking treatment, the size of the soil mass constituting the treated soil is remarkably reduced even in the case of sandy soil as well as viscous soil. Therefore, the activated carbon is uniformly dispersed in the treated soil, the surfactant in the treated soil is efficiently adsorbed and held on the activated carbon, and the remaining soil treatment such as transportation and loading is further facilitated.

  Next, the soil after the activated carbon treatment is carried out to the rear of the tunnel by the belt conveyor 4 arranged on the downstream side of the line mixer 2 (step 105).

  As described above, according to the method for treating cellular soil according to the present embodiment, the excavated soil as the cellular soil discharged from the chamber 6 of the shield machine 5 is put into the crushing and foam breaking equipment 11 so that the shaft Since the excavated soil is crushed by bringing it into contact with the chain member 14 that rotates with the rotation of 13 and the bubbles in the excavated soil are broken or defoamed, the soil properties such as sandy soil or viscous soil Regardless of this, the bearing effect due to the bubbles disappears, and in the case of cohesive soil, the surfactant is adsorbed and held by the finely crushed excavated soil mass.

  Therefore, the treated soil after coming into contact with the chain member 14 has a significantly lower fluidity than the excavated soil before the contact, and thus a large amount of oil can be used without using an oil-based antifoaming agent that has been conventionally used. In addition to returning the excavated soil to its original fluidity, it is possible to easily perform residual soil processing such as transportation and loading. In addition, a vast processing yard that is essential for natural defoaming is not required.

  Further, according to the method for treating cellular soil according to the present embodiment, since activated carbon is added to the treated soil after the crushing and foam breaking treatment, the surfactant in the treated soil is adsorbed and held by the activated carbon, and is transported. And the remaining soil processing such as loading becomes even easier.

  Further, since the surfactant is surely adsorbed on the clot or activated carbon that has been remarkably reduced by the crushing treatment, the surfactant does not elute from the treated soil. Therefore, in the case of ocean dumping or reuse as embankment or landfill, surfactant exudation into the sea area and inflow into the groundwater system are reliably prevented. In particular, if a biodegradable surfactant is used, it is possible to more reliably avoid the influence on the environment in combination with the elution preventing action.

  In the present embodiment, the example in which the method for treating cellular soil according to the present invention is applied to the bubble shield construction has been described. However, the present invention is not limited to such construction, and the soil has improved fluidity due to the incorporation of bubbles. It is possible to apply to all cases where it is necessary to restore the original liquidity.

  Further, in this embodiment, activated carbon is added to the treated soil after the crushing and foam breaking treatment is finished. Because the dimensions are much smaller, the total surface area is much larger than the excavated soil. Therefore, without adding activated carbon, the activated carbon addition step may be omitted as long as the surfactant can be prevented from being eluted only by adsorption to the soil blocks or soil particles constituting the treated soil.

  In particular, when the excavated soil is sandy soil, the amount of bubbles added to obtain the required fluidity is essentially small. For this reason, if the surfactant can behave as a liquid by the crushing and foaming treatment described above (the state in which air is expelled by the foaming), the treatment is combined with the high permeability coefficient of sandy soil. The surfactant in the soil is easily discharged from the treated soil while the treated soil is being transported by a belt conveyor or loaded in the stock yard, and thus the treated soil is more securely tightened. It can be expected that not only it can be brought into a state, but also prevention of surfactant elution by adding activated carbon becomes unnecessary.

  Further, in this embodiment, the chain member 14 constitutes an impact applying member, and the chain member is attached to a shaft disposed in the internal space of the cylindrical casing and along the material axis thereof. In place of the chain member, for example, a rod material, a steel wire, a propeller-like blade material, etc. may be used, and if a physical impact can be applied to the naturally falling cellular soil, the configuration and form of the impact applying member Is optional.

  Furthermore, in the method for treating cellular soil according to the present invention, the cellular soil is brought into contact with an impact applying member that moves relative to the cellular soil, whereby the cellular soil is broken while breaking the cellular soil. If foaming can be performed, the relative movement of the impact applying member with respect to the cellular soil can be arbitrarily selected from known relative moving means. For example, the impact applying member is rotated. Instead, it is possible to adopt a configuration in which reciprocating motion is performed in a horizontal plane, and the cellular soil is naturally dropped into the reciprocating motion range.

  Moreover, in this embodiment, although the example which uses the crushing bubble breaking equipment 11 single-piece | unit was demonstrated, as shown in FIG. 3, while installing the crushing bubble breaking equipment 11 in a row along the earth and sand conveyance direction, those You may make it arrange | position the belt conveyor 21 respectively.

  Each belt conveyor 21 is configured such that the nose thereof is positioned below the cylindrical casing 12 constituting the upstream crushing and foaming equipment 11, and the tail end thereof constitutes the downstream crushing and foaming equipment 11. It arrange | positions so that it may be located above the cylindrical casing 12 to perform.

  If it does in this way, it will become possible to repeat crushing foam breaking processing, conveying excavated soil as cellular soil discharged from the inside of chamber 6 of shield machine 5 back.

  In the case where the crushing and foaming treatment is repeatedly performed as described above, the line mixer 2 is installed on the downstream side of the crushing and foaming equipment 11 on the most downstream side, whereby the cylinder constituting the crushing and foaming equipment on the most downstream side. Activated carbon is added to the treated soil put into the cylindrical casing 12 in advance, or activated carbon is added to the treated soil discharged from the cylindrical casing.

  In such a configuration, the surfactant can be reliably adsorbed on the activated carbon after the crushing treatment and the bubble breaking treatment by impact application are sufficiently performed.

  Although not particularly mentioned in the present embodiment, as shown in FIG. 4, an air supply pipe 41 communicating with the internal space of the cylindrical casing 12 is connected to the vicinity of the lower end of the cylindrical casing and the base of the air supply pipe is provided. An air supply blower 42 is connected to the end side, and an exhaust pipe 43 that communicates with the internal space of the cylindrical casing 12 is connected to the vicinity of the upper end of the cylindrical casing, and an exhaust blower 44 is connected to the front end side of the exhaust pipe. You may do it.

  In such a configuration, when the air supply blower 42 and the exhaust blower 44 are operated, an air flow directed upward from below is generated in the internal space of the cylindrical casing 12, and the air flow is naturally excavated in the cylindrical casing 12. The air is applied to the excavated soil by hitting the soil.

  Therefore, in addition to the impact force of the chain member 14, the air pressure due to the air flow acts on the excavated soil, and thus bubbles existing in the excavated soil are more reliably broken or defoamed. It becomes possible to further reduce the fluidity of the soil.

  Further, in the present embodiment, in the application to the bubble shield construction, the example in which the excavated soil crushing and foaming processing, the addition of activated carbon and the stirring and mixing processing are performed in the tunnel excavated by the shield machine 5 has been described. When the foam facility 11 does not fit in the tunnel, the excavated soil may be subjected to crushing and breaking processing, addition of activated carbon, and stirring and mixing processing on the ground.

  FIG. 5 shows such a modified example, and also in the modified example, as in the above-described embodiment, the foamed soil as the cellular soil is connected via the screw conveyor 1 connected to the chamber from the chamber 6 of the shield machine 5. The excavated soil is discharged. In this modification, after excavating the excavated soil to the outside of the mine via a belt conveyor or a slurry pump, the excavated soil is sequentially put into the three crushing and foam breaking facilities 11 installed on the ground. As a result, bubbles in the excavated soil are broken while the excavated soil is crushed.

  Even if it is such ground treatment, the effect is the same as that of the above-mentioned embodiment, the disappearance effect of the bearing effect by bubble breakage, and the adsorption retention of the surfactant on the soil particles by crushing in the case of viscous soil Due to the action, the fluidity of the treated soil is significantly lower than that of the excavated soil, and the remaining soil treatment such as transportation and loading becomes easy.

  In addition, as in FIG. 3, a plurality of crushing and foam breaking equipments 11 are installed in a row along the sediment transport direction, and belt conveyors 21 are respectively arranged between them, and excavated soil from the chamber 6 is provided. On the other hand, the crushing and foaming treatment can be repeatedly performed, but the activated carbon is added to the treated soil put into the cylindrical casing 12 constituting the crushing and foaming equipment 11 on the most downstream side. Then, after the effect of extinguishing the bearing effect due to the above-mentioned bubble breakage and the effect of adsorbing and retaining the surfactant to the soil particles due to crushing are fully exhibited, the surfactant can be surely adsorbed to the activated carbon. It becomes.

  After the activated carbon treatment is completed, the soil may be discarded from the excavation site and then dumped into the ocean, or may be reused appropriately as embankment or landfill.

[Verification test]
Next, a demonstration test was conducted on the change in fluidity of the cellular soil according to the present invention.

  In the verification test, first, 50 bubbles were produced by foaming 15% of a 1.5% solution of sodium alpha olefin sulfonate (hereinafter referred to as AOS) into a drilling soil made of clay soil (Dotan). % Was added and mixed with a mixer to prepare a bubble-mixed soil.

Next, the change of the cone index when such bubble mixed soil was put into the crushing and foam breaking equipment 11 was examined. The results are shown in Table 1 and FIG.

As can be seen from these charts, when the chain member 14 is simply thrown into the crushing and foam breaking equipment 11 without turning (case 1), the cone index is 20 to 30 kN / m ² even if the throwing is repeated five times. However, it was far below the target value of 200 kN / m ² . Further, in addition to the above conditions, the case where air blowing (room temperature) was also performed (case 2), the results were almost the same. Here, the target value of 200 kN / m ² is based on the point that it can be transported by dump truck as general residual soil.

On the other hand, when the turning speed of the chain member 14 is 500 rpm (cases 3 to 4), in the case 3 where the air is not blown, the cone index is about 100 kN / m ² , but in the case 3 where the air is blown, the cone index is 3 times. By repetition, the target value of 200 kN / m ² could be cleared.

  From the above results, it is possible to improve the fluidity of the cellular soil by applying an impact force by the crushing and foam breaking equipment 11. It was found that the fluidity can be sufficiently improved.

In the case where the air is not blown, the cone index is only about 100 kN / m ² , but it is estimated that the target value of 200 kN / m ² can be surely cleared in the case of sandy soil instead of viscous soil, for example. it can.

DESCRIPTION OF SYMBOLS 1 Screw conveyor 2 Line mixer 3 Activated carbon supply line 4 Belt conveyor 5 Shield machine 6 Chamber 7 Bubble supply line 11 Crushing bubble breaking equipment 12 Cylindrical casing 13 Shaft 14 Chain member (impact imparting member)
15, 21 Belt conveyor

Claims (7)

A method for treating cellular soil, comprising bringing the cellular soil into contact with an impact applying member that moves relative to the cellular soil to break the bubbles in the cellular soil while breaking the cellular soil. The impact applying member is attached to the peripheral surface of the shaft that is held so that the material axis is substantially vertical and rotatable around the material axis, and the shaft rotates while rotating the shaft. The method for treating cellular soil according to claim 1, wherein the cellular soil is brought into contact with the impact imparting member by allowing the cellular soil to naturally fall into a swiveling range of the impact imparting member associated with the impact imparting member. The method for treating cellular soil according to claim 2, wherein the shaft is disposed so as to be along the material axis of the internal space of the cylindrical casing, and the impact applying member is constituted by a chain member. A plurality of crushing and foam breaking facilities comprising the shaft, the impact applying member, and the cylindrical casing are installed in a row along the earth and sand transport direction, and among those cylindrical casings, below the upstream cylindrical casing. The method for treating cellular soil according to claim 3, wherein a belt conveyor is disposed between the two cylindrical casings so that the nose is positioned and the tail end is positioned above the downstream cylindrical casing. The foamed soil according to any one of claims 1 to 4, wherein activated carbon is added to the treated soil simultaneously with or before or after the fractured foaming treatment while performing the fractured foaming treatment with the impact imparting member. Processing method. The method for treating cellular soil according to any one of claims 1 to 4, wherein when the cellular soil is naturally dropped, an air flow directed from below to above is generated in an internal space of the cylindrical casing. The method for treating cellular soil according to any one of claims 1 to 6, wherein the cellular soil is excavated soil discharged from a chamber of a bubble shield.

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