JP2016098608A - Sand production processing system and shield excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sand production processing system and a shield excavator enabling a medicine to evenly penetrate into the sand production in order to sufficiently reduce elution of a processing material in the sand production by the medicine.SOLUTION: A sand production processing system 1 crushes a sand production generated by digging a soil layer and has a sand production processing mechanism 30 capable of adding a medicine, which reduces elution of a processing material such as arsenic into the sand production, to the sand production. The shield excavator 20 has at least the sand production processing system 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an excavation residual soil processing system and a shield excavator.

When building a tunnel by the shield method, arsenic derived from nature may appear in the cross section of the soil layer, and arsenic may be contained in the excavated soil. In that case, there is a problem that the excavated residual soil becomes contaminated soil unless any treatment is performed when the excavated residual soil is disposed of.
As one of the processing methods for such excavation residual soil containing arsenic, for example, there is a processing method for preventing arsenic from eluting by adding a chemical to the excavation residual soil.

For example, Patent Document 1 discloses a treatment for insolubilizing heavy metals in soil by adding and stirring any one of trivalent aluminum salts, aluminum sulfate, aluminum nitrate and alum, to heavy metal-contaminated soil. A method is disclosed.
In Patent Document 2, iron powder and an aluminum salt are added to soil contaminated with one or more of an organic halogen compound and a halogen element and heavy metal, and then adjusted to an alkaline region. A processing method is disclosed in which elements and heavy metals are entrained and then a neutral cement is added.

Japanese Patent No. 3227487 Japanese Patent No. 3867002

  However, when the soil layer is highly viscous, the excavated residual soil is dumped in a lump, and it is difficult for the treatment methods disclosed in Patent Documents 1 and 2 to penetrate the chemical evenly into the excavated residual soil. It is. As a result, the chemical reaction between the chemical and arsenic in the excavated soil does not proceed sufficiently, and the arsenic elution suppression effect by the chemical is not fully exhibited. There is a problem that it ends up.

  The present invention has been made in view of the above circumstances, and in order to sufficiently exhibit the elution suppression effect of the treatment target substance in the excavated residual soil by the chemical, the chemical can be evenly penetrated into the excavated residual soil. The purpose is to provide an excavation residual soil treatment system and a shield excavator.

The excavation residual soil processing system according to claim 1, further comprising an excavation residual soil treatment mechanism configured to crush the excavation residual soil generated when excavating the soil layer and to add a chemical to the excavation residual soil. To do.
According to the excavation residual soil processing system, when the excavation residual soil is introduced into the excavation residual soil processing mechanism, the excavation residual soil is reliably crushed and becomes finely granular. By adding the chemical | medical agent which suppresses the elution from the excavation residual soil of the process target substance which exists in the excavation residual soil to such excavation residual soil, the chemical | drug | medicine penetrate | infiltrates uniformly to the inside of excavation residual soil. “Fine-grained” refers to all states that change from a dry state to a mud-like state close to a liquid depending on the moisture content.

3. The excavation residue processing system according to claim 2, wherein the excavation residue treatment mechanism includes an introduction unit that introduces the excavation residue, a chemical addition unit that adds the chemical to the excavation residue, and the excavation introduced from the introduction unit. A crushing portion for crushing the remaining soil and a derivation portion for deriving the excavated residual soil are provided.
According to the excavation residual soil processing system, the excavation residual soil is introduced into the crushing portion via the introduction portion, and is crushed and refined. Then, a chemical | medical agent is added to fine granular excavation residual soil from a chemical | medical agent addition part. The excavated residual soil to which the chemical is added is led out from the excavating portion to the outside of the excavated residual soil treatment system. With such a smooth process, the chemical penetrates evenly into the excavated soil.

In the excavation residual soil processing system of Claim 3, the said chemical | medical agent addition part is installed in the part before excavation residual soil passes the said crushing part, or the part after excavation residual soil passes the said crushing part. It is characterized by.
According to the shield excavation residual soil treatment system, if the chemical addition unit is installed in a portion before the excavation residual soil passes through the crushing portion, the excavation residual soil to which the chemical has been added in advance is crushed by the crushing portion and becomes fine granular. At that time, the excavation residue and the chemical are kneaded, and the chemical penetrates evenly into the excavation residual soil. In addition, if the chemical addition part is installed in the part after the excavation residual soil passes through the crushing part, the chemical is added to the excavation residual soil finely divided in the crushing part, and the chemical penetrates evenly into the excavation residual soil. .

According to a fourth aspect of the present invention, there is provided a shield excavator comprising the excavation residual soil processing system.
According to the above shield excavator, the excavated residual soil generated in the shield excavator is introduced into the excavated residual soil treatment system, so that the chemical agent penetrates evenly into the excavated residual soil and the excavated residual soil is processed smoothly.

The shield excavator according to claim 5, wherein a excavation mechanism excavating a soil layer, a first excavation portion for excavating the excavation residual soil generated by the excavation mechanism toward the excavation residual soil treatment system, and the excavation residual soil And a second soil discharging portion for discharging the remaining excavated soil derived from the processing system to the outside.
According to the shield excavator, the excavated residual soil generated by the excavating mechanism is discharged to the excavated residual soil processing system by the first soil discharging portion, and introduced into the excavated residual soil processing system and processed. The treated excavation remaining soil is discharged outside the shield excavator by the second earth discharging portion. With such a smooth process, the chemical penetrates evenly into the excavated soil.

  According to the excavation residual soil treatment system and shield excavator of the present invention, the chemical can be uniformly permeated into the excavation residual soil, so that the chemical reaction between the excavation residual soil and the chemical is efficiently promoted, and the chemical excavation in the excavation residual soil by the chemical is performed. The elution suppression effect of the target substance is sufficiently exhibited.

It is a schematic sectional drawing which shows the shield excavator which is one Embodiment of this invention. It is a horizontal sectional view showing a part of excavation residual soil processing system which is one embodiment of the present invention. It is a longitudinal cross-sectional view which shows a part of excavation residual soil processing system which is one Embodiment of this invention, and is a figure corresponding to the case where it views on the XX line shown in FIG. It is a longitudinal cross-sectional view which shows a part of excavation residual soil processing system which is one Embodiment of this invention, and is a figure corresponding to the case where an arrow is taken by the YY line shown in FIG. It is a graph which shows the change of the arsenic elution amount with respect to the polyaluminum chloride (PAC) addition amount from the earth and sand in an Example.

  Hereinafter, one embodiment of the excavation residual soil processing system and shield excavator according to the present invention will be described with reference to FIGS. Note that the drawings used in the following description are schematic, and the ratios of length, width, and thickness are not necessarily the same as actual ones, and can be changed as appropriate.

  In the following, for example, when tunnels are constructed, the amount of arsenic present in the excavated residual soil generated by excavating the soil layer is suppressed to a threshold value or less, and post-processing such as backfilling of the excavated residual soil is made possible. Assuming the case, an excavation residual soil treatment system and a shield excavator according to an embodiment (hereinafter simply referred to as the present embodiment) to which the present invention is applied will be described.

FIG. 1 is a schematic sectional view showing a shield excavator 20 according to the present embodiment.
As shown in FIG. 1, the shield excavator 20 is configured to include at least the excavation residue processing system 1 of the present embodiment. Further, the shield excavator 20 includes an excavation mechanism 50, a first earth discharging part 52, and a second earth discharging part 54. In addition, illustration of the detailed structure of the crushing part 22 is abbreviate | omitted in FIG.
Hereinafter, the components of the shield excavator 20 will be described in the order in which they are arranged along the direction in which the excavated residual soil is discharged (the direction of the arrow D1 shown in FIG. 1).

  The excavation mechanism 50 constructs the primary lining S by assembling the segments with an erector (not shown) at the rear of the cylindrical skin plate 2 in the direction of the arrow D1 in the same manner as when excavating with various conventional shield excavators. This is a mechanism for excavating the shield excavator 20. In the excavation mechanism 50, the mud clay chamber 7 is provided behind the annular and face plate type cutter 10 having the face 13 in the direction of arrow D <b> 1. The mud clay chamber 7 is filled with a mud clay material injection pipe 8 from a mud clay material injection pipe 8 and converts the excavated soil into mud by powerful mixing with a mixing blade (not shown). The face 13 is stabilized by balancing and the excavation is performed. At the time of excavation, when naturally derived arsenic appears in the cross section of the soil layer, the excavated residual soil contains arsenic.

The first earth removing unit 52 is configured to be able to remove the excavated residual soil generated by the excavating mechanism 50 toward the excavated residual soil processing system 1, and includes screw conveyors 60, 62, and 64 sequentially connected to the excavating mechanism 50. One end 60 a of the screw conveyor 60 is connected to the bottom of the mud clay chamber 7. The other end 60 b of the screw conveyor 60 is connected to one end 62 a of the screw conveyor 62 from above via a connecting pipe 61. The other end 62 b of the screw conveyor 62 is connected to the one end 64 a of the screw conveyor 64 from above via a connecting pipe 63. The other end portion 64 b of the screw conveyor 64 is connected to the introduction portion 21 of the excavation residual soil processing system 1.
Accordingly, the excavated residual soil accumulated in the mud clay chamber 7 of the excavation mechanism 50 is introduced into the screw conveyor 60 and conveyed in the direction of the arrow D1 by the screw conveyors 60, 62, 64, and then introduced into the introduction unit 21 of the excavated residual soil treatment system 1. It is earthed.
The configuration of the first earth removing unit 52 is not particularly limited as long as the excavated residual soil can be excavated toward the excavated residual soil processing system 1, and is attached to the conveyance pipe and the conveyance pipe made of metal or resin, for example. The excavation residual soil conveying means may be used.

  One end 62a of the screw conveyor 62 and one end 64a of the screw conveyor 64 are supported by a gantry M provided inside the primary lining S. Inside the gantry M, for example, a power source (not shown) for operating the excavation mechanism 50, the first soil removal unit 52, the excavation residual soil processing system 1, and the second soil removal unit 54 are accommodated.

The excavated residual soil treatment system 1 includes a excavated residual soil treatment mechanism 30 that crushes excavated residual soil.
The excavated residual soil processing mechanism 30 includes an introduction unit 21, a crushing unit 22, a chemical addition unit 23, and a derivation unit 25.

  The introduction part 21 is configured to introduce the excavated residual soil and to convey it to the crushing part 22. The introduction part 21 is composed of, for example, piping, and one end part 21 a of the introduction part 21 is connected to the other end part 64 b of the screw conveyor 64, and the other end part 21 b of the introduction part 21 opens to the crushing part 22. . In addition, one end portion 32b of a connecting pipe 32 of a drug addition portion 23 described later is connected to the vicinity of the other end portion 21b of the introduction portion 21.

  The drug addition unit 23 is configured to be able to add a drug (not shown) to the excavated residual soil. As a structure of such a medicine addition part 23, the structure provided with the container 31 in which the medicine is accommodated as shown in FIG. 1, for example, and the connection pipe 32 which connects the container 31 and the introduction part 21 is mentioned. However, it is not particularly limited. Further, the drug addition unit 23 may be installed after the crushing unit 22.

  The container 31 contains a chemical capable of suppressing elution of arsenic existing in the excavated residual soil from the excavated residual soil. In this embodiment, polyaluminum chloride (PAC) is used as such a drug. PAC is less susceptible to changes in pH and external environmental changes such as in seawater, and stably exhibits the effect of suppressing arsenic elution from excavated soil. Therefore, it becomes possible to bury the excavated residual soil after the arsenic insolubilizing treatment, for example, in the ocean, and the selection range of the post-treatment method of the excavated residual soil is expanded. PAC is also used at construction sites for purposes other than insolubilization of arsenic, and is an inexpensive substance that is widely spread and easily available. Therefore, by using PAC as a chemical, arsenic insolubilization processing from excavated residual soil in this embodiment is economically performed.

  The chemical is added from the chemical addition unit 23 to the excavation residual soil introduced into the introduction unit 21. It is preferable that the amount of the chemical added is appropriately set so that the amount of arsenic eluted from the excavated residual soil is sufficiently suppressed below the threshold value. For example, if the threshold is 0.01 [mg / L], which is the elution standard of the Soil Contamination Countermeasures Law, for example, 0.4% by weight or more with respect to the excavated residual soil with an elution amount of 0.1 [mg / L] The amount of elution that is less than the above threshold is realized.

  FIG. 2 is a horizontal sectional view showing the crushing portion 22. On the upper surface of the crushing portion 22, the other end portion 21 b of the introducing portion 21 is opened. However, illustration of the upper surface of the crushing part 22, the introduction part 21, and the connecting pipe 32 is omitted in FIG. 3 and FIG. 4 are longitudinal sectional views showing the crushing portion 22, FIG. 3 is a view corresponding to a view taken along the line XX shown in FIG. 2, and FIG. 4 is a Y- It is a figure corresponding to the case where an arrow is seen by a Y line.

As shown in FIGS. 2 to 4, the crushing portion 22 includes a container 35 and three shaft blades (rotating blades) 36 </ b> A, 36 </ b> B, and 36 </ b> C.
The container 35 is a casing of the crushing unit 22, includes an introduction hole 37 and a lead-out hole 38, and includes a crushing / mixing stirring unit 40 and a filter 47 in the same space. An introduction hole 37 is provided in the upper part of the container 35, and excavation residual soil and chemicals can be introduced from the introduction part 21 through the introduction hole 37 in the direction of the arrow D <b> 2. A lead-out hole 38 is provided in the lower part of the container 35, and the excavated residual soil that is crushed inside the container 35 and mixed and stirred with the chemical can be led out in the direction of arrow D 3 through the lead-out port 42. The container 35 is formed in a substantially cylindrical shape, for example.

  The crushing / mixing stirring unit 40 is a place for crushing the excavated soil and mixing it with the chemicals, and stirring them. Shaft blades 36 </ b> A, 36 </ b> B, and 36 </ b> C are disposed in the crushing / mixing stirring unit 40. Each of the shaft blades 36 </ b> A, 36 </ b> B, 36 </ b> C has a rotary shaft 45 provided along the longitudinal direction of the crushing / mixing stirring unit 40 and a blade 46 attached to the rotary shaft 45.

The rotating shaft 45 is a member that rotates the blade 46 about itself by being rotated by a motor (not shown) or the like. That is, the center of the rotation shaft 45 constitutes the axis of rotation of the blade 46.
The base end portion of the blade 46 is connected to the rotation shaft 45. The blade 46 extends toward the inner peripheral surface of the container 35. Although the blade 46 formed in the rod shape is illustrated in FIGS. 2 to 4, the shape of the blade 46 and the number attached to the rotating shaft 45 are not particularly limited. The blade 46 may be formed in a plate shape such as a rectangle or a saw shape. The blade 46 may be mounted continuously or intermittently so as to draw a spiral with respect to the rotating shaft 45.

As shown in FIG. 2, the rotation shafts 45 of the three shaft blades 36 </ b> A, 36 </ b> B, 36 </ b> C are arranged such that their centers are located at the corners of the regular triangle T when viewed from above. The length of one side of the equilateral triangle T is appropriately longer than the length of the blade 46, and is set so that the size of the lap zone L can be sufficiently secured when the three shaft blades 36A, 36B, 36C are rotated. . Further, when viewed from the top, the blade 46 is arranged to extend in four directions from the center of the rotation shaft 45, and when viewed from the side as shown in FIGS. Connected and supported at three locations in the direction. In such an arrangement, the blade 46 is mounted on the rotary shaft 45 when the rotary shafts 45 of the three shaft blades 36A, 36B, and 36C are rotated in the directions of arrows D4, D5, and D6 shown in FIG. The blades 46 of the three shaft blades 36A, 36B, and 36C can be formed so that the blades 46 pass through each other without contact between the blades 46.
The number and arrangement of the blades 46 are not particularly limited, and are set so that stirring can be performed by cutting a space forming the crushing / mixing stirring unit 40.

  Accordingly, the excavated residual soil introduced into the crushing / mixing agitation unit 40 from the introduction hole 37 is struck by the plurality of blades 46 by the rotation of the three shaft blades 36A, 36B, 36C, as illustrated by the arrow D7. Played in every direction. The excavated residual soil that has been bounced off repeats countless collisions within the lap zone L, and is crushed instantaneously to become fine particles. In this embodiment, the excavation residual soil is mud. Furthermore, it is agitated with the drug and mixed and stirred well.

  The filter 47 is a member having a large number of pores (not shown) provided between the crushing / mixing stirring section 40 and the outlet hole 38. The excavated residual soil that has been crushed and mixed and stirred with the chemicals passes through the pores of the filter 47, is guided in the direction of arrow D <b> 3, and is derived from the outlet hole 38.

  As shown in FIG. 1, the derivation unit 25 derives the excavated residual soil crushed by the crushing unit 22 and mixed and stirred with the chemicals to the outside of the excavated residual soil treatment system 1, that is, in the present embodiment, to the second soil discharging unit 54. It is configured to be possible. The derivation unit 25 is constituted by, for example, a pipe or the like, and one end portion 25a of the derivation unit 25 opens at a lower portion of the crushing unit 22 of the excavation residual soil treatment mechanism 30 and is connected to the derivation hole 38. The end portion 25 b is connected to one end portion 66 a of the screw conveyor 66. A valve 26 is provided at one end portion 25a of the derivation unit 25. The valve 26 is capable of adjusting the timing at which the excavated residual soil is derived or the amount of excavated residual soil.

The second soil discharging unit 54 is configured to be able to discharge the excavated residual soil discharged from the derivation unit 25 of the excavated residual soil processing system 1 outward, and includes a screw conveyor 66. One end portion 66 a of the screw conveyor 66 is connected to the other end portion 25 b of the lead-out portion 25 of the excavation residual soil processing system 1. The other end (not shown) of the screw conveyor 66 is connected to an external conveyor (not shown) opened to the outside of the shield excavator 20 (for example, the ground).
Therefore, the excavated residual soil derived from the excavated residual soil processing system 1 is introduced into the screw conveyor 66, conveyed by the screw conveyor 66 in the direction of arrow D1, and then discharged to the ground or the like.
The configuration of the second earth removing unit 54 is not particularly limited as long as the excavated residual soil can be excavated at least outside the excavated residual soil treatment system 1 such as the ground, and similarly to the first earth discharging unit 52, For example, it may be composed of a transport pipe made of metal or resin, and excavation residual soil transport means attached to the transport pipe.

As described above, the excavated residual soil treatment system 1 according to the present embodiment includes the excavated residual soil treatment mechanism 30 configured to crush the excavated residual soil generated when excavating the soil layer and to add chemicals to the excavated residual soil. ing.
According to the above configuration, when the excavated residual soil is introduced into the excavated residual soil processing mechanism 30, the excavated residual soil is reliably crushed and becomes finely granular. Further, by adding a chemical such as PAC to the excavated residual soil, the chemical penetrates evenly into the excavated residual soil, and the chemical reaction between the excavated residual soil and the chemical is reliably and efficiently promoted. Therefore, the arsenic elution suppression effect in the excavation residual soil by the chemical can be sufficiently exerted, and the arsenic elution amount from the excavation residual soil existing in the excavation residual soil can be suppressed to a threshold value or less.

In the excavation residue processing system 1 of the present embodiment, the excavation residue treatment mechanism 30 includes an introduction unit 21 for introducing excavation residue, a chemical addition unit 23 for adding a chemical to the excavation residue, and excavation residue introduced from the introduction unit 21. A crushing unit 22 for crushing and a deriving unit 25 for deriving excavated residual soil are provided. Moreover, in the excavation residual soil processing system 1 of this embodiment, the crushing part 22 is equipped with the structure which can mix and stir excavation residual soil and a chemical | medical agent.
According to the said structure, excavation residual soil is introduce | transduced into the crushing part 22 via the introducing | transducing part 21, and is crushed, and becomes a granular form. Moreover, a chemical | medical agent is added to excavation residual soil from the chemical | medical agent addition part 23, and the finely excavated residual soil and chemical | medical agent are mixed and stirred. The agitated excavated soil is led out from the crushing unit 22 and further led out from the crushing unit 25 toward the outside of the excavated residue soil processing system 1. By such a smooth treatment, the chemical can be evenly penetrated into the excavated residual soil, and the chemical reaction between the excavated residual soil and the chemical can be promoted reliably and more efficiently.

Moreover, in the excavation residual soil processing system 1 of this embodiment, the chemical | medical agent addition part 23 is installed in the part before excavation residual soil passes through the crushing part 22, or the part after excavation residual soil passes through the crushing part 22. It is characterized by being. In the present embodiment, the chemical addition unit 23 is installed in a portion before the excavated residual soil passes through the crushing unit 22, that is, connected to the introduction unit 21.
According to the said structure, the excavation residual soil to which the chemical | medical agent was added previously is crushed by the crushing part 22, and it becomes a granular shape, and excavation residual soil and a chemical | medical agent are knead | mixed and stirred, and a chemical | medical agent osmose | permeates equally to the inside of excavation residual soil. On the other hand, if the chemical addition unit 23 is installed in a portion after the excavation residual soil has passed through the crushing portion 22, the chemical is added to the excavation residual soil finely divided by the crushing portion 22, and the chemical is evenly distributed to the inside of the excavation residual soil. To penetrate. Even if the chemical addition unit 23 is installed in any part, the chemical reaction between the excavation residual soil and the chemical can be promoted reliably and more efficiently.

The shield excavator 20 according to the present embodiment includes the excavation residual soil processing system 1.
According to the above configuration, the excavated residual soil generated in the shield excavator 20 is introduced into the excavated residual soil treatment system 1, so that the excavated residual soil is reliably crushed into a fine granular shape, and a chemical such as PAC is contained inside the excavated residual soil. The chemical reaction between the excavated soil and the chemical is reliably and efficiently promoted.

The shield excavator 20 according to the present embodiment includes an excavation mechanism 50 that excavates a soil layer, a first earth discharge unit 52 that excavates residual excavation generated by the excavation mechanism 50 toward the excavation residual soil treatment system 1, and excavation residual soil. And a second earth removing portion 54 for discharging the excavated residual soil derived from the processing system 1 to the outside.
According to the above configuration, the excavation residual soil generated by excavation of the soil layer using the excavation mechanism 50 is discharged to the excavation residual soil treatment system 1 by the first earth discharge unit 52 and introduced into the excavation residual soil treatment system 1 and processed. Is done. That is, the excavated residual soil is reliably crushed into fine particles, and a chemical such as PAC is added to the excavated residual soil, and these are mixed and stirred. The treated excavation remaining soil is discharged out of the shield excavator 20 by the second soil discharging unit 54. By such a smooth treatment, the chemical can penetrate evenly into the excavated residual soil, and the chemical reaction between the excavated residual soil and the chemical can be promoted reliably and more efficiently.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. It can be changed.

For example, the material to be treated present in the excavated residual soil is not limited to arsenic. And the chemical | medical agent added to excavation residual soil is not limited to PAC, What is necessary is just the chemical | medical agent which can suppress the elution from the excavation residual soil of the process target substance which exists in excavation residual soil below a threshold value.
Moreover, in the said embodiment, the one end part 32b of the connection pipe 32 of the chemical | medical agent addition part 23 is connected with the introducing | transducing part 21 of the excavation residual soil processing system 1 (refer FIG. 1). In addition, it is only necessary to be able to add to the excavation residual soil before stirring or at the time of mixing and stirring, and the one end portion 32b of the connection pipe 32 may be connected to any position. For example, the one end portion 32 b of the connection pipe 32 may be connected to the screw conveyors 60, 62, 64 constituting the first soil discharge portion 52, or the upper portion of the container 35 of the crushing portion 22 of the excavation residual soil treatment system 1. Thus, since the freedom degree of the installation place of the chemical | medical agent addition part 23 is large, the freedom degree of design of the excavation residual soil processing system 1 and the shield excavator 20 also becomes large.

  In the above embodiment, the excavation residual soil is crushed and the excavation residual soil treatment system 1 including the crushing portion 22 capable of mixing and stirring the excavation residual soil and the chemical has been described. What is necessary is just to be comprised so that crushing remains of excavation can be crushed. As a mechanism of such a crushing unit 22, for example, a uniaxial crusher that crushes excavated residual soil by a shearing force acting between a rotary blade having a plurality of blades attached to a rotary shaft and a fixed blade, and two arranged adjacent to each other. A biaxial crusher that crushes excavated surplus soil with a large shearing force acting between the rotary blades by rotating two rotary blades inside each other, a hammer-type crusher that crushes excavated surplus soil by hitting it with a hammer at high speed, a hydraulic motor A bucket crusher that crushes the excavated residual soil with a bucket having two jaws is available, but the excavated residual soil is not particularly limited as long as the excavated residual soil can be crushed to such a degree that the effect of mixing the chemicals is exhibited.

  Next, examples carried out in order to support the effect of the excavation residual soil treatment system 1 according to the embodiment of the present invention described above will be described. In addition, this invention is not limited only to a following example.

  A multi-crusher BIG BANG (manufacturer: Fuji machine Co., Ltd.) was prepared as the crushing section 22 having the configuration shown in FIGS. Furthermore, two screw conveyors 64 and 66 were prepared as the first earth discharging part 52 and the second earth discharging part 54. The other end 64b of the screw conveyor 64 was connected to the multi-crusher inlet, and one end 66a of the screw conveyor 66 was connected to the multi-crusher outlet. The earth and sand excavated from the natural ground as the excavated residual soil was introduced into one end portion 64a of the screw conveyor 64, and introduced into the crusher from the multi-crusher inlet. In addition, 0.5 to 1.0% by weight of PAC was added as a chemical to the earth and sand.

  Next, the three shaft blades of the multi-crusher were operated at 840 revolutions per minute until the sediment became fine, and the sediment was crushed and the sediment and the chemical were mixed and stirred. Thereafter, the earth and sand were led out to the screw conveyor 66 from the outlet of the multi-crusher and taken out from the screw conveyor 66. The amount of arsenic eluted from the earth and sand and the pH were measured using an ICP emission spectroscopic analyzer (distributor: Seiko Instruments Inc.) and a pH measuring electrode (distributor: Horiba, Ltd.), respectively.

  The measurement results of the amount of arsenic eluted from the earth and sand are shown in FIG. In FIG. 5, “before treatment” indicates the initial elution concentration of arsenic before adding the drug, and “after process” indicates the arsenic elution concentration after the drug addition process. Also, in the “addition position” in the figure, “Previous” indicates that PAC was added to the soil before crushing with the multi-crusher, and “After” indicates that PAC was added to the soil after crushing with the multi-crusher. Is shown.

  As shown in FIG. 5, since the chemical is not added to the excavated residual soil in “Before treatment”, the amount of arsenic eluted from the excavated residual soil exceeds 0.01 [mg / L], which is the elution standard of the soil pollution countermeasure method. ing. On the other hand, in the “after treatment”, after adding PAC to the earth and sand, the earth and sand are crushed with a multi-crusher and the earth and sand and PAC are stirred, so that the amount of arsenic eluted from the earth and sand is 0.01 [mg / mg]. L] The following was confirmed and the effect of the present invention was confirmed. When PAC was added by 0.5% by weight of earth and sand, and when 0.75% by weight was added, the amount of arsenic eluted from the earth and sand was 0 [mg / L]. Further, even when 1.0% by weight of PAC was added to the earth and sand, the amount of arsenic eluted from the earth and sand was reduced to about 0.002 [mg / L].

In addition, for example, when PAC is introduced together with excavated earth and sand from one end 64a of the screw conveyor 64, PAC is added to finely divided earth and sand after being crushed by a multi-crusher, so that arsenic is eluted from the earth and sand. The amount was 0.01 [mg / L] or less, and the effect of the present invention was obtained. When PAC was added at 0.5% by weight of the earth and sand and 1.0% by weight, the elution amount of arsenic from the earth and sand was 0 [mg / L]. Further, when PAC was added at 0.75% by weight of the earth and sand, the amount of arsenic eluted from the earth and sand was reduced to less than 0.002 [mg / L]. That is, it is considered that the arsenic elution suppression effect of the excavation residual soil by the chemical agent was efficiently and surely exerted by adding a predetermined amount of PAC to the crushed earth and sand regardless of the addition position of PAC.
As described above, according to the excavation residual soil treatment system to which the present invention is applied, the chemical can be uniformly permeated into the excavation residual soil, so that the chemical reaction between the excavation residual soil and the chemical is efficiently promoted, and the chemical It was confirmed that the arsenic elution suppression effect in the excavated residual soil was fully exhibited.

DESCRIPTION OF SYMBOLS 1 Excavation residual soil processing system 20 Shield excavator 21 Introduction part 22 Crushing part 23 Drug addition part 25 Derivation part 30 Excavation residual soil processing mechanism 50 Excavation mechanism 52 First earth removal part 54 Second earth removal part

Claims (5)

  An excavation residual soil treatment system comprising a excavation residual soil treatment mechanism configured to crush the excavation residual soil generated when excavating the soil layer and to add a chemical to the excavation residual soil. The excavation residue processing mechanism is
An introduction part for introducing the excavated residual soil;
A drug addition unit for adding the drug to the excavated soil;
A crushing unit for crushing the excavated residual soil introduced from the introduction unit;
The excavation residual soil processing system according to claim 1, further comprising a derivation unit that derives the excavation residual soil. The drug addition part is
The excavation residual soil processing system according to claim 2, wherein the excavation residual soil treatment system is installed in a portion before the excavation residual soil passes through the crushing portion or a portion after the excavation residual soil passes through the crushing portion.   The shield excavator provided with the excavation residual soil processing system as described in any one of Claims 1-3. An excavation mechanism for excavating the soil layer;
A first excavation portion for excavating residual excavation generated by the excavation mechanism toward the excavation residual soil treatment system;
The shield excavator according to claim 4, further comprising: a second earth discharging unit that discharges the excavated residual soil derived from the excavated residual soil processing system outward.

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