JP6415897B2 - Ground improvement method - Google Patents

Description

The present invention relates to a ground improvement technique for cutting a soil (in-situ soil) in the ground to be improved, mixing and stirring water and a solidifying material (for example, cement), and creating a ground consolidated body.

A drilling hole is drilled in the ground to be improved, an injection device is inserted into the drilling hole, and a high-pressure fluid (for example, water) is sprayed radially outward from the injection device while cutting the soil, and the injection device Rotate and move vertically (pick up or push down), and mix and agitate the in-situ soil and the solidified material by jetting or discharging a solidified material such as cement, for example. A technique for creating a ground solid consolidated body having a rotating body shape is widely known (see, for example, Patent Document 1).
In order to improve the strength (quality) of the formed underground solid body, the ratio W / C between the supplied solidifying material (cement) and water is low, and so-called “rich blending” is desirable.

However, if W / C is low, the viscosity of the mixture of cement and water increases, which may block the conveyance path from the cement supply source to the injection device, and convey the solidified material to the injection device. Is difficult.
Further, not all of the solidified material injected from the injection device is solidified in the ground, but a large amount of solidified material is discharged to the ground side as slurry. Therefore, in reality, there are a large amount of solidified materials that are disposed of as industrial waste. When the W / C is low and so-called “rich blending”, the amount of the solidified material that is disposed of increases, and the construction cost increases accordingly.
For the reasons described above, in the prior art, a so-called “poor blended” solidified material having a W / C of 100% or more has to be used.

Japanese Patent Laid-Open No. 7-331652

The present invention has been proposed in view of the above-mentioned problems of the prior art, and is formed into a so-called “rich blend” by reducing the ratio W / C of the solidified material (cement) and water. The strength or quality of the consolidated body can be improved, the solidified material can be reliably conveyed from the supply source to the injection device, and the amount of the solidified material processed as industrial waste can be reduced. The purpose is to provide a ground improvement method.

The ground improvement method of the present invention includes a step of drilling a digging hole (H) in the ground (G) to be improved, an injection device (1) inserted into the digging hole (H), and a ground ( G) a step of rotating (injecting) the injection device (1) in a vertical direction while injecting a fluid (stable liquid, partition forming material) for cutting, and a step of injecting a solidified material from the injection device (1). Have
The step of rotating (injecting) the injection device (1) in the vertical direction while injecting the fluid (stable liquid, partition formation material) for cutting the ground (G) from the injection device (1) is performed by the partition formation material. And a step of cutting the ground (G) and a step of spraying the solidified material (C) while cutting the ground (G) by spraying the stabilizing liquid after spraying the partition forming material. It is characterized by.

In the present invention, the step of collecting the mixture of the stable liquid discharged to the ground side and the cut soil (S: slurry) by the slurry collecting mechanism (2),
A step of transporting the slurry (S) recovered by the slurry recovery mechanism (2) to the slurry processing mechanism (4) and adding an enzyme (E: cellulolytic enzyme such as cellulase) from the enzyme supply source (5); Is preferred.

The ground improvement method of the present invention is also a contaminated water purification method, a step of drilling a drilling hole (H) in the ground (G) to be improved, and an injection device (1) inserted into the drilling hole (H) for injection. A step of rotating (or turning) the injection device (1) in a vertical direction while rotating or rotating the injection device (1) while injecting a fluid (stable liquid, partition forming material) for cutting the ground (G) from the device (1); The step of moving in the vertical direction while injecting is characterized in that zeolite is injected from the injection device (1).

According to the present invention having the above-described configuration, since the solidified material with a high blending ratio of water to cement (W / C) of 26% to 40% is used, the strength of the formed ground consolidated body is increased. (Quality) can be improved as compared with the strength of the underground consolidated body formed by a conventional poorly-solidified solidifying material.
Here, the solidifying material (solidifying material rich in W / C of 26% to 40%) includes a high fluidizing agent, and even when rich, the increase in viscosity of the solidifying material is suppressed. . Therefore, according to the present invention, it is possible to transport the rich blended solidified material by the solidified material transport pump used in the prior art, that is, the poor blended solidified material transport pump.

In the present invention, prior to the step of cutting the soil with the stabilizing liquid, if the partition forming material is sprayed, a layer (L _W ) of the mixture of the stabilizing liquid and the cut soil (L _W ) and a layer of the solidified material of the rich blend ( L _C ), a separation layer (L _D ) composed of a partition forming material is formed.
Such a separation layer (L _D : a layer composed of a partition forming material) suppresses the contact of the rich blended solid material injected into the ground with the mixture of the stabilizing liquid and the cut soil.
Therefore, only the mixture of the stabilizing liquid and the cut soil is discharged as slurry (S) to the ground side, and the solidified material with rich blend is hardly discharged to the ground side. That is, the layer of the partition-forming _material: the (L D separating layer), it is possible to suppress the solidification agent injected into the ground from being discharged to the ground side.
Since the solidified material is suppressed from being discharged to the ground side as the slurry (S), according to the present invention, the amount of the solidified material discharged to the ground side as the slurry (S) as compared with the prior art. The construction cost is saved by that amount.

In this invention, it has the process of collect | recovering the mixture (S: slurry) of the stable liquid discharged | emitted on the ground side, and the cut | disconnected soil by a slurry collection | recovery mechanism (2), The slurry (S) spouted to the ground side Can be recovered. Therefore, it is possible to prevent the slurry (S) from being scattered around the construction site and deteriorating the working environment.
In addition, a step of transporting the slurry (S) recovered by the slurry recovery mechanism (2) to the slurry processing mechanism (4) and adding an enzyme (E: cellulolytic enzyme such as cellulase) from the enzyme supply source (5). By having the slurry (S), which is a mixed solution of the stabilizing solution and the cut soil, the guar gum (natural water-soluble polymer material) in the stabilizing solution is decomposed by the cellulose-degrading enzyme (E), and water and soil Only mixed solution. Here, since it is not necessary to process as industrial waste if it is a liquid mixture of only water and soil, unlike the prior art, it is not necessary to send the slurry as industrial waste to a treatment facility.

In the present invention, the spraying device (1) is rotated or rotated to move (pull up) while spraying the fluid (stable liquid, partition forming material) for cutting the ground (G) from the spraying device (1). If zeolite is injected from the injection device (1) in the process, a zeolite layer (L _Z : zeolite bottom plate) can be formed in the ground.
It said zeolite deck slabs the (L _Z), for example in the ground near such reactor building (21), by arranging the outflow (leakage) pathway or diffusion paths of groundwater contaminated with radioactive materials (W _G), atomic Groundwater (W _G ) contaminated by radioactive material flowing out and diffusing from the reactor building (21) etc. into the ground flows into the zeolite bottom plate (L _Z ) in the process of flowing out and diffusing into the ground, and the zeolite bottom plate Pass (or pass) through (L _Z ).
In the process in which groundwater (W _G ) passes (permeates) through the zeolite bottom plate (L _Z ), most of the cesium occupying the radioactive material is adsorbed by the zeolite and removed from the groundwater. As a result, the concentration of radioactive material in the groundwater that has passed (permeated) through the zeolite bottom slab (L _Z ) is greatly reduced to a level below the so-called “reference value”. That is, the ground improvement method of the present invention also acts as a purification method for groundwater contaminated with radioactive substances.

It is explanatory drawing which shows embodiment of this invention. It is process drawing which shows the first process at the time of constructing embodiment. FIG. 3 is a process diagram showing a process that follows the process shown in FIG. 2. It is an AA arrow directional cross-sectional view of the injection apparatus shown in FIG. FIG. 4 is a process diagram showing a process that follows the process shown in FIG. 3. FIG. 6 is a process diagram showing a process that follows the process shown in FIG. 5. It is a flowchart which shows the procedure of FIGS. It is a figure explaining the problem which should be solved by other embodiment of this invention. It is explanatory drawing which shows other embodiment of this invention. It is process drawing which shows the process of other embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, equipment necessary for constructing the ground improvement method according to the embodiment will be described with reference to FIG.
In FIG. 1, the ground on which the construction method of the present invention is applied is indicated by the symbol G. The rod-shaped injection device 1 is inserted into the excavation hole H drilled in the ground G.
Here, the erection mechanism 6 indicated by a dotted line in FIG. 1 is a device for inserting (building) the injection device 1 into the excavation hole H.

Although not shown in FIG. 1, the injection device 1 has a double tube structure (see FIG. 4). In FIG. 4, the inner space of the inner tube 15 constitutes a flow path through which a rich blended solidifying material is supplied. An annular space between the inner tube 15 and the outer tube 16 constitutes a flow path to which a stabilizing liquid or a partition forming material is supplied.
In FIG. 1, a solidifying material discharge port 11 (jet port) is provided at the lower end of the spray device 1. A plurality (two in FIG. 1) of injection ports 12 (for example, nozzles) are provided at a position vertically above the lower end of the injection device 1.
In the horizontal cross section of the injection device 1, the plurality of injection ports 12 (two in FIG. 1) are arranged so as to be symmetric with respect to a vertical central axis (not shown). The plurality of injection ports 12 are provided for injecting the stabilizing liquid or the partition forming material.

The stabilizing liquid and the partition forming material are not simultaneously ejected from the plurality of ejection ports 12. As will be described later with reference to FIGS. 5 and 6, a partition forming material is injected from the injection port 12 prior to the step of cutting the soil by injection of the stabilizing liquid from the plurality of injection ports 12.
As shown in Figure 1, a layer L _W of a mixture of which is cut a stable liquid soil, between the layer L _C of the solidifying material (consolidated material wealth formulation), and soil which has been cut with the partition forming material separation layer L _D composed of a mixture is formed.
In Figure 1, after the step of forming a separation layer L _D by injecting the partition-forming material, and the separation layer L _D constituted by the partition-forming material is formed, from the injection port 12 is the jet J of stabilizer The state of being sprayed and cutting the soil is shown. Here and solidified material is discharged (injected) from the injection device 1 the lower end of the discharge port 11, and forms a layer L _C of solidifying material.

In the illustrated embodiment, a solution containing 5% by weight of a thickening agent (for example, guar gum, which is a natural water-soluble polymer material) is sprayed from the spray ports 12 of the spray device 1 as a stabilizing liquid to excavate the soil. ing.
In the illustrated embodiment, the partition forming material is a solution containing 5% by weight of a thickener (eg, guar gum which is a natural water-soluble polymer material) and 5% by weight of sodium silicate (water glass). Then, by mixing with the local soil by a partition-forming material is injected into the soil to form a separation tank L _D.
In the illustrated embodiment, the solidifying material is a mixture of rich cement and water, for example, a mixture having a W / C of 26% to 40%. Note that W / C = 26% is a theoretical value, and W / C cannot be made lower than this. On the other hand, in the inventor's experiment, when W / C exceeded 40%, the desired strength (quality) could not be obtained in the underground consolidated body.

In the illustrated embodiment, a superplasticizer is added to the solidifying material (W / C is 26% to 40%). By adding a high fluidizing agent, an increase in the viscosity of the solidified material rich in W / C of 26% to 40% is suppressed, and the solidified material of rich blend (W / C is 26% to 40%). % Solidified material) can be transported by a pump for transporting a poorly blended solidified material (ordinary solidifying material transport pump).
In the illustrated embodiment, as the superplasticizer, a polycarboxylic acid compound (for example, “Tupol”, a product name of Takemoto Yushi Co., Ltd.) is added in an amount of 3 to 7% by weight based on the cement. In the experiments by the inventors, the case where the polycarboxylic acid compound was added by 5% by weight with respect to the cement was suitable for transporting the solidified solidified material.
In the inventor's experiment, a mixture (mixed solidified material) obtained by mixing and stirring 100 parts by weight of cement, 25 parts by weight of water, and 5 parts by weight of a polycarboxylic acid compound is a normal solidified material transporting pump, that is, a poorly mixed material. The solidified material (W / C was 100% or more) could be transported by a pump used for transporting the solidified material.

In FIG. 1, the injection device 1 communicates with a partition forming material supply source 7 via an introduction part 14 and a supply line 17, and communicates with a stable liquid supply source 8 via an introduction part 14 and a supply line 18. Yes. Furthermore, the injection device 1 communicates with the solidification material supply source 9 via the introduction part 13 and the supply line 19.
The supply lines 17, 18 and 19 are provided with a switching valve 10. By switching the switching valve 10, each of the partition forming material, the stabilizing liquid, and the solidifying material is supplied to the injection device 1 or stopped.

In the state shown in FIG. 1, the formation of the isolation layer L _D is completed, the cutting soil by injecting stabilizing solution, ejected to form a layer L _C of (injection) solidified material has solidified material . Therefore, in FIG. 1, the switching valve 10 blocks the supply of the partition forming material from the partition forming material supply source 7 to the injection device 1, but supplies the stabilizing liquid from the stable liquid supply source 8 to the injection device 1, and solidifies the material. The switching position is to supply the solidified material from the supply source 9 to the injection device 1.
Instead of the switching valve 10, the pump of the partition forming material supply source 7 (not shown), the pump of the stabilizing liquid supply source 8 (not shown), and the pump of the solidifying material supply source 9 (not shown) are turned on. With the OFF control, it is possible to control the supply / stop of supply of the partition forming material, the stabilizing liquid, and the solidifying material.

As described above, when the injection device is rotated while jetting high-pressure water and solidified material from the injection device (and thus the injection direction of the injection nozzle is rotated) and moved in the vertical direction (for example, pulled up), the conventional ground improvement In the construction method, the solidified material flows back to the ground side and is discharged as a slurry that is a mixture of water, soil, and solidified material.
On the other hand, in the illustrated embodiment, as shown in FIG. 1, the layer L _D (separation layer) of the mixture of the partition forming material and the cut soil is a layer of the mixture of the stable liquid and the cut soil. and L _W, are partitioned from the layer L _C of solidifying material wealth formulation. Therefore, a layer L of a stabilizing solution that cutting soil layer L _C of solidifying material wealth formulation, rarely resulting in mixed beyond the separation layer L _D.

Solidifying material wealth formulation is injected, as the vertical dimension of the solidifying material layer L _C increases (becomes thicker) layers L _{D (separation} layer) of the partition-forming material is moved upwardly.
As a result, the mixture of which is cutting the stabilizer soil is discharged to the ground side (as a slurry), it is consolidated material in the solidifying material layer L _C is discharged to the ground side beyond the separation layer L _D Suppressed or prevented.
In other words, in the illustrated embodiment, the solidified material (rich blended solidified material) discharged (injected) into the soil is discharged to the ground side by the partition forming material layer L _D (separated layer). Is suppressed. Therefore, in the illustrated embodiment, the slurry discharged (reversely flowing) to the ground side includes the stabilizing liquid and the cut soil, but the solidified material is prevented from being discharged to the ground side as a slurry. It is.

Here, the thickness dimension of the layer L _D (separation layer) of the partition forming material is such that the solidifying material discharge port 11 (discharge port at the lower end of the injection device 1) and the injection port from which the stable liquid or the partition forming material is discharged. 12 is equal to a vertical distance L with respect to 12 (a plurality of injection ports provided above the discharge port 11).
Then, the vertical distance L between the discharge port 11 and the injection port 12, the separation layer L _D constituted by the partition-forming material is solidified layer L _W and wealth formulation of a mixture of which is cut a stable liquid soil partition and a layer L _C of wood, is set to solidification material thickness required to prevent the mixing with the mixture of soil that has been cut with the stabilizing solution wealth formulation (vertical dimension).
In the illustrated embodiment, the thickness dimension (vertical distance) L is set to 1 m.

A slurry recovery mechanism 2 is provided on the ground surface portion of the excavation hole H.
In FIG. 1, the slurry is ejected to the ground side through an annular space between the inner wall surface of the excavation hole H and the injection device 1.
In FIG. 1, the slurry discharged to the ground side is recovered by the slurry recovery mechanism 2. Therefore, the situation where the slurry is scattered around the construction site and the working environment is deteriorated is prevented.
A known technique may be applied to the slurry collecting mechanism 2.

The slurry recovered by the slurry recovery mechanism 2 is sent to the slurry processing mechanism 4 via the slurry conveyance line 3. An enzyme (cellulolytic enzyme such as cellulase) is added from the enzyme supply source 5 to the slurry sent to the slurry processing mechanism 4.
Here, in the prior art, since the slurry discharged to the ground side includes the solidified material, it must be treated as industrial waste. However, in FIG. 1, as described above, the slurry sent to the slurry processing mechanism 4 is a mixed solution of the stabilizing liquid and the cut soil, and inclusion of the solidified material is suppressed. Therefore, in FIG. 1, when cellulose-degrading enzyme is added to the slurry sent to the slurry processing mechanism 4, guar gum (natural water-soluble polymer material) in the stable liquid is decomposed by the cellulose-degrading enzyme. It becomes a mixed solution. If it is a mixture of water and soil only, it does not fall under industrial waste, and there is no need to transport it to a treatment facility as industrial waste.

Next, with reference to FIGS. 2-7, the construction procedure of the ground improvement construction method mentioned above is demonstrated.
FIG. 2 shows a state where the excavation hole H is drilled in the ground G to be improved. The injection device 1 is inserted into the excavation hole H.
2, the inner diameter D _H of the borehole H is larger than the outer diameter of the injector 1 to be inserted. Here, when the soil of the ground G is cut with the stabilizing liquid, the slurry is discharged to the ground side through an annular space between the inner wall surface of the excavation hole H and the outer peripheral surface of the injection device 1 ( backflow) is, the inner diameter D _H of the borehole H is set to a value which the slurry is smoothly discharged to the ground side.
The depth L _H borehole H is set according to the depth of the soil to be ground improvement.

In FIG. 3 showing a step subsequent to the step shown in FIG. 2, the rod-shaped injection device 1 is inserted into the excavation hole H. When the injection device 1 is inserted, a known built-in mechanism 6 is used.
FIG. 4, which is a cross-sectional view taken along the line AA in the vicinity of the injection port 12 of the injection device 1 in FIG. 3, shows only the injection device 1 and does not show the cross section of the excavation hole H. As shown in FIG. 4, the injection device 1 has a double tube structure with the inner tube 15 and the outer tube 16, and the solidified material flows through the inner tube 15, and the inner tube 15 and the outer tube 16. Stabilizing liquid or partition forming material flows through the space between them.
Note that the stabilizing liquid and the partition forming material are not sprayed at the same time. Only one of them is injected depending on the process. The stabilizing liquid and the partition forming material introducing portion 14 are connected to the plurality of injection ports 12 through an annular space (see FIG. 4) between the inner tube 15 and the outer tube 16 of the injection device 1 and a pipe (not shown). Communicate.

FIG. 3 shows a state in which the injection device 1 is inserted into the excavation hole H. In the state of FIG. 3, none of the solidifying material, the stabilizing liquid, and the partition forming material is injected or discharged into the soil.
Although not clearly shown, simultaneously with the injection of the stabilizing liquid and the partition forming material, the injection device 1 is rotated around the central axis in the longitudinal direction and pulled up. Is provided.
In FIG. 3, the slurry recovery mechanism 2 provided on the ground surface portion of the excavation hole H communicates with the annular space between the inner wall surface of the excavation hole H and the outer peripheral surface of the injection device 1, and the slurry ejected to the ground side Is recovered. The slurry recovery mechanism 2 is operated by a power mechanism (not shown).

FIG. 5 is a process diagram for cutting the ground G by injecting a partition forming material in a process subsequent to the process shown in FIG. 3. 5 and 6, the illustration of the erection mechanism 6 is omitted.
In FIG. 5, the partition forming material is introduced into the injection device 1 from the introduction portion 14 through the supply line 17 and the switching valve 10 from the partition forming material supply source 7, and an annular shape between the inner tube 15 and the outer tube 16. Through the space (see FIG. 4), the jets J are jetted radially outward from the plurality of jets 12 as jets J.
And the injection device 1 rotates the injection device 1 to move in the vertical direction (pulls up) while injecting the jet J of the partition forming material to cut the ground G. As a result, a layer L _D of a mixture of soil, which is cut a partition forming material (separation layer) is formed. As described with reference to FIG. 1, prior to the step of cutting the soil by injecting stabilizing solution, by forming a separation layer L _D constituted by the partition-forming material by injecting the partition-forming material, stabilized a layer L _W of a mixture of soil is cut with a liquid, without a layer L _C of the solidified material with each other intermingle, to maintain the separated state.

As shown in FIG. 5, in the process of cutting the ground G by injecting the partition forming material, the switching valve 10 opens only the supply line 17 from the partition forming material supply source 7 to the injection device 1, and the stable liquid supply source. 8 and the supply lines 18, 19 from the solidification source 9 to the injection device 1 are closed. Therefore, only the partition forming material is supplied to the injection device 1, and the stabilizing liquid and the solidified material are not supplied to the injection device 1.
Here, also in the process of cutting the ground G by injecting the partition forming material, slurry that is a mixture of the partition forming material and the cut soil is generated and flows back to the ground side. Slurry flowing back to the ground side is recovered by the slurry recovery mechanism 2.

The thickness dimension of the layer L _D (separation layer) of the partition forming material divides the predetermined dimension L (the layer L _W of the mixture of the stabilizing liquid and the cut soil and the layer L _C of the enriched solidified material, If the injection device 1 is pulled up to the thickness dimension necessary to prevent the solidified material of rich composition from mixing with the mixture of the stabilizer and the cut soil: 1 m in the illustrated embodiment) Then, the process shown in FIG. 5 is completed, and the process proceeds to the process shown in FIG.
In the process shown in FIG. 6, the solidified material is sprayed while spraying the stabilizing liquid and cutting the ground G. In the process shown in FIG. 6, the switching valve 10 shuts off the supply line L17 from the partition forming material supply source 7 to the injection device 1, but the supply line L18 from the stable liquid supply source 8 to the injection device 1 and the solidified material. The supply line L19 from the supply source 9 to the injection device 1 is opened.
As a result, the stabilizing liquid supplied from the stabilizing liquid supply source 8 via the supply line 18 and the switching valve 10 passes through the annular space between the inner pipe 15 and the outer pipe 16 from the upper introduction portion 14 of the injection device 1. Through (see FIG. 4), it is injected radially outward from the plurality of injection ports 12 into the ground. Then, the solidified material is introduced from the solidified material supply source 9 through the supply line 19 and the switching valve 10 from the solidified material introducing portion 13 at the top of the injection device 1 into the injection device 1, and the internal space of the inner pipe 15 (FIG. 4). And is discharged from the discharge port 11 into the ground.

The stabilizing liquid is injected as a jet J from the injection device 1 and cuts the ground G. And the injection device 1 is pulled up in the vertical direction while rotating.
On the other hand, the solidified material is discharged (injected) from the discharge port 11 provided at the lower end of the injection device 1. Then, the in-situ soil and the solidifying material are mixed to form an underground consolidated body.

A mixture of the stable liquid and the cut soil is obtained by injecting the stable liquid from the injection device 1 into the ground, cutting and stirring the ground G, and pulling up in the vertical direction while rotating about the axis of the injection device 1. Layer _LW is formed. Then, by discharging (jetting) the solidifying material in the ground from the injection device 1, the layers of solidifying material L _{C (ground} solid body) is formed.
As described above, between the layers L _W as the layer L _C of the solidified material mixture to have been cut with the stabilizing solution soil, since the separation layer L _D constituted by the partition-forming material is interposed, layer L _W of a mixture of which is cut a stable liquid soil and the layer L _C of the solidified material that is miscible is suppressed.

Solidifying material is discharged (injected) to continue from the injection device 1, the vertical dimension of the layer L _C of the solidified material is increased (thickened when), brought to it, the layer of the partition-forming material (isolation layer L _D) is upwardly Moving.
Therefore, the region above the isolation layer L _D composed of a partition-forming material, i.e. only from the layer L _W of a mixture of which is cut a stable liquid soil, slurry (a mixture of which is cut a stable liquid soil) is It is discharged to the ground side. Solidifying material wealth blended in the layer L _C of solidifying material can hardly be discharged to the ground side.

In the process shown in FIG. 6, since the solidified material is not discharged to the ground side, the slurry recovered by the slurry recovery mechanism 2 becomes a mixture of soil and water when enzymatically decomposed by the slurry processing mechanism 4. And if it is a mixture of soil and water, it is not necessary to treat it as industrial waste in a specialized treatment facility.
The process shown in FIG. 6 is continued until the solidified material layer L _C (underground consolidated body) reaches the vicinity of the ground and the vertical dimension of the underground consolidated body reaches a predetermined value.

FIG. 7 is a flowchart showing the procedure of the steps shown in FIGS.
The operation procedure of the illustrated embodiment will be described with reference mainly to the flowchart of FIG. 7 and also to FIGS.
In FIG. 7, in step S <b> 1, the switching valve 10 is switched to open only the supply line 17 from the partition forming material supply source 7 to the injection device 1, and the supply line 18 from the stable liquid supply source 8 and the solidification material supply source 9. The supply line 19 is closed and the partition forming material is supplied to the injection device 1. And while injecting the partition-forming material from the injection port 12 into the ground, pulling in the vertical direction by rotating the injector 1, hereinafter, to form the separation layer L _D constituted by the partition-forming material. Then, the process proceeds to step S2.

In step S2, the thickness is required thickness of the separation layer L _D constituted by the partition-forming material: determines whether the reached (vertical dimension L predetermined dimension). In other words, in step S2, it is determined whether or not the lifting amount of the injection device 1 is greater than or equal to the predetermined dimension L.
If raising the amount of the injector 1 (thickness of the separation layer L _D) is smaller than the thickness L required separation layer L _D returns to (Step S2 "NO") Step S1, the ground G by injecting partition forming material cutting the to continue the process of forming the separation layer L _D.
On the other hand, raising the amount of the injector 1 as long (separation layer thickness L _D) separation layer L _D required thickness L more (step S2 is "YES"), the process proceeds to step S3.

In step S 3, the switching valve 10 is switched to close the supply line 17 from the partition forming material supply source 7 to the injection device 1, and the supply line 18 from the stabilizing liquid supply source 8 to the injection device 1 and the solidification material supply source 9. The supply line 19 to the injection device 1 is opened. Thereby, injection of a partition formation material stops, a stable liquid is injected in a horizontal direction, and a solidification material is discharged.
And the injection device 1 is pulled up in the vertical direction while rotating while injecting the stabilizing liquid and cutting the ground G. At the same time, the solidified material is discharged (injected) from the discharge port 11 provided at the lower end of the injection device 1 and mixed with the cut in-situ soil to form an underground consolidated body.

The slurry (mixed fluid of the stabilizing liquid and the cut soil) generated in step S3 is recovered by the recovery mechanism 2 on the ground side, and is transported to the slurry processing mechanism 4 by the slurry transport line 3. Enzyme is added from the enzyme supply source 5 to obtain a mixed solution of only water and soil. Therefore, it is not necessary to transport it to a treatment facility as industrial waste.
Then, the process proceeds to step S4.

In step S4, the vertical dimension of the ground solid sintered layer L _C solidifying material reaches near the ground becomes a desired size, determines whether Construction of underground caking body has been completed.
If the solidified material layer L _C (underground consolidated body) does not reach the desired thickness and the formation of the underground consolidated body is not completed (step S4 is “NO”), step S3 is performed. The process of discharging (injecting) the solidified material while injecting the stabilizing liquid and cutting the ground G is continued.
Layer L _C of the solidified material becomes a desired vertical dimension, as long as the reclamation of ground consolidation body is completed (step S4 is "YES"), the process proceeds to step S5.

In step S5, the switching valve 10 is switched to close the supply line 18 from the stabilizing liquid supply source 8 to the injection device 1 and the supply line 19 from the solidifying material supply source 9 to the injection device 1, thereby stabilizing the liquid and the solidifying material. To the injection device 1 is stopped.
And the operation | movement which rotates the injection apparatus 1 and the operation | movement pulled up to the ground side at a predetermined speed are also stopped.
Since the passage from the partition forming material supply source 7 to the injection device 1 is closed in step S3, the partition formation material is not supplied to the injection device 1 also in step S5.
And the slurry collection | recovery mechanism 2, the slurry conveyance line 3, and the slurry processing mechanism 4 also stop, and it progresses to step S5 and complete | finishes an operation | work.

According to the illustrated embodiment, since the ratio of water to cement (W / C) is a solidified material (C) with a rich composition of 26% to 40%, the strength ( Quality) can be improved as compared with the case of a conventional solidified material with poor blending (W / C is 100% or more).
Here, since the solidifying material (C: solidified material having a high W / C content of 26% to 40%) contains a high fluidizing agent, an increase in the viscosity of the solidifying material (C) is suppressed. It can be transported using a normal solidifying material transport pump (pump for transporting poorly blended solidifying material in the prior art).

In the illustrated embodiment, prior to the step S3 of cutting the soil stabilizer, so it executes step S1 for forming an isolation layer L _D for injecting a partition-forming material composed of a partition forming material, separating layer L a layer L _W of a mixture of soil is cut with a stabilizing solution by _D, and a layer L _C of solidifying material wealth formulations are separated. Therefore, consolidated material wealth compounding are prevented from contacting the fluid mixture to have been cut with the stabilizing liquid soil (mixed liquid constituting the layer L _W), and the soil on the ground that has been cut with a stabilizing solution only fluid mixing (mixing liquid constituting the layer L _W) is discharged as a slurry. For this reason, since the rich blended solidified material is hardly discharged to the ground side, the consumption of the solidified material can be reduced as compared with the prior art.

Furthermore, in the illustrated embodiment, since the slurry collection mechanism 2 is a mixture of the stable liquid discharged to the ground side and the cut soil, the slurry around the construction site may be contaminated by the slurry ejected to the ground side. Absent.
Then, the slurry recovered by the slurry recovery mechanism 2 (mixture of the stabilizing liquid and the cut soil) is conveyed to the slurry processing mechanism 4, and the cellulolytic enzyme is added from the enzyme supply source 5, so that the slurry becomes water and It becomes a mixture of soil only and is no longer an industrial waste. Therefore, it is not necessary to transport to the processing facility, and the slurry processing cost can be saved.

Here, in recent years, diffusion of groundwater contaminated with radioactive substances (for example, around the reactor building) has become a problem. According to another embodiment different from that described above with reference to FIGS. 1 to 7, such a problem can be solved.
Here, based on FIG. 8, the above-described problem (diffusion of groundwater contaminated with a radioactive substance) will be described.

In FIG. 8, in preparation for a case where groundwater WG1 contaminated with radioactive material flows out from the reactor building 21 (including radioactive material and groundwater storage facilities: the same applies hereinafter) into the ground G. A continuous wall 22 (for example, a frozen soil wall) is formed so as to surround 21. The continuous wall 22 blocks the flow of the groundwater WG1 containing radioactive material that flows out and diffuses from the reactor building 21 into the ground, and the contaminated groundwater WG1 flows out and diffuses beyond the frozen soil wall 22 to the outside. This is to prevent this.
In addition, the code | symbol 23 in FIG. 8 is an apparatus for forming a frozen earth wall.

However, the diffusion of the contaminated groundwater WG2 that flows out (leaks) from the reactor building 21 into the ground directly below it cannot be prevented with the continuous wall 22 alone.
As apparent from FIG. 8, the flow of the contaminated groundwater WG22 that flows deeper in the ground than the continuous wall 22 cannot be blocked.
An embodiment for solving such a problem will be described with reference to FIGS.

As shown in FIG. 9, a zeolite layer (L _Z : zeolite bottom plate) extending horizontally in the ground G and below the reactor building 21 by the method according to the embodiment of FIGS. 1 to 7. Form.
The thickness B of the zeolite deck slabs L _Z is sufficiently adsorbed while groundwater WG2 contaminated with radioactive material is passed through the zeolite deck slabs L _Z (transmission), cesium encompassed the groundwater WG2 is Zeolite zeolite bottom plate L _Z The thickness is set as much as possible. The thickness is case-by-case depending on the degree of contamination and various conditions.
Further, the horizontal range of the zeolite deck slabs L _Z is runoff of groundwater WG2 contaminated with radioactive material exiting (leaking) from the reactor building 21, is set in a range in which the diffusion path is fully covered.

By forming the zeolite base plate L _Z shown in FIG. 9, zeolites because they have chemical properties of adsorbing cesium is the main component of the radioactive material, flows out from the reactor building 21 in the ground of the direction just below ( leakage), groundwater WG2 to spread, when passing through the zeolite deck slab L _Z, cesium adsorption, are removed. Here, since cesium occupies most of the radioactive material, if cesium can be removed, the concentration of the radioactive material in the groundwater WG2 is reduced to a value that does not cause a problem, that is, a reference value or less.
The groundwater WG1 flowing over the zeolite deck slabs L _Z is blocked by a continuous wall 22, it does not diffuse.
In order to prevent the spread of contamination groundwater WG2, the continuous wall 22 and zeolite deck slabs L _Z are connected.

Figure 10 is a similar procedure to the embodiment shown in Figures 1-7, show a process of forming a zeolite base plate L _Z extending in a horizontal direction.
As shown in FIG. 10, the digging hole H is drilled in the ground G, the injection device 1 is inserted into the digging hole H, and the jetting device 1 while jetting a fluid (partition forming material) that cuts the ground G from the jetting device 1. The step of rotating (moving up) in the vertical direction is the same as in FIGS.
While the injection device 1 is jetting the jet J of the partition forming material and cutting the ground G, it is rotated and pulled up vertically, but, as in the embodiment shown in FIGS. A layer L _D (separation layer) of the mixture with the cut soil is formed.

And in the process shown in FIG. 10, it replaces with the solidification material in embodiment of FIGS. 1-7, and a zeolite is discharged in the ground from the discharge outlet 11 provided in the lower end of the injection apparatus 1. FIG.
Here, since the separation layer L _D is interposed, discharged zeolite stabilizer and injected from the discharge port 12 was, without mixing the cutting soil by jet of stabilizer, zeolite bottom plate extending in the horizontal direction _LZ is formed.

In other words, by injecting the stabilizing liquid from the injection device 1 into the ground, cutting and stirring the ground G, and pulling it up in the vertical direction while rotating around the axis of the injection device 1, FIG. similar to the embodiment shown, the layer L _D of a mixture of a layer L _W of a mixture of which is cut a stable liquid soil, and soil is cut a partition forming material _(separation layer) is formed. Then, the zeolite layer Lz (zeolite bottom plate) is formed by discharging (injecting) the zeolite into the ground from the injection device 1.
Between the layers L _W and zeolite layers Lz mixtures to have been cut with the stabilizing liquid soil (zeolite deck slab), so the separation layer L _D constituted by the partition-forming material is interposed, the layer L _W The stable liquid and the cut soil are prevented from mixing into the zeolite layer Lz (zeolite bottom plate), and the separated state is maintained.

The process shown in FIG. 10 is continued until the zeolite layer Lz (zeolite bottom plate) has a predetermined thickness at a predetermined vertical position (depth) in the ground.
Cross-sectional shape of the zeolite layer Lz (zeolite deck slabs) (i.e., horizontal extent of the zeolite deck slabs L _Z) is a circular cross-section similar to the embodiment shown in FIGS. 1-7. However, if necessary contaminated water spreading, the shape of the zeolite deck slabs L _Z noncircular (e.g. semi-circular, fan-shaped) may be a.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Injection apparatus 2 ... Slurry collection | recovery mechanism 3 ... Slurry conveyance line 4 ... Slurry processing mechanism 5 ... Enzyme supply source 6 ... Built-in mechanism 7 ... Partition formation material supply source 8 ... Stabilizing liquid supply source 9 ... Solidifying material supply source 10 ... Switching valve 11 ... Discharge port 12 ... Injection port 13 ... Solidifying material introducing part 14 ... Stabilizing liquid introducing part , Cum partition forming material introduction part 15 ... inner pipe (injection device)
16 ... Outer pipe (injection device)
17 ... pipe G ... Ground H ... wellbore _L C layer ... solidifying material _L D ... partition-forming material layer (isolation layer)
L _W ... stabilizer and a layer 21 ... reactor building 22 ... continuous wall of a mixture of cut soil WG1, WG2, ... layers of contaminated groundwater _L Z ... zeolite (Zeolite bottom plate)

Claims (2)

A step of drilling a drilling hole in the ground to be improved, a step of inserting an injection device into the drilling hole and rotating the injection device in a vertical direction while injecting a fluid for cutting the ground from the injection device, and an injection device A step of injecting the solidified material from
The step of rotating the injection device while moving the fluid for cutting the ground from the injection device to move in the vertical direction includes the step of cutting the ground by injecting the partition forming material, and the stabilizing liquid after injecting the partition forming material. A ground improvement method characterized by having a step of spraying solidified material while spraying the ground while cutting the ground. Recovering the mixture of the stable liquid discharged to the ground side and the cut soil by a slurry recovery mechanism;
The ground improvement construction method of Claim 1 which has the process of conveying the slurry collect | recovered with the slurry collection | recovery mechanism to a slurry processing mechanism, and adding a degrading enzyme from an enzyme supply source.

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