JP7548766B2 - Soil cement diaphragm wall construction method - Google Patents

Description

The present invention relates to a method for constructing soil cement underground diaphragm walls.

The soil cement diaphragm wall construction method has been known for some time as a construction method for earth retaining walls and water cutoff walls to prevent the diffusion of pollutants.

This soil cement diaphragm wall construction method is carried out using a soil cement construction machine such as an auger mixer. The construction method begins with the excavation process, in which the soil cement construction machine is moved and positioned, and then a mixture of excavated soil and cement milk is created while adding cement milk as an excavation injection material from the tip of the soil cement construction machine. This mixture maintains the stability of the trench wall, and excavation is continued to the bottom while maintaining the appropriate fluidity.

Next, in the solidification process, a soil cement construction machine excavates to the bottom of the excavation, and then adds an appropriate amount of cement milk as a solidification agent to the mixed soil created in the excavation process, while mixing and stirring it and pulling it up, creating soil cement with a softness suitable for inserting the core material in the next process. Then, in the core material insertion process, a crawler crane or the like is used to insert a core material such as an H-shaped steel beam into the soil cement.

In this way, the conventional soil cement diaphragm wall construction method consists of a set of three steps: excavation, solidification, and core material insertion. A continuous solidified wall is constructed by repeating the steps in this order without any gaps between each step.

Meanwhile, the construction machines used to build the above-mentioned soil cement diaphragm walls include column-type, horizontal multi-axis, cutter chain, etc., and each of these construction machines has its own unique capabilities, such as excavation and construction performance, mixing performance, soil adaptability, wall thickness adaptability, and deep construction capability. In the construction plan, the construction machine to be used is selected and used alone, taking into consideration the characteristics of the construction machine to be used according to the required characteristics of the soil cement diaphragm wall to be constructed.

The main reason why the above three processes, the excavation process, solidification process, and core material insertion process, are grouped together and carried out without any gaps between each process is due to the following constraints. First, in the excavation process, cement milk is used as the excavation injection material, so the cement hydration reaction begins as soon as excavation begins. Therefore, it is necessary to finish inserting the core material before the soil cement hardens, and there is a time constraint due to the cement hydration reaction.

In addition, when constructing a deep soil cement diaphragm wall, the excavation process takes a long time, and the hydration reaction of the cement milk progresses when inserting the core material, making it difficult to insert the core material. In addition, if an obstacle is present during excavation, the excavation process may take longer than planned, making it impossible to insert the core material.

Furthermore, after the excavation and solidification processes are carried out using a soil cement construction machine, the core material insertion process is carried out using a core material insertion crane. The fact that two types of construction machinery, the soil cement construction machine and the core material insertion crane, are used together as a set is also a reason why the above three processes must be carried out as a set.

In this way, with conventional soil cement diaphragm wall construction methods, due to the above-mentioned restrictions on construction machinery, the solidification process and core material insertion process cannot be carried out during the excavation process; the core material insertion process and excavation process cannot be carried out during the solidification process, and the excavation process and solidification process cannot be carried out during the core material insertion process. In other words, since the other two of the three processes cannot be carried out while one of them is being carried out, the operating rate of the construction machinery is poor, resulting in a problem of significantly poor construction efficiency.

In response to these problems, the applicant has proposed a construction method that aims to improve construction efficiency and reduce construction costs by using two construction machines in parallel at the same time. For example, in the proposals of Patent Documents 1 and 2, two construction machines are used in parallel at the same time, with the leading construction machine 1 excavating the original ground while injecting non-hardening air bubbles to create aerated soil, and the trailing construction machine adding solidification material slurry to the aerated soil while mixing and kneading it to create solidified soil. In these proposals, partitions or core materials are used as partitions in the adjacent areas where the aerated soil and solidification material slurry are mixed to improve the quality of the mixture.

In addition, in the proposal of Patent Document 3, a leading construction machine adds and mixes air bubbles and a small amount of solidification material slurry during excavation, lightly solidifying the air-bubble mixed soil. Then, a trailing construction machine excavates the lightly solidified air-bubble mixed soil, and further adds and mixes solidification material slurry, utilizing the self-supporting nature of the air-bubble mixed soil to maintain good quality at the boundary.

Patent No. 5513182 Patent No. 6466101 JP 2019-15022 A

According to the above proposal, the excavation and solidification processes are carried out using construction machines suitable for each process, which is superior to the conventional soil cement diaphragm wall construction method in which both the excavation and solidification processes are carried out using a single construction machine, in that it improves the quality of the solidified wall and shortens the construction period. However, in recent years, there has been a demand for the construction of soil cement diaphragm walls of even higher quality and for a shorter construction period.

The present invention was made in consideration of the above circumstances, and aims to provide a soil cement diaphragm wall construction method that improves the quality of soil cement diaphragm walls and reduces construction costs by improving workability.

In order to solve the above problems, the present invention has the following features.
First, the soil cement underground diaphragm wall construction method of the present invention includes an excavation step in which an excavation area is created consisting of a mixture of excavated soil and the non-hardening grouting material by excavating the soil while discharging a non-hardening grouting material from the tip of a single-axis or multi-axis column-type construction machine;
A soil cement underground continuous wall construction method having a solidification process in which a solidification material slurry is discharged from the tip of a horizontal multi-axis construction machine after the excavation process, mixed with the mixed soil of the mixed soil area, and solidified to create a solidified area,
The excavation process provides an unconstructed area at a predetermined interval based on the excavation width of the horizontal multi-axis construction machine to create a mixed soil area;
The method is characterized in that the solidification process is carried out on a mixed soil area adjacent to the unconstructed area to form a solidified area, and then the excavation process and the solidification process are carried out on the unconstructed area adjacent to the solidified area.
Secondly, in the soil cement underground continuous wall construction method of the first invention, it is preferable that the interval W' based on the excavation width of the horizontal multi-shaft construction machine is expressed as W' = W - Lo (Lo includes 0), where W is the excavation width of the horizontal multi-shaft construction machine and Lo is the lap length.
Thirdly, in the soil cement diaphragm wall construction method of the first or second invention, it is preferable to have a core material inserting step of inserting a core material into the solidified region after the solidification step.
Fourthly, in the soil cement diaphragm wall construction methods of the first to third inventions, it is preferable to use air bubbles or air bubbles and water as the non-hardening injection material.
Fifth, in the soil cement diaphragm wall construction method of the fourth invention, it is preferable to adjust the amount of air bubbles added so that the TF value is in the range of 150 to 220 mm.
Sixth, in the soil cement underground continuous wall construction method of the first to fifth inventions, it is preferable to use, as the non-hardening injection material, a swelling water-absorbing polymer that has absorbed water and expanded, or a swelling water-absorbing polymer dispersion in which water has been added to a swelling polymer that has absorbed water and expanded.
Seventh, in the soil cement diaphragm wall construction method according to the first to sixth inventions, it is preferable that an antifoaming agent is mixed into the solidification material slurry.

According to the soil cement diaphragm wall construction method of the present invention, two soil cement construction machines, a column-type construction machine and a horizontal multi-axis construction machine, which have different construction capabilities, are used simultaneously in a specific order, and by maximizing the construction capabilities of each machine, it is possible to improve the quality of the soil cement diaphragm wall and reduce the construction cost. In addition, by mixing tiny air bubbles with the excavated soil during excavation construction and creating a non-hardening air-bubble mixed soil wall, it is possible to operate the two construction machines in parallel.

1A and 1B are schematic cross-sectional views and a schematic plan view of the construction process of the present invention, in which (A) shows the excavation process, (B) shows the solidification process, and (C) shows the core material insertion process. 1 is a graph showing the relationship between the air foam addition rate and the TF value in sandy soil with a water content (W: 10 to 25%). 1A and 1B are schematic cross-sectional views and a schematic plan view of the construction process of another embodiment of the present invention, in which (A) shows the excavation process, (B) shows the solidification process, and (C) shows the core material insertion process. FIG. 1 is a schematic explanatory diagram showing an overlapping portion between an unfinished area and the excavation width of a horizontal multi-axis construction machine. FIG. 2 is a plan view showing an outline of the progress of the construction method of the present invention.

The soil cement underground diaphragm wall construction method of the present invention includes an excavation process in which excavation is performed while a non-hardening grout material is discharged from the tip of a single-axis or multi-axis column-type construction machine, and an excavation area is created with a mixture of excavated soil and non-hardening grout material, and a solidification process in which a solidification material slurry is discharged and mixed from the tip of a horizontal multi-axis construction machine after the excavation process, and solidified at the same time as excavation.

Then, in the excavation process, a mixed soil area is created by providing unconstructed areas at a predetermined interval based on the excavation width of the horizontal multi-axis construction machine, and a solidification process is carried out on the mixed soil area adjacent to the unconstructed area to form a solidified area, after which the excavation process and the solidification process are carried out on the unconstructed area adjacent to the solidified area.

The following describes an embodiment of the present invention with reference to the drawings. Figure 1 shows a schematic cross-sectional view (1) and a schematic plan view (2) of the construction process of the present invention, where (A) shows the excavation process, (B) shows the solidification process, and (C) shows the core material insertion process.

<Drilling process>
The procedure for the soil cement underground continuous wall construction method of this embodiment is as follows: first, a single- or multi-axis column-type construction machine 1 is used to excavate the original ground to be constructed while adding a non-hardening injection material from the tip of the machine, thereby creating an excavation area 11 consisting of excavated soil and mixed soil.

It is preferable to select and use a single-axis or multi-axis column-type construction machine 1 that has better excavation capabilities than the horizontal multi-axis construction machine 2 that performs the next solidification process, and it is particularly preferable to use a three-axis or five-axis column-type construction machine 1. Specifically, a three-axis or five-axis auger drilling and kneading shaft construction machine can be suitably used. Note that the embodiment shown in Figure 1 (A) shows the excavation process using a three-axis column-type construction machine 1.

By using the column-type construction machine 1 with excellent excavation capabilities, the solidification process will not be delayed even if the solidification process is carried out immediately after the excavation process. Note that in this case, construction efficiency means the construction progress speed per unit time, and good construction efficiency specifically means that the progress time of the excavation process is shorter than that of the following solidification process.

As the non-hardening injection material discharged from the tip of the column-type construction machine 1, it is preferable to use air bubbles or air bubbles and water. The mixing ratio of the excavated soil to air bubbles or air bubbles and water varies depending on the physical properties of the excavated soil and the required fluidity of the mixed soil. In general, when the fluidity of the mixed soil is expressed as a table flow value (hereinafter abbreviated as TF value) (JIS R 5201:2015), the TF value is preferably in the range of 150 to 220 mm, and more preferably 170 to 200 mm as an empirical value, in order to perform the next solidification process appropriately and to properly insert the core material 31 after the solidification process and to achieve both the fluidity of the mixed soil and the stability of the wall.

Figure 2 shows a graph of the relationship between the foam addition rate and TF value for sandy soil with a water content (W: 10-25%). The foam addition rate refers to the mass percentage of foaming agent relative to the dry weight of the excavated soil. This graph shows that increasing the foam addition rate easily increases the TF value to 150-220 mm.

In addition, when the TF value of the mixed soil is set under the above conditions, from the standpoints of workability and economy, if the excavated soil is clayey, it is preferable to have approximately 0.3 ^m3 of air bubbles and 0.3 ^m3 of water per 1 ^m3 of excavated soil, and if the excavated soil is sandy, it is preferable to have approximately 0.2 ^m3 of air bubbles and 0.1 ^m3 of water.

On the other hand, if the air foam addition rate is increased, the fluidity improves, but the specific gravity of the mixed soil decreases. Therefore, when considering the stability of the wall, the specific gravity needs to be 1.05 or more, and the amount of air foam injection for this needs to be kept at about 0.8 ^m3 / ^m3 or less.

Furthermore, a foaming agent can be used to generate the desired bubbles. As the foaming agent, a known surfactant can usually be used, but among them, a foaming agent that is difficult to defoam even when mixed with the excavated soil, has excellent chemical stability against acids and alkalis, and has excellent foaming ability is desired, and for example, an alkyl sulfate surfactant can be preferably used.

Specifically, it is suitable to use WTM foaming agent, an alkyl sulfate surfactant (WTM foaming agent stock solution from Floric Co., Ltd. diluted 20 times with clean water) foamed 25 times to a specific gravity of 0.04 and a mode of about 100 μm. According to the results of using the above foam, it has been confirmed that the foamed soil can be used suitably for one week without any change in the fluidity, etc. of the foamed soil. For this reason, it is desirable to carry out the next solidification process within one week after the end of the excavation process.

In addition, the non-hardening grout of this embodiment can use a swelling polymer that has absorbed water and swelled, or a swelling polymer dispersion in which water has been added to a swelling polymer that has absorbed water and swelled. When using a swelling polymer dispersion as the non-hardening grout, it is preferable to use 0.3 ^m3 of swelling polymer dispersion for clayey soil and 0.2 m3 for sandy soil per ^m3 of excavated soil in order to achieve a TF value of 170 mm or ^more .

There are three types of swelling polymers: starch-based, cellulose-based, and polymer-based. In the case of a synthetic polymer swelling polymer (GEOSAP from Sanyo Chemical Industries), it is preferable to add 0.5 to 1.5 kg of GEOSAP per ^{1 m3} of clean water, preferably 1 kg per 1 ^m3 of water, and use the resulting dispersion that has absorbed sufficient water as a non-hardening injection material.

The column-type construction machine 1 excavates to the construction depth while adding the non-hardening grouting material, and then pulls it up, creating an excavation area 11 made of a mixture of excavated soil and non-hardening grouting material. This mixed soil excavation area 11 remains stable for a specified period of time and retains the fluidity required for construction, so the next solidification process can be carried out properly even after a long time has passed.

<Solidification process>
Next, a solidification process is performed on the excavation area 11 created by the excavation process. FIG. 1(B) shows the solidification process in this embodiment. The horizontal multi-shaft construction machine 2 used in the solidification process is a construction machine with excellent mixing ability. Specifically, a BC excavator (Bauer Maschinen) and an SMX excavator (Toa Tone Boring) can be exemplified. The horizontal multi-shaft construction machine 2 injects solidification material slurry from the tip into the excavation area 11 created by the column-type construction machine 1 in the excavation process, mixes and stirs the solidification material slurry with the mixed soil, and sinks it down. After arriving at the bottom, the solidification material slurry is further injected, mixed, stirred, and pulled up. This allows the solidification area 22 of the soil cement underground wall to be created.

Normally, when a horizontal multi-axis construction machine 2 is used to excavate the original ground on which construction is to be performed, the horizontal multi-axis construction machine 2 has a relatively slow construction progress speed, so excavation takes a long time. In contrast, in the soil cement diaphragm wall construction method of the present invention, first, an excavation area 11 is created using a column-type construction machine 1, and in the solidification process, excavation is performed by tracing the excavation area 11, and the mixed soil and solidification agent slurry in the excavation area 11 are stirred, mixed, and solidified. This means that there is little excavation and mixing stress, and the solidification process can be completed in a very short construction time.

The excavation area 11 by the columnar construction machine 1 is an excavation area 11 created by an auger excavator or the like, so an excavation groove is usually formed in the shape of connected cylinders as shown in FIG. 1(A). On the other hand, in the next solidification process, the solidification process is performed on the excavation area 11 using a horizontal multi-axis construction machine 2, so that the excavation groove becomes a solidified area 22 with a regular rectangular shape when viewed from above as shown in FIG. 1(B). From this perspective, it is preferable that the excavation width of the horizontal multi-axis construction machine 2 used in the solidification process is equal to or larger than the excavation width of the columnar construction machine 1.

In addition, it is desirable to select a horizontal multi-axis construction machine 2 that, under the conditions of the solidification process described above, has a construction progress speed per unit time that is approximately the same as that of the column row construction machine 1 used in the excavation process. This makes it possible to carry out the solidification process immediately after the excavation process, and significantly shortens the construction period.

In addition, in the solidification process, when a BC excavator such as that shown in Figures 1 and 3 is used, the solidification agent slurry discharged from the tip of the horizontal multi-axis construction machine 2 is uniformly mixed into the mixed soil by the rotating cutter wheel, creating a high-quality solidified area 22. Note that cement milk or the like can be suitably used as the solidification agent slurry used in the present invention.

In addition, an antifoaming agent can be added to the solidification material slurry. In the solidification process, an antifoaming agent is added to eliminate the air bubbles in the mixed soil created in the excavation process, thereby increasing the strength of the solidified area 22. The antifoaming agent can be appropriately selected depending on the foaming agent. In addition, in the solidification process, it is desirable that the fluidity of the excavation area 11 immediately after the horizontal multi-axis construction machine 2 is raised be 170 mm or more in terms of TF value, taking into account the core material insertion process described below.

In addition, in the soil cement diaphragm wall construction method of the present invention, as shown in Figure 3, in the solidification process, it is also possible to excavate deeper than the excavation depth in the excavation process. Specifically, if the reasonable construction depth in the excavation process is D and the planned depth is D', first, as shown in Figure 3 (A), the column-type construction machine 1 excavates to a depth D while discharging the non-hardening grout from the tip of the tunneling machine, creating an aerated soil mixture of the excavated soil and the non-hardening grout. In this case, the TF value of the aerated soil mixture is preferably 150 to 200 mm.

Then, as shown in FIG. 3(B), in the solidification process, further excavation is performed to the planned depth D', and solidification material slurry is discharged from the tip of the horizontal multi-axis construction machine 2 and pulled up while being mixed with the mixed soil, to construct a soil cement underground wall in the solidification area 22. Then, as shown in FIG. 3(C), a core material 31 is inserted before the soil cement underground wall hardens.

<Core Insertion Process>
In addition, in the soil cement diaphragm wall construction method of this embodiment, the core material 31 can be inserted after the solidification step as necessary. FIG. 1(C) shows the core material insertion step of this embodiment. In the core material insertion step of this embodiment, the core material 31 is inserted using a crane for inserting the core material, such as a crawler crane. As the core material 31 to be inserted, a core material generally used for reinforcing the solidified area 22 that is constructed can be used, and specifically, for example, a steel material such as an H-shaped steel, a precast concrete wall, or a steel wall can be used. By inserting the core material 31 into the solidified area 22, a soil cement diaphragm wall with excellent bending strength characteristics can be constructed.

When performing the core material insertion process, the solidification reaction begins with the mixing of the mixed soil and the solidification agent slurry in the solidification process, so it is preferable to insert the core material 31 at a stage when the solidification reaction of the solidification agent slurry has not progressed as much as possible, that is, immediately after the solidification process.

<Installation procedure>
The procedure of the soil cement underground continuous wall construction method of the present invention is characterized in that the excavation process is used to create a mixed soil area by providing unconstructed areas 12 at a predetermined interval, and then a solidification process is performed on the mixed soil area to create a solidified area 22, and then an excavation process and a solidification process are performed on the unconstructed area 12.

Here, in the soil cement underground diaphragm wall construction method of the present invention, the predetermined interval of the unconstructed area 12 is an interval determined based on the excavation width of the horizontal multi-shaft construction machine 2 used in the solidification process, and can be determined by W' = W - Lo, where W' is the interval, W is the excavation width of the horizontal multi-shaft construction machine 2, and Lo is the lap length. It is preferable to compare the excavation widths of the columnar construction machine 1 and the horizontal multi-shaft construction machine 2 and set the excavation width W to the larger one, but since the width of the columnar construction machine 1 is generally about 1450 to 2000 mm and the width of the horizontal multi-shaft construction machine 2 is 2350 mm, the excavation width W is usually set based on the excavation width of the horizontal multi-shaft construction machine 2. The lap length Lo means the difference between the excavation width of the unconstructed area 12 and the horizontal multi-shaft construction machine 2, that is, the dimension of the overlapping part of the excavation width of the solidification area 22 and the horizontal multi-shaft construction machine 2.

As shown in FIG. 4, when overlap lengths Lo1 and Lo2 occur that span the solidified areas 22 on both sides of the unconstructed area 12 and the excavation width of the horizontal multi-axis construction machine 2, Lo is set as the total dimension of Lo1 and Lo2. By setting Lo under the above conditions, it is possible to construct a reliable soil cement underground continuous wall without leaving any unconstructed area 12. Furthermore, when the excavation process and the solidification process can be carried out with high dimensional accuracy, Lo in the overlapping portion can be set to 0 or as close to 0 as possible.

Furthermore, the spacing W' of the unconstructed area 12 in the soil cement diaphragm wall construction method of the present invention is usually set based on the width of one horizontal multi-axis construction machine 2, but W' can also be set to an integer multiple of the width of one horizontal multi-axis construction machine 2 depending on the conditions at the construction site. In this case, the integer multiple is usually considered to be 2 to 3 times. In addition, as the construction procedure for the unconstructed area 12 in this case, the excavation process and solidification process may be performed on the unconstructed area 12W' all at once, or the excavation process and solidification process may be performed in multiple divided steps.

The procedure of the soil cement diaphragm wall construction method of the present invention will be described in more detail below. Figure 5 shows the progress of the soil cement diaphragm wall construction method of the present invention in plan views of steps 1 to 9. In Figure 5, step 1 shows the excavation process, step 2 shows the excavation process and solidification process, and steps 3 and 4 show the planar positions during the excavation process, solidification process, and core material insertion process. Step 5 and onwards show the process of carrying out the excavation process, solidification process, and core material insertion process in parallel in the unconstructed area 12, which is a feature of the present invention.

First, in step 1, an excavation process is carried out to create an excavation area 11(1). Next, in step 2, a solidification process is carried out on the excavation area 11(1) to create a solidified area 22(1). At the same time, a new excavation area 11(3) is created by the excavation process, leaving a gap for the unconstructed area 12(2) adjacent to the solidified area 22(1).

In step 3, a core material insertion process is carried out in the solidified area 22(1) to construct the soil cement underground wall (1). At the same time, a solidification process is carried out in the excavated area 11(3) to create the solidified area 22(3), and a new excavation process is carried out to create the excavated area 11(5), leaving a gap for the unconstructed area 12(4).

In step 4, a core material insertion process is carried out in the solidified area 22 (3) to construct the soil cement underground wall (3). At the same time, a solidification process is carried out in the excavated area 11 (5) to create the solidified area 22 (5), and a new excavation process is carried out to create the excavated area 11 (7), leaving a gap for the unconstructed area 12 (6).

Next, in step 5, a core material insertion process is carried out in the solidified area 22 (5) to construct the soil cement underground wall (5). At the same time, a solidification process is carried out in the excavated area 11 (7) to create the solidified area 22 (7), and a new excavation process is carried out in the unconstructed area 12 (2) to create the excavated area 11 (2).

In step 6, a core material insertion process is carried out in the solidified area 22 (7) to construct the soil cement underground wall (7). At the same time, a solidification process is carried out in the excavation area 11 (2) to create the solidified area 22 (2), and a new excavation process is carried out in the unconstructed area 12 (4) to create the excavation area 11 (4).

In step 7, a core material insertion process is carried out in the solidified area 22(2) to construct the soil cement underground wall (2). At the same time, a solidification process is carried out in the excavated area 11(4) to create the solidified area 22(4) and to create the excavated area 11(6) in the unconstructed area 12(6).

In step 8, a core material insertion process is carried out in the solidified area 22 (4) to construct the soil cement underground wall (4). At the same time, a solidification process is carried out in the excavation area 11 (6) to create the solidified area 22 (6).

Finally, in step 9, a core material insertion process is carried out in the remaining solidified area 22 (6) to construct the soil cement underground wall (6). By following the above steps 1 to 9 in sequence, a stable, high-quality soil cement underground diaphragm wall can be constructed.

The soil cement underground diaphragm wall construction method of the present invention has been explained above based on an embodiment, but the present invention is not limited to the above embodiment in any way, and various modifications are possible within the scope of the gist of the invention.

For example, in the above embodiment, the construction of a linear soil cement underground continuous wall was described, but it is also possible to change the angle while leaving unconstructed areas 12 according to the design, or to adjust the excavation width according to the location.

In addition, in the above embodiment, the core material 31 is inserted into the solidified area 22 in the core material insertion process to construct a soil cement underground continuous wall, but depending on the design, it is also possible to construct a soil cement underground continuous wall without inserting the core material 31.

As explained above, in the soil cement diaphragm wall construction method of the present invention, first, while leaving an unconstructed area 12, the excavation area 11 and the solidification area 22 are created using a column-type construction machine 1 and a horizontal multi-axis construction machine 2 with different construction capabilities in parallel, a core material insertion process is carried out, and a soil cement diaphragm wall is constructed. After the soil cement diaphragm wall with a gap is constructed, an excavation area 11 and a solidification area 22 are created in the previously left unconstructed area 12, a core material insertion process is carried out, and a soil cement diaphragm wall is constructed. This makes it possible to construct a high-quality soil cement diaphragm wall at low cost with high flexibility in construction planning.

1 Pillar row construction machine 11 Excavation area 12 Unconstructed area 2 Horizontal multi-axis construction machine 22 Solidification area (soil cement underground wall)
3 Core material insertion crane 31 Core material

Claims (7)

An excavation step of excavating while discharging a non-hardening grout from the tip of a single-axis or multi-axis column-type construction machine to create an excavated area consisting of a mixture of excavated soil and the non-hardening grout;
A soil cement underground continuous wall construction method having a solidification process in which a solidification material slurry is discharged from the tip of a horizontal multi-axis construction machine after the excavation process, mixed with the mixed soil in the excavation area , and solidified to create a solidification area,
After the excavation area is created by the excavation process, the solidification process is performed on the excavation area to create a solidified area, and at the same time, an unconstructed area is provided at a predetermined interval based on the excavation width of the horizontal multi-axis construction machine from the solidified area , and a new excavation area is created by the excavation process .
A soil cement underground continuous wall construction method, characterized in that the solidification process is carried out on the excavated area adjacent to the unconstructed area to form a solidified area, and then the excavation process and the solidification process are carried out on the unconstructed area adjacent to the solidified area. The soil cement underground diaphragm wall construction method according to claim 1, characterized in that the interval W' based on the excavation width of the horizontal multi-axis construction machine is expressed as W' = W - Lo (Lo includes 0), where W is the excavation width of the horizontal multi-axis construction machine and Lo is the lap length. A soil cement underground continuous wall construction method as described in claim 1 or 2, characterized in that in the solidification process, when the solidification state is such that a core material can be inserted even after the solidification material slurry is ejected, a core material insertion process is included in which a core material is inserted into the solidified area. The soil cement underground diaphragm wall construction method according to any one of claims 1 to 3, characterized in that air bubbles or air bubbles and water are used as the non-hardening injection material. The soil cement underground diaphragm wall construction method described in claim 4, characterized in that the amount of air bubbles added is adjusted so that the TF value is in the range of 150 to 220 mm. The method for constructing a soil cement underground diaphragm wall according to any one of claims 1 to 5, characterized in that a swelling water-absorbing polymer that has absorbed water and expanded, or a swelling water-absorbing polymer dispersion in which water is added to a swelling polymer that has absorbed water and expanded, is used as the non-hardening injection material. The soil cement underground diaphragm wall construction method according to any one of claims 1 to 6, characterized in that an antifoaming agent is mixed into the solidification material slurry.

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