JP2698772B2 - Slag graft system underground wall construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of continuously constructing an underground continuous wall using excavated earth and sand in an original ground as an aggregate.

[0002]

2. Description of the Related Art Conventionally, in constructing a vertical underground continuous wall having a constant width in the ground, a trench is excavated by a drilling means provided in the excavator while moving an excavator inserted into the ground in a lateral direction. The excavated sediment generated during the excavation of the trench is lifted to the ground, the excavated sediment lifted to the ground is broken down, and the mixture of the excavated sediment and the cement liquid obtained by mixing the cement solution is returned to the trench. A method of constructing a middle continuous wall is known from Japanese Patent Application Laid-Open No. Hei 7-138941.

[0003]

In the above-mentioned prior art, the excavator is moved laterally to discharge the excavated earth and sand while forming a groove, but the excavator is moved laterally. When excavating the ground by anhydrous excavation, the resistance of the ground in the lateral traveling direction is large, making it difficult to move laterally while excavating with an excavator, and because it is anhydrous excavation, the side wall of the excavated trench collapses The excavator located in the ditch is buried with collapsed earth and sand, making it difficult for the excavator to move in the lateral direction.
In addition, there is a problem that an accurate groove cannot be formed. In particular, when a deep groove is continuously excavated in the lateral direction by anhydrous excavation, the resistance of the ground on the traveling direction side at the time of the excavation is further increased. When the excavator is buried due to collapse of the side wall of the excavated trench, there is a problem that the excavator cannot move not only in the horizontal direction but also in the vertical direction.

[0004] For this reason, when the excavator is moved laterally to lift the excavated earth and sand while forming a groove, in order to facilitate excavation, the excavator is excavated while discharging water to move the excavator in the lateral direction. It is conceivable to move to form a ditch and discharge a mixture of water and excavated earth to the ground. However,
Even when excavating by injecting water, the side wall of the excavated trench is still easily collapsed, and the excavator located in the trench may be buried in collapsed earth and sand. In particular, when the sandy soil collapses and the excavator is buried, there is a problem that the sandy soil is tightened by water and the excavator cannot move further.

[0005] In this case, the collapse of the side wall of the groove can be prevented as the specific gravity and viscosity of the filling material filled in the groove increases.
When digging while excavating while moving the excavator laterally,
By digging while moving the excavator in the lateral direction while injecting cement milk having higher specific gravity and viscosity than water instead of water, excavation in the lateral direction is facilitated, and a mixture of cement milk and excavated earth and sand It is conceivable to prevent collapse of the side wall of the groove. However, in this case, the mixture of cement milk and excavated earth and sand is discharged to the ground, and the mixture of cement milk and excavated earth and sand discharged to the ground is further mixed with cement to develop the desired strength. By adjusting the mixture and returning the adjusted mixture into the groove, an underground continuous wall that expresses the desired strength is to be formed. There is a cement component used at the time of excavation in addition to the cement component that is used, and the cement component used at the time of this excavation has undergone a hardening reaction, is difficult to transfer, and
There is a problem that pipes and the like may be clogged, and the amount of cement used as a whole increases.

Further, in the conventional example disclosed in Japanese Patent Application Laid-Open No. 7-138941, the earth and sand discharged to the ground is broken down and mixed with the cement liquid. It is not always possible to make natural soil particles,
The homogeneity of each part of the underground diaphragm wall formed is also impaired. Also, in some cases, large blocks of rock that do not crumble are included, and these large blocks of rock that do not easily dislodge and are not displaced are returned to the ditch as they are,
Piping becomes easier to clog.

[0007] The present invention solves the above-mentioned problems and enables smooth lateral excavation even in a deep groove, prevents collapse of the side wall of the excavated groove, and removes excavated earth and sand from the original ground. As a material, the mixture of the desired composition can be returned to the excavation trench to form an underground continuous wall with uniform strength, and also prevent clogging of pipes and reduce the amount of cement used. It is an object of the present invention to provide a slag graft-based circulating underground wall construction method.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, the slag graft-type circulating underground wall construction method of the present invention is used to construct a vertical underground continuous wall having a constant width in the ground. excavator while moving the inserted excavator 1 in the transverse direction
Excavating means 2 provided on the excavator 1 while discharging slag grout into the ground in the lateral traveling direction ahead of the partition provided on the excavator 1
And the first mixture A in which the slag grout and excavated earth and sand are mixed is discharged to the ground, and the first mixture A discharged to the ground is mixed with a cement component to form a second mixture B. Obtained behind the partition of the excavator 1 in the lateral traveling direction
The second mixture is returned into the side groove 3 .

Further, the first mixture A discharged to the ground is sieved by a sieving means 4 to remove large particles in the excavated earth and sand.
It is also preferable that the mixture B is obtained and the second mixture B is returned to the groove 3 .

It is also preferred that the second mixture B formed on the ground is discharged into the groove 3 by the transport pipe 5 and returned.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. 1 to 3 show an embodiment of an underground continuous wall forming apparatus 6 provided with an excavator 1 used in the present invention. The underground continuous wall forming apparatus 6 is configured by attaching the excavator 1 to a base machine 7. The base machine 7 is provided with a traveling means such as a caterpillar and is capable of self-running. The traveling means such as the caterpillar includes a ground propulsion means 8 for propelling the excavator 1 in the lateral direction on the ground. Has become. Here, the excavator 1 can be freely moved in the lateral direction with respect to the base machine 7 by a lateral movement mechanism, and this may be used as the ground propulsion means 8.

The vertically long frame main body 9 constituting the main body of the excavator 1 is provided with sprockets 10 at both upper and lower ends, and the endless chain 1 is provided between the upper and lower sprockets 10.
The upper sprocket 10 is rotated by a rotating device (not shown) provided on an upper base frame 12 provided above the frame main body 9 to rotate the endless chain 11. ing. Endless chain 11
, A large number of excavating claws 14 are rotatably mounted on a shaft 15. The endless chain 11 rotates so as to move from bottom to top on the front side and to move from top to bottom on the rear side. The endless chain 11 is provided with a stopper 13, and the excavation claw 14 is configured to hold the lateral position by hitting the stopper 13 on the front side of the endless chain 11 as shown in FIG. Is set to have a vertical posture under its own weight. Drilling claw 14
The endless chain 11 provided with is constituted by the excavating means 2. Further, the excavation claw 14 has a bucket shape in the embodiment of FIG. 2, and the endless chain 11 provided with this excavation claw 14 also serves as the discharging means 16.

Injecting portions 20 for injecting slag grout into the ground are provided at a plurality of positions in the vertical direction of the frame main portion 9. The injection unit 20 is provided at the tip of a slag grout supply pipe in which the frame main body 9 is piped up and down, and the slag grout supply pipe is connected to a flag grout supply device installed on the ground by a hose or the like. A partition 17 is provided behind the frame main body 9. The upper end of the partition 17 is connected to and supported by the upper base frame 12. The frame main body 9 and the partition 17 are connected by a connecting member 18. The partition 17 has substantially the same vertical length as the frame main body 9.

The upper base frame 12 is provided with a hopper 19 for receiving a first mixture A in which the excavated earth and sand discharged to the ground by the excavation claws 14 and the slag blowout are mixed. Furthermore,
The base machine 7 is provided with a sieving device which constitutes the sieving means 4 to which the first mixture A is supplied from the hopper 19, and the sieving device further comprises a first mixture sieved to a certain particle size or less by the sieving device. An adjusting device 21 to which A is supplied is provided. The adjusting device 21 mixes cement, water, and the like with the first mixture A to form a second mixture B adjusted and mixed to a design value. ing. The transport pipe 5 is connected to the adjusting device 21, and the transport pipe 5 is attached along a surface of the partition 17 opposite to the frame main body 9. Here, although not shown, a plurality of transport pipes 5 having different levels of the discharge ports 22 at the lower end are partitioned into ones.
7 may be attached. In this case, it is preferable to arrange the plurality of discharge ports 22 at the lower part, the central part, and the upper part of the partition 17 in the vertical direction.

Construction of an underground continuous wall using the underground continuous wall forming apparatus 6 provided with the excavator 1 having the above-described configuration is performed as follows. That is, a vertical hole into which the excavator 1 of the underground continuous wall forming device 6 can be inserted in the ground is excavated in advance, and the underground continuous wall forming device 6 is inserted into the vertical hole.
Excavator 1 is inserted. In the figure, 35 is the ground. With the excavator 1 thus inserted into the vertical hole, the ground propulsion means 8 is driven to move the excavator 1 in the lateral direction. In the figure, the direction of arrow A indicates the moving direction of the excavator 1.
At this time, by rotating the endless chain 11, when the excavation claw 14 moves upward from the bottom on the front side of the endless chain 11, the excavation claw 14 is held in the lateral posture by the stopper 13. Drilling claw 1
As a result, it will rise while excavating, and as a result,
The groove 3 is formed by excavating the ground in front of the ground by the excavation claws 14 in the vertical direction. At this time, the slag grout is injected from the injection unit 20 and the excavation claw 14 is used to dig the front ground
The first mixture A in which the excavated earth and sand and the slag grout are mixed is present in the groove 3, and the first mixture A is scooped by the bucket-shaped excavation claws 14. When the excavation claw 14 moves to the upper end of the endless chain 11, the excavation claw 14 drops from the excavation claw 14 to the hopper 19 and drops the first mixture A. When it comes to the rear side, it descends while maintaining its vertical position under its own weight. When the excavation claw 14 reaches the lower end position of the endless chain 11, the excavation claw 14 rotates by the resistance of the soil and stops against the stopper 13. It is held and the same operation as above is repeated.

The first mixture A charged into the hopper 19
The first mixture A which has been sieved by the sieving means 4 to remove particles having a large particle size in the excavated earth and sand and reduced to a certain particle size or less, and thus sieved to a certain particle size or less. Is supplied to the adjusting device 21, where:
Cement, water, other materials and the like are added and mixed, and the mixture is adjusted to a desired composition to obtain a second mixture B. In this way, the second mixture B adjusted to the desired composition is supplied to the transport pipe 5 and returned from the discharge port 22 at the end of the transport pipe 5 into the groove 3 behind the partition 17. The groove 3 is filled.

In the present invention, the above operation is continuously performed, whereby the underground continuous wall is continuously formed. By the way, in the present invention, when excavating while excavating the excavator 1 inserted in the ground in the lateral direction, excavation is performed while discharging slag grout into the ground. The excavation is facilitated by the discharge of slag grout. Then, the first mixture A in which the excavated earth and sand and the slag grout are mixed is contained in a portion of the excavated groove 3 in front of the partition 17, and the side wall of the groove 3 is prevented from collapsing.

Here, the slag grout used is, for example,
Slag 1000 kg, bentonite 90 kg, water 250
00 kg, and the specific gravity is about 1.25. Since the slag grout is higher in viscosity and higher in specific gravity than water, the first mixture A in which the slag grout and the excavated earth and sand are mixed is located before the partition 17 of the groove 3, and the slag grout is simply excavated. The collapse of the side wall of the groove 3 is prevented as compared with the case where the mixture with the earth and sand is contained.

The slag grout discharged into the ground when the trench 3 is excavated has latent hydraulicity, but in the state of the first mixture A, since calcium such as cement is not added, the slag grout hardens. It does not start, and can be discharged smoothly in the process after discharge to the ground. The first mixture A discharged to the ground by the discharging means 16 is sieved by a sieving device constituting the sieving means 4.
Next, the first mixture A thus sieved to a certain particle size or less is supplied to the adjusting device 21. During the sieving by the sieving means 4 and during the supply of the sieved material to the adjusting device 21, calcium such as cement is not added to the slag grout, so that hardening does not start, and sieving and transport can be performed smoothly. become.

The first mixture A sieved to a certain particle size or less is supplied to an adjusting device 21. The adjusting device 21 mixes the first mixture A with cement, water, other materials, etc. And the second mixture B
To form The second mixture B thus formed is sent to the transport pipe 5, and the groove 3 on the rear side of the partition 17 in the lateral traveling direction of the mobile excavator 1 is discharged from the discharge port 22 provided in the transport pipe 5.
The second mixture B is discharged into the inside of the groove 3 to fill the groove 3 on the rear side of the partition 17. In this case, the filled second mixture B was adjusted by sieving on the ground and mixing with cement on the ground, although the excavated earth and sand produced by the excavation of the trench 3 was used as aggregate, and thus the design value was adjusted. As a homogeneous mixture.

The second mixture B filled on the rear side of the partition 17 of the groove 3 induces the hydraulic setting of the slag in the slag grout having latent hydraulic properties to harden the slag and the cement, thereby causing the cement and the cement to harden. Thus, a strong underground continuous wall in which slag, cement, and soil in which slag and excavated earth and sand that serve as aggregates are integrated is formed. The slag, cement, and soil formed in this way increase the long-term strength by hardening the slag, compared to the so-called soil cement, which is a hardened monolithic product of the conventional cement and the soil that is the excavated earth and sand of the ground. And also
The presence of excavated earth and sand as an aggregate increases the strength as compared to a slag grout that has only been hardened by adding a calcium component such as cement, and as a result, underground continuous walls of conventional soil cement and An underground continuous wall having a higher strength can be formed as compared to an underground continuous wall obtained by curing slag grout, and since the mixing adjustment of the second mixture B is performed on the ground, a uniform underground continuous wall can be formed. It can be formed.
In addition, the amount of cement used in mixing and adjusting the second mixture B on the ground can be reduced by the amount of slag grout used, and the cost can be reduced accordingly.

By the way, when the second mixture B is returned into the groove 3 on the rear side of the partition 17, the second mixture B is discharged into the groove 3 by the transport pipe 5 and returned. 3 can be reliably filled with the second mixture B. Next, another embodiment of the present invention will be described with reference to FIGS.
A description will be given based on FIG. In the embodiment shown in FIGS. 4 and 5, the discharge pipe 30 is inserted into the groove 3, and the discharge pipe 30 is used to fill the space ahead of the partition 17 of the groove 3 by suction means such as a pump. The first mixture A in which slag grout and excavated earth and sand are mixed is sucked up and discharged to the ground. That is, the discharge pipe 30 provided with the suction means is the discharge means 16. By using the excavating means 2 and the discharging means 16 as separate members as described above, the excavating means 2 does not need to be formed in a bucket shape as in the above-described embodiment, and the excavating means 2 can be formed in a form other than the bucket shape. It is. In this embodiment, the discharge pipe 30
May be supported by the frame main body 9, or may be supported by the front side of the partition 17.

In each of the above embodiments, the example in which the sieving means 4 and the adjusting device 21 are provided on the base machine 7 is shown. However, these are not installed on the base machine 7 but installed on the ground and connected by a hose. You may connect.

[0024]

Example: Slag grout, cement and soil were mixed
Using the second mixture B of the present invention as an example, cement milk
Conventional soil cement mixed with soil and soil as a comparative example
A uniaxial compressive strength test was performed for each material age. (1). Materials used Normal Portland cement (specific gravity 3.15), slag
(Specific gravity 2.89), bentonite (specific gravity 2.6), water,
Soil (sand, water content 6.39%, r = 1.80 t / m ^Three )
Using.

(2). Formulation Formulation is as shown in Table 1 below.

[0026]

[Table 1]

FIG. 6 shows the results of determining the uniaxial compression test strength by material age of the examples of the present invention having the above composition and the comparative examples.
As is clear from FIG. 6, it is clear that the embodiment of the present invention is superior in uniaxial compressive strength to the conventional soil cement in which cement milk and soil are mixed.

[0028]

According to the first aspect of the present invention, when constructing a vertical continuous underground wall having a constant width in the ground, the excavator inserted into the ground is moved laterally. With
A first mixture in which the slag grout is excavated into the ground in a lateral traveling direction ahead of a partition provided in the excavator while a groove is excavated by excavation means provided in the excavator, and the slag grout and excavated earth and sand are mixed; Is discharged to the ground, and the first mixture discharged to the ground is mixed with a cement component to obtain a second mixture, which is placed in a groove on the rear side of the partition in the lateral traveling direction of the excavator.
Because the second mixture is returned, it is before the partition in the transverse direction.
Since excavation is performed in the lateral direction while discharging slag grout into the ground, lateral excavation can be easily performed, and a mixture of slag grout and excavated earth and sand is located in front of the excavated partition . Since the first mixture is filled, it is possible to prevent the side wall of the groove from collapsing,
Further, the second mixture prepared on the ground is placed behind the partition.
By returning the excavated earth and sand in the original ground to the aggregate, it is possible to form an underground continuous wall of uniform strength by returning the excavated soil into the part of the groove. Moreover, since the first mixture is a mixture of slag grout and excavated earth and sand, the slag does not start to harden before it is not mixed with the cement, and even if it is discharged to the ground, hardening has not started. In addition, because it can prevent pipes from clogging, and because not only cement but also slag is used as a hardening material, the amount of cement used is reduced and costs are reduced,
The finally formed underground continuous wall is an integrated material of slag, cement and soil and has high strength. Furthermore,
Excavation of excavated trench by excavator
Partitioning in the lateral direction of the excavator,
Since the second mixture is returned into the groove on the rear side of the cut,
Mixing of slag grout in the trench ahead of
Fill into the groove behind the partition on the combined first mixture side
To prevent the inflow of the cement component of the second mixture
As a result, the hardening of the slag of the first mixture is started.
Slag in the groove before the partition
The excavation can be performed easily without impairing the flowability of the
It can be easily discharged.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, the first mixture discharged to the ground is sieved by sieving means to remove the first mixture from the excavated earth and sand. Since the large particles are removed, and the cement component is then mixed to obtain a second mixture, and the second mixture is returned to the groove, the aggregate is obtained even though the excavated sediment of the original ground is used as the aggregate. Of the second mixture to be adjusted and mixed can be uniform, and the clogging of the piping can be prevented.

[0030]

According to the third aspect of the present invention, in addition to the effects of the first or second aspect, the second mixture formed on the ground is discharged into the inside of the groove by the transport pipe. Since the second mixture is returned, the second mixture can be surely returned and filled even if the groove is deep.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an embodiment of the present invention during construction.

FIG. 2 is a plan sectional view of the same.

FIG. 3 is an operation explanatory view showing an example in which the first mixture is discharged to the ground.

FIG. 4 is a schematic longitudinal sectional view of another embodiment of the present invention during construction.

FIG. 5 is a plan sectional view of the same.

FIG. 6 is a graph showing the uniaxial compressive strength of an example of the present invention and a comparative example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 excavator 2 excavating means 3 groove 4 sieving means 5 transfer pipe 17 partition A first mixture B second mixture

Claims (3)

(57) [Claims] When constructing a vertical underground continuous wall having a constant width in the ground, an excavator inserted into the ground is moved in a lateral direction, and the excavator is moved in front of a partition provided in the excavator in a lateral traveling direction.
While discharging the slag grout into the ground, a trench is excavated by the excavating means provided in the excavator, the first mixture of the slag grout and the excavated earth and sand is discharged to the ground, and the first discharged to the ground is discharged. The second mixture is obtained by mixing the cement component with the mixture of the above, and the second mixture is provided behind the partition in the lateral traveling direction of the excavator.
A slag-graft-based circulating underground wall method , comprising returning the second mixture into the side groove . 2. The first mixture discharged on the ground is sieved by sieving means to remove large particles in the excavated earth and sand, and then the cement component is mixed to obtain a second mixture. The method according to claim 1, wherein the mixture of (2) is returned to the groove. 3. A second mixture slag graft system circulating underground wall construction method according to claim 1 or claim 2, wherein the return discharges into the groove by the transport tube of which is formed on the ground.