JPH02221512A - Method and apparatus for modifying weak ground - Google Patents

Abstract

PURPOSE:To prevent pollution and treat with high accuracy by a method wherein with a rod rotated in weak ground to stir and supply residual soil from under excluded soil while a solidifying agent is supplied from a solidifying agent outlet to be stirred with residual soil to accelerate solidification. CONSTITUTION:At the tip of a inner and outer double structured cylindrical rod 2' which relatively rotates, mixing and stirring blades 4 are provided in two stages of upper and lower along a diameter with a hole drilling pit 3. Then an auger 5 having a smaller diameter than the mixing and stirring blades 4 is fixed from a base of a shank of the rod 2' to a specific position while a driving mechanism 6 is provided at the base. Then a hole of specific depth is drilled into the weak ground by rotating the mixing and stirring blades 4 via the rotation of the rod 2' while the auger 5 is rotated to exclude part of the soil to the ground surface. While stirring the residual soil under the excluded soil, solidifying agent such as cement milk is sprayed from a solidifying agent outlet 9 to form a solidified column of soil cement or the like.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology is used to construct structures such as buildings on soft ground such as coastal reclaimed land in advance so that the soft ground has sufficient strength. It belongs to the technical field of ground improvement.

Summary of the gist> The invention of this application supplies a solidifying agent such as cement milk into soft ground near the coast, lakes, rivers, etc. by spouting it, and the soil in the soft ground and the like. This invention relates to a method for improving soft ground in which a solidified column is formed to have a predetermined strength by mixing and stirring, and a device directly used in the method, and in particular, it relates to a solidifying agent such as cement milk that is supplied into the ground. After drilling a hole in the soft ground by an amount equivalent to the supply wall, a small diameter soil column is discharged to the ground surface concentrically with respect to the hole, or a predetermined hole with the same diameter as the hole above the hole is excavated. In addition to removing the soil at the top of the hole, a predetermined amount of soil around the top of the hole is also removed, and the solidification material is mixed and stirred with the remaining soil in the hole loosened by the hole drilling. A method for improving soft ground in which treatment is carried out so that solidified columns are formed smoothly, and a device directly used in the method, in which a mixing agitation blade in the diametrical direction etc. is provided at the tip of the rod,
An invention relating to a soft ground improvement device in which an auger is installed in the upper part of the hole to remove and remove the soil at the top of the hole to the surface of the predetermined leased land, and mix and stir the soil left over from the hole being drilled with a solidification material. It is.

<Prior art> As is well known, the effective use of national land is an extremely important issue in our country, which has a limited land area.For example, in order to become an industrialized nation, we have been trying to build structures such as various manufacturing factories horizontally. Although there is an extremely large demand for land to be used for construction and construction of various facilities, there is always a shortage of usable land that can be supplied. It is undesirable because it leads to the loss of resources and the destruction of the natural environment, and it also has a large impact on water resources and causes pollution problems, etc., and there are limits. So-called soft ground improvement, which improves the soft ground around rivers, lakes, etc., into ground with sufficient strength has been attracting attention for a long time, and various ground improvement techniques have been developed and some have been effectively put into practical use. be.

For example, the sand drain method is a flat-type method for improving soft ground, but it requires a specific type of sand as a material, requires embankment as an overloading load, and has the inconvenience of not being able to improve high strength. .

To deal with this, soft ground improvement technology has been developed that uses a solidifying agent such as a cement slurry or cement milk to be sprayed into the ground.There is also a so-called sand compaction method, which has less impact on surrounding areas and can be constructed at ultra-deep depths. Although it has become widely used due to its advantages such as ease of use, it also requires sand as a material, and has the disadvantage that it generates vibrations that have a large impact on the surrounding area and cannot improve its strength.

<Problem to be solved by the invention> However, in the conventional method for improving soft ground by supplying such a solidifying agent into the soft ground, the soil in the ground is reduced by the amount of the solidifying agent such as cement milk supplied into the ground. Since the soil overflows to the ground surface mixed with solidification materials such as cement milk, the mixture of soil and solidification materials must be post-processed, and as a type of industrial waste treatment, it causes pollution such as contaminating the surrounding area. In terms of capacity, it was necessary to provide a treatment plant with sufficient volume and space, which often resulted in problems that could not be dealt with in terms of facilities, and the disadvantages were that they tended to lead to higher costs.

In addition, when a borehole is formed in the ground and the soil in the borehole is mixed and stirred, the mixture of the soil in the borehole and the solidification agent such as cement milk is mixed into the borehole. This has the drawback that a so-called co-rotation phenomenon occurs, making it impossible to perform highly accurate and reliable mixing and agitation, and as a result, highly reliable ground improvement cannot be performed.

<Object of the Invention> The object of the invention of this application is to develop cement l based on the above-mentioned prior art.
- The problem of ground improvement by mixing and stirring a solidifying agent such as milk with soil on soft ground is considered a technical problem to be solved, and the advantages of improving soft ground by supplying a solidifying agent such as cement milk into the ground are discussed. An excellent soft ground improvement method that benefits the field of application of mixing and agitation technology in the construction industry by allowing highly accurate ground improvement as designed without causing pollution problems while being fully utilized; and The purpose is to provide an apparatus for direct use in the method.

In order to solve the above-mentioned problems, the structure of the invention of this application, which is based on the above-mentioned claims, is to solve the above-mentioned problems. When carrying out ground improvement work on soft ground to provide a predetermined strength, a hole is drilled into the soft ground to a predetermined depth by rotating a mixing agitation blade at the tip of the rod. After the hole is reached, the auger previously formed on the upper part of the rod is rotated, or the rod is rotated at low speed or stopped and then pulled up, allowing the auger to move concentrically during drilling. Either, depending on the diameter of the auger, a predetermined amount of soil at the top of the excavation hole is removed to the ground surface, and the rod is rotated accordingly to remove the removed soil from below. Instead of stirring the removed residual soil, a specified solid material is jetted out from a solidification material spout provided at a specified part of the rod, mixed with the residual soil and stirred to promote an assimilation reaction, thereby forming soil cement 1 to 1 over time. During construction, an outer cylinder with a baffle plate inside to prevent co-rotation is provided at the tip of the rod, and a mixing stirring blade is used to clean the inside of the nuclear outer cylinder. Mix and stir the soil and solidification material, or a mixture thereof, to prevent these materials from rotating together to ensure mixing and stirring to form a solidification column, or Instead, a predetermined frame is formed on the outside of the mixing and stirring blade, and relative rotation is performed in the opposite direction to the mixing and stirring blade or at a different rotational speed, so that mixing and stirring can be efficiently performed together with the mixing and stirring blade, etc. inside the frame. It took technical measures to facilitate assimilation by ensuring that

<Embodiments> Next, embodiments of the invention of this application will be described below with reference to the drawings.

The embodiment shown in FIG. 1 is an embodiment of the basic soft ground improvement device 1 of the invention of this application, in which a hole-drilling bit 3 is attached to the tip of a cylindrical rod 2' of the 2@type inside and outside that rotates relative to each other. is provided with a pair of mixing and stirring blades 4 in the diametrical direction at its base.
, 4 are fixedly installed in upper and lower two stages, and an auger 5 having a smaller diameter than the mixing stirring blade 4 is fixedly installed from the base end of the shank of the rod 2' to a predetermined part, and the auger 5 has a smaller diameter than the mixing stirring blade 4. The soil is removed to the ground by pulling up an auger 5, and a drive mechanism 6 such as a motor and a reduction gear is installed at the base.
A passage 8 for a solidifying material such as cement milk in the rod 2' is connected to an injection port 9 of the bit 3, and a swivel joint is provided at the base end of the rod 2' to supply the solidifying material through a hose 7'. 7 is connected.

In the embodiment shown in Figs. 1 and 2, the rod 2' has a small diameter, but in the embodiment shown in Fig. 3.4, the rod 2' has a small diameter.
A casing pipe 2 is provided on the outside of the auger 5.
The diameter of the auger 5 is interpolated so that the soil can be better removed, and the rod 2
' and the casing pipe 2 have separate drive mechanisms 6, 6', respectively.
is provided so that the rod 2' and the casing pipe 2 are rotated in the normal and reverse directions, or the auger 5 and the mixing agitator 914.4' are rotated independently of each other by applying rotation with a relative speed difference. The soil in the drilling hole relatively below the mixing and stirring blade 4' passes through the inside of the casing pipe 2 at the center of the mixing and stirring blade 4', passes through the inside of the casing pipe 2, and passes through the upper part. It is designed so that it can be discharged and removed from the opening 10 to the ground.

Further, in the embodiment shown in FIGS. 5 and 6, the rod 2' that rotationally drives the mixing stirring lug 4, 4' at the tip is made small in diameter and is a pipe-shaped rod 2' extending from the base end to a predetermined length. has an auger 5 and operates the auger 5 inside the casing pipe 2 outside the casing pipe 2.
A soil discharge port 11 is formed laterally in the upper part of the container.

Incidentally, as shown in FIG. 6, a bearing 12 is interposed between the rod 21 and the casing pipe 2.

Moreover, almost the same effect can be expected even if the partial auger 5 is used without the casing pipe 2 attached.

In each of the above-mentioned embodiments, the bit 3 at the tip of the rod was provided with a spout 9 for solidifying material such as cement milk, but as shown in FIG. An ejection nozzle 9' may be provided at the base of the mixing agitation blade 4 having a curved cross section and on the back side in the rotational direction.

In the V embodiment shown in FIG. 8, three stages of mixing and stirring blades 4, 4' and 4' are provided at the tip of the rod 2', and their outer edges partially overlap in the axial direction to form an outer cylinder 13. is arranged and is connected to the rod 2' by a bearing 12' so as to be freely rotatable relative to the rod 2'.
When the soil and the solidification material are mixed and stirred in the chamber 3, baffle plates 14, 14, etc. are provided in order to prevent these mixtures from rotating together, so that mixing and stirring can be carried out more reliably. This is an embodiment in which soil can be discharged from between the arms 15 of.

In the embodiment shown in FIG. 9, a pillow-shaped frame 13' is provided concentrically with the rod 2 in place of the outer cylinder 13 of the above-mentioned embodiment, and is supported via a bearing 12'. The baffle plate 14.14. ... are provided for the mixing and stirring blades 4, 41 to further promote mixing and stirring of the mixing and stirring blades 4, 4' and the solidification material such as soil and cement milk within the frame 13', and to prevent co-rotation. Soil frame 13' to prevent
In the hole 15, it rises relatively when penetrating into the ground.
This is an embodiment in which the earth is discharged to the ground from '', and there is essentially no fundamental difference in the operation and effect of the embodiment shown in FIG. 8 described above.

Next, the embodiment shown in Figs. 10, 11, and 12 is a combination of the embodiment shown in Fig. 3 and the embodiment shown in Fig. 8, in which the cylindrical rod 2' is It has an auger 5 from a predetermined part to the upper end and inside the casing pipe 2 on the outside! The rod 2' and the drum-type outer cylinder 13 are integrally connected and rotatable by arms 15, 15, 15..., and an upper part is provided between the arms 15, 15... A soil discharge port 16 to the ground is formed, and a baffle plate 1 on the inner wall surface of the outer cylinder 13 is formed.
4.14 is located between the mixing and stirring receptacles 4°4' and 4' to further promote the mixing and stirring effect, improve the improvement accuracy, and prevent the mixture from rotating together in the outer cylinder 13. This is an embodiment in which the soil flows relatively in the opposite direction, making it easier to discharge the soil to the ground.

That is, when penetrating into the ground, the drum type inner cylinder 13
The ±ill mixture passes through it and emerges from the ground.

Furthermore, since the invention of this application is based on pulling up and stirring, the solidifying material can be ejected from the upper part of the rod 2' of the middle tube shaft, and soil can be drawn in from above and discharged from below. This inner cylinder 13 serves as a so-called mixer chamber so that the soil and solidified (A) can be mixed well and discharged.

For these reasons, only the soil portion of the cross section of the auger 5 is discharged to the ground as surplus soil.

In the embodiment shown in FIGS. 13 and 14, a frame-shaped frame 131 is provided at the lower end of the casing pipe 2 so as to be rotatable integrally with the casing pipe 2, and the tip of the rod 2' inside the casing pipe 2 is In this case, a mixing and agitating blade 41 that rotates within the frame 13' is provided, and teeth 15, 15, . . . It is possible to improve the mixing and agitation efficiency.

In the embodiment shown in FIGS. 8 to 14, a kind of mixing and stirring section is formed inside the outer cylinder 13 and the frames 13' and 13'.

The basic principle of improving the soft ground to a predetermined set strength using each of the above-mentioned soft ground improvement devices will be explained with reference to FIG. 17, as shown in (a). As mentioned above, the soil 16 is left over by the amount of solidifying agent such as cement milk that is supplied to the soil 16 that has been loosened during drilling, and the surplus 17 is added to the remaining soil 1g1a as shown in (b). As shown in (c), the surplus 17 is previously separated and removed from the separated residual soil 18 as shown in 2) on the ground surface, and the same amount of cement milk as the removed part is added. As shown in (E), the solidifying material 19 of
Mix and stir with the remaining soil 18.
The method is to improve soft ground by solidifying the mixture 20 over time.As shown in Fig. 18, the concrete method is to drill a hole of a predetermined treatment diameter in the soft ground 21. A type of coring method is used to form a soil 22 with a predetermined small diameter concentric with the drilled hole 22 and remove the soil to the ground surface, and a solidification material such as cement milk is applied to the cored soil 23. 19 is supplied and mixed with the remaining soil and stirred, and as shown in FIG. I! ! An embodiment based on FIG. 5, in which 23' is replaced with a solidifying material, and the removed portion 23' is replaced with a solidifying material.
As shown in the figure, a predetermined amount of soil 23'' around the diameter of the borehole 22 and its outer circumference is removed as surplus at the upper part of the borehole 22, and the soil inside the borehole 22 is loosened. There is an embodiment in which the method shown in Fig. 5 is applied, in which the remaining soil and the solidification material are mixed and stirred to replace the removed remaining soil, and these embodiments can be achieved by using the soft ground improvement device of each of the above-mentioned embodiments. Alternatively, it can be achieved by combining them, and in order to perform the improvement mode shown in FIG. 19 using the soft ground improvement device shown in FIG.
As shown in the figure, the mixing agitation blade 4 of the soft ground improvement device set on the leader of heavy equipment (not shown) is connected to the soft ground 21.
The mixing stirring blade 4 is moved by the driving device 6 so as to face a predetermined portion of the mixing blade 4.
．． 4' is rotated to drill a hole to a set depth. In the process, the casing pipe 2' is penetrated from the surface of the soft ground 21 at a predetermined position, and the auger 5 descends from above.
is the drilling hole 22 formed by the mixing stirring fil 4, 4'
The loosened soil is discharged to the ground surface through the discharge port 11 in an amount equal to the amount of soil discharged in step 17, that is, an amount equal to the amount of solidifying material 19 such as cement milk that is spouted out in the subsequent process. While supplying a predetermined solidification material such as cement milk through the supply passage inside the rod 2', the mixing agitation blade 4,
By rotating the rod 4', and by lifting the rod 2M at a predetermined speed and handling it, the soil of the residual soil 18 and the solidification material 19 such as cement milk are mixed and stirred in the borehole 22. Over time, solidified pillars of soil cement are formed.

By doing this, the ground is improved in the area, and the soft ground in the predetermined area is improved by repeating the above process by moving the soil improvement device to a predetermined adjacent site.

Incidentally, it goes without saying that the embodiments of the invention of the eleventh application are not limited to the above-mentioned embodiments, and FIG.

The mode shown in Fig. 18 can be achieved by the soft ground improvement device shown in Fig. 10.
Those skilled in the art will easily understand that the earth removal and replacement method of the method shown in FIG. 19 or even FIG. 20 can be performed even if the casing pipe 2 shown in FIG. Various aspects can be adopted, such as a filter.

It goes without saying that other solidifying agents such as cement milk and cement slurry can also be used as the applicable solidifying agent.

<Effects of the Invention> As described above, according to the invention of this application, a solidification material such as cement milk is supplied into soft ground, and is mixed and stirred with the soil in the soft ground to form solidification pillars such as soil cement over time. In a method for improving soft ground to form a soft ground with a predetermined strength, a hole is formed in the soft ground, and the soil loosened during the drilling is supplied at the same time for solidification of cement milk, etc. An amount of waste soil equal to the amount of material supplied is discharged to the ground surface and removed, and a solidifying agent such as cement milk is supplied to the remaining soil during drilling by ejecting it, and mixed and agitated with a mixing agitation blade. By doing this, in the hole drilling process,
Due to the amount of solidification material supplied for mixing and stirring, the remaining soil in the drilling or the mixture with the solidification material will not overflow from the drilling to the ground surface, and therefore, the amount of industrial waste that will be disposed of will be reduced. This has the excellent effect of eliminating troublesome problems such as pollution and the accompanying pollution problems.

However, in order to remove and discharge a considerable amount of the solidified material supplied during drilling, it is necessary to treat soil with a smaller diameter than the drilling hole in the same way as with the coring method, remove the soil above the drilling hole, or remove the soil at the top of the drilling hole. Depending on the nature of the soft ground and the soft ground improvement equipment and method to be adopted, the choice is to discharge and remove the excavated soil and the surrounding soil to suit the amount of solidification material to be supplied. The effect of having a degree of design freedom that allows selection is also achieved.

Therefore, in the soft ground improvement device, an auger is provided on the top of the stirring blade provided at the tip of the rod, and a cap is used to core out and remove soil columns, etc. in the excavated hole. In this case, when removing and discharging the soil in the borehole at the set depth at the upper part, the auger discharges and removes the soil equivalent to the amount of solidification material supplied, and the mixing agitation blade precedes the auger and forms the borehole. Because the soil in soft ground is loosened in advance and can be discharged by the auger, depending on the design, the soil can be discharged and removed by pulling the auger in a stopped position without rotating the auger. There is an effect.

Further, by arranging the casing pipe outside the auger, there is also the effect that the soil equivalent to the supplied solidifying material can be more reliably discharged.

In addition, when installing an outer cylinder around the mixing and stirring blade, by providing a baffle plate, etc. for the mixing and stirring blade on the inner wall surface of the outer cylinder, the relative speed of the coughing outer cylinder can be increased or decreased relative to the mixing and stirring blade to a predetermined relative speed. By setting and stopping the outer cylinder, the outer cylinder is turned into a kind of mixing state, which not only has the effect of further promoting the mixing and agitation efficiency of the soil and solidification material by the mixing agitation blades, but also has the effect of further promoting the mixing and agitation efficiency of the soil and solidification material by the baffle plate. An excellent effect is achieved in that a solidified column is formed by highly accurate mixing and stirring as designed without the appearance of common surroundings.

Then, by forming a predetermined frame instead of the outer cylinder and providing an am or the like on the inner surface of the frame to perform a shearing action between it and the mixing agitation blade, the efficiency of the mixing agitation rate can be similarly improved, and the efficiency of the mixture can be improved. The effect is to prevent co-circulation and to perform highly accurate soft ground improvement.

[Brief explanation of the drawing]

The drawings show embodiments of the invention of this application, and
The figure is a schematic side view of one embodiment of a soft ground improvement device, Figure 2 is an enlarged sectional view of the same part, and Figure 3 is another example of soft ground improvement! A
A partially sectional side view of the embodiment of the present invention, FIG. 4 is similar to FIG.
tv sectional view, FIG. 5 is a partial sectional side view of another embodiment of the soft ground improvement device, FIG. 6 is an enlarged sectional view of the same part, and FIG.
The figure is a perspective view of the assembly of the bit, mixing agitation blade, and assimilation jet nozzle of a soft ground improvement device according to another embodiment, Nos. 8 and 9.
The figure is a partial cross-sectional side view of a stirring section of a soft ground improvement device according to yet another embodiment, FIG. 10 is an enlarged partial cross-sectional side view of a soft soil improvement device according to yet another embodiment, and FIG. XI
-X [Cross-sectional view, Figure 12 is a cutaway perspective view of the same part,
Figure 4 is a perspective view and partial cross-sectional side view of the stirring section of the soft ground improvement device of yet another embodiment, Figures 15 and 16 are partial cross-sectional side views of the soft ground improvement process, and Figures 178 (a) to ( g) is a schematic diagram explaining the basic principles of soft ground improvement, No. 18
Figures 20 to 20 are schematic cross-sectional views of the manner in which assimilated phase replacement soil is discharged and removed from a drilled hole. 2...Casing vibe 4.4'...Mixing stirring inner 13...Outer cylinder 14...Baffle plate 17...Soil 19...Solidification Material 22...Drilling hole 5...Auger 11...Earth removal port 13'...Frame 17...Earth removal 18... Remaining soil 21... Soft ground Figure 5 Figure 8

Claims (12)

[Claims] (1) In a soft ground improvement method in which a solidifying material is supplied into soft ground and mixed with the soil in the soft ground to form a solidified pillar, the soft ground is drilled to a predetermined depth. A method for improving soft ground, characterized in that a solidifying agent is supplied into the remaining soil in the hole and mixed and stirred before and after part of the soil in the hole is discharged to the ground surface. (2) The method for improving soft ground according to claim 1, wherein a portion of the soil to be removed is a soil column that is coaxial with the drilled hole and has a diameter smaller than the diameter of the drilled hole. (3) The method for improving soft ground according to claim 1, wherein a portion of the soil to be removed is upper soil having approximately the same diameter as the drilled hole. (4) The method for improving soft ground according to claim 1, wherein a portion of the soil to be removed is soil above the drilled hole and soil surrounding it. (5) In a soft ground improvement device that supplies a solidification material into soft ground, mixes it with the soil in the soft ground, and solidifies it, the mixing and stirring is applied to the tip of a drilling rod having a solidification material spout. A soft ground improvement device characterized in that a blade is provided and an auger is attached above the mixing and stirring blade. (6) The soft ground improvement device according to claim 5, wherein a casing pipe is attached to the outside of the auger. (7) The soft ground improvement device according to claim 6, wherein the casing pipe is rotatable. (8) The soft ground improvement device according to claim 6, wherein a soil discharge port is formed in the upper part of the casing pipe. (9) An auger is attached to the soft ground improvement device that supplies a solidifying material into the soft ground, mixes it with the soil in the soft ground, and solidifies it, and also has an auger attached to the outside of the mixing stirring blade to prevent co-rotation. A soft ground improvement device characterized by having an outer cylinder having a baffle plate. (10) The soft ground improvement device according to claim 9, wherein a rotating shaft is attached to the outer cylinder. (11) The soft ground improvement device according to claim 9, wherein the outer cylinder is enclosed in an auger. (12) An auger is attached to the soft ground improvement device that supplies a solidifying material into the soft ground, mixes it with the soil in the soft ground, and solidifies it, and a frame is further provided on the outside of the mixing and stirring blade. A soft ground improvement device characterized by having internal comb teeth.