JP5810018B2 - Ground improvement method - Google Patents

Description

  The present invention relates to a ground improvement method.

Conventionally, a method of creating a ground improvement body by a high-pressure jet stirring method in order to stabilize the foundation ground or the like is known (see, for example, Patent Document 1).
In such a high-pressure jet agitation method, for example, an injection nozzle is inserted into the ground, and an ultra-high pressure hardened material and compressed air are press-fitted and injected from the injection nozzle at the tip of the injection pipe into the ground. This is a ground improvement method in which the ground around the area is cut and the injected hardened material and the cut earth and sand are mixed to improve the ground in that area.

JP 2007-77739 A

However, the conventional ground improvement methods have the following problems.
That is, for example, in the construction of an existing blast furnace installed at an ironworks to expand the blast furnace volume, ground improvement is performed to increase the foundation strength of the ground directly under the existing blast furnace foundation to a strength corresponding to the blast furnace volume. May be. In this case, in the conventional high-pressure jet agitation method, a work space that communicates from the outside of the plan view of the blast furnace foundation to the lower side of the foundation is provided, and the injection pipe is inserted into a predetermined position using the work space. Since the work is performed in a small work space, it takes time and it is necessary to occupy the ground part on the foundation until the improvement work is completed. Moreover, since the operation of inserting the injection tube becomes more difficult as the center side of the blast furnace foundation is viewed in plan, there is a problem that work efficiency is lowered.
Furthermore, in the case of the existing blast furnace as described above, it is required to shorten the blast furnace stoppage period and to operate the blast furnace as much as possible even during the ground improvement period. There was room for improvement.

  The present invention has been made in view of the above-mentioned problems, can improve work efficiency, can perform ground improvement work in parallel with the operation of existing facilities, and can shorten the work period for ground improvement. An object is to provide a method for improving ground.

In order to achieve the above object, in the ground improvement method according to the present invention, the main body part and the lower part of the main body part have an enlarged part expanded in the radial direction, and the existing equipment foundation supported from below by a number of existing piles. the ground between existing piles each other immediately below and ground improvement by high-pressure injection mixing method, a soil improvement method for solidifying the ground, in the enlarged portion of the existing equipment foundation, in the vertical direction between the existing pile in a plan view A first step of drilling and penetrating to provide a through hole, a second step of inserting the injection pipe into the ground to be improved below the existing equipment foundation while inserting the injection pipe through the through hole, and the injection pipe And a third step of creating a ground improvement body by high-pressure injection of the improvement material into the ground from the tip, wherein the first step to the third step are performed in parallel with the operation of the existing equipment. .

  In the present invention, the through hole for inserting the injection hole penetrating in the vertical direction in the existing equipment foundation is drilled, and the injection pipe is inserted into the ground under the existing equipment foundation using the through hole, and improved from the tip of the injection pipe. A ground improvement body can be created by performing high-pressure jet agitation in which a high-pressure jet of material is injected into the ground. Therefore, it is not necessary to provide a work space that communicates from the outside of the existing equipment foundation to the lower part of the existing equipment foundation as in the past, and work in a narrow work space is possible, so that work efficiency can be improved. The construction period for ground improvement work can be shortened, and further, the overall construction period required for remodeling existing facilities can be shortened.

  In addition, in the ground improvement method of the present invention, since the ground improvement device is simply arranged on the ground part, even when the injection pipe is inserted into the ground, even when the ground improvement is in progress, the vicinity of the existing equipment foundation. It is possible to easily move the ground improvement device by interrupting the ground improvement work as appropriate in accordance with the operating status of the operating vehicle traveling on the ground. Therefore, it is possible to prevent the running of the operating vehicle from being obstructed along with the ground improvement work as in the case where the work space is provided below the existing equipment foundation, and it is possible to prevent the existing equipment from being stopped for a long period of time. The ground improvement body can be created directly under the existing equipment foundation while operating the existing equipment. In addition, the ground improvement work should be performed while interrupting the ground improvement work according to the work on the existing equipment on the ground and moving the ground improvement device, while suppressing the impact on the operation of the existing equipment. Can do.

  Moreover, in the ground improvement method according to the present invention, it is preferable to improve the ground on the inner part surrounded by the outer periphery improvement body after improving the ground in advance in the plan view in the ground to be improved.

  In this case, the improvement target ground is improved by leading the outer peripheral portion in plan view, and therefore the ground in the range of the inner portion surrounded by the outer peripheral improvement body formed on the outer peripheral portion is restrained. Therefore, it is possible to prevent the slime generated by the high-pressure injection from blowing out to the ground on the ground of the inner part and the outer ground of the outer peripheral improvement body, and the traveling of the operation vehicle on the ground is prevented by the sprayed slime. Can be prevented.

  Further, in the ground improvement method according to the present invention, when a concrete roadbed is provided as a work floor on an existing equipment foundation, the outermost peripheral part in a plan view of the existing equipment foundation and an operating vehicle that travels during the operation of the existing equipment It is more preferable that the concrete roadbed between the traveling track is provided with a guide hole for guiding and pulling out slime generated by high pressure injection.

By adopting such a configuration, it is possible to discharge the slime produced in connection with the construction of the constructed high-pressure jet from the induction hole, for example, to suck the slime toward the induction hole by sucking from the induction hole. The slime can be forcibly sucked and pulled out.
And in the plan view of the existing equipment foundation, a guide hole is provided at an arbitrary position between the outermost peripheral part and the running track of the operating vehicle that runs during the operation of the existing equipment, and the slime can be collected at that position. Therefore, it is possible to prevent the slime from moving along the lower surface of the concrete roadbed and ejecting in the vicinity of the running track, and to prevent the problem of hindering the running of the operating vehicle on the running track.

  Further, in the ground improvement method according to the present invention, it is more preferable to fill the solidified material through the through hole into the gap formed between the lower surface of the existing equipment foundation and the ground improvement body after the ground improvement body is created. .

  Thereby, even when a gap is formed between the created ground improvement body and the existing equipment foundation, the gap can be filled with a solidifying material such as mortar, and the solidified material is solidified. Thus, the force acting on the existing equipment foundation can be reliably transmitted to the ground.

According to the ground improvement method of the present invention, since the ground improvement body can be created directly below the existing equipment foundation using the through-hole provided in the existing equipment foundation, the work efficiency can be improved.
And, for example, it becomes possible to eliminate the area that occupies the ground part over the entire work period for ground improvement, such as a work space that communicates below the existing equipment foundation, and the ground improvement work can be performed in parallel with the operation of the existing equipment. Since it is possible to shorten the construction period for ground improvement, rational reinforcement can be realized in the existing equipment foundation.

It is a longitudinal section showing a ground improvement object by an embodiment of the invention. It is a top view of the ground improvement body shown in FIG. (A)-(c) is a figure for demonstrating the process of ground improvement. (A)-(c) is a figure for demonstrating the process of the ground improvement following FIG.3 (c). (A)-(c) is a figure for demonstrating the process of the ground improvement following FIG.4 (c). It is a side view which shows the slime drawing state using the induction hole. It is a top view of the slime drawing state shown in FIG.

  Hereinafter, a ground improvement method according to an embodiment of the present invention will be described with reference to the drawings, taking a ground improvement method in a blast furnace of an ironworks as an example.

  As shown in FIGS. 1 and 2, the ground improvement method according to the present embodiment shows an example in the case of expanding the volume of an existing blast furnace by, for example, renovation work of a blast furnace at a steelworks, and the blast furnace foundation 1 ( In order to increase the foundation strength of the ground G directly under the existing equipment foundation), a ground improvement body K is created by applying a high-pressure jet stirring method.

  Here, the blast furnace foundation 1 has a main body portion 1A and an enlarged portion 1B in which a lower portion of the main body portion 1A is enlarged in a radial direction (a direction orthogonal to the vertical direction). It is buried inside. In addition, a construction space R having a ceiling 11 is provided on the ground surface Ga as shown in FIG. The height dimension of the construction space R is, for example, about 3 m.

The improvement range (target ground G ′) according to the present embodiment, that is, the position of the ground improvement body K is within the range immediately below the enlarged portion 1B of the blast furnace foundation 1, as shown in FIGS. The depth is, for example, a range of sandy soil G1 near the ground surface. In other words, the portion directly below the main body portion 1A located at the radial center portion of the enlarged portion 1B is outside the range of the ground improvement body K. In addition, this improvement depth can be suitably set according to the state of the stratum directly under the blast furnace foundation 1.
And the blast furnace foundation 1 is supported from the downward direction by many existing piles 2, 2, ..., and the ground improvement body K is created using the area | region between these existing piles 2. FIG.

Next, the ground improvement method will be described in more detail based on the drawings.
As shown in FIGS. 3 to 5, the ground improvement body K is constructed by applying the rod 33 (injection pipe) of the ground improvement apparatus 3 to the target ground G by the high-pressure jet stirring method during the operation of the existing equipment (blast furnace). The rod 33 shown in FIG. 4 is inserted into the target ground G ′ between the existing piles 2 and 2 embedded in the bottom of the enlarged portion 1B of the blast furnace foundation 1. Cement milk (improvement material) is jetted from the rod tip 33a (tip of the injection pipe) toward the improvement target ground G ′, and the improvement target ground G ′ is stirred and mixed to solidify to form a ground improvement body K. ing. Thereby, the vertical bearing force and horizontal rigidity of the existing pile 2 can be increased, and the load resistance can be improved.

  First, as shown to Fig.3 (a), in the construction space R on the enlarged part 1B of the blast furnace foundation 1, the enlarged part 1B is drilled up and down, and the through-hole 12 is provided. That is, a plurality of bores having an outer diameter of φ300 mm, for example, reaching the upper surface of the enlarged portion 1B of the blast furnace foundation 1 are performed at predetermined positions, and the steel pipe 4 having a smaller diameter than the borehole is built. At this time, the steel pipe 4 is filled with mortar and filled with holes. Then, the through-hole 12 is provided by drilling the enlarged portion 1B of the blast furnace foundation 1 from the steel pipe 4 in the vertical direction. In addition, using these through-holes 12, for example, a ground survey is performed at a rate of about 1 in 15 to 20, and the support layer (the improvement target ground G ') is confirmed.

  Next, as shown in FIG. 3 (b), the ground improvement device 3 is installed in the construction space R, and the casing 31 provided with the drilling bit 32 at the tip (lower end) is subjected to rotation and cutting according to soil conditions. The hole is drilled to the construction depth by the hole speed and inserted into the improvement target ground G ′.

Thereafter, as shown in FIG. 3C, a rod 33 made of a double pipe for cement high pressure injection is built in the casing 31 and the casing 31 is pulled out. In some cases, the casing 31 may be left.
Here, when the rod 33 shown in FIG. 3C is built, as shown in FIG. 4A, a pre-jet work is applied to the viscous ground. Specifically, ultra-high pressure injection with fresh water is performed only on the ground G ′ to be improved, and the ground is discharged, and the slime at this time is discharged by a sand pump or the like (not shown) installed in the construction space R on the ground. To do.

Next, as shown in FIG. 4B, a ground improvement body K is created by high-pressure jet stirring. In this case, a substantially cylindrical ground improvement body K is formed on the improvement target ground G ′ by lifting the rod 33 while injecting the improvement material from the rod tip 33a. The discharged slime is sucked up by the same sand pump (not shown) as described above. Then, as shown in FIG. 4C, after the formation of the ground improvement body K is completed, the inside of the through hole 12 is washed while the rod 33 is pulled out to the ground.
In FIGS. 4 and 5, the diameter of the ground improvement body K is increased for easy viewing.

  Next, as shown in FIG. 5A, high-pressure water is supplied from the filling rod 5 inserted through the through hole 12 through the top Ka of the formed ground improvement body K and the lower surface 1b of the enlarged portion 1B of the blast furnace base 1. Spray to clean. Thereafter, as shown in FIGS. 5 (b) and 5 (c), the non-shrinkable filler P (solidified material) is filled from the filling rod 5 toward the lower space S of the blast furnace foundation 1, and the through holes 12 and The steel tube 4 is filled with the non-shrinkable filler P while the filling rod 5 is pulled out, and the construction is completed.

Next, a method for forcibly recovering slime generated with high-pressure jet stirring will be described.
As shown in FIGS. 6 and 7, a running track 7 for running a torpedo car 6 (operating vehicle) is laid on the ground portion outside the ground improvement body K to be formed, and during operation of the blast furnace. The torpedo car 6 regularly travels on the travel line 7. Here, a concrete roadbed 8 is provided on the ground above the enlarged portion 1B of the blast furnace foundation 1 to ensure workability as a work floor.
And in the plan view in the enlarged part 1B of the blast furnace foundation 1, the outermost peripheral part 1a and the concrete roadbed 8 of the torpedo car 6 that travels during the operation of the blast furnace are subjected to slime M generated by high-pressure injection. A guide hole 9 for guiding and pulling out is provided.

In this case, the slime M generated in connection with the applied high-pressure injection can be discharged from the induction hole 9. For example, the slime M is sucked from the induction hole 9 by a suction device (vacuum) (not shown). The slime M can be forcibly sucked and pulled out. The arrows in FIGS. 6 and 7 indicate the direction in which the slime M is guided and moved.
A guide hole 9 is provided at an arbitrary position between the outermost peripheral portion 1a in plan view of the blast furnace foundation 1 and the traveling line 7 of the torpedo car 6 that travels during operation of the blast furnace, and the slime M is collected at that position. Therefore, it is possible to prevent the slime M from moving along the lower surface 8a of the concrete roadbed 8 and ejecting in the vicinity of the traveling track 7, and preventing the trouble that the traveling of the torpedo car 6 on the traveling track 7 is obstructed. can do.

Next, the effect | action by implementing the ground improvement method mentioned above is demonstrated.
In this ground improvement method, as shown in FIGS. 3 to 5, a rod insertion through-hole 12 penetrating vertically in the enlarged portion 1 </ b> B of the blast furnace foundation 1 is drilled, and the rod 3 is used by using this through-hole 12. Is inserted into the ground below the blast furnace foundation 1, and the ground improvement body K can be created by performing high-pressure jet agitation in which the non-shrinkable filler P is injected into the improvement target ground G 'from the rod tip 33a.
Therefore, it is not necessary to provide a work space that communicates from the outside of the blast furnace foundation 1 to the lower side of the blast furnace foundation 1 as in the prior art, and work in a narrow work space is possible, so that work efficiency can be improved. The construction period for ground improvement work can be shortened, and further, the construction period for repairing the blast furnace can be shortened.

  In addition, since the ground improvement device 3 is simply arranged on the ground part, the ground part on the blast furnace foundation 1 (in this case, the construction space) even during the ground improvement with the rod 33 inserted into the ground. According to the operating situation of the torpedo car 6 (see FIGS. 6 and 7) traveling on R), the ground improvement device 3 can be easily moved by interrupting the ground improvement work as appropriate. Therefore, it is possible to prevent the torpedo car 6 from being obstructed by the ground improvement work as in the case where the work space is provided below the blast furnace foundation 1, and there is an advantage that it is not necessary to stop the blast furnace for a long time. Yes, the ground improvement body K can be created directly under the blast furnace foundation 1 while operating the blast furnace. In addition, it is possible to perform ground improvement work while suppressing the influence on the operation of the blast furnace by interrupting the ground improvement work and moving the ground improvement device 3 as appropriate according to the work on the blast furnace on the ground. it can.

Moreover, in this ground improvement method, as shown in FIG. 2, after improving the ground in advance in the plan view in the ground G ′ to be improved, the inner portion surrounded by the outer peripheral improvement body K1 (reference numeral K2 ) Is preferably a procedure for ground improvement.
In this case, in the improvement target ground G ′, the outer peripheral improvement body K1 is improved in advance, so that the ground in the range of the inner portion K2 surrounded by the outer peripheral improvement body K1 is restrained. Therefore, it is possible to prevent the slime generated by the high-pressure injection from blowing out to the ground on the ground of the inner portion K2 and the ground outside the outer peripheral improvement body K1, and as shown in FIG. 6 and FIG. It is possible to prevent M from obstructing the traveling of the torpedo car 6 on the ground. In FIG. 2, a line indicated by a broken line indicates a boundary between the outer peripheral improvement body K1 and the inner portion K2.

  Further, as shown in FIGS. 5 (a) to 5 (c), even when the void S is formed between the ground improvement body K and the blast furnace base 1, the non-shrinkage filling of the void S is performed. The material P can be filled, and the force acting on the blast furnace foundation 1 can be reliably transmitted to the ground by solidifying the non-shrinkable filler P.

  Furthermore, since the space of the through-hole 12 drilled for the purpose of ground improvement is also filled with the non-shrinkable filler P, the strength reduction of the blast furnace foundation 1 itself can be suppressed, and the blast furnace foundation 1 and the ground improvement body K can be suppressed. The unity with can be improved.

  In the ground improvement method according to the present embodiment, the number of through holes 12 to be opened, that is, the ratio of the voids of the through holes 12 to the blast furnace foundation 1 is, for example, a ratio of about 10% of the entire volume of the blast furnace foundation 1. Therefore, even when the reinforcing bar of the blast furnace foundation 1 is cut when the through-hole 12 is drilled, the strength of the foundation itself is not greatly reduced.

In the ground improvement method according to this embodiment described above, the ground improvement body K can be created directly below the blast furnace foundation 1 using the through-holes 12 provided in the blast furnace foundation 1, so that the work efficiency is improved. be able to.
And since it becomes possible to eliminate the area | region which occupies the ground part over the whole work period concerning ground improvement, such as the work space connected below the blast furnace foundation 1, for example, the ground improvement work is performed in parallel with the operation of the blast furnace. Since it is possible to shorten the construction period for ground improvement, it is possible to achieve rational reinforcement in the blast furnace foundation 1.

As mentioned above, although embodiment of the ground improvement method by this invention was described, this invention is not limited to said embodiment, It can change suitably in the range which does not deviate from the meaning.
For example, in the above-described embodiment, the ground improvement of the outer periphery improvement body K1 in the plan view in the improvement target ground G ′ is performed first, and then the inner portion K2 surrounded by the outer periphery improvement body K1 is improved. However, it is not limited to such a procedure, and can be appropriately set based on the shape of the blast furnace foundation 1, the geological conditions, the placement of the torpedo car on the ground, the operating state of the blast furnace, and the like.

Moreover, in this Embodiment, although the blast furnace (blast furnace foundation 1) was made into an example as existing equipment (existing equipment foundation), it is not limited to being a blast furnace (blast furnace foundation), and the building ( Building foundations) can be used for existing equipment. In addition, it is not restricted to the existing facilities of a steelworks.
Furthermore, although the torpedo car 6 is taken as an example of the operating vehicle in the present embodiment, the present invention is not limited to this, and may be an operating vehicle that transports, for example, a high-temperature, heavy load.

  Moreover, the range of the ground improvement body K created directly under the blast furnace foundation 1, the number of inserted rods 33 (the number of improvements), the position, the interval, the depth, and the like are not particularly limited and can be changed as appropriate.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

1 Blast furnace foundation (existing equipment foundation)
1A Main body 1B Enlarged part 2 Existing pile 3 Ground improvement device 4 Steel pipe 5 Filling rod 6 Torpedo car (operating vehicle)
7 Traveling track 8 Concrete roadbed 9 Guide hole 12 Through hole 31 Casing 32 Drilling bit 33 Rod (injection pipe)
33a Rod tip (infusion tube tip)
G Ground G 'Improvement target ground K Ground improvement body M Slime P Non-shrinkable filler (solidification material)
S gap

Claims (4)

The main body part and the lower part of the main body part have an enlarged part expanded in the radial direction, and the ground between the existing piles immediately below the existing facility foundation supported by a number of existing piles from below is obtained by a high pressure jet agitation method. A ground improvement method for improving the ground and solidifying the ground,
In the enlarged portion of the existing equipment foundation, a first step of providing a through hole by drilling and penetrating between the existing piles in a vertical direction in plan view ;
A second step of inserting the injection tube into the ground to be improved below the existing equipment foundation while inserting the injection tube through the through hole;
A third step of creating a ground improvement body by high-pressure injection of the improvement material into the ground from the tip of the injection pipe;
Have
The first to third steps are performed in parallel with the operation of the existing equipment.   2. The ground improvement method according to claim 1, wherein the ground improvement is performed on the inner portion surrounded by the outer periphery improvement body after the outer periphery portion is improved in advance in a plan view in the improvement target ground. In the case where a concrete roadbed is provided as a work floor on the existing equipment foundation,
In the concrete roadbed between the outermost periphery in plan view of the existing equipment foundation and the running track of the operating vehicle that runs during the operation of the existing equipment, a guide hole for guiding and pulling out slime generated by high-pressure injection The ground improvement method according to claim 1, wherein the ground improvement method is provided.   The solidified material is filled through the through hole into a gap formed between the lower surface of the existing equipment foundation and the ground improvement body after the ground improvement body is created. The ground improvement method according to any one of the above.

Images