JP4623482B2 - Solidification method using sleeve tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solidification method for soft ground.
[0002]
[Prior art]
Conventionally, various techniques exist for preventing liquefaction of soft ground.
For example, a boring hole is drilled perpendicularly to soft ground, and an injection method for injecting chemicals for ground improvement, or a filler that has a low fluidity and quickly solidifies to widen the soft ground, There is a filling grout method or the like in which aggregate or sand (filler) is filled and the soft ground is compacted.
[0003]
7 to 11 show examples of vertical excavation and grout injection by the so-called “sleeve injection method” of the conventional double pipe injection method. FIG. 7 to FIG. 10 show the construction sequence, and FIG. 11 shows the grout injection method. The mechanism of the sleeve injection method for this is shown.
[0004]
In FIG. 7, a sleeve tube 12 for filling a pre-drilled boring hole A8 with a seal grout Ms for preventing the collapse of the hole A8 and injecting an injection material (grout) into the unsolidified seal grout Ms is inserted. It shows the state being done.
[0005]
FIG. 8 shows a state in which the seal grout Ms in the bore hole A8 is solidified (HMs), and the injection material injection pipe 20 for injecting the injection material into the sleeve pipe 12 at a fixed position is inserted.
[0006]
As shown in FIG. 11, the injection material injection pipe 20 forms a gap 12 </ b> S in which a plurality of injection holes 23 provided on the pipe wall are packed with a plurality of rubber packers (generally called double packers) 21 on both sides, and the injection material Mg is It has a function of directing to the ground G. The injection material Mg sprayed from the inside of the sleeve tube 12 expands the rubber sleeve 14 from the injection nozzle 13 of the sleeve tube 12, and the solidified cement milk HMs is crushed (cracked) so as to penetrate into the ground G. It is configured.
[0007]
FIG. 12 is a side sectional view schematically showing the effect of the solidified cement milk HMs. In the upper part of the center line CC, solidified cement milk HMs of seal grout is formed between the enlarged diameter hole A8 and the sleeve tube 12, and in the lower part of the center line CC, the enlarged diameter hole A8 and the sleeve tube 12 are formed. Between the gaps is a gap AS.
In the upper part of the center line CC where the solidified cement milk HMs are present, the injected material Mg injected from the sleeve tube 12 pushes up the rubber sleeve 14 and goes out of the tube 12, and the solidified cement milk of the solidified layer is formed by the directivity of the injection. Cracks HMs and infiltrates ground G and plays a role in ground strengthening.
On the other hand, in the lower part of the center line CC without the solidified cement milk HMs, the injected material Mg injected from the sleeve tube 12 is more resistant than the osmotic pressure to the ground G even if it pushes up the rubber sleeve 14 and goes out of the tube 12. It escapes in the direction of few gaps AS and escapes as CMg and does not play the role of ground strengthening.
[0008]
FIG. 9 shows a state in which the pressurized water Wp is injected from the injection material injection pipe 20 inserted into the sleeve pipe 12, and the solidified cement milk HMs outside the rubber sleeve 14 is cracked to facilitate the injection of the injection material Mg. ing.
[0009]
FIG. 10 shows a state in which the grout Mg as an injection material is injected from the sleeve tube 12 into the ground G. A region where the injection material is solidified from the ground and solidified is HMg.
Thus, by forming a solidified body of the seal grout Ms having the same strength as the ground G between the sleeve tube 12 and the ground G, the hole wall of the boring hole A8 is stabilized and injected. The grout Mg of the material is prevented from leaking along the tube wall of the sleeve tube 12.
[0010]
The above-mentioned sleeve injection method is effective for vertical boring holes, but has a drawback that the ground cannot be improved in the horizontal direction by avoiding, for example, a structure on the ground. In particular, in areas such as dense urban centers of buildings, it is difficult to carry out the sleeve injection method described above on the ground directly under the buildings. In addition, this method cannot be applied when the apparatus cannot be approached even in an open space.
[0011]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above-mentioned problems of the prior art, and can surely improve the area where soft ground needs to be improved in the horizontal direction, and also improve the area below the structure. The purpose is to provide a possible soft ground solidification method.
[0012]
[Means for Solving the Problems]
According to the present invention, a machine (3) capable of boring freely is disposed on one of the ground surfaces of the ground (G) to be improved, and a feeder (10) for feeding the sleeve pipe (12) is disposed on the other ground surface, The boring drive (3a) of the machine (3) is operated to cause the flexible excavating rod (4) to enter from the incident point (Ei), and the pilot hole (7) into the underground area of the ground structure (1) In the solidification method using the sleeve tube that improves the ground by injecting cement milk from the sleeve tube (12), the pilot hole (7) is drilled and then expanded to the flexible drilling rod (4). A boring head (15) having a diameter bit (16) and a nozzle (17) for softening the ground and injecting cement milk (Ms) into the enlarged diameter hole (8) is coupled to the boring head (15). Non-rotating screw A sleeve tube (12) having an injection nozzle (13) is attached via a bell (19), and the flexible excavation rod (4) is pulled to the incident point (Ei) side to excavate the enlarged diameter hole (8). The cemented milk (Ms) is injected and filled into the expanded diameter hole (8), and then the injection material (Mg) is injected from the injection material injection pipe (20) inserted into the sleeve pipe (12). The injection material (Mg) is made to expand the rubber sleeve (14) covering the injection nozzle (13) of the sleeve tube (12) and to crush the solidified cement milk (HMs) to penetrate into the ground (G). ing.
[0013]
In carrying out the present invention, it is necessary to use a known boring machine capable of excavating the ground (G) in a curved shape. Further, the cement milk (Ms) to be injected and injected into the expanded diameter hole (8) having the expanded diameter of the pilot hole (7) needs to be selected so that the strength after solidification is the same as the strength of the ground (G). .
By the solidified cement milk (HMs) of the expanded diameter hole (8), the hole wall of the expanded diameter hole (8) is stabilized, and the sleeve tube (12) outer wall of the injection material (Mg) as illustrated in FIG. The leakage CMg along is prevented.
[0014]
The cracking of the solidified cement milk (HMs) may be performed in advance with pressurized water before the injection material (Mg) is injected, or the injection material (Mg) depending on the properties of the solidified cement milk (HMs). It may be cracked directly at the time of injection by the injection pressure of. ,
According to the construction method of the present invention, the ground can be improved by drilling the construction area (G) below the ground structure directly from the ground outside the structure.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the substantially same thing among the name and code | symbol used by the prior art is demonstrated by the same name and code | symbol.
[0016]
1 to 6 show an embodiment of the present invention.
It is the soft ground G of the improvement required that the area | region including the underground of the ground structure 1 becomes a construction area | region.
[0017]
In FIG. 1, excavation of the pilot hole 7 is started. First, the machine 3 capable of boring freely is arranged on one side of the ground G to be improved, and the arrangement of the feeder 10 for sending the sleeve tube to the other side of the ground is determined. At this stage, the positions of the entrance point Ei and the exit point Eo of the pilot hole 7 are already determined.
Next, the boring drive unit 3a of the machine 3 capable of boring is operated to cause the flexible excavating rod 4 for excavating the pilot hole to enter from the incident point Ei, and excavation of the ground G is started. Then, the pilot hole 7 is advanced by excavation with the inclined linear portion 7a, the bent portion 7b, and the horizontal portion 7c.
[0018]
In FIG. 2, the bent portion 7d and the obliquely rectilinear portion 7e are continuously excavated from the state of FIG. 1, and excavated to the emission point Eo to complete excavation of the pilot hole 7.
[0019]
In FIG. 3, the pilot hole 7 is expanded in diameter, and an operation for injecting cement milk as a sealing material is performed. That is, as shown in FIG. 6, the diameter-expanded boring head 15 is coupled to the flexible excavating rod 4. The boring head 15 is provided with a plurality of diameter-expanding bits 16 and a nozzle 17 for softening and heat-dissipating excavation heat and spraying cement milk Ms into the expanded diameter-expanded hole 8. Has the function of filling.
The end of the sleeve tube 12 wound around the feeder 10 via the non-rotating swivel 19 is attached to the boring head 15. Reference numerals 13 and 14 denote the injection nozzle shown in FIGS. 11 and 12 and a rubber sleeve that covers the injection nozzle.
[0020]
FIG. 4 shows a state where the flexible excavation rod 4 is pulled toward the incident point Ei and the enlarged diameter 8 is excavated by the boring head 15. By pulling up the flexible excavation rod 4, the expanded diameter hole 8 is excavated and the expanded diameter hole 8 is injected and filled with cement milk Ms (see FIGS. 11 and 12). FIG. 4 shows a state in which the diameter expansion and cement milk Ms are injected and filled up to the obliquely rectilinear portion 8a, the bent portion 8b and the horizontal portion 8c.
[0021]
FIG. 5 shows a state in which the diameter expansion by the diameter expansion bit 16 of the boring head 15 and the injection filling of the cement milk Ms have been completed from the horizontal portion 8c to the incident point Ei through the obliquely rectilinear portion 8d.
[0022]
Next, as shown in FIGS. 8 to 11, the injection material injection tube 20 is inserted into the sleeve tube 12, and the grout Mg of the injection material is injected from the injection port 23. Referring to FIGS. 11 and 12, the injected grout Mg pushes up the rubber sleeve 14 from the injection nozzle 13 and penetrates into the ground G through the solidified cement milk HMs previously cracked with pressurized water. The penetrated grout Mg is solidified to strengthen and improve the ground G. Depending on the properties of the solidified cement milk HMs, cracking may be performed at the time of pouring grout Mg without cracking with pressurized water.
[0023]
In this way, it is possible to improve the ground beneath the structure, which cannot be achieved by injection of injection material by vertical boring.
[0024]
In the above embodiment, the incident point Ei and the outgoing point Eo are linear when viewed from the upper surface of the ground, but may not be linear.
[0025]
In addition, each said embodiment shown to the last is an illustration to the last, and is not the description of the meaning which limits the technical scope of this invention. For example, the material for preventing the collapse of the expanded diameter hole 8 and preventing the leakage of the injected material may not be the cement milk Ms but may be a similar material, and the method of drawing the sleeve tube into the expanded diameter hole is another means. It may be.
[0026]
【The invention's effect】
The effects of the present invention are listed below.
(1) By the solidification method using the sleeve tube of the present invention, the ground can be improved by injecting an injection material by drilling a borehole and expanding the diameter of the soft ground below the existing structure to be avoided.
(2) There may be a distance between the ground boring start point and the required ground improvement area. Therefore, it is possible to arbitrarily select a suitable site that does not affect the ground structure and can take a construction space including the arrangement of machines capable of boring freely.
(3) Since the ground improvement in the horizontal direction, one boring hole can be lengthened and the number of boring machines can be reduced.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view showing an oblique hole portion, a bent portion, and a horizontal portion of a pilot hole in a flexible excavation rod according to an embodiment of the present invention.
FIG. 2 is a side sectional view showing a state in which a pilot hole has penetrated following FIG. 1;
FIG. 3 is a side cross-sectional view showing a state where a diameter-enlarged bit with a sleeve tube is attached to a flexible excavation rod following FIG. 2;
4 is a side cross-sectional view showing a state in which the diameter-expanded hole in which the cement milk is injected is advanced to the horizontal portion after the diameter-expanded excavation with the diameter-expanding bit following FIG. 3;
FIG. 5 is a side cross-sectional view showing a state in which the diameter-enlarged hole into which cement milk has been sprayed has reached the ground part following FIG. 4;
FIG. 6 is a side sectional view showing a relationship between a sleeve tube, a diameter expanding bit, and a flexible excavation rod.
FIG. 7 is a side view showing a state in which a sleeve pipe is inserted into a sealing material in an example of a sleeve injection method in conventional vertical excavation.
FIG. 8 is a side view showing a state in which the injection material injection pipe is inserted into the sleeve pipe following FIG. 7;
FIG. 9 is a side view showing a state in which the sealing material is cracked with the pressurized water from the injection material injection pipe following FIG. 8;
10 is a side view showing a state in which grout is injected and injected from the injection material injection tube into the ground after FIG. 9;
FIG. 11 is a side sectional view showing a structural relationship between a sleeve tube and a chemical solution injection tube in a conventional sleeve injection method.
FIG. 12 is a side sectional view for explaining the effect of solidified cement milk in a sleeve injection method.
[Explanation of symbols]
Ei ... Pilot hole entrance point Eo ... Pilot hole exit point G ... Soft ground Ms ... Cement milk Hms ... Solid cement milk Mg ... Injection material (grouting)
3 ... Rotary boring machine 4 ... Flexible excavation rod 5 ... Rod heads 7, 7a, 7b, 7c, 7d, 7e ... Pilot holes 8, 8a, 8b, 8c ... -Diameter expansion hole 12-Sleeve pipe 13-Injection nozzle 14-Rubber sleeve 15-Diameter expansion boring head 16-Diameter expansion bit 20-Injection material injection pipe

Claims (1)

  A machine (3) capable of boring freely is disposed on one of the ground surfaces of the ground (G) to be improved, and a feeder (10) for sending a sleeve pipe (12) is disposed on the other surface of the ground (G). Actuating the boring drive (3a) to cause the flexible excavating rod (4) to enter from the incident point (Ei) and excavating the pilot hole (7) in the underground area of the ground structure (1) In the solidification method using a sleeve pipe for improving the ground by injecting cement milk from the pipe (12), after drilling the pilot hole (7), the flexible drilling rod (4) is provided with a diameter expanding bit (16) and A boring head (15) having a nozzle (17) for softening the ground and injecting cement milk (Ms) into the enlarged diameter hole (8) is coupled, and a non-rotating swivel (19) is connected to the boring head (15). The Then, a sleeve tube (12) having an injection nozzle (13) is attached, and the flexible excavation rod (4) is pulled toward the incident point (Ei) side to excavate the diameter expansion hole (8), and the diameter expansion hole (8) Cement milk (Ms) is injected and filled, then injection material (Mg) is injected from the injection material injection pipe (20) inserted into the sleeve tube (12), and the injected injection material (Mg) is injected. A sleeve tube characterized in that the rubber sleeve (14) covering the injection nozzle (13) of the sleeve tube (12) is expanded to crush the solidified cement milk (HMs) and permeate the ground (G). Solidification method used.

Images