JPS6357562B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a progressive chemical injection method for improving the ground while performing packing through injection.

Recent developments in chemical injection methods and equipment have been remarkable. To explain the recent general-purpose method, first, the injection port formed in the outer tube is wrapped with a sleeve, and the inner tube with rubber packers on the top and bottom is moved up and down, and the gel time is from several minutes to several tens of minutes. There is a so-called soretanshi method in which a chemical solution is infiltrated into the tank, or a strainer injection method in which a strainer injection pipe is press-fitted and injected through a number of injection ports. This type of construction method is excellent in that it allows for natural ground improvement by allowing the chemical solution to penetrate through the soil with a long gel time. However, for sandy soils that are heterogeneous and saturated with groundwater, or complex clay soils, long gel time chemicals may escape into weak layers or be diluted by groundwater. The desired improvement effect cannot be expected, and since the injection pipe is buried, it is not economical and may actually impede subsequent civil engineering work.Furthermore, because the gel time is long, it takes a long time to cure, which increases the construction time. In addition, it is difficult to control the injection pressure, and in particular when injecting while splitting the so-called sleeve grout around the entire circumference of the injection pipe and the hole wall, the injection pressure cannot be used as a guideline for construction technology. This was one of the obstacles to reliable construction.

Next is the high-pressure injection method, which uses high pressure to jet chemical solutions while agitating the ground. Although this construction method is effective for homogeneous ground with a low N value, since a long gel time chemical solution is used, the chemical solution is often washed away, and is not suitable for the purpose of improving a predetermined limited area. In addition, it is not suitable for improving complex ground, requires sludge drainage and drainage chemical treatment, and requires high-pressure, high-discharge construction, which increases the cost of safety measures.

In place of these methods, the LAG method described in Japanese Patent Application Laid-Open No. 52-48217 has recently been widely used. This method is extremely superior in that it can reliably improve a limited area using a chemical solution with an extremely short gel time. However, due to the nature of the construction method, it is not possible to slowly penetrate and inject chemicals with a long gel time into sandy ground.

The present invention effectively utilizes the features of the above-mentioned construction methods. That is, in the present invention, a first injection part is formed on the peripheral wall of the distal end of the injection tube that performs drilling and injection in one piece, and the flow paths for each liquid of the two-component curable chemical are made independent up to the first injection part. A second injection part is formed on the tip side of the first injection part, and the injection pipe having the first injection part and the second injection part is installed at a predetermined depth in the target ground. The respective liquids are passed through the independent flow path of the injection pipe at the position and are combined near the first injection part, and a two-component hardening chemical solution is injected into the surrounding ground from the first injection part to solidify the area near the first injection part with the chemical solution. After that, without moving the injection pipe, or by moving it slightly, injection material of the same type or different type as the chemical solution is injected into the surrounding ground from the second injection part through the injection pipe. The method is characterized in that an improved body is created, and then the injection tube is further moved to create the aforementioned packed solidified body and to create an improved injection body.

The present invention will be explained below with reference to the drawings. Figure 1~
FIG. 6 shows an example of the tip device 1 of the injection device according to the present invention. This tip device 1 is connected to a swivel 3 via a connecting pipe 2, and the tip device 1 is connected to a swivel 3 via a connecting pipe 2.
The three flow paths are independently configured. Reference numeral 10 denotes an outer tube of the tip device 1, and a connecting tube 12 and a tip shoe 16 having a cutting blade 14 are threadedly connected to the tip side (right side in FIG. 1) of the outer tube 10, respectively. Further, a connecting tube 18 is connected to the proximal end side of the outer tube 10. Reference numeral 20 denotes a valve chamber provided inside the outer tube 10, and a spool valve 22 is installed inside the valve chamber 20. Reference numeral 24 denotes a flow path element installed in the connecting pipe 18 with a gap 26, and this flow path element 24 has a second A
The liquid path 28 and the second B liquid path 30 are formed independently. In addition, the flow path element 24 includes a second A liquid path 28.
A joint 34 constituting the first A liquid path 32 that communicates with
, and a joint 38 constituting a first B liquid path 36 that communicates with the second B liquid path 30 are screwed together. The space between the joints 34 and 38 and the connecting pipe 18 forms a first C channel 40. Further, both sides of the channel element 24 are chamfered, and this space and the gap 26 constitute a second C channel 42.

On the other hand, a first joint 44 is installed at the distal end of the outer tube 10, and a second joint 46 is installed at the distal end of the connecting pipe 12. In addition, the valve chamber 20 has outlet ports 48 and 5.
0 is formed symmetrically with respect to the center, and the half circumference of the valve chamber 20 forms a guide gap 52 with the outer tube 10, and this guide gap 52 communicates with the outlet ports 48, 50, and It communicates with the first injection port 54 . A guide hole 56 is formed on the distal end side of the outlet 48 .

The spool valve 22 is always urged toward the proximal end by a spring 58 whose seat is the end surface of the first joint 44 . The spool valve 22 has a third A liquid path 60.
A third B liquid path 62 is formed and communicates with the second A liquid path 28 and the second B liquid path 30, respectively. Further, on the proximal end side of the outlet ports 48 and 50 of the spool valve 22, outlet ports 64 and 66 are formed, and a guide hole 68 that coincides with the non-moving guide hole 56 of the spool valve 22 is also formed. On the other hand, the valve chamber 20
One side is chamfered to form a third C flow path 70 communicating with the second C flow path 42, and the other side is chamfered to form a third C flow path 70 communicating with the second C flow path 42.
6 to the tip of the valve chamber 20
is formed.

Further, the inside of the tip of the valve chamber 20 forms a fourth C flow path 74, which communicates with the third C flow path 70. Further, in the first joint 44, a fifth A channel 76 is formed that extends from the circumference to the center and exits to the bottom, and a fifth C channel 78 that passes from the center to the side and exits downward is formed. And the first joint 44 and the second joint 4
6 is connected by a connecting pipe 80.
The gap between the connecting pipe 80 and the connecting pipe 12 is a sixth C channel 82, and although not shown, the second joint 4
6 and the tip shoe 16, and communicates with the seventh C flow path 84. In the middle of the seventh C channel 84,
It is normally closed by a rubber annular check valve 86 having a tongue portion 86a. Furthermore, the second joint 4
6 is formed with a sixth A flow path 88, which is blocked by a check valve 90 in the middle thereof. A guide 92 is screwed onto the tip of the second joint 46, and the inside thereof forms a seventh A flow path 94. 9
A spring 6 urges the check valve 90 to seal the sixth A flow path 88 using the guide 92 as a seat. Further, a discharge hole 98 is formed in the lower circumferential wall of the guide 92, and the liquid discharged from the discharge hole 98 and the liquid passing through the seventh C channel 84 are configured to intersect at right angles. 100 is a second injection port.

In the injection device configured in this way, when liquid A is now pumped, liquid A will flow through each of the liquid A channels 32, 28,
60 in order, through the guide holes 68 and 56, and then
It passes through the liquid paths 72 and 76, passes through the inside of the connecting pipe 80, reaches the sixth A flow path 88, exits to the seventh A flow path 94 while pressing down the check valve 90, and is discharged from the discharge hole 98 to the second A flow path. It is discharged forward from the injection port 100.

Also, when C liquid is pumped, each of the C flow paths 40, 4
2, 70, 74, 78, and 84 in order, and while bending the tongue 86a of the annular check valve 86, the tongue 86 of the annular check valve 86 is bent.
a and the guide 92, and the second injection port 100
It is discharged from. In this case, if the A liquid is discharged from the discharge port 98 at the same time, the A liquid and the C liquid will join orthogonally for the first time here, and the combined liquid will be injected from the second injection port 100.

Further, when liquid B is pumped, each of the B flow paths 36,
Pass through 30 and 62. At this time, when liquid A is also pumped as described above, the pressure of transporting both liquids A and B overcomes the biasing force of the spring 58, and the spool valve 2
is pushed down for the first time. As a result, the outlet 64,
66 coincide with the outlets 48 and 50, respectively, liquid A enters the guide gap 52 from the outlet 48, and liquid B enters the guide gap 52 from the outlet 50. These liquids A and B contact and mix countercurrently at the inlet of the first injection port 54 to become a uniform liquid, which is injected from the first injection port 54 into the surrounding ground. Note that as a result of the spool valve 22 being pushed down, the guide holes 68 and 56 become misaligned, and the flow of liquid A toward the tip side is blocked.

In this way, according to the injection device, liquid A alone can be discharged from the second injection port 100, liquid C alone can be discharged from the second injection port 100 through the discharge port 98, and both liquids AC can be discharged from the second injection port 100. 98 outlet and discharged from the second inlet 100, and the AB liquids are passed through the outlet ports 48 and 50 and countercurrently merged in the guide gap 52, and then discharged from the first inlet 54. In addition, if the individual feeding pressure is made larger than the biasing force of the spring 58, various discharge methods can be selected, such as discharging only liquid A or only liquid B from the first injection port 54 through the outlet 48 or 50. .

Next, the construction method of the present invention using this injection device will be explained with reference to Figs. 7 to 11. First, as shown in Fig. 7, the injection pipe is gradually press-fitted while rotating, and as shown in Fig. 8. Drill the hole to the position. During this drilling, water is pumped as liquid A, and air is pumped as liquid C, and these are used as drilling lubricants. Of course, water may be pumped only through appropriate channels. Next, both liquids A and B, which are two-component curable injection liquids, preferably those having a gel time of 30 seconds or less, more preferably 15 seconds or less, are pumped and are combined in a countercurrent manner as described above for the first injection. It is injected into the surrounding ground from the entrance 54 to create a pack solid P. In this case, a shorter gel time is advantageous in that the injected chemical solution does not run away and the solidified body P can be formed only in a predetermined area.

Once the formation of this solidified body P is completed, as shown in Fig. 9, the injection material is pumped through the A flow path and the C flow path, and the AC liquids are brought together orthogonally as described above. It is discharged from the second injection port 100. In this case, it is preferable not to move the injection tube beyond the stage shown in FIG. 8 in order to prevent the edge of the pack solid P and injection tube from breaking and the injection material flowing out to the base side. Depending on the target ground, the injection pipe may be moved slightly in the axial direction. Also, the second injection port 1
The injection material to be discharged from 00 should preferably have a gel time of 60 seconds or more, which is suitable for osmotic injection, and should be injected slowly at low pressure. However, depending on the ground, an instant-setting two-component curing injection material with a short gel time may be used as described above. When injecting the injection material, the pack solidified body P is created at the rear, so the injection material does not flow out to the proximal side, and the injection material is injected only to the front and the periphery, creating an improved injection body G. Ru.

After that, holes are drilled again in the same manner as in the process shown in Fig. 7, and the process is moved to the next step (Fig. 10), a pack construction body P' is created (Fig. 11), and an injection improvement body is created (as shown below). (process not shown).

In such a construction method, the first injection port 54 is formed on the peripheral wall of the injection pipe, and the second injection port 100 is formed on the distal side of the first injection port, so that the first injection port 54 is injected into the package. A solid body P can be formed from the second injection port 100, and an improved injection body G can be formed from the second injection port 100. Conventionally, in the forward injection method, an injection tube with only one injection port formed at the tip has been used. Therefore, it is necessary to use a construction method that involves constructing an improved structure that improves the ground and has a packing effect through injection, and then moves the injection pipe through a hole to create the next improved structure. When creating the next improved body, since the previous improved body and the injection tube are separated by the rotation of the tube as seen in the drilling and the water supply, the injection material flows from the gap to the proximal side. It leaked out and it was impossible to reliably create the next improved body. However, in the method of the present invention, injection is made from another second injection port 100 to the tip side at approximately the position where the pack solidified body P is created, so that the outflow of the injection material can be prevented and a reliable injection improvement body can be obtained. It has the effect of creating G.

Furthermore, the construction method of the present invention uses a forward construction method. Therefore, since the next injection is performed while constantly improving the base side, the above-mentioned separate injection ports prevent the chemical solution once injected into the surrounding ground from flowing out to the base side. This method allows reliable ground improvement at all times, and since it always creates a self-supporting hole wall before proceeding to the next construction step, so-called hole bending can be prevented, and the ground improvement can be carried out to the desired extent. Construction up to shaku is also possible.

In the above example, the chemical solution for creating pack solids and the injection material for creating an improved injection body may be of the same type, but at least the chemical solution for creating pack solids must have a short gel time. is desirable in order to create a reliable pack consolidation at that location. And as an injection material for creating an improved injection body,
As mentioned above, if an instant-setting chemical solution containing water glass as the main ingredient is used, clayey soil can be improved by splitting injection, or if a water glass to cement-based long gel time chemical solution is used for slow penetration injection. It is effective for sandy soil. Therefore, improvements can be achieved by appropriately selecting the injection material for complex ground. On the other hand, when chemical liquids are brought into contact and mixed in a countercurrent and/or orthogonal manner as in the above example,
For example, the gel time in a beaker test was 15 seconds, but when using the same material and the above device, the gel time was 4 to 4 seconds.
It has the advantage of instantaneous curing with a gel time of 5 seconds.

Furthermore, in the above example, when forming the pack solidified body P, it is extremely preferable to discharge air from the second injection port 100. That is,
When a chemical solution is simply injected from the first injection port 54, the discharged chemical solution passes between the hole wall and the second injection port 100.
However, if the air is ejected, it will be blocked by the air and the second injection port 100 will be prevented from clogging. If it stops happening,
It serves as a guideline to indicate that the pack solidity has been completely formed, and has the effect of being able to check its formation. In making this possible, the injection device has a major role.

By the way, FIG. 12 shows an example in which the configuration of the first injection part for forming pack solids is different, and the above device mixes inside the pipe, but the positions of the outlets 48, 50 and the outlets 64, 66 are different. A different injection port 54' is formed in a pair with the injection port 54 in the axial direction, and both liquids A and B are combined outside the tube to form a solidified pack. FIG. 13 shows another example of the second injection part, which has a tubular guide 9.
2' is provided so that both liquids A and C are spouted forward. As described above, the structures of the first injection part and the second injection part of the present invention are not limited in any way.

In addition, in the injection device in the above example, the two-component curable material is merged at the base of the C liquid supply path, for example, at the swivel portion or a Y-shaped tube portion provided near the swivel, and the two-component curable material is passed through the C liquid feed path. By discharging from the second injection port 100, injection from the first injection part and injection from the second injection part can be achieved simultaneously. This simultaneous injection has the advantage of halving the construction effort.

As described above, the present invention has particularly significant practical effects.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an example of a device according to the present invention, and FIGS. 2 to 6 are respectively -
, -, -, - and - arrow sectional views, Figs. 7 to 11 are sectional views showing the construction method of the present invention in the order of construction, and Fig. 12 shows a structure with a different aspect of the first injection part. 13, a is a longitudinal cross-sectional view, b, c, and d are cross-sectional views along X-X, Y-Y, and Z-Z, and FIG. 13 is a cross-sectional view of a structure with a different aspect of the second injection part. DESCRIPTION OF SYMBOLS 1... Tip device, 2... Connecting pipe, 3... Swivel, 10... Outer pipe, 16... Tip shoe, 20... Valve chamber, 22... Spool valve.

Claims (1)

[Claims] 1. A first injection part is formed on the peripheral wall of the distal end of the injection tube that performs drilling and injection with one, and two
A flow path for each of the liquid-curing chemical liquids is formed independently in the injection pipe, a second injection part is formed on the tip side of the first injection part, and the first injection part and the second injection part are formed at a predetermined depth in the target ground. An injection pipe with two injection parts is installed, and at this position, the respective liquids are passed through the independent flow path of the injection pipe and merged near the first injection part, and from the first injection part to the two injection parts.
A liquid hardening chemical is injected into the surrounding ground, and the vicinity of the first injection part is solidified with the chemical to form a solidified pack.Then, the injection pipe is passed through the injection pipe at that position without moving, or after being moved slightly. Injecting the same type of injection material or a different type of injection material as the chemical solution into the surrounding ground from the second injection part to create an injection improvement body, and then moving the injection pipe further to create the above-mentioned pack solidified body and injection improvement body. A chemical injection method characterized by: 2. The chemical liquid injection method according to claim 1, wherein the hardening chemical liquid for forming the pack solidified body is a two-component hardening liquid and has a gel time of 30 seconds or less. 3. The liquid chemical injection method according to claim 1, wherein the injection material for creating an improved injection body is a permeable injection material having a gel time of 60 seconds or more.