JP2878892B2 - Grout three-phase injection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase injection method using a grout for strengthening in addition to a quick-setting grout and a loose-setting grout (penetrating grout).

[0002]

2. Description of the Related Art In addition to injection of permeable grout having a long setting time, in the 1975s, injection of so-called instantaneous grout having a setting time of 60 seconds or less has been carried out. Effectiveness has also been confirmed. In this case, the quick-setting grout is usually obtained by mixing and mixing a reactant with water glass, and by injecting the same, a gap around the injection pipe is packed to grind the grout to the ground. The purpose is to prevent runoff and to inject mainly into coarse gaps in the ground to fill the gaps. The injection mode at this time is usually in a pulse form.

On the other hand, at the same time, by using a solution-type flash grout and a solution-type osmotic grout together,
A so-called composite injection method has been proposed, in which pulsating grout is injected in a pulsating manner, and osmotic grout is injected into fine gaps that cannot be injected with this flash grout.

[0004]

SUMMARY OF THE INVENTION
Although this is an ideal mode of ground improvement, it is not always effective especially for highly permeable ground including a gravel layer.
In other words, even if a water-glass solution-type quick-setting grout is injected into a highly permeable ground including a gravel layer,
The gap between the gravel layers cannot be sufficiently clogged, and the improvement in strength is low. Further, there is a problem that the improvement zone is small.

[0005] Further, even if permeable grout is injected in this state, the permeable grout often escapes because the rough gap in the ground has not yet been sufficiently filled, so that efficient improvement cannot be expected. .

[0006] Therefore, a main object of the present invention is to improve the effect of improvement even on a ground with high water permeability including a gravel layer, in particular, to increase the strength after the improvement and to increase the improved diameter.

[0007]

The above object is achieved by injecting a solution-type or suspension-type instantaneous grout having a setting time of 60 seconds or less through an injection pipe inserted into the ground. From the injection position or the tip side thereof, a suspension-type reinforcing grout having a longer setting time and a higher homogel strength than the flash-setting grout is injected, and then, from the injection position of the reinforcing grout or the tip side thereof, The solution can be solved by injecting a solution type osmotic grout which has a longer setting time than a flash grout.

[0008]

According to the present invention, when grout is injected in three phases (in terms of using three types of grout), as shown in the examples described later, the grout is improved particularly for a ground having high water permeability including a gravel layer. It has the effect that the strength afterwards is high and the improved diameter becomes large.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. 1 to 5 are representative conceptual diagrams of the method of the present invention,
First, as shown in FIG. 1, while drilling the ground with an injection pipe 1 also serving as a drilling rod, or by inserting an injection pipe into a hole drilled by a boring rod or a casing rod (not shown), The injection tube 1 is inserted at a predetermined depth.

Next, as shown in FIG. 2, an instantaneous grout S is injected into the ground from a distal end portion of the injection pipe 1, for example, an injection port 2A formed slightly closer to the base side than the distal end of the injection pipe 1.
As the flash setting grout, a solution type typified by a water glass type having a setting time of 60 seconds or less or a cement type or cement bentonite type suspension type is used. The injection of the instantaneous setting grout fills the gap with the drilled wall around the injection pipe 1 and performs pulsating injection into the rough gap in the ground to prevent the subsequent grout from flowing to the ground side. To achieve a packing effect to improve the strength and improve the strength by roughening a large gap.

Thereafter, as shown in FIG.
A or a suspension-type reinforcing grout R having a longer setting time and a higher homogel strength than the flash-setting grout S is injected from the inlet A or from the injection port 2B from the tip side. As the suspension type grout, a cement type or cement bentonite type is used. By the injection of the reinforcing grout R, a large gap in the ground is roughened, and the strength is increased.

At this time, by the use of the instantaneous setting grout S,
Above the injection port 2B, the gap between the injection pipe 1 and the drilling wall is filled, and pulsating injection is performed to form a packer. Therefore, the reinforcing grout R does not escape to the ground side. It is mainly injected below the improvement zone by Madokayui grout S. In addition, a part of the fluid has a function of strengthening the ground by penetrating into the vein-like injection part of the instantaneous setting grout S and pushing it into the ground gap or into the insufficiently injected part. Since the reinforcing grout R is a suspension type, there is also an advantage that the material cost can be reduced.

Moreover, since a suspension type grout R is used as the reinforcing grout R, the effect of improving the strength is greater than when a solution type quick setting grout is simply injected. In addition, the present invention does not exclude the use of a suspension type grout as a quick setting grout.
Since it is an instantaneous setting grout, it mainly stays only near the injection pipe 1 and is solidified, so that it does not penetrate to a certain distance.

However, according to the present invention, as the reinforcing grout R, one having a setting time longer than at least the instantaneous setting grout is used.
Penetrates farther and has the advantage that the improved diameter becomes larger.

Subsequently, as shown in FIG. 4, an injection hole 2C at the injection position of the reinforcing grout R or at a tip side thereof.
Then, a solution-type permeable grout L is poured from the instantaneous setting grout having a longer setting time than that of the instantaneous setting grout. As the solution type grout, a water glass type can be typically used. This permeable grout L is infiltrated and injected into fine gaps in the ground due to the fact that the material is of a solution type and the consolidation time is long. Further, it penetrates into the roughening strengthening zone formed by the previously formed reinforcing grout R, or passes through or breaks through the strengthening zone and reaches farther to be consolidated.

In this way, the unique functions of the instantaneous grout S, the strengthening grout R, and the permeable grout L are related to each other, and as a whole, a very ideal ground reinforcement can be achieved.

Thereafter, the injection tube 1 is advanced or preferably stepped up by a predetermined length as shown in FIG. 5, and at that stage, the steps shown in FIGS. Enhance overall.

The injection ratio of the instantaneous grout S, the reinforcing grout R, and the permeable grout L is, for example, when Q = (S + R + L), S = Q ×
(5-20%), S = Q × (15-30%). The setting time of the instantaneous setting grout S is preferably 20 seconds or less. The consolidation time of the reinforcing grout R is preferably 30 seconds to 5 minutes. The consolidation time of the permeable grout L is desirably 3 minutes or more.

The injection ports of the instantaneous grout S, the reinforcing grout R and the permeable grout L can be at the same injection position when at least two types of grout are injected, but are preferably from the base side. to the tip side, Shun binding grout S, it is preferable inlet reinforcing grout R and permeability grout L are formed in this order.

When the grout S, the reinforcing grout R and the permeable grout L are injected, the main material and the reaction material are mixed and mixed before entering the injection pipe 1 or by using a Y-shaped pipe provided at the mouth thereof. In addition to the aspect of the mixing, preferably, in order to prevent the flow path from being clogged due to the consolidation in the flow path in the injection pipe 1, the flow is mixed and mixed in the injection pipe 1, particularly, in the pipe at the distal end thereof.

As the structure of the tip device for the in-pipe confluence mixing, there are known so-called LAG method, DDS method,
The tip device for the instantaneous injection method such as the MT method can be diverted, and the tip device for the compound injection method such as the bi-mode method can also be used.

However, as described above, the position of the injection port differs in the depth direction, and the one in which the flow paths are basically different in order to prevent adhesion and solidification of the material in the flow path in the pipe. Is preferred. In particular, when the instantaneous grout S is injected, it is preferable that the flow path of the main material and the flow path of the reaction material be independent up to the merging and mixing section.

FIGS. 6 to 10 show a first example of this injection tube.
A second example is shown in FIGS. First, the structure and injection mode of the first example will be described.
1, a guide body 12 is provided inside, and four flow paths 13, 14,
15 and 16 are formed. The first flow path 13 penetrates the center of the guide body 12, and the other second flow path 14, third flow path 15, and fourth flow path 16 are formed by the concave portion of the guide body 12 and the outer pipe 1.
1 is formed. The above-described inlets 2A, 2B, and 2C are formed in the outer wall portion at the distal end of the outer tube 11, and the distal end serves as a discharge port 2D for drilling water W.
Further, a drill bit 17 is integrated with the tip of the outer tube 1 so that the injection tube 10 is used as a drill rod.

Further, a step portion 1 is provided below the first flow path 13.
2a, a spool valve chamber having an enlarged outer diameter is formed,
A first spool valve 19 having a small diameter portion 19a in the middle is provided in the spool valve chamber . This first spool valve 1
A first communication hole 12b is formed in the guide body 12 at a position corresponding to the lower part of 9, and communicates the second flow path 14 with the spool valve chamber . Further, a counterflow merging chamber 12c is formed which communicates with a position corresponding to the upper body and the lower body of the first spool valve 19 and communicates with the inlet 2A.

Below the first spool valve 19 in the spool valve chamber 18, a second spool valve 20, a third spool valve 21, and a fourth spool valve 22 are sequentially provided.

The cylindrical second spool valve 20 has a second communication hole 20a formed in a side wall thereof, and is in communication with the third flow path 15 when not in operation. The third spool valve 21 has an inverted bottomed cylindrical shape, and has a third communication hole 21a formed in a side wall thereof. The outlet hole 12d communicating with the inlet 2B is closed. Fourth spool valve 22
Is in the shape of a circular tube, and its upper part closes the pouring hole 12e communicating with the inlet 2C. Further, a check valve 23 is integrally formed so as to protrude upward into the lower end of the outer pipe 1 and close the lower end opening when the fourth spool valve 22 is lowered.

The drilling water W is supplied into the fourth flow passage 16 from the port having the 4-port swivel at the time of drilling and insertion shown in FIG. While drilling (see FIG. 6), the injection pipe 10 is drilled while being rotated in the circumferential direction by a known injection pipe installation machine. At this time, the drilling water W flows from the fourth flow path 16 to the third communication hole 21a.
From the third spool valve 21 through the fourth spool valve 22, and is discharged from the discharge port 2D to assist drilling.

Next, as shown in FIG. 2, when the instantaneous setting grout S is injected, as shown in FIG.
3, the main material A of the instantaneous grout S is supplied to the second flow path 14 and the reactant B is supplied to the first flow path 13 via the above-mentioned swivel. At this time, the first spool valve 19 is lowered by the supply pressure of the reactant B, and the small-diameter portion 19a coincides with the first communication hole 12b. At this time, the second spool valve 20, the third spool valve 21, and the fourth spool valve 22 are also lowered. With the lowering of the first spool valve 19, the reactant B flows into the counter-current merging chamber 12c and the main agent A
Through the communicating hole 12b, it passes through the periphery of the small diameter portion 19a and similarly flows into the counterflow merging chamber 12c. Due to these inflows, the main material A and the reaction material B are discharged from the first inlet 2A while being counter-currently mixed and mixed in the mixing and mixing chamber 12c.

Thereafter, as shown in FIG.
When the reinforcing grout R is supplied to the hopper, the first spool valve 19 is raised by the supply pressure, and the third spool valve 21 is lowered. As a result, the pouring hole 12d is opened, and the reinforcing grout R is supplied to the grout R. From the outlet 12d to the inlet 2
B is injected into the surrounding ground.

Subsequently, when injecting the permeable grout L, the permeable grout L is supplied to the fourth flow path 16 as shown in FIG. By this supply pressure, the third spool valve 2
1 rises, the outlet 12e is opened, and the permeable grout L is injected from the outlet 12e into the surrounding ground through the inlet 2C.

On the other hand, as shown in FIGS. 7 to 9, when each grout is injected, the fourth spool valve 22 is relatively fitted with the check valve 23, so that the grout is injected into the injection pipe 10. Inflow is prevented.

FIGS. 11 to 13 show an example of a tip device of the second injection pipe 30. Three first pipes 32 parallel to each other in the outer pipe 31 are shown.
A second conduit 33 and a third conduit 34 extend from the base side for injection.
It is connected to the first guide 35 of the tube 30. First conduit 3
2, the inside of each of the second conduit 33 and the third conduit 34 and the gap between these and the outer tube 31 are flow paths, and a total of four flow paths are formed. Below the first guide 35, a second guide 36 is provided at an interval, and a fourth conduit 37 is connected between the two. A third guide body 38 is provided below the second guide body 36 at intervals.

The first conduit 32 communicates with a first flow path 35A formed in the first guide 35, and the first flow path 35A
Is finally connected to the ring-shaped outlet 35a. The second conduit 33 is connected to a second flow path 35 formed in the first guide body 35.
B, and the second flow path 35B is finally connected to a ring-shaped outlet 35b. On the other hand, the outer tube 31 is interrupted and connected by the first guide body 35 at the portions where the outlets 35a and 35b are formed, and the lower end of the upper outer tube 31 and the upper end of the lower outer tube 31 are connected to the first guide. Skirt check valves 41 and 42 formed of a flexible material such as rubber are provided between the outer periphery of the body 35 and the base, and the skirt check valves 41 and 42 cover the outlet 35a and the outlet 35b, respectively. ing. Further, as shown in the figure, the inner surfaces of the lower end of the upper outer tube 31 and the upper end of the lower outer tube 31 are beveled at an angle.
a, 31a, as shown in FIG.
2 are allowed.

Thus, for example, the main material A of the instantaneous setting grout S is supplied into the first conduit 32, and the reactant B is supplied to the second conduit 3
3, when each of them flows out of the outlet 35a and the outlet 35b, the supply pressure of FIG.
The check valves 41 and 42 are bent as shown in FIG. at the same time,
In the small space surrounded by the check valves 41 and 42, the main material A
And the reactant B are mixed and mixed, and as a quick-setting grout S,
It is injected into the surrounding ground from the annular injection port 2A between the outer pipes 31, 31.

In the third conduit 34, for example, the above-mentioned reinforcing grout R is supplied. The reinforcing grout R passes through the third flow path 35C of the first guide 35 into the fourth conduit 37, and flows out of the fifth flow path 36A and the outlet 36a formed in the second guide 36.

At this time, similarly to the above-described structure example, the skirt-shaped check valve 43 is injected from the second injection port 2B while bending.

The permeable grout L is supplied to the first conduit 32 and the second conduit 32,
The pipe 33 is supplied to the gap between the third pipe 34 and the outer pipe 31 and passes through the seventh flow path 36B of the second guide 36 while passing through the sixth flow path 35D formed in the first guide 35. The flow reaches the eighth flow path 38A of the three guide body 38 and flows out from the outlet 38a. At this time, similarly to the above-mentioned structure example, the skirt-shaped check valve 44 is injected into the ground from the third injection port 2C while flexing.

When the injection pipe 30 is also used as a drilling rod, the outer pipe 31 connecting the second guide 36 and the third guide 38 is connected to the drill bit 40 as shown in FIG. The outer tube 31 'at the lower end can be replaced.
In this case, the drilling water W or the permeable grout L is
Pour out from the opening 31'a at the lower end of 1 '.

The solution type grout according to the present invention includes water glass-reactive material (curing material) type, urethane type, acrylic type, urea type and the like, and the suspension type grout includes cement bentonite and the like. Water-glass-cement, water-glass-cement-clay, water-glass-clay-
That contain such reaction material system. Water glass reactants include various alkalis such as calcium chloride, sodium carbonate, sulfate band, sodium aluminate, slaked lime, copper sulfate, sulfuric acid, sodium bicarbonate, sodium silicofluoride, glyoxal, etc., acids, alcohols, metal salts, etc. Can be appropriately selected. The setting time of the consolidation can be adjusted by the amount of the reactant, the pH, and the selection of the material.

[0040]

As described above, according to the present invention, the effect of improvement is high even on a ground with high water permeability including a gravel layer or a complicated alternate layer, and in particular, the strength after the improvement is high, and the improved diameter is obtained. Can be increased.

[Brief description of the drawings]

FIG. 1 is a first process chart for conceptually explaining a typical example of the present invention.

FIG. 2 is a second process diagram.

FIG. 3 is a third process diagram.

FIG. 4 is a fourth process diagram.

FIG. 5 is a fifth process chart.

FIG. 6 is a longitudinal sectional view of a first example of an injection pipe tip device used in a first stage operating state.

FIG. 7 is a longitudinal sectional view of a second stage operation state.

FIG. 8 is a longitudinal sectional view of a third stage operation state.

FIG. 9 is a longitudinal sectional view of a fourth stage operation state.

FIG. 10 is a view taken along line 10-10.

FIG. 11 is a longitudinal sectional view of a second example of the tip device of the injection tube to be used.

FIG. 12 is a longitudinal sectional view showing a main part of an injection state of a flash grout.

FIG. 13 is a view taken in the direction of arrows 13-13.

FIG. 14 is a longitudinal sectional view of a main part of an alternative example of the distal end outer tube.

[Explanation of symbols]

1. Injection tube, 2A, 2B, 2C ... Injection port, 10, 30 ...
Injection tube, S: grouting grout, R: grout for reinforcement, L
... penetrating grout.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Naoki Yamamoto, Inventor 2-2-11 Minamisuna, Koto-ku, Tokyo (72) Inventor Yasuo Miyazaki 2-16-6, Oimazato Minami, Higashi-Nari-ku, Osaka-shi, Osaka (72) Invention Person Yasunori Sato 8-11 Nadainmachi, Tennoji-ku, Osaka-shi, Osaka (56) References JP-A-4-14514 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 3/12 101

Claims (1)

(57) [Claims] 1. A solution-type or suspension-type quick-setting grout having a setting time of 60 seconds or less is injected from the tip through an injection pipe inserted into the ground, and then injected from the injection position or from the tip side. A suspension-type reinforcing grout having a setting time longer than that of the instantaneous grout and a high homogel strength is injected, and then the setting time of the instantaneous grout from the injection position of the reinforcing grout or from the tip side thereof. Characterized in that a long solution type permeable grout is injected.