JP2668376B2 - Grout injection method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grouting method for strengthening or stopping water in soft or stagnant ground.

"Prior Art and Problems to be Solved by the Invention" In recent years, research and development of ground improvement technology have been actively pursued with the development of construction work, but environmental conservation has also become an important issue.

In particular, in the grout injection method, from the viewpoint of water quality conservation of the groundwater, it is desired that the grout firmly solidifies the target area without deviating to the outside of the area, and consideration for the environment around the injection point, especially the ground surface. It is an issue that must be solved at the same time to prevent the rise of buildings and the deformation of buildings and buried objects.

By the way, the conventional grout injection method can be roughly classified according to the construction method. A retreating (upward) injection method in which step injection is performed sequentially from below to above while pulling up an injection pipe,
It can be divided into a forward (down) type injection method in which step injection is sequentially performed from the upper side to the lower side while lowering the injection pipe.

The former (receding type) is a rod injection method in which a boring rod that has been drilled in the ground and press-fitted is used as it is as an injection pipe, and stepwise injection is performed while pulling it up, and the device is simple and economically inexpensive. Therefore, most of them are currently using this method.

The structure of the boring rod used as the injection pipe is a single pipe with multiple pipes in addition to the single pipe.In particular, in the method using multiple pipes, the grout main agent and the reactant are separately introduced to the rod bottom through the flow path and mixed, so that instantaneous Sex grout can be injected,
It is generally used as a double pipe instantaneous construction method. Furthermore, using this double flow path, first, an instantaneous setting grout is injected, and then a loose setting is applied to the area where the instantaneous setting grout is injected. A grouting method has been developed in which a grout is injected, and a double-pipe composite grout method is also employed in which the double-pipe is sequentially pulled up and the flashing and loosening grout is alternately injected in the same step.

However, although there are improvements in these retractive multi-pipe construction methods that reduce the escape of grout to the distance, which is a drawback of the single pipe rod construction method, the injection grout, which is a drawback of the retractive injection method, deviates to the upper part of the ground. The tendency to be easy cannot be suppressed, which means that water and solidification are poor due to leaving unimproved parts between the upper and lower injection steps, water pollution due to deviation, and uplift or construction of the ground surface due to upper deviation. There is a risk of inducing deformation of objects and buried objects.

On the other hand, the latter (advanced type) is represented by the strainer method and the double packer method, in which the strainer pipe is inserted and installed after drilling the ground, and the steps are sequentially moved from the upper part to the lower part of the strainer part. According to these forward-type injection methods, the tendency of the grout to easily deviate to the upper part, which is a drawback of the former retractable rod injection method, can be suppressed. However, there is a disadvantage that the cost is generally high, for example, the injection pipe remains buried in the ground.

Furthermore, as a well-known method other than the strainer method and the double-packer method, a guide tube is installed up to the upper surface of the improvement area, and a cleaning tube is inserted into the guide tube to perform forward injection, and a high pressure is applied from the tip. After injecting water, drill the first ground for the first step, then pull out this washing pipe, connect the grout hose to the guide pipe and pressure feed the grout, and permeate the grout into the surrounding ground from the inside of the drilled hole. Then, the washing pipe is inserted again into the guide pipe and pressed into the solidified material of the first step, and after being pierced, it is pressed into the ground further below by the second step for the second step. There is also known a forward pouring method in which water is pumped to discharge slime in the pipe and around the cleaning pipe, pull out the cleaning pipe, inject grout into the surrounding ground in the same manner as described above, and repeat the same process ( Publication No. 57-39336).

However, in this method, the injection pipe is not left in the ground, but since the washing pipe is pressed into the solidified material formed in the previous step and the ground below it, there is a limit to the depth of the press-fitting work. There is a drawback that construction is impossible depending on the ground properties such as the gravel layer and the rock layer.

In any case, these methods have a problem in terms of work efficiency because the injection is stopped each time the step moves.

"Means for Solving the Problems" In order to solve the above-mentioned conventional problems, the present invention digs a boring rod to a predetermined depth in the ground, and then raises the boring rod to an arbitrary position, while drilling the drilling mark. Inject grout into the grout, press the injection tube inserted into the hollow part of the boring rod into the solidified body of the grout, and discharge the grout while sequentially pressing and dropping it, so that the rod construction method is simple and forward type. It is possible to continuously perform injection work by taking advantage of injection, and to certainly improve the target area, and to achieve water quality conservation, uplift of the ground surface, and prevention of deformation of buildings and buried objects. It proposes a typical construction method.

"Example" Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings. FIG. 1 shows the first embodiment of the present invention in the order of construction, and firstly, drilling water is pumped into the ground with the boring rod 1 at the tip. While excavating with the tip bit 2 to a predetermined improved depth (a), the injection pipe 3 is inserted into the boring rod 1 to the tip end (b), and the injection pipe 3 is left as it is to raise the boring rod 1 to a predetermined height. Pull up and inject tube 3
Grout S ₁ in the hole 4 left by pulling from the tip of the
(C), while continuing to pull up the boring rod 1 to the upper limit position of the improvement range, the injection pipe 3 is pulled up in the meantime, and grout S ₁ is injected and filled in the drilling mark 4 (d, e). The first step by the backward injection is completed.

Then, the injection tube 3 was pulled to the tip of the boring rod 1 is press-fitted from above into the consolidation of grout S ₁ filled in the first step, to discharge the grout S ₂ while sequentially pressed forward (f ), grout S ₂ was injected into the surrounding ground around the consolidated body of grout S ₁ while pressed forward sequentially Similarly, it ends the second step by advancing infusion.

In this case, the grout S ₂ is mainly injected through a crack when the injection pipe 3 is pressed into the consolidated body of the grout S ₁ , and the compact is broken by the ejection of the grout S _2. Is injected.

The boring rod 1 to be used may be a single tube or a multiple tube as long as the injection tube 3 can be inserted into the inside thereof. Seal around tube 3.

First grout S ₁ used in the process may be any of solution type and suspension type, and desirably may be the better but slow-setting property is Madokayui, yet these combinations May be

The point is that it can prevent the collapse of the drilling marks 4.
In particular, at the time when the injection pipe 3 is press-fitted in the second step, the consolidation strength (strength at the time of press-fitting, not meaning the subsequent day strength or final strength) is maintained so that it can be press-fitted relatively easily. It is necessary that the injection amount is such that at least the hole wall of the drilling trace 4 is maintained.

The grout S ₂ used in the second step is desirably in the form of a solution with good permeability and a slow setting, but may be a flash-setting or suspension type. it is necessary as it is capable of injecting the unconsolidated surrounding ground of the consolidated body around the S _1, Some when injecting only or only Yuruyui grout Madokayui grout initially Madokayui Injecting a soluble grout and then a slow-moving grout, when using either a solution type or a suspension type,
Alternatively, both may be used together.

The injection pipe 3 may be a single pipe or multiple pipes. In addition to a rigid pipe such as a steel pipe or a flexible pipe such as a synthetic resin pipe, the grout injected into the drilling marks 4 may be used.
As long as it retains the strength capable of press-fitted into the consolidated body in S _1, continuously pressed or every predetermined step without rotating with or rotating it.

At the tip of the injection pipe 3, for example, a rigid sharp cone 6
, And an arbitrary number of injection holes 7 are provided therein. In this case, the injection hole 7 may be provided so as to face downward so that the injection pipe 3 is press-fitted while the grout S ₂ is jetted.

When the injection pipe 3 is made of a flexible material such as a soft synthetic resin, the injection pipe 3 can be used by being inserted into a rigid guide pipe 8 which is sequentially connected as shown in FIG. Therefore, there is an advantage that the feeding work can be performed at a low position and the workability is good, and the product can be rolled and handled during transportation.

Next, in the second embodiment shown in FIG. 3, after drilling with the boring rod 1 (a), the water swivel of the drilling water at the time of drilling is replaced with a swivel having a seal portion 9 and the injection pipe 3 is drilled.
Is inserted to the tip of the boring rod 1 (b). Then, while pulling up the injection tube 3 together with the boring rod 1, the liquid A is injected into the injection tube 3 and the boring rod 1
The liquid B is pumped into the inside, and the grout S _{1 in} which the liquid A and the liquid B are mixed and mixed at the tip is injected into the drilling marks 4 (c), and the first step is completed. Injection tube 3 as
The while pressed into the consolidation of grout S _1, the infusion tube 3 is obtained so as to inject by pumping grout S ₂ were mixed liquid A and B 'solution.

In this second embodiment, while pulling the injector tube 3 simultaneously with the boring rod 1 during retraction infusion of the first step is injected A, grout S ₁ of B two-liquid mixing, and A in the second step,
In that injecting grout S ₂ of B 'two-liquid mixing, which differs from the first embodiment.

The grouts S ₁ and S ₂ in this case are shown in Table 1 below.
Use grout with the composition listed in.

FIG. 4 shows a schematic diagram of the process of the present invention.
After the final step is completed by-advance step implantation as shown in FIG. (E), it is also possible to perform additional injection of grout S ₂ in being pulled up the inlet tube 3.

Further, as shown in FIG. 5, after the injection pipe 3 is pulled out (a), the injection pipe 3 can be inserted again into the drawing trace and re-injected by forward injection (b). The filling of the trace is optional, but when filling, an appropriate one is used as the solidification strength of the filled grout.

In this way, after taking all steps into consideration such as re-injection, the boring rod 1 is pulled out and collected.

Hereinafter, the present invention will be described in detail based on specific experimental examples.

Experimental Example 1 As a boring rod 1, as shown in FIG. 6, the tip between the inner and outer pipes was closed with a bottom plate 10, and a double pipe rod having a communication hole 11 in the inner pipe was used. As shown in Fig. 7, after drilling three holes at a pitch of 1m to a depth of 5m, while gradually pulling up to a depth of 2m, liquid A is supplied from the inner flow path and liquid B is supplied from the outer flow path and merged at the tip. The grout S ₁ shown in Table 1 of the attached sheet consisting of the mixed A + B liquid was injected into the drilling trace 4 (first step).

In this injection process, the injection length per line is 3 m
It was divided into 6 steps of 50 cm, and 70 injections were performed per step. At the final step, the boring rod 1 was pulled up to a depth of 2 m and a total of 420 injections were made in a 3 m drilling mark 4.

 The soil was sandy and between 3 and 4 m deep was gravel.

Next, the water swivel at the top of the boring rod 1 is removed, and the injection pipe 3 is inserted into the inner pipe and advanced by human power to press the tip into the consolidated body of the grout S ₁ , and from the lower end of the boring rod 1 When you extend 50 cm,
Liquid A is pumped from one of the Y-tubes at the rear end of the injection pipe 3 and liquid B'is pumped from the other end, and is mixed and mixed in the inside of the injection pipe A +
Injection was started grout S ₂ shown in Exhibit Table 1 consisting of B 'solution (second step).

In this injection step, the injection tube 3 was sequentially press-fitted and advanced, and a total of 480 injections were made at 80 (16 / min) per step for six steps with a step length of 50 cm.

 Then, the same process was repeated for the other two holes.

Experimental Example 2 Performed side by side with Experiment 1 and the drilling, improvement depth, total injection amount, and construction procedure were the same, but the injection amounts in the first and second steps were changed as follows, Three types of grout S ₂ -I listed in Appendix ₂ as grout S _{2 in} two steps
(A liquid + B solution), S ₂ -II (A liquid + B 'solution), S ₂ -III
(Solution A + Solution B ”) was used together.

First step (retraction type injection) S ₁ (A + B) 10 × 6 steps = 60 Second step (forward type injection) S ₂ −I (A + B) 50 × 4 steps = 560 S ₂ −II (A + B ′) 90 × 4 steps = 560 S ₂ -III (A + B ″) 50 × 2 steps = 280 S ₂ −II (A + B ′) 90 × 2 steps = 280 That is, in Experiment 1, the solution type flashing at the time of retreat injection in the first step. 70% grout S ₁ (solution A + solution B) per step
In contrast to the injection, in Experiment 2, it was kept as low as 10 per step to the extent that the collapse of the hole wall of the drilling trace 4 could be prevented to a minimum.

In addition, in Experiment 1, the grout during the forward injection of the second step
Although slow binding grout solution type as S ₂ and (A liquid + B 'solution) was for a single first Madokayui grout (S ₂ -I, S ₂ -III) at each step in the experiment 2 after injecting , followed by injecting a slow-setting property grout (S ₂ -II), between particular depth 3 to 4 m 2
Step fraction is to hit the gravel soil, after the initial injection of a suspension-type Madokayui grout (S ₂ -III), and subsequently injecting a slow binding grout solution type (S ₂ -II).

The switching between the liquid B, the liquid B 'and the liquid B "in the forward injection was carried out by suction grout pump.

Since the flexible hard pipe used for the injection pipe 3 had a relatively short overall length of 10 m, it could be used as a single pipe to inject not only loose grout but also flash grout.

In this experiment, the injection pipe 3 was press-fitted manually because the improvement range was small, but in actual construction, it is desirable to mechanically automate it by using a mechanical press-fitting means such as a press-fitting jack or a pinching feed roller device.

Results and considerations of Experiments 1 and 2 The injection effect of Experiments 1 and 2 was visually observed during shaft excavation, but in the second step, the so-called forward type, in which the injection position was sequentially moved from the upper layer to the lower layer, By performing the injection, the tendency of the grout to easily deviate upward is suppressed,
Grout penetration between the injection holes interfered with each other, and good results were obtained.

In this experiment, both the first and second steps were performed in a stepwise manner with one step length of 0.5 m. However, it is also possible to perform the non-step and slow and continuous forward or backward injection.

In this experiment, since the grout S ₁ used for the retreat type injection as the first step was a water glass solution type, the homogel strength at the time of press-fitting the injection pipe 3 in the second step was uniaxially compressed. The strength was as small as about 0.5 kg / cm ² and it was suitable because it could be easily press-fitted.

Furthermore, the grouts S ₁ and S used in the first step and the second step
₂ and the combination thereof are exemplarily shown in Experiments 1 and 2 of this time.
Of course, the present invention is not limited to this. For example, a loose grout may be used at the time of the injection in the first step, a suspension type may be used in addition to the solution type, or these may be used in combination.

However, especially when using a suspension type grout, it is recommended to use it within the strength range where the injection pipe can be pressed in after knowing the change over time of the consolidation strength and strength development, such as the presence and content of the cement component. is necessary. The strength of the injection pipe 3 that can be press-fitted is about 2-3 kg / cm at the time of press-fitting (uniaxial compressive strength).
It is about ² and preferably within 1 kg / cm ² .

Also, grout S ₂ used in the second step, suspended or solution-type or a combination of the both in the slow-setting property.

Quick-setting, suspension or solution type or a combination of both.

Combination of suspension type with slow setting and solution type with instant setting.

Combination of solution type with quick setting and solution type with slow setting.

Combination of suspension type with quick setting and solution type with slow setting.

Etc. can be used.

In addition, the grout used in the first step and the second step may be a water glass type, and in addition to the grout in the alkaline region as an example used in the present experiment, the grout in the neutral region and the grout in the acidic region may be used. These can be used, for example, grout in the alkaline region in the first step, grout in the neutral or acidic region in the second step, grout in the neutral or acidic region in the first step, grout in the alkaline region in the second step. Can be used, or the above combination in the second step can be used.

As the grout used in the first step and the second step, in addition to the water glass-based grout, an organic polymer-based grout, for example, a urethane (non-urethane) -based grout, a lignin-based grout, and the like can also be used.

In addition, any grout such as clay-based and cement-based grout can be used.

Furthermore, the construction method of the present invention can be applied not only downward but also in any direction such as upward or horizontal. Injection pressure at which the second step is carried out at 50 Kg / cm ² within If low pressure injection,
Also, high-pressure injection can be performed at 50 to 500 Kg / cm ² .

In short, according to the present invention, various grouts having any gel time are used alone or in combination, and the consolidation strength of the grout S ₁ filled in the drilling marks 4 in the first step is determined by the press-fitting of the injection pipe 3 performed in the second step. By moving the injection position in the forward direction, it is possible to inject the grout S ₂ into the surrounding ground around the consolidated body of the grout S ₁ while suppressing the tendency of the grout S ₂ to easily deviate upward. It is a feature.

[Effects of the Invention] As described above, according to the present invention, it is possible to perform a continuous injection using the advantage of the forward injection with the simplicity of the rod construction method, by rationally combining the backward injection and the forward injection. , It is possible to surely improve the target range, and surely achieve the preservation of water quality, the uplift of the ground surface, and the prevention of deformation of buildings and buried objects.

[Brief description of the drawings]

FIGS. 1 (a) to 1 (f) are longitudinal sectional views showing a first embodiment of the present invention in the order of steps, and FIGS. 2 (a) and 2 (b) show the use of a flexible injection tube used in the present invention. 3 (a) to 3 (e) are longitudinal sectional views showing a second embodiment of the present invention in the order of steps, and FIGS. 4 (a) to 4 (e) schematically show steps of the present invention. FIGS. 5 (a) to 5 (c) are longitudinal sectional views schematically showing other steps, and FIGS. 6 (a) to 6 (d) show steps of an experimental example of the present invention. , FIG. 7 is a plan view showing a drilling aspect of the experimental example. 1 ... boring rod, 2 ... bit, 3 ... injection pipe, 4 ... drilling marks, 5 ... check valve, 6 ... cone, 7 ...
... Injection hole, 8 ... Rigid guide tube, 9 ... Seal part, 10 ...
… Bottom plate, 11… Communication hole, S ₁ , S ₂ … Grout.

Claims (1)

(57) [Claims] 1. A first step of digging a boring rod into a ground to a predetermined depth, and then injecting grout under the following condition A) into the drilling trace while raising the boring rod to an arbitrary position; The injection tube inserted into the hollow part of the boring rod is pressed into the grout solidified in the first step and sequentially advanced while B)
A) The grout used in the first step is a solution-type or suspension-type flash-setting or slow-setting grout or a combination thereof. Alternatively, it is possible to prevent the hole-drilling wall from collapsing and maintain the consolidation strength such that the injection pipe in the second step can be press-fitted. B) The grout in the second step may be any of a solution-type or suspension-type flash-setting, slow-setting property, or a combination thereof, and the ground around the solidified grout in the first step may be used. That can be injected into. Grouting method characterized by the following.