JPS6343531B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a grouting method, and more specifically to a curtain that constructs a water-blocking wall deep within a foundation rock in order to suppress seepage flow within the foundation rock. It concerns the grouting method.

<Prior Art> Most conventional curtain grouting methods use the principle of injection control as injecting a large amount of grout into the ground at a constant pressure.

Japanese Patent Publication No. 48-23377 exists as a grouting technique that takes into account the directivity of the grout injection direction.

This grouting technology involves installing protrusions on the outer circumferential surface of a nozzle that has a drilling function and a grout discharging function.The penetration of these protrusions creates cracks in the ground, and at the same time, the grout is discharged into the area where the ground has been cut open. This is a filling technique.

There is also Japanese Patent Application Laid-Open No. 48-57408, in which ground drilling and mixed liquid injection are simultaneously performed by injecting high-pressure fluid from within each hole drilled at appropriate intervals to neighboring holes.

<Problems to be Solved by the Present Invention> The conventional grouting techniques described above have the following problems.

(b) It is difficult to accurately understand the distribution of faults and joints (hereinafter referred to as ``cracks'') in the ground, and cracks often develop in many directions.

Therefore, in order to construct a continuous water-stop wall in the ground, a large amount of grout material is required in consideration of the amount of infiltration into the crack, which is uneconomical.

(b) Japanese Patent Publication No. 1973-23377 and Japanese Patent Application Laid-Open No. 1973-57408
With the technology in the publication, if a crack occurs in the hole or a geologically weak spot exists, the grout will penetrate into the crack or geologically weak spot, so the outflow of the grout material is avoided. I can't.

Furthermore, when grout penetrates into cracks or geologically weak areas, the pressure within the pores decreases, so cracks do not necessarily develop in the expected direction, making it difficult to control the direction of grout penetration. Have difficulty.

<Objective of the present invention> The present invention has been made in view of the above points, and provides a curtain grouting method that can control the direction of penetration of grout in hard ground such as bedrock, and can also minimize the outflow of grout. The purpose is to provide

<Structure of the present invention> Examples of the present invention will be described below, but first a jet nozzle used in the present construction method will be described.

An example of a jet nozzle 1 is shown in FIG.

This jet nozzle 1 has a water passage 12 continuous to the axis of its shaft portion 11, and the end thereof is connected to the shaft portion 11.
It has an injection path 13 formed by branching in a direction perpendicular to the axis.

The terminal end of each injection passage 13 is exposed on the outer peripheral surface of the jet nozzle 1 and forms an injection port 14.

Each injection path 13 can be provided in a straight line at 180 degrees as shown in FIG. 1, or in an L-shape at a certain angle as shown in FIG. A common feature is that the injection port 14 is opened in a direction intersecting the axis of the water passage 12.

<Effect> Next, the construction method will be explained.

(B) Drilling of grout holes (Figs. 3 to 5) Grout holes 4 are bored at predetermined intervals along the planned construction location of the impermeable wall.

As a drilling means for the grout hole 4, a casing 7 having a drilling function at the tip as shown in FIG.
Drill the hole while preventing the hole wall from collapsing.

(b) Removal of the casing (Fig. 8) Insert the inner tube 6 into the casing 7 to the bottom.

The inner tube 6 is a tube that can withstand injection pressure and can be cut with jet water, and is made of, for example, vinyl chloride.

Next, leaving the inner tube 6 in place, only the casing 7 is pulled out.

After the casing is removed, a cylindrical space is formed between the inner tube 6 and the hole wall.

(c) Creating a protective wall (Figures 8 and 9) Fill the space formed between the outer periphery of the inner tube 6 and the grout hole 4 with concrete or other grout.

After the grout hardens, the inside of the internal tube 6 is bored.

As a result, a continuous protective wall 5 is formed between the endotube 6 and the hole wall.

(d) Opening the slit (Figures 3 to 5, 10) Next, insert the jet nozzle 1 described above to the bottom of the inner tube 6, and while jetting high-pressure jet water with the jet nozzle 14 directed toward the adjacent grout hole 4. Gently pull up jet nozzle 1.

The jet water injected from the jet nozzle 1 first penetrates the inner tube 6 and the protective wall 5 due to impact fracture, and then perforates the ground over a certain length.

As a result, a slit 3 is opened that is continuous in the longitudinal direction and communicates with the internal intubation tube 6.

Since this slit 3 serves as a foothold for determining the injection direction of grout material, which will be described later, the total length of the slit 3 is equal to
It does not have to be long enough to reach .

In the manner described above, a slit 3 is formed in each grout hole 4 as shown in FIGS. 4 and 5.

In addition, in FIGS. 3 to 5, the protective wall 5 is omitted for illustration purposes.

(e) Grouting work (Fig. 11) When grouting material for constructing an underground wall is filled into the inner tube 6 with the entrance of the grouting hole 4 blocked with a gasket, etc., the filling pressure of the grouting material is concentrated in the slit 3. A crack develops from the tip of the slit 3 along the construction direction of the underground wall.

This means that even if there is a geological weak point 9 such as a fault or joint around the grout hole 4, it is covered by the protective wall 5 and the pressure of the grout material is absorbed by the geological weak point 9.
This is because the filling pressure of the grouting material is concentrated at the tip of the slit 3, avoiding direct action on the grouting material.

Each grout hole 4 is filled with grout material to construct a continuous water-blocking wall.

<Other Embodiments 1> Especially in the case of hard ground, it is also possible to employ blasting or high-pressure gas as a means for developing cracks in the slits 3.

The fixing and steps for constructing the protective wall 5 in the grout hole 4 before opening the slit 3 are the same as in the previous embodiment.

In this embodiment, the slits 3 are opened using blasting or high-pressure gas, and then filled with grout to construct a continuous wall having water-blocking properties.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be expected.

(b) A cylindrical protective wall is constructed inside the grout hole to cover the hole wall, and a slit is forcibly cut in the direction of constructing the impermeable wall, and then filled with grout material.

Therefore, the protective wall covers the cracks that occur in the hole and prevents the grout from entering the cracks, and also concentrates the filling pressure of the filled grout into the slit without transmitting it to the geological weak point. Using the slits as footholds, cracks can develop in the direction of constructing the impermeable wall.

Therefore, it is possible to construct a continuous wall with high water-shielding effect in hard rock.

(b) The protective wall serves to cover cracks occurring in the hole to prevent grout from penetrating into the cracks, and also to concentrate the filling pressure of the grout in the direction of cutting the slit.

Therefore, it is possible to prevent excess grout from flowing out and to make effective use of the filler, and also to make effective use of grout pressure.

[Brief explanation of the drawing]

Figures 1 and 2: An explanatory diagram of one embodiment of the jet nozzle, Figure 3: Plan view of the construction arrangement, Figure 4: An explanatory diagram of the shape of the grout hole, Figure 5: Side view of the construction arrangement, Figures 6 to 10 Figure: An explanatory diagram of the construction state according to the present invention. Figure 11: An explanatory diagram of the filling of grout material. 1: Jet nozzle, 3: Slit, 4: Grout hole, 5: Protective wall, 6: Internal tube.

Claims (1)

[Claims] 1. Grout holes are bored at appropriate intervals, a protective wall is formed around the inner periphery of the grout holes, and high-pressure water is injected from within each grout hole toward the adjacent grout holes. Vertical slits are created by cutting into the ground together with the protection wall, and then grout is filled under pressure into the grout holes, and the filling pressure of the grout holes is concentrated on the slits, causing cracks to develop in the extending direction of the slits. Curtain grout method.