JPH0412328B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a grouting method.

(Prior Art) A grouting method is generally used to reinforce the ground at a dam site when constructing a dam on weak ground.

That is, FIG. 7 shows a conventional example of this type. First, as shown in FIG. A hole is drilled in the weak ground G while positively circulating as shown by the arrow, and when this hole reaches a predetermined depth and the total length l of the grout, the boring rod 5' is pulled out and as shown in the diagram, Next, install the injection pipe 10' to the bottom of the drilling hole,
A packer 11' is installed at the top of the excavation hole, and an injection agent 14' such as cement milk is injected under pressure through a grout pump 12', and the injection agent 14' is injected into the gap g' in the ground as shown by the arrow. The ground is reinforced or water-blocked.

However, in this case, after the drilling is completed, the boring rod 5' is pulled out from the hole and the injection pipe 1 is
In the process between inserting grout 0' and injecting cement milk, the hole wall of the drilled hole may collapse in weak ground, and this has the disadvantage that grout cannot be injected into the gap g' at the dam site. I was getting used to it.

(Object of the Invention) The present invention was proposed in view of the above points, and its purpose is to fill a drilled hole with an aggregate that can be injected with grout when a boring rod is pulled out. Therefore, it is an object of the present invention to provide a grouting method in which grout can be injected into a void part while reliably preventing the collapse of a hole wall, and which can reinforce or block water from a weak part such as conglomerate.

(Structure of the Invention) Figures 1 to 6 sequentially show the steps of the grouting method according to an embodiment of the present invention.
The construction method will be explained.

First, a first step of drilling is performed in fragile ground G such as conglomerate through a boring rod 5 equipped with a drilling bit 4 while circulating fresh water 2 in a water tank ₁ (Fig. 1). reference). In addition, in the figure, 6 is a turntable of a known configuration, and 7 is a pump provided in the injection pipe 8.

After the completion of drilling in the first stage _l1 , while pulling out the boring rod 5, the aggregate 9 prepared in advance on the ground side is mixed with water and fed into the hole through the hollow part of the boring rod 5. Fill the aggregate 9 from the bottom of the hole to the hole head (see Figure 2). The aggregate 9 is preferably one that has voids between the aggregates 9 so that grout can be injected, is lightweight and easily crushed, and may be an artificial lightweight aggregate, a natural lightweight aggregate, or a by-product lightweight aggregate. The most suitable one is selected and used as appropriate.

After the boring rod 5 is completely pulled out, the injection pipe 10 is inserted into the upper part of the drilled hole, the packer 11 is attached, and the injection agent 14 such as cement milk in the water tank 13 is pumped through the grout pump 12.
is injected into the drilled hole under pressure. In this case, the hole is filled with aggregate 9 and the hole wall is supported by the aggregate 9, so it will not collapse. Also,
The injection agent 14 passes between each aggregate 9 and is injected into the ground gap g as shown by the arrow (third
(see figure). Note that 15 in the figure is a batcher.

After the first stage injection is completed, the hole in the first stage _l1 containing the aggregate 9 is rebored, and then the ground is bored in the second stage _l2 (see Fig. 4). Note that _G1 in the figure is a location where the injection has already been completed.

After the hole drilling in the second stage _l2 is completed, aggregate 9 is packed into the hole in this portion as explained above (see FIG. 5).

After the aggregate 9 is filled into the hole in the second stage _l2 , as explained above, an injection pipe is inserted into the upper part of _the hole in the second stage _l2 through the hole in the first stage l1. At the same time, a grout car 11 is installed, and a grouting agent is injected into the ground gap g via the grout pump 12 (see Fig. 6).

After the injection is completed, as explained above, the hole is rebored in the second stage _l2 , and the above steps are repeated to drill the hole to a predetermined depth.

(Effects of the Invention) As described above, according to the present invention, in the grouting method, when the boring rod that has drilled the hole is pulled out, the drilled hole is filled with aggregate and grout is injected. This method has the advantage of being able to inject grout into the voids at the dam site while reliably preventing collapse of the hole walls even in weak ground.

[Brief explanation of drawings]

1 to 6 are explanatory diagrams showing the process steps of the present invention, and FIGS. 7A and 7B are conventional examples.

Claims (1)

[Claims] 1. A grouting method characterized by filling the hole with aggregate and injecting grout when pulling out the boring rod that has drilled the hole.