JPH0427014A - Construction method of underground structure framework - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of constructing an underground structure frame.

<Conventional technology> When submerging the framework of an underground structure such as a caisson, conventionally,
As shown in Fig. 4, a friction cut B (approximately 5 cra) is provided on the outer circumferential surface of the caisson a, and a gap C is secured between the ground and the outer circumferential surface of the caisson a to reduce surface frictional resistance. This makes sinking easier.

On the other hand, after the caisson a is completely submerged, it is necessary to increase the circumferential frictional resistance and stabilize the structure, contrary to the case when the caisson a is submerged.

However, as described above, if there is a gap C between the earth and the outer circumferential surface of the caisson a, it becomes difficult to ensure the required circumferential surface frictional resistance.

<Problems to be solved by the present invention> Therefore, in the past, an injection hole d was bored in the caisson a, and mortar e etc. was filled into the cavity C through the injection hole d to suppress the subsidence of the surrounding ground. Attempts have been made to restore circumferential frictional resistance.

However, with this injection method, the mortar e, etc. enters only into the large voids in the ground, and it is difficult to fill the entire void C uniformly, so there are cases where the effect of injecting the mortar e, etc. is not sufficient. There is.

Therefore, it was impossible to ensure sufficient circumferential frictional resistance, and the structure lacked reliability in terms of design.

In addition, until caisson a is sunk to a predetermined depth, cavity C is essential for the sake of sinking, and this causes loosening of the surrounding ground and causes continuous subsidence. .

<Object of the present invention> The present invention has been made to solve the above-mentioned problems, so that it is possible to reduce the circumferential frictional resistance when submerging the framework of an underground structure, and furthermore, after the submergence is completed, the circumferential surface friction resistance can be reduced. The purpose of the present invention is to provide a method for constructing an underground structure frame that can increase surface friction resistance.

<Means for solving the problem> That is, the present invention provides a flange protruding from the outer periphery of the lower end of an underground structure frame, and connects the structure between the outer surface of the side wall above the flange and the ground. In this method, a continuous pipe is inserted from the top surface of the flange to the above-ground part in the cavity, and granules are introduced into the cavity to prevent the structure from settling. In this case, after the structure is settled to a predetermined depth by applying vibration to the granular material through the tube, the solidifying material is injected from the lower end of the tube while pulling out the tube. This is a method for constructing the framework of an underground structure.

<Description of the present invention> The present invention will be explained in detail below.

<A> Shape of structure skeleton As the underground structure skeleton, caisson 1 as shown in Figure 1 is used.
This will be explained using an example.

The caisson 1 is a box made up of a side wall 11 and a bottom plate 12, and a flange 13 is provided on the outer periphery of the lower end of the caisson 1 to project horizontally.

This flange portion 13 has a larger horizontal protrusion width than the conventional friction cut.

Therefore, when the caisson 1 is sunk, a gap 14 having a wider width than before is formed between the outer peripheral surface of the side wall 11 and the ground 7, as shown in FIG.

Note that a cutting edge 15 is provided on the lower surface of the flange 13 in a protruding manner.

<Exposure> When the caisson 1 is to be sunk, the caisson 1 is sunk while ensuring the void 14 between the outer peripheral surface of the side wall 11 and the ground 7.

At this time, an appropriate number of double pipes 2 continuous from the upper surface of the flange part 13 to the above-ground part are inserted around the caisson 1 into the cavity 814, and the granular material is introduced.

For the granules, aggregate 3 such as crushed stone or artificial lightweight aggregate is used.

The double pipe 2 has an inner pipe 22 with an injection hole 21 provided at an arbitrary position.
and an outer tube 23.

Note that the outer circumferential surface of the outer tube 23 may be processed to have a different shape, such as a concave-convex spear, in order to improve the transmission rate of vibrations to the aggregate 3.

By using the single pipe 2, reliability can be ensured when injecting the consolidation material 5, and it is also possible to perform partial injection or secondary injection using a packer, etc. .

This leads to increased reliability as a structure.

Note that the vibration and injection work can be performed using a single tube, but in this case, a thick and strong tube is used.

<C> When the vibrating caisson 1 is settling, the outer tube 23 of the double tube 2 is vibrated and the vibration is transmitted to the aggregate 3.

As a result, the entire aggregate 3 filled in the cavity 14 vibrates, and the filling density of the aggregate 3 can be made constant.

At this time, the earth pressure of the surrounding ground 7 acts on the outer peripheral surface of the caisson 1 through the aggregate 3, but since the aggregate 3 is in a fluid state due to vibration, there is a gap between the outer peripheral surface of the caisson 1 and the aggregate 3. frictional resistance is reduced.

Note that, as shown in FIG. 1, depending on the ground conditions, the sedimentation work can be performed while interposing a perforated sheet 4 such as a nonwoven fabric between the earth 7 and the aggregate 3.

This makes it possible to prevent groundwater and clay particles from entering the aggregate 3 from the surrounding ground 7, thereby increasing the reliability of the structure.

In addition, as shown in FIG.
It is also possible to perform settling while installing reinforcing bars 6, dowel bars 61, etc. inside.

<2> Injection of consolidation material After the caisson 1 has settled to a predetermined depth, the outer pipe 2
3, the cavity 14 is filled with a solidifying material 5 such as mortar or cement milk through the injection hole 21 of the inner tube 22.

At this time, since the consolidation material 5 is gradually injected upward from the lower part of the cavity 14, it is possible to reliably fill the gaps between the aggregates 3 without leaving any gaps.

By solidifying the consolidating material 5 and adhering to and integrating with the surrounding ground 7, the circumferential frictional resistance can be increased.

In addition, since the aggregate 3 is vibrated and compacted evenly, the circumferential frictional resistance is further increased.

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

<A> The present invention secures a void between the outer circumferential surface of the framework of an underground structure such as a caisson and the ground, pours aggregate, etc. into this void, and applies vibration to the aggregate. This is a type of underground construction.

Therefore, the aggregate becomes fluid due to the vibration, and the frictional resistance between the outer peripheral surface of the structure and the aggregate is reduced.

Therefore, the structure can be deposited very easily.

<Exposure> Furthermore, according to the present invention, after a structure has been settled to a predetermined depth, it is possible to reliably fill the structure with a consolidating material without leaving any voids between the aggregates.

Therefore, by solidifying the consolidating material and adhering to and integrating with the surrounding ground, it is possible to increase the circumferential frictional resistance.

Therefore, the reliability of the underground structure as a structure can be improved.

<C> In the past, since sufficient circumferential frictional resistance could not be obtained after sinking, the shape of the structure frame had to be made larger than necessary, which was uneconomical.

However, in the case of the present invention, it is possible to reduce the peripheral surface frictional resistance at the time of sinking, and it is also possible to increase the peripheral surface frictional resistance after sinking.

Therefore, the structure frame can be made economically sized and lightweight.

[Brief explanation of drawings]

Figure 1: An explanatory diagram when the structure frame is submerged. Figure 2: An explanatory diagram of the state in which consolidation material is injected into the void. Figure 3: An explanatory diagram when installing reinforcing bars, etc. in the void. Fourth. Figure: Illustration of conventional technology

Claims (1)

[Claims] (1) A method in which a flange is provided protruding from the outer periphery of the lower end of an underground structure frame, and the structure is sunk while ensuring a gap between the outer surface of the side wall above the flange and the ground, A tube that continues from the upper surface of the flange to the above-ground part is inserted into the cavity, and a granular material is introduced into the cavity, and when the structure settles, the granular material is introduced through the tube. Construction of an underground structure frame, characterized in that after the structure is submerged to a predetermined depth by applying vibrations to the structure, a consolidating material is injected from the lower end of the pipe while pulling out the pipe. Method.