JPH0931951A - Backfilling method for buried objects - Google Patents

Abstract

PROBLEM TO BE SOLVED: To place an upper bed such as a subgrade within two hours after a superlasticized earth layer is placed by use of inexpensive superplasticized earth with a general combination ratio. SOLUTION: In a back-filling work filling back various embedded materials 3 buried or constructed under the ground surface, a superplasticized earth layer 1 comprising superplasticized earth is placed around the embedded material 3. After the strength of the superplasticized earth layer 1 biecomes 0.1kg/cm<3> or more in cone index, a plate 2 which is not buried in the superplasticized earth layer 1 is put thereon. An upper bed such as a subgrade 4 is placed on the plate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for backfilling underground objects such as gas pipes and communication cables.

[0002]

2. Description of the Related Art Conventionally, as a backfill material used when backfilling an underground buried object, in many cases, good quality sand or the like collected from another place is used. This is because excavated soil generated during the laying of underground buried objects is rarely suitable for backfill materials.

In recent years, from the viewpoints of depletion of high-quality mountain sand, which is a natural resource, environmental damage due to its extraction, traffic pollution due to its transportation, and disposal problems of excavated soil, excavated soil and construction unsuitable as backfill materials. There is a growing movement to effectively utilize sludge and other bad soil.

In the conventional backfilling method in which a backfill material such as high-quality sand is directly used, the backfill material is filled in a narrow portion such as a peripheral portion of the buried pipe without any gap in order to prevent depression after backfilling. Sufficient compaction with a rammer is required. However, this conventional method has a problem in that the filling of the backfill material and the compaction by the rammer are all manual work and cause noise and vibration.

Recently, instead of using a special backfill material such as the above-mentioned high quality mountain sand, excavated soil or cheap earth and sand generated when laying an embedded object is used, and the problems of the conventional method as described above. A fluidized backfilling method that can solve the problem has been developed and is partly in practical use. This method mixes water and solidified material with excavated soil and inexpensive earth and sand, gives the backfill material fluidity, fills narrow spaces around the buried pipe without gaps, and uses the effect of solidified material. It is intended to exhibit strength equal to or higher than that of the ground.

[0006] For example, Japanese Patent Laid-Open Nos. 63-233115, 1-312118, and 4-351.
In Japanese Patent No. 388, water and a solidifying material are mixed with ordinary earth and sand,
A method is disclosed for backfilling buried pipes and the like as fluidized soil with fluidity.

Further, in Japanese Patent Laid-Open No. 3-287909, the excavated soil is mixed with a solidifying material in advance, and the treated soil is transported to the backfill site, and water is poured into the treated soil while backfilling and vibration is applied. A method of fluidizing and completely filling the backfilled portion is disclosed.

[0008] On the other hand, in the road occupancy work on the city streets, which occupies most of the gas burial piping work, it is unavoidable to construct it under the condition of opening the traffic on the same day, and therefore a short-term backfilling work is essential. Has become. In particular, when the fluidized backfilling method as described above is used, it is required that the upper layer portion such as the roadbed can be placed within 2 hours after the fluidized soil layer is placed.

[0009]

However, with the fluidization backfilling method disclosed in the above-mentioned patent publication, the solidification time is as long as 4 to 5 hours, and it cannot be applied to road occupation work in urban areas.

If a special solidifying material is used in accordance with the fluidized soil, the solidifying time is shortened, but the cost is high and the compounding technique is complicated, so that strict quality control is required.

The present invention has been made in order to solve the above problems, and uses inexpensive general fluidized soil having a general composition, and moreover, within 2 hours after placing the fluidized soil layer, the upper layer of a roadbed or the like. It is an object of the present invention to provide a method for backfilling a buried object that enables the placement of parts.

[0012]

Means for Solving the Problems The inventors of the present invention have earnestly studied a construction method capable of backfilling an embedded object in a short time by using an inexpensive general fluidized soil, and as a result, solidification has progressed to some extent. We have found that the above problems can be solved by providing a disc-shaped material on the fluidized soil layer.

That is, the first invention according to claim 1
Refills various buried objects buried or constructed under the ground surface
In the backfilling method, if fluidized soil is
When a fluidized soil layer consisting of
Index of 0.1 kgf / cm ^TwoAfter the above,
A disc-like object that is not buried in the fluidized soil layer on the fluidized soil layer
And place the upper layer part such as a roadbed on the board.
This is a backfilling method for buried objects.

The strength of the fluidized soil layer has a cone index of 0.1 k.
If a disc-like material that is not buried in the fluidized soil layer is provided on the fluidized soil layer at the time of gf / cm ² or more, the strength of the fluidized soil layer is insufficient due to the load distribution effect. However, it can support the upper layers such as the roadbed. Therefore, the upper layer portion such as the roadbed can be placed on the fluidized soil layer in a short time within 2 hours after the completion of the placement of the fluidized soil layer. If the strength of the fluidized soil layer is less than 0.1 kgf / cm ² in terms of cone index, the strength of the fluidized soil layer is not sufficient. Therefore, even if a disc-like material is provided on the fluidized soil layer, the upper layer portion cannot be placed. Can not.

A second invention according to claim 2 relates to a backfilling method for buried objects similar to the first invention, characterized in that the board of the first invention is a foamable lightweight plate. It is a thing.

The use of the foamable lightweight plate facilitates transportation and processing, so that the upper layer portion such as a roadbed can be cast on the fluidized soil layer in a shorter time.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a method for backfilling buried objects according to the present invention. In FIG. 1, 1 is a fluidized soil layer, 2 is a plate-like object, 3 is a buried object such as a gas pipe, 4 is a roadbed, 5 is a roadbed, 6 is pavement, 7 is the ground surface, 8 is steel for retaining soil It's a sheet pile.

The strength of the fluidized soil layer 1 is 0.1 in terms of cone index.
At the time of kgf / cm ² or more, if the plasterboard, the plywood board, the tin plate, the thick vinyl sheet, or other plate-like material 2 that is not buried in the fluidized soil layer 1 is provided on the fluidized soil layer 1, Even if the strength of the fluidized soil layer 1 is insufficient due to the load distribution effect, the upper layer portion such as the roadbed 4 can be cast on the fluidized soil layer 1 within 2 hours after the completion of the fluidized soil layer casting. It will be possible.

If a foamable lightweight plate such as expanded polystyrene or expanded polyurethane is used as the board 2, it can be easily transported and processed, so that the subgrade 4 or the like is formed on the fluidized soil layer 1 in a shorter time. It is possible to set the upper layer part.

[0020]

【Example】

(Example 1) After arranging a gas pipe below the ground surface, fluidized soil having a general composition shown in Table 1 in which water and solidifying material are mixed with inexpensive earth and sand is filled around the gas pipe to form a fluidized soil layer. Was placed. When the strength of this fluidized soil layer reached 0.7 kgf / cm ² in terms of cone index, a 9 mm gypsum board was laid on the fluidized soil layer. Then, earth and sand as a roadbed material were put on this gypsum board and compacted by a rammer, and a pavement was constructed on it. At this time, the time from the completion of pouring the fluidized soil layer to the introduction of the roadbed material was 2 hours, which was significantly shorter than the conventional construction time of 4 to 5 hours.

[0021]

[Table 1]

(Example 2) After arranging a gas pipe below the ground surface,
The same fluidized soil as in Example 1 was filled around the gas pipe, and a fluidized soil layer was placed. When the strength of the fluidized soil layer reached 0.5 kgf / cm ² in terms of cone index, a 30 mm foamed polyurethane sheet was laid on the fluidized soil layer.
Next, earth and sand as a roadbed material was put on the foamed polyurethane sheet and compacted by a rammer, and a pavement was constructed on it. At this time, the time from the completion of pouring the fluidized soil layer to the introduction of the roadbed material was 1 hour and 40 minutes, which was significantly shorter than the conventional construction time.

(Example 3) After arranging the communication cable under the ground surface, the same fluidized soil as in Example 1 was filled around the communication cable, and a fluidized soil layer was cast. When the strength of this fluidized soil layer reached a cone index of 0.2 kgf / cm ² , a 30 mm styrofoam plate was laid on the fluidized soil layer. Next, earth and sand as a roadbed material was put on the styrofoam plate and compacted by a rammer, and a pavement was constructed on it. At this time, the time from the completion of the pouring of the fluidized soil layer to the introduction of the roadbed material was 1 hour and 10 minutes, which was significantly shorter than the conventional construction time.

[0024]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, even if an inexpensive fluidized soil having a general composition is used, the upper layer of a roadbed or the like can be formed within 2 hours after the completion of placing the fluidized soil layer. It is possible to provide a method for backfilling a buried object in which a part can be placed.

Further, when the backfilling method of the present invention is used, the backfilling work can be completed before the entire fluidized soil layer is completely solidified, so that the steel sheet pile for retaining soil can be easily pulled out, and After drawing the steel sheet pile, there is no gap between the fluidized soil layer and the ground, so no ground deterioration occurs.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a method for backfilling a buried object according to the present invention.

[Explanation of symbols]

 1 Fluidized soil layer 2 Board-like objects 3 Buried objects such as gas pipes 4 Roadbed 5 Roadbed 6 Pavement 7 Ground surface 8 Steel sheet pile for retaining soil

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16L 1/024

Claims (2)

[Claims] 1. In a backfilling method for backfilling various buried objects buried or constructed under the ground surface, a fluidized soil layer made of fluidized soil is cast around the buried object, and the fluidized soil layer is formed. After the strength of corn index becomes 0.1 kgf / cm ² or more, a disc-like material which is not buried in the fluidized soil layer is provided on the fluidized soil layer, and a subgrade is provided on the disc-shaped object. A method of backfilling buried objects, characterized by placing the upper layer of 2. The backfilling method for the buried object according to claim 1, wherein the plate-shaped object is a foamable lightweight plate.