JPH0932969A - Back filling method for buried object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a back filling method for a buried object wherein low-cost general mixture fluidized earth is used and besides placing of an upper layer bed, such as a road bed, is practicable within two hours after placing of a fluidized earth layer. SOLUTION: In a backfilling method for various buried objects 3 buried or built under a ground surface, a fluidized earth bed 1 formed of fluidized earth is placed at the periphery of the buried object 3. After a water curing layer 2 formed of a water curable material is formed on the fluidized earth bed 1, an upper bed part, such as a road bed 4, is placed on the water curing bed 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. It is necessary to perform sufficient compaction with a rammer. However, this conventional method has a problem in that filling with a backfill material and compaction by a 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.
No. 388 discloses a method in which water and a solidifying material are mixed with earth and sand, and the resulting soil is used for backfilling a buried pipe or the like as fluidized soil having 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.

On the other hand, in the road occupancy work on the city streets, which occupies the majority of the gas burial piping work, it is inevitable that the work will be carried out under the condition that the traffic will be opened on the same day. 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 according to the fluidized soil, the solidifying time can be shortened, but the cost becomes high, and
Since the compounding technology is also complicated, 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] In the backfilling method for backfilling various buried objects buried or constructed under the surface of the earth, the above-mentioned problems are solved by placing a fluidized soil layer made of fluidized soil around the buried object. And a water-cured layer made of a water-curable material is provided on the fluidized soil layer, and then an upper layer portion such as a roadbed is cast on the water-cured layer. It is solved by the backfilling method.

When a water-curable layer made of a water-curable material is provided on the fluidized soil layer, the water-cured layer absorbs the water in the upper portion of the fluidized soil layer and hardens by itself. Further, since the fluidized soil layer upper layer portion itself is also dehydrated, the inter-particle distance between them becomes closer, and the density increases and the layer hardens.

Therefore, the upper layer portion such as the roadbed can be placed within 2 hours after the fluidized soil layer is placed.

The water-curable material is one of cement, cement-based solidifying material, lime-based solidifying material, anhydrous gypsum, and hemihydrate gypsum.
In the case of the mixture containing at least one kind, the fluidized soil layer 1 is used because the mixture has a significantly higher early strength than other water-curable materials.
The upper layer portion such as the roadbed 4 can be placed on the upper portion in a shorter time.

If water is sprinkled on the water-curing layer after the water-curing layer is provided and before the upper layer is cast, the upper surface of the water-curing layer can be cured, so that the route can be shortened in a shorter time. It is possible to set the upper part such as the floor.

[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 the figure, 1 is a fluidized soil layer, 2 is a water hardening layer, 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, and 8 is a steel sheet pile for retaining soil. Is.

On the fluidized soil layer 1, water composed of a water-curable material such as cement, cement-based solidifying material, lime-based solidifying material, slag-based solidifying material, quicklime, gypsum, slag, fly ash or a mixture thereof. When the hardened layer 2 is provided, the water-hardened layer 2 absorbs water in the upper part of the fluidized soil layer and hardens itself. Further, the upper layer portion itself of the fluidized soil layer 1 is also dehydrated, the distance between the particles is reduced, the density is increased, and the fluidized soil layer is hardened. Therefore, the upper layer part such as the roadbed can be placed within 2 hours after the placement of the fluidized soil layer.

The water-curable material may be a mixture containing at least one of cement, cement-based solidifying material, lime-based solidifying material, anhydrous gypsum, and hemihydrate gypsum, which have stronger early strength, or the water-hardening layer 2 If water is sprinkled on the water-hardened layer 2 after the installation of the upper layer portion before placing the upper layer portion, it is possible to cast the upper layer portion such as the roadbed 4 on the fluidized soil layer 1 in a shorter time, which is desirable. .

[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. The strength of this fluidized soil layer is 0.03 kgf / cm ^{2 as a} cone index.
Where, about 30m thick on this fluidized soil layer
A water-hardening layer consisting of m super-high-strength cement was provided. Next, the strength of this water-cured layer is 1.5 kgf in Cone index.
When it reached / cm ² , mountain sand, which is a subgrade material, was put on the water-cured layer, compacted with a rammer, and pavement was constructed on it. At this time, the time from the completion of placing the fluidized soil layer to the introduction of the roadbed material is 1 hour, and the conventional construction time is 4 hours.
It was able to be greatly shortened compared to ~ 5 hours.

[0021]

[Table 1]

(Example 2) After arranging a gas pipe below the ground surface,
Fluidized soil similar to that used in Example 1 was filled around the gas pipe and flowed.
A fossil layer was placed. The strength of this fluidized soil layer is the cone index
0.02 kgf / cm^TwoBy the way, this flow
On the fossil layer, it is made of early-hardening hemihydrate gypsum with a thickness of about 50 mm.
A water-curable layer was provided. Then, add 1 part of water on this water hardening layer.
0 kg / m ^TwoThe strength of this water-cured layer is
Index of 1.2 kgf / cm^TwoBy the way,
Put mountain sand, which is a subgrade material, on the water-cured layer of
Compacted and built the pavement on it. At this time, flow
It takes 50 minutes from the end of pouring the soil layer to the introduction of the roadbed material.
there were.

[0023]

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,
It is possible to provide a backfilling method for buried objects that enables construction of an upper layer such as a roadbed within the time.

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 that the ground is not deteriorated at all.

[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 Water hardening layer 3 Buried objects such as gas pipe 4 Roadbed 5 Roadbed 6 Pavement 7 Ground surface 8 Steel sheet pile for earth retaining

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area E03F 3/06

Claims (3)

[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. A method for backfilling a buried object, comprising: providing a water-curable layer made of a water-curable material on the above, and then placing an upper layer portion such as a roadbed on the water-curable layer. 2. The method according to claim 1, wherein the water-curable material is a mixture containing at least one of cement, cement-based solidifying material, lime-based solidifying material, anhydrous gypsum, and hemihydrate gypsum. The method of backfilling the listed buried objects. 3. The embedding of the buried object according to claim 1, wherein after the water-curable layer is provided, water is sprayed on the water-curable layer before the upper layer portion is cast. Return method.