JPS63184607A - Stabilizing construction for surface layer for poor subsoil - Google Patents

Abstract

PURPOSE:To form a surface layer with less settlement at the time of working a load, on poor subsoil, by laying bag units with front and back sides connected at equal intervals, on the poor subsoil, and by pressing mixed substance with soil and cement, in the bag units. CONSTITUTION:Out of the sheets 1, 2 of nylon or the like permeating no particles of cement or the like, bag units 5 are formed; the front the back side sheets 1, 2 are connected together with coupling strips 3, 4 at equal intervals on the whole surface. After the bag units 5 are laid on poor subsoil 6, the mixture of the water bearing silt of field soil and cement is pressed in the bag units 5 and is cured. As a result, a surface layer with less settlement at the time of working a load can be formed, and filling 7 can be executed on a road on the upper section of the surface layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a surface stabilization method employed when forming vehicle access roads, embankments, etc. on soft ground such as a hydrous silt layer.

Conventional technology Conventionally, methods for stabilizing the surface layer of soft ground when carrying out civil engineering works such as embankments and road construction on soft ground include embankment, displacement, physical soil stabilization, and chemical soil stabilization. In addition to soil stabilization methods, we also use soda, rafts, mats, iron mesh,
A method of laying a sheet, etc. is used.

Problems to be Solved by the Invention Although various construction methods such as those mentioned above have been adopted in the past, a layer of hydrated silt as thick as that of Central America is formed over a vast area spanning hundreds of thousands of square meters. When constructing embankments or roads in all directions across soft ground, embankment methods and replacement methods will cause significant subsidence into the soft ground, making them impractical for practical use. In the traditional soil stabilization method, the required materials were press-fitted, and large-scale equipment had to be installed on site, making it unsuitable for practical use in terms of cost.

In addition, the construction method using soda, sheet, etc., has the disadvantage that when a large load is applied to the embankment or road, significant subsidence occurs, making it unusable.

For this reason, the present invention uses relatively small-scale equipment and a relatively small amount of materials to provide stable ground that has little subsidence and is less likely to tear or break even when a large load is applied to extremely soft ground such as a hydrous silt layer. It was invented for the purpose of providing a construction method that can easily form a surface layer in a short period of time.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention is made of two strong fabrics with a dense structure that are placed on soft ground such as a hydrous silt layer, and the front and back of the bag body are placed at equal intervals over the entire surface. After laying bags connected by connecting strips of a predetermined length, a solidifying material made by kneading cement into water-containing silt, which is soil forming soft ground, is press-fitted into the bags to form a surface layer, The structure is such that the embankment is filled after curing.

Function Since the present invention is the above-mentioned means, a fabric bag is formed in advance as a factory production work, and is laid on a construction surface of soft ground, and a concrete mixer is installed at the construction site to Soil such as hydrated silt and cement are kneaded at a ratio of lO to 1 to form an assimilation material, which is then press-fitted into the bag. At this time, since the soil forming the soft ground such as a hydrous silt layer has a high moisture content, it may be possible to easily mix it with cement without replenishing water.

The two fabrics on the front and back of the bag have a thickness of 30 cm to 50 cm, which corresponds to the surface layer thickness experimentally determined as the load-bearing thickness.
Since the bags are connected in a uniform manner over the entire surface by connecting strips so as to maintain a certain spacing, the bag is expanded to a predetermined thickness by press-fitting the solidifying material into the bag as described above.

This press-fitting of the solidified material can be done quickly and evenly into the bag by performing it through openings provided at appropriate locations in the bag.

After the assimilated material is filled into the bag, it is cured until it is completely solidified by cement to form a hardened surface layer, and then embankment is carried out on top of the hardened surface layer to complete the stabilization of the surface layer.

The surface layer formed by straining as described above is not a completely hardened layer, even though cement is used as a hardening agent.
The hardened layer is capable of elastic deformation to a certain degree, and the fabrics on the front and back sides of the bag made of strong fabric are located above and below the hardened layer, so that when a large load is applied, the piles of the front and back fabrics The tension, combined with the internal hardened layer, acts as a resistance force that tends to maintain the flat surface against the load, and the load is distributed over the entire surface layer. As a result, the sinking of the load acting surface is minimal, and the hardened layer There is almost no tearing or damage, and it is possible to maintain a nearly flat state that can withstand use for a long period of time.In addition to the bag and cement, the only materials used are soil formed from the soft ground at the site. The only mechanical equipment required on site is a concrete mixer and a press-feeding and press-in machine for the mixed materials, reducing costs and construction time.

Embodiment Figures 1 and 2 show an example of implementation, and the fabric is a strong woven fabric made of synthetic fibers such as polyester and nylon woven into a dense structure that does not allow particles such as silt and cement to pass through. At the same time, the front and back fabrics 1 and 2 are sewn together with connecting strips 3.4 of a predetermined length arranged at equal intervals over the entire surface.
The bag body 5 connected with
Lay it on the planned road surface.

Next, inside the concrete mixer that was brought to the site and installed,
Water-containing silt and cement from the site are added at a ratio of 10 steps, kneaded without water injection (in some cases with water injection) to form a solidifying material, and then immediately press-fitted into the bag body 5. In order to ensure that the solidifying material is evenly filled into the bag body 5, this press-fitting is performed through injection ports provided at multiple locations in the bag body 5, and after press-fitting, the injection ports are closed by sutures or other appropriate means. Obstruction.

As shown in FIG. 1, the bag body 5 maintains the thickness H defined by the connecting strips 3.4 and is in a bulging state between the connecting points.

After the above-mentioned solidifying material is press-fitted, it is cured until solidified, and embankment 7 is carried out to complete the construction of the road.

By carrying out the above steps sequentially for each section of road planned for construction, the construction work can be completed in a relatively short period of time.

The above-mentioned mixture of water-containing silt and cement becomes a shape-retaining body with some elasticity upon completion of solidification, and when a large load is applied, it deforms slightly elastically in the direction of the load, and although some cracks occur, the bag remains intact. Since it is covered with fabric 1.2 of No. 5, it will not tear apart greatly.

By the construction method of the present invention, as shown in Fig.
? , internal friction angle φ=0. The unit weight of the soil is 1.4, the depth is 15 m), the surface area of 20 m x 20 m is
An embankment 7 with a width W2 of lOm is formed in the center, forming a solidified layer of cm.
In addition to constructing road 8 where the
As shown in the figure, a sheet 1.2 of the same quality as the fabric 1.2 constituting the bag body 5 is laid adjacent to it in an area of 20 m x 20 m, and a road 9 is constructed using the sheet construction method with embankment 7. When used as a road for dump trucks to transport soil and as a regular construction road, the results shown in the table below were obtained.

The numerical values in the table are as shown in Figure 2). The measurements were taken uphill, and measurements were taken on Road 9 in the same manner.

Road surface subsidence on the fourth day in the table above.

When the amount of heaving is illustrated, the state in the case of the construction method of the present invention is shown in FIG. 3, and the state in the case of the comparative example of the conventional sheet construction method is shown in FIG. 4.

In other words, in the conventional sheet construction method, settlement of nearly 1 m occurs at the Nl2 point in the center of the road surface, and Na
50cm to 70cm at both points l and Na3.
In contrast, the construction method of the present invention has improved the NIL in the center of the road surface.
Only 2Lcm at 2 points, NILI, N on both sides of the road surface
At both points of A3 (・only 9 cm or 12 c
The ridge was only about 1.5 m wide, and there was no need to repair the road surface at all.

As has already been elucidated in the civil engineering field, the road surface support capacity achieved by the sheet construction method in the comparative example described above is due to the support capacity of the soft ground itself, the hammock-like support capacity of the center part of the sheet on both sides, and the support capacity of the sheet construction method. It is thought that this is due to the combined effects of the reaction force caused by the seat pressing down on the ground upheaval on both sides, and the buoyant support force generated in the part where the seat has sunk due to the load, but even so, the support force is weak, and As shown in Figure 4, significant subsidence occurs.

On the other hand, the reason why the road surface settlement is extremely small according to the construction method of the present invention is because it is filled with a mixture of soft soil such as hydrated silt and cement, as shown schematically in Figure 5.
When a load P is applied to the bag 10 that hardens, the bag 10 hardens while having some elasticity as described above.
At the same time, the front fabric 11 receives tension directed toward the point of load application as shown by arrow Q, and at the same time, the back fabric 12 receives tension directed outward from the point of load application as shown by arrow R. As a result, the bag The load p is distributed approximately evenly over the entire body 10, and the supporting force S of the ground acts evenly on the bag body 10, and the supporting force of the road surface in the conventional sheet construction method and the conventional Sodae method or This is presumed to be a result of the combined effect of the ground bearing capacity in the squid-and-tick method.

It has been confirmed that the height of the raised part 12 of the ground in the outer part of the bag body 10 shown in FIG. 5 is also several tens of centimeters lower than the raised part of the ground in various conventional construction methods.

Although the above-mentioned embodiment is an example of road construction, the same applies to the case of embankment.

The thickness of the bags 5 and 10 is selected from among various experimentally determined values depending on the supporting capacity of the soft ground, the magnitude of the loading load, and the like.

Effects The present invention has the above-described configuration 1, and as long as the bag body, cement, concrete mixer, and pressure conveying device produced in a factory in advance are transported to the construction site, water content at the construction site can be reduced. By simply making a mixture of soil from soft ground and cement and press-fitting it into the bag, it is possible to form a surface layer on soft ground that is significantly less likely to settle when a load is applied, resulting in cost savings and shorter construction times. .

Furthermore, according to the present invention, it is possible to form a surface layer with significantly less tearing and subsidence, so it is possible to construct roads, embankments, etc. that are unlikely to require repair over a long period of time, and various civil engineering works in areas with soft ground can be constructed. It is also possible to increase the possibility of construction work and shorten the total construction period in the area.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a road formed according to the present invention;
FIG. 2 is a schematic plan view of what is shown in FIG.
The figure is a line diagram showing the state of subsidence of a road formed by the conventional sheet construction method, and FIG. 5 is a schematic cross-sectional view showing the relationship between the load and the supporting capacity of the ground on the road formed by the present invention. 1.2: fabric, 3.4 = connecting strip, 5: bag body, 6: soft ground, 7: embankment. Patent applicant: Textile Civil Engineering Development Co., Ltd. Representative: Osamu Ichikawa Kodai
Tatsuya Endo Figure 2

Claims (1)

[Claims] After laying a bag body made of two strong fabrics with a dense structure and connecting the front and back sides of the bag body with connecting strips of a predetermined length arranged at equal intervals on the entire surface, the bag body is laid on a soft ground such as a hydrous silt layer. A method for stabilizing the surface layer of soft ground, which is characterized by forming a surface layer by press-fitting a solidifying material made by mixing cement into water-containing silt or the like, which is the soil for forming the soft ground, and filling it with earth after curing.