JPS6249406B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an embankment construction method for soft ground. Regardless of the method used to improve soft ground such as coastal reclaimed land, reclaimed land, or swampland, it is necessary to first construct access roads for construction vehicles necessary to carry out the improvement work. There is. Sheet construction methods, ground surface solidification construction methods, etc. have been developed as means for constructing access roads on soft ground. The sheet method is a method in which a sheet-like material is laid on soft ground and embankment is performed on top of it to prevent the imported materials and the materials that make up the existing ground from mixing and turning into mud. This is an attempt to solidify the surface of soft ground itself. Each method has the advantage of being effective on extremely soft ground, but on the other hand, it has the disadvantage of requiring a large amount of materials and a long construction period, resulting in high costs. However, some of the so-called soft ground has a softness near the limit of whether wetland bulldozers can be operated, and is softer ground that is milder than the ultra-soft ground described above. In fact, what is often encountered during construction work is the latter type of so-called soft ground. Sheet construction methods and surface hardening methods are sometimes used to improve such soft ground, as in the case of ultra-soft ground, but these methods result in large economic losses. Also,
A construction method has been attempted in which a layer of lightweight embankment material is placed on soft ground, but the thin layer causes lateral flow and subsidence of the material as construction vehicles drive, making it difficult for the material to maintain the required running capacity. must be laminated in thick layers, which is poor in workability and economy. Therefore, in the case of such soft ground, it is desired to develop a more economical construction method, but at present no suitable method has been found. This invention was made in view of the above circumstances,
The purpose of this is to consolidate powder or hair-like materials such as industrial waste to form a rod-shaped tensile force resistor that has tensile resistance and penetration resistance, and then to place this on soft ground. The objective is to provide a construction method that is highly economical and can resist both the bending and tensile stress generated when construction vehicles pass by and the embankment material by spreading it irregularly and embanking on top of it. . Hereinafter, this invention will be explained in detail based on examples. A construction road with the bending and tensile strength necessary for driving a construction vehicle, especially a bulldozer, to bring in embankment materials by hand or a wetland bulldozer into a construction road area with soft ground (cone index of about 1.0 kg/cm ² ), as described below. A rod-shaped body of 30 to 50 cm thick is laid in an irregular direction, especially with respect to the horizontal plane, a part of it is dug into the above-mentioned soft ground to support horizontal displacement, and then a layer of 20 cm or more is laid on the surface. This is the construction of an embankment. The above rod-shaped body has a thickness of 20 to 100 mm and a length of 600 to 1500 mm.
When installing, the specific gravity must be lower than the bulk specific gravity of the soft ground (estimated at 1.3). That is, the weight of the bar itself is such that it does not sink into soft ground.In this invention, the following bar was formed and its bending tensile stress was determined.

【table】

【table】

[Table] All of these rod-shaped bodies satisfied the bending tensile stress (approximately 3.0 Kg/cm ² - experimental value) required for bulldozer operation. In addition, the thickness of the embankment after the rods are laid as described above is determined by whether it has sufficient resistance to bulldozer operation, and is determined by the bearing capacity coefficient of the ground (hereinafter abbreviated as K value). However, for practical purposes, 2.0Kg/cm ² or more is required. The relationship between the thickness of rods and embankments and the K value was determined using soft soil made by adding water to cohesive soil of 1.0 in a reinforced concrete test pit measuring 2.5 m in length, 4.0 m in width, and 1.8 m in depth.
m thickness to create soft ground with a cone index of 1.0 kg/cm ² or less. Bars were spread irregularly on this ground, then embankment was placed on top of it, and a flat plate loading experiment was conducted on the top of the embankment.The results were as follows.

【table】

[Table] In the above results, combinations that have a K value of 2.0Kg/cm ² or more required for bulldozer operation are shown in (Table 4) and (Table 5) with a bar laying thickness of 30 cm.
As described above, under the condition that the embankment thickness is 20 cm or more, a ground with sufficient running resistance can be obtained. In addition, the rod-shaped bodies described above (Table 1) to (Table 3) have a rough shape of 20 to 100 mm in thickness and 600 to 600 mm in length.
1500 mm, but if the thickness and length of the rod-shaped body are outside the above range, it will be difficult to handle, and workability such as transportation and irregular laying will deteriorate, and there will be waste and the tensile force resistor Functional efficiency decreases. The rod-shaped body may have an uneven surface, be non-linear in its overall length, or be a mixture of long and short lengths, and the cross-sectional shape of the rod-shaped body may be particularly circular. , is not limited to a rectangular shape, etc., and may be of an irregular shape. Furthermore, the materials used to manufacture the rod-like bodies are not only commercially available powders and hair-like bodies, but also
As mentioned above, even what is called industrial waste is sufficient, and this method is suitable for industrial waste (mine slag, dust, sludge, foundry waste sand, glass,
It also contributes to the effective use of waste, paper sludge, incineration ash, polymer scrap, etc.). As described in detail above, this invention is based on the artificially-manufactured material with a bulk specific gravity of 1.2 on the surface of soft ground.
Below, rod-shaped bodies with a length of 600 to 1,500 mm, a thickness of 20 to 100 mm, and a bending tensile stress of approximately 3.0 Kg/cm ² or more are laid irregularly to a thickness of 30 cm or more, and then 20
Embankment of cm or more is carried out, and the bearing capacity coefficient of the ground is 2.0.
Kg/cm ³ or more, when laying the rods on soft ground, there is no risk of the rods being buried under their own weight, and there is no need to arrange the rods regularly, but rather in a messy manner. By spreading it evenly, some of the rods will actively dig into the soft ground and overlap, preventing the rods from moving laterally or sinking due to the movement of construction vehicles. The bar-shaped body and the embankment material on top of it mesh in a convex-concave manner and are integrated, and there is no slippage between the embankment and the bar-shaped body, and the load of construction vehicles traveling on the embankment is evenly distributed to the bar-shaped body. It can be dispersed, exhibits excellent mechanical strength, and can significantly improve workability. In addition, rod-shaped bodies can be easily formed by simply drying industrial waste into a rod shape using an appropriate solidifying agent, and are low-cost. Has tensile resistance,
A construction road with a relatively thin embankment of about 20 to 30 cm and with the capacity to pass construction vehicles is determined by the cone index.
It has excellent effects such as being able to be formed in a short construction period even on soft ground of about 1.0Kg/ ^cm2 .

Claims (1)

[Claims] 1 Artificially manufactured on the surface of soft ground, with a bulk specific gravity of 1.2 or less, a length of 600 to 1500 mm, and a thickness of 20 mm.
~100mm, with a bending tensile stress of about 3.0Kg/ ^cm2 or more, are irregularly laid out to a thickness of 30cm or more,
An embankment construction method for soft ground, which is characterized by embanking 20 cm or more on top of it, and making the bearing capacity coefficient of the ground 2.0 Kg/cm ³ or more.