JP2865457B2 - Construction method of lightweight solidified soil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a lightweight solidified soil. More specifically, by mixing the soil, the solidifying material, and the gel-like resin particles that have been swollen by water absorption, improved workability by imparting high fluidity in the unsolidified state and weight reduction in the solidified state are achieved at the same time. The present invention relates to a method for creating a lightweight solidified soil. This lightweight solidified soil is, for example, a filler around structures in a soft ground zone,
Applicable to backfill material, embankment material, lightweight column material, etc.

[0002]

2. Description of the Related Art As a conventional representative solidified soil, there is a soil cement. This is defined as “soil that has been added to cement and mixed with soil and solidified by linking soil particles”, and is a stabilized soil with cement. Lime may be used instead of cement as a solidifying material. In the case of soil cement, generally 5-15% of cement in soil
Often mixed. Used for road subgrades and subgrades by rolling and compacting with rollers etc. at the optimal water content ratio, and for lining slopes and waterways by adding water to soil and cement to make it soft. There are cases.

[0003] Such stabilized soil with cement or the like hardens and changes the properties of cohesive soil as compared with untreated soil, so that the consistency (consistency) of the soil is improved or the soil quality is improved. High mechanical strength.

In recent years, when embankment is made on soft ground, in order to reduce the load of the embankment and reduce settlement,
The weight of the soil is being reduced. The typical construction methods and their advantages are as follows. A method of stacking styrofoam blocks, covering the outer surface with soil, and embedding lightly as a whole. This method is
There is an advantage that it is light and has good workability. Styrofoam beads are mixed with soil to reduce the weight. This method has an advantage that the lightweight property can be maintained only by mixing with water. A method in which cement and a foaming agent are mixed with fluidized mud and solidified to produce lightweight soil. Since this method is used as a filler or the like in a fluidized state, there is an advantage that pumping can be performed and mixing and filling can be performed even in a narrow place.

[0005]

In the case of soil cement, the amount of cement that usually has a uniaxial compressive strength of, for example, 30 kgf / cm ² is used, and although it has considerable strength, it cannot be reduced in weight. Therefore, it is difficult to apply to embankment on soft ground. In addition, the original method of use has poor fluidity and cannot be used to fill voids and the like, and water may be added in an excessive amount to increase fluidity, but then the volume change after solidification is large and void filling is insufficient. Becomes In any case, it cannot be applied to filling of voids and the like.

On the other hand, the conventional soil lightening has the following disadvantages. In the Styrofoam block construction method, lightweight soil is not originally used, but the Styrofoam block floats on the water, so it is not suitable for places lower than the groundwater level or where there is a possibility of flooding, and the material cost is high and the cost increases . In the case of the polystyrene beads mixed soil, the ordinary mixer cannot mix the soil and the polystyrene beads well, so that a special mixing device and a mixing method are required, and also the material cost is high and the cost is high. In the case of the foaming agent mixed soil, the air bubbles are crushed when pumped by a high pressure pump, and the void volume is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to use an ordinary mixing apparatus, to withstand high-pressure pumping, to have high fluidity, and to improve workability. It is an object of the present invention to provide a method capable of forming a good, lightweight and widely applicable solidified soil.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a soil, a solidifying material, and a gel-like resin powder which has been subjected to water absorption and expansion are mixed, and the mixture is transferred to a construction site in an unsolidified state to fill or fill. This is a method for forming a light-weight solidified soil in which the solidified material is left to stand naturally and solidified, and after solidification, the resinous powder particles are dried and shrunk to form cellular voids in the soil. If the soil used contains a lot of water in the form of mud, it is not necessary to add water,
An appropriate amount of water will be added depending on the water content.

The soil used here is local material, etc.
It may be soil that must be disposed of, such as excavated soil or dredged sludge. Regardless of whether it is natural or artificial, there is no restriction on the particle size. Therefore, a large amount of fine particles that cannot be used in a mortar may be contained. Unlike cement mortar, there is no restriction on the content of harmful substances or organic impurities. As the solidifying material, cement is mainly used, but lime or the like can also be used. The resin particles are particles of a water-swellable polymer material having a water absorption capacity of about ten to several hundred times, and may be a material of various conventionally known material series. Preferred examples of the material include a vinyl alcohol-acrylate copolymer. The type, particle size, addition ratio, and the like of these materials are appropriately selected according to use conditions, soil conditions, and the like.

[0010]

[Function] The water-swellable resin powder expands while retaining its original shape when it absorbs water, has a gel strength enough to maintain a firm shape, and behaves like a capsule that traps water. Present. In other words, it can be considered that the particles become elastic particles in the water-swelling state and exhibit incompressibility. The density is almost the same as that of water, the viscosity is low and the particles do not aggregate and the flowability is sufficiently high. Therefore, when the mixture is in an unsolidified state, the fluidity of the entire mixture is increased even if the amount of water is small due to the dispersing effect and the bearing effect of the gel-like resin powder particles that have absorbed water and expanded. Further, since the gel-like resin powder particles which have expanded and absorbed water are incompressible, they can sufficiently withstand high-pressure pumping.

When the above mixture is allowed to stand naturally in a predetermined state, a solidifying material such as cement reacts with surrounding water to bond and solidify soil particles. At that time, the resin particles shrink during drying. Since the solidified material has already connected the soil particles to each other to form a network, foamed voids are almost uniformly formed in the soil due to the shrinkage of the resin particles, and the resulting solidified soil is reduced in weight. You. The strength of the light-weight solidified soil obtained by the present invention is considerably lower than that of mortar or the like, and is about 1 to 5 kgf / cm ^{2 in} uniaxial compressive strength, and at most 10 kgf / cm ^2.
kgf / cm ² or less.

[0012]

FIG. 1 shows an example in which the method for forming a light-weight solidified soil according to the present invention is applied to filling a hollow portion by subsidence in a soft ground. A pile foundation 12 is cast on soft ground 10 and a footing 14 is provided. Subsidence of the soft ground 10 creates a gap between the ground and the footing 14. These voids are filled with the lightweight solidified soil 16 of the present invention. The light-weight solidified soil 16 is obtained by mixing soil, a solidified material, and a gel-like resin powder that has been swollen by water absorption, pumped and filled by a pump in an unsolidified state, and solidified by standing naturally. Since this type of filler is placed on the soft ground 10, it is necessary to reduce the weight in particular in consideration of measures such as ground settlement. Light-weight solidified soil obtained in the present invention, because of the formation of cellular voids in the soil due to drying shrinkage of the resin particles after solidification, the weight is reduced by that much,
The load on the soft ground 10 is reduced. In addition, it is required that during filling, the fluidity is high and the workability is good, and the volume change upon solidification is as small as possible. The light-weight solidified soil of the present invention, in an unsolidified state, can sufficiently withstand high-pressure pumping because the water-swelled, gel-like resin powder particles are incompressible, and a uniformly dispersed spherical gel. The fluidity is increased without excessively adding water due to the bearing action of the particles,
The filling operation can be performed efficiently. Since no excessive water is required, the volume change after solidification is extremely small, and good filling is possible.

FIG. 2 shows an example in which the method for forming a lightweight solidified soil according to the present invention is applied to backfill filling. In FIG. 2A, the lightweight solidified soil 16 is used for backfilling the pipeline 18 and in B, the lightweight solidified soil is used for backfilling a sheet pile or concrete retaining wall or various slope protection works (structures) 20. 16 is used. In the case of these backfilling, it is necessary to be able to be injected and filled even in a narrow place, and as with the filling of the subsidence, the fluidity when unsolidified is good, and the volume change when solidifying is small. It is required to be light after solidification. The light-weight solidified soil obtained by the present invention can satisfy all these requirements.

FIG. 3 shows an example in which the method for forming a lightweight solidified soil according to the present invention is applied to an embankment. In FIG. 3A, a mixture of the soil, the solidifying material, and the water-swelled gel-like resin particles is packed in a bag, and the bags are stacked. The mixture is solidified into a light-weight solidified soil 16
The embankment is formed by it. In addition, it can also be used as a banking material without packing. The embankment surface is subjected to slope protection by spraying a surface material 24 such as mortar or concrete. Of course, other slope protection works may be performed. In FIG. 3B, the lightweight blocks 26 are stacked,
It has a structure in which lightweight solidified soil 16 is filled inside.

FIG. 4 shows an example in which the lightweight solidified soil of the present invention is applied to a lightweight column. As shown in FIG. 4A, first, an excavation hole 30 is formed in the soft ground 10, and then, as shown in FIG. Under pressure. Then, the mixture is left to stand, and the mixture is solidified to form a lightweight column 32 made of lightweight solidified soil as shown in C. This lightweight column 32 can be used for improving soft ground.

[0016]

As described above, the present invention has a structure in which the soil, the solidifying material, and the gel-like resin particles which have been swollen by water absorption are mixed, so that the mixture has a high fluidity in an unsolidified state and a high-pressure pump. The workability is extremely good because it can be pumped at a pressure, and after solidification, the soil particles are combined by the solidifying material and a bubble-like void can be formed in the soil by the drying shrinkage of the resin powder, so that the lightweight solidified soil is Can be created.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view of a filling operation of a subsidence.

FIG. 2 is an explanatory view of backfill filling.

FIG. 3 is a diagram illustrating the construction of a lightweight embankment.

FIG. 4 is a diagram illustrating the construction of a lightweight column.

[Explanation of symbols]

 10 Soft ground 12 Pile foundation 14 Footing 16 Lightweight solidified soil

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Koji Higashioka 4-56, Kudankita, Chiyoda-ku, Tokyo Applied Geology Co., Ltd. (56) References JP-A-4-247112 (JP, A) JP-A-Hei 1-169015 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 3/00 C09K 17/10

Claims (4)

(57) [Claims] Claims: 1. A soil, a solidifying material, and a water-swelled gel-like resin powder and granules are mixed, and the mixture is transferred to a construction site in an unsolidified state, filled or embanked, and allowed to stand naturally to solidify. A method for forming a lightweight solidified soil, comprising forming a cellular void in soil by drying and shrinking the resin powder after solidification. 2. The method according to claim 1, wherein the mixture is pumped into or filled on a soft ground or a filling space in the soft ground. 3. The method of claim 1, wherein the mixture is pumped and bagged by pumping, and the light-weight solidified bag is stacked on soft ground to form a light-weight structure. 4. The method according to claim 1, wherein an excavation hole is provided in the soft ground, and the mixture is pumped to fill the excavation hole and solidify.