JPH0633604B2 - How to throw in sand and water - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a method of introducing water into earth and sand, which is used for the construction of artificial islands, etc., in particular, the bending strength and the tensile strength are increased to improve the followability to deformation. It relates to the method of charging the soil and water.

<< Background of the Invention >> When constructing an artificial island on the water bottom of the sea, enclose the artificial island construction part with a sheet pile, and put earth and sand into the inside of it, and replace it with the internal water to complete the construction. ing.

However, in general earth and sand as input earth and sand, the particles separate and settle in water, so coarse particles settle and deposit first, and fine particles settle slowly and are suspended in water,
The artificial island ground formed is heterogeneous because it is deposited in the upper layer of the sediment, and the water content is high and extremely soft in the portion containing a large amount of fine grains. However, there was a problem that it was significantly polluted.

Therefore, the present inventors have previously developed a sand and sand composition obtained by mixing general clay with a binder and a hardening agent.

The binder in this earth and sand composition gives a caking property between earth and sand particles and secures a predetermined fluidity. The hardening agent is a material for solidifying earth and sand.

Therefore, when the sediment composition is poured into water, it sediments almost integrally without separating into pieces,
Since it is deposited in a homogeneous state and the amount of water taken up in water after a lapse of time is small, there is a point that it is possible to maintain a dense state with a small decrease in density.

Furthermore, by the curing action of the above-mentioned curing agent, the composition is solidified to a predetermined strength after being added, and becomes a strong solidified body.

<< Problems to be Solved by the Invention >> However, it has been found by the present inventors that this consolidated product has extremely high compressive strength but relatively low bending strength.

For example, in the artificial island construction method, as shown in FIGS. 1 (a) and (b), the water area is cut off with a sheet pile or the like, and the above-mentioned earth and sand composition is put into the inside of the cutoff 1 to solidify the solidified body. Two
Create an artificial island. After that, in order to form a substructure inside the artificial island 2, the solid body is excavated in a groove shape in the vertical direction.

In this case, the muddy water put in the groove 3 for stabilizing the groove wall applies a pressure in the direction of expanding the solidified body 2.

On the other hand, the water level outside the deadline 1 changes due to the ebb and flow of the tide.

At high tide, that is, when the deadline 1 is pressing the solidified body 2 inward, the pressure of the muddy water in the groove 3 and the solidified body 2 are balanced, and the groove wall is in a stable state.

However, as shown in FIGS. 2 (a) and 2 (b), when the water level decreases outward during tidal time, the deadline 1 bends outward,
As a result, the solidified body 2 receives a large bending force due to the muddy water pressure.

Therefore, if the bending strength of the solidified body 2 is small in such a state, the solidified body 2 cannot withstand the muddy water pressure, and is broken and cracked. As a result, the muddy water in the groove 3 escapes to the outside to pollute the water quality, and it becomes difficult to keep the groove wall stable.

The present invention solves the above problems, and an object of the present invention is to increase the bending tensile strength during consolidation of this type of earth and sand composition to prevent problems such as the aforementioned collapse of the groove wall. .

<< Means for Solving Problems >> In order to achieve the above object, the present invention relates to a method of enclosing a construction area of an underwater structure such as an artificial island, and pouring earth and sand into the interior of the area, by binding the earth and sand to the earth and sand. It is characterized in that the agent, the curing agent and the fibrous material are mixed and charged into the formation area.

<< Working >> The entanglement effect obtained by mixing a large number of fibers in the solidified body increases the tensile strength of the solidified body itself according to the tensile strength of the fiber and also increases the bending strength.

<< Summary of the Invention >> First, the earth and sand composition according to the present invention gives a caking property between earth and sand and particles of the earth and sand, and cures between a caking agent that secures a predetermined fluidity, a caking agent and earth particles. It is composed of a hardening agent for consolidating this and a fibrous material which gives a predetermined tensile strength after consolidating the earth and sand composition by being mixed in the inside thereof in an appropriate volume ratio. At that time, if the amount of water contained in the earth and sand is not sufficient to secure a predetermined fluidity, water (seawater may be used) is added.

The binder is made of water-soluble natural, semi-synthetic or synthetic polymer, and has a function of separating each particle by a kind of pasty substance and preventing water from being taken in.

Explaining the binder concretely, examples of water-soluble natural polymers include various starches, konjac, fungus, agar, sodium alginate, troloy mallow, tragone gum, gum arabic, dextrin, levan, glue, gelatin, casein, collagen and the like. Is.

Examples of water-soluble semi-synthetic polymers are viscose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, soluble starch, carboxymethyl starch, dialdehyde starch and the like.

Examples of the water-soluble synthetic polymer include polyvinyl alcohol, sodium polyacrylate, polyacrylamide, polyethylene oxide and the like.

The hardening agent has a function of hardening the earth and sand composition after being added, stabilizing the substance, and improving the compressive strength.

This hardener is used for ordinary Portland cement, blast furnace cement, fly ash cement, other cement materials,
Alternatively, it is one or a combination selected from lime-based materials such as slaked lime or asphalt-based materials, blast furnace slag-based materials, and coal ash-based materials.

The fibrous material has a function of imparting appropriate tensile strength by the effect of entanglement, in which the composition is dispersed in the solidified state of the composition by the above-mentioned earth and sand, the binder and the curing agent.

More specifically, carbon steel fiber, metal fiber such as stainless fiber, inorganic fiber such as glass fiber, aspest fiber, alumina fiber, organic fiber such as vinylon fiber and polypropylene fiber, carbon fiber, aramid fiber, etc. For example, fibers for reinforcing materials are used.

Next, a preferable blending ratio of the above materials will be described.

First, the mixing ratio of the binder and the hardening agent to the earth and sand is 10% by weight in consideration of the economical efficiency and the degree of achievement of the effect.
0.5 to 5 parts by weight of binder and 50 to 50 parts by weight of curing agent
The most preferable result is 300 parts.

Next, the fiber material is a factor in achieving the effect due to the function of the fiber diameter and the fiber length. First, the fiber diameter is several μm to several mm, and the fiber length is in the range of several mm to several cm. Is preferred. It has been found that it is preferable to mix the mixed amount in a volume ratio of 5 to 50 parts with respect to 1000 parts (volume) of the composition composed of the earth and sand, the binder and the curing agent.

The above-mentioned earth and sand composition containing a fiber material is suitable for various applications such as embankment on the water bottom in addition to the artificial island construction shown in FIG. 1, and when the constructed ground is particularly required to have tensile strength. Used.

<< Effects of the Invention >> As described above, after solidification of the earth and sand composition according to the present invention, the fiber itself dispersed and blended in a state of being entangled in the hitting portion has a large tensile resistance to the solidified body itself. In addition, for example, the bending strength and the toughness, which can sufficiently withstand the bending force due to the mud pressure in the groove as shown in FIGS. 2 (a) and 2 (b), are imparted.

<< Examples >> The compressive strength and the bending strength of the samples A, B, and C, which were mixed in the soil having the properties shown in Table 1 below at the mixing ratios shown in Table 2, were compared.

As a result, it was confirmed that the compressive strength and bending strength shown in the graphs of FIGS. 3 and 4 could be obtained.

In the figure, the compressive strengths of the sample A having no fibrous material and the samples B and C to which 1 part and 2 parts of fiber are added are almost the same, but as shown in FIG. It was found that both the strength and the amount of deflection increased, and it was confirmed that the toughness also increased.

It is needless to say that the optimum material combination and its composition can be obtained by repeating the experiments with various combinations even if the materials and other compositions are other than those in the above examples.

[Brief description of drawings]

1 (a) and 1 (b) are a plan view and a cross-sectional view showing an artificial island, and FIGS. 2 (a) and 2 (b) are a plan view and a cross-sectional view for explaining a problem at low tide of the artificial island. , Fig. 3,
FIG. 4 is a graph showing the results of measuring the compressive strength and bending strength with and without the addition of the fibrous material of the present invention.

Continuation of the front page (56) Reference JP-A-51-39939 (JP, A) JP-A-59-15119 (JP, A) JP-A-59-145830 (JP, A) JP-A-51-87324 (JP , A)

Claims (1)

[Claims] 1. Enclosing a construction area of an underwater structure such as an artificial island,
A method of pouring earth and sand into the interior thereof, wherein a binder, a curing agent and a fibrous material are mixed with the earth and sand and the mixture is put into the construction area.