JP2001336145A - Fluidized treatment soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make construction sludge recyclable as a construction material such as backfill to increase a recycling ratio. SOLUTION: Mud slurry 6A containing water 6 or fine particles like clay and a solidifying agent 8 are mixed/agitated with adjusted sludge that construction sludge is treated and adjusted to have a specified water content to obtain the fluidized treatment soil. Further, the fluidized treatment soil can be also obtained by mixing/agitating mud slurry containing water or fine particle soil such as clay with improved soil formed by solidifying construction sludge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized soil obtained by fluidizing construction materials, more specifically, backfilling and backfilling of large structures such as subways and common ditches, backfilling of underground pipes, and underground space. TECHNICAL FIELD The present invention relates to a fluidized soil obtained by treating a construction material used for construction such as filling of water or a construction material used for construction of underwater embankment with fluidity.

[0002]

2. Description of the Related Art At present, a construction method of performing backfilling, backfilling, filling or the like using fluidized soil is being carried out. According to this method, the material flows into a narrow space due to fluidity, and thus is particularly suitable for, for example, backfilling or backfilling in a place where compaction is difficult.

Conventionally, as a fluidized soil, for example, as shown in JP-A-63-233115, water and a solidifying material (cement-based or lime-based) are added to soil (remaining construction soil) generated during construction work. Or fluidized by mixing, or as described in, for example, JP-A-7-82884, mixed muddy water containing clay or silt-like fine-grained soil with a solidified material is mixed with construction residual soil. is there.

[0004] By the way, when performing subway work or other construction work, for example, excavation work generates construction residual soil (generated soil), and at the same time, construction sludge. Construction sludge has a high water content (water content is about 55% or more), and its particles are fine and muddy, and cannot be reused as it is, and thus are treated as industrial waste.

[0005] The construction sludge has a possibility of being used as a resource, such as earth and sand, by performing a treatment such as soil improvement. However, a technology for recycling the construction sludge as a construction material such as backfilling has been proposed. The recycling rate of construction sludge is extremely low, because it has not been developed yet and the construction surplus soil has poor marketability, and most of it is disposed of by paying disposal costs. . In addition, securing final disposal sites and the like is expected to become increasingly difficult in the future, and urgent and aggressive measures are needed to improve the recycling rate of construction sludge.

[0006]

SUMMARY OF THE INVENTION In view of the above situation, the present invention makes it possible to recycle construction sludge as a construction material such as backfilling, thereby improving the recycling rate, and mining earth and sand in forests and the like. It is an object of the present invention to provide a new technology that can contribute to prevention of environmental destruction due to (eg, collection of mountain sand).

[0007]

Means for Solving the Problems In order to achieve the above object, one invention (first invention) of the present invention is a method of treating construction sludge to adjust the water content to a predetermined ratio.
It is characterized by mixing water and a solidifying material. In addition,
In this specification, "construction sludge" is used to include all sludge generated or discharged with construction foundation work and various other construction works.

In the present invention, water such as tap water or groundwater is used as the water. Further, as the solidifying material,
Examples include cement, cement-based solidification material, cement / lime composite-based solidification material, and lime.

Another aspect of the present invention (a second aspect) is characterized in that muddy water containing fine-grained soil such as clay is mixed in place of the water of the first aspect.

As the muddy water, muddy water generated or discharged during construction work (construction muddy water) can be used, but if necessary, natural clay can be added to water instead of the muddy water to dissolve it. It is also possible to mud and use this.
If necessary, clay can be added to the construction mud and used.

Another invention (third invention) of the present invention is characterized by mixing improved soil obtained by solidifying construction sludge with water and a solidified material. Another invention (fourth invention) of the present invention is characterized in that muddy water containing fine-grained soil such as clay is mixed instead of the water of the third invention.

[0012]

Embodiments of the present invention will be described below. The fluidized soil in one embodiment (Embodiment 1) of the present invention is obtained by mixing construction sludge with adjusted water content to a predetermined ratio and water and a solidifying material.

[0013] The construction sludge has a high moisture content, has fine particles and is muddy, and has a uniaxial compressive strength of about 0.5 kg / c.
m ² or less. The adjusted sludge is obtained by treating construction sludge and adjusting the water content to a predetermined ratio. In this case, if necessary, the sludge is passed through a mud screen or the like in an optional step to remove substances having a large particle size such as gravel mixed in the sludge. The ratio of the water content of the adjusted sludge is not particularly limited and can be adjusted according to the type of construction sludge.
The range is about 5% to about 65%. The sludge whose water content is adjusted as described above contains many fine particles (74 microns or less) and has a muddy shape (however, the fluidity is low).

The fluidized soil according to the first embodiment is obtained by mixing water and a solidified material at a predetermined ratio with the adjusted sludge. Specifically, a predetermined amount of water is mixed and prepared with the adjusted sludge, and a predetermined amount of a solidifying material (dissolved in water, the same applies hereinafter) is added, mixed, and stirred. The mixing ratio of water and solidified material to the adjusted sludge can be set according to the application, etc.
For example, with respect to the adjusted sludge 10, water is added in a range of about 2.5 to about 3.5, and the mixed composition 10 of the adjusted sludge and water is mixed with a solidified material (solid content of the solidified material dissolved in water, the same)
Ranges from about 0.6 to about 0.8. Thereby, it has fluidity and required uniaxial compressive strength (for example, 1.
^{0kg / cm 2 ~5.0kg / cm 2} ) has, and,
Breathing rate: 3% or less, flow value: about 160 to 30
Fluidized soil of about 0 mm can be produced.

Next, the method for producing the fluidized soil according to the first embodiment will be described more specifically with reference to the drawings. FIG. 1 is a block diagram schematically showing an example of a process for producing fluidized soil. In the same figure, 1 is construction sludge, 2 is a transport vehicle that collects and transports construction sludge 1, 3, 3
Denotes a receiving tank into which the sludge 1 is charged and stored, 4 denotes a mud screen, 5 denotes a mixing tank, 6 denotes water, 7 denotes a stirring tank, 8 denotes a solidified material such as cement, and 9 denotes a transport vehicle for shipping.

As shown in FIG. 1, construction sludge 1 collected by a transport vehicle 2 is put into a receiving tank 3 and stored therein, and the water content is adjusted. The conditioned sludge in the tank 3 is passed through a screen 4 to screen large-size particles such as gravel and the like, and is introduced into the mixing tank 5. Next, a predetermined amount of water 6 is mixed with the sludge in the tank 5 and mixed. Next, the mixed sludge in the tank 5 is introduced into the stirring tank 7, and a predetermined amount of the solidifying material 8 is added thereto, mixed and stirred to obtain a fluidized soil product. This product is transported to the destination by a transport vehicle 9 and used as a construction material for backfilling and the like.

The fluidized soil of another embodiment (Embodiment 2) of the present invention is replaced with water of Embodiment 1 and muddy water containing fine-grained soil such as clay in the conditioned sludge and solidified material Are mixed at a predetermined ratio. Specifically, instead of the water 6, a predetermined amount of muddy water 6A (muddy water containing fine-grained soil such as clay) is mixed and mixed with the adjusted sludge, and a predetermined amount of solidifying material is added thereto, mixed, and stirred. Get it. Other steps are the same as those in FIG. Fine-grained soil such as clay plays a role of a solidifying material and has an effect of reducing breathing.

As the mud, mud generated or discharged during construction work (construction mud) can be used. Construction mud has a general component amount of water: 70 to
95%, clay (0.005 mm or less): 5 to 30%, silt (0.074 to 0.005 mm range): 0 to 10
%, Sand (range of 2 to 0.074 mm): 0 to 5%, and gravel (2 mm or more): 0%. Thus, the construction mud contains considerable fine-grained soil such as clay. Therefore, by using the construction mud, it is possible to contribute to resource saving and mud recycling. Instead of the construction mud, it is also possible to add natural clay to the water to de-mud it and use it.

The mixing ratio of the muddy water and the solidified material with respect to the adjusted sludge can be set according to the application and the like as in the first embodiment. A range of about 3.5, and a range of about 0.4 to about 0.6 of the solidifying material with respect to the mixed composition 10 of the both. Thus, fluidized soil having the same effects as in the first embodiment can be manufactured. In addition,
According to the second embodiment, the amount of the solidifying material used can be reduced as compared with the first embodiment.

The fluidized soil according to another embodiment (Embodiment 3) of the present invention is an improved soil obtained by solidifying construction sludge,
Obtained by mixing water and solidifying material. The improved soil is produced by performing a treatment in accordance with the type of construction sludge, moisture content, and the like. Specifically, for example, a flocculant such as a polymer flocculant is added to the construction sludge to coagulate, and this is dried by solar drying or the like, or dehydrated and concentrated by a centrifugal dehydrator or the like, and a solidifying material is added. Solidified and cured as necessary. In this case, it is passed through a mud screen or the like in an optional step to remove oversized objects such as gravel as described above. In the production of the improved soil, for example, when using hard construction sludge having a low water content, the above-described steps of coagulation, drying, or dehydration are omitted, and the solidification material is directly added to the construction sludge and solidified. , And can be improved soil. The moisture content of the improved soil obtained as described above is, for example, about 45% to about 5%.
5%.

The fluidized soil according to the third embodiment is obtained by mixing a predetermined amount of water with the improved soil, mixing and adding a predetermined amount of solidifying material, and stirring the mixture. The mixing ratio of the water and the solidifying material to the improved soil can be set according to the use and the like. For example, water is in a range of about 4 to about 6 with respect to the improved soil 10, and the mixing of the improved soil and water For the composition 10, the solidifying material may be in a range of about 0.6 to about 0.8. Thereby, it has fluidity, has a required uniaxial compressive strength (for example, 1.0 kg / cm ^{2 to} 5.0 kg / cm ² ), has a breathing rate of 3% or less, and has a flow value of about 160 to 3
Fluidized soil of about 00 mm is produced.

Next, the method for producing the fluidized soil according to the third embodiment will be described more specifically with reference to FIG. FIG. 2 is a block diagram schematically showing another example of the manufacturing process of the fluidized soil. In the figure, 11 is a transport vehicle for collecting and transporting the construction sludge 1, 12 and 12 are receiving tanks for charging the sludge 1, 13 is an intermediate treatment section for intermediately treating the sludge 1, 14 is improved soil, 15 Denotes a mud screen, 16 denotes a mixing tank, 17 denotes water, 18 denotes a stirring tank, 19 denotes a solidifying material such as cement, and 20 denotes a transport vehicle for shipping.

As shown in FIG. 2, the construction sludge 1 collected by the transport vehicle 11 is put into the receiving tank 12 and stored. The sludge in the tank 12 is transferred to the intermediate treatment unit 13 and the treatment unit 1
In step 3, for example, coagulation is performed by adding a coagulant, and the coagulation agent is dried by solar drying or the like, or dehydrated by a dehydrator, solidified by adding a solidifying material, and cured and cured as necessary. The soil 14 is manufactured. Next, the improved soil 14 is passed through a screen 15 to screen oversize objects such as gravel, and is introduced into a mixing tank 16. Next, a predetermined amount of water 17 is added to and mixed with the improved soil 14 in the tank 16. Next, the prepared improved soil 14 in the tank 16 is introduced into a stirring tank 18, a predetermined amount of a solidifying material 19 is added thereto, mixed and stirred to obtain a fluidized soil product. This product is transported to the destination by the transport vehicle 20 and used as a construction material for backfilling.

In the above-mentioned process, in the production process of the improved soil 14, for example, when hard construction sludge having a low water content is used, as described above, the coagulation, drying, or dehydration in the intermediate treatment section 13 is performed. It is also possible to omit the processing steps such as the above, and to add the solidifying material directly to the construction sludge to perform solidification treatment to obtain the improved soil 14.

The fluidized soil of another embodiment (Embodiment 4) of the present invention is replaced with the water of Embodiment 3 and the improved soil is mixed with the muddy water and the solidified material at a predetermined ratio. Get it. Specifically, a predetermined amount of muddy water 17A containing fine-grained soil such as clay is mixed and mixed with the improved soil 14, and a predetermined amount of the solidifying material 19 is added, mixed, and stirred. Other steps are the same as those in FIG. Thus, a fluidized soil having the same function and effect as in the third embodiment can be manufactured. According to the fourth embodiment, the amount of the solidifying material used can be reduced as compared with the third embodiment.

[0026]

EXAMPLES Next, examples of the present invention will be described. It should be noted that the following embodiments are merely examples and do not limit the present invention.

In the embodiment described below, construction sludge collected at a construction foundation construction site in Nisshin-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture is collected, and muddy water containing fine-grained soil such as clay is collected in Ichikawa, Chiba Prefecture. The construction mud collected from the construction foundation construction site in Ono-cho was used. Further, groundwater was used as water and cement was used as a solidifying material. The cement is used by dissolving it in water, and the numerical values are shown in cement (solid content).

Example 1 165 Ltr of water and 85 kg of solidified material were mixed with 830 Ltr of adjusted sludge to obtain a fluidized soil.

(Example 2) 230 Ltr of muddy water and 80 kg of solidified material were mixed with 770 Ltr of adjusted sludge to obtain a fluidized soil.

(Example 3) With respect to 740 Ltr of improved soil,
260 Ltr of water and 85 kg of the solidified material were mixed to obtain a fluidized soil.

(Embodiment 4) With respect to 590 Ltr of improved soil,
410 Ltr of muddy water and 70 kg of solidified material were mixed to obtain a fluidized soil.

According to each of the above examples, fluidized soil having fluidity, a uniaxial compressive strength of about 1.5 kg / cm ² or more, a breathing rate of 3% or less, and a flow value of about 160 mm or more was obtained. . Each of these fluidized soils is suitable as a construction material for backfilling and the like.

[0033]

According to the present invention, construction sludge can be recycled as construction material for backfilling and the like, and the recycling rate can be improved. In addition, by recycling construction sludge, it is possible to reduce the amount of earth and sand used instead of earth and sand which is currently generally used as a material for backfilling. Therefore, it is possible to contribute to the prevention of environmental destruction caused by mining of forests and other soils (such as collecting sand).

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an example of a process for producing a fluidized soil according to the present invention.

FIG. 2 is a block diagram showing another example of the manufacturing process of the fluidized soil of the present invention.

[Explanation of symbols]

 1 Construction sludge 5 Mixing tank 6 Water 6A Muddy 7 Stirring tank

Claims (4)

[Claims] 1. A fluidized treated soil comprising a mixture of water and a solidifying material mixed with an adjusted sludge obtained by treating a construction sludge to adjust a water content to a predetermined ratio. 2. A sludge containing fine-grained soil, such as clay, is added to the adjusted sludge obtained by treating construction sludge and adjusting the water content to a predetermined ratio.
And a solidified material mixed with the fluidized soil. 3. A fluidized treated soil obtained by mixing water and a solidifying material with an improved soil obtained by solidifying construction sludge. 4. A fluidized soil comprising a mixture of improved soil obtained by solidifying construction sludge, muddy water containing fine-grained soil such as clay, and a solidifying material.