JPH0751799B2 - Excavator and sand reformer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for mechanically and electrically efficiently modifying excavated sediment having a high water content.

[Conventional technology and problems]

As is well known, a large amount of excavated earth and sand with a high water content is discharged by the shield construction method and underground continuous wall construction method that use a slurry or stabilizer. Such excavated soil with high water content is regulated as industrial waste and cannot be used as it is for landfilling. For this reason, various attempts have been made to modify the excavated soil,
The efficiency of the treatment process is being improved.

Conventional methods for modifying excavated soil are roughly classified into mechanical methods such as compression drying, and chemical methods that use solidifying materials. Mechanical methods are advantageous in that they can be reformed without the use of a solidifying material, but on the other hand, there is a limit to reforming, and dehydration cannot be sufficiently achieved only by compression. The chemical method can surely improve the solidification material to some extent, but it has a problem that the cost increases due to the increase of pH and the cost of the solidification material and the amount of sediment treatment.

[Object of the Invention]

The present invention is to solve the above-mentioned problem of excavated sediment modification, and more specifically, it can be easily installed at the site of shield construction, wall construction, etc., and the moisture content of the discharged sediment can be adjusted. ， In terms of cost to the extent that it is not treated as industrial waste,
It is intended to develop an apparatus that can effectively dehydrate and reform while satisfying functionality, continuous operability, and labor saving.

〔The invention's effect〕

The gist of the present invention which achieves the above-mentioned object is to mount a piston reciprocating in the axial direction in a cylindrical casing having a sediment inlet and a sediment outlet, and to install the piston in the casing. In a piston-type earth and sand conveying / compressing device which conveys and compresses earth and sand in the casing from the earth and sand inlet to the earth and sand outlet, a cathode and an anode for energizing the earth and sand in a compressed state in the casing It is characterized in that it is installed on the inner wall and provided with a water passage for dehydrating through the cathode.

That is, the present invention provides a piston type compression energizing device that significantly reduces the water content of excavated soil by using both mechanical compression and electroosmosis principle, and more specifically,
An opening on the one end side of the first casing communicates with an opening provided in the body of the second casing, and a cylindrical first casing with the axis in the horizontal direction and a cylindrical second casing with the axis in the vertical direction. The first piston for pushing out the earth and sand taken from the earth and sand intake into the casing toward the one end side opening is installed in the body of the first casing. A second piston is attached to push out the earth and sand taken into the second casing from the opening of the body of the casing toward the earth and sand discharge port on one end side of the second casing, and the inner wall at the earth and sand compression position in the first casing. An anode plate is arranged on the upper surface and a cathode plate is arranged on the lower surface, and a reforming device for excavated earth and sand is provided, in which the cathode plate is composed of a water-permeable material layer. In that case, the second piston has a wall surface sufficient to close the body opening of the second casing, and the second piston is used as a closing member for soil and sand compression in the first casing. It is advisable to provide a dehydration hole in the lower part at a position closer to the earth and sand intake than the cathode plate so that the earth and sand in the casing before entering the energization zone can be pre-dewatered. Further, it is preferable that the earth and sand intake is provided on the upper surface of the first casing, and a hopper having a stirring device is connected to the earth and sand intake so that the stirred earth and sand is charged into the first casing.

Examples of the drawings will be described below.

〔Example〕

FIG. 1 shows an apparatus according to the present invention for reforming excavated soil in a cylindrical first casing 1 having a square cross section with the axis as the horizontal direction. The first casing 1 itself is a tubular body having openings at both ends, and a first piston 2 that reciprocates in the first casing 1 is arranged. The excavated earth and sand taken into the casing is conveyed toward the discharge port of the one open end 4 by the extrusion of the first piston 2. A hopper 5 is installed at the sediment intake 3, and an agitator 6 is installed in the hopper 5. First piston 2
Is reciprocated by a first cylinder 7 connected to the other end of the first casing 1. The first piston 2 has a thickness sufficient to close the opening area of the earth and sand intake 3 with its wall surface 8, and the piston head surface 9 reciprocates across the opening of the earth and sand intake 3 to form a casing. The earth and sand taken in is conveyed toward the discharge port of the one open end 4.

One open end 4 of the first casing 1 communicates with the middle side of the second casing 10 whose axis is vertical. The second casing 10 is also a cylindrical body having a lower end opening having a rectangular cross section, and a second piston 11 which reciprocates therein is attached thereto. In the illustrated example, the second cylinder 12 is connected to the upper end of the second casing 10, and the second cylinder 12 causes the second piston 11 to reciprocate in the second casing 10. The second piston 11 is provided with an opening for connection with the first casing 1 provided in the middle portion of the second casing 10 (the opening area of which is one opening end 4 of the first casing 1).
Has a wall surface 13 large enough to cover an area (substantially equal to), and its piston head surface 14 has a stroke capable of reciprocating across the opening distance. The lower end opening 15 of the second casing 10 serves as an outlet for the modified soil.

If the piston pressing mechanism is connected in a two-step manner with such a relationship, the second piston 11 is now held at the position where it closes the opening end 4 of the first casing 1 and the first piston 2 is moved forward. (Move to the right in the drawing), the earth and sand are compressed in the first casing 1. Then, the second piston 11 is moved back (moved upward in the drawing) to release the blockage of the open end 4, and the first piston 2 is further moved to introduce the compressed earth and sand into the second casing 10. To be done.
The earth and sand introduced into the second casing 10 is the second piston 11
Is again moved to the position of the opening end 4 to be sequentially discharged toward the lower end opening 15. Therefore, if the excavated earth and sand are taken into the hopper 6 and the first piston 2 and the second piston 11 are driven in the above-mentioned relationship, they are sequentially discharged from the opening 15 of the second casing 10 through the compression process in the first casing 1. Will be.

In the device of the present invention, the energization (application) is performed during the earth and sand compression process in the first casing 1. For this purpose, the anode plate 17 is arranged on the upper surface of the first casing 1 near the open end 4, and the cathode plate 18 is arranged on the lower surface facing the anode plate 17. That is, the compression of earth and sand in the first casing 1 is
If the earth and sand transport distance in the casing is sufficient, the degree of consolidation increases from the earth and sand inlet 3 toward the opening end 4, and the highest consolidation is obtained near the opening end 4. A compression applying zone for applying a DC current between both electrodes is provided with the cathode facing down with respect to the earth and sand in this highly compacted state, and a water passage 19 for discharging water to the outside of the casing through this cathode plate 18.
To provide. Further, a water permeation hole 20 is also provided on the lower surface of the casing in the preliminary consolidation zone on the upstream side of the conveying flow (on the side of the sediment intake 3) with respect to the cathode plate 18.

FIG. 2 shows a casing cross section in the compression application zone. As shown in the figure, the insulating material 21 is attached to the upper surface of the first casing 1 to attach the anode plate 17, and the insulating material 22 is also attached to the lower surface.
A cathode plate (18) is attached via the water passage and a water passage (19) for discharging water to the outside of the casing through the cathode plate (18) and the insulating material (22) is provided. In practice, this water passage 19 is preferably constructed by using a water-permeable cathode (for example, a conductive mesh or a porous plate) and a water-permeable heat insulating material (for example, a porous resin or material).

According to the device of the present invention thus configured, the earth and sand compressed by the first piston 2 is pre-dewatered in the pre-consolidation zone in the first casing 1, and further compressed and de-watered in the application zone. Due to the electroosmotic principle, water that cannot be dehydrated by this compression alone is dehydrated. The water discharged in the pre-consolidation zone and the compression application zone is received by the lower dehydration receiver 23 by natural fall and collected.
On the other hand, the modified earth and sand that has been dehydrated into a cake shape is discharged from the lower end opening 15 of the second casing 10 by driving the first piston 2 and the second piston 11 described above.

According to the experiments conducted by the present inventors, when the sand + silt water content of 25% was pressed, the water content was 17% only by compression. However, under the same compression condition, the voltage was 100v and the current density was 0.3. ~
When a voltage of 0.5 A / dcm ² was applied for 6 to 12 minutes (layer thickness: 100 mm), a dehydrated cake having a water content reduced to 7 to 8% was obtained. Experiments were also performed when the voltage was increased to 200v, but there was no great difference from the case when the voltage was 100v. In addition, the latter had a dehydrating effect more than double when applied without applying pressure and when applied with applying pressure. Further, when the conductive powder (iron powder) was mixed in the earth and sand and compressed, the dehydration effect was further improved.

〔The invention's effect〕

According to the device of the present invention, it is possible to dehydrate the excavated soil exceeding the limit of mechanical dehydration (pressure dehydration), and it is possible to reuse the excavated soil having a high water content generated by the shield construction method or the wall construction method. Further, since the device of the present invention has a simple structure and is compact, it can be installed at a construction site and can be modified by a source of excavated earth and sand. In particular, the apparatus of the present invention can perform continuous (batch type) processing, so that the apparatus of the present invention can be incorporated in the process of transporting excavated soil and the work can be rationalized.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the device of the present invention, and FIG. 2 is a schematic sectional view taken along the line II-II 'of FIG. 1 …… First casing, 2 …… First piston, 3 …… Sediment inlet, 4 …… Opening end of the first casing (sediment outlet), 5…
… Hopper, 6 …… stirring blade, 7 …… first cylinder, 10 ……
Second casing, 11 …… Second piston, 12 …… Second cylinder, 15 …… Soil discharge port, 17 …… Anode, 18 …… Cathode, 19 ……
Waterway, 23 …… Received dehydration.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-1426 (JP, A) JP 61-18410 (JP, A) JP 59-2727 (JP, U)

Claims (5)

[Claims] 1. A piston that reciprocates in the axial direction is mounted in a cylindrical casing having a sediment intake port and a sediment discharge port,
In a piston-type earth and sand conveying / compressing device which conveys and compresses earth and sand in the casing from the earth and sand inlet provided in the casing to the earth and sand discharge port by this piston, with respect to the earth and sand in a compressed state in the casing An excavating earth and sand reforming device, characterized in that an energizing cathode and an anode are installed on an inner wall of a casing, and a water passage for dehydrating through the cathode is provided. 2. A cylindrical first casing having a horizontal axis, and a second cylindrical casing having a vertical axis are provided at one end of the first casing in an opening provided in a body portion of the second casing. The first piston for connecting the openings on the side so that they communicate with each other, providing a sediment inlet on the body of the first casing, and for pushing the sediment taken into the casing from the inlet toward the opening on the one end side. Install a second piston to push out the earth and sand taken into the second casing from the opening of the body of the second casing toward the earth and sand discharge port on the one end side of the second casing. A device for modifying excavated sediment, in which an anode plate is arranged on the upper surface of the inner wall and a cathode plate is arranged on the lower surface at the sand compression position, and the cathode plate is composed of a water-permeable material layer. 3. The excavated soil reforming apparatus according to claim 2, wherein the second piston has a wall surface sufficient to close the opening of the body of the second casing. 4. The excavating earth and sand reforming device according to claim 2, wherein a dehydration hole is also provided in the lower portion of the first casing on the earth and sand intake side of the cathode plate. 5. The reforming of excavated sediment according to claim 2, 3 or 4, wherein the sediment intake is provided on the upper surface of the first casing, and a hopper with a stirring device is connected to the sediment intake. apparatus.