JP2018119348A - Improvement device of weak ground and improvement method of weak ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improvement device of a weak ground and an improvement method of a weak ground which prevent air in the outside of an airtight sheet from flowing in a drain passage to reduce a differential pressure between a negative pressure in the inside of the airtight sheet and an atmospheric pressure, and thereby improve a water absorption effect from each drain material and can improve an effect of ground improvement.SOLUTION: An improvement device includes: a plurality of members 5 for vertical drainage arranged in a vertical direction inside of a ground 3 as an improvement object; a plurality of members 7 for horizontal drainage which are arranged on a surface 3a of the ground in a horizontal direction and are connected to the members 5 for vertical drainage so as to delivery and receive water; an airtight sheet 11 which is laid so as to cover the surface 3a of the ground together with the members 7 for horizontal drainage and where a peripheral edge portion 11a is embedded along the peripheral edge portion of the ground 3 in the ground 3 to a predetermined depth; a vacuum pump 21 for drain connected to the members 7 for horizontal drainage; a member 17 for air suction arranged along the peripheral edge portion 11a of the airtight sheet 11; and a vacuum pump 25 for air suction connected to the members 17 for air suction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a soft ground improving device and a soft ground improving method for removing water from a soft ground containing a lot of water to improve the soft ground into a hard ground.

  The conventional soft ground improvement method is to cover the surface of the ground to be improved with an air-tight sheet, vent the air inside the air-tight sheet with a vacuum pump, and generate negative pressure on the ground to be improved. A method of making water infiltrate inside the drain material provided in the soil or on the soil and discharging the water to the outside of the ground through the inside of the drain material has been known (for example, FIG. 4).

  6 to 9 are diagrams for reference in order to describe a conventional soft ground improvement device used in a conventional soft ground improvement method.

  As shown in FIG. 6, the conventional apparatus for improving soft ground is such that a large number of vertical drain members 5 extend in the vertical direction at predetermined intervals in the horizontal direction within the ground 3 to be improved. The upper end portion 5a of the vertical drain material 5 protrudes upward from the ground surface 3a.

  As shown in FIGS. 6 and 7, a plurality of horizontal drain members 7 are arranged on the ground surface 3a so as to extend in the horizontal direction, and are arranged parallel to each other at a predetermined interval. And the upper end part 5a of the vertical drain material 5 was arrange | positioned in the several position of the length direction of the horizontal drain material 7 so that water may be delivered.

  As shown in FIG. 8, the vertical drain member 5 and the horizontal drain member 7 are formed in an elongated rectangular shape in a cross section perpendicular to the length direction, and the cross section includes the center plate portion 61 and both front and back surfaces thereof. And a membrane member 65 covering the periphery of the core member.

  And the space | gap 67 is formed between the center board part 61 and the standing part 63 of the core member of the cross section shown in FIG. 8, and the filter 65, and this space | gap 67 is the length direction of the drain materials 5 and 7. FIG. It is continuous. Then, water enters the gap 67 inside the drain material through the eyes of the filter 65, and the invaded water can move in the length direction of the drain materials 5 and 7 through the gap 67.

  Next, as shown in FIGS. 6 and 7, the water collecting pipe 9 is disposed on the ground surface 3 a so as to extend in the horizontal direction, and is disposed so as to be orthogonal to the plurality of horizontal drain members 7. As shown in FIG. 9, the water collecting pipe 9 has a tubular member 9b in which a plurality of through-holes 9a whose axis is directed to the center of the pipe are formed in the circumferential thick part, and the periphery of the tubular member 9b. And a film-like filter 9c covering the surface.

  As shown in FIG. 6, the water collecting pipe 9 and the horizontal drain material 7 are arranged so that the convex curved surface and the concave curved surface are in contact with each other, and the gap 67 of the horizontal drain material 7 as shown in FIG. 65, the eyes of the filter 9c of the water collecting pipe 9 as shown in FIG. 9, and the through-hole 9a were in communication with each other so that water could be delivered.

  And, as shown in FIG. 6, from above the horizontal drain material 7, the water collecting pipe 9 and the ground surface 3a of the ground 3 to be improved exposed between them, so as to cover the entire surface of the ground surface 3a, An airtight sheet 11 was laid.

  As shown in FIG. 7, the airtight treatment of the peripheral portion 11 a of the airtight sheet 11 is performed by forming the sheet embedding hole 13 having a V-shaped cross section so as to surround the ground 3 along the peripheral portion of the ground 3 to be improved. The excavation was performed by embedding the peripheral edge portion 11a of the airtight sheet 11 therein.

  And as shown in FIG. 6, the edge part by the side of the ground 3 of the drainage pipe 19 penetrates the airtight sheet | seat 11, and is connected to the water collecting pipe 9, and the edge part of the drainage pipe 19 on the opposite side to the ground 3 is a negative pressure. It was connected to the vacuum pump 21 for drain which is the generation source. The drain pipe 19 is a non-porous tubular member in which a through-hole is not formed in the circumferential thick part, and its end is connected to the water collecting pipe 9 in consideration of the air-tightness of the air-tight sheet 11. It had been.

  According to the conventional soft ground improvement method using such a conventional soft ground improvement device, the drain vacuum pump 21 is operated to operate the air inside the water collection pipe 9 or the through hole 9a of the water collection pipe 9. By passing the air between the airtight sheet 11 and the ground surface 3a through the air, negative pressure is generated in the ground 3 to be improved, and thereby the ground 3 is transmitted along the vertical drain material 5 and the horizontal drain material 7. The water inside is sucked into the water collecting pipe 9 and discharged to the outside of the ground 3. As a result, the soft ground containing a lot of moisture can be improved and changed to the intended hard ground.

Japanese Patent No. 3138909

  However, in the conventional soft ground improvement method as described above, when the drain vacuum pump 21 is operated, the moisture inside the ground 3 is caused by the negative pressure generated between the airtight sheet 11 and the ground surface 3a. At the same time as being discharged to the outside, air outside the airtight sheet 11 was sucked into the airtight sheet 11 from the ground 3 around the peripheral edge portion 11 a of the airtight sheet 11 embedded in the sheet embedding hole 13.

  The air sucked into the inside of the airtight sheet 11 drains moisture originally from the ground 3 such as the vertical drain material 5 to the horizontal drain material 7, the water collection pipe 9, the drain pipe 19, and the drain vacuum pump 21. It was discharged along with the water inside the ground 3 through a route for the purpose (hereinafter referred to as “drainage route”).

  And the air suck | inhaled from the outside of the airtight sheet | seat 11 flows into a waste_water | drain path | route, The differential pressure | voltage between the negative pressure which generate | occur | produces in the ground 3 to be improved, and atmospheric pressure becomes small, and from each drain material There was a problem that the water absorption effect, and thus the improvement effect of the soft ground, would be reduced.

  In such a situation, in order to increase the differential pressure between the negative pressure generated in the ground 3 and the atmospheric pressure, it is necessary to replace the drain vacuum pump 21 with one having a large exhaust capacity. Further, there is a problem that the cost for the drain vacuum pump 21 and the cost for the soft ground improvement device are increased.

  In addition, since air sucked from the outside of the airtight sheet 11 and water sucked from the inside of the ground 3 flow together in the drainage path, in order to secure a necessary flow rate of water, disconnection of drain material and piping is required. There is a need to replace it with one having a large area. As a result, there is a problem that the cost for the drain material and the piping increases, and the cost for the improvement device for the soft ground increases.

  Therefore, in view of the above problems, the present invention prevents the air outside the airtight sheet from flowing into the drainage path and reducing the differential pressure between the negative pressure inside the airtight sheet and the atmospheric pressure. It is an object of the present invention to provide a soft ground improvement device and a soft ground improvement method capable of improving the water absorption effect from each drain material and improving the ground improvement effect.

In order to solve the above problems, the improvement device for soft ground according to the present invention is:
A plurality of vertical drainage members arranged vertically in the ground to be improved;
A plurality of horizontal drainage members arranged in a horizontal direction on the surface of the ground, and connected so as to be able to deliver water to the vertical drainage members;
An airtight sheet laid so as to cover the surface of the horizontal drainage member and the ground, and a peripheral portion embedded in a predetermined depth of the ground along the peripheral portion of the ground;
A drain vacuum pump connected to the horizontal drainage member;
An air intake member disposed along a peripheral edge of the airtight sheet;
An intake vacuum pump coupled to the intake member;
Actuate the drain vacuum pump, drain the water in the ground through the vertical drainage member and the horizontal drainage member,
The suction vacuum pump is operated so that air entering between the airtight sheet and the ground is discharged from the peripheral portion of the ground through the suction member.

Moreover, the soft ground improving device according to the present invention is:
The intake member is embedded in a predetermined depth of the ground along the peripheral edge of the ground together with the peripheral edge of the airtight sheet.

Moreover, the soft ground improving device according to the present invention is:
The intake member is disposed on a peripheral portion of the surface of the ground,
A vertical intake member is arranged in the vertical direction inside the ground at intervals along the peripheral edge of the ground,
The vertical intake member and the intake member are arranged to be connected so that air can be delivered,
The airtight sheet is laid so as to cover the surface of the horizontal drainage member, the intake member and the ground.

In order to solve the above problems, the improvement method of the soft ground according to the present invention is:
Moisture in the ground is sucked by a plurality of vertical drainage members arranged in the vertical direction inside the ground to be improved,
It is arranged horizontally on the surface of the ground, and absorbs moisture in the ground by a plurality of horizontal drainage members connected so as to be able to transfer water with the vertical drainage member,
Laying so as to cover the horizontal drainage member and the surface of the ground, and sealing the ground surface with an airtight sheet in which the peripheral edge is embedded at a predetermined depth of the ground along the peripheral edge of the ground,
Inhale from the air intake member arranged along the peripheral edge of the airtight sheet and discharge it to the outside of the ground,
Actuate a drain vacuum pump connected to the horizontal drainage member, absorb water from the vertical drainage member and the horizontal drainage member, and discharge it to the outside of the ground.
The suction vacuum pump connected to the suction member is operated, and the suction member sucks air that enters between the airtight sheet and the ground from the peripheral edge of the ground and discharges it to the outside of the ground. It is characterized by the fact that the

Moreover, the improvement method of the soft ground according to the present invention is:
The intake member is embedded in a predetermined depth of the ground along the peripheral edge of the ground together with the peripheral edge of the airtight sheet.

Moreover, the improvement method of the soft ground according to the present invention is:
The intake member is disposed on a peripheral portion of the surface of the ground,
A vertical intake member is arranged in the vertical direction inside the ground at intervals along the peripheral edge of the ground,
The vertical intake member and the intake member are arranged to be connected so that air can be delivered,
The airtight sheet is laid so as to cover the surface of the horizontal drainage member, the intake member and the ground.

According to such a soft ground improving device according to the present invention,
A plurality of vertical drainage members arranged vertically in the ground to be improved;
A plurality of horizontal drainage members arranged in a horizontal direction on the surface of the ground, and connected so as to be able to deliver water to the vertical drainage members;
An airtight sheet laid so as to cover the surface of the horizontal drainage member and the ground, and a peripheral portion embedded in a predetermined depth of the ground along the peripheral portion of the ground;
A drain vacuum pump connected to the horizontal drainage member;
An air intake member disposed along a peripheral edge of the airtight sheet;
An intake vacuum pump coupled to the intake member;
Actuate the drain vacuum pump, drain the water in the ground through the vertical drainage member and the horizontal drainage member,
By operating the vacuum pump for intake, and letting out the air entering between the airtight sheet and the ground from the peripheral portion of the ground through the member for intake,
By preventing the air outside the airtight sheet from flowing into the drainage path and reducing the differential pressure between the negative pressure and the atmospheric pressure inside the airtight sheet, the water absorption effect from each drain material is improved and the ground The effect of the improvement can be improved.

Moreover, according to the improved construction method of the soft ground according to the present invention,
Moisture in the ground is sucked by a plurality of vertical drainage members arranged in the vertical direction inside the ground to be improved,
It is arranged horizontally on the surface of the ground, and absorbs moisture in the ground by a plurality of horizontal drainage members connected so as to be able to transfer water with the vertical drainage member,
Laying so as to cover the horizontal drainage member and the surface of the ground, and sealing the ground surface with an airtight sheet in which the peripheral edge is embedded at a predetermined depth of the ground along the peripheral edge of the ground,
Inhale from the air intake member arranged along the peripheral edge of the airtight sheet and discharge it to the outside of the ground,
Actuate a drain vacuum pump connected to the horizontal drainage member, absorb water from the vertical drainage member and the horizontal drainage member, and discharge it to the outside of the ground.
The suction vacuum pump connected to the suction member is operated, and the suction member sucks air that enters between the airtight sheet and the ground from the peripheral edge of the ground and discharges it to the outside of the ground. By doing so,
By preventing the air outside the airtight sheet from flowing into the drainage path and reducing the differential pressure between the negative pressure and the atmospheric pressure inside the airtight sheet, the water absorption effect from each drain material is improved and the ground The effect of the improvement can be improved.

It is the vertical sectional view showing the outline of the improvement device of the soft ground concerning the 1st embodiment of the present invention. It is a top view of the soft ground improvement apparatus shown in FIG. 2 is a perspective view showing the structure of an intake pipe 17. FIG. It is the vertical sectional view which showed the outline of the improvement apparatus of the soft ground which concerns on the 2nd Embodiment of this invention. It is a top view of the soft ground improvement apparatus shown in FIG. It is the vertical sectional view which showed the outline of the conventional soft ground improvement apparatus. It is a top view of the improvement apparatus of the conventional soft ground shown in FIG. It is sectional drawing which shows the structure of a drain material. 3 is a perspective view showing the structure of a water collecting pipe 9. FIG.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the soft ground improvement apparatus and soft ground improvement method by this invention is demonstrated concretely based on drawing.

  1 to 3 are diagrams which are referred to for describing the soft ground improving apparatus according to the first embodiment of the present invention. In addition, the same code | symbol shall be attached | subjected and demonstrated to the part similar to the conventional soft ground improvement apparatus shown in FIG. 6 thru | or FIG.

  As shown in FIG. 1, the soft ground improving device according to the first embodiment of the present invention includes a large number of vertical drain members 5 (vertical drainage members) in the horizontal direction inside the ground 3 to be improved. Are placed in the ground so as to extend in parallel to each other at a predetermined interval, and the upper end portion 5a of the vertical drain material 5 projects upward from the ground surface 3a.

  Further, as shown in FIG. 2, a plurality of horizontal drain members 7 (horizontal drainage members) are arranged on the ground surface 3a so as to extend in the horizontal direction, and are arranged in parallel with each other at a predetermined interval. . And the upper end part 5a of the vertical drain material 5 is connected to the several position of the length direction of the horizontal drain material 7 so that water may be delivered.

  Such a connection between the horizontal drain material 7 and the vertical drain material 5 is achieved by, for example, bending the upper end portion 5a of the vertical drain material 5 protruding from the ground surface 3a and overlapping the horizontal drain material 7, and stapling the two overlapped members. It is done by work such as fixing with a large stapler.

  The vertical drain material 5 and the horizontal drain material 7 are formed in an elongated rectangular shape in a cross section perpendicular to their length direction, similar to the conventional one shown in FIG. And a core member having a plurality of standing portions 63 formed on both front and back surfaces thereof, and a membrane filter 65 covering the periphery of the core member.

  A gap 67 is formed between the center plate portion 61 and the standing portion 63 of the core member and the filter 65 in the drain cross section shown in FIG. 8, and this gap 67 is the length direction of the drain members 5 and 7. It is continuous. Then, when water enters the gap 67 inside the drain material through the eyes of the filter 65, the entered water can move in the length direction of the drain materials 5 and 7 through the gap 67.

  The vertical drain material 5 and the horizontal drain material 7 are, for example, a plastic board made of hard vinyl chloride or polyolefin resin, in which a core member having a center plate portion 61 and an upright portion 63 is covered with a polyester non-woven filter 65. A drain can be used, or a drain material using a biodegradable resin material can be used in consideration of reducing environmental burden.

  Next, as shown in FIGS. 1 and 2, the water collecting pipe 9 is disposed on the ground surface 3 a so as to extend in the horizontal direction, and is disposed so as to be orthogonal to the plurality of horizontal drain members 7. As shown in FIG. 9, the water collecting pipe 9 has a tubular member 9b in which a plurality of through-holes 9a whose axis is directed to the center of the pipe are formed in the circumferential thick part, and the periphery of the tubular member 9b. Is provided with a film-like filter 9c covering the surface.

  In addition, an end of the drainage pipe 19 using, for example, a hard polyvinyl chloride pipe is connected to the water collecting pipe 9 on the ground surface 3a side. In order to maintain the airtightness of the airtight sheet 11, for example, a part of the airtight sheet 11 is opened and the drainage pipe 19 is inserted into the opening and connected to the water collecting pipe 9. The airtight sheet 11 is bound from the outside of the airtight sheet 11 so as to close a gap between the opening of the airtight sheet 11 and the surrounding airtight sheet 11 (a tightening tool used to tighten the end of the gas pipe hose to the gas pipe) ) By tightening it to the drain pipe 19.

  A drain vacuum pump 21 is connected to the other end of the drain pipe 19.

  As shown in FIG. 1, the water collection pipe 9 and the horizontal drain material 7 are arranged so that the convex curved surface and the concave curved surface are in contact with each other, and the gap 67 of the horizontal drain material 7 as shown in FIG. 65, the eyes of the filter 9c of the water collecting pipe 9 as shown in FIG. 9, and the through-hole 9a communicate with each other so that water can be delivered. As the water collection tube 9, for example, a tubular member 9b made of hard vinyl chloride and a non-woven membrane filter 9c can be used.

  And as shown in FIG. 1, the airtight sheet | seat 11 is covered so that the whole surface of the ground surface 3a may be covered on the horizontal drain material 7, the water collection pipe | tube 9, and the ground surface 3a of the ground 3 of improvement object exposed from them. Is laid. For example, a sheet made of a synthetic resin such as soft vinyl chloride can be used as the air insurance tight sheet 11.

  When the ground 3 has a large area, a single large airtight sheet 11 may be formed by arranging a plurality of ready-made sheets having a predetermined width and adhering adjacent end portions thereof. Moreover, since the airtightness will be impaired if the airtight sheet 11 is damaged, a protective mat may be laid over the airtight sheet 11.

  Next, as shown in FIG. 2, a sheet-embedded hole 13 having a V-shaped cross section is dug so as to surround the ground 3 along the peripheral edge of the ground 3 to be improved, and an air-tight sheet is formed therein. The peripheral edge 11a of 11 is hung and arrange | positioned.

  Next, as shown in FIGS. 1 and 2, along the shape of the peripheral portion 11 a of the airtight sheet 11, the intake pipe 17 (intake member) is connected to the peripheral portion of the airtight sheet 11 at the bottom of the sheet embedding hole 13. 11a is disposed below.

  As shown in FIG. 3, the intake pipe 17 includes a tubular member 17b in which a plurality of through-holes 17a whose axis is directed to the center of the pipe are formed in the circumferential thick part, and the periphery of the tubular member 17b. Is provided with a film-like filter 17c.

  That is, the intake pipe 17 can suck air outside the pipe into the pipe through the through-hole 17a. However, the intake pipe 17 includes a filter 17c that covers the periphery of the tubular member 17b. It is configured to prevent intrusion.

  Next, as shown in FIGS. 1 and 2, one end of the exhaust pipe 23 is connected to the intake pipe 17 disposed in the seat embedding hole 13, and the other end of the exhaust pipe 23 is connected to the intake vacuum pump 25. Are connected and provided. The exhaust pipe 23 is a non-porous tubular member in which a plurality of through holes are not formed in the circumferential thick portion, and for example, a hard polyvinyl chloride pipe can be used as the exhaust pipe 23.

  Then, by refilling the sheet embedding hole 13 with the backfilling soil 15, the airtight treatment of the peripheral edge portion 11 a of the airtight sheet 11 can be performed.

  An embodiment of the soft ground improvement method implemented using such a soft ground improvement device will be described below.

  By operating the drain vacuum pump 21, the airtight sheet 11 and the ground surface 3a pass through the air inside the water collecting pipe 9 and the through-hole 9a of the water collecting pipe 9 in the same manner as the conventional soft ground improvement method. The air in between is sucked, and negative pressure is generated in the ground 3 to be improved, whereby moisture in the ground 3 is sucked into the water collecting pipe 9 through the vertical drain 5 material and the horizontal drain material 7, and the ground 3 It is discharged outside.

  At the same time, by operating the suction vacuum pump 25, the air around the peripheral portion 11 a of the airtight sheet 11 embedded in the sheet embedding hole 13 is sucked into the intake pipe 17 and passes through the exhaust pipe 23. Discharged.

  In the conventional soft ground improvement method, the air outside the airtight sheet 11 is sucked into the airtight sheet 11, so that the pressure between the negative pressure acting on the ground 3 inside the airtight sheet 11 and the atmospheric pressure is reduced. Whereas the differential pressure has been reduced, according to the soft ground improvement method according to this embodiment, the air outside the airtight sheet 11 is exhausted through the path of the intake pipe 17 and the exhaust pipe 23, and is vertically Since the water inside the ground 3 is discharged through the drain 5 material and the horizontal drain material 7 through a different route from the drainage route in which the water is sucked into the water collecting pipe 9, the air outside the airtight sheet 11 is discharged into the drainage. The amount flowing into the path can be reduced.

  And by this, the differential pressure | voltage between the atmospheric pressure of the negative pressure which acts on the ground 3 inside the airtight sheet | seat 11 when the air outside the airtight sheet | seat 11 flows into the said drainage path like the past reduces. Since a negative pressure having a large difference from the atmospheric pressure can be generated, the water absorption effect from each drain material, and thus the ground improvement effect can be improved.

  Further, since a negative pressure with a large difference from the atmospheric pressure can be obtained without increasing the exhaust capacity of the drain vacuum pump 21, it is possible to prevent an increase in cost caused by increasing the exhaust capacity of the drain vacuum pump 21. As a result, it is possible to prevent an increase in the cost of the soft ground improvement device.

  In addition, since the flow rate of water and air in the drainage path is reduced, there is no need to increase the cross-sectional area of the drain material and piping, so that it is possible to prevent high costs, and consequently the improvement device for soft ground. High cost can be prevented. Moreover, the workability of the drain material and the piping is improved, and the construction period can be shortened.

  Further, since the intake pipe 17 is disposed below the peripheral edge portion 11 a of the airtight sheet 11, only the air reaching the lower side of the airtight sheet 11 is sucked into the intake pipe 17, and the air above the airtight sheet 11 is taken up. Since there is no suction, it is possible to efficiently inhale only the air at a place where there is a high possibility of flowing into the drainage path.

  As described above, according to the first embodiment of the present invention, it is possible to prevent the air outside the airtight sheet from flowing into the drainage path and reducing the differential pressure between the negative pressure inside the airtight sheet and the atmospheric pressure. By doing, the water absorption effect from each drain material can be improved, and the effect of ground improvement can be improved.

  4 and 5 are diagrams which are referred to for explaining a soft ground improving device according to a second embodiment of the present invention. In addition, the same code | symbol shall be attached | subjected and demonstrated to the part similar to the soft ground improvement apparatus which concerns on the said 1st Embodiment.

  As shown in FIG. 4, the soft ground improving device according to the present embodiment has an intake pipe 17 disposed on the ground surface 3 a on the inner side of the airtight sheet 11, and for intake air placed on the periphery of the ground 3. It is different from the soft ground improving apparatus in the first embodiment in that it is connected to the vertical drain member 18 (vertical intake member).

  That is, a plurality of intake vertical drain materials 18 are placed along the peripheral edge of the ground 3 at a predetermined interval in the horizontal direction. The intake vertical drain member 18 is a member having a structure similar to that shown in FIG. The intake vertical drain members 18 are placed in the ground 3 in parallel to each other in the vertical direction, and the upper end portions protrude upward from the ground surface 3a.

  Next, as shown in FIG. 5, the intake pipe 17 (intake member) is disposed on the peripheral portion of the ground surface 3a so as to extend in the horizontal direction. The intake pipe 17 is a member having a structure similar to that shown in FIG. Further, the upper ends of the intake vertical drain members 18 projecting upward from the intake pipe 17 and the ground surface 3a are in contact with each other, and are connected so that water and air can be passed between them.

  Then, an airtight sheet 11 is formed on the horizontal drain material 7, the water collection pipe 9, the intake pipe 17, and the ground surface 3 a of the ground 3 to be improved exposed between them so as to cover the entire surface of the ground surface 3 a. Lay down. The peripheral portion 11a of the airtight sheet 11 is subjected to an airtight treatment, and this airtight treatment is performed by embedding it in a sheet embedding hole 13 excavated on the outer edge of the ground 3 to be improved, in the same manner as a conventional soft ground improvement device.

  One end of the exhaust pipe 23 penetrates the airtight sheet 11 and is connected to the intake pipe 17, and the other end of the exhaust pipe 23 is connected to the intake vacuum pump 25. The exhaust pipe 23 is a non-porous tubular member in which a through hole is not formed in the circumferential thick portion, and is connected to the intake pipe 17 so as not to impair the airtightness of the airtight sheet 11.

  Other configurations are the same as those of the soft ground improving apparatus according to the first embodiment. That is, the vertical drain material 5 is placed inside the ground 3, the horizontal drain material 7 and the water collecting pipe 9 are disposed on the ground surface 3 a, and the drain pipe 19 and the drain vacuum pump 21 are connected to the water collecting pipe 9. ing.

  Also by the soft ground improvement method using the soft ground improvement device according to such an embodiment, the air outside the airtight sheet 11 passes through the path of the intake vertical drain material 18, the intake pipe 17, and the exhaust pipe 23. It is discharged through the vertical drain 5 material and the horizontal drain material 7, and is discharged through a different route from the drainage route in which the water inside the ground 3 is sucked into the water collection pipe 9. The amount of external air flowing into the drainage path can be reduced.

  And by this, the differential pressure | voltage between the atmospheric pressure of the negative pressure which acts on the ground 3 inside the airtight sheet | seat 11 when the air outside the airtight sheet | seat 11 flows into the said drainage path like the past reduces. Therefore, it is possible to generate a negative pressure having a large differential pressure with respect to the atmospheric pressure, so that it is possible to improve the water absorption effect from each drain material, and thus the ground improvement effect.

  Further, since a negative pressure with a large difference from the atmospheric pressure can be obtained without increasing the exhaust capacity of the drain vacuum pump 21, it is possible to prevent an increase in cost caused by increasing the exhaust capacity of the drain vacuum pump 21. As a result, it is possible to prevent an increase in the cost of the soft ground improvement device.

  In addition, since the flow rate of water and air in the drainage path is reduced, there is no need to increase the cross-sectional area of the drain material and piping, so that it is possible to prevent high costs, and consequently the improvement device for soft ground. High cost can be prevented. Moreover, the workability of the drain material and the piping is improved, and the construction period can be shortened.

  Further, since the installation of the vertical drain material 18 for intake air is substantially the same as the installation of the vertical drain material 5, it can be applied continuously, and the arrangement of the intake pipe 17 and the arrangement of the water collecting pipe 9 are also the same. Since it is almost the same, it can be constructed continuously. For this reason, the construction content is simple and the construction period can be further shortened compared to the first embodiment that requires a new step of embedding the intake pipe 17 in the seat embedding hole 13.

  Such a second embodiment of the present invention also prevents the air outside the airtight sheet from flowing into the drainage path and reducing the differential pressure between the negative pressure inside the airtight sheet and the atmospheric pressure. Thereby, the water absorption effect from each drain material can be improved, and the effect of ground improvement can be improved.

  The present invention is not limited to the first and second embodiments, and various modifications are possible as long as the object of the present invention can be achieved.

  For example, in the soft ground improvement apparatus according to the first and second embodiments, the water is discharged from the inside of the ground 3 by the single drain vacuum pump 21, but the present invention is not limited thereto. There is no need, and a plurality of drain vacuum pumps 21 may be used.

  Further, when the ground 3 to be improved has a large area, the ground 3 is divided into a plurality of blocks, and a drainage path is provided for each block, and a drain vacuum pump 21 is provided for each drainage path. Good.

Similarly, in the soft ground improvement device according to the first and second embodiments, the entire intake pipe 17 arranged around the ground 3 is sucked by a single suction vacuum 25 pump. However, the present invention is not limited to these, and a plurality of intake vacuum pumps 25 may be used.
For example, the intake pipe 17 disposed on the outer periphery of the ground 3 may be divided into a plurality of sections, and the intake vacuum pump 25 may be installed for each section.

  Moreover, you may use together the improvement apparatus of the soft ground which concerns on the said 1st, 2nd embodiment. That is, in addition to a path for intake air from the intake pipe 17 embedded in the seat embedding hole 13, a path for intake air from the intake pipe 17 connected to this by placing the vertical drain material 18 for intake air on the peripheral edge of the ground 3. By providing the air through the two paths, the amount of air outside the airtight sheet 11 flowing into the drainage path may be further reduced, and the ground improvement effect may be further improved.

  Moreover, in the soft ground improvement apparatus according to the first and second embodiments, the drain material as shown in FIG. 8 is used as the vertical drainage member and the horizontal drainage member. It is not necessary to be limited to drain material, for example, for drainage of other structures such as sand piles (sand piles) and sand layers (sand mats) formed using gravel or the like that can penetrate water and air inside A member may be used.

  Moreover, in the soft ground improvement device according to the first and second embodiments, the airtight sheet 11 is pressed onto the ground surface 3a of the ground 3 by atmospheric pressure due to the negative pressure generated on the ground 3, The ground improvement may be further promoted by performing a loading embankment on the airtight sheet 11 and using it together with pressing by the loading.

DESCRIPTION OF SYMBOLS 3 Ground 3a Ground surface 5 Vertical drain material 5a Upper end part 7 Horizontal drain material 9 Water collecting pipe 9a Through-hole 9b Tubular member 9c Filter 11 Airtight sheet 11a Peripheral part 13 Sheet embedding hole 15 Backfill soil 17 Intake pipe 17a Through-hole 17b Tubular member 17c Filter 18 Vertical drain material for intake 19 Drain pipe 21 Vacuum pump for drain 23 Exhaust pipe 25 Vacuum pump for intake 61 Center plate part 63 Standing part 65 Filter 67 Air gap

Claims (6)

A plurality of vertical drainage members arranged vertically in the ground to be improved;
A plurality of horizontal drainage members arranged in a horizontal direction on the surface of the ground, and connected so as to be able to deliver water to the vertical drainage members;
An airtight sheet laid so as to cover the surface of the horizontal drainage member and the ground, and a peripheral portion embedded in a predetermined depth of the ground along the peripheral portion of the ground;
A drain vacuum pump connected to the horizontal drainage member;
An air intake member disposed along a peripheral edge of the airtight sheet;
An intake vacuum pump coupled to the intake member;
Actuate the drain vacuum pump, drain the water in the ground through the vertical drainage member and the horizontal drainage member,
The improvement of the soft ground characterized in that the vacuum pump for intake is operated to discharge air entering between the airtight sheet and the ground from the peripheral portion of the ground through the suction member. apparatus.   2. The soft ground improvement device according to claim 1, wherein the intake member is embedded at a predetermined depth of the ground along the peripheral edge of the ground together with the peripheral edge of the airtight sheet. The intake member is disposed on a peripheral portion of the surface of the ground,
A vertical intake member is arranged in the vertical direction inside the ground at intervals along the peripheral edge of the ground,
The vertical intake member and the intake member are arranged to be connected so that air can be delivered,
The apparatus for improving soft ground according to claim 1, wherein the airtight sheet is laid so as to cover the surface of the horizontal drainage member, the intake member and the ground. Moisture in the ground is sucked by a plurality of vertical drainage members arranged in the vertical direction inside the ground to be improved,
It is arranged horizontally on the surface of the ground, and absorbs moisture in the ground by a plurality of horizontal drainage members connected so as to be able to transfer water with the vertical drainage member,
Laying so as to cover the horizontal drainage member and the surface of the ground, and sealing the ground surface with an airtight sheet in which the peripheral edge is embedded at a predetermined depth of the ground along the peripheral edge of the ground,
Inhale from the air intake member arranged along the peripheral edge of the airtight sheet and discharge it to the outside of the ground,
Actuate a drain vacuum pump connected to the horizontal drainage member, absorb water from the vertical drainage member and the horizontal drainage member, and discharge it to the outside of the ground.
The suction vacuum pump connected to the suction member is operated, and the suction member sucks air that enters between the airtight sheet and the ground from the peripheral edge of the ground and discharges it to the outside of the ground. An improved construction method for soft ground, characterized by   The soft ground improvement method according to claim 4, wherein the intake member is embedded at a predetermined depth of the ground along the peripheral edge of the ground together with the peripheral edge of the airtight sheet. The intake member is disposed on a peripheral portion of the surface of the ground,
A vertical intake member is arranged in the vertical direction inside the ground at intervals along the peripheral edge of the ground,
The vertical intake member and the intake member are arranged to be connected so that air can be delivered,
The said airtight sheet is laid so that the said horizontal drainage member, the said air intake member, and the surface of the said ground may be covered. The improvement method of the soft ground of Claim 4 characterized by the above-mentioned.

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