JPH07103549B2 - Construction method and equipment for laying sand on soft ground - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a method for laying sand on a clayey soft ground by dredged embankment and an apparatus used in the method.

"Conventional technology" The following methods are used as a sand laying method for reinforcing soft ground.

(1) A construction method in which the ground surface soil is hardened with a mud hardening agent (kneading of dehydron, cement, lime, etc.) and then sand is applied.

(2) A surface layer where nets, sheets, etc. are stretched over the entire construction area, fixed around it, and reinforced with ropes, etc. to prevent local collapse, and then be constructed with sand so that it can pass after construction. Processing method.

(3) A method in which sand is pumped from a barge or the like by a pump ship from a barge or by a sand pump from a sand pocket through a sand pipe that is laid on land, along with seawater, and into the cover soil (laying sand) area. In this method, a sand spreader is attached to the discharge port of the sand sending pipe to scatter sand, or a small diameter pipe is connected to the discharge port of the sand sending pipe to move the sand evenly.

(4) Embankment around the soil cover area and fill the area with seawater,
This is a construction method in which a sand-blasting boat is floated and the entire sand is sprayed.

(5) Depending on the condition of the land cover, a method of transporting the sand directly into the soil cover area by dump truck, unwinding the sand with a bulldozer, etc. and spraying it.

"Problems to be solved by the invention" (1) Equipment is required for the use of a mud hardening agent, which results in high construction costs and local construction.

(2) The method of putting nets and sheets in the construction area requires materials, manpower and labor.

(3) The method of diffusing sand with the seawater from the discharge port of the sand pipe is, depending on the condition of the ground, until the sand rises near the discharge port (diffusion gradient 1:30 to 1:60). The soft ground there could not bear the load of sand, the sand began to slip in, the surface part moved laterally, and the ground collapsed and collapsed rapidly, and it spread to the surrounding ground and finished. The applied sand layer is also involved, and the clay in the surface layer returns to the place where it was depressed, and the sand that has been sent disappears. In addition, the soft ground that cannot be walked by people also cracks on the surface due to the passage of time from embankment construction, the elimination of water retention during that period, and the drying in summer, etc., and the surface is hardened to a depth of 10 cm to 30 cm. It becomes possible to walk. When seawater that exceeds 4 times the volume of sand is sprayed together with sand through a sand pipe to such a walkable ground, the hardened topsoil is softened, and the seawater that has penetrated from the cracks is clayey at the bottom of the sand layer. Loosen the ground, reduce shear resistance, make lateral movement and collapse easier, and make sand laying difficult.

(4) The method of constructing a bank and filling the area with seawater and floating a sand-breaking ship requires a large-scale banking work, and also requires carrying the sand-breaking ship into the area.

(5) The method of transporting by land with a dump truck and unwinding with a bulldozer, etc. does not work in the soft ground area where the dump truck cannot pass, and it is a small-scale construction.

"Means for solving the problem" The sand to be thrown into the sand blower is sent to the sand blower pipe that is in communication with the sand drop pipe provided at the bottom of the sand blower main unit. Is a method of spraying,
The lower part of the cylindrical sand blower body is squeezed into a funnel shape to provide a sand drop pipe, and a damper that can adjust the flow rate of sand and air is provided on the sand drop pipe to communicate with the sand drop pipe. , The main blower is connected to the end of the sand sending pipe protruding from the sand sending machine main body, and one end of the lower air sending pipe is placed between the connecting position of the air sending pipe and the sand dropping pipe and the main blower connecting position of the sand sending pipe. Communication,
Connect the other end to the sub blower, connect the upper blower pipe to the sub blower, and let the upper blower pipe face the inside of the sand blower main body.
A vibrator is provided on the lower inner wall surface of the sand blower main body, and
A device equipped with an air vent pipe that communicates with the inside of the sand blower body to the outside air does not apply drop pressure or vibration of sand to soft ground, and evenly distributes sand with air without weakening the ground with water. The purpose is to

[Operation] Sand transported by barge, gut boat, etc. is unloaded, and is transported to the soil cover area by dump truck. It is dispersed and temporarily placed near the embankment surrounding the soil cover area.
A sand blower is installed on the embankment and a temporary sand hopper is installed. Temporary sand is put into the sand hopper by a shovel car, and then the sand is thrown into the sand blower. At this time, the sand drop tube is blocked by a damper. When the main blower is started, air flows through the sand pipe, and the lower part of the damper of the sand drop pipe is pressurized.

Next, when the sub-blower is started, air flows from the upper air supply pipe into the sand blower main unit, and the air fills the sand inside the sand blower main unit, but excess air is discharged to the outside by the air vent pipe. To be done. When the air pressure gauge reads that the air pressure in the upper air pipe is higher than the air pressure in the sand drop pipe, the damper is gradually opened, and the air flow flows from the tip of the upper air pipe to the sand drop pipe, and with the sand. The sand flows into the sand transfer pipe, blows the sand out of the discharge port, and spreads the sand. The vibrator is activated to vibrate the sand inside the sand transfer machine.

[Embodiment] An embodiment of the device according to the present invention will be described with reference to FIGS. 1 and 2. A sand dropping pipe (1a) is formed by squeezing the lower portion of a cylindrical sand feeder body (1) into a funnel shape. ) To form. Sand drop tube (1a)
A damper (2) is installed on the neck of the
A pinion gear (3) that meshes with a) to move the damper (2) forward and backward is pivotally supported on the support base (4), and the pinion gear (3)
Attach the handle (5) to and manually move the damper (2) back and forth. A main blower (7) is connected to the end of the sand transfer pipe (6) which communicates with the sand drop pipe (1a) and projects from the sand transfer machine body (1). Since the socket part (6a) is formed at the tip of the sand transfer pipe (6) and the other sand transfer pipes (6) are sequentially added, it is optional to form the other sand transfer pipes (6) flexibly. Can be laid in the direction of. Further, a check valve (8) for preventing the sand from flowing back to the main blower (7) is provided in the sand sending pipe (6) in the vicinity of the connection point between the sand sending pipe (6) and the main blower (7). Connection part between sand transfer pipe (6) and main blower (7), sand transfer pipe (6) and sand drop pipe (1)
At the intermediate position with the connecting part of a), the lower air supply pipe (9) is connected to the sand transfer pipe (6), the upper end of the lower air supply pipe (9) is connected to the sub-blower (10), and the upper air supply pipe (11) is connected. ) Is connected to the sub-blower (10), the other end is hung from the top of the sand blower main body (1) to face the main body, and the fumarole (11a) is formed at the lower end. A vibrator (12) consisting of a vibrating plate (12a) and a vibrating rod (12b) is attached to the inner wall of the funnel-shaped lower part of the sand feeder main body (1), and inside the sand feeder main body (1). Ring-shaped air vent pipe (1
3) is laterally fixed with the support rods (14), and several through holes (13a) are bored in the air vent pipe (13) and the mesh (1
3b) is attached to prevent sand from entering the air vent pipe (13), and the rising part (13c) is formed from the pipe, and the tip of the rising part (13c) is placed outside the sand blower body (1). Make it protrude. In the figure, (1b) is a sand inlet, (1c) is a sand receiving plate, (15) is a sand hopper, (16) is a power source, and (17) is an air pressure gauge.

The method of the present invention, as shown in FIGS. 3 and 4, is sand (19) transported by sea from a barge or gut ship (18).
Landing and dumping truck (21) to the soil cover area (20)
It will be transported by land and distributed and temporarily placed near the embankment (22) that surrounds the soil cover area (20). The sand blower main body (1) is installed on the embankment (22), the temporary sand hopper (15) is installed, and the temporarily placed sand (19) is thrown into the temporary hopper (15) by the shovel car (23). Sand (19) sand feeder body (1)
Throw in. At this time, the sand drop tube (1a) is replaced by the damper (2)
Is blocked by. When the main blower (7) is started, air flows in the sand transfer pipe (6), and the lower part of the damper (2) of the sand drop pipe (1a) is pressurized. Sub Blower (10)
When air is started, air flows from the upper air supply pipe (11) into the sand blower main body (1), and the air fills the sand (19), but excess air is generated by the air vent pipe (13). It is released to the outside. The air pressure gauge (17) (1) indicates that the air pressure in the upper air supply pipe (11) is higher than the air pressure in the sand drop pipe (1a).
After reading with 7), open the damper (2) gradually,
The flow of air flows from the fumarole (11a) provided at the tip of the air supply pipe (11) to the sand drop pipe (1a), and together with the sand (19) to the sand supply pipe (6), the sand (19). Sand from the discharge port and spreads sand to the soil cover area (20).
Other sand transfer pipes (6) ... are added to the socket part (6a) formed in step 2 and the sand is spread to a distant place. Further, since the sand pipe (6) can be flexibly replenished, the sand can be spread over a wide area by the swinging motion. The sand content of the air to be sent is
The optimum value is 10% to 15%, but it may vary slightly depending on the water content of sand and the sand feeding distance. If the vibrator (12) provided in the sand blower main body (1) is appropriately operated, the sand (19) may smoothly flow into the sand drop pipe (1a) and be accumulated in the main body to become unflowable. Absent. Further, the sand (19) falling from the sand drop pipe (1a) does not flow back to the main blower (7) by the air supply from the lower air supply pipe (9). (24) in the figure is a draining plate.

[Advantages of the Invention] The present invention is thus formed, and since the sand is sprayed by the air, the ground is not subjected to a drop pressure or vibration, and is not softened by water, and the ground is clogged with sand. Prevent the ground from moving laterally stably. The distribution of sand is easy because it uses a lightweight PVC pipe, and the pipes can be connected and disconnected easily, so that the piping can be performed quickly and easily. In addition, since the pipe can be easily extended, sand can be evenly distributed over the entire surface of the soil cover area, and the sand thickness can be confirmed, so that sand can be prevented from sinking into or sinking. Since sand is sent by air, it is not necessary to provide a drainage route or a water outlet in the soil cover area, sand can be sprayed from any position, and the construction period can be significantly shortened by installing multiple sand blowers. Further, the sand blower itself has a robust structure and is rich in durability, reliable operation, no failure, and easy to manufacture.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of an apparatus according to the present invention,
FIG. 2 is a view on arrow A in FIG. 1, FIG. 3 is a front view showing an embodiment of the method of the present invention, and FIG. 4 is a plan view of the same. (1) …… Sand blower body, (1a) …… Sand drop tube (1b) …… Sand inlet, (2) …… Damper, (6) ……
Sand blower (7) …… Main blower, (9) …… Lower blower pipe (10) …… Sub blower, (11) …… Upper blower pipe (12) …… Vibrator, (13) …… Air vent pipe

Claims (4)

[Claims] 1. The sand to be thrown into the sand blower is sent by the pressure air sent from the main blower to the sand blow pipe communicating with the drop pipe of the sand provided at the bottom of the sand blower main body, and is sprayed to the soil covering area. A method of laying sand on soft ground. 2. A sand dropping pipe is provided by squeezing a lower portion of a cylindrical sand blower body into a funnel shape, and a damper capable of adjusting a flow rate of sand and air is provided in the sand dropping pipe. Communication,
In addition, connect the main blower to the end of the sand sending pipe protruding from the sand sending machine main body, connect the upper air sending pipe to the sub blower so that it faces directly above the sand dropping pipe, and communicate with the outside air to the sand sending machine main body. A device for laying sand on soft ground that has an air vent and a sand inlet. 3. The apparatus for laying sand on soft ground according to claim 2, wherein a vibrator is provided on the lower inner wall surface of the sand blower main body. 4. The sand sending pipe is formed by connecting an air sending pipe extending over the sub blower between the sand dropping pipe connecting position and the main blower connecting position. Equipment for laying sand on the soft ground of.