JPH01262999A - Method for solidifying weak soil by pressure feed of air - Google Patents

Abstract

PURPOSE:To efficiently solidify weak soil, by a method wherein a cementitious solidifying agent is injected in the dredged weak soil during the charge into a pressure feed tank and the weak soil containing the solidifying agent slurry is fed to a separate place under pressure by compressed air to be solidified. CONSTITUTION:Weak soil is discharged from a discharge port 5a to be continuously charged in a pressure feed tank 6 while the valve 16a of a slurry supply pipe 16 is opened and a pump 18 is driven to inject the solidifying agent slurry stored in a slurry tank 14 in the weak soil during charging. The weak soil after the injection of the slurry is kneaded by the blade 10a provided to a rotary shaft 10 in the pressure feed tank 6 to be mixed uniformly and sufficiently. The amount in the pressure feed tank 6 is detected by a sensor and, when the charging of the weak soil is stopped, compression air is supplied to the pressure feed tank 6 to feed the weak soil to the destination under pressure through a pressure feed pipe 19.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is for dredging soft soil such as sludge and sand deposited on the bottom of closed sea areas, rivers, lakes, dams, etc. The present invention relates to a method for rapidly solidifying the material by pressure-feeding it to a location.

[Conventional technology]

Conventionally, in order to transport dredged soft soil to another location such as a landfill (hereinafter referred to as destination), the dredged soft soil is loaded onto a special transport vessel using excavation equipment such as a backhoe or grab bucket installed on a barge. They carried it to the quay, temporarily stored it, and then transferred it to a truck or Gump truck and transported it to their destination.

However, according to this method, transshipment etc. are time-consuming, and problems such as so-called gunp pollution and the construction of construction roads occur during land transportation.

For this reason, recently, in addition to the excavation equipment, a pressure feed tank, a pressure feed device mainly consisting of an air compressor, and necessary auxiliary equipment have been installed on a barge floating on the water surface to remove stone blocks from the dredged soft soil. After that, it is kneaded to give fluidity to the soft soil, which is then put into a pressure transfer tank and is pumped using compressed air through a pressure transfer pipe that is piped over the water surface to a destination on land. A dredging pressure feeding system has been developed and is in use, in which water is discharged from a discharge port at the tip.

According to this dredging and pressure transport system, dredged soft soil can be transported efficiently without the trouble of transshipping soft soil or problems such as lump pollution.
(Can be pumped up to 3000m).

The transported soft soil will need to be solidified at the destination depending on the purpose of use at the destination, but if there is no urgent use for it such as in a landfill, and solidification is not urgent, it may take several years. Needless to say, it is best to leave it to dry naturally.

However, if the construction schedule for buildings or facilities on the reclaimed land is approaching, it is necessary to solidify the soft soil as soon as possible.

In such a case, when using the conventional method that does not use a dredging pumping system, a bit is installed near the quay, soft soil is poured into the bit, and then a cement-based solidifying agent (
Next, add the solidifying agent and (1), stir and mix (stirring is used for example when loading it into a gunp truck later), solidify it for several days, and solidify this solidified soft soil. Load it into a gun car or the like and transport it to the destination.

According to this method, the dredged soft soil can be solidified quickly, but just like the above method, loading the soft soil is time-consuming, and there are problems such as gunp pollution. This requires time and effort.

In addition, when using a dredging pressure delivery system, the soft soil is pumped to the destination through a pressure pipe and discharged, and at that destination, it is sequentially solidified in small areas by a solidification treatment device equipped with a solidifying agent addition device and a stirring device. A method of processing has been adopted.

[The invention tries to solve i! IB) According to the above-mentioned solidification method in the dredging pumping system, there are no problems such as the trouble of transshipping soft soil or pollution, but it does require a solidification treatment device, which requires production costs and costs for the solidification treatment work. This requires a lot of man-hours and days, and a great deal of cost.

The present invention solves the problems of the above-mentioned conventional method for quickly solidifying soft soil pumped by a dredging pumping system at the destination, and solidifies the pumped soft soil efficiently and effectively at low cost. The purpose is to provide a method that can be used.

[Means to solve the problem]

The present invention has been made to achieve the above objects,
In a dredging and pressure-feeding system for soft soil, comprising a step of charging dredged soft soil into a pressure-feeding tank, and a step of pumping the soft soil charged into the pressure-feeding tank with compressed air to another location via a pressure-feeding pipe and solidifying it. , characterized in that it has a step of injecting a cement-based solidifying agent slurry into the soft soil being put into the pressure-feeding tank; The VF feature includes the step of dropping the soft soil discharged from the discharge port through a cyclone and a shade.

[For production]

Since the slurry of the solidifying agent is injected into the soft soil being fed into the pressure transfer tank, it is possible to easily and reliably manage the solidifying agent injection 1, etc. according to the properties of the soft soil and jfLF, and the mixing after injection. This ensures uniform and sufficient mixing and improves the solidification effect.

In addition, since transportation to the destination is by force feeding through a pressure feed pipe, it is possible to discharge and solidify at the destination without requiring any trouble such as reloading.

Also, for example, when reclaiming water, if the discharged solidification agent and soft soil mixed with it are dropped into the water as is,
The solidifying agent that has been injected and mixed will separate and flow away, and the solidifying effect will be lost. However, a cyclone and a chute are installed at the discharge port to reduce the velocity of the soft soil, and the solidifying agent is further mixed with the solidifying agent in the chute. By filling the container with the soft soil and allowing it to flow out quietly by gravity, it is possible to prevent excess water from entering the container and maintain the solidification effect of the solidification agent injection even when the soil is dropped into water.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

(Example 1) FIG. 1 is a conceptual diagram showing an example of an apparatus in an example.

In FIG. 1, 1 is a hopper, which is equipped with a vibrating screen 2 above and a screw conveyor 3 below. 4 is a grab bucket that carries the dredged soft soil above hopper 1, then opens the packet and drops it onto vibrating screen 2. The dropped soft soil is removed by the vibrating screen 2 to remove large solids, falls into the bore hole 1 and is stored, and is sequentially kneaded by the lower screw conveyor 3, giving it a certain degree of fluidity and moving on to the next process. Sent.

In this embodiment, it is sent to a distribution screw conveyor 5 provided below. This screw conveyor 5 has a discharge port of 5m at both ends by rotating forward or backward.
, 5b, the soft soil can be alternately fed or discharged and sent to the next process.

Reference numeral 6.7 denotes a pressure feeding tank, which is installed in total of two units, one each below the discharge ports 5m and 5b of the screw conveyor 5, and communicates with the discharge ports 5m and 5b, respectively, via a connecting pipe 8.9. ν).

A rotary shaft 10.11 having a plurality of blades 10a and lla passes through the lower part of the pressure feeding tank 6.7, and the screw conveyor 5 connects the screw conveyor 5 to its discharge port 5m.
5b and the connecting pipe 8.9, the soft soil is kneaded to further improve its fluidity.

Furthermore, an air pipe 12.13 for supplying compressed air is connected to the upper part of the pressure tank 6.7 through valves 12m and 13m, and furthermore, an air pipe 12.13 for supplying compressed air is connected to the upper part of the pressure tank 6.7. Butterfly valves 8a, 9a are provided.

Reference numeral 14 denotes a slurry tank, in which, for example, in a land-based solidifying agent slurry production plant (not shown), a slurry produced by mixing a predetermined amount of solidifying agent and water is passed through hose 1.
After being transported at 5, it is stored for - hours. If necessary, a stirring device such as a rotary blade is provided inside to prevent solidification.

Slurry tank 14 and butterfly valve 8 of connecting pipe 8.9
a, discharge port 5m of screw conveyor 5 above 9a
, 5bl are communicated through a slurry supply pipe 16.17, and a pump 18 and valves 16a, 17a are provided in the middle.

Reference numeral 19 denotes a pressure feed pipe, which communicates with the pressure feed outlets 6a and 7m below the pressure feed tank 6.7 through valves 6b and 7b, and is supported by a 70-t floating on the water surface or by a column erected in the water. It extends to the land, and further extends to the destination on land, and opens the discharge port at the tip at the destination.

The above-mentioned parts, such as the hopper 1, the screw conveyor 3.5, the pressure tank 6.7, and the slurry tank 14, are all mounted directly on a barge (not shown) floating on the water or via a machine frame or a machine stand. It is arranged in such a way that
In addition, screw conveyor 3.5, rotating shaft 10.11
Rotating parts such as the above are driven by drive devices such as motors and speed reducers, which are not particularly designated by reference numerals.

Hereinafter, a method will be described in which dredged soft soil is pumped to a destination and solidified as it is using the dredging pumping system configured as described above.

When the pressure tank 6 is empty, the rotating shaft 10 is rotated, and the valve 6b on the discharge port 6a side is closed to close the butterfly valve 8a.
, and rotate the distribution screw conveyor 5 in the normal direction.
The soft soil stored in the hopper 1 and then kneaded and sent by the screw conveyor 3 is transferred to the left discharge port 5.
It is discharged from α and continuously introduced into the pressure tank 6 through the connecting pipe 8. At this time, the valve 16a in the slurry supply pipe 16
Open the slurry tank 1 and drive the pump 18.
The slurry of the solidification agent stored in the container 4 is injected into the soft soil being put in between the butterfly valve 8a and the discharge port 5a.

The soft soil into which the slurry has been injected is kneaded by the blades 10a provided on the rotating shaft 10 within the pressure feeding tank 6, and the soft soil and the slurry are mixed uniformly and sufficiently.

The pressure feeding tank 6 (also 7) has a total capacity of 9 m 3 , and when 5 m 3 of soft soil is poured into the tank, this amount is detected by a sensor (not shown) and the feeding of soft soil is stopped. do.

That is, the forward rotation of the screw conveyor 5 is stopped. At the same time, the butterfly valve 8a and the valve 16 in the slurry supply pipe 16
a is closed, the valve 12a in the air pipe 12 becomes a leap, and compressed air pressurized to 7 kg/am'' is supplied to the pressure tank 6 by an air compressor (not shown), and at the same time, the discharge port The valve 6b on the side 6a is opened, and the soft soil in the pressure feeding tank 6 is pumped through the pressure feeding pipe 19 with a diameter of 2501 mm.
Force feed to the destination 0m ahead.

Note that the compressed air may be optionally supplied auxiliary even in the middle of the pressure feed pipe 19.

Next, at the same time as the feeding of soft soil into the pressure-feeding tank 6 is stopped, the rotating shaft 11 of the other pressure-feeding tank 7 is rotated, the valve 7b on the discharge lower a side is closed, the butterfly valve 9a is closed, and the screw The soft soil sent from the screw conveyor 3 by reversing the conveyor 5 flows through the right discharge port 5b and is continuously thrown into the pressure feeding tank 7 through the connecting pipe 9. At this time, valve 1 in slurry supply pipe 17
The slurry in the slurry tank 14 is injected into the soft soil being put in between the butterfly valve 9m and the discharge port 5b at O-1 by the pump 18 which is being driven with the valve 7m open. The soft soil into which the slurry has been injected is mixed with the blades 11a provided on the rotating shaft 11 within the pressure feeding tank 7, and the soft soil and the slurry are mixed uniformly and sufficiently.

The amount of soft soil thrown into the pressure tank 7 is the specified amount (6 m')
When it reaches this point, the screw conveyor 5 stops rotating in reverse due to the action of the sensor, and the feeding of soft soil stops. At the same time, the butterfly valve 9a and the valve 17a in the slurry supply pipe 17 are closed, the valve 13a in the air pipe 13 is opened, and compressed air is supplied into the pressure tank 7, and at the same time, the discharge lower agA
The valve 7b is opened, and the soft soil mixed with the slurry in the pressure-feeding tank 7 is force-fed to the destination via the pressure-feeding pipe 19.

When the feeding of soft soil into the pressure feeding tank 7 is stopped, the feeding of soft soil into the pressure feeding tank 6 is started, and so on, by repeating the same operation as described above, the slurry is alternately poured into the pressure feeding tank 6.7. The soft soil mixed with the soil is pumped and continuously discharged from the discharge port of the pumping pipe 19 for reclamation at the destination.

Forward/reverse operation of the screw conveyor 5, various valves 6b
, 7b, 8a, 9a, 12a, 13a.

The opening and closing of 16m and 17m can be electrically controlled for automatic operation. However, the rotating shaft 10.11 in the pressure feeding tank 6.7 and the pump 18 do not repeatedly stop and stop pumping, and may be operated constantly during the pumping operation, or may be operated at appropriate intervals depending on the nature of the soft soil. Good too.

The soft soil discharged from the pressure feed pipe 19 at the destination gradually solidifies in a short period of time. The number of days, strength, etc. for this solidification are determined depending on the purpose of use of the destination.
By adjusting and subtracting, 51 is adjusted.

Solidified M is manufactured by cement manufacturers, etc.
For example, there are commercially available products for various uses such as soft soil, sludge, and ultra-soft soil, so select one according to the above-mentioned uses.

The amount added is determined depending on the nature of the soft soil, water content ratio, purpose of use, etc.

For example, in order to make the 7-day strength (the compressive strength of one wheel when the discharged soft soil is opened 7 times) to be 0.5 to 1 ky/cwt', which is enough for construction machines such as bulldozers to run, In the case of soft soil with a water content of 100% (weight ratio of water and soft soil) in silty soil, place 7 on 1 m3 of soft soil.
Add 0-120 ky/am'' of solidifying agent.

FIG. 3 shows the test results regarding the relationship between the amount of solidifying agent added and single wheel compressive strength (7-day strength).

The numbers in parentheses in the figure are the water content ratios of the collected samples.

As can be seen in FIG. 3, in order to obtain high strength, it is generally necessary to add a large amount of solidifying agent to softer materials with higher water content. However, there are layers of sediment in the water, and these layers change depending on the depth of excavation, and when the layers change, the water content ratio and soil quality also change. Of course, the condition of the layer, its water content ratio, and soil quality also change depending on the water area to be excavated. Therefore, when adding a solidifying agent to dredged soft soil, the amount to be added is determined by understanding the properties of the soft soil by taking samples at appropriate times.

The solidifying agent is added as a slurry as described above, and this slurry is generally used in a water/solidifying agent ratio of 1:1 (weight ratio).

In this embodiment, as described above, the injection for adding the solidifying agent is carried out by feeding the slurry sent through the slurry supply pipe 16 into the connection 1ffs near the butterfly valve 8a, and passing it through the connection pipe 8 into the pressure feeding tank 6. Slurry supply pipe 1
6 may be connected to the pressure-feeding tank 6, and injected into the pressure-feeding tank 6 so that it falls on the soft soil that has been put into the tank from the connecting pipe 8 (the same applies to the pressure-feeding tank 7IlI). In other words, in any case, it is preferable to pour the slurry into the soft soil being put into the pressure feeding tank 6 (7) in order to ensure that the soft soil and the slurry can be mixed uniformly and sufficiently.

(Example 2) Figure PJ2 is a diagram of the vicinity of the discharge port showing another example of the present invention, in which (a) is a plan view and (b) is a front view.

As in Example 1, after injecting and mixing the solidifying agent slurry into the dredged soft soil, it is forced to the destination through the pressure feed pipe 19, and the soft soil is discharged from the discharge port at the tip of the pipe 19, and is buried, for example, in water. If the discharged soft soil is directly put into water when performing erecting, the solidification agent mixed in the soft soil will decompose and be washed away, and the solidification effect will be lost.

In such a case, as shown in FIG.
is provided on the discharge port side of the pressure feed pipe 19, and the soft top is dropped into the water bottom 22 via the cyclone 21 and the chute 20.

In other words, the soft soil discharged from the discharge port of the pressure feed pipe 19 descends inside the cyclone 21 while turning as shown by the arrow, so that the momentum (discharge energy) such as the velocity when discharged is reduced, and the soft soil is discharged from the chute. 20, the chute 20 is filled with the liquid, and the liquid gradually flows and accumulates due to gravity.

Therefore, the solidification agent mixed with the soft soil will not be separated from the soft soil and washed away, nor will excess water be mixed in, and the same solidification effect as on land can be achieved.

In addition, as land reclamation progresses, salt from soft soil thrown into the water 82
When the water becomes large and the bottom becomes shallow, use chute 20.
are raised one after another and adjusted so that the lower end of the chute 20 is at an appropriate position above the water bottom.

[Effects of the Invention] Since the present invention has the above-described configuration, it has the following various effects.

(1) Since the soft soil and the solidification agent can be sufficiently mixed with high efficiency, the soft soil becomes uniform in texture and has a great solidification effect.

(2) The amount of solidifying agent added can be reliably controlled, and
Since a fixed amount is mixed in a pressure-feeding tank, quality control in terms of softness can be completely controlled.

(3) Soft soil can be transported and solidified continuously without requiring any trouble such as reloading. Therefore, when the method of the present invention is used for land reclamation, the construction period can be shortened, and since the solidification effect is large, early utilization is possible, and construction costs can be reduced.

(4) Since the soft soil is pumped using a pressure pipe, there will be no environmental problems such as odor or traffic obstruction.

(5) A cyclone upstream chute is provided at the discharge port of the pressure-feeding pipe, and the solidification effect of the soft soil placed in water can be maintained by adding a process of dropping the discharged soft soil through the cyclone and chute. It is.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing an example of a device according to an embodiment of the present invention, Fig. 2 is a diagram showing the vicinity of the discharge port of a pressure feeding pipe showing another embodiment, (,) is a plan view, and (b) is a The front view and FIG. 3 are diagrams showing the relationship between the amount of solidifying agent added and the Itsumugi compressive strength. 1: Hopper, 2: Vibrating screen, 3 Niskrieu conveyor, 4 Nigelab packet,
5: Distribution screw conveyor,
6.7: Pressure feeding tank, 8.9: Connecting pipe,
10.11: Kaisatsu glaze, 12.13: Air piping,
14: Varnish-free tank, 16.17: Nislery supply pipe, 19: Pressure feed pipe, 20: Chute, -21: Cyclone agent Patent attorney Takayoshi Honma 2 Figures (a) (b) Rod, ? Figure □Reihii ratio θθ rock--Image IK ratio 100% 60 Ri θ 120 160
SonoA Administrative Agent Nonoral Amount Re/m Procedure Amendment (0 button June 8, 1988 1, SO, 1'r Director General Kunio Ogawa Tono 1, 1i- Indication of 1988 Patent Application No. 91265 No. 2, Title of the invention: Method for solidifying soft soil by pneumatic conveyance 3, Relationship with the case of the person making the amendment Patent Application Daisakusho
2-1-48 Nionohama, Otsu City, Shiga Prefecture, 4゛
Person 〒100 Telephone 03-242-3800
(Alternative) 5. Subject of correction ■Correct content 1. Correct "(weight ratio of water to soft soil)" in the 3rd line directly below line 14 of the specification to "(weight ratio of water to earth and sand)" . 2. Delete r/C, 2J in the bottom two lines of the same book. that's all

Claims (2)

[Claims] (1) A process of putting the dredged soft soil into a pressure tank,
In the dredging and pumping system for soft soil, which comprises a step of pumping the soft soil charged into the pressure feeding tank to another location via a pressure feeding pipe using compressed air and solidifying it, cement is added to the soft soil being put into the pressure feeding tank. A method for solidifying soft soil by pneumatic feeding, the method comprising the step of injecting a solidifying agent slurry. 2. The method for solidifying soft soil by pneumatic feeding according to claim 1, further comprising the step of dropping the soft soil discharged from the discharge port through a cyclone and a chute provided on the discharge port side of the pressure pipe.