JP2004092386A5 - - Google Patents

Description

Improved soil casting method

The present invention relates to improved soil striking setting method as with the addition of solidifying material to sand flowability modified soil by kneading and pouring continuously to the bottom of the water and transported downwards through the transfer tube from the hitting設船to the sea bed About.

In port construction such as reclamation of coastal sea areas and creation of artificial islands, a slurry-like fluidity-improved soil obtained by adding and cementing cement-based solidifying material and water to dredged sand and other sand from the seabed and the like is used for plant ships. Forcibly transported from the kneading facility to the casting vessel, the improved soil is allowed to flow down from the casting vessel through the transfer pipe to the bottom of the disposal site, and the improved soil is cast at the bottom from the lower end outlet of the pipe and solidified. A method of causing the above-described method is conventionally known (for example, see Patent Document 1 below).
JP 2000-129652 A

  By the way, in such a conventionally known casting method, the above-mentioned improved soil flows down the transfer pipe relatively slowly due to its own viscosity, and heads toward the water bottom, and is slowly and continuously discharged from the lower end outlet of the transfer pipe to be discharged. However, conventionally, since a substantially straight pipe including the outlet portion is used as the transfer pipe, the following problems have been found.

  That is, when the improved soil is poured, the improved soil is continuously discharged from the lower end outlet in the transfer pipe. At that time, for example, as shown in FIG. External seawater may enter the pipe near the inner wall from the lower end. The infiltrated seawater gradually rises backward along the inner wall of the pipe due to a difference in specific gravity with the improved soil (soil and sand), and mixes with the improved soil near the inner wall of the pipe to lower its viscosity (see FIG. b)).

  As a result, as shown in FIG. 7 (c), the improved soil near the outlet of the transfer pipe is peeled off from the improved soil on the upper side of the transfer pipe, so that the improved soil rapidly (i.e., at a speed higher than the normal flow speed). ) It starts to descend, and the seawater rises backward in the pipe by the descending amount. As shown in FIG. 7 (d), the raised water tends to invade between the improved soil on the upper side and the inner wall of the transfer pipe, and the upper improved soil is further increased by the same operation as described above. It comes off from the improved soil on the upper side and starts to descend rapidly in the pipe, and the seawater further flows upward in the pipe by the amount of the fall.

  When this is repeated, the seawater flows back up to a considerable height in the transfer pipe, and in such a state, the improved soil falling in the transfer pipe will have a large amount of soil in the pipe before it reaches the lower end outlet of the pipe. The water is sufficiently mixed with the seawater, and a considerable amount of sediment separates from the solidified material in the pipe. However, such sedimentation of sediment in the transfer pipes is caused by (1) slowing down the speed of solidification of the improved soil (sediment) poured into the water bottom, (2) the solidification strength is not sufficient, (3) A large amount of liberated solidified material may cause problems such as polluting the water area around the landfill site.

  The problem of the backflow of seawater into the transfer pipe described above occurs when the supply speed of the improved soil from the casting vessel to the transfer pipe is particularly low (therefore, the supply amount is small) or when the supply is intermittently performed. This is particularly noticeable when the supply is interrupted.

The present invention has been made in view of the above circumstances, and so can be effectively solved by a simple construction problems seawater backflow into the transfer tube, and an object thereof is to provide an improved soil hitting set method .

In order to achieve the above object, the invention of claim 1 is to store a viscous fluidity-improved soil obtained by adding and solidifying a solidifying material to earth and sand in a surge tank on a cast-in ship, and the fluidity is improved from the bottom of the surge tank. The improved soil gradually flows under its own weight into the upper part of the transfer pipe whose lower end extends to the bottom of the water, and the fluidity-improved soil that flows and descends in the transfer pipe by its own weight is continuously struck from the outlet at the lower end of the transfer pipe to the bottom of the water. a modified soil hitting設方method to allow setting, the the transfer tube Rutotomoni mounted off valve capable of opening and closing the outlet of the tube, this opening and closing valve, for holding this closed position The urging means for applying the urging force in the valve closing direction to the valve is connected, and when the fluidity-improved soil is poured, the fluidity gradually flowing from the bottom of the surge tank into the transfer pipe by its own weight. the opening force the weight of the modified soil is on the on-off valve By opening the on-off valve against the urging force of the urging means, the fluidity-improved soil is continuously discharged from the outlet of the transfer pipe while preventing backflow of water into the transfer pipe, If the supply of fluidity-improved soil from the surge tank to the transfer pipe cannot keep up, the fluidity-improved soil remaining in the transfer pipe is reduced to a predetermined limit amount and the valve opening based on the weight of the improved soil is performed. As the force decreases, the on-off valve closes again by the urging force to prevent backflow of water from the outlet into the transfer pipe .

According to the above feature, in the state in which submerged the transfer tube into the water, when there or when small amounts there is no improved soil on the tube, said opening and closing valve, a biasing force of the water pressure and the biasing means acting to Ru is held in the closed position by the valve closing force based on. From this state, the casting process starts, and the improved soil is supplied from the casting boat to the upstream part of the transfer pipe, and when it flows down near the outlet, its weight exerts a valve opening force on the on-off valve. will, when the valve opening force exceeds the limit value, the on-off valve is operated to open valve against the urging force and pressure of the biasing means, so that modified soil is gradually discharged from the transfer tube outlet. Even after opening thereof, for proper valve closing force based on the biasing force of the biasing means to the opening and closing valve is applied, improved soil while preventing backflow of water into the transfer tract by an appropriate amount from the outlet of the transfer pipe It is exhaled gradually and is put on the bottom of the water.

During such a casting process, the supply speed of the improved soil from the casting ship into the transfer pipe becomes extremely slow, or the supply of the improved soil is intermittently performed and the supply is temporarily interrupted. If there is, in such a case, not catch up the improved soil replenished from the hitting設船the modified soil discharged from the transfer tube outlet, although remaining amount of the modified soil transfer tube is gradually reduced, When the remaining amount decreases to a predetermined limit amount (for example, a remaining amount of about 1 to 2 m upstream from the outlet in the illustrated example), the on-off valve closes again based on the urging force of the urging means, and the transfer pipe is moved. Shut off exit.

Thus, during the casting process and during standby, a large amount of water does not flow backward from the lower end outlet into the transfer pipe, and the improved soil flowing down the transfer pipe from the casting boat to the bottom of the water is not There is almost no danger that water will mix with water in the pipe before it reaches the pipe outlet. Therefore, it is necessary to effectively prevent sediment in the improved soil from mixing with water in the transfer pipe and separating from solidified material. Can be. Thereby, the improved soil in a proper state in which the sediment is not separated (that is, the soil and the solidified material are sufficiently mixed) can be poured from the outlet of the transfer pipe into the water bottom in an appropriate amount. The soil (sand) can be solidified quickly and firmly, and the liberation of the solidified material from the soil is minimized as much as possible. It is valid .

As described above, according to the present invention, the viscous fluidity-improved soil is stored in the surge tank on the casting vessel, and the fluidity-improved soil is gradually flown by its own weight into the transfer pipe from the bottom of the surge tank. In the improved soil casting method in which the fluidity-improved soil that flows and descends in the transfer pipe by its own weight can be continuously poured into the water bottom from the outlet at the lower end of the transfer pipe, the soil is gradually moved under its own weight from the bottom of the surge tank into the transfer pipe. By opening the on-off valve against the urging force of the urging means by the valve-opening force exerted on the on-off valve by the weight of the fluidity-improved soil that has flowed into the water, the backflow of water into the transfer pipe is prevented. While the fluidity-improved soil is continuously discharged from the outlet of the transfer pipe while the supply of the fluidity-improved soil from the surge tank to the transfer pipe cannot keep up with the flow-improved soil remaining in the transfer pipe, Is reduced to the specified limit and the improved soil In response to the valve opening force is reduced based on the weight, the opening and closing valve by operating again closed by the urging force is, since to be able to prevent backflow of water into the transfer tube, even during the pouring process, Also, during standby, there is no danger that a large amount of water will flow back up from the outlet into the transfer pipe, and the improved soil flowing down in the transfer pipe may mix with water in the pipe before it reaches the pipe outlet. Since this is almost eliminated, it is possible to continuously pour an appropriate amount of improved soil in which sediment is not separated from the lower end of the transfer pipe into the water bottom in an appropriate amount , thereby quickly placing the improved soil. Also, it can be solidified firmly and the amount of solidified material released from the earth and sand at the time of casting is minimized as much as possible, so it is also effective in preventing pollution of the water area around the casting disposal site due to the diffusion of the solidified material It is. Thereon, in order to automatically open and close the closing valve, the valve only needs to simply connecting the biasing means to impart the closing biasing force thereto, especially the expensive control means for controlling the automatic opening and closing Since there is no need to provide such a device, it is possible to contribute to simplification of the structure of the device and, eventually, cost reduction.

According particularly to the second aspect of the present invention, since including a holding mechanism capable of locking at any time in a position closing the opening and closing valve can be held securely in the closed position the closing valve by actuating the upper Symbol holding mechanism, thereby Even when the transfer pipe is moved up and down near the water surface, the outlet of the pipe can be reliably closed, and the backflow of water into the pipe and the discharge of improved soil from the pipe outlet can be reliably prevented .

  Hereinafter, embodiments of the present invention will be specifically described below based on examples of the present invention illustrated in the accompanying drawings.

  FIG. 1 is a schematic plan view showing an example of a system for transporting and setting improved soil, FIG. 2 is an enlarged side view along line 2-2 in FIG. 1, and FIG. 3 is a transfer pipe according to a first embodiment of the present invention. FIG. 4 is an enlarged view of a main part of the casting boat using the slab (an enlarged view as viewed in the direction of arrow 3 in FIG. 2). FIG. FIG. 5 is a longitudinal sectional view showing a leading end of the transfer pipe according to the second embodiment, and FIG. 6 is a longitudinal sectional view showing a leading end of the transfer pipe according to the third embodiment.

1 and 2, the embankment B includes a landfill area A ₁ having a landfill Gr as disposal sites, to partition between the surrounding area A _2, which is erected building on the seabed, its surrounding area A the _2, it processes vessels SW (see Japanese Patent Laid-Open No. 7-76454) for wind transport are tethered together added by kneading hardening material dredged material. On one side of the processing vessel SW, a large amount of sediment that is dredged elsewhere, the peripheral area A soil luck Vessel SE which has been transported to ₂ is alongside, in yet another side of the processing vessel SW is solidified A solidified material plant ship SP that produces a cement slurry in which cement as a material is kneaded with water is aboard.

  The dredged sediment in the earth transport ship SE is put into the hopper 34 of the processing ship SW by the earth lift (backhoe) 33 mounted on the processing ship SW, and in parallel with this, the solidified material plant ship The cement slurry generated by the SP is continuously injected into the hopper 34.

In the processing vessel SW, in the processing chamber below the hopper 34, the dredged soil is crushed and mixed with the cement slurry by stirring, and the compressed air obtained by rotating the rotor in the processing vessel SW and driving the compressor is used. Then, the crushed mixture of dredged soil and cement slurry, that is, the improved soil S, is forcibly transported to the floating discharge pipe 6 by a plurality of float pipes 8 connected to the processing chamber outlet. Haiokukan 6 have been extended to the landfill area A ₁ overcame embankment B, it is conveyed to a punch設船SS that are tethered to the landfill area A _1.

  From the casting vessel SS, the improved soil S is drowned continuously through the transfer pipe 12 into the disposal site, that is, the water bottom E of the landfill Gr, without separation of the dredged soil and cement slurry, as will be described in detail later. You.

  Next, with reference mainly to FIGS. 3 and 4, a specific structure of the improved soil casting device D installed on the casting boat SS will be described.

  On the hull 1 of the casting boat SS, a surge tank 10 and a cyclone 3 erected integrally on the tank 10 are fixedly supported. The cyclone 3 has a closed-cylindrical cyclone main body 3b, an inlet 3i is opened at an upper portion on one side, an outlet 3o is opened at a lower portion thereof, and an air separation chamber 3s is provided at the center of the upper wall. . The upper end of the air separation chamber 3s is connected to the air duct 5, and a discharge port 5o that opens to the atmosphere is opened at the outer end of the air duct 5. An outlet 6o of a discharge pipe 6 extending from the processing boat SW is connected to an inlet 3i of the cyclone 3.

  The improved soil S transported by wind in the discharge pipe 6 enters the cyclone 3, and after the air mixed therein is separated, flows toward the surge tank 10 below the cyclone body 3b.

  In the upper wall of the surge tank 10, an inlet 10i that directly communicates with the outlet 3o of the cyclone 3 is opened, and the bottom wall 10f is formed in a funnel shape, and the outlet 10o is opened at the lowermost portion. The improved soil S separated from the air in the cyclone 3 flows to the surge tank 10 by its own weight and is stored in the tank 10, and further flows from its bottom into the transfer pipe 12 below the tank by its own weight.

  The transfer pipe 12 is mounted on the hull 1 via a pivot 15 with a support frame 17 integrally provided along the upstream end of the transfer pipe 12, so that the hull 1 is at an arbitrary inclination angle (for example, 0 ° with respect to the water surface). (In a tilt angle range of degrees to 90 degrees). The upper part in the transfer pipe 12 and the bottom outlet 10o of the surge tank 10 are connected via a telescopic type connection cylinder part 14 which can expand and contract along an arc centered on the pivot 15; The improved soil S in the surge tank 10 flows down into the transfer pipe 12 by its own weight via the connection tube portion 14. In addition, an opening / closing valve (not shown) capable of arbitrarily adjusting the amount of the improved soil S flowing from the inside of the tank 10 toward the transfer pipe 12 may be provided at the bottom outlet 10o of the surge tank 10.

  An actuator 16 such as a hydraulic cylinder is interposed between the support frame 17 of the transfer pipe 12 and the hull 1, and the transfer pipe 12 is forcibly swung around the pivot 15 by the actuator 16. Of the transfer pipe outlet 12o can be arbitrarily adjusted. The transfer pipe 12 extends obliquely downward and substantially straight toward the water bottom E, and the improved soil S is directly poured into the water bottom E from a lower end outlet 12o thereof.

  An on-off valve V that can open and close the outlet 12o of the transfer pipe 12 is attached to the front end of the transfer pipe 12. The opening / closing valve V is supported via a pivot P by a support bracket 12b integrally extending on the outer surface of the upper wall near the outlet 12o of the transfer pipe 12, whereby the valve V is connected to the outlet of the transfer pipe 12. It is rotatable around the pivot P between a closed position Va that sits on the opening edge of the opening 12o to close the outlet 12o and a predetermined opening position Vb that is separated from the opening edge and opens the outlet 12o. The opening position Vb is regulated by a stopper mechanism (a stopper 12s integrally connected to the support bracket 12b in the illustrated example) provided between the on-off valve V and the transfer pipe 12, whereby the on-off valve V is moved. It does not open more than a predetermined opening degree, that is, more than the opening position Vb. The predetermined opening can be set arbitrarily, for example, can be set to about 90 degrees.

  The on-off valve V is made as thin and light as possible so that the moment in the valve opening direction or the valve closing direction acting on the valve V about the pivot P based on its own weight and buoyancy can be substantially ignored. You.

  The on-off valve V is connected to a float F as an urging means for receiving a buoyancy for urging the same in the valve closing direction in the water, and the float F is an outer surface near the free end of the on-off valve V in the illustrated example. Are integrally connected to the body. The on-off valve V is normally operated by a closing force based on the water pressure applied to the valve V and the buoyancy of the float F in a state where the transfer pipe 12 can be submerged in the water and the improved soil S can be poured on the bottom of the water. Is held at the closed position Va, but the valve opening operation is performed when the valve opening force applied to the valve V exceeds the valve closing force based on the weight of the improved soil S in the transfer pipe 12 in the casting step described later. Note that the mounting position of the float F with respect to the on-off valve V and the position of the pivot P are determined by the buoyancy of the float F regardless of whether the on-off valve V is at any rotational position between the closed position Va and the open position Vb. Is desirably set to act as a valve closing force on the valve V.

  Further, the opening / closing valve V is connected to a holding mechanism H capable of locking the opening / closing valve V to the closed position Va at any time. In the illustrated example, the holding mechanism H is provided with an operation lever (not shown) having a lock mechanism disposed on the casting boat SS, and an outer surface of the transfer pipe 12 for interlocking connection between the lever and the on-off valve V. And an operation wire 30 routed along. Therefore, by pulling the operation wire 30 in the closing direction of the on-off valve V via the operation lever on the casting boat SS and locking the lever in its towing position, the on-off valve V is locked in its closing position Va. You can keep.

  Next, the operation of the casting ship SS will be described. At the time of the casting operation, first, the transfer pipe 12 is tilted by the actuator 16 to the use position underwater according to the water depth, and the outlet 12o is made to approach the bottom of the water. Then, the improved soil S (a mixture obtained by stirring and mixing the cement slurry with the dredged soil and sand, that is, a landfill material) is wind-transported to the casting boat SS via the discharge pipe 6 by the processing boat SW. At this time, the improved soil S receives a high pulsating wind pressure and is intermittently conveyed into the cyclone 3 as a pulsating flow. After the air is separated in the cyclone 3, the surge tank is separated from the cyclone body 3 b by its own weight. It falls into 10 and is temporarily stored there.

  Then, the storage-improved soil S in the surge tank 10 gradually flows into the transfer pipe 12 by its own weight, and is buried in the water bottom E of the disposal site Gr substantially continuously from the lower end outlet 12o of the transfer pipe 12 by a substantially constant amount. Is done.

  By the way, in such an improved soil casting process, when the transfer pipe 12 is submerged in the water and there is no or a small amount of the improved soil S in the pipe, the on-off valve V near the outlet 12o of the pipe 12 is provided. Is held at the closed position Va by the valve closing force based on the water pressure applied thereto and the buoyancy of the float F to prevent backflow of water into the pipe, so that water does not accumulate in the pipe. From this state, the casting process starts, and a large amount of the improved soil S is supplied to the upstream portion of the transfer pipe 12 from the casting boat SS, and when the soil flows down to the vicinity of the outlet 12o, the weight is transferred to the on-off valve V. On the other hand, a valve opening force is exerted, and the valve opening force gradually increases as the supply amount of the improved soil increases. Then, when the valve opening force based on the weight of the improved soil S exceeds the limit value, the on-off valve V opens, and the improved soil is gradually discharged from the transfer pipe outlet 12o. Even after the valve is opened, an appropriate valve closing force acts on the on-off valve V based on the buoyancy of the float F. Therefore, the improved soil is discharged from the transfer pipe outlet 12o by an appropriate amount and is poured into the water bottom E. The backflow of water into the transfer pipe 12 hardly occurs.

  During such a casting process, the supply speed of the improved soil from the casting ship SS into the transfer pipe 12 becomes extremely slow, or the supply of the improved soil is intermittently performed so that the supply is temporarily stopped. May be interrupted. In such a case, the improved soil supply from the casting vessel SS cannot catch up with the improved soil outflow from the transfer pipe outlet 12o, and the remaining amount of the improved soil in the transfer pipe 12 gradually decreases. When the remaining amount decreases to a predetermined limit amount (for example, a remaining amount of about 1 to 2 m upstream from the outlet 12o in the illustrated example), the on-off valve V closes again based on the buoyancy of the float F, and the transfer pipe 12 Is shut off at the outlet 12o.

  In such a closed state of the on-off valve V, some improved soil remains in the vicinity of the outlet 12o of the transfer pipe 12 (for example, in a range of about 1 to 2 m upstream from the outlet 12o). The residual flow and the valve closing action of the on-off valve V combine to effectively prevent the backflow of water into the transfer pipe 12.

  Thus, during the casting process and during standby, a large amount of water does not flow backward from the outlet 12o into the transfer pipe 12, so that the water flows down the transfer pipe 12 from above the casting vessel SS to reach the water bottom. The improved soil S heading toward the pipe has almost no risk of mixing with water in the pipe before it reaches the pipe outlet 12o, so that the soil in the improved soil S becomes solidified and the like in the transfer pipe 12. Since the separation can be effectively suppressed, the improved soil S in a proper state in which the soil is not separated (that is, the soil and the solidified material are sufficiently mixed) is poured into the water bottom E from the pipe outlet 12o. It becomes possible. Therefore, the improved soil S that has been cast can be quickly and firmly solidified on the water bottom E, and the liberation of the solidified material from the soil is suppressed to a minimum, so that the casting due to the diffusion of the solidified material is performed. It is also effective in preventing pollution of the water around the disposal site.

  When the casting process operation is completed, the transfer pipe 12 is swung upward to lift the water above the water surface. At this time, the operating mechanism (not shown) on the casting boat SS is held at the towing position to activate the holding mechanism H. By doing so, the on-off valve V can be reliably locked at the closed position Va. Accordingly, even if the buoyancy (and thus the valve closing force) of the float F disappears or greatly decreases due to the transfer pipe 12 rising to or near the water surface, the on-off valve V does not open unnecessarily. Further, even when the transfer pipe 12 is swung downward from the raised state and is submerged in water, the opening / closing valve V is securely locked at the closed position Va by operating the holding mechanism H as described above. Can be. In the case where the transfer pipe 12 is moved up and down near or on the water surface where the buoyancy of the float F is not sufficient, the holding mechanism H is operated and the on-off valve V is securely locked. In addition, backflow of water into the transfer pipe 12 and discharge of the improved soil from the pipe outlet 12o can be reliably prevented.

  In this embodiment, since the on-off valve V and the float F can be handled as a single part by integrating them, the structure of the apparatus can be simplified, and the assembling workability and maintenance work of the apparatus can be achieved. The property becomes good.

  FIG. 5 shows a second embodiment of the present invention. In the previous embodiment, the on-off valve V and the float F were integrated, but in the second embodiment, the on-off valve V and the float F were made separate from each other so as to be able to approach and separate from each other. The connection is made by a flexible cable 40.

  FIG. 6 shows a third embodiment of the present invention. In the above embodiment, the float F is used as the urging means for urging the on-off valve V in the valve closing direction. In the third embodiment, however, the float F is interposed between the on-off valve V and the transfer pipe 12. The spring Sp is used as an urging means. The spring Sp is disposed at least on one side of the outlet 12o so as not to hinder the flow of the improved soil from the transfer pipe outlet 12o. One end of the spring Sp is at least at the left and right of the on-off valve V. One side and the other end are connected to at least one of the left and right outer walls of the transfer tube 12.

  In this embodiment, basically, the same operation and effect as those of the previous embodiment are achieved, and the biasing force of the spring Sp is used. There is an advantage that can be given to V.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various embodiments are possible within the scope of the present invention. For example, in the above embodiment, the casting vessel SS may be a self-propelled vessel or a non-self-propelled vessel.

  Further, in the above embodiment, the on-off valve V is made as thin and light as possible so that the moment in the valve opening direction or the valve closing direction acting on the pivot P based on the weight and buoyancy of the valve V itself can be ignored. However, if the moment is of a magnitude that cannot be ignored, the desired opening force, closing The urging force of the urging means (float F, spring Sp) is set so that the valve force acts.

  In the above-described embodiment, the pivot P of the on-off valve V is disposed above the transfer pipe outlet 12o. However, the pivot P may be disposed on one side of the transfer pipe outlet 12o or on the lower side. Good.

  Further, in the above embodiment, the transfer pipe 12 is forcibly swung by the hydraulic cylinder 16, but other drive means (for example, a winch) may be employed as the drive means instead of the hydraulic cylinder.

  Further, in the above embodiment, the bottom outlet 10o of the surge tank 10 and the inside of the transfer pipe 12 are always communicated irrespective of the swing angle of the pipe 12 around the pivot 15, so that the space between them can be telescopically expanded and contracted. Although the connection is made via the connection tube portion 14, instead of such a structure, the connection tube portion 14 is formed in a bellows shape so that the connection tube portion 14 can expand and contract while deforming according to the swing of the transfer pipe 12. It may be.

  In the above embodiment, the improved soil S in the surge tank 10 is replenished and transferred to the upstream side of the transfer pipe 12 only by its own weight. However, in the present invention, an auger having screw blades and other forced replenishing devices are used. Alternatively, the improved soil S may be forcibly sent to the upstream side of the transfer pipe 12.

  Further, in the above embodiment, the holding mechanism H capable of locking the on-off valve V at the closed position is provided with the operating lever with the locking mechanism on the casting boat SS, and the lever and the on-off valve V interlockingly connected to the transfer pipe 12. In the present invention, the holding mechanism H is provided with a lock mechanism provided between the transfer pipe 12 and the on-off valve V and driven by an actuator. And a remote control mechanism for remotely controlling the actuator from the casting boat SS.

Schematic plan view showing an example of an improved soil transfer and casting system 1. Enlarged side view along line 2-2 in FIG. FIG. 2 is an enlarged side view of an essential part of a casting boat using a transfer pipe according to a first embodiment of the present invention (an enlarged view taken along line 3 in FIG. 2). Enlarged view of the tip of the transfer pipe (enlarged view as viewed from arrow 4 in FIG. 3) Longitudinal sectional view showing the tip of the transfer pipe according to the second embodiment. The longitudinal section showing the tip of the transfer pipe according to the third embodiment. Explanatory diagram simply showing the backflow rising mechanism of water at the tip of a conventional transfer pipe

Explanation of reference numerals

D ···· Improved soil casting device F ····· Float (biasing means)
H: Lock mechanism Sp: Spring (biasing means)
SS: Casting vessel V: On-off valve 1: Hull 12: Transfer pipe 12o: Exit

Claims (2)

The viscous fluidity-improved soil (S) obtained by adding the kneading material to the soil and sand is stored in a surge tank (10) on a casting vessel (SS), and the fluidity is improved from the bottom of the surge tank (10). The improved soil (S) gradually flows under its own weight into the upper part of the transfer pipe (12) whose lower end extends to the water bottom (E), and flows through the transfer pipe (12) under its own weight to descend. An improved soil casting method in which S) can be continuously poured from the outlet (12o) at the lower end of the transfer pipe (12) to the water bottom (E),
Wherein the transfer tube (12), Rutotomoni mounted an outlet on-off valve capable of opening and closing the (12o) (V) of the tube (12), to the on-off valve (V), this in a closed position (Va) The urging means (F, Sp) for applying the urging force in the valve closing direction for holding to the valve (V) is connected in advance,
At the time of placing the fluidity- improved soil (S), the weight of the fluidity- improved soil (S) gradually flowing by its own weight into the transfer pipe (12) from the bottom of the surge tank (10) is determined by the on-off valve By opening the on-off valve (V) against the urging force of the urging means (F, Sp) by the valve opening force exerted on (V) , the water flows back into the transfer pipe (12). So that the fluidity-improved soil (S) is continuously discharged from the outlet (12o) of the transfer pipe (12),
If the supply of the fluidity-improved soil (S) from the surge tank (10) to the transfer pipe (12) cannot keep up, the fluidity-improved soil (S) remaining in the transfer pipe (12) is reduced to a predetermined amount. As the valve opening force based on the weight of the improved soil (S) decreases to the limit amount and the valve opening force decreases based on the urging force, the on-off valve (V) closes again by the urging force and the outlet (12o). ) it is characterized in that so as to prevent backflow of water into the transfer tube (12) from the modified soil strokes set method. Wherein the opening and closing valve (V) is located close it holding mechanism capable of locking at any time in (Va) (H) is characterized in that it is connected, improved soil strokes set method according to claim 1.