JP5393201B2 - 浚 渫 Method - Google Patents

Description

The present invention relates to a dredging method . More specifically, when dredging dredging is performed, the suction port is prevented from being clogged, and the followability of the suction port to the surface of the sand is improved and the mud content is high. It relates to the method of dredging that enables dredging .

  Conventionally, various dredging methods and apparatuses for lifting sediments such as rivers and lakes from the bottom to the water have been proposed. Dredging work is generally carried out by installing large dredging facilities on land around the large working boat or dredged water area, and using the dredging pump itself and the suction port of the transport pipe connected to the dredging pump, It is done by moving it.

  However, it was difficult to use a large ship or install a large device in a narrow site where a large space such as a dam lake could not be secured. In dredging at a dam lake, etc., a predetermined amount of earth and sand may be dredged in order to increase the amount of water stored, and the finished state of the bottom after dredging is not a problem. Therefore, rather than a method of performing dredging while moving the suction port at the bottom of the water, a so-called dredging kite in which dredging is performed by moving the suction port downward at a fixed position is suitable. Compared with the dredging that moves the suction port at the bottom of the water, the dredging dredging is not necessary to move the suction port in a wide range, so the moving means can be downsized and the entire device can be downsized. is there.

  As a device that can perform dredging without using a large-scale facility, connect a tow rope to an aspirator placed at the bottom of the water, and pull the tow rope from the ground to place the aspirator at any position on the bottom of the water. There has been proposed an apparatus for moving the device (for example, see Patent Document 1). However, in this proposed dredging device, the bottom surface of the suction unit has a flat shape, so that the suction port follows the surface of the sand and sand when the surface of the water and sand is uneven. There was a problem that it was too far away and the water was sucked in excessively, so that the mud with a high mud content could not be formed.

  In addition, when dredging is performed with this dredging device, the side surface of the suction device stands perpendicular to the bottom surface of the suction device, so if the suction device is buried in the earth to some extent, the suction port is closed and suction is performed. There was a problem of becoming impossible.

JP-A-1-295926

The object of the present invention is to improve the ability of the suction port to follow the surface of the bottom of the sand and prevent dredging with a high mud content while preventing clogging of the suction port when performing dredging dredging. It is to provide a method .

In order to achieve the above object, the dredging method of the present invention comprises connecting a transport pipe provided with suction means to a suction head having a bottom surface of a casing having a shape in which a central portion protrudes downward. It is suspended from the floating body via a wire that is fed and wound, and the vertical position of the suction head is adjusted by driving the winch, while the bottom of the water is removed from a porous suction port provided at the center of the bottom surface of the casing. When sucking fluid containing earth and sand to perform dredging dredging, the flow velocity of the fluid containing earth and sand sucked from the suction port is measured by the flow velocity measuring means, and the ground pressure of the suction head is measured by the ground pressure measuring means. The relationship between the contact pressure and the amount of dredged soil and the critical flow velocity of the dredged sediment is known in advance, and the relationship between the detected ground pressure and the amount of dredged soil By adjusting the upper and lower positions of the suction head based on the measurement data obtained by the flow velocity measuring means and the contact pressure measurement means, the flow velocity in the transport pipe is set to be equal to or higher than the critical flow velocity and the amount of dredged sand is adjusted. It is characterized by performing a trap .

Here, as the ground pressure measuring means, for example, using a tensiometer that measures the tension of the wire and a control device to which the measurement data by the tensiometer is input, the measurement based on the measurement data by the tensiometer is used. The ground pressure can also be measured.

According to the present invention, when carrying out dredging by hanging the suction head from a floating body via a wire that is fed and wound by a winch, the central portion of the bottom surface of the casing is projected downward. By providing a porous suction port in the center of this bottom surface, even if the bottom sediment surface has an undulating shape, the casing tilts so that it corresponds to the bottom sediment surface. The mouth can be placed adjacent to the bottom sediment surface. Thereby, a high mud content can be secured. And by using a porous suction port, since suction is performed through a large number of holes, it is possible to prevent the suction port from being blocked.

  In addition, by adjusting the vertical position of the suction head by driving the winch, the ground pressure can be made appropriate, the mud content can be improved, and the amount of dredged sand can be maximized.

It is explanatory drawing which illustrates the state which is implementing the dredging method of this invention. It is a front view illustrating a suction head of FIG. It is explanatory drawing which illustrates the inside of the suction head of FIG. 2 with a longitudinal cross-section. FIG. 3 is a bottom view of the suction head of FIG. 2. It is explanatory drawing which illustrates the state which moved the suction head of FIG. 3 downward until the upper surface of the casing was buried in earth and sand. It is a front view which illustrates another embodiment of a suction head used for the present invention. It is a graph which illustrates the relationship between the ground pressure of a suction head and the flow velocity in a transport pipe. It is a graph which illustrates the relationship between the contact pressure of a suction head, and the amount of dredged soil.

The scissors method of the present invention will be described based on the embodiments shown in the drawings.

As illustrated in FIGS. 1 to 4, the suction head 1 used in the present invention is connected to one end side of a transport pipe 6 provided with suction means 7, and the other end side of the transport pipe 6 is connected to a sediment disposal site or the like. It is extended so that it may arrange. The suction head 1 is connected to a wire 9 that is fed and wound by a winch 10 installed on the floating body 8. Thereby, the suction head 1 is suspended from the floating body 8 via the wire 9.

  The floating body 8 is provided with a control device 13, a tension meter 11 that measures the tension of the wire 9, and a depth meter 12 that measures the water depth of the suction head 1. The transport pipe 6 is provided with flow velocity measuring means 14 for measuring the flow speed inside the transport pipe 6. The control device 13 is connected to a drive source (drive motor or the like) of the winch 10, a tension meter 11, a water depth meter 12, and a flow velocity measuring means 14 by wire or wirelessly. The control device 13 is not limited to the floating body 8 and can be disposed on land, for example.

  In this embodiment, the tension meter 11 and the control device 13 function as a ground pressure measuring unit that measures the ground pressure of the suction head 1. As the ground pressure measuring means, for example, a pressure sensor can be used. When the pressure sensor is attached to the bottom surface of the suction head 1, the ground pressure of the suction head 1 is directly measured.

  The casing 2 of the suction head 1 is composed of a hemispherical upper casing 2a and a lower casing 2b, and is spherical by joining together. The outer diameter of the casing 2 is, for example, about 1 m to 4 m with a center of about 1.5 m, but is not limited to this range.

  Although the upper casing 2a and the lower casing 2b are joined to each other by flanges, they can be joined to provide a smooth surface without providing the flanges. The shape of the bottom surface of the casing 2 (lower casing 2b) may be any shape as long as the central portion in plan view protrudes downward, and is not limited to a spherical shape, but may be, for example, a polygonal pyramid, but protrudes downward as much as possible. The curved shape is good.

  The shape of the upper surface of the casing 2 (upper casing 2a) is not particularly limited, and may be a flat shape. However, it is preferable that the central portion in a plan view protrudes upward as in this embodiment. For example, the shape of the upper surface of the casing 2 can be a polygonal pyramid that protrudes upward, but a curved surface that protrudes upward as much as possible is preferable.

  A suction port 3 is provided in the center of the bottom surface of the casing 2 in plan view. The suction port 3 has a porous shape having a large number of through holes 3a. The size of the through hole 3a is, for example, about 10 mm to 50 mm corresponding to the diameter. Although all the through holes 3a can be the same size, it is also possible to mix through holes 3a having different sizes. Although the number of the through-holes 3a is determined suitably, it is about 5-100 pieces, for example.

  A plurality of grooves 4 extending upward from the suction port 3 are formed on the outer surface of the casing 2. As illustrated in FIG. 4, the plurality of grooves 4 are arranged radially at equal central angles with the suction port 3 as the center in a plan view (bottom view) of the suction head 1 (casing 2). Although providing the groove 4 is optional, the groove 4 enables smooth wrinkling as will be described later.

  The groove 4 is preferably extended to the vicinity of the center in the height direction of the casing 2 or to a position where the casing 2 has the maximum outer diameter, and can be extended to the upper surface of the casing 2. The grooves 4 may extend non-linearly in a plan view (bottom view). For example, a plurality of arc-shaped grooves 4 may be arranged at equal central angles with the suction port 3 as the center. it can.

  The number of the grooves 4 is not particularly limited, but is, for example, about 3 to 24, and is preferably arranged at a uniform central angle with the suction port 3 as the center. The depth and width of the grooves 4 are, for example, 10 mm. About 50 mm.

  As the suction means 7, a sand pump or a water jet pump can be used. In this embodiment, the suction means 7 is installed inside the suction head 1, but the installation position is not limited to this, and the transport pipe 6 is installed outside the suction head 1, for example, on the floating body 8 or on land. You may make it attach to.

  Since the floating body 8 only needs to have a buoyancy in which the winch 10 or the like is mounted and the suction head 1 can be suspended via the wire 9, for example, a small boat or the like can be used. The flow velocity measuring means 14 only needs to be able to measure the flow velocity of the fluid flowing inside the transport pipe 6, and for example, an electromagnetic flow meter, an electromagnetic flow meter, an ultrasonic flow meter, or the like can be used. Since the flow meter calculates the flow rate by multiplying the measured flow rate by the cross-sectional area of the transport pipe 6, it can be used to grasp the flow rate.

  The control device 13 receives the measurement data of the tension of the wire 9 by the tensiometer 11, the measurement data of the depth of the suction head 1 by the depth meter 12, and the measurement data of the flow velocity inside the transport pipe 6 by the flow velocity measuring means 14. It is configured as follows. The relationship between the tension of the wire 9 and the ground pressure of the suction head 1 is also input to the control device 13. Thereby, the ground pressure of the suction head 1 can be grasped by obtaining the measurement data of the tension by the tensiometer 11. As the tension of the wire 9 decreases, the ground pressure of the suction head 1 tends to increase.

  The control device 13 controls driving of the winch 10 (operation and stop, rotation speed, rotation direction). Therefore, the vertical movement of the suction head 1 is controlled by the control device 13, and thereby the ground pressure with respect to the earth and sand G at the bottom of the suction head 1 is adjusted.

In addition to the simple spherical shape illustrated in FIG. 2, this suction head 1 is illustrated as an elliptical sphere having a cylindrical portion between the bottom surface and the top surface of the casing 2 as illustrated in FIG. can do. Although the lower casing 2b can be formed in a polygonal pyramid shape or the like so that the center portion of the bottom surface protrudes downward, a curved surface shape protruding downward as much as possible is preferable.

  Furthermore, the suction head 1 illustrated in FIG. 6 is provided on the outer surface of the casing 2 in place of the groove 4 illustrated in FIG. 2, and extends in the vicinity of the suction port 3 from the intermediate portion in the vertical direction along the outer surface. A water supply pipe 5 is provided. The moisture supply pipe 5 is connected to a moisture supply pump installed inside the casing 2. Then, the water W supplied from the water supply pump is supplied to the outer surface of the casing 2 around the suction port 3 through the water supply pipe 5. As described above, it is optional to provide the moisture supply means including the moisture supply pipe 5 and the moisture supply pump. However, as will be described later, the moisture supply means enables smooth dredging.

  The position of the lower end portion of the water supply pipe 5 serving as a discharge port for the supplied water W is evenly centered on the suction port 3 in plan view (bottom view) of the suction head 1 (casing 2) illustrated in FIG. It is preferable that the central angle be arranged. The number of moisture supply pipes 5 is not particularly limited, but is, for example, about 3 to 24.

Other configurations are the same as those of the suction head 1 illustrated in FIG. The suction head 1 used in the present invention can be provided with both the groove 4 and the water supply means (water supply pipe 5). In that case, for example, the grooves 4 and the water supply pipes 5 are alternately arranged in the circumferential direction of the casing 2.

  When performing dredging by the dredging method of the present invention, the vertical position of the suction head 1 is adjusted by driving the winch 10 and the porous suction port 3 provided at the center of the bottom surface of the casing 2 is used. A fluid containing earth and sand G at the bottom of the water is sucked.

  When the central part of the bottom surface of the casing 2 protrudes downward and the suction port 3 having a large number of through holes 3a is provided in the central part of the bottom surface, the earth and sand surface of the bottom of the water has a undulating shape. Even so, the casing 2 can be tilted so as to correspond to the sediment surface of the bottom of the water, and the suction port 3 can be made to follow and adjoin the sediment surface of the bottom of the water. Therefore, a high mud content can be ensured without sucking useless moisture.

  Since the suction port 3 is made porous, even if the earth and sand G are clogged in a certain through hole 3a, the earth and sand G are sucked through the other through holes 3a. Since the clogging of the clogged through hole 3a is easily eliminated by the flow of the suction through the other through hole 3a, etc., the clogging of the suction port 3 can be prevented.

  When the bottom sediment G is sucked from the suction port 3, moderate moisture is required, and when the entire range of the suction port 3 is simultaneously closed by the soil G, suction becomes difficult. Even in such a case, since the suction head 1 illustrated in FIG. 2 has the groove 4 on the outer surface of the casing 2, moisture is supplied to the vicinity of the suction port 3 through the groove 4. Therefore, stable suction can be ensured.

  Further, since the suction head 1 illustrated in FIG. 6 has the moisture supply means, the moisture W can be actively supplied to the vicinity of the suction port 3 through the moisture supply pipe 5. Therefore, stable suction can be ensured.

  As illustrated in FIG. 5, in the case where the suction head 1 is moved downward until the upper surface of the casing 2 is buried in the earth and sand G to perform the dredging dredging, the upper surface of the suction head 1 is caused by the earth and sand G that has collapsed. Covered. In such a case, when the wire 9 is wound around the winch 10 and the suction head 1 is moved upward, the earth and sand G covering the upper surface of the casing 2 becomes a large resistance. However, since the suction head 1 has a shape in which the central portion of the upper surface of the casing 2 protrudes upward, as the suction head 1 moves upward, the earth and sand G covering the upper surface becomes the surface of the casing 2. Move along and be shaken off. Therefore, it is possible to move the suction head 1 upward without causing a large resistance.

  After performing the dredging in one position, the floating body 8 (suction head 1) is moved horizontally to similarly perform the dredging in another position. Thus, the same operation is repeated until the target predetermined amount of earth and sand G is dredged. In general dredging, the finishing condition such as flatness is required for the bottom sediment surface after dredging. However, in dredging such as dam lakes, there is no requirement for the finished state of the bottom of the water. Therefore, this kind of dredging can be applied.

  For example, the vertical position of the suction head 1 is adjusted as follows.

  First, a preliminary survey is performed on the sediment G on the bottom of the dredging object, and the critical flow velocity VM is grasped in advance. The critical flow velocity VM is a minimum flow velocity at which the fluid containing the earth and sand G can be sent without being settled inside the transport pipe 6. That is, if the flow velocity V of the sucked earth and sand G is not equal to or higher than the limit flow speed VM, the inside of the transport pipe 6 is blocked by the earth and sand G. Therefore, data of the critical flow velocity VM of the earth and sand G grasped in advance is input to the control device 13.

  When the fluid containing the sucked earth and sand G flows through the inside of the transport pipe 6, if the ratio of the sand and sand G in the fluid increases (the mud content increases), the flow velocity V inside the transport pipe 6 becomes slow, When the ratio of earth and sand G in the fluid decreases (the mud content decreases), the flow velocity V inside the transport pipe 6 tends to increase. As shown in FIG. 7, the relationship between the ground pressure P of the suction head 1 and the flow velocity V inside the transport pipe 6 tends to decrease as the ground pressure P increases. If P is excessive, suction cannot be performed and the flow velocity V becomes zero. In other words, the flow velocity V tends to decrease as the tension of the wire 9 measured by the tension meter 11 decreases.

  In FIG. 7, since the ground pressure P at which the critical flow velocity VM is reached is PM, the ground pressure P is set to be equal to or lower than PM in order to make the flow velocity V equal to or higher than the critical flow velocity VM. In this way, by adjusting the vertical position of the suction head 1 and changing the ground pressure P (mud content), the flow velocity V inside the transport pipe 6 is set to be equal to or higher than the limit flow velocity VM.

  Since the flow rate Q of the transport pipe 6 is obtained by multiplying the flow velocity V by the cross-sectional area of the transport tube 6, replacing the critical flow velocity VM with the critical flow rate QM and making the flow rate Q equal to or higher than the critical flow rate QM Is the same as the critical flow velocity VM or more.

  In addition, a preliminary survey is performed on the sediment G on the bottom of the dredging object, and the relationship between the contact pressure P of the suction head 1 and the dredged soil amount S is grasped in advance. The dredged soil amount S is the amount of soil (excluding moisture) per unit time sucked from the suction head 1 and dredged. Data regarding the relationship between the ground pressure P of the suction head 1 and the amount of dredged sand S that has been grasped in advance is input to the control device 13.

  As illustrated in FIG. 8, the relationship between the contact pressure P and the dredged sand amount S has a tendency that the dredged sand amount S reaches a peak (maximum amount SX) at a specific contact pressure PX (hereinafter referred to as a specific contact pressure PX). There is. Therefore, by adjusting the ground pressure P of the suction head 1 to the specific ground pressure PX (approaching it), efficient dredging can be performed.

  Next, the suction head 1 suspended from the floating body 8 via the wire 9 is driven by driving the winch 10 to move the wire 9 downward and the suction head 1 is suspended (the wire 9 is tensioned). ) To make contact with the surface of the bottom sediment. In this state, the fluid including the earth and sand G is sucked from the suction port 3 (many through holes 3a) by the suction force of the suction means 7.

  At this time, based on the measurement data of the flow velocity V of the fluid including the earth and sand G by the flow velocity measuring means 14, the drive of the winch 10 is controlled to adjust the vertical position of the suction head 1 so that the flow velocity V becomes equal to or higher than the limit flow velocity VM. To do. Thereby, stable suction can be performed without closing the inside of the transport pipe 6 with the earth and sand G.

  Further, the vertical position of the suction head 1 is adjusted by controlling the drive of the winch 10 based on the tension measurement data obtained by the tensiometer 11, so that the dredged sand amount S becomes the maximum amount SX. . Specifically, dredging is performed so that the obtained dredged sand amount S falls within a set range.

  For example, the contact pressure P of the suction head 1 calculated based on the measurement data of the tension of the wire 9 by the tension meter 11 is 0.9 times the contact pressure PX that is the maximum amount SX grasped in advance shown in FIG. The vertical position of the suction head 1 is adjusted so that the range is 1.1 times. Thereby, the dredged sand amount S close to the maximum amount SX can be obtained. Alternatively, the contact pressure P of the suction head 1 calculated based on the measurement data of the tension of the wire 9 by the tensiometer 11 is the contact pressure P at which 80% or more of the maximum amount SX grasped in advance shown in FIG. Thus, the vertical position of the suction head 1 is adjusted. Since the shape (peak shape) of the curve indicating the relationship between the contact pressure P and the amount of dredged soil S differs depending on the properties of the dredged soil G, the amount of dredged soil S to be obtained depends on the properties of the sediment G. A predetermined range is set.

  By sucking the bottom sediment G, the position of the bottom sediment surface facing the suction port 3 moves downward. Based on the measurement data of the flow velocity V by the flow velocity measuring means 14 and the measurement data of the tension by the tensiometer 11. The vertical movement of the suction head 1 is sequentially controlled so that the flow velocity V is equal to or higher than the limit flow velocity VM and the dredged sand amount S is maximized (predetermined range).

  As described above, the fluid flow velocity V is equal to or higher than the limit flow velocity VM, and the ground pressure P of the suction head 1 calculated based on the measurement data obtained by the tensiometer 11 is brought closer to the specific ground pressure PX, thereby transporting the fluid. The dredged sand amount S can be maximized within a range in which the inside of the pipe 6 is not clogged with the dredged soil G.

  The depth of the suction head 1 to be moved up and down can be confirmed by the depth meter 12. When the suction cannot be performed, or when the depth measured by the depth meter 12 reaches the set depth, the wrinkle at that position is terminated.

  The vertical position of the suction head 1 can be adjusted not only by controlling the driving of the winch 10 by the control device 13 but also by controlling the driving of the winch 10 by an operator manually. At this time, the ground pressure P of the suction head 1 and the flow velocity V inside the transport pipe 6 are displayed on the monitor in real time, and information on the critical flow velocity VM and information on the relationship between the ground pressure P and the amount of dredged sand S are monitored. To display. The operator looks at the display on the monitor and operates the drive of the winch 10 so that the ground pressure P approaches the specific ground pressure PX.

  As described above, the present invention performs dredging as described above, so that a large-scale mechanism and device for horizontally moving the suction head 1 are not required, and the size can be reduced. Therefore, necessary equipment can be transported by, for example, a helicopter and can be easily applied to a site such as a dam lake.

DESCRIPTION OF SYMBOLS 1 Suction head 2 Casing 2a Upper casing 2b Lower casing 3 Suction port 3a Through-hole 4 Groove 5 Moisture supply pipe 6 Transport pipe 7 Suction means 8 Floating body 9 Wire 10 Winch 11 Tensiometer 12 Depth meter 13 Controller 14 Flow velocity measuring means G Sediment

Claims (2)

Connect the transport pipe with suction means to the suction head with the bottom part of the casing projecting downward in the center, and connect this suction head to the floating body via the wire that is fed and wound by the winch While hanging and adjusting the vertical position of the suction head by driving the winch, the fluid containing sediment at the bottom of the water is sucked from the porous suction port provided at the center of the bottom surface of the casing, and the dredger is dug In performing , the flow velocity of the fluid containing the earth and sand sucked from the suction port is measured by the flow velocity measuring means, and the ground pressure of the suction head is measured by the ground pressure measuring means, The relationship between the amount of dredged sediment and the critical flow velocity is known in advance, the relationship between the ground pressure and the amount of dredged soil and the critical flow velocity, the flow velocity measuring means and Dredging method by adjusting the vertical position of the suction head on the basis of the measured data by the pressure measuring means performs dredging the flow rate of the transport tube by adjusting the dredged material amount with which the above critical velocity. The ground pressure is measured based on the measurement data obtained by the tensiometer using a tensiometer that measures the tension of the wire and a control device to which the measurement data obtained by the tensiometer is input as the ground pressure measurement means. The dredge method according to claim 1 .

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