JP6503951B2 - Method and system for preventing withdrawal of suction anchor - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method and system for preventing withdrawal of a suction anchor that is mainly set in a seabed or the like.

  In order to hold the floating marine structure at a predetermined position on the sea, the anchor is anchored to the seabed anchor via a mooring cord or chain composed of wires or chains, or anchored via a tensor called tendon. Suction anchors are known as such anchors.

  The suction anchor utilizes a suction structure composed of a cylindrical peripheral wall and a top plate closing one end as an anchor, and the opening side of the cylindrical peripheral wall is on the lower side at the time of sinking As described above, after the suction structure is installed on the seabed, the water in the cylindrical peripheral wall is drained to generate a water pressure difference between the inside and the outside, and the cylindrical peripheral wall is penetrated into the seabed ground using the water pressure difference as a pushing force. It can be constructed without using a special construction machine, as long as it can carry out, and there is only a hoisting vessel for installing a suction structure and a drainage pump for giving a suction force, and it can be constructed without using a special construction machine. To the force, passive earth pressure from the seabed ground acting on the outer peripheral surface of the cylindrical peripheral wall is a resistance force, so the drilling period can be shortened and as an anchor method with excellent strength characteristics, oil drilling in the North Sea oil field The It has been adopted by such Ttohomu.

  On the other hand, with the urgent need to secure new energy sources that can control greenhouse gas emissions and have excellent safety, offshore wind power generation is considered promising in Japan, but the installation method is as follows: Because the water depth in the surrounding sea area is relatively large, the introduction of a floating type using a suction anchor is being considered.

JP, 2015-34430, A

  When an external force such as waves or strong winds acts on a floating offshore structure such as offshore wind power generation, tensile force is transmitted to the suction anchor via a tension cord etc. However, the weight of the suction anchor and its surrounding surface The load combined with the circumferential friction force from the seabed ground acting on the surface acts as a resistance, and the resistance supports the above-mentioned tensile force.

  Therefore, when the tensile force due to the external force is equal to or less than the above-described resistance, the soundness of the suction anchor relating to the withdrawal is reliably maintained.

  On the other hand, when an excessive external force acts on the offshore structure and the tensile force exceeds the above-mentioned resistance, a phenomenon occurs in which the suction anchor is pulled out of the seabed ground.

  At that time, a water pressure difference occurs inside and outside the suction anchor according to the size of the drawing displacement, and the water pressure difference pushes the suction anchor downward and resists drawing, but the drawing displacement is an excessive external force As it becomes larger each time it is accumulated, in the suction anchor, the resistance due to the circumferential surface frictional force gradually decreases, and eventually the function as the anchor is lost.

  Incidentally, increasing the size of the suction anchor solves the above-mentioned problems, but in that case there is a concern that the economic efficiency will be lost.

  The present invention has been made in consideration of the above-described circumstances, and it is an object of the present invention to provide a method and system for preventing withdrawal of a suction anchor capable of preventing withdrawal due to excessive external force without increasing the size of the suction anchor. Do.

In order to achieve the above object, the method for preventing withdrawal of a suction anchor according to the present invention comprises, as described in claim 1, a cylindrical peripheral wall portion and a top plate portion closing one end thereof. In the method for preventing withdrawal of the suction anchor which is inserted into the
Measure the tensile force of the tensile material connecting the suction anchor and the floating structure,
The water in the suction anchor is drained when the tensile force exceeds or is likely to exceed a predetermined allowable tensile force.

Further, as described in claim 2, the method for preventing withdrawal of the suction anchor according to the present invention comprises a cylindrical peripheral wall portion and a top plate portion closing one end thereof, and the cylindrical peripheral wall portion is penetrated into the underwater ground. In the method of preventing withdrawal of suction anchor,
Waves around the floating structure, which are connected to the suction anchor via tension members, tide fluctuations, wind power and other meteorological elements, or posture changes of the floating structure, or when the floating structure is a wind power generation facility Measure the amount of power generation,
The tensile force of the tensile material is estimated using the result obtained in the measurement step,
The water in the suction anchor is drained when the tensile force exceeds or is likely to exceed a predetermined allowable tensile force.

Further, as described in claim 3, the suction anchor pullout preventing system according to the present invention is constituted by a cylindrical peripheral wall portion and a top plate portion closing one end of the cylindrical peripheral wall portion, and the cylindrical peripheral wall portion is penetrated into the underwater ground. In a withdrawal prevention system for a suction anchor connected to a floating body structure via a tension member at
It comprises: a drainage pump communicatively connected to the internal space of the suction anchor; measurement means for measuring the tensile force generated in the tension member; and arithmetic control means for controlling the operation of the drainage pump, the arithmetic control means Determining whether the tensile force measured by the measuring means exceeds or exceeds a predetermined allowable tensile force, and the tensile force may exceed or exceed the allowable tensile force; The pump is to be operated.

The suction anchor pullout preventing system according to the present invention comprises the cylindrical peripheral wall portion and the top plate portion closing one end as described in claim 4, and the cylindrical peripheral wall portion is penetrated into the underwater ground. In a withdrawal prevention system for a suction anchor connected to a floating body structure via a tension member at
The drainage pump connected to the internal space of the suction anchor, waves around the floating structure, tide fluctuation, wind power and other meteorological elements or posture changes of the floating structure are measured or the floating structure is a wind power generator In the case of a facility, it comprises measurement means for measuring the amount of power generation, and arithmetic control means for controlling the operation of the drainage pump, wherein the arithmetic control means pulls the tension material using the measurement result by the measurement means. The force is estimated, it is determined whether or not the tensile force exceeds or exceeds a predetermined allowable tensile force, and when the tensile force is likely to exceed or exceed the allowable tensile force, the drainage pump is It is intended to be activated.

  Further, in the suction anchor withdrawal prevention system according to the present invention, the pressure difference between the inside and the outside of the suction anchor caused by the operation of the drainage pump increases stepwise or continuously toward the predetermined maximum pressure difference. The arithmetic control means is configured to increase gradually.

[Method for preventing withdrawal of suction anchor]
In the method for preventing withdrawal of a suction anchor according to the first and second inventions, the method is applied to a suction anchor which is constituted by a cylindrical peripheral wall portion and a top plate portion closing one end thereof and the cylindrical peripheral wall portion is penetrated into water bottom ground. In the first invention, the tensile force of the tensile material connecting the suction anchor and the floating structure is measured, and in the second invention, the floating body structure connected to the suction anchor via the tensile material. Waves around the object, tide fluctuations, wind power and other meteorological elements or posture changes of the floating structure are measured, or if the floating structure is a wind power generation facility, the amount of power generation is measured.

  Next, in the case of the second invention, when the tensile force of the tension material is estimated using the result obtained in the measurement step, and the tensile force exceeds or exceeds a predetermined allowable tensile force. Drain the water in the suction anchor.

[Suction anchor withdrawal prevention system]
In the suction anchor withdrawal prevention system according to the third and fourth inventions, it is applied to a suction anchor which is constituted by a cylindrical peripheral wall portion and a top plate portion closing the one end, and the cylindrical peripheral wall portion is penetrated into the underwater ground. In the third invention, the tensile force of the tensile material connecting the suction anchor and the floating structure is measured by the measuring means, and in the fourth invention, the suction anchor is connected to the floating structure via the tensile material. Waves around the floating body structure, tide fluctuation, wind power and other meteorological elements or attitude changes of the floating body structure are measured by the measuring means, or if the floating body structure is a wind power generation facility measure.

  Next, in the case of the fourth invention, the tensile force of the tensile material is estimated by the arithmetic control means using the measurement result by the measuring means, and the measured tensile force or the estimated tensile force is predetermined. It is determined by the arithmetic control means whether or not the allowable tensile force is exceeded.

  Next, when there is a possibility that the tensile force exceeds or exceeds the allowable tensile force, the water in the suction anchor is drained by operating the drainage pump by the arithmetic control means.

[Common to each invention]
In this case, in each of the first to fourth inventions, a water pressure difference is generated inside and outside the suction anchor, and the water pressure difference pushes the suction anchor downward and resists the tensile force, so an increase in tensile force can be obtained. It can support by the pushing force by the water pressure difference mentioned above.

  Therefore, if the allowable tensile force is set appropriately, the frictional force from the bottom of the water acting on the circumferential surface of the suction anchor reaches the limit circumferential frictional force, that is, the frictional force immediately before the suction anchor is pulled out of the underwater bottom. It becomes possible to make it hard, and in this way it is possible to prevent the situation where the suction anchor is pulled out from the water bottom ground by exceeding the resistance which combines the self weight of the suction anchor and its circumferential friction. .

  The waterbed ground includes the seabed ground and the ground spreading to the water bottom such as a lake.

  The floating structure mainly corresponds to TLP type (tension leg platform) offshore wind power facilities, but also includes an oil drilling platform.

[Inventions pertaining to second and fourth]
In the second and fourth inventions,
(a) Waves around the floating structure, tide fluctuation, wind power and other meteorological elements or attitude changes of the floating structure
(b) When the floating body structure is a wind power generation facility, one of the power generation amounts is to be measured, and in the second invention, a worker etc. In the fourth invention, the arithmetic control means respectively estimates, and then, in the second invention, a worker or the like determines whether or not the tensile force exceeds or exceeds the predetermined allowable tensile force. In the fourth invention, the operation control means makes a determination.

  The meteorological factor of (a) means a measurable physical variation characteristic caused by the weather, and includes not only the above-mentioned waves, tide variation, wind power, etc. but also atmospheric pressure, water pressure fluctuation, etc.

  Here, in (a), for example, if the wave height, tide level or wind force in the surrounding water area of the floating body structure and the fluctuation characteristics of the tensile force in the tension member are linked in advance by field surveys or experiments, etc. Alternatively, by measuring the wind force, the tensile force of the tension member can be estimated, and the same applies to the posture change of the floating body structure, for example, the rotational angle around the center of gravity and the fluctuation characteristics of the tensile force in the tension member Can be estimated, by measuring the rotation angle.

  In (b), since the relationship between the amount of power generation and the wind power is grasped in advance as the specification of the wind power generation facility, if the amount of power generation is measured, the tensile force of the tension material can be estimated.

[Inventions pertaining to third and fourth aspects]
In the third aspect of the invention, the allowable tensile force is stored, and in the fourth aspect of the invention, the relationship between the association and the power generation amount and the wind force is stored in the form of data in the arithmetic control means, respectively, The above estimation and determination may be performed.

  Although the manner in which the drainage pump is operated is optional, the pressure difference between the inside and the outside of the suction anchor caused by the operation of the drainage pump is gradually increased or continuously increased toward the predetermined maximum pressure difference. If the calculation control means is configured to perform the pressure difference formation too fast, or if the pressure difference is too large, the effective stress of the water bottom ground is prevented from being sharply reduced, and thus the water bottom ground such as boiling etc. It is possible to prevent the breakage phenomenon of the above and the decrease in pullout resistance of the suction anchor.

  The maximum pressure difference is an upper limit value of the pressure difference between the inside and outside of the suction anchor, and is called so-called limit suction, and can be determined in advance from the failure condition of the underwater ground and the like.

  Among the above-described configurations, as a specific example in the case of stepwise increase, when the maximum pressure difference is 100%, the pressure difference inside and outside the suction anchor increases stepwise, for example, 25%, 50%, 75%. When the pressure difference between the inside and the outside of the suction anchor reaches each of the above-mentioned stages, the operation of the drainage pump is temporarily stopped and resumed after a predetermined time has elapsed, or after being temporarily stopped at each stage It is possible to adopt a configuration in which the situation is confirmed and if there is no problem, the operation of the drainage pump is resumed for the next stage, and if there is a problem, the operation of the drainage pump is stopped.

  On the other hand, in the case of continuous gradual increase, while operating the drainage pump toward the maximum pressure difference, continuously monitor the condition of the underwater ground, and if there is no problem, continue the operation of the drainage pump, and if there is a problem It is possible to adopt a configuration for stopping the operation.

It is a figure of the withdrawal prevention system 1 of the suction anchor which concerns on 1st Embodiment, (a) is a layout, (b) is a block diagram. The detail figure which showed a mode that drawing-out of the suction anchor 2 was prevented using the extraction prevention system 1 of the suction anchor which concerns on 1st Embodiment. Explanatory drawing which showed the effect | action of the withdrawal prevention system 1 of the suction anchor which concerns on 1st Embodiment. It is a figure of the withdrawal prevention system 41 of the suction anchor which concerns on 2nd Embodiment, (a) is a layout, (b) is a block diagram.

  BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the suction anchor extraction prevention method and system according to the present invention will be described below with reference to the attached drawings.

First Embodiment
FIG. 1 is a layout view and a block diagram of a suction anchor withdrawal prevention system 1 according to a first embodiment. As can be seen from these figures, the suction anchor withdrawal prevention system 1 according to the present embodiment is applied to the suction anchor 2 composed of the cylindrical peripheral wall portion 3 and the top plate portion 4 that closes one end thereof. The suction anchor is connected to the wind power generation facility 6 as a floating body structure by connecting the tension cord 5 as a tension material in a state where the cylindrical peripheral wall portion 3 is intruded into the seabed ground 9. Can be moored.

  The wind power generation facility 6 is configured as an offshore wind power generation facility of TLP type (tension leg platform).

  The suction anchor withdrawal prevention system 1 according to the present embodiment includes a drainage pump 10 communicatively connected to the internal space of the suction anchor 2 and a load meter 7 as a measuring means for measuring the tensile force generated in the tension cord 5; An arithmetic control unit 8 as arithmetic control means for controlling the operation of the drainage pump 10 is provided.

  The drainage pump 10 can be configured by, for example, an electric submersible pump, and may be placed on the top plate 4 of the suction anchor 2, and if maintenance and inspection are considered, the wind power generation facility 6 It is possible to attach it to the upper surface of the bottom plate 6a or the side surface of the column 6b erected on the bottom plate, but in any case, by interposing a drainage hose or the like, the internal space of the suction anchor 2, ie, the cylindrical peripheral wall portion It is configured to be communicably connected to the inner space surrounded by 3 and the top plate 4.

  The load meter 7 may be appropriately selected from known measuring means capable of measuring the tension of a wire or a rope, but in consideration of the fact that the measurement environment is underwater, adopting a measurement method by a three-point roll method, for example it can.

  The arithmetic and control unit 8 determines whether the tensile force measured by the load meter 7 exceeds or is likely to exceed a predetermined allowable tensile force, and the tensile force may exceed or exceed the allowable tensile force. At one time, the drainage pump 10 is operated to drain water spreading to the internal space of the suction anchor 2.

  If there is a concern that seawater will flow back through the drainage hose or the like connected to the drainage pump when the drainage pump 10 is not operating, an on-off valve (not shown) should be provided on the drainage hose or the like. In addition, it may be configured to drive and control the operation and control device 8 in a manner to interlock this with the drainage pump 10.

  In order to prevent the withdrawal of the suction anchor 2 using the withdrawal prevention system 1 of the suction anchor according to the present embodiment, first, the tensile force generated in the tension cord 5 is measured by the load meter 7.

  The wind power generation facility 6 translates or swings up and down and to the left and right due to waves, wind, or tide fluctuation, and accordingly the tensile force of the tension cord 5 connecting the wind power generation facility and the suction anchor 2 also fluctuates. By measuring this with the load meter 7, the arithmetic and control unit 8 continuously monitors the tension generated in the tension cord 5.

  The measurement by the load meter 7 may be performed continuously or at arbitrary time intervals, but in the latter case, the measurement interval is made relatively long when the sea is quiet, When the sea is rough, if the construction is made relatively short, it is possible to efficiently monitor the tensile force generated in the tension cord 5.

  Next, the arithmetic and control unit 8 determines whether the tensile force P measured by the load meter 7 exceeds or exceeds a predetermined allowable tensile force.

In the determination, the sum of the weight W of the suction anchor 2 and the limit surface frictional force R _U from the seabed ground 9 acting on the cylindrical peripheral wall portion 3 is the maximum pullout resistance P _U. safety factor to the maximum pull-out resistance force _{P U α (0 <α ≦} 1) and the permissible tensile force .alpha.P _U a value obtained by multiplying, by an arithmetic control unit 8 to determine a magnitude relation between the allowable tensile force Good.

Result of the determination, if the tensile force P which is measured by the load meter 7 falls below the allowable tensile force .alpha.P _U, as shown in FIG. 2 (a), a tensile force P is the self-weight W of the suction anchor 2 that tubular More than the maximum pullout resistance P _U which is balanced with the sum of the circumferential surface frictional force R from the seabed ground 9 acting on the peripheral wall portion 3 and which is also the sum of the self weight W and the limit circumferential surface frictional force R _U Small relationship,
P = W + R
P <W + R _U
Because there is no possibility that the suction anchor 2 will be pulled out of the seabed ground 9, the measurement by the load meter 7 and the monitoring by the arithmetic and control unit 8 are continued.

On the other hand, if the tensile force P exceeds the allowable tensile force αP _U , the suction anchor 2 may be pulled out of the seabed ground 9. In such a case, the drainage pump 10 is operated by the arithmetic and control unit 8. The water in the suction anchor 2 is drained through the drain hose 21 as shown in FIG. 2 (b).

In this way, a water pressure difference is generated inside and outside the suction anchor 2, and the water pressure difference becomes a pushing force ΔS and pushes the suction anchor 4 downward, and the following equation,
P = W + R + ΔS
P <W + R _U + ΔS
As shown in, as well as resistance to the cited tension in the form commensurate with the increase in the [Delta] S is the tensile force P, [Delta] S is applied to the maximum pull-out resistance force P _U (hereinafter, referred to as the maximum pull-out resistance force P _U ', the maximum pull-out resistance force distinguished from P _U) that, suction anchor 2 our it nor withdrawn from the seabed 9.

  As described above, according to the suction anchor withdrawal prevention system 1 and method according to the present embodiment, a water pressure difference is generated between the inside and the outside of the suction anchor 2 by the drainage operation by the drainage pump 10, and the pushing force ΔS due to the water pressure difference Since the suction anchor 2 is pushed downward at the end to resist the tensile force P, even if the tensile force P generated in the tension cord 5 fluctuates in the increasing direction due to waves, wind or tide fluctuation, the increase is described above It can be supported by a pressing force ΔS due to a water pressure difference.

Therefore, safety factor alpha, by setting appropriately and hence acceptable tensile force .alpha.P _U, with respect to an external force of a certain size, the frictional force is limited circumferential surface frictional force from Seabed 9 which acts on the circumferential surface of the suction anchor 2 R it is possible to prevent reaching the _U, thus, as in the prior art, the tensile force P can be suction anchors 2 exceeds the maximum pull-out resistance force P _U to prevent a situation withdrawn from seabed 9 .

There is also a limit to the water pressure difference that can be generated by the drainage operation by the drainage pump 10, and it is assumed that a tensile force P 'exceeding the maximum withdrawal resistance P _U ' acts as shown in FIG. In this case, as shown in the same drawing, it is inevitable that the drawing displacement w 'occurs in the suction anchor 2, but even in such a case, the drawing displacement w' is drawn when the drainage operation is not performed. It can be more sufficiently suppressed.

  In the present embodiment, the floating body structure is the wind power generation facility 6, but instead of this, an oil drilling platform or the like may be used as the floating body structure.

  Further, although not particularly mentioned in the present embodiment, the pressure difference between the inside and the outside of the suction anchor 2 caused by the operation of the drainage pump 10 increases stepwise toward the predetermined maximum pressure difference, ie, the limit suction. The arithmetic and control unit 8 may be configured as follows.

  Specifically, the limit suction is determined in advance from ground conditions etc., and when this is set to 100%, the pressure difference between inside and outside of the suction anchor 2 increases stepwise, for example to 25%, 50%, 75%. Thus, the drainage pump 10 is driven and controlled by the arithmetic and control unit 8.

  And every time the pressure difference inside and outside the suction anchor 2 reaches the above-mentioned each stage, the operation of the drainage pump 10 is suspended, then, after confirming the condition of the seabed ground 9, if there is no problem, it goes to the next stage The operation of the drainage pump 10 is resumed, and if there is a problem, the operation of the drainage pump 10 is stopped.

  According to this configuration, the progress of the pressure difference formation inside and outside the suction anchor 2 is too fast or the pressure difference is too large, so that the effective stress of the seabed ground 9 is rapidly reduced, which may cause boiling or the like. It is possible to prevent the occurrence of the failure phenomenon of the seabed ground 9 and the decrease in the withdrawal resistance of the suction anchor 2 accompanying it.

  Note that, instead of the above-described stepwise increase, the arithmetic and control unit 8 causes the pressure difference between the inside and the outside of the suction anchor 2 generated by the operation of the drainage pump 10 to continuously and gradually increase toward the predetermined maximum pressure difference. The drainage pump may be configured to operate.

  Also in this configuration, the condition of the submarine ground 9 is continuously monitored, and if there is no problem, the operation of the drainage pump 10 can be continued, and if there is a problem, the operation can be stopped. You can get

Second Embodiment
Next, a second embodiment will be described. The same reference numerals are given to parts substantially the same as those of the first embodiment, and the description thereof is omitted.

  FIG. 4 is a layout view and a block diagram of a suction anchor withdrawal prevention system 41 according to a second embodiment. As can be seen from these figures, the suction anchor withdrawal prevention system 41 according to the present embodiment is applied to the same suction anchor 2 as that of the first embodiment, and is connected to the internal space of the suction anchor. The drainage pump 10, the water level gauge 42 as a measuring means for measuring the tide level around the wind power generation facility 6, and the arithmetic and control unit 8 for controlling the operation of the drainage pump 10 are provided.

  The water level gauge 42 can be configured by, for example, a light detection non-contact sensor.

  The arithmetic control device 8 estimates the tensile force generated in the tension cord 5 using the measurement result by the water level gauge 42, and does the estimated tensile force exceed or exceed a predetermined allowable tensile force? If it is determined that the tensile force may exceed or exceed the allowable tensile force, the drainage pump 10 is operated to drain the water spreading to the internal space of the suction anchor 2.

  In order to prevent withdrawal of the suction anchor 2 using the suction anchor withdrawal prevention system 41 according to the present embodiment, first, the tide level around the wind power generation facility 6 is measured by the water level gauge 42 and the measurement result is used The arithmetic and control unit 8 estimates the tensile force P generated in the tension cord 5.

  In estimating the tensile force P, the relationship between the tide level around the wind power generation facility 6 and the tensile force generated in the tension cord 5 is associated in advance by experiment or analysis, and is stored in the form of a table in the arithmetic and control unit 8 Then, the tensile force P corresponding to the tide level may be read out by comparing the tide level data measured by the water level gauge 42 with the table.

  The measurement of the tide level by the water level gauge 42 may be performed continuously or at any time interval, but in the latter case, the measurement interval is relatively long when the sea is quiet. If the construction is made relatively short when the sea is rough, it is possible to estimate and monitor the tensile force P generated in the tension cord 5 efficiently.

  Next, the arithmetic and control unit 8 determines whether or not the estimated tensile force P exceeds or exceeds a predetermined allowable tensile force. The direct measurement is almost the same as the measurement by the water level gauge 42, except for the measurement, so the description thereof is omitted here.

  As described above, according to the suction anchor withdrawal prevention system 41 and method according to the present embodiment, as in the first embodiment, a water pressure difference is generated between the inside and the outside of the suction anchor 2 by the drainage operation by the drainage pump 10, Since the suction anchor 2 is pushed downward by the hydraulic pressure difference to resist the tensile force P, even if the tensile force P generated in the tension cord 5 fluctuates in the increasing direction due to wave, wind or tide fluctuation. The increase can be supported by the pushing force ΔS due to the above-described water pressure difference.

  Hereinafter, the same effects as those of the first embodiment can be obtained in the present embodiment as well, but the descriptions thereof will be omitted here to avoid duplication.

  In the present embodiment, the floating body structure is the wind power generation facility 6, but instead of this, an oil drilling platform or the like may be used as the floating body structure.

  Further, in the present embodiment, the tide level is selected as a measurement target for estimating the tensile force P generated in the tense cord 5, but if it is a measurable physical fluctuation characteristic caused by weather, the tensile force P can be estimated. It is arbitrary what kind of thing is to be measured, and it is possible to measure waves, wind power, atmospheric pressure, water pressure and the like instead of the tide level.

  Furthermore, as a measurement target for estimating the tensile force P generated in the tension cord 5, the posture change of the wind power generation facility 6 may be used instead of the above-described weather factor, or the amount of power generation may be used.

  Also in these cases, if the rotation angle of, for example, the center of gravity around the wind power generation facility 6 and the fluctuation characteristic of the tensile force in the tension cord 5 are associated in advance, the tensile force of the tension cord 5 can be measured by measuring the rotation angle. Since the relationship between the amount of power generation and the wind power is grasped in advance as the specification of the wind power generation facility 6, the relationship between the wind power and the fluctuation characteristic of the tensile force in the tension cord 5 is preliminarily obtained by experiment or analysis. If linked, it is also possible to estimate the tension of the tension cord 5 from the amount of power generation of the wind power generation facility 6.

  Further, although not particularly mentioned in the present embodiment, as in the first embodiment, the pressure difference between the inside and the outside of the suction anchor 2 caused by the operation of the drainage pump 10 is directed to the predetermined maximum pressure difference, ie, the limit suction. The arithmetic control unit 8 may be configured to increase gradually or continuously increase continuously.

  In addition, about the effect, it is the same as that of 1st Embodiment, Therefore The description is abbreviate | omitted here.

1, 41 Suction anchor pullout prevention system 2 Suction anchor 3 Tubular peripheral wall 4 Top plate 5 Tension (tension material)
6 Wind power generation facility (floating structure)
7 Load cell (measuring means)
8 Arithmetic control unit (arithmetic control means)
9 Submarine ground (underwater ground)
10 Drainage pump 42 Water level gauge (measuring means)

Claims (5)

In a method for preventing withdrawal of a suction anchor, which comprises a cylindrical peripheral wall portion and a top plate portion closing one end of the cylindrical peripheral wall portion, the cylindrical peripheral wall portion being penetrated into the water bottom ground,
Measure the tensile force of the tensile material connecting the suction anchor and the floating structure,
A method for preventing withdrawal of a suction anchor, comprising draining water in the suction anchor when the tensile force exceeds or is likely to exceed a predetermined allowable tensile force. In a method for preventing withdrawal of a suction anchor, which comprises a cylindrical peripheral wall portion and a top plate portion closing one end of the cylindrical peripheral wall portion, the cylindrical peripheral wall portion being penetrated into the water bottom ground,
Waves around the floating structure, which are connected to the suction anchor via tension members, tide fluctuations, wind power and other meteorological elements, or posture changes of the floating structure, or when the floating structure is a wind power generation facility Measure the amount of power generation,
The tensile force of the tensile material is estimated using the result obtained in the measurement step,
A method for preventing withdrawal of a suction anchor, comprising draining water in the suction anchor when the tensile force exceeds or is likely to exceed a predetermined allowable tensile force. A suction anchor pullout preventing system comprising a cylindrical peripheral wall portion and a top plate portion closing one end thereof, the floating body structure being connected via a tensile material in a state where the cylindrical peripheral wall portion is penetrated into the underwater ground;
It comprises: a drainage pump communicatively connected to the internal space of the suction anchor; measurement means for measuring the tensile force generated in the tension member; and arithmetic control means for controlling the operation of the drainage pump, the arithmetic control means Determining whether the tensile force measured by the measuring means exceeds or exceeds a predetermined allowable tensile force, and the tensile force may exceed or exceed the allowable tensile force; A suction anchor withdrawal prevention system characterized in that it is adapted to operate a pump. A suction anchor pullout preventing system comprising a cylindrical peripheral wall portion and a top plate portion closing one end thereof, the floating body structure being connected via a tensile material in a state where the cylindrical peripheral wall portion is penetrated into the underwater ground;
The drainage pump connected to the internal space of the suction anchor, waves around the floating structure, tide fluctuation, wind power and other meteorological elements or posture changes of the floating structure are measured or the floating structure is a wind power generator In the case of a facility, it comprises measurement means for measuring the amount of power generation, and arithmetic control means for controlling the operation of the drainage pump, wherein the arithmetic control means pulls the tension material using the measurement result by the measurement means. The force is estimated, it is determined whether or not the tensile force exceeds or exceeds a predetermined allowable tensile force, and when the tensile force is likely to exceed or exceed the allowable tensile force, the drainage pump is A suction anchor withdrawal prevention system characterized in that it is operated. The arithmetic control means is configured such that the pressure difference between the inside and the outside of the suction anchor caused by the operation of the drainage pump increases stepwise or continuously increases toward a predetermined maximum pressure difference. Or the withdrawal prevention system of the suction anchor according to claim 4.

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