Suction bucket foundation construction method and construction management system

Abstract

To provide a suction bucket foundation construction method and a construction management system which facilitate management of suction bucket foundation construction without inhibiting penetration of a suction bucket.SOLUTION: A suction bucket foundation construction method detects a grounding state (grounding of first detection point, second detection point, third detection point and fourth detection point) of a suction bucket 1 on the basis of detection signals of optical fiber sensors S1, S2, S3 and S4 mounted on the suction bucket 1, and adjusts the suction bucket 1 to be horizontal on the basis of the detected grounding state of the suction bucket 1. Since the optical fiber sensors S1, S2, S3 and S4 do not require waterproof treatment, management of suction bucket foundation construction is easy. The optical fiber sensors S1, S2, S3 and S4 have outer diameters of approximately several mm, and accordingly do not hinder penetration of the suction bucket 1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a suction bucket foundation construction method and a construction management system applicable to foundation construction of fixed-type offshore wind power generation facilities and the like.

Background Art

[0002] The suction bucket foundation construction method applicable to foundation construction of fixed-type offshore wind power generation facilities and the like is a method of draining the inside of a cylindrical suction bucket that has landed on the seabed ground and making the pressure inside the suction bucket lower than the hydrostatic pressure to penetrate the suction bucket into the seabed ground (see, for example, "Patent Document 1").

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a suction bucket foundation construction method, in order to suppress the occurrence of phenomena such as maintaining the verticality of the main body and the occurrence of piping during construction, it is necessary to land the suction bucket horizontally. In the conventional suction bucket foundation construction method, the landing state of the suction bucket has been confirmed by the image of a camera attached to an underwater drone or by visual inspection by a diver, but it becomes difficult to confirm when the visibility decreases due to turbidity or the like.

[0005] On the other hand, there is a method of providing a plurality (for example, three) of pressure sensors at intervals in the circumferential direction at the lower end position of the suction bucket and adjusting the suction bucket horizontally based on the electrical signals of these pressure sensors. However, the pressure sensors protruding from the side wall of the suction bucket may become a resistance and hinder the penetration of the suction bucket. Furthermore, since the pressure sensors use electrical signals, waterproofing treatment is required, and handling becomes complicated.

[0006] The present invention aims to provide a suction bucket foundation construction method and construction management system that does not hinder the penetration of the suction bucket and facilitates the management of suction bucket foundation construction. [Means for solving the problem]

[0007] The present invention relates to a suction bucket foundation construction method, which involves sinking a covered cylindrical suction bucket to the seabed, and includes: an attachment step of attaching one side of an optical fiber sensor to the suction bucket; a sinking step of lowering the suction bucket, which is suspended by a crane, toward the seabed; a calculation step of calculating the landing state of the suction bucket based on the detection signal of the optical fiber sensor; a display step of displaying the calculated landing state of the suction bucket on a display; and an operation step of operating the suction bucket while checking the landing state of the suction bucket displayed on the display in real time. In the mounting step, a plurality of first optical fiber sensors are attached to the suction bucket, and the sensor portions of the plurality of first optical fiber sensors are provided at the lower end of the suction bucket and at equal intervals in the circumferential direction of the suction bucket. In the calculation step, the bottoming state of the suction bucket is calculated based on the detection signals of the plurality of first optical fiber sensors, and in the operation step, the suction bucket is adjusted horizontally while checking the bottoming state of the suction bucket displayed on the display in real time. It is characterized by the following: The construction management system of the present invention is a construction management system applied to a suction bucket foundation construction method in which a covered cylindrical suction bucket is settled and sunk into the seabed ground, and includes: an optical fiber sensor attached to one side of the suction bucket; a control device that calculates the settling state of the suction bucket based on the detection signal of the optical fiber sensor; and a display that displays the calculated settling state of the suction bucket. The optical fiber sensor includes a plurality of first optical fiber sensors, the sensor portions of the plurality of first optical fiber sensors are provided at the lower end of the suction bucket and at equal intervals in the circumferential direction of the suction bucket, and the control device calculates the bottoming state of the suction bucket based on the detection signals of the plurality of first optical fiber sensors. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a suction bucket foundation construction method and construction management system that do not hinder the penetration of the suction bucket and facilitate the construction management of the suction bucket foundation. [Brief explanation of the drawing]

[0009] [Figure 1]This is an explanatory diagram of the suction bucket foundation. [Figure 2] This is an explanatory diagram of this embodiment, showing the arrangement of the first optical fiber sensor. [Figure 3] This is an explanatory diagram of this embodiment, showing the arrangement of the second optical fiber sensor. [Figure 4] This is an explanatory diagram of this embodiment, showing the arrangement of the third optical fiber sensor. [Figure 5] This is an explanatory diagram of this embodiment, and is a conceptual diagram of a construction management system. [Figure 6] This is an explanatory diagram of this embodiment, and is a flowchart of the suction bucket foundation construction method. [Figure 7] This is an explanatory diagram of this embodiment, showing the suction bucket in a state where it is resting on the seabed. [Figure 8] This is an explanatory diagram of this embodiment, showing the state in which the inside of the suction bucket is being drained. [Modes for carrying out the invention]

[0010] One embodiment of the present invention will be described with reference to the attached diagram. In this embodiment, a suction bucket foundation method applicable to the foundation construction of a bottom-fixed offshore power generation facility will be described as an example. For convenience, the vertical direction in Figure 1 will be referred to simply as the vertical direction. As shown in Figure 1, the suction bucket 1 is formed in the shape of a covered cylindrical shape. The suction bucket 1 has cylindrical side walls 3 and a top wall 6 that closes the upper end opening of the side walls 3. A tower 8 is erected in the center of the upper surface of the top wall 6.

[0011] The suction bucket foundation construction method according to this embodiment is applied to a construction management system 10 (see Figure 5) for managing the construction of the suction bucket foundation. As shown in Figure 2 or Figure 5, the construction management system 10 has a plurality of optical fiber sensors S1, S2, S3, S4 (first optical fiber sensors) (four in this embodiment). One side of the optical fiber sensors S1, S2, S3, S4 is attached to the outer circumferential surface 3 of the side wall 2 of the suction bucket 1. Also, one side of the optical fiber sensors S1, S2, S3, S4 is attached along the busbar of the side wall 2 of the suction bucket 1 (the busbar of the cylinder including the outer circumferential surface 3). Furthermore, one side of the optical fiber sensors S1, S2, S3 is arranged at equal intervals in the circumferential direction of the outer circumferential surface 3 of the side wall 2 of the suction bucket 1. Note that for convenience, the optical fiber sensors S1, S2, S3, S4 are not shown at equal intervals in Figure 2, but in reality they are spaced at 90° intervals around the centerline of the suction bucket 1.

[0012] One end of each optical fiber sensor S1, S2, S3, and S4 protrudes downward beyond the lower end surface 5 (lower end position) of the suction bucket 1. Sensor sections s1, s2, s3, and s4 (detection points) made of diffraction gratings (FBG: Fiber Bragg Gratings) are provided at the ends of the optical fiber sensors S1, S2, S3, and S4. Hereinafter, as necessary, the sensor section s1 of optical fiber sensor S1 will be referred to as the first detection point of the suction bucket 1, the sensor section s2 of optical fiber sensor S2 as the second detection point of the suction bucket 1, the sensor section s3 of optical fiber sensor S3 as the third detection point of the suction bucket 1, and the sensor section s4 of optical fiber sensor S4 as the fourth detection point of the suction bucket 1. The other ends of the optical fiber sensors S1, S2, S3, and S4 are connected to the optical fiber measuring instrument 11 via optical connectors (not shown).

[0013] As shown in Figure 3 or Figure 5, the construction management system 10 has multiple (n) optical fiber sensors P1, P2, P3...Pn (second optical fiber sensors). One end of each optical fiber sensor P1, P2, P3...Pn is attached to the outer circumferential surface 3 of the side wall 2 of the suction bucket 1. Another end of each optical fiber sensor P1, P2, P3...Pn is attached along the busbar (the cylindrical busbar including the outer circumferential surface 3) of the side wall 2 of the suction bucket 1. Furthermore, each end of each optical fiber sensor P1, P2, P3...Pn is arranged at regular intervals in the circumferential direction of the side wall 2 of the suction bucket 1. The other end of each optical fiber sensor P1, P2, P3...Pn is connected to the optical fiber measuring instrument 12 via an optical connector (not shown).

[0014] The distance between one side of each optical fiber sensor P1, P2, P3...Pn, with respect to the lower end surface 5 (lower end position) of the suction bucket 1, is shortest for optical fiber sensor P1, and increases by a constant distance in the order of optical fiber sensors P1, P2, P3...Pn. Note that one side of optical fiber sensor P1 is positioned above the lower end surface 5 (lower end position) of the suction bucket 1. Sensor sections p1, p2, p3...pn (detection points) made of diffraction gratings (FBG) are provided at the ends of optical fiber sensors P1, P2, P3...Pn. In other words, the distance between the sensor sections p1, p2, p3...pn of optical fiber sensors P1, P2, P3...Pn, with respect to the lower end surface 5 (lower end position) of the suction bucket 1, is shortest for sensor section p1, and increases by a constant distance in the order of sensor sections p1, p2, p3...pn.

[0015] As shown in FIG. 4 or FIG. 5, the construction management system 10 has a plurality (n) of optical fiber sensors Q1, Q2, Q3 ··· Qn (third optical fiber sensors). One side of the optical fiber sensors Q1, Q2, Q3 ··· Qn is attached to the inner peripheral surface 4 of the side wall 2 of the suction bucket 1. Also, one side of the optical fiber sensors Q1, Q2, Q3 ··· Qn is attached along the generatrix of the side wall 2 of the suction bucket 1 (the generatrix of the cylinder including the inner peripheral surface 4). Further, one side of the optical fiber sensors Q1, Q2, Q3 ··· Qn is arranged at regular intervals in the circumferential direction of the side wall 2 of the suction bucket 1. The optical fiber sensors Q1, Q2, Q3 ··· Qn penetrate through the top wall 6 of the suction bucket 1 and extend to the outside of the suction bucket 1, and the other end is connected to an optical fiber measuring instrument 13 via an optical connector (not shown).

[0016] The distance of one side of the optical fiber sensors Q1, Q2, Q3 ··· Qn from the lower end surface 5 (lower end position) of the suction bucket 1 is the shortest for the optical fiber sensor Q1, and increases by a certain distance in the order of the optical fiber sensors Q1, Q2, Q3 ··· Qn. One side of the optical fiber sensor Q1 is arranged above the lower end surface 5 (lower end position) of the suction bucket 1. Sensor portions q1, q2, q3 ··· qn (detection points) made of diffraction gratings (FBGs) are provided at the ends of the optical fiber sensors Q1, Q2, Q3 ··· Qn. In other words, the distance of the sensor portions q1, q2, q3 ··· qn of the optical fiber sensors Q1, Q2, Q3 ··· Qn from the lower end surface 5 (lower end position) of the suction bucket 1 is the shortest for the sensor portion q1, and increases by a certain distance in the order of the sensor portions q1, q2, q3 ··· qn.

[0017] As shown in FIG. 5, the optical fiber measuring device 11 measures the strain generated in the sensor portions s1, s2, s3, s4 (detection points) of the optical fiber sensors S1, S2, S3, S4 based on the change in the wavelength of the light, and transmits a strain detection signal as a measurement result to the control device 15 via an interface (not shown). The control device 15 calculates the landing state (landing state) of the suction bucket 1 that has landed on the water bottom surface 21 based on the strain detection signal transmitted from the optical fiber measuring device 11, and displays the calculation result numerically or as an image on the display 16.

[0018] Further, the optical fiber measuring device 12 measures the strain generated in the sensor portions p1, p2, p3... pn (detection points) of the optical fiber sensors P1, P2, P3... Pn based on the change in the wavelength of the light, and transmits a strain detection signal as a measurement result to the control device 15 via an interface (not shown). The control device 15 calculates the penetration depth D1 of the suction bucket 1 into the underwater ground 20 with the water bottom surface 21 as a reference point based on the strain detection signal (position of the detection point) transmitted from the optical fiber measuring device 12, and displays the calculation result numerically or as an image on the display 16.

[0019] Furthermore, the optical fiber measuring instrument 13 measures the strain generated in the sensor parts q1, q2, q3, ... qn (detection points) of the optical fiber sensors Q1, Q2, Q3, ... qn based on the change in the wavelength of light at the sensor parts q1, q2, q3, ... qn (detection points) of the optical fiber sensors Q1, Q2, Q3, ... qn, and transmits the strain detection signal as a measurement result to the control device 15 via an interface (not shown). Based on the strain detection signal (position of the detection point) transmitted from the optical fiber measuring instrument 13, the control device 15 calculates the height H1 of the internal ground 22 of the suction bucket 1 with the lower end surface 5 as the starting point. In addition, the control device 15 calculates the amount of uplift H2 (H1-D1) of the internal ground 22 of the suction bucket 1 with the bottom surface 21 as the starting point, from the penetration depth D1 of the suction bucket 1 and the height H1 of the internal ground 22, and displays the calculation result numerically or as an image on the display 16.

[0020] Next, the process of the suction bucket foundation construction method using the aforementioned construction management system 10 will be explained based on the flowchart shown in Figure 6. (Installation step) First, attach the optical fiber sensors S1, S2, S3, and S4 (first optical fiber sensors) to the suction bucket 1. (Settlement step) Next, the suction bucket 1 is lifted and lowered into the water by a crane (not shown) installed on the crane ship, and the suction bucket 1 is lowered toward the predetermined landing position ("Step 1" in Figure 6). The landing position on the seabed 21 has been leveled horizontally beforehand. During the sinking of the suction bucket 1, when at least one of the sensor parts s1, s2, s3, and s4 of the optical fiber sensors S1, S2, S3, and S4 detects strain, that is, when at least one of the first, second, third, and fourth detection points of the suction bucket 1 touches the seabed 20, the sinking (movement) of the suction bucket 1 is stopped ("Step 2" in Figure 6). (Calculation step, display step) After stopping the sinking of the suction bucket 1, the bottoming (settling state) of the first, second, and third detection points of the suction bucket 1 is calculated, and the calculation results are displayed on the display 16. (Operation Steps) While checking the bottoming state of the suction bucket 1 on the display 16, adjust the lower end surface 5 of the suction bucket 1 to be horizontal as shown in Figure 7 ("Step 3" in Figure 6). Next, while keeping the lower end surface 5 of the suction bucket 1 horizontal, the weight of the suction bucket 1 causes a portion of the suction bucket 1 (the lower end of the side wall 2) to penetrate into the seabed ground 20 ("Step 4" in Figure 6). Next, as shown in Figure 8, a pump (not shown) is activated to drain the inside of the suction bucket 1, and by lowering the internal pressure of the suction bucket 1 below the hydrostatic pressure, the suction bucket 1 is driven into the seabed ground 20 ("Step 5" in Figure 6). During the penetration of the suction bucket 1, the operator can check the penetration depth D1 of the suction bucket 1 and the amount of uplift H2 (settling state) of the internal ground 22 of the suction bucket 1 in real time via the display 16.

[0021] By the way, in the suction bucket foundation method, it is necessary to ensure that the suction bucket is placed horizontally on the bottom in order to maintain the verticality of the main body and to prevent piping phenomena during construction. In conventional suction bucket foundation methods, the bottoming state of the suction bucket was confirmed by images from a camera attached to an underwater drone or by visual inspection by divers, but confirmation becomes difficult when visibility is reduced due to turbidity, etc. In contrast, in this embodiment, the bottoming state of the suction bucket 1 (bottoming at the first, second, third, and fourth detection points) is detected based on the detection signals from optical fiber sensors S1, S2, S3, and S4 attached to the suction bucket 1, and the suction bucket 1 is adjusted horizontally based on the detected bottoming state of the suction bucket 1. Therefore, the suction bucket foundation can be constructed efficiently without being affected by water turbidity or the like.

[0022] Furthermore, in conventional suction bucket foundation construction methods, the bottoming state of the suction bucket was detected based on electrical signals from pressure sensors attached to the suction bucket. However, the pressure sensors could act as resistance, potentially hindering the penetration of the suction bucket. In addition, because pressure sensors use electrical signals, waterproofing is required, making them cumbersome to handle. In contrast, in this embodiment, the optical fiber sensors S1, S2, S3, and S4 have a diameter of only a few millimeters, so they cannot act as resistance that would hinder the penetration of the suction bucket 1. Furthermore, the detection signals from the sensor parts s1, s2, s3, and s4 of the optical fiber sensors S1, S2, S3, and S4 are optical signals, not electrical signals, making them easy to handle. Furthermore, since the tips of the optical fiber sensors S1, S2, S3, and S4 protrude beyond the suction bucket 1, it is possible to easily understand the situation of the bucket body settling down, both before and after the bucket body has settled.

[0023] Furthermore, in conventional suction bucket foundation construction methods, displacement sensors (contact sensors) were used to measure the amount of ground uplift inside the suction bucket. However, these displacement sensors are susceptible to malfunctions due to the contact point piercing the ground or becoming jammed with sand. Moreover, like pressure sensors, displacement sensors use electrical signals, requiring waterproofing, which made them cumbersome to handle. In contrast, in this embodiment, the penetration depth D1 of the suction bucket 1 into the seabed ground 20 is calculated based on the detection signals of optical fiber sensors P1, P2, P3, ...Pn attached to the outer peripheral surface 3 of the side wall 2 of the suction bucket 1. On the other hand, the height H1 of the internal ground 22 of the suction bucket 1 is calculated based on the detection signals of optical fiber sensors Q1, Q2, Q3 ...Qn attached to the inner peripheral surface 4 of the side wall 2 of the suction bucket 1, with the lower end surface 5 of the suction bucket 1 as the starting point. The amount of uplift H2 of the internal ground 22 of the suction bucket 1 is calculated from the penetration depth D1 of the suction bucket 1 and the height H1 of the internal ground 22, and the calculation result is displayed on the display 16. Therefore, the amount of uplift H2 of the internal ground 22 of the suction bucket 1 can be measured with high accuracy and reliability. [Explanation of symbols]

[0024] 1 suction bucket, 16 displays, S1, S2, S3, S4 fiber optic sensors

Claims

1. A suction bucket foundation construction method involves attaching and sinking a covered cylindrical suction bucket to the seabed ground, A mounting step involves attaching one side of the optical fiber sensor to the suction bucket, A sinking step in which the suction bucket, which is suspended by a crane, is lowered toward the seabed, A calculation step of calculating the landing state of the suction bucket based on the detection signal of the optical fiber sensor, A display step that displays the calculated landing state of the suction bucket on a display, An operation step of operating the suction bucket while checking the landing status of the suction bucket displayed on the aforementioned display in real time, Includes, In the mounting step, a plurality of first optical fiber sensors are attached to the suction bucket, and the sensor portions of the plurality of first optical fiber sensors are provided at the lower end of the suction bucket and at equal intervals in the circumferential direction of the suction bucket. In the calculation step, the bottoming state of the suction bucket is calculated based on the detection signals of the plurality of first optical fiber sensors. A suction bucket foundation construction method characterized in that, in the operation step, the suction bucket is adjusted horizontally while checking the bottoming state of the suction bucket displayed on the display in real time.

2. A suction bucket foundation construction method according to claim 1, In the mounting step, a plurality of second optical fiber sensors are attached to the outer circumferential surface of the suction bucket, and the sensor portions of the plurality of second optical fiber sensors are arranged so that they are at different distances from the lower end position of the suction bucket. A suction bucket foundation construction method characterized in that, in the calculation step, the penetration depth of the suction bucket is calculated based on the detection signals of the plurality of second optical fiber sensors.

3. A suction bucket foundation construction method according to claim 2, In the mounting step, a plurality of third optical fiber sensors are attached to the inner circumferential surface of the suction bucket, and the sensor portions of the plurality of third optical fiber sensors are arranged so that they are at different distances from the lower end position of the suction bucket. A suction bucket foundation construction method characterized in that, in the calculation step, the height of the internal ground of the suction bucket is calculated based on the detection signals of the plurality of third optical fiber sensors, with the lower end position of the suction bucket as the starting point, and further, the amount of uplift of the internal ground of the suction bucket is calculated from the penetration depth of the suction bucket and the height of the internal ground of the suction bucket.

4. A construction management system applicable to a suction bucket foundation construction method in which a covered cylindrical suction bucket is attached to the bottom of a body of water and sunk, An optical fiber sensor, one end of which is attached to the suction bucket, A control device that calculates the landing state of the suction bucket based on the detection signal of the optical fiber sensor, A display that shows the calculated landing state of the suction bucket, Includes, The optical fiber sensor includes a plurality of first optical fiber sensors, The sensor portions of the plurality of first optical fiber sensors are provided at the lower end of the suction bucket and at equal intervals in the circumferential direction of the suction bucket. The control device is characterized by calculating the bottoming state of the suction bucket based on the detection signals of the plurality of first optical fiber sensors.

5. A construction management system according to claim 4, The optical fiber sensor includes a plurality of second optical fiber sensors provided on the outer circumferential surface of the suction bucket, The sensor portions of the plurality of second optical fiber sensors are arranged so that they are at different distances from the lower end position of the suction bucket. The control device is characterized by calculating the penetration depth of the suction bucket based on the detection signals of the plurality of second optical fiber sensors.

6. A construction management system according to claim 5, The optical fiber sensor includes a plurality of third optical fiber sensors provided on the inner circumferential surface of the suction bucket, The sensor portions of the plurality of third optical fiber sensors are arranged so that they are at different distances from the lower end position of the suction bucket. The control device is characterized by calculating the height of the internal ground of the suction bucket based on the detection signals of the plurality of third optical fiber sensors, with the lower end position of the suction bucket as the reference point, and calculating the amount of uplift of the internal ground of the suction bucket from the penetration depth of the suction bucket and the height of the internal ground of the suction bucket.

Images