Deflection-Prevention Structure of Mandrel for Marine PVD Application and PVD Construction Method Using the Same

Abstract

The present invention relates to a bending prevention structure for a mandrel for marine PVD construction and a PVD construction method using the same. More specifically, the invention is characterized by comprising: a barge that floats on the sea and moves and aligns to a PVD construction site; a multi-axis PVD construction equipment installed on the barge that supplies PVD to the mandrel and drives the mandrel to insert and withdraw it from the ground; a hollow square end leader vertically fixed in the lower water of a penetration hole communicating with the sea surface on the barge at a number and spacing corresponding to the mandrel; an inner guide fixedly installed by a support member with the same length as the square end leader inside the square end leader; a mandrel guide disposed inside the square end leader and guiding the mandrel by moving up and down along the inside of the inner guide by the operation of a winch; a solenoid having a plunger installed at the upper end adjacent to the lower end of the mandrel guide to fix and separate the mandrel; and a cutting device installed on the opposite side of the solenoid to cut the poured PVD.

Description

Technology Field

[0001] The present invention relates to a bending prevention structure for a mandrel for marine PVD construction and a PVD construction method using the same, which prevents the mandrel from bending and deforming due to ocean currents during the construction process of installing PVD on soft seabed at sea, thereby improving verticality, construction accuracy, and safety. Background Technology

[0002] The PVD method for improving soft ground offshore is an effective method for promoting ground consolidation and ensuring the stability of soft ground by inserting a vertical drain (PVD) into the ground. In this offshore PVD construction, offshore PVD construction equipment is installed on a barge, which serves as a work platform, and the PVD is installed in the soft ground by pressing a long case-shaped structure called a mandrel, into the ground.

[0003] However, the marine environment is subject to unstable elements such as waves, currents, and tides that hinder the vertical insertion of the mandrel. In particular, since the mandrel has a long, slender shape and a construction depth of tens of meters, if the water depth increases or it is exposed to strong currents, the mandrel receives external lateral forces and bends.

[0004] This bending phenomenon caused the PVD to be inserted out of the planned position or verticality, resulting in irregular drainage distances and a deterioration in the quality of ground improvement. Furthermore, continuous bending affected not only the mandrel itself but also other parts of the PVD construction equipment, causing damage. This led to many problems, such as shortened equipment lifespan and increased maintenance costs, as well as delays in the construction period due to repair time and rework caused by equipment damage.

[0005] Registered Patent No. 10-2425461 is disclosed as improving construction quality by maintaining the verticality of the mandrel in PVD construction.

[0006] The above prior art is a structure in which a main guide is installed to guide a PBD casing (mandrel) that moves up and down along a leader installed in a drilling machine, and an auxiliary guide is installed to move up and down within a certain distance range relative to the bottom of the leader, thereby allowing the mandrel to move up and down along the main guide and the auxiliary guide, so as to maintain the verticality of the mandrel. The main guide is fixed to a leader installed on the hull, and only the auxiliary guide moves up and down at a deep seabed, thereby maintaining the verticality of the mandrel.

[0007] Therefore, although the mandrel has the advantage of maintaining verticality through the main guide and auxiliary guide, the auxiliary guide is also long enough to accommodate the mandrel, so there are limitations in protecting the mandrel from strong currents such as waves and tides using only the auxiliary guide, and there is a problem that it is not easy to safely raise and lower the long and heavy auxiliary guide using the compression drive roller installed on the leader.

[0008] In particular, the above prior art has a problem in that continuous operation is not easy and cumbersome because, since the above structure is installed on construction equipment on the hull, when installing an anchor plate at the end of the cut PVD for the next PVD pouring operation after pouring and cutting the PVD, both the mandrel and the auxiliary guide must be raised onto the work platform of the hull. The problem to be solved

[0009] The objective of the present invention is to solve such problems by providing a bending prevention structure for a mandrel for marine PVD construction and a PVD construction method using the same, which can improve the verticality of the mandrel and ensure accuracy regarding the PVD pouring position by protecting the mandrel from strong ocean currents and preventing bending by means of a square end leader installed on a barge and installed below the water surface and a mandrel guide that moves up and down along the square end leader, thereby improving construction quality and efficiency. means of solving the problem

[0010] The present invention, as a means to achieve this objective, comprises: a barge floating on the sea and moving and aligning to a PVD construction site; a multi-axis PVD construction device installed on the barge to supply PVD to a mandrel and to drive the mandrel to insert and withdraw it from the seabed; a square end leader formed of a hollow truss structure, vertically fixed in the lower water of a penetration hole formed on the barge and communicating with the sea surface at intervals corresponding to the number of mandrels; an inner guide fixedly installed by a support member so as to extend along the longitudinal direction of the square end leader inside the square end leader; a mandrel guide disposed inside the square end leader and guiding the mandrel while moving up and down along the interior of the inner guide; a winch connected to the mandrel guide to raise and lower the mandrel guide; a solenoid installed at the upper end near the bottom of the mandrel guide and selectively connecting or disconnecting the mandrel to the mandrel guide by means of a plunger that moves back and forth; and the mandrel A control means for controlling the operation of the winch and solenoid so that the guide descends to a position close to the seabed while combined with the mandrel; and a cutting device installed on the mandrel guide for cutting the poured PVD; comprising

[0011] The above control means provides a bending prevention structure for a mandrel for marine PVD construction, characterized in that when the mandrel descends into the interior of the mandrel guide and the lower end of the mandrel is exposed to the lower part of the mandrel guide, the solenoid is activated to integrally combine the mandrel and the mandrel guide, and when the mandrel and the mandrel guide descend together to a position close to the seabed, the operation of the winch is stopped and the operation of the solenoid is released at the same time so that the mandrel guide is stopped and only the mandrel continues to descend to the seabed.

[0012] delete

[0013] delete

[0014] delete

[0015] delete

[0016] delete

[0017] delete

[0018] The present invention relates to a method for constructing PVD on soft ground offshore using a mandrel bending prevention structure, wherein

[0019] delete

[0020] delete

[0021] (a) A step of installing a mandrel bending prevention structure at the lower part of a barge's penetration hole, the structure comprising square end leaders installed at intervals and numbers corresponding to the mandrels, a mandrel guide that is raised and lowered along the inner guide using a winch and a wire rope, a solenoid having a plunger for fixing and separating the mandrel on both upper sides adjacent to the bottom of the mandrel guide, and a cutting device for cutting the poured PVD;

[0022] (b) A step in which the mandrel guide is raised to the inner guide of the square end leader and fixed by the winding operation of the winch, and the mandrel with the PVD inserted is lowered by the driving device so that its lower end is exposed to the bottom of the mandrel guide, and at the same time the solenoid is activated and its plunger is electrically connected to the mandrel so that the mandrel guide and the mandrel are interlocked as a single unit;

[0023] (c) A step in which, in step (b) above, the solenoid is actuated so that the mandrel guide and the mandrel are linked as a single unit, and at the same time, the mandrel and the mandrel guide descend simultaneously by releasing the winch;

[0024] (d) When the lower end of the mandrel, which is descending together with the mandrel guide in step (c) above, reaches a position close to the seabed, the operation of the winch is stopped by a control signal of the descent position control means so that the mandrel guide stops at a position close to the seabed, and at the same time, the operation of the solenoid linked integrally with the mandrel guide is released so that the mandrel is separated from the mandrel guide;

[0025] (e) A step in which the mandrel separated from the mandrel guide in step (d) above continues to descend and is pressed into the seabed ground to install the PVD;

[0026] (f) A step of withdrawing the mandrel and cutting the PVD by a cutting device once the PVD casting is completed;

[0027] (g) A step of raising the mandrel guide, which has been lowered into the water and stopped, back to its original position by operating a winch;

[0028] A PVD construction method using a bending prevention structure of a mandrel for marine PVD construction, characterized by being composed of Effects of the invention

[0029] The present invention, through a multi-stage reinforced support structure of square end leaders, internal guides, and mandrel guides at the bottom of the barge, is completely protected from external lateral forces such as ocean currents and tides throughout the entire section where the mandrel is inserted from the sea surface into the ground, thereby fundamentally preventing bending of the mandrel and ensuring verticality. This ensures that the PVD drainage material is always inserted vertically into the ground, optimizing the ground improvement effect and guaranteeing uniformity, thereby improving construction quality and significantly reducing the rework rate, which shortens the overall construction period and improves economic efficiency.

[0030] In addition, it is possible to achieve verticality of the mandrel and stable casting even in unpredictable marine environments with adverse conditions where PVD construction was impossible with existing technology due to strong currents / tides or deep water, thereby dramatically expanding the scope of application for marine ground improvement technology.

[0031] In addition, by eliminating unnecessary lateral loads and bending stresses applied to the mandrel, wear and damage to the mandrel and related drive devices are minimized, extending their lifespan and reducing maintenance costs. Brief explanation of the drawing

[0032] FIG. 1 is an exemplary diagram of the construction state of PVD according to the present invention. FIG. 2 is an exemplary view seen from the bow of a barge showing the square end leader, underwater mandrel guide, and mandrel of the present invention installed on a multi-axis marine leader. FIG. 3 is a partially exploded example of a bending prevention structure of a mandrel according to one embodiment of the present invention. FIG. 4 is a cross-sectional view along the line "A-A" of FIG. 1. FIG. 5 is a cross-sectional view of the combined state of the square end leader and the mandrel guide of the present invention. FIG. 6 is an example of a state in which a mandrel is fixed by a solenoid inside a mandrel guide and is integrally linked. Fig. 7 is an example of the state of cutting a mandrel installed in the ground. Figures 8 (a), (b), (c), (d), (e), and (f) are exemplary diagrams showing the construction state according to the present invention in stages. FIG. 9 is a block diagram illustrating a construction method according to an embodiment of the present invention in chronological order. Specific details for implementing the invention

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, focusing on the parts necessary to understand the operation and function according to the present invention.

[0034] The embodiments described in this specification and the configurations illustrated in the drawings are merely one preferred embodiment of the present invention and do not represent all of the technical concepts of the present invention; therefore, it should be understood that various modifications capable of replacing them may exist at the time of filing this application.

[0035] In describing the embodiments of the present invention, unnecessary technical details that are well known in the technical field to which the present invention belongs and are not directly related to the present invention are omitted to ensure clearer communication without obscuring the essence of the invention.

[0036] Referring to FIGS. 1 to 4, the bending prevention structure of the mandrel for marine PVD construction according to the present invention is,

[0037] A barge (B) floating on the sea and moving and aligning to the PVD construction site;

[0038] A multi-axis PVD construction device (100) installed on the above barge (B) to supply PVD (10) to a mandrel (20) and drive the mandrel (20) to insert into and withdraw from the ground;

[0039] A hollow square end leader (200) vertically fixed in the lower water of the penetrating hole (30) communicating with the sea surface on the above barge (B) at a number and spacing corresponding to the mandrel (20);

[0040] An inner guide (210) fixedly installed by a support rod (201) with the same length inside the square end leader (200);

[0041] A mandrel guide (300) positioned inside the square end leader (200) and guiding the mandrel (20) by moving up and down along the inside of the mandrel guide (300) by the operation of a winch (310); and

[0042] A solenoid (320) having a plunger (321) installed at the upper portion adjacent to the lower portion of the mandrel guide (300) to fix and separate the mandrel (20);

[0043] It is characterized by being configured to include a cutting device (400) installed on the opposite side of the above solenoid (320) to cut the poured PVD (10).

[0044] The present invention, configured as described above, protects the mandrel (20) that installs PVD (10) on the seabed underwater from strong ocean currents to improve verticality, and the specific technical configuration and effects of operation are explained with reference to the drawings of the embodiments.

[0045] First, the barge (B) equipped with PVD construction equipment (100) moves to a work area on the sea by a tugboat.

[0046] The marine PVD construction equipment (100) may include a multi-axis marine leader (120), a mandrel (20) for inserting the PVD (10), a drive device (130) for operating the mandrel (20) up and down, a GPS control room for accurately controlling the position of the PVD (10), a construction control room, etc.

[0047] The above-mentioned multi-axis marine leader (120) is a vertical structure in the form of a steel frame installed on a tower-type frame (110), and is equipped with a mandrel (20), a driving device (130) for operating the mandrel (20), a wire, a pulley, etc., and is installed vertically and firmly so as to support the load acting during the PVD (10) insertion and extraction process.

[0048] These multi-axis marine leaders (120) are installed in a row with 10 to 20 or more at regular intervals on the frame (110) to allow PVD (10) to be poured and pressed into the work section in a row simultaneously, and the leaders (120) can be moved individually by a separate transfer device to adjust the spacing between the leaders (120).

[0049] The above-mentioned hollow square end leader (200) is fixedly installed at the bottom of the through hole (30) through which the mandrel (20) is raised and lowered by penetrating the barge (B), and can be manufactured integrally with the barge (B) or installed through an independent frame (110) connected to the barge (B).

[0050] The square end leader (200) is formed with a hollow internal structure to minimize fluid resistance of seawater and smoothly guide the raising and lowering of the mandrel guide (300) and the mandrel (20), and is equipped with sufficient length and rigidity to primarily block external lateral forces and protect the lowering path of the mandrel (20) from tides and currents, thereby preventing bending of the mandrel (20).

[0051] The square end leader (200) may be a truss structure connected in a triangle using joint points so that the structural member does not bend as an angle, as an example.

[0052] The length of the above square end leader (200) can be installed to reach a depth of 15 to 20 m from the barge (B), but can be adjusted variably according to the depth.

[0053] The above internal guide is fixedly installed by a support rod (201) with the same length in the internal space of the square end leader (200) and has a structure having the same cross-section as the mandrel guide (300) so that the mandrel guide (300) can freely move up and down, and provides the effect of secondarily blocking external lateral forces underwater while integrated with the square end leader (200).

[0054] The above mandrel guide (300) guides the mandrel by moving up and down along the inside of the inner guide (210) fixed inside the square end leader (200). It is connected to a winch (310) installed on the barge (B) and a wire, and moves up and down according to the winding length of the wire. At the point where the lower end of the mandrel (20) that is descending passes through the mandrel guide (300), the solenoid (320) described later is activated and is linked integrally with the mandrel (20) by the plunger (321). As it descends simultaneously with the mandrel (20) to a position close to the seabed, the mandrel (20) is blocked from external lateral forces in a third manner.

[0055] When the mandrel (20) is not in operation, the mandrel guide (300) is raised by the winding operation of the winch (310) so that its upper end is positioned on the upper part of the inner guide (210). When the mandrel (20) is lowered to pour PVD (10) and is drawn into the interior of the mandrel guide (300), at the point where its lower end is exposed to the lower part of the mandrel guide (300), the solenoid (320) is operated according to the control signal of the control means of the mandrel (20) to be linked integrally with the mandrel (20), and at the same time, the mandrel guide (300) is lowered together with the mandrel (20) by the unwinding operation of the winch (310).

[0056] Additionally, when the mandrel (20) is in a state where it is integrally linked with the mandrel guide (300) and the lower end of the mandrel (20) reaches a position close to the seabed, the release operation of the winch (310) is stopped according to the control signal of the mandrel (20) lowering position control means, and at the same time, the solenoid (320) is released so that only the mandrel (20) continues to descend and is pressed into the seabed.

[0057] In this way, the winch (310) and solenoid (320) are controlled by a sensor and a control unit.

[0058] The mandrel guide (300) described above can be implemented in a structure that is adjustable in length in a telescopic form and varies according to changes in the height of the seabed, in addition to the single body as described above.

[0059] In addition, an electric / hydraulic drive means may also be used instead of a winch (310) for raising and lowering the mandrel guide (300).

[0060] The above solenoid (320) is installed at the upper portion adjacent to the lower portion of the mandrel guide (300) to fix and separate the mandrel (20). A plunger (321) is positioned inside the mandrel guide (300) through a hole penetrating the mandrel guide (300), and temporarily fixes the mandrel (20), which is raised and lowered inside the mandrel guide (300), using a magnetic field generated according to a control signal from the control unit, thereby enabling it to be linked integrally with the mandrel (20).

[0061] That is, as described above, when the mandrel (20) passes through the mandrel guide (300) during PVD (10) pouring, a magnetic field is generated according to a control signal to be synchronized with the mandrel (20) inside, thereby simultaneously lowering the mandrel guide (300) until the mandrel (20) approaches the seabed, thereby protecting the mandrel (20) from ocean currents and preventing bending.

[0062] A series of mechanisms is organically formed in such a way that when the PVD (10) is poured and pulled out by the pressurization of the mandrel (20), the solenoid (320) is released by a control signal so as not to hinder the raising of the mandrel (20), and at the same time, the winch (310) is operated to raise the mandrel guide (300) back to its original position.

[0063] The above cutting device (400) is installed on the opposite side of the solenoid (320) and cuts the PVD (10) when the PVD (10) pouring is completed and the mandrel (20) is pulled out.

[0064] The present invention, configured as described above, has the advantage of improving construction quality, preventing equipment damage, and increasing stability by preventing buckling and bending of the mandrel (20) and maintaining its verticality, as the device for reinforcing the verticality of the mandrel (20) is installed on a barge (B), and the mandrel (20) is protected from external stresses such as ocean currents or tides along the entire length up to a position close to the seabed by the square end leader (200), inner guide (210), and mandrel guide (300).

[0065] Next, a PVD (10) construction method using the bending prevention structure of the marine PVD construction mandrel (20) of the present invention will be explained with reference to FIGS. 8 and 9.

[0066] In a method of constructing PVD (10) on soft ground at sea using a bending prevention structure of a mandrel (20),

[0067] (a) A step (S100) of installing a mandrel (20) bending prevention structure at the bottom of a penetration hole (30) of a barge (B), comprising square end leaders (200) installed at intervals corresponding to the number and spacing of the mandrel (20), a mandrel guide (300) that moves up and down along the inner guide (210) using a winch (310) and a wire rope, a solenoid (320) having a plunger (321) that fixes and separates the mandrel (20) on both upper sides close to the bottom of the mandrel guide (300), and a cutting device (400) that cuts the poured PVD (10);

[0068] (b) A step (S200) in which the mandrel guide (300) is raised to the inner guide (210) of the square end leader (200) and fixed by the winding operation of the winch (310), and the mandrel (20) with the PVD (10) inserted is lowered by the driving device (130) so that the lower end is exposed to the lower part of the mandrel guide (300), and at the same time the solenoid (320) is activated and its plunger (321) is electrically connected to the mandrel (20) so that the mandrel guide (300) and the mandrel (20) are linked as a single unit;

[0069] (c) A step (S300) in which the solenoid (320) is actuated in step (b) above so that the mandrel guide (300) and the mandrel (20) are linked as a single unit, and at the same time the mandrel (20) and the mandrel guide (300) are lowered simultaneously by releasing the winch (310);

[0070] (d) When the lower end of the mandrel (20), which is lowered together with the mandrel guide (300) in step (c) above, reaches a position close to the seabed, the operation of the winch (310) is stopped by a control signal of the lowering position control means so that the mandrel guide (300) stops at a position close to the seabed, and at the same time, the operation of the solenoid (320) that links the mandrel guide (300) with the mandrel (20) is released so that the mandrel (20) is separated from the mandrel guide (300) (S400);

[0071] (e) Step (S500) in which the mandrel (20), separated from the mandrel guide (300) in step (d) above, continues to descend and is pressed into the seabed ground to pour PVD (10);

[0072] (f) Step (S600) of pulling out the mandrel (20) and cutting the PVD (10) by the cutting device (400) when the PVD (10) pouring is completed;

[0073] (g) A step (S700) of raising the mandrel guide (300), which has been lowered into the water and stopped, back to its original position by operating the winch (310);

[0074] It consists of.

[0075] The construction method of the present invention, carried out in such steps, utilizes a square end leader (200), an internal guide (210), and a mandrel guide (300) installed on a barge (B) and positioned underwater to protect the entire process of the mandrel (20) moving to the seabed from external stress, thereby maintaining perfect verticality.

[0076] In particular, the mandrel (20) is supported by a very sturdy truss-shaped square end leader (200) and an internal guide (210) up to approximately 2 / 3 of the depth from the barge (B) to the seabed, and the remaining depth is supported by a mandrel guide (300) up to a position close to the seabed, so the verticality of the mandrel (20) is reinforced, which enables accurate and effective construction of the PVD (10) in extreme marine environments.

[0077] Although the above description explains the technical concept of the present invention using the PVD (10) method as an example, it can be equally applied to the PBD method, which is an identical vertical drainage method. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0078] B : Barge 10 : PVD 20 : Mandrel 30 : Penetrating hole 100 : PVD Construction Equipment 110 : Frame 120 : Leader 130 : Drive unit 200 : Square End Reader 201 : Support interval 210 : Interior Guide 300 : Mandrel Guide 310 : Winch 320 : Solenoid 321 : Plunger 400 : Cutting device

Claims

Claim 1 A barge floating on the sea and moving and aligning to the PVD construction site; a multi-axis PVD construction device installed on the barge to supply PVD to a mandrel and drive the mandrel to insert and withdraw it from the seabed; a square end leader formed of a hollow truss structure, vertically fixed in the lower water of a penetration hole formed on the barge and communicating with the sea surface at intervals corresponding to the number of mandrels; an inner guide fixedly installed by a support rod so as to extend along the longitudinal direction of the square end leader inside the square end leader; a mandrel guide disposed inside the square end leader and guiding the mandrel while moving up and down along the interior of the inner guide; a winch connected to the mandrel guide to raise and lower the mandrel guide; a solenoid installed at the upper end near the bottom of the mandrel guide and selectively connecting or disconnecting the mandrel to the mandrel guide by means of a plunger that moves back and forth; and a state in which the mandrel guide is connected to the mandrel A bending prevention structure for a mandrel for marine PVD construction, comprising: a control means for controlling the operation of the winch and solenoid to lower the mandrel to a position close to the seabed; and a cutting device installed on the mandrel guide to cut the poured PVD; wherein the control means is configured such that when the mandrel descends into the interior of the mandrel guide and the lower end of the mandrel is exposed to the lower part of the mandrel guide, the solenoid is operated to integrally combine the mandrel and the mandrel guide, and when the mandrel and the mandrel guide descend together to a position close to the seabed, the operation of the winch is stopped and the operation of the solenoid is released at the same time so that the mandrel guide is stopped and only the mandrel continues to descend to the seabed. Claim 2 delete Claim 3 delete Claim 4 A method for constructing PVD on soft seabed using a mandrel bending prevention structure, comprising: (a) installing a mandrel bending prevention structure at the bottom of a barge's penetration hole, the structure comprising square end leaders installed at intervals and numbers corresponding to the mandrels, a mandrel guide that is raised and lowered by a winch and a wire rope along the mandrel guide's inner guide, a solenoid having a plunger for fixing and separating the mandrel on both upper sides adjacent to the bottom of the mandrel guide, and a cutting device for cutting the poured PVD; (b) a step in which, while the mandrel guide is raised to the inner guide of the square end leader and fixed by the winding operation of the winch, the mandrel with the PVD inserted is lowered by a driving device so that its lower end is exposed to the bottom of the mandrel guide, and at the same time, the solenoid is activated and its plunger is electrically connected to the mandrel so that the mandrel guide and the mandrel are interlocked as a single unit; (c) in step (b), the solenoid is activated so that the mandrel guide and the mandrel are interlocked as a single unit A step in which the mandrel and the mandrel guide descend simultaneously by releasing the winch while being linked; (d) a step in which, when the lower end of the mandrel descending together with the mandrel guide in step (c) reaches a position close to the seabed, the operation of the winch is stopped by a control signal of the descent position control means so that the mandrel guide stops at a position close to the seabed, and at the same time, the operation of the solenoid linked integrally with the mandrel guide is released so that the mandrel separates from the mandrel guide; (e) a step in which the mandrel separated from the mandrel guide in step (d) continues to descend and is pressed into the seabed ground to cast the PVD; (f) a step in which, when the PVD casting is completed, the mandrel is withdrawn and the PVD is cut by a cutting device; (g) a step in which the mandrel guide, which has descended and stopped underwater, is raised by the operation of the winch and returned to its original position; characterized by a PVD construction method using a bending prevention structure of a mandrel for marine PVD construction.

Images