Method for assisting cutter suction dredger to pass through narrow channel by grab dredger

Abstract

The invention relates to a method for assisting a cutter suction dredger to pass through a narrow channel by a grab dredger. Comprising the following steps that S1, the stern of the cutter suction dredger is adjusted to face a channel, when the vertical distance between the center of three cable columns of the stern and an inlet of the channel is d1, the cutter suction dredger stops moving, a lower steel pile keeps the position of the dredger, two transverse moving anchors of the bow are thrown, two transverse moving cables are tightened, and anchor braking is completed; s2, the grab dredger slowly gets close to a channel outlet under the assistance of the auxiliary ship, the direction of the grab dredger is adjusted, the body of the grab dredger is transversely arranged at the channel outlet, and when the distance between the stern of the cutter suction dredger and the side of the grab dredger is L1, the lower steel pile of the grab dredger is positioned; s3, the cutter suction dredger lifts the steel pile, a near-side anchor cable winch of the grab dredger takes up a cable, the cutter suction dredger transversely moves a winch to synchronously pay off the cable, the cutter suction dredger slowly moves into the channel, and when the distance between the stern of the cutter suction dredger and the ship side of the grab dredger is L2, the grab dredger stops taking up the cable, the cutter suction dredger stops paying off the cable, and the cutter suction dredger descends the steel pile to be positioned; s4, the grab dredger lifts the steel pile, a far-side anchor cable winch of the grab dredger takes up a cable, a near-side anchor cable is synchronously paid off, the grab dredger slowly gets away from the cutter suction dredger, when the distance between the stern of the cutter suction dredger and the ship side of the grab dredger is L1, the grab dredger stops moving, and the grab dredger is positioned under the steel pile; and S5, repeating the steps S3 and S4. According to the method for assisting the cutter suction dredger in passing through the narrow channel through the grab dredger, the feasibility and safety of operation when the suction dredger passes through the narrow channel are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of cutter suction dredger construction, and in particular relates to a method in which a grab boat assists a cutter suction dredger to pass through a narrow channel. Background Art

[0002] During the process of maneuvering or moving, the dredger suction boat often has to pass through narrow passages, such as the passages between bridge piers when passing under a bridge, the narrow gates when entering a coral reef lagoon, and other narrow waters when moving the boat. Due to the large size of the dredger suction boat, the width of the narrow passage cannot meet the requirements for arranging auxiliary ships such as tugboats to stern against the dredger suction boat. The lateral movement and displacement of the dredger suction boat hull are difficult to control. Under the influence of wind and water flow, the safety risks such as the hull running aground and the hull touching obstacles are extremely high.

[0003] At the same time, grab boats are a common type of dredger in dredging projects. Grab boats and suction dredgers are often used in combination for construction in many dredging projects. Grab boats generally have two sets of positioning methods, one is steel pile positioning, which uses three steel piles to fix the ship's position, and the other is anchor cable positioning, with two positioning anchors in front and behind the hull to fix and move the ship's position. This provides certain powerful conditions for using grab boats to assist suction dredgers in passing through narrow channels. Using the grab boat's own positioning and traction capabilities will help to achieve the safe passage of auxiliary suction dredgers, especially non-self-propelled (without autonomous navigation power) in narrow channels. There is currently no relevant process research, and development and design are needed. Summary of the invention

[0004] The purpose of the present invention is to provide a method for a grab boat to assist a cutter suction boat to pass through a narrow channel, thereby improving the feasibility and safety of the operation of the suction boat when passing through the narrow channel.

[0005] The technical solution adopted by the present invention is: a method for a grab boat to assist a cutter suction boat to pass through a narrow channel comprises the following steps:

[0006] Step S1, adjust the stern of the dredging vessel toward the channel, move the vessel with the assistance of the auxiliary ship and slowly approach the channel, keep the centerline of the hull of the dredging vessel on the centerline of the channel, when the vertical distance from the center of the three cable columns at the stern to the entrance of the channel is d1, the dredging vessel stops moving and lowers steel piles to maintain the ship's position, and the two transverse anchors at the bow are dropped and the two transverse cables are tightened to complete the anchor braking;

[0007] Step S2, with the assistance of the auxiliary ship, the grab ship slowly approaches the channel exit, adjusts the direction of the grab ship, makes the grab ship hull arranged transversely at the channel exit, the center axis of the grab ship hull is perpendicular to the center axis of the cutter suction ship hull, and makes the distance between the stern of the cutter suction ship and the side of the grab ship be L1, positions the steel piles under the grab ship, lowers the two far-side positioning anchors on the grab ship away from the cutter suction ship, removes the two near-side positioning anchors on the grab ship close to the cutter suction ship, and connects the two removed anchor cable heads to the mooring piles at the stern of the cutter suction ship in a cross state, and tightens the four positioning anchor cables on the grab ship;

[0008] Step S3, the auxiliary ship drives away from the cutter suction ship and stands by in the nearby waters, the cutter suction ship lifts the steel pile, the near-side anchor cable winch of the grab ship reels in the cable, and the transverse winch of the cutter suction ship releases the cable synchronously, keeping all cables in a taut state, and the cutter suction ship slowly moves into the channel. When the distance between the stern of the cutter suction ship and the side of the grab ship is L2, the grab ship stops reeling in the cable, the cutter suction ship stops releasing the cable, and the steel pile under the cutter suction ship is positioned;

[0009] Step S4, the grab ship lifts the steel pile, the far side anchor cable winch of the grab ship reels in the cable, and the near side anchor cable is released synchronously, keeping the four positioning anchor cables in a taut state, and the grab ship slowly moves away from the cutter suction ship. When the distance between the stern of the cutter suction ship and the side of the grab ship is L1, the grab ship stops moving, and the steel pile under the grab ship is positioned;

[0010] Step S5, repeating steps S3 and S4 until the hull of the dredging vessel completely drives out of the channel exit, and the safe distance between the dredging head and the channel exit is d2.

[0011] Preferably, let a be the vertical distance from the mooring pile at the stern of the cutter suction ship to the center axis of the hull; b be the distance between the front and rear cable outlet holes of the grab ship; e be the length of the channel; L be the axial length from the stern of the cutter suction ship to the cutter head; the angle between the near-side anchor cable of the grab ship and the center axis of the hull of the cutter suction ship is greater than 30°; then in step S2, Preferably, the safety distance between the stern of the cutter suction dredge and the grab ship is 2a, then in step S3, L2=2a.

[0012] Preferably, the operation of step S3 and step S4 is called a step, and the travel distance of a single step is The total travel distance of the cutter suction dredger is L+e+d1+d2, and the required number of steps n is expressed as:

[0013]

[0014] The advantages and positive effects of the present invention are:

[0015] The present invention provides a method for a grab boat to assist a dredger suction boat to pass through a narrow channel. The grab boat configured at the construction site is used as a traction facility for the dredger suction boat to pass through the narrow channel. By establishing a connection between the proximal positioning anchor cable of the grab boat and the cable pile at the stern of the dredger suction boat and positioning the anchor cables in a cross-crossed state, the grab boat can produce a stable pulling effect on the dredger suction boat. By throwing the transverse anchor of the dredger suction boat and throwing the two distal positioning anchors of the grab boat and tightening each anchor cable, it is effectively ensured that the dredger suction boat is on the center line of the channel during the process of passing through the narrow channel, so as to stay away from obstacles on both sides of the channel and effectively avoid collision accidents. By repeatedly repeating the steps of positioning the steel piles under the dredger suction boat, positioning the steel piles after the grab boat is shifted, and towing the dredger, the dredger suction boat can pass smoothly through the narrow channel, thereby improving the feasibility and safety of the dredger suction boat operating through the narrow channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the dimensions of the dredger suction boat and the navigation channel of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the grab boat in the present invention from a top view;

[0018] Figure 3 It is a schematic diagram of the state before passing through the steps of the present invention;

[0019] Figure 4 It is a schematic diagram of a first state in the steps of the present invention;

[0020] Figure 5 It is a schematic diagram of a second state in the steps of the present invention;

[0021] Figure 6 It is a schematic diagram of the state after passing through the steps of the present invention. DETAILED DESCRIPTION

[0022] In order to further understand the content, features and effects of the present invention, the following embodiments are given to explain in detail.

[0023] Figure 1 and Figure 2 The dimensions of the cutter suction ship, grab ship and navigation channel are given in the figure. It can be seen that: let a be the vertical distance from the mooring pile at the stern of the cutter suction ship to the centerline of the hull; b be the distance between the front and rear mooring holes of the grab ship; e be the length of the channel; and L be the axial length from the stern of the cutter suction ship to the cutter head. Figure 2The structural features of the grab boat can be seen from the figure: the grab boat is equipped with two sets of positioning devices, one is steel pile positioning (including the positioning steel pile located in the middle and the positioning steel piles located on both sides of the stern), and three steel piles are used to fix the ship's position; the other is anchor cable positioning, and two positioning anchors, positioning anchor cables and anchor cable winches are arranged on the left and right sides of the grab boat's hull. The two positioning anchor cables on each side extend out from the cable outlet holes at the front and rear of the hull respectively, and positioning anchors are installed at the ends of the positioning anchor cables.

[0024] See also Figures 3 to 6 It can be seen that the method of the grab boat assisting the cutter suction boat to pass through a narrow channel of the present invention comprises the following steps:

[0025] Step S1, adjust the stern of the dredging vessel toward the channel, move the vessel with the assistance of the auxiliary ship and slowly approach the channel, keep the centerline of the hull of the dredging vessel on the centerline of the channel, when the vertical distance from the center of the three cable columns at the stern to the entrance of the channel is d1, the dredging vessel stops moving and lowers steel piles to maintain the ship's position, and the two transverse anchors at the bow are dropped and the two transverse cables are tightened to complete the anchor braking;

[0026] Step S2, with the assistance of the auxiliary ship, the grab ship slowly approaches the channel exit, adjusts the direction of the grab ship, makes the grab ship hull arranged transversely at the channel exit, makes the center axis of the grab ship hull perpendicular to the center axis of the hull of the cutter suction ship, and makes the distance between the stern of the cutter suction ship and the side of the grab ship be L1, positions the steel piles of the grab ship, lowers the two far-side positioning anchors on the grab ship away from the cutter suction ship into an eight-shaped anchor (that is, anchors in the form of an "eight"), removes the two near-side positioning anchors on the grab ship close to the cutter suction ship, and connects the two removed anchor cable heads to the mooring piles at the stern of the cutter suction ship in a cross state, and tightens the four positioning anchor cables on the grab ship;

[0027] In order to strengthen the control of the lateral displacement and movement of the stern of the cutter suction vessel, the angle between the near-side anchor cable of the grab ship and the centerline of the hull of the cutter suction vessel is greater than 30°; therefore, in this step S2,

[0028] Step S3, the auxiliary ship drives away from the cutter suction ship and stands by in the nearby waters, the cutter suction ship lifts the steel pile, the near-side anchor cable winch of the grab ship reels in the cable, and the transverse winch of the cutter suction ship releases the cable synchronously, keeping all cables in a taut state, and the cutter suction ship slowly moves into the channel. When the distance between the stern of the cutter suction ship and the side of the grab ship is L2, the grab ship stops reeling in the cable, the cutter suction ship stops releasing the cable, and the steel pile under the cutter suction ship is positioned;

[0029] Assuming that the safety distance between the stern of the cutter suction dredge and the grab ship is 2a, then in this step S3, L2=2a.

[0030] Step S4, the grab ship lifts the steel pile, the far side anchor cable winch of the grab ship reels in the cable, and the near side anchor cable is released synchronously, keeping the four positioning anchor cables in a taut state, and the grab ship slowly moves away from the cutter suction ship. When the distance between the stern of the cutter suction ship and the side of the grab ship is L1, the grab ship stops moving, and the steel pile under the grab ship is positioned;

[0031] Step S5, repeating steps S3 and S4 until the hull of the dredging vessel completely drives out of the channel exit, and the safe distance between the dredging head and the channel exit is d2.

[0032] The operation of step S3 and step S4 is called a step, and the travel distance of a single step is The total travel distance of the cutter suction dredger is L+e+d1+d2, and the required number of steps n is expressed as:

[0033]

[0034] A specific embodiment is given below to further illustrate the method of the present invention for a grab boat to assist a cutter suction boat to pass through a narrow channel.

[0035] A coral reef is an annular reef with a lagoon inside. The surface soil of the seabed in the lagoon is coral sand. A dredging and filling project plans to use a suction dredger to take sand from the lagoon and fill it on the reef to form land. The annular reef has a 55m wide mouth, and the mouth channel is 20m long. The water depth at the mouth channel meets the draft requirements of the suction dredger. The suction dredger is 20m wide, the axial length from the stern of the suction dredger to the cutter head is 110m, and the vertical distance from the stern of the suction dredger to the centerline of the hull is 8m. A grab ship is also invested in the project. The grab ship is equipped with a steel pile positioning and anchor cable positioning system. The distance between the front and rear cable outlets of the grab ship is 46m. Due to the narrow mouth channel and complex sea conditions such as water flow and waves, the suction dredger cannot use auxiliary ships to assist in navigation.

[0036] Using this method, the relevant calculation parameters are as follows:

[0037] The vertical distance from the stern mooring pile of the dredging vessel to the centerline of the hull is a=8m; the axial length from the stern of the dredging vessel to the cutter head is L=110m; the length of the navigation channel is e=20m; the distance between the front and rear cable outlet holes of the grab ship is b=46m; the vertical safety distance from the stern to the entrance of the gate channel during the initial positioning of the dredging vessel is d1=10m; the vertical safety distance from the cutter head of the dredging vessel to the exit of the gate channel is d2=10m.

[0038] but:

[0039]

[0040] L2=2a=16m

[0041]

[0042] The total travel distance of the cutter suction boat is L+e+d1+d2=110+20+10+10=150m, so the required number of steps is expressed as: Take the step number as 4.

Claims

1. A method for a grab boat to assist a cutter suction boat to pass through a narrow channel, characterized in that: The following steps are included: Step S1, adjust the stern of the dredging vessel toward the channel, move the vessel with the assistance of the auxiliary ship and slowly approach the channel, keep the centerline of the hull of the dredging vessel on the centerline of the channel, when the vertical distance from the center of the three cable columns at the stern to the entrance of the channel is d1, the dredging vessel stops moving and lowers steel piles to maintain the ship's position, and the two transverse anchors at the bow are dropped and the two transverse cables are tightened to complete the anchor braking; Step S2, with the assistance of the auxiliary ship, the grab ship slowly approaches the channel exit, adjusts the direction of the grab ship, makes the grab ship hull arranged transversely at the channel exit, the center axis of the grab ship hull is perpendicular to the center axis of the cutter suction ship hull, and makes the distance between the stern of the cutter suction ship and the side of the grab ship be L1, positions the steel piles under the grab ship, lowers the two far-side positioning anchors on the grab ship away from the cutter suction ship, removes the two near-side positioning anchors on the grab ship close to the cutter suction ship, and connects the two removed anchor cable heads to the mooring piles at the stern of the cutter suction ship in a cross state, and tightens the four positioning anchor cables on the grab ship; Step S3, the auxiliary ship drives away from the cutter suction ship and stands by in the nearby waters, the cutter suction ship lifts the steel pile, the near-side anchor cable winch of the grab ship reels in the cable, and the transverse winch of the cutter suction ship releases the cable synchronously, keeping all cables in a taut state, and the cutter suction ship slowly moves into the channel. When the distance between the stern of the cutter suction ship and the side of the grab ship is L2, the grab ship stops reeling in the cable, the cutter suction ship stops releasing the cable, and the steel pile under the cutter suction ship is positioned; Step S4, the grab ship lifts the steel pile, the far side anchor cable winch of the grab ship reels in the cable, and the near side anchor cable is released synchronously, keeping the four positioning anchor cables in a taut state, and the grab ship slowly moves away from the cutter suction ship. When the distance between the stern of the cutter suction ship and the side of the grab ship is L1, the grab ship stops moving, and the steel pile under the grab ship is positioned; Step S5, repeating steps S3 and S4 until the hull of the dredging vessel completely drives out of the channel exit, and the safe distance between the dredging head and the channel exit is d2.

2. The method for a grab boat to assist a cutter suction boat to pass through a narrow channel as claimed in claim 1, characterized in that: Let a be the vertical distance from the mooring pile at the stern of the cutter suction ship to the centerline of the hull; b be the distance between the front and rear cable outlet holes of the grab ship; e be the length of the channel; L be the axial length from the stern of the cutter suction ship to the cutter head; the angle between the near-side anchor cable of the grab ship and the centerline of the hull of the cutter suction ship is greater than 30°; then in step S2, 3. The method for a grab boat to assist a cutter suction boat to pass through a narrow channel as claimed in claim 2, characterized in that: The safe distance between the stern of the cutter suction dredge and the grab ship is 2a, so in step S3, L2=2a.

4. The method for a grab boat to assist a cutter suction boat to pass through a narrow channel as claimed in claim 3, characterized in that: The operation of step S3 and step S4 is called a step, and the travel distance of a single step is The total travel distance of the cutter suction dredger is L+e+d1+d2, and the required number of steps n is expressed as:

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