CN111733912A - Underwater trencher with multiple stranding cages and step structure arrangement - Google Patents

Abstract

The invention belongs to the field of underwater pipeline trenching construction, and particularly relates to an underwater trencher with multiple stranding cages and a ladder structure. The invention provides a novel cutter suction type trencher with multiple stranding cages at two sides and a step type combination, which is suitable for harder soil and is an underwater trencher with multiple stranding cages and step type structure arrangement with simple structure and high operation efficiency.

Description

Underwater trencher with multiple stranding cages and step structure arrangement

Technical Field

The invention belongs to the field of underwater pipeline trenching construction, and particularly relates to an underwater trencher with multiple stranding cages and a ladder structure.

Background

The prior art and the defects are as follows:

the transport of offshore oil or gas often employs a subsea pipeline transport process. The submarine pipelines are long in distance and large in pipe diameter (about 1m in diameter), and the pipelines are buried under the seabed, so that underwater special trenching equipment is needed. The general construction method is to lay the pipeline first, then place the trenching equipment, dig the trench along the pipeline and sink the pipe. There are various methods for trenching underwater pipelines, and a high pressure water jet trenching apparatus (see fig. 4) is exemplified as the method for trenching underwater pipelines with reference to fig. 1 (in fig. 1, a cutter suction trencher is replaced with a high pressure water trencher).

The construction method comprises the following steps:

preparing operation: the working mother ship (1-1) puts the high-pressure water trencher (1-3) into water from a deck through a tail crane (1-2), rides on a pipeline paved on the ground in advance under the guidance of a diver, and the front centering device and the rear centering device (4-1 and 4-5) are buckled and clamped on the pipeline paved in advance. At the moment, the supporting sliding shoes (4-11) fall on the underwater ground, the crane is not unhooked, the weight of the trencher under water is shared with the supporting sliding shoes according to the design requirement, and the supporting sliding shoes play a role in keeping the attitude of the trencher. The hydraulic power and electric power supply of the trencher, the control signal and the information feedback signal are connected with the trencher through an umbilical cable of a working mother ship, and an umbilical cable winch (1-4) is used for retracting and releasing the umbilical cable along with the trencher.

And (3) starting operation: and starting the water pump (4-4) to supply the water to a plurality of rows of high-pressure water nozzles arranged on the main spraying arm (4-10), and spraying the water with high pressure to cut the soil. In addition, the auxiliary spraying and flushing system (4-2) also sprays water for operation and is specially used for opening a small ditch of the front centering device. The water pump simultaneously supplies water to a Venturi structure in the mud pumping arm (4-7), so that the suction arm (4-6) generates a strong suction effect to pump out mud. The working mother ship is slowly started to move ahead, the trencher is dragged to move ahead along the pipeline laying direction by a left and a right steel cable traction winches (1-5) at the front part of the working mother ship, and the front and the rear centering devices are provided with contact sensors and guide the left and the right steel cable traction winches to adjust the advancing direction of the trencher; meanwhile, the main spray arm (4-10) is controlled by a main spray arm amplitude-variable oil cylinder (4-9) to slowly swing and sink until the required trenching depth is reached; following the main spraying and flushing arm, the suction arm (4-6) is controlled by a suction arm amplitude-variable oil cylinder and a connecting rod mechanism (4-8) and slowly swings to sink until the sludge suction port reaches the required depth. The trencher continuously digs the trench and moves forward, and the pre-paved pipeline is suspended by a section of the suspended pipeline under the action of gravity, deforms and sinks, and finally falls into the bottom of the trench.

The main body frame (4-3) of the high-pressure water trencher is a supporting and connecting structure of each component, and a part of the pipe structure can also be used for a high-pressure water passage. The upper floats (4-12) are then used to adjust the position of the centre of gravity of the apparatus under water.

The high-pressure water trencher and the operation mode thereof have simple structure, convenient operation and good operation efficiency, but can only be used for geological conditions of soft mud (the compressive strength of soil is less than 50KPa), when the soil is hard (the compressive strength of the soil is more than 30KPa), high-pressure water is difficult to cut, and the trenching needs to be performed repeatedly, so that the operation efficiency is greatly reduced. When the soil is harder (soil compressive strength >50KPa), the operation is basically impossible.

Foreign countries have several typical devices for trenching harder soil underwater either by sprocket cutting, or by routing, or by coulter trenching, or by a combination of these functions. In comparison, the sprocket-type ditcher is complex in structure and very expensive in price; the operation and control difficulty of the stranding cage milling and digging equipment is high, and the operation efficiency is low; the forming ditch of the common plow type ditching is narrow and is mainly used for cable laying, if the pipeline ditch type is larger, a huge plow type ditching machine is needed, and the traction force of the plow type ditching machine is also required to be huge, even hundreds of tons.

At present, high-pressure water ditches are produced in China, but the high-pressure water ditches cannot be suitable for harder soil. Various devices are arranged abroad, the ditching operation of harder soil can be realized, but the ditching device is suitable for large-scale pipe ditches, a plurality of structures are complex, the control difficulty is high, the selling price is extremely high, and domestic construction enterprises are hardly born.

The difficulty and significance for solving the technical problems are as follows:

therefore, based on the problems, the novel cutter suction type trencher which is provided with the multiple stranding cages on two sides and the step combination is applicable to hard soil, simple in structure and high in operation efficiency, and the underwater trencher arranged in the step structure has important practical significance.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art, and provides a novel cutter suction type trencher with multiple stranding cages on two sides and a step combination, which is suitable for hard soil and has the advantages of simple structure, high operation efficiency and arrangement of the multiple stranding cages and the step structure.

The technical scheme adopted by the invention for solving the technical problems in the prior art is as follows:

the utility model provides a many hanks cage, the underwater trencher that stair structure arranged, many hanks cages, underwater trencher that stair structure arranged include hank cage excavating gear, hank cage excavating gear is including excavating hank cage, install bucket tooth and cutting plate on excavating hank cage, cutting plate rear end connection arc stock guide, the arc that the drive shaft passes through spiral lamina and cutting plate welds integratively, the drive shaft is driven by motor drive, it is equipped with the suction dredge pipeline to excavate hank cage upper end department, the suction dredge pipeline communicates with each other with the mud pipe way, be equipped with "venturi" structure between suction dredge pipeline and the mud pipe way.

The bucket teeth and cutting plates are used for cutting earth, wherein the bucket teeth are more advantageous for cutting hard earth.

The invention can also adopt the following technical scheme:

in the underwater trencher with the multiple stranding cages and the ladder structure, the number of the stranding cage excavating devices is further multiple, and the multiple stranding cage excavating devices on the two sides are arranged in a V shape when viewed from the front end of the underwater trencher.

The stepped arrangement can achieve the size of a deeper trench by the superposition effect, and can also prevent large soil from falling into the bottom of the trench without being cut by a stranding cage.

In the underwater trencher with the multiple stranding cages and the ladder structure, the stranding cage excavating device is further provided with a stranding suction tool amplitude-variable oil cylinder for pushing and pulling amplitude-variable oil through a connecting rod mechanism so as to adjust the trenching depth.

In the underwater trencher with the multi-stranding cage and the ladder structure, the cutting plate is further of a multi-plate structure and extends spirally from bottom to top in an inclined mode, so that the rotary excavating impact force can be reduced, and the underwater trencher is favorable for collecting and conveying excavated materials.

In the underwater trencher with the multiple stranding cages and the ladder structure, the stranding cage excavating devices are further connected to two sides of the main body framework respectively, and the stranding cage excavating devices are pushed and pulled by the stranding suction tool amplitude-changing oil cylinders and the connecting rod mechanisms, so that synchronous swinging amplitude changing of 3 groups of stranding cage trenching working devices on two sides is realized, and trenching depth control can be realized.

And the front end and the rear end of the main body frame are provided with a front centering device and a rear centering device which are used for straddling and centering the pre-paved pipeline.

In foretell many hanks cage, among the ditcher under water that stair structure arranged, it is further, the main body frame both sides are equipped with the support piston shoes, install the compression roller between preceding centering device and the back centering device, the main body frame top is equipped with the float, two sets of mud pumping and discharging mechanisms that closely unite with the hank cage and a set of independent mud pumping and raising device that gos deep into the ditch bottom are installed respectively to the main body frame both sides.

In conclusion, the invention has the following advantages and positive effects:

1. the invention discloses a novel cutter suction type trencher with multiple stranding cages and step combination on the basis of a high-pressure water trencher, the operation process (similar to the high-pressure water trencher) is mature and simple, and the equipment control difficulty is small; the invention has relatively simple structure and moderate cost, and solves the bottleneck of domestic underwater hard soil ditching. With the development of the novel cutter suction type trencher technology, the development of the international market can be realized by the technical characteristics of the novel cutter suction type trencher.

Drawings

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for illustrative purposes only and thus do not limit the scope of the present invention. Furthermore, unless otherwise indicated, the drawings are intended to be illustrative of the structural configurations described herein and are not necessarily drawn to scale.

FIG. 1 is a schematic view of an embodiment of a cutter suction trencher-underwater straddle pipe trenching operation provided by the present invention;

FIG. 2a is a schematic view of a cutter suction trencher configuration provided by an embodiment of the present invention;

FIG. 2b is a schematic front view of a cutter suction trencher provided in accordance with an embodiment of the present invention;

FIG. 2c is a schematic rear view of a cutter suction trencher according to an embodiment of the present invention;

FIG. 3a is a schematic structural view of a winch cage excavating device provided by an embodiment of the present invention;

FIG. 3b is a partial schematic view of the winch cage and its drive, and a mud suction port of the winch cage excavating apparatus according to an embodiment of the present invention;

FIG. 3c is a schematic cross-sectional illustration of a winch of the winch excavation apparatus provided in an embodiment of the present invention;

FIG. 4a is a schematic view of a high pressure water trencher configuration;

FIG. 4b is a front end view of the high pressure water trencher;

figure 4c is a rear end view of the high pressure water trencher.

In the figure:

1-1 of a working mother ship, 1-2 of a crane, 1-3 of a cutter suction type trencher, 1-4 of an umbilical cable winch, 1-5 of a left and right steel cable traction winch;

2-1, a front centering device, 2-2, a main body frame, 2-3, a winch suction tool amplitude-variable oil cylinder and a link mechanism, 2-4, a mud suction arm amplitude-variable oil cylinder, 2-5, a rear centering device, 2-6, winch cage excavating devices I, 2-7, winch cage excavating devices II, 2-8, winch cage excavating devices III, 2-9, supporting sliding shoes, 2-10, a press roller, 2-11, a floater, 2-12, a water pump, 2-13 and a mud suction device;

3-1 parts of bucket teeth, 3-2 parts of cutting plates, 3-3 parts of spiral blade plates, 3-4 parts of driving shafts, 3-5 parts of motor driving devices, 3-6 parts of mud sucking pipelines, 3-7 parts of rotating arm supports, 3-8 parts of rotating shaft hinges, 3-9 parts of 'Venturi' structures, 3-10 parts of mud discharging pipelines, 3-11 parts of arc-shaped material guide plates;

4-1 parts of a front centering device, 4-2 parts of an auxiliary spraying and flushing system, 4-3 parts of a main body frame, 4-4 parts of a water pump, 4-5 parts of a rear centering device, 4-6 parts of a suction arm, 4-7 parts of a mud lifting arm, 4-8 parts of a suction arm amplitude-variable oil cylinder and a connecting rod mechanism, 4-9 parts of a main spraying and flushing arm amplitude-variable oil cylinder, 4-10 parts of a main spraying and flushing arm, 4-11 parts of a supporting sliding shoe, 4-12 parts of a floater.

Detailed Description

The present invention will be specifically described with reference to fig. 1 to 4 c.

The utility model provides a many hanks cage, the underwater trencher that stair structure arranged, many hanks cages, underwater trencher that stair structure arranged include hank cage excavating gear, hank cage excavating gear is including excavating hank cage, install bucket tooth and cutting plate on excavating hank cage, cutting plate rear end connection arc stock guide, the drive shaft welds integratively through spiral lamina and cutting plate and arc stock guide, the drive shaft is driven by motor drive, excavation hank cage upper end department is equipped with the suction dredge pipeline, the suction dredge pipeline communicates with each other with the mud pipe way, be equipped with "venturi" structure between suction dredge pipeline and the mud pipe way.

The bucket teeth and cutting plates are used for cutting earth, wherein the bucket teeth are more advantageous for cutting hard earth.

Still further, it is contemplated in the present invention that the number of the gabion excavating devices is plural, and the double-sided multiple gabion excavating devices are arranged in a "V" shape as viewed from the front end of the trencher.

Seen from the side, the winch cage excavating device is arranged in a step shape, the superposition effect can reach the size of a deeper trench, and the situation that large soil falls into the bottom of the trench without being cut by the winch cage can be avoided.

Furthermore, the winch cage excavating device is considered to be in the invention, and the winch cage excavating device is pushed and pulled to change the amplitude by the winch suction tool amplitude-changing oil cylinder through the connecting rod mechanism so as to adjust the trenching depth.

Furthermore, the cutting plate adopts a multi-plate structure, extends spirally from bottom to top and extends backwards in an inclined mode, impact of rotary cutting can be reduced, and the spiral blade plate structure is additionally arranged on the stranding cage, so that the digging material can be collected and discharged upwards.

Furthermore, the winch cage excavating device is connected to two sides of the main body frame, a front centering device and a rear centering device are arranged at the front end and the rear end of the main body frame, and the winch cage excavating device is pushed and pulled by the winch suction tool amplitude-changing oil cylinder and the connecting rod mechanism, so that synchronous swinging amplitude changing of 3 groups of winch cage trenching working devices on two sides is realized, and trenching depth control is realized.

It should be noted that the main body frame both sides are equipped with the support piston shoes, install the compression roller between preceding centering device and the back centering device, the main body frame top is equipped with the float, main body frame both sides are installed respectively two sets of mud pumping and discharging mechanisms that closely unite with the hank cage and a set of independent mud device that pumps deep into at the bottom of the ditch.

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:

the first embodiment is as follows:

description of the structure of the novel cutter suction type trencher:

1. the structure form is formed by combining and arranging a plurality of winch cage excavating devices. As shown in fig. 2: in order to realize the ditching under the pre-laid pipeline, the ditching working devices (2-6, 7 and 8) are symmetrically arranged in a V shape when viewed from the cross section; seen from the side, the ditching working device adopts a combined structure of 3 groups of stranding cage excavating devices, the step-shaped arrangement is realized, the superposition effect can reach the deeper ditching size, and the situation that large soil falls into the bottom of a ditch without being cut by the stranding cage can be avoided.

The twisting cage ditching device is fixed on the main body frame (2-2), and the twisting cage (comprising a driving device), the mud suction pipeline (3-6), the Venturi structure (3-9) and the mud discharge pipeline (3-10) are connected into a whole by the rotating arm support (3-7) and can swing around the rotating shaft hinge (3-8). 3 hank cage excavating gear that the ladder-shaped was arranged on unilateral form integrated configuration, and the frock luffing cylinder of hank suction and link mechanism (2-3) push-and-pull realize 3 groups of hank cage ditching equipment swing luffing synchronously, can realize the control of ditching degree of depth.

2. The structure design of the winch excavating device. As shown in fig. 3, the stranding cage is substantially vertically arranged as viewed laterally (K-direction); slightly outwardly biased as seen in cross-section (see fig. 2 b); the trencher moves longitudinally, and the stranding cage rotates to cut and dredge transversely. The cutting plate (3-2) of the stranding cage adopts a multi-plate structure (3 plates in the figure), extends spirally from bottom to top and extends backwards in an inclined mode, and impact of rotary cutting can be reduced. When the soil is hard, bucket teeth (3-1) can be additionally arranged at the front end of the cutting plate, so that the cutting force is reduced. The arc-shaped material guide plates (3-11) are connected to the rear ends of the cutting plates and are arranged in a circular ring mode (refer to fig. 3c), and the function of collecting and cutting slurry is achieved. The driving shaft (3-4) is welded with the cutting plate and the arc-shaped material guide plate into a whole through the spiral blade plate (3-3), and the spiral blade plate can support the cutting plate, transmit cutting torque and have the function of conveying slurry upwards. As mentioned above, the structure design of the winch cage excavating device can realize the comprehensive effect of cutting and dredging mud and gathering and conveying mud.

3. The combined structure of the dredging and stranding cage and the mud pumping and discharging device. As shown in figure 2, according to the structural arrangement of the trenching working device, the rear 2 groups of the winch excavating devices (2-6 and 2-7) are relatively deep, and in order to improve the efficiency of slurry pumping, as shown in figure 3, a slurry pumping and discharging device is arranged to be tightly combined with the excavating winch, a pumping port is directly aligned to the upper part (rear semicircle) of the winch, and the slurry pushed by the winch can be directly pumped and discharged to the ground at the two sides of the trencher. The front row of the dredging and stranding cages (2-8) is the shallowest, and can directly push a part of mud to the ditch edge while dredging. The rest mud is pumped out of the ditch bottom by the last mud pumping device (2-13), and the ditching operation can be finished.

The working process is as follows:

preparing operation: the working mother ship puts the trencher into water from a deck through a tail crane, aligns front and rear centering devices of the trencher on the underwater pipeline under the guidance of a diver, and slowly falls and straddles the pipeline (a press roll is not basically contacted with the pipeline). At the moment, the supporting sliding shoes (2-9) fall on the underwater ground, but the crane is not unhooked, the weight of the trencher under water is shared with the supporting sliding shoes according to the design requirement, and the supporting sliding shoes play a role in keeping the operation posture of the trencher. The hydraulic power and the electric power of the trencher are supplied, and the control signal and the information feedback signal are connected with the trencher through an umbilical cable of the working mother ship, and the umbilical cable winch is used for winding and unwinding the umbilical cable along with the lifting of the trencher.

And (3) starting operation: sequentially starting the water pumps (2-12) and the winch cage excavating devices (a plurality of groups); the working mother ship starts to start to move forwards slowly, and pulls the trencher to move forwards along the pipeline laying direction by pulling the winch through the left and right steel cables at the bow. Meanwhile, the luffing oil cylinder of the winch suction tool is slowly pushed out, and the multiple groups of winch cage excavating devices swing and sink until the winch cage excavating reaches the required trenching depth; and following the variable-amplitude oil cylinder of the cutter suction tool, the variable-amplitude oil cylinder (2-4) of the mud suction arm is slowly pushed out until the mud suction port of the mud suction and raising device reaches the required depth. Thus, a ditch shape with gradually dug depth is formed until reaching the design depth; the trencher continuously digs the trench and moves forward, and the pre-paved pipeline is suspended by a section of the suspended pipeline under the action of gravity, deforms and sinks, and finally falls into the bottom of the trench.

The working mother ship has a DP positioning function and can drag the trencher to move forwards slowly and accurately along the direction of the pre-laid pipeline. The front centering device, the rear centering device and the opposite compression rollers (2-10) are provided with pipeline contact sensors, when the centering device is in unilateral contact with a pre-laid pipeline and is stressed greatly, the left and right steel cable traction winches retract (or release) the steel cable on one side, the advancing direction of the trencher can be adjusted slightly, and the pipeline cannot be damaged; when the pressure roller is stressed greatly, the height of the lifting hook is slightly adjusted by the crane, and the pipeline is guaranteed not to be damaged by pressure.

1. The novel cutter suction type trencher is in a structural form of combined arrangement of 3 groups of stranding cage excavating devices on two sides. During the ditching operation (see fig. 2), the ditching working devices are symmetrically arranged in a V shape from the cross section, so that the ditching under the pre-laid pipeline can be realized; seen from the side, the ditching working device adopts the step-shaped arrangement of a plurality of groups of stranding cage excavating devices, and the superposition effect can reach the deeper ditching size. The stepped stranding cage arrangement ensures that the soil of the small V-shaped part which can not be directly cut in the middle part can not directly fall to the bottom of the ditch after the soil collapses, but can be stranded and cut through the stranding cage on the lower layer of the slope, thereby avoiding that the large soil directly falls to the bottom of the ditch to influence the depth of ditching. 3 hank cage excavating gear that stairstepping was arranged in both sides forms an organic whole through link mechanism, is pushed and pulled by the width of cloth hydro-cylinder of hank suction frock, and synchronous swing realizes the control of ditching degree of depth. The actual trenching immersed tube effect can be monitored in real time through a sonar device, and the trenching depth can be adjusted through a cutter suction tool variable-amplitude oil cylinder (comprising a mud suction arm variable-amplitude oil cylinder).

2. The structure of the winch cage excavating device is shown in figure 3, and the winch cage rotates to cut soil and is a key part of the winch cage excavating device. The design of the cutting part of the stranding cage is a structure with replaceable bucket teeth, on one hand, the easily-worn parts can be replaced, and on the other hand, the bucket teeth can be arranged in an encrypted manner according to soil conditions (when the soil is hard); or the bucket teeth (applicable to sandy soil) are removed, and the cutting blade plate is used for direct cutting operation. The twisting cage is provided with a spiral blade plate which is connected with the driving shaft and the cutting plate and used for transmitting torque; meanwhile, when the stranding cage rotates for cutting, the spiral blade plate has the function of lifting mud, and the subsequent mud sucking and discharging mechanism is assisted to work. The design of parameters such as the structure size, the rotating speed and the like of the stranding cage is closely related to the soil characteristics, the advancing speed and the like, and the trenching effect is directly influenced.

3. And the integrated design of dredging and pumping sludge discharge. The whole process of trenching can be finished only by digging soil with the stranding cage digging device and stirring the soil into slurry in water and pumping the slurry out of the bottom of the trench. And 2 groups of sludge pumping and discharging mechanisms closely combined with the winch cages and a group of independent sludge pumping and discharging devices (see figures 2 and 3) penetrating into the bottom of the ditch are respectively adopted by the design matched with the trenching capacity of 3 groups of winch cage excavating devices on two sides, so that the sludge pumping and discharging effect is greatly improved. The group of winch cage excavating devices on the shallowest layer can also push and discharge partial slurry to the outer side edge of the ditch through the structure lifting action of the helical blades in the winch cage; the second and third layer of the winch cage excavating devices are directly provided with a mud sucking port above (at the rear side of) the winch cage, and mud is discharged to the outside of the supporting skid shoe of the trencher by the suction force generated by a Venturi structure in a pipeline; especially, the arrangement of the half-moon-shaped suction ports adopts a bypass to suck mud, so that the driving device of the stranding cage is prevented from being abraded, and the reliability of the driving device is improved. And part of the slurry remained at the bottom of the ditch is discharged out of the ditch by the last sludge suction and raising device. The structure of the invention is shown in figure 3, the combination design of the stranding cage and the mud sucking and discharging mechanism can improve the mud sucking and discharging efficiency, simplify the structure and reduce the size of the equipment.

In conclusion, the invention can provide the novel cutter suction type trencher which is provided with the two sides provided with the multiple stranding cages and is combined in a step mode, can adapt to harder soil, and has the advantages of simple structure and higher operation efficiency.

The present invention has been described in detail with reference to the above examples, but the description is only for the preferred examples of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.

Claims (6)

1. The utility model provides a many hanks cage, underwater trencher that stair structure arranged which characterized in that: many hank cages, the underwater trencher that stair structure arranged include hank cage excavating gear, hank cage excavating gear is including excavating the hank cage, install bucket tooth and cutting plate on excavating the hank cage, cutting plate rear end termination arc stock guide, the drive shaft welds integratively through the arc of spiral lamina and cutting plate, the drive shaft is driven by motor drive, it is equipped with the mud suction pipe way to excavate hank cage upper end department, the mud suction pipe way communicates with each other with the mud discharge pipe way, be equipped with "venturi" structure between mud suction pipe way and the mud discharge pipe way.

2. The multi-stranding cage, ladder construction arrangement underwater trencher as defined in claim 1 wherein: the number of the winch cage excavating devices is multiple, and the multiple winch cage excavating devices on the two sides are arranged in a V shape when seen from the front end of the underwater trencher.

3. The multi-stranding cage, ladder construction arrangement underwater trencher as defined in claim 1 wherein: the winch cage excavating device is pushed and pulled to change the amplitude by an amplitude-changing oil cylinder of the winch suction tool through a connecting rod mechanism.

4. The multi-stranding cage, ladder construction arrangement underwater trencher as defined in claim 1 wherein: the cutting plate adopts a multi-piece structure and extends spirally from bottom to top backwards in an inclined mode.

5. The multi-stranding cage, ladder construction arrangement underwater trencher as defined in claim 1 wherein: the winch cage excavating device is installed on the main body framework, a front centering device and a rear centering device are arranged on the front side and the rear side of the main body framework, and the winch cage excavating device is pushed and pulled by a winch suction tool amplitude-changing oil cylinder and a connecting rod mechanism.

6. The multi-stranding cage, ladder construction arrangement underwater trencher as defined in claim 1 wherein: the main body frame both sides are equipped with the support piston shoes, install the compression roller between preceding centering device and the back centering device, the main body frame top is equipped with the float, install two sets of pumping row's mud mechanism and a set of independent suction that gos deep into at the bottom of the ditch that closely unite with the hank cage on the main body frame and raise mud device.

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