Work system and method for trenching and cable laying using underwater jets

Abstract

The present invention belongs to the technical field of underwater work, and more specifically, relates to a work system and method for trenching and cable laying using underwater jets. The underwater traveling device is installed at the lower end of the system body, two jet arms are located at the front end of the system body, and a jet suction device is installed at the rear end of the system body and includes a suction conduit and a second jet pipe. The suction conduit is used to suck up mud and sand from inside the trench through the suction port and discharge the mud and sand to the outside of the trench through the discharge port before the cable sinks to the bottom of the trench. The second jet pipe maintains the trench shape as the cable sinks to the bottom of the trench by ejecting a horizontal jet stream of water to clean the inner walls and bottom of the trench along the length of the trench. The present invention can be applied to situations where the bending radius of the cable is large and the cable has no choice but to sink naturally on a soft seabed, and it is necessary to ensure that the cable is laid to a target depth and that work requirements are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater operations, and specifically relates to a working system and a working method for trench cutting and cable laying by underwater jets.

Background Art

[0002] Currently, in the installation of submarine cables, since it is necessary to bury the cable on the seabed, the working process is more complicated. An underwater working system is used to move along the direction of the cable previously laid on the seabed, and a trench cutting device mounted thereon cuts a trench on the seabed, and the cable is sunk to the bottom of the trench, so as to ensure that the burial depth meets the requirements. For the seabed with soft soil, the trench cutting device is generally trench cutting by jets, that is, trench cutting is performed by ejecting a jet water flow toward the seabed using an injection arm. On the other hand, for a cable with a large bending radius, such as a cable with a large diameter and high surface hardness, since the bendable range is greatly limited, usually, other cable pressing and assisting devices cannot be used during laying, and it is necessary to ensure that the cable sinks to the bottom of the trench naturally so that the cable will not be crushed during laying. However, when relying on the natural sinking of the cable, since the laying position of the cable is generally in the deep sea, the buoyancy in water received is large and the natural sinking speed is slower. Especially in the case of a cable with a large bending radius or a large trench depth, the distance for the cable to completely sink from the seabed to the bottom of the trench is large. On the seabed with high softness of soil, the sediment on the seabed is easily filled back naturally by the ocean current, and both sides of the trench are likely to collapse and slide down and be filled back to the bottom of the trench. As a result, a problem occurs that the depth of the trench becomes shallow before the cable completely sinks to the bottom of the trench, and the final burial depth of the cable cannot meet the standard.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The technical problem that this invention aims to solve is to provide a work system and method for trenching and cable laying using an underwater jet, which can be applied to situations where, in a seabed with soft soil, the bending radius of the cable is large and it can only sink naturally, and the goal is to ensure that the cable is laid to a target depth. [Means for solving the problem]

[0004] The present invention relates to a work system for groove cutting and cable laying using an underwater jet, The system unit and An underwater travel device installed at the lower end of the main system body, A jet-type soil crushing device including two jet arms located at the front end of the main system body, each equipped with a front nozzle for cutting grooves in the seabed by ejecting a jet of water, The system is installed at the rear end of the main body and includes a suction line and a second injection pipe, the suction line having an outlet and a suction port, the suction port being used toward the bottom of the trench, the outlet being positioned higher than the suction port and laterally to the suction port, and the suction line comprises an injection suction device used to suck up mud and sand from the trench through the suction port and discharge the mud and sand to the outside of the trench through the outlet before the cable sinks to the bottom of the trench, The second jet pipe is located behind the suction conduit, and has a nozzle installed in it. The nozzle's spray direction is set horizontally away from the suction conduit. The second jet pipe is used to maintain the shape of the trench as the cable sinks to the bottom of the trench by spraying a horizontal jet of water from the nozzle after the suction conduit has sucked up the mud and sand from the trench, cleaning the inner walls and bottom of the trench along its length. This provides a work system for trench cutting and cable laying using an underwater jet.

[0005] Furthermore, the injection-type soil crushing device further includes a first laying mechanism, the first laying mechanism includes a fixed pipeline, a rotating pipeline, a first drive mechanism and a second drive mechanism, the fixed pipeline being fixed to the system body, the rotating pipeline being rotatably installed on and communicating with the fixed pipeline, the first drive mechanism being used to rotate the rotating pipeline around the fixed pipeline, the two injection arms being rotatably installed on and communicating with the rotating pipeline, and the second drive mechanism being used to rotate the two injection arms around the rotating pipeline.

[0006] Furthermore, the injection-type soil crushing device further includes a third drive mechanism that can adjust the distance between the two injection arms by driving the two injection arms to move along the axial direction of the rotating pipeline.

[0007] Furthermore, two suction lines are installed, spaced apart along the width direction of the system body, and the spacing between the two suction lines is adjustable; two second injection pipes are installed, spaced apart along the width direction of the system body, and the spacing between the two second injection pipes is adjustable.

[0008] Furthermore, the injection suction device further includes a second laying mechanism, a support base, and a first drive assembly, wherein the second laying mechanism is installed at the rear end of the system body, the support base is installed at the end of the second laying mechanism away from the system body, a single second injection tube is fixedly connected to a single suction line, and the single second injection tube and the suction line fixedly connected thereto constitute one injection suction assembly, both injection suction assemblies are installed on the support base, the two injection suction assemblies are installed spaced apart, and a cable can fall into a groove from between the two injection suction assemblies.

[0009] Of the two injection suction assemblies, at least one is slidably mounted on a support base, and the first drive assembly adjusts the distance between the two injection suction assemblies by driving the slidably mounted injection suction assembly to move.

[0010] Furthermore, tail nozzles are installed at the bottom of both injection arms, and the injection direction of the tail nozzles is set to be opposite to that of the injection direction of the front nozzles.

[0011] Furthermore, the installation height of the two injection arms and the two injection suction assemblies is adjustable.

[0012] Furthermore, the suction pipeline has a first water inlet at one end and is installed laterally at the other end, with the outlet located at the laterally installed end, and a pipe diameter reduction section is installed in the suction pipeline between the first water inlet and the outlet, with an extension pipe extending vertically from the side of the pipe diameter reduction section, with the suction port located on the extension pipe, and an end cover is installed at the outlet location in the suction pipeline, and the degree of opening and closing between the end cover and the outlet is adjustable.

[0013] Furthermore, the system is equipped with a front nozzle located at the front end of the main body and in front of the two jet arms, which further provides a front jet mechanism to sweep and / or pre-cut grooves in the seabed before the two jet arms begin work.

[0014] The present invention further provides a method for working with underwater jets for groove cutting and cable laying, and using the above-mentioned underwater jet-based groove cutting and cable laying system, the method is as follows: Step S1 involves dropping a work system for trenching and cable laying using an underwater jet onto the seabed where trenching and cable laying are to be performed, and positioning the projections of the two jet arms on the seabed to correspond to both sides of the cable. The underwater jet-powered furrowing and cable laying work system involves an underwater traveling device that travels along the length of the cable on the seabed, and ejecting jets of water from the front nozzles of two jet arms to break up the seabed soil along the length of the cable and cut a furrow, in step S2. Step S3 includes continuously liquefying the soil in the trench, maintaining the trench shape, and allowing the cable to naturally sink to the bottom of the trench by sucking the mud and sand from the suction port of the suction conduit and discharging the mud and sand to the outside of the trench from the discharge port, and also spraying a horizontal jet of water from the nozzle to wash the inner wall and bottom of the trench along the length of the trench. [Effects of the Invention]

[0015] The beneficial effects of this invention are as follows: In the case of a cable with a large bending radius, the distance over which it completely sinks from the seabed to the bottom of the trench is longer, so the jet suction device is installed on the outside of the rear end of the system body, with a large distance from the two jet arms, which is suitable for the range over which the cable naturally sinks. The underwater traveling device drives the entire working system along the length of the cable on the seabed, and the two jet arms form the trench by ejecting a stream of water to break up the seabed soil and cut a trench. Due to the high softness of the soil, after the soil is crushed and a trench is cut, the trench is prone to collapsing in a short time. By installing a jet suction device at the rear end of the system body, after the trench is cut and before the cable sinks to the bottom of the trench, the mud and sand that has naturally backfilled and the mud and sand that has accumulated at the bottom of the trench as both sides of the trench collapse are extracted from the suction pipe, and the extracted mud and sand are discharged to the outside of the trench, thereby ensuring the depth of the trench. After suction by the suction pipe, a second jet pipe is used to continuously generate a horizontal jet of water along the length of the trench within the trench, cleaning the inner walls and bottom of the trench, continuously liquefying the soil, maintaining the trench shape as the cable sinks to the bottom of the trench, ensuring the depth of the trench, ensuring that the laying depth meets the work requirements, and improving the safety and stability of the cable after it is buried on the seabed.

[0016] In one embodiment, the present invention allows for the discharge of sediment accumulated at the bottom of a trench to both sides of the trench after a trench has been cut by a jet-type soil crushing device and before the cable has completely fallen to the bottom of the trench, and by continuously maintaining the trench shape using two jet nozzles, it ensures that the naturally sinking cable can sink to the bottom of the trench. In another embodiment, the discharged sediment is expelled to the outside of the trench and then refilled into the trench by the action of ocean currents. For large diameter cables and deep trenches, this helps to bury the cable after it has sunk to the bottom of the trench by utilizing the washing action of natural ocean currents, ensuring that the cable is not exposed and improving the reliability of underwater cable burying operations. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic diagram of the first working position of the work system for groove cutting and cable laying using an underwater jet according to the present invention. [Figure 2] Figure 2 is a schematic diagram of the second working position of the work system for groove cutting and cable laying using an underwater jet according to the present invention. [Figure 3] Figure 3 is a schematic diagram of the structure of the underwater mobile device according to the present invention. [Figure 4] Figure 4 is a schematic diagram of the structure of a rotatable propeller in an underwater traveling device according to the present invention. [Figure 5] Figure 5 is a schematic diagram of the structure of the first installation method of the crawler mechanism in the underwater traveling device according to the present invention. [Figure 6] Figure 6 is a schematic diagram of the structure of the second installation method of the crawler mechanism in the underwater traveling device according to the present invention. [Figure 7] Figure 7 is a schematic diagram of the crawler module in the underwater traveling device according to the present invention in a downward-tilted position. [Figure 8] Figure 8 is a schematic diagram of the structure of the injection-type soil crushing device according to the present invention. [Figure 9] Figure 9 is a schematic diagram of the first descent position of the jet-type soil crushing device according to the present invention. [Figure 10] Figure 10 is a left side view of FIG. 9 according to the present invention. [Figure 11] Figure 11 is a schematic view after the distance between the two injection arms in FIG. 9 according to the present invention is increased. [Figure 12] Figure 12 is a schematic view of the second lowered posture of the injection type soil crushing device according to the present invention. [Figure 13] Figure 13 is a schematic view of the returning posture of the injection type soil crushing device according to the present invention. [Figure 14] Figure 14 is a schematic structural view of the front injection mechanism according to the present invention. [Figure 15] Figure 15 is a schematic structural view of the injection suction device according to the present invention when viewed from the first angle. [Figure 16] Figure 16 is a schematic structural view of the injection suction device according to the present invention when viewed from the second angle. [Figure 17] Figure 17 is a schematic view of the returning posture of the injection suction device according to the present invention. [Figure 18] Figure 18 is a schematic view of the lowered posture of the injection suction device according to the present invention. [Figure 19] Figure 19 is a schematic view of the left swinging posture of the injection suction device according to the present invention.

Mode for Carrying Out the Invention

[0018] As shown in FIGS. 1 to 19, the present invention provides a working system for trench cutting and cable laying by an underwater jet, which includes a system main body 1, an underwater traveling device 2, an injection type soil crushing device 3, and an injection suction type cable guiding device 4 which is an injection suction device. The underwater traveling device 2 is installed at the lower end of the system main body 1 and is used to move and drive a working system for trench cutting and cable laying by an underwater jet on the seabed. The injection type soil crushing device 3 includes a first laying mechanism and two injection arms 34. The first laying mechanism is installed on the system main body 1, and the two injection arms 34 are installed on the first laying mechanism, located at the front end of the system main body 1, and front nozzles 3411 for cutting a trench on the seabed by ejecting jet water flows are installed on both of them.

[0019] The injection suction device 4 is installed at the rear end of the system body 1 and includes a suction conduit 42 and a second injection pipe 43. The suction conduit 42 has an outlet 422 and a suction port 423, the suction port 423 is used to direct the suction towards the bottom of the trench, and the outlet 422 is positioned higher than the suction port 423 and laterally relative to the suction port 423. In the operation of cutting a trench and laying a cable, the suction conduit 42 works behind the injection arm and sucks up mud and sand from the trench through the suction port 423 before the cable sinks to the bottom of the trench. It is used to discharge mud and sand from the discharge port 422 to the outside of the trench, thereby ensuring that the trench depth meets the installation requirements. Specifically, the height difference between the discharge port 422 and the suction port 423 is greater than the depth of the trench to be constructed. After the end of the suction pipe with the suction port 423 is inserted into the trench, the discharge port 422 is located on one side of the upper part of the trench. When the suction port 423 sucks up mud and sand from the bottom of the trench, the mud and sand is discharged from one side of the upper part of the trench, thereby ensuring that the mud and sand in the trench is effectively extracted.

[0020] The second injection pipe 43 is located behind the suction pipe 42 and is equipped with an injection nozzle 432. The injection direction of the injection nozzle 432 is set horizontally away from the suction pipe 42. When in use, the end of the second injection pipe 43 equipped with the injection nozzle 432 is inserted into the groove. As the system body 1 moves to cut the groove, the injection nozzle 432 can eject a horizontal jet of water along the length of the groove toward the rear of the system body 1. Thus, the second injection pipe 43 is used to clean the inner walls and bottom of the groove along the length of the groove by ejecting a horizontal jet of water after the suction pipe 42 has sucked up the mud and sand from the groove, thereby continuously liquefying the soil, maintaining the groove shape as the cable sinks to the bottom of the groove, and ensuring that the sinking depth of the cable meets the work requirements when the cable falls to the bottom of the groove. As shown in Figures 1 and 2, for a cable 100 with a large bending radius, the distance it takes to completely sink from the seabed to the bottom of the trench is longer, so the two jet suction assemblies are installed outside the rear end of the system body 1, at a large distance from the two jet arms 34, suitable for the range in which the cable 100 will naturally sink. The underwater traveling device 2 drives the entire working system along the length of the cable 100 on the seabed, and the two jet arms 34 form trenches by jetting water to break up the seabed soil and cut trenches, which can be better applied to seabeds with soft soil compared to mechanical cutting soil breakers. Due to the high softness of the soil, after the soil is crushed and a trench is cut, the trench is prone to collapsing in a short time. By installing a jet suction device 4 at the rear end of the system body 1, after the trench is cut and before the cable sinks to the bottom of the trench, the mud and sand that has naturally backfilled and the mud and sand that has accumulated at the bottom of the trench as both sides of the trench collapse are extracted from the suction pipe 42, and the extracted mud and sand are discharged to the outside of the trench, thereby ensuring the depth of the trench. After suction by the suction pipe 42, a second jet of water is continuously generated in the trench using the second jet pipe 43 along the length of the trench, cleaning the inner walls and bottom of the trench, continuously liquefying the soil, maintaining the trench shape as the cable sinks to the bottom of the trench, ensuring the depth of the trench, ensuring that the laying depth meets the work requirements, and improving the safety and stability of the cable after it is buried on the seabed.In one aspect, the present invention allows for the discharge of mud and sand accumulated at the bottom of the trench to both sides of the trench after a trench has been cut by the jet-type soil crushing device 3 and before the cable has completely fallen to the bottom of the trench, and by continuously maintaining the trench shape using two jet nozzles 432, it ensures that the naturally sinking cable 100 can sink to the bottom of the trench. In another aspect, the suction-discharged mud and sand are discharged to both sides of the trench and then refilled into the trench by the action of ocean currents. Therefore, for cables with a large diameter 100 and trenches with a large depth, the cable 100 can be buried using natural ocean current washing after it has sunk to the bottom of the trench, ensuring that the cable 100 is not exposed and improving the reliability of underwater cable burial work.

[0021] The underwater mobile device includes a mobile mechanism and a propulsion mechanism. The propulsion mechanism is installed on the system body 1 and is used to assist in the movement and attitude adjustment of the underwater mobile device by generating thrust. Two mobile mechanisms are provided, and the two mobile mechanisms are located correspondingly on both sides of the system body 1. That is, one mobile mechanism is located on one side of the system body 1, and the other mobile mechanism is located on the other side of the system body 1, and the mobile mechanisms are connected to the system body 1. In one embodiment of the present invention, as shown in Figure 3, the mobile mechanism is a shoe 21, and the shoe 21 and the system body 1 are fixedly connected. In cooperation with the thrust generated by the propulsion mechanism, the work system is able to glide on the seabed. Compared to a crawler mechanism, the shoe 21 has a simple structure and is lighter in weight, so it can reduce the overall weight of the work system underwater and is suitable for operation on unstable soft ground.

[0022] In another embodiment of the present invention, as shown in Figures 5 to 7, the travel mechanism is a crawler mechanism 22, which is connected to the system body 1 by a hinge connection, and both crawler mechanisms 22 have a travel stroke that is inclined relative to the system body 1, that is, the posture of the two crawler mechanisms 22 on the system body 1 is adjustable. On both sides of the system body 1, corresponding drive mechanisms are installed to adjust the posture of the crawler mechanisms 22 by driving the crawler mechanisms 22 located on both sides of the system body 1, thereby adjusting the degree of inclination of the crawler mechanisms 22 relative to the system body 1 and adjusting the angle formed by the bottoms of the two crawler mechanisms 22.

[0023] The underwater running device according to the present invention is based on an embodiment of the crawler mechanism 22. By adjusting the attitude of the crawler mechanism 22, the inclination of the crawler mechanism 22 with respect to the system body 1 and the angle formed by the bottoms of the two crawler mechanisms 22 can be adjusted. By making the bottom surfaces of the two crawler mechanisms 22 the same horizontal plane, it is suitable for running on gentle seabeds. Alternatively, by making the bottom surfaces of the two crawler mechanisms 22 form an upward or downward angle, it can adapt to seabeds with ridge-like protrusions or groove-like downward depressions. This improves the grip ability of the crawler mechanism 22 on such seabed topography, improving underwater running performance. The propulsion mechanism allows for adjustment of the device's attitude and provides auxiliary thrust. Combined with the thrust of the crawler mechanism 22 itself during operation, this meets the thrust requirements for running on muddy, soft seabeds, avoids slipping, further improves underwater running performance, meets the running requirements and reliability on different underwater terrains, improves the flexibility of underwater work, and expands the range of workable scenarios. Figure 7 shows the state of the two crawler mechanisms 22 after adjusting their posture to adapt to a groove-shaped, downward-sloping seabed. When used to adapt to a seabed with a ridge-like protrusion, the two crawler mechanisms 22 are tilted downward.

[0024] In one installation method of the present invention, as shown in Figure 5, a single crawler mechanism 22 is a single crawler running mechanism, that is, only one crawler running mechanism is installed on one side of the system body 1.

[0025] In the preferred installation method of the present invention, as shown in Figures 6 to 7, a single crawler mechanism 22 includes two crawler modules 221, both of which are hinged to the system body 1 and have a travel stroke that is inclined relative to the system body 21, and a single crawler module 221 is a single crawler running mechanism, that is, two of the above crawler running mechanisms are installed on one side of the system body 21 according to the present invention, and the specific structural principles of the above crawler running mechanisms are the same as in the prior art, so a detailed explanation is omitted here. A single drive mechanism includes two first drive modules 23 for rotationally driving the two crawler modules 221 corresponding to the hinge connection points with the system body 1. In this installation method, a total of four crawler modules 221 are installed on both sides of the system body 1, and each is driven by a corresponding first drive module 23 to adjust its attitude. Therefore, the four crawler modules 221 can have different inclination angles on uneven seabeds, thereby improving grip and enabling easy travel on seabeds with large-grained rocks.

[0026] The crawler module 221 is connected to the system body 1 by connecting rods 24 and works in cooperation with the first drive module 23 to adjust the attitude of the crawler module 221. Compared to a system in which a rotary drive module directly rotates the crawler module 221, using a connecting rod structure contributes to improved load-bearing capacity and reduces the strength requirements of the first drive module 23. Specifically, a single crawler module 221 is connected to the system body 1 by two connecting rods 24. One end of each connecting rod 24 is hinged to the system body 1, and the other end is hinged to the crawler module 221, thereby forming a quadrilateral mechanism. Since two connecting rods 24 are connected to a single crawler module 221 and the system body 1, it helps to improve structural strength and also distributes the load. For the same load-bearing capacity, the load on a single connecting rod 24 is smaller, and the strength and dimensional requirements of the connecting rod 24 are lower. The first drive module 23 is a linear drive module, such as a hydraulic cylinder or another drive module that is a linear output, wherein the hydraulic cylinder is hinged to the system body 21 on the cylinder body side and hinged to one of the connecting rods on the piston side.

[0027] The propulsion mechanism includes a vertical propeller 25 and a horizontal propeller 26, both of which are installed on the system body 1. As shown in Figure 3, the vertical propeller 25 is a propeller installed along the vertical direction of the system body 1 and is used to assist in lifting and lowering the work system by generating vertical thrust, while the horizontal propeller 26 is a propeller positioned along the horizontal direction of the system body 1 and is used to provide auxiliary thrust to the work system for forward / backward and lateral movement by generating horizontal thrust for the work system in the forward / backward or lateral direction, thereby improving the flexibility of underwater work.

[0028] The propulsion mechanism further includes a rotatable propeller 27, which is installed on the system body 1 and has a travel stroke inclined relative to the system body 1, thereby adjusting the direction of thrust by adjusting the inclination of the rotatable propeller 27. For example, in the case of soft muddy or complex seabed terrain where the existing thrust of the work system is insufficient for travel, additional horizontal or vertical thrust is generated in addition to the thrust of the existing vertical propeller 25 or horizontal propeller 26. This increases the horizontal or vertical thrust, thereby enabling travel of the work system. Because the thrust direction of the rotatable propeller 27 is adjustable, a single rotatable propeller 27 can be used to increase the vertical thrust of the work system or to increase the horizontal thrust of the device, offering high flexibility in use. If the propeller output is the same and the maximum vertical thrust and maximum horizontal thrust of the work system are the same, the total number of propellers can also be reduced. The present invention further comprises a second drive module 28, wherein the rotatable propeller 27 includes a connecting rod 271 and a propeller body 272 fixedly mounted on the connecting rod 271, the propeller body 272 moving and rotating in accordance with the connecting rod 271, the connecting rod 271 being mounted on the system body 1 by hinge connection and having a rotational stroke relative to the system body 1, and the second drive module 28 is used to adjust the inclination of the rotatable propeller 27 relative to the system body 1 by rotationally driving the connecting rod 271, thereby adjusting the inclination of the rotatable propeller 28. Specifically, the second drive module 28 is a hydraulic cylinder or another drive module which is a linear output, the hydraulic cylinder having its cylinder body side hinged to the system body 21 and its piston side hinged to the side of the connecting rod 271, and when the piston side of the hydraulic cylinder extends, it rotationally drives the connecting rod 271. The structural principles of the vertical propeller, horizontal propeller, and propeller body described above are all the same as those of conventional propellers, and therefore a detailed explanation is omitted here.

[0029] In this invention, a cable detection module is further installed, which is mounted on the system body 1, located at the foremost end of the work system, and has two sets of mounting interfaces at different heights. The cable detection module frame has a two-stage hydraulic cylinder, the first stage hydraulic cylinder rotates the frame of the cable detection module, and the second stage hydraulic cylinder changes the height of the cable detection module, ultimately achieving four levels of laying height for the cable detection module, adapting to the detection of cables of different geological conditions and diameters. Specifically, the cable detection module is a sensor utilizing an electromagnetic induction cable, which is electrically connected to the control system of the work system and is used to sense the position of the cable and transmit the position information to the control system of the work system. The control system, through judgment and calculation, automatically controls the propulsion mechanism and the travel mechanism, and adjusts the direction and speed of the entire work system, so that the work system can automatically follow the length of the cable, cut a groove and lay the cable, reducing active intervention by the operator and making the groove cutting and cable laying process smarter. Laying as described herein is the lowering of the target mechanism to the working position.

[0030] The first laying mechanism includes a fixed conduit 31, a rotating conduit 32, a first drive mechanism 33, and a second drive mechanism 36. The fixed conduit 31 is attached to the system body, and the rotating conduit 32 is rotatably installed on the fixed conduit 31 and communicates with the fixed conduit 31. That is, the rotating conduit 32 has a stroke that rotates radially relative to the fixed conduit 31 and maintains communication with the fixed conduit 31 even after rotation. The first drive mechanism 33 is used to rotate the rotating conduit 32 around the fixed conduit 31. The first drive mechanism 33 is a hydraulic cylinder, the piston side of which is hinged to the rotating conduit 32, and the cylinder body side is hinged to the system body, forming a connecting rod-like structure, thereby enabling rotation of the rotating conduit 32 and also increasing its load-bearing capacity. A flow guide member 35 is fixedly installed at the water supply end of each of the two injection arms 34, and each injection arm 34 is in communication with its corresponding flow guide member 35. Both flow guide members 35 are rotatably installed in the rotating pipe 32 and are in communication with the rotating pipe 32. That is, the two flow guide members 35 have a stroke that rotates radially with respect to the rotating pipe 32 and maintain communication with the rotating pipe 32 even after rotation, and furthermore, the two injection arms 34 are maintained in communication with the rotating pipe 32. The second drive mechanism 36 is used to rotate the two injection arms 34 and the two flow guide members 35 around the rotating pipeline 32. The number of second drive mechanisms 36 corresponds to the number of flow guide members 35, and may be two. The second drive mechanism 36 is a hydraulic cylinder, the piston side of which is hinged to the flow guide member 35 and the cylinder body side is hinged to the system body, forming a connecting rod-like structure, thereby enabling the rotation of the two flow guide members 35 and the two injection arms 34, and also increasing the load-bearing capacity.

[0031] In the injection-type soil crushing device according to the present invention, the fixed conduit 31 and the rotating conduit 32 are used not only as water supply conduits for the two injection arms 34, but also as mounting and support structures for the two injection arms 34. In realizing the mounting of the two injection arms 34, there is no need to install additional piping corresponding to the descent depth to connect the two injection arms 34 and the pump mechanism. Even if the descent depths of the injection arms 34 are different, communication with the injection arms 34 can be ensured, which helps to simplify the overall structure, reduce the overall volume, and reduce the occupied space. Compared to ordinary piping, the fixed conduit 31 and the rotating conduit 32 are used as mounting and support structures for the two injection arms 34, so their strength and hardness are higher, and even when used as water supply conduits, water leakage due to impact from seabed organisms or rocks is less likely to occur, resulting in higher reliability. By forming a two-stage drive structure using the first drive mechanism 33 and the second drive mechanism 36, it is possible to lower and return the two injection arms 34. Furthermore, when the lowering of the two injection arms 34 is achieved by reversing the rotational pipeline 32 using the first drive mechanism 33, the second drive mechanism 36 can also adjust the posture by synchronously rotating the two injection arms 34. When the two injection arms 34 are lowered to a deeper or shallower depth, the angle of the front nozzle with respect to the vertical is maintained within the range of the optimal injection angle, ensuring that the injection angle of the water jet is the optimal injection and soil crushing angle. Thus, the present invention can be adapted to ditching work at different depths, while also ensuring the quality and efficiency of ditching and providing high flexibility for underwater work.

[0032] Figure 9 shows the position after the two injection arms 34 have fully descended, i.e., the position at their lowest point, which is suitable for grooving deeper grooves, and Figure 10 shows the position when the two injection arms 34 have descended to a shallower depth, which is suitable for grooving shallower grooves. In both positions, the orientation of the front nozzle and its angle with respect to the vertical are the same.

[0033] In one embodiment of the present invention, a fixed conduit 31 and a rotating conduit 32 are connected by flexible piping, and communication is ensured to accommodate the rotational stroke of the rotating conduit 32. The rotating conduit 32 is connected to two flow guide members 35 by flexible piping, and communication is ensured to accommodate the movement stroke of the two flow guide members 35.

[0034] In a preferred embodiment of the present invention, a radial dynamic seal is installed at the rotational engagement point between the rotating pipe 32 and the fixed pipe 31, allowing the rotating pipe 32 and the fixed pipe 31 to communicate directly in order to accommodate the rotational stroke. A radial dynamic seal is also installed at the rotational engagement point between the two flow guide members 35 and the rotating pipe 32, allowing the two flow guide members 35 and the rotating pipe 32 to communicate directly in order to accommodate the rotational stroke. In this embodiment, there is no need to install additional flexible piping, reducing the complexity of the pipeline and the risk of damage or water leakage at the communication points.

[0035] Two sets of fixed conduits 31 are installed, and one set of pump mechanisms 38 is connected to each of the two sets of fixed conduits 31, that is, the two sets of fixed conduits 31 provide water supply through their respective corresponding pump mechanisms 38. The rotating conduit 32 is U-shaped, and as shown in Figure 8, elbows 321 are installed at both ends of the rotating conduit 32. Both sets of fixed conduits 31 are installed bent laterally, and the elbows 321 at both ends of the rotating conduit 32 are rotatably connected to the lateral portions of the two sets of fixed conduits 31 and are dynamically sealed radially, thus directly communicating with each other. In this way, the entire rotating conduit 32 can be rotated around the two sets of fixed conduits 31 by the action of the first drive mechanism 33 in order to ensure communication. Furthermore, the two sets of fixed pipelines 31 are connected by branch pipes, and / or both ends of the rotating pipeline 32 are connected by branch pipes, so that if one set of pump mechanisms 38 fails or malfunctions, the other set of pump mechanisms 38 can maintain the water flow supply to the two spray arms 34, maintain the continuation of work, and avoid interruption. A connecting sleeve 352 is fixedly installed at the upper end of the flow guide member 35. As shown in Figure 8, the connecting sleeves 352 of both flow guide members 35 are fitted onto the rotating pipe 32. In this embodiment, the flow guide member 35 is connected to the rotating pipe 32 by the connecting sleeve 352, and the flow guide member 35 is in communication with the connecting sleeve 352. Specifically, the flow guide member 35 dynamically seals the connecting sleeve 352 and the rotating pipe 32. Additionally, a water passage hole is provided in the side wall of the rotating pipe 32 in the portion overlapping with the connecting sleeve 352. The water flow in the rotating pipe 32 enters the flow guide member 35 through the water passage hole along the connecting sleeve 352 and flows from the flow guide member 35 to the injection arm 34 along the water supply end of the injection arm 34.

[0036] A single injection arm 34 has multiple front nozzles 3411, and the multiple front nozzles 3411 are installed along the height direction of the injection arm 34. Specifically, the single injection arm 34 includes multiple sets of first injection pipes 341, the multiple sets of first injection pipes 341 of different lengths, and the multiple sets of first injection pipes 341 are installed in parallel in order of length, that is, from the shortest to the longest. Furthermore, all of the multiple sets of first injection pipes 341 are in communication with a flow guide member 35, and each of the multiple sets of first injection pipes 341 is equipped with a front nozzle 3411. As shown in Figures 12 and 13, the front nozzle 3411 of the shortest of the multiple sets of first injection tubes 341 is installed on the side of that first injection tube 341 away from the other first injection tubes 341, the front nozzles 3411 of the remaining first injection tubes 341 are installed in a region longer than the adjacent first injection tubes 341, and all the front nozzles 3411 of the first injection tubes 341 are installed facing the same direction, and as shown in Figures 10 and 11, in the front view of the injection arm 34, the front nozzles 3411 of the multiple sets of first injection tubes 341 are installed along the height direction of the injection arm 34.

[0037] The flow guide member 35 is equipped with a flow guide plug 351 for shutting off or opening some of the shorter first injection pipes 341 among the multiple sets of first injection pipes 341, and since the multiple sets of first injection pipes 341 are installed in parallel in order of length, the shorter side is specifically the side where the shortest first injection pipe 341 of the injection arm 34 is located, and the number of first injection pipes 341 that can be shut off or opened by the flow guide plug 351 in a single injection arm 34 is less than the total number of first injection pipes 341 in the injection arm 34. If there are at least two sets of first injection pipes 341 that can be shut off or opened by the flow guide plug 351, there are at least two sets that are counted sequentially along the length direction starting from the shortest first injection pipe 341. When the trench to be dug is deeper, the jet arm 34 sinks deeper into the seabed, and as shown in Figure 1, all the first jet tubes 341 are submerged in the seabed, and all the front nozzles 3411 are basically not higher than the seabed, meaning all the front nozzles 3411 participate in the seabed soil crushing and trenching work. When the trench to be dug is shallower, as shown in Figure 2, the jet arm 34 sinks shallower into the seabed, and in this case, some of the front nozzles 3411 are clearly higher than the seabed and do not participate in the seabed soil crushing and trenching work. By using the guide plug 351 to block the first jet tube 341 where the front nozzles 3411 are located, there is no jet of water being injected into the first jet tube 341 located above the seabed, and all the water flow is guided into the first jet tube 341 located inside the seabed, improving the utilization efficiency of the jet water flow and the trenching efficiency. The flow guide plug 351 is located above the first injection pipe 341 in the flow guide member 35. Specifically, the flow guide plug 351 includes a fourth drive mechanism and a plug body. The fourth drive mechanism is preferably a hydraulic cylinder, the cylinder body side of which is fixedly installed on the flow guide member 35, and the plug body installed on the piston side of the hydraulic cylinder. The plug body is inserted inside the flow guide member 35 and dynamically sealed with the flow guide member 35. The hydraulic cylinder drives the plug body toward the first injection pipe 341, causing it to be packed into the first injection pipe 341 to achieve shutoff, and the hydraulic cylinder drives the plug body toward the first injection pipe 341 to achieve opening.

[0038] The present invention further comprises a third drive mechanism 37 that can adjust the distance between two injection arms 34 by driving a flow guide member 35 to move axially along a rotating conduit 32, thereby making it suitable for cutting grooves of different widths. The axial stroke of the flow guide member 35 in the rotating conduit 32 is the axial stroke of the connecting sleeve 352 in the rotating conduit 32, and in embodiments of the present invention based on a dynamic seal, the dynamic seal between the connecting sleeve 352 and the rotating conduit 32 in the flow guide member 35 further includes an axial dynamic seal, i.e., the flow guide member 35 further has a stroke to move axially in the rotating conduit 32, and when the connecting sleeve 352 moves axially in the rotating conduit 32, the water passage is always within the overlapping range of the connecting sleeve 352 and the rotating conduit 32, and in embodiments of the present invention connected by flexible piping, the length of the flexible piping should be sufficient to satisfy the movement stroke of the flow guide member 35. After ensuring that the distance between the two injection arms 34 is adjusted, the two injection arms 34 can maintain communication with the rotating conduit 32 by the flow guide member 35. The third drive mechanism 37 is a hydraulic cylinder, which is connected between two flow guide members 35 to synchronously drive the two flow guide members 35. Alternatively, two hydraulic cylinders are installed, with mounting rods 322 fixed to the rotating pipeline 32, and the cylinder bodies of both hydraulic cylinders are fixed to the mounting rods 322, with the pistons connected to correspond to the two flow guide members 35.

[0039] Multiple sets of the first injection tubes 341 of the two injection arms 34 are each equipped with inner nozzles 3412, the inner nozzle 3412 of the shortest of the multiple sets of first injection tubes 341 is located inside the first injection tube 341, the front nozzles 3411 of the remaining first injection tubes 341 are located inside a region longer than the adjacent first injection tube 341, and the inner nozzles 3412 of the two injection arms 34 are positioned facing each other. When the width of the groove to be made is wider, the distance between the two injection arms 34 is greater, and the soil located in the center of the groove may not be liquefied. The installation of the inner nozzles 3412 allows for the formation of opposing jet streams along the width direction of the groove within the groove, liquefying the soil located between the two injection arms 34, thereby helping to cut wide grooves based on the large diameter cable 100 and ensuring the groove shape of wide grooves, further improving flexibility of use.

[0040] Tail nozzles 3413 are installed at the bottom of both injection arms 34, and the injection direction of the tail nozzles 3413 is set to be opposite to the injection direction of the front nozzles 3411. That is, the direction of the jet ejected from the tail nozzles 3413 is opposite to the direction of the jet ejected from the front nozzles 3411, and the jet stream ejected from the tail nozzles 3413 is parallel to the bottom of the groove. The installation of the tail nozzles 3413 allows the high-pressure water flow in the injection arms 34 to be used to generate a horizontal jet stream in the groove in the opposite direction to that of the front nozzles 3411 after the front nozzles 3411 have cut the groove, continuously liquefying the soil in the groove behind, maintaining the groove shape, reducing the amount of mud and sand backfilled before the two injection suction assemblies begin work, and reducing the requirements for the suction strength and water pressure of the two injection suction assemblies. In particular, when the seabed soil is very soft, the bending radius of the cable is large, and the distance between the two jet suction assemblies and the two jet arms 34 is large, the installation of the tail nozzle 3413 can work in cooperation with the two jet suction assemblies to better ensure the groove shape and depth of the groove before the cable is completely submerged. Preferably, the tail nozzle 3413 is installed at the bottom of the first jet tube 341, which is the longest in the jet arm 34, so that the tail nozzle 3413 can be maintained at the bottom of the groove even if the depth of the grooves opened is different.

[0041] As shown in Figure 14, the present invention further comprises a front injection mechanism 5 installed on the system body 1 and located between the two injection arms 34. The installation of the front injection mechanism 5 allows the injection arms 34 to perform a pre-injection before injection and soil crushing. On the one hand, it may be used to remove sludge, crushed stone, and marine organisms adhering to the seabed surface and cables. On the other hand, it may be used to cut a shallow groove on the seabed surface in front of the injection arms 34 to form a pre-cut groove. This reduces the difficulty of soil crushing and groove cutting by the injection arms 34 when turning a curve, contributing to groove cutting and cable burial work while changing direction. The front injection mechanism 5 includes a support pipe 51, a front injection pipe 52, and a fifth drive mechanism 53. The support pipe 51 is connected to an external water supply unit, the front injection pipe 52 is rotatably mounted at the lower end of the support pipe 51 and dynamically sealed, and a front nozzle 521 for ejecting a jet of water is mounted at the lower end of the front injection pipe 52. The fifth drive mechanism 53 is specifically a hydraulic cylinder, which is mounted between the support pipe 51 and the front injection pipe 52 by a hinge connection. Specifically, as shown in Figure 14, there are two front injection pipes 52, both of which are bent and mounted, with the ends away from the front nozzle 521 rotatably connected to the lower end of the support pipe 51 and dynamically sealed, and both front injection pipes 52 form a U-shaped nozzle structure and are fixedly connected by a rod body. The hydraulic cylinder is specifically hinge-connected between the support pipe 51 and the rod body.

[0042] As shown in Figures 15 to 19, the injection suction device 4 further includes a second laying mechanism, a support base 41, and a first drive assembly 44, wherein the second laying mechanism is installed at the rear end of the system body 1, the support base 41 is installed at the end of the second laying mechanism away from the system body 1, a single second injection pipe 43 is fixedly connected to a single suction conduit 42, and two injection suction assemblies are installed by the support base 41 at the end of the second laying mechanism away from the system body 1, the two injection suction assemblies are spaced apart and passable to a cable, and in operation, the cable can fall into the trench from between the two injection suction assemblies. This installation method allows for the discharge of mud and sand from inside the trench and continuous soil liquefaction without affecting the normal settlement of the cable. The lower end of the second injection pipe 43 and the lower end of the suction pipe 42 are installed in parallel, and an injection port 432 is installed on the side of the second injection pipe 43, specifically located on the side away from the two injection arms of the second injection pipe 43, with the injection direction of the injection port 432 being perpendicular to the suction direction of the suction port 423, and when the injection suction device 4 is operating, the two injection suction assemblies are used simultaneously, with both the suction port 423 and the injection port 432 located in the groove, with the suction port 423 positioned toward the inner bottom surface of the groove, and the injection direction of the injection port 432 positioned along the length of the groove, i.e., the injection direction is toward the right in Figures 1 and 2. When the injection port 432 is located in the groove, the injection port 432 ejects a horizontal jet of water in the direction away from the two injection arms along the length of the groove.

[0043] When the bending radius of the cable is large or the depth of the groove to be opened is deep, preferably the second laying mechanism is installed in an extension direction away from the system body 1 to increase the distance between the two jet suction assemblies and the two jet arms, thereby mitigating the slack of the cable from the seabed to the bottom of the groove. At least one of the two jet suction assemblies is slidably mounted on the support base 41, and the first drive assembly 44 drives the slidably mounted jet suction assembly to move, thereby adjusting the distance between the two jet suction assemblies and adapting to grooves of different widths.

[0044] A pipe diameter reduction section is installed in the suction pipe 42 between the first water inlet 421 and the suction port 423, and the suction port 423 is installed in communication with the side of the pipe diameter reduction section. Specifically, the pipe diameter reduction section is formed in the suction pipe 42 by being installed such that the central position between the first water inlet 421 and the suction port 423 becomes narrower, and the lower end of the suction pipe 42 is formed by an extension pipe being installed in communication in the vertical direction with the side of the pipe diameter reduction section, and the end of the extension pipe is installed to become the suction port 423. Based on the Venturi effect, when the water flow flows rapidly along the first water inlet 21 to the outlet 22, a low pressure is generated at the suction port 23, causing an adsorption effect. Both the suction line 42 and the second injection pipe 43 are equipped with pumps that drive the water flow so that it flows from the first water inlet 421 to the outlet 422, and pumps that drive the water flow so that it flows from the second water inlet 431 to the injection nozzle 432. In the suction line 42, the pump is positioned at the first water inlet 421 to ensure that the water flows from the first water inlet 421 to the outlet 422. In the second injection pipe 43, the pump is positioned at the second water inlet 431, but it may be positioned at any other location in the second injection pipe 43, as long as the water flows from the second water inlet 431 to the injection nozzle 432.

[0045] The injection suction device further includes a support base 41 and a first drive assembly 44, wherein two injection suction assemblies are mounted on the support base 41 at the end of the second laying mechanism away from the system body 1, and at least one of the two injection suction assemblies is slidably mounted on the support base 41, and the first drive assembly 44 moves the slidably mounted injection suction assembly to adjust the distance between the two injection suction assemblies, thereby accommodating grooves of different widths.

[0046] Preferably, both of the injection suction assemblies are slidably mounted on a support base 41, and the first drive assembly 44 is located between the two injection suction assemblies, with a fixed end connected to one injection suction assembly and a movable end connected to the other injection suction assembly, thereby ensuring symmetry of the two injection suction assemblies on the support base 41, and also reducing the travel stroke of a single injection suction assembly under the same spacing adjustment. Specifically, the suction lines 42 in both injection suction assemblies are slidably connected to the support base 41 by sliders, the first drive assembly 44 is a hydraulic cylinder, with the cylinder body side fixed to the suction line 42 in one injection suction assembly and the piston side fixed to the suction line 42 in the other injection suction assembly, and the number of first drive assemblies 44 may be set to two, as shown in Figure 16.

[0047] The suction pipe 42 has a water inlet at one end and is installed laterally at the other end, with the outlet 422 located at the laterally installed end, and the suction pipe 42 has a pipe diameter contraction section between the first water inlet 421 and the outlet 422, with an extension pipe extending vertically from the side of the pipe diameter contraction section, with the suction port 423 located on the extension pipe, and based on the Venturi effect, when the water flow flows rapidly along the first water inlet 421 to the outlet 422, a low pressure is generated at the suction port 423, causing an adsorption effect. Both the suction line 42 and the second injection pipe 43 are equipped with pumps that drive the water flow so that it flows from the first water inlet 421 to the outlet 422, and pumps that drive the water flow so that it flows from the second water inlet 431 to the injection nozzle 432. In the suction line 42, the pump is positioned at the first water inlet 421 to ensure that the water flows from the first water inlet 421 to the outlet 422. In the second injection pipe 43, the pump is positioned at the second water inlet 431, but it may be positioned at any other location in the second injection pipe 43, as long as the water flows from the second water inlet 431 to the injection nozzle 432.

[0048] An end cover 424 is installed at the position of the discharge port 422 in the suction pipe 42, and the degree of opening and closing of the end cover 424 and the discharge port 422 is adjustable, thereby adjusting the drainage flow rate of the discharge port 422 according to the work situation. If sludge clogs the suction port 423, the end cover 424 closes the discharge port 422, and at this time the water flow direction is from the first water inlet 421 to the suction port 423, so the suction port 423 can be washed in the opposite direction to remove the blockage.

[0049] The present invention further comprises a second drive assembly 45, which moves or rotates the end cover 424 to adjust the degree of opening and closing between the end cover 424 and the outlet 422. The end cover 424 is installed at the end of the outlet 422 of the suction line 42 by hinge connection, and the second drive assembly 45 is specifically a hydraulic cylinder, the cylinder body side of which is hinged to the suction line 42 and the piston side of which is hinged to one side of the end cover 424, and the opening and closing of the end cover 424 is driven by the extension and retraction of the piston of the hydraulic cylinder.

[0050] The present invention further comprises a third drive assembly 48, which drives the support base 41 up and down, thereby enabling the return and descent of the two injection suction assemblies and adjustment of their lower heights, thereby accommodating grooves of different depths.

[0051] The present invention further comprises a fixed frame 46 and a movable frame 47, wherein the fixed frame 46 is connected to the system body 1, the movable frame 47 is hinged at one end to the fixed frame 46 and at the other end to a support base 41, and the third drive assembly 48 is installed between the fixed frame 46 and the support base 41 by a hinge connection, thereby forming a connecting rod mechanism. This installation method enables the laying, return, and adjustment of the lowering height of two injection suction assemblies, and, in combination with two injection arms 34 whose lowering height can be adjusted, enables the creation of grooves of different depths and the burying of the cable 100. Figure 1 shows the situation when the two injection arms 34 and the two injection suction assemblies are lowered to a greater depth, in which case the depth of the cut groove is greater, and Figure 2 shows the situation when the two injection arms 34 and the two injection suction assemblies are lowered to a shallower depth, in which case the depth of the cut groove is shallower, thereby ensuring that the cable 100 is effectively and reliably buried in both deep and shallow grooves. On the other hand, compared to a linear drive mechanism directly installed vertically, when using a connecting rod mechanism to drive two injection suction assemblies to return and lower them, if the return and lowering strokes are similar, it occupies less vertical space, allowing other equipment to be easily mounted on the system body 1, and also reduces interference with other equipment.

[0052] The third drive assembly 48 is specifically a hydraulic cylinder, the cylinder body side of which is hinged to the fixed frame 46, and the piston side of which is hinged to the support base 41. The number of third drive assemblies 48 may be set to two, and the arrangement is shown in Figures 15, 17, and 19.

[0053] The present invention further comprises a fourth drive assembly 49, wherein a hinged connection portion 461 is installed on the fixed frame 46, the fixed frame 46 is hinged to the system body 1 by the hinged connection portion 461, and the axis of the hinged connection portion is installed along the vertical direction of the support base 41, i.e., installed vertically, and the fourth drive assembly 49 is used to rotate the fixed frame 46 around the hinged connection portion in the system body 1 to achieve left and right swaying of the entire device, i.e., the state shown in Figures 5 and 6, thereby adapting to curved regions or curved grooves. Specifically, the fourth drive assembly 49 is a hydraulic cylinder, the cylinder body side of which is hinged to the fixed frame 6, and the piston side of which is hinged to the system body 1, and the extension and retraction of the piston side drives left and right swaying of the entire device, in coordination with the pivoting motion of the work system.

[0054] The present invention further provides a method for working with underwater jets for groove cutting and cable laying, the method using the above-described underwater jet system for groove cutting and cable laying, Step S1 involves dropping a work system for trenching and cable laying using an underwater jet onto the seabed where trenching and cable laying are to be performed, and positioning the projections of the two jet arms 34 on the seabed to correspond to both sides of the cable 100, that is, in the height direction, the positions of the two jet arms 34 and the cable 100 do not overlap, thereby avoiding crushing of the cable 100 during the descent of the jet arms 34 and during trenching work. Step S2 involves laying two jetting arms 34 facing downwards and using the front nozzles 3411 of the two jetting arms to eject a jet of water, in order to perform trench cutting and cable laying work using an underwater jet. The underwater traveling device 2 travels along the length of the cable 100 on the seabed, crushing the seabed soil along the length of the cable 100 with jets to cut a trench, while the tail nozzle 3413 ejects a jet of water away from the direction of the front nozzle 3411, continuously liquefying the soil in the trench, maintaining the trench shape and depth, and reducing backfilling and accumulation of mud and sand, as well as collapse on both sides of the trench. Step S3 includes laying the injection suction device 4 facing downwards, inserting the two injection suction assemblies into the trench, sucking up mud and sand from the trench through the suction port 423 of the suction conduit 42 before the cable falls into the trench, and discharging the mud and sand to the outside of the trench through the discharge port 422, thereby ensuring that the trench depth meets the work requirements, and ejecting a horizontal jet of water from the nozzle 432 in a direction away from the two injection arms 34 within the trench, continuously liquefying the soil in the trench, and allowing the cable 100 to naturally sink to the bottom of the trench from between the two injection suction assemblies.

[0055] The jet stream ejected from the nozzle 432 only needs to maintain the groove shape and does not need to perform any additional soil crushing action. Therefore, the required water pressure is less than the water pressure of the jet stream ejected from the front nozzle 3411. In other words, in S3, the water pressure of the jet stream ejected from the nozzle 432 is less than the water pressure of the jet stream ejected from the front nozzle 3411.

[0056] As those skilled in the art will understand, the descriptions of any of the above embodiments are merely illustrative and do not imply that the scope of protection of this application is limited to these examples. Technical features of the above embodiments or different embodiments can be combined without departing from the concept of this application, the steps can be carried out in any order, and many other variations of different aspects of one or more embodiments of this application described above exist and are not described in detail for the sake of brevity.

[0057] One or more embodiments of this Application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this Application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this Application should be included within the scope of protection of this Application. [Explanation of symbols]

[0058] 1. System Unit 2. Underwater Traveling Device 21 Shoe 22 Crawler mechanism 221 Crawler Module 23. First drive module 24 Connecting rod 25 Vertical propellers 26 horizontal propellers 27 rotatable propellers 271 Connecting Rod 272 Propeller Body 28. Second drive module 3. Injection-type soil crushing device 31 Fixed pipe line 32 Rotating conduits 321 Elbow 322 Mounting Rod 33 First drive mechanism 34 injection arms 341 1st injection pipe 3411 Front Nozzle 3412 Inner nozzle 3413 Tail nozzle 35 Flow guiding member 351 Flow diversion plug 352 Connection Sleeve 36. Second drive mechanism 37 Third drive mechanism 38 Pump mechanism 4 Injection suction device 41 Support base 42 Suction line 421 1st water supply port 422 Outlet 423 Suction port 424 End Cover 43 2nd injection pipe 431 2nd water supply port 432 Nozzle 44. First drive assembly 45. Second drive assembly 46 Fixed Frame 461 Hinge connection 47 Movable Frame 48. Third drive assembly 49. Fourth drive assembly 5. Front injection mechanism 51 Support pipe 52 Front Injector Pipe 521 Front Nozzle 53 Fifth drive mechanism 100 Cables

Claims

1. A work system for trenching and cable laying using an underwater jet, The system unit (1) and A submersible traveling device (2) is installed at the lower end of the main system body (1), A jet-type soil crushing device (3) is located at the front end of the main system body (1) and includes two jet arms (34) each equipped with a front nozzle (3411) for cutting grooves in the seabed by ejecting a jet of water, The system is installed at the rear end of the main body (1) and includes a suction pipe (42) and a second injection pipe (43), the suction pipe (42) having an outlet (422) and a suction port (423), the suction port (423) being used toward the bottom of the trench, the outlet (422) being positioned higher than the suction port (423) and laterally relative to the suction port (423), and the suction pipe (42) is used to suck up mud and sand from inside the trench from the suction port (423) and discharge the mud and sand to the outside of the trench from the outlet (422) before the cable sinks to the bottom of the trench, Equipped with, The second injection pipe (43) is located behind the suction pipe (42), and an injection nozzle (432) is installed in the second injection pipe (43). The direction of the injection from the injection nozzle (432) is set horizontally away from the suction pipe (42), and the second injection pipe (43) is used to maintain the groove shape as the cable sinks to the bottom of the groove by ejecting a horizontal jet of water from the injection nozzle (432) after the suction pipe (42) has sucked up the mud and sand from inside the groove, thereby cleaning the inner wall and bottom of the groove along the length of the groove. A work system for trenching and cable laying using an underwater jet, characterized by its features.

2. The water jet work system for trenching and cable laying according to claim 1, wherein the jet-type soil crushing device (3) further includes a first laying mechanism, the first laying mechanism includes a fixed conduit (31), a rotating conduit (32), a first drive mechanism (33), and a second drive mechanism (36), the fixed conduit (31) being fixed to the system body (1), the rotating conduit (32) being rotatably installed on and communicating with the fixed conduit (31), the first drive mechanism (33) being used to rotate the rotating conduit (32) around the fixed conduit (31), two jet arms (34) both being rotatably installed on and communicating with the rotating conduit (32), and the second drive mechanism (36) being used to rotate the two jet arms (34) around the rotating conduit (32).

3. The water jet work system for trenching and cable laying according to claim 2, further comprising a third drive mechanism (37) that can adjust the distance between two jet arms (34) by driving two jet arms (34) to move along the axial direction of a rotating pipe (32).

4. The work system for trenching and cable laying using an underwater jet according to claim 2 or 3, characterized in that two suction lines (42) are installed, the two suction lines (42) are installed at intervals along the width direction of the system body (1), and the interval between the two suction lines (42) is adjustable, and two second jets (43) are installed, the two second jets (43) are installed at intervals along the width direction of the system body (1), and the interval between the two second jets (43) is adjustable.

5. The injection suction device (4) further includes a second laying mechanism, a support base (41), and a first drive assembly (44), the second laying mechanism being installed at the rear end of the system body (1), the support base (41) being installed at the end of the second laying mechanism away from the system body (1), a single second injection pipe (43) being fixedly connected to a single suction line (42), and the single second injection pipe (43) and the suction line (42) fixedly connected thereto constitute one injection suction assembly, both injection suction assemblies being installed on the support base (41), the two injection suction assemblies being spaced apart, and a cable being able to fall into a groove between the two injection suction assemblies. The underwater jet work system for grooving and cable laying according to claim 4, characterized in that at least one of the two jet suction assemblies is slidably mounted on a support base (41), and the first drive assembly (44) adjusts the distance between the two jet suction assemblies by driving the slidably mounted jet suction assembly to move.

6. The underwater jet work system for groove cutting and cable laying according to claim 5, characterized in that a tail nozzle (3413) is installed at the bottom of both of the two jet arms (34), and the jet direction of the tail nozzle (3413) is set to be opposite to the jet direction of the front nozzle (3411).

7. The underwater jet work system for furrowing and cable laying according to claim 5 or 6, characterized in that the laying height of the two jet arms (34) and the two jet suction assemblies is adjustable.

8. A work system for trenching and cable laying using an underwater jet, as described in any one of claims 1 to 3, 5, and 6, characterized in that the suction conduit (42) has a first water inlet (421) at one end and is installed laterally at the other end, with a discharge port (422) located at the laterally installed end, the suction conduit (42) has a pipe diameter contraction section installed between the first water inlet (421) and the discharge port (422), an extension pipe is installed vertically from the side of the pipe diameter contraction section, a suction port (423) is located at the extension pipe, and an end cover (424) is installed at the position of the discharge port (422) in the suction conduit (42), and the degree of opening and closing of the end cover (424) and the discharge port (422) is adjustable.

9. An underwater jet-powered work system for groove cutting and cable laying according to any one of claims 1 to 3, 5, and 6, further comprising a front jet mechanism (5) installed at the front end of the system body (1) and located in front of the two jet arms (34), and equipped with a front nozzle (521) to sweep and / or pre-cut grooves on the seabed before the two jet arms (34) begin work.

10. A method for cutting grooves and laying cables using an underwater jet, wherein the work system for cutting grooves and laying cables using an underwater jet is described in any one of claims 1 to 9, and the work method is: Step S1 involves dropping a work system for trenching and cable laying using an underwater jet onto the seabed where trenching and cable laying are to be performed, and positioning the projections of the two jet arms (34) on the seabed to correspond to both sides of the cable (100). The underwater jet-powered work system for trench cutting and cable laying involves an underwater traveling device (2) traveling along the length of the cable (100) on the seabed, and ejecting a jet stream of water from the front nozzles (3411) of two jet arms (34) to break up the seabed soil along the length of the cable (100) and cut a trench (step S2). A method for trench cutting and cable laying using an underwater jet, characterized by including step S3, which involves sucking up mud and sand from inside the trench from the suction port (423) of the suction conduit (42) before the cable falls into the trench, discharging the mud and sand to the outside of the trench from the discharge port (423), and spraying a horizontal jet of water from the spray port (432) to clean the inner wall and bottom of the trench along the length of the trench, thereby continuously liquefying the soil inside the trench, maintaining the trench shape, and allowing the cable (100) to sink naturally to the bottom of the trench.

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