A large prefabricated structure undocking method based on self-owned traction system

Abstract

The application discloses a large prefabricated structure out of dock method based on self-owned traction system. The traction system comprises a winch and a steering saddle on the top of the prefabricated structure, a mooring post on the top of the dock wall, and a cable. The traction system has at least four groups. The method comprises the following steps: step 1, connecting the cable with the two mooring posts closest to the dock mouth for the front traction system of the prefabricated structure, and connecting the cable with the two mooring posts at the back for the rear traction system; step 2, filling water into the dock, and starting the winch to wind or release the cable according to the height difference between the prefabricated structure and the top of the dock wall; step 3, starting the winch to synchronously tighten the front cable and synchronously release the rear cable to pull the prefabricated structure to the dock mouth; and step 4, connecting the left rear part and the right rear part of the prefabricated structure with the adjacent mooring posts by means of auxiliary ropes, connecting the rear cable to the mooring posts closer to the prefabricated structure, and then releasing the auxiliary ropes.

Description

TECHNICAL FIELD

[0001] The present application relates to the offshore sinking well construction technical field, and particularly relates to a large prefabricated structure undocking method. BACKGROUND

[0002] With the rapid development of construction technology in the infrastructure field, large sinking wells, caissons and other prefabricated structures have been widely used in various projects. Due to the influence of engineering characteristics, construction environment and other factors, some projects cannot manufacture these large prefabricated structures in the construction area, so they often choose to weld and assemble them in the dry environment of the dock. After the large prefabricated structure is manufactured, the dock gate is opened to fill water into the dock to a sufficient height to make it float. Then the tugboat enters the dock and uses the mooring columns and other structures of the large prefabricated structure to tow it to the bridge site.

[0003] The above is the traditional construction method for undocking large sinking wells, caissons and other large prefabricated structures, which has the following disadvantages: (1) If the width of the dock is insufficient, auxiliary tugs cannot be arranged on the side of the large prefabricated structure, and only the front main tug can be used for towing. Due to the lack of lateral restraint, the towed prefabricated structure may deviate during movement, causing collision with the dock and damage to the prefabricated structure and the dock; (2) When auxiliary tugs are working on the side, improper operation of the front main tug may cause the towed prefabricated structure to deviate from the predetermined track, which may squeeze the auxiliary tugs together with the dock wall, causing great safety risks to the ship and construction personnel; (3) This construction method requires a large number of tugboats, which has high rental costs; and this method requires high synchronization and coordination of construction, so more manpower is also required. SUMMARY

[0004] The main technical problem to be solved by the present application is to provide a large prefabricated structure undocking method, which uses its own towing system to stably and safely tow the prefabricated structure out of the dock with low construction cost.

[0005] To solve the above technical problems, the present application provides a large prefabricated structure undocking method based on its own towing system, which is based on the following hardware basis:

[0006] The dock includes a dock chamber, a dock wall and a dock gate. The dock wall extends on both sides of the dock chamber, and the dock gate is located at one end of the dock chamber close to the water area. The prefabricated structure is located in the dock chamber and is undocked towards the dock gate.

[0007] The traction system comprises a winch, a steering saddle, a plurality of mooring posts and a cable; the winch is installed on a construction platform on the top of the prefabricated structure to wind and unwind the cable; the steering saddle is installed on the edge of the top of the prefabricated structure; the steering saddle is configured with a horn-shaped cable passage, the horn mouth of the cable passage faces the outside of the prefabricated structure; the plurality of mooring posts are installed on the top of the dock walls on both sides of the dock and are arranged at intervals along the extension direction of the dock walls; the cable comprises a first end and a second end, the first end is fixed to the winch, the second end extends from the winch, passes through the cable passage of the steering saddle and is finally connected with the mooring posts;

[0008] At least four groups of the traction system are arranged in the dock, including traction system A, traction system B, traction system C and traction system D; in the direction of the prefabricated structure out of the dock, the traction system A and the traction system B are arranged at the front of the construction platform and are respectively located on the left and right sides; the traction system C and the traction system D are arranged at the rear of the construction platform and are respectively located on the left and right sides;

[0009] The method comprises the following steps:

[0010] Step 1: connecting the cable; in the traction system A, the cable is connected with the mooring post closest to the left side of the dock entrance; in the traction system B, the cable is connected with the mooring post closest to the right side of the dock entrance; in the traction system C, the cable is connected with one of the mooring posts behind the left side of the steering saddle; in the traction system D, the cable is connected with one of the mooring posts behind the right side of the steering saddle;

[0011] Step 2: water injection and floating; water is injected into the dock chamber until the water level height meets the out-of-dock condition; during the water injection process, the top difference between the prefabricated structure and the dock wall needs to be considered to start the winch of each group to wind and unwind the cable of each group;

[0012] Step 3: traction out of the dock; for the traction system A and the traction system B, the winch in the system is started to synchronously tighten the two cables in front, at the same time, for the traction system C and the traction system D, the winch in the system is started to synchronously release the two cables behind, to pull the prefabricated structure to move to the dock entrance.

[0013] In a preferred embodiment, after step 3, there is step 4: system transformation;

[0014] The left and right rear portions of the prefabricated structure are connected to the adjacent mooring bitts by at least two auxiliary ropes, and the auxiliary ropes are tensioned; then, in the traction system C, the second end of the cable is released from the original mooring bitt and connected to the adjacent mooring bitt behind the left side of the turning saddle; in the traction system D, the second end of the cable is released from the original mooring bitt and connected to the adjacent mooring bitt behind the right side of the turning saddle; further, the auxiliary ropes are released.

[0015] In a preferred embodiment, in step 3, when the prefabricated structure approaches the dock entrance, the reeling speed of the winch in the traction system A and the traction system B and the releasing speed of the winch in the traction system C and the traction system D are controlled to slow down the prefabricated structure.

[0016] In a preferred embodiment, in step 3, the moving speed of the prefabricated structure is not greater than 0.5 m / s.

[0017] In a preferred embodiment, in step 1, after the cables in each group of traction systems are connected correctly, the winches in each group are started to tighten the cables.

[0018] In a preferred embodiment, in step 2, when the prefabricated structure is floating, the winches in each group are started to coordinate the lengths of the cables in each group to fine-tune the center line of the prefabricated structure to coincide with the center line of the dock chamber.

[0019] In a preferred embodiment, in step 2, the top of the prefabricated structure is higher than the top of the dock wall; during the water injection process, the winches in each group are started to release the cables in each group synchronously.

[0020] In a preferred embodiment, the direction of the winch to reel or release the cable is different from the extension direction of the cable passage in the turning saddle; the traction system further comprises a reversing wheel; the reversing wheel is installed on the construction platform and located near the intersection of the center lines of the winch and the turning saddle; the reversing wheel has a rotational degree of freedom in the horizontal plane; after the cable is drawn out from the winch, the cable is partially wound around the reversing wheel and extends to the turning saddle.

[0021] In a preferred embodiment, the turning saddle comprises a bottom plate, side plates and a movable top plate; the bottom plate is trumpet-shaped and inclined or curved downward toward the trumpet mouth; two arc-shaped side plates are fixed to the left and right sides of the extension direction of the bottom plate and jointly form a trumpet-shaped cable passage with the top of the bottom plate; the two side plates and the bottom of the bottom plate form a support cavity, which is filled with concrete; the side plates are fixed with stiffening frames on the sides away from the cable passage; the movable top plate is detachably connected to the top of the two stiffening frames to span above the cable passage.

[0022] In a preferred embodiment, the traction system further comprises a rope sleeve and a shackle; the rope sleeve is sleeved on the bitt through the shackle connected head to tail; the shackle is openable and closable; the second end of the cable is provided with a ring-shaped rope loop; in steps 1 to 3, the cable is connected with the bitt by threading the rope loop into the shackle.

[0023] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0024] The method provided by the present application uses the winch of the large prefabricated structure to wind and unwind the cable connected to the dock wall, and uses the principle of "action and reaction" to safely and stably pull the prefabricated structure forward and out of the dock. This method uses the self-provided traction system to replace the tugboat, skillfully avoiding the problem of lateral extrusion of the prefabricated structure caused by improper main towing operation and limited space, etc., thereby improving the construction safety and reducing the rental cost investment.

[0025] Secondly, at least four groups of traction systems cooperatively control the accurate movement of the prefabricated structure in four directions, i.e., front, back, left and right, and maintain dynamic balance. This method effectively solves the problem of left and right deviation and collision of the prefabricated structure with the dock wall caused by abandoning lateral auxiliary towing in a relatively narrow dock, and thus has high engineering applicability.

[0026] In addition, because this method can accurately control the prefabricated structure by using the winch, the prefabricated structure has higher braking performance when encountering an emergency or approaching a destination, which is a deficiency of most towing methods. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 FIG. 1 is a plan view of the traction system installed on a steel caisson according to the present application;

[0028] Figure 2 FIG. 1 is a plan view of the traction system installed on a steel caisson according to the present application;

[0029] Figure 3 FIG. 1 is a plan view of the traction system installed on a steel caisson according to the present application;

[0030] Figure 4 FIG. 1 is a plan view of the traction system installed on a steel caisson according to the present application;

[0031] Figure 5 FIG. 1 is a plan view of the traction system installed on a steel caisson according to the present application;

[0032] Figure 6A perspective view of the turning saddle described in Embodiment 1 of the present application;

[0033] Figure 7 A perspective view of the mooring bitt, rope sleeve and shackle described in Embodiment 1 of the present application;

[0034] Figure 8 A perspective view of the steel caisson in the initial position before moving out of the dock described in Embodiment 1 of the present application;

[0035] Figure 9 A perspective view of the steel caisson in the initial position before moving out of the dock described in Embodiment 1 of the present application;

[0036] Figure 10 A perspective view of the steel caisson in the initial position before moving out of the dock described in Embodiment 1 of the present application;

[0037] Figure 11 A perspective view of the steel caisson in the initial position before moving out of the dock described in Embodiment 1 of the present application;

[0038] In the figure, the following are marked: 1 - hoist, 10 - first base, 2 - reversing wheel, 20 - second base, 21 - fixed frame, 211 - fixed shaft, 212 - limiting part, 3 - turning saddle, 31 - bottom plate, 311 - grouting hole, 32 - side plate, 321 - stiffening framework, 33 - movable top plate, 34 - support cavity, 35 - cable passage, 30 - third base, 301 - pier, 302 - steel corbel, 4 - mooring bitt, 41 - bitt cap, 42 - rope sleeve, 43 - shackle, 5 - cable, 51 - first end, 52 - second end, 53 - rope loop, 6 - steel caisson, 61 - cofferdam, 62 - construction platform, 7 - dock, 71 - dock chamber, 72 - dock wall, 73 - dock entrance, 8 - fiber rope. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application; obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application, and all other embodiments obtained by those of ordinary skill in the art without creative labor based on the embodiments in the present application are within the protection scope of the present application.

[0040] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "provided with", "sleeved / connected", "connected" and the like should be understood in a broad sense. For example, "connected" can be wall-mounted connection, can be detachable connection, or integral connection, can be mechanical connection, can be electrical connection, can be direct connection, can be indirect connection through an intermediate medium, can be internal communication of two elements, and the specific meaning of the above terms in the present application can be understood by those skilled in the art according to the specific circumstances.

[0042] Embodiment 1

[0043] As shown in Figures 1-10 , the present application provides a large prefabricated structure out of the dock method based on self-owned traction system. In this embodiment, the prefabricated structure is a steel caisson 6.

[0044] First, in combination with the drawings, the hardware basis of the method, the dock and the traction system, are described. As shown in Figures 8-10 , the dock 7 includes a dock chamber 71, a dock wall 72, and a dock mouth 73. The dock wall 72 extends on both sides of the dock chamber 71, and the dock mouth 73 is located at one end of the dock chamber 71 close to the water area. The steel caisson 6 is located in the dock chamber 71 and is out of the dock in the direction of the dock mouth 73. The traction system includes a winch 1 installed on the top of the steel caisson 6, a reversing wheel 2, a steering saddle 3, a mooring bitt 4 arranged on the top of the dock wall 72, and a cable 5.

[0045] As shown in Figure 1 , Figure 2 , the winch 1 is installed on the construction platform 62 on the top of the steel caisson 6 through a first base 10. The first base 10 is a rigid space structure welded by a plurality of profile steels. The bottom of the first base 10 is welded on the construction platform 62, and the top is provided with an operation platform for fixing the winch 1 and standing for the operator. In this embodiment, the first profile steel member adopts a double-spliced 25-shaped steel, and the steel grade is 0235B. The overall length of the first base 10 is 6.5 meters, the width is 3.5 meters, and the height is 2.0 meters. The maximum traction force of the winch 1 is 25 tons.

[0046] As shown in Figures 1-4As shown, the reversing wheel 2 is a groove fixed pulley, which is installed on the construction platform 62 through a fixing frame 21 and a second base 20. Similar to the first base 10, the second base 20 is a rigid space structure welded by several profile steels. The bottom of the second base is welded on the construction platform 62, and the top is fixedly connected with the fixing frame 21. The fixing frame 21 is a steel structure. In the traction system, the reversing wheel 2 is used to reverse the cable 5 in the horizontal direction, therefore, the necessary structural features of the fixing frame 21 are: a fixed shaft 211 is arranged in the vertical direction, the reversing wheel 2 is sleeved on the fixed shaft 211, so that the reversing wheel 2 has a rotating degree of freedom in the horizontal plane; secondly, the fixing frame 21 is provided with a limiting part 212 at the bottom and the top of the reversing wheel 2, the limiting part 212 is limited in position with the reversing wheel 2 in the vertical direction, so as to prevent the reversing wheel 2 from being separated from the fixed shaft 211. In this embodiment, the second profile steel is the same as the first profile steel. The second base 20 is 2.0 meters long, 1.0 meter wide and 0.5 meter high in total. The diameter of the reversing wheel 2 is 70 centimeters.

[0047] As Figure 1 , Figure 5 and Figure 6As shown, the turning saddle 3 comprises a bottom plate 31, side plates 32 and a movable top plate 33. In the horizontal plane, the bottom plate 31 is trumpet-shaped, having a relatively wide flared portion and a relatively narrow contracted portion; in the vertical direction, the bottom plate 31 gradually inclines or curves downward from the position close to the contracted portion to the flared portion. Two arc-shaped side plates 32 are welded to the left and right sides of the bottom plate 31 in the extension direction, and together with the top of the bottom plate 31, they form a trumpet-shaped cable passing channel 35 to position and guide the cable 5 when it is reeled in or out. The trumpet mouth of the cable passing channel 35 faces the outside of the steel caisson 6. The two side plates 32 and the bottom of the bottom plate 31 form a support cavity 34. To provide the load-bearing capacity and structural stability of the turning saddle 3, the support cavity 34 is filled with concrete, and correspondingly, the bottom plate 31 is provided with grouting holes 311 to facilitate grouting. The side plates 32 are fixedly connected to stiffening frames 321 on the side facing away from the cable passing channel 35, and the stiffening frames 321 are rigid structures formed by interlaced welding of several steel plates. When the working angle of the steel wire rope is large, the side plates 32 are bent outward by the steel wire rope, and at this time, the vertical stiffening frames 321 can partially transmit the force to the steel caisson 6, achieving force relief. The movable top plate 33 is detachably connected to the top of the two side stiffening frames 321 by a bolt assembly, so as to be arranged above the cable passing channel 35. In this way, the cable passing channel 35 forms a closed loop in the vertical plane, limiting the cable 5 from flying out of the cable passing channel 35 from the top when it passes quickly. In this embodiment, the overall length of the turning saddle 3 is 1.9 meters, the overall width is 1.7 meters, and the overall height is 0.9 meters. The bottom plate 31, the side plates 32, the stiffening frames 321 and the movable top plate 33 are made of steel plates, and the steel grade is Q335. The concrete filled in the support cavity 34 has a grade of C30. Overall, the turning saddle 3 adopts a trumpet-shaped structure, which can adapt to the cable 5 with multiple angles, creating high flexibility for the launching construction of the steel caisson 6; at the same time, this structure reduces the friction between the steel wire rope and the turning saddle 3, making the traction system run more smoothly.

[0048] As Figure 2As shown, the turning saddle 3 is fixed on the top of the cofferdam 61 (hereinafter referred to as "cofferdam 61") of the steel caisson 6 by a third base 30. The third base 30 comprises a pier 301 and a steel bracket 302. The pier 301 is poured on the top of the cofferdam 61 with concrete, which functions to raise the cofferdam 61 to the height of the construction platform 62, so as to facilitate the cooperation with the reversing wheel 2 in the horizontal direction when the turning saddle 3 is installed on the pier 301. In order to facilitate the cable passing, the turning saddle 3 extends a distance outward of the cofferdam 61. Therefore, the pier 301 is fixed with the steel bracket 302 on the outside. The steel bracket 302 is a rigid structure obtained by welding a plurality of steel plates. The top of the steel bracket 302 is welded with the bottom of the turning saddle 3 to support the extended section of the latter. The steel bracket 302 can be fixed with the pier 301 in various ways, for example, the steel bracket 302 can be partially embedded in the pier 301; for example, the pier 301 is externally pre-buried with a connecting plate, and the steel bracket 302 is welded on the connecting plate; for example, the pier 301 is externally wrapped with a steel structure box, and the turning saddle 3 is welded on the outside of the box. As a mature prior art, this connecting mode is not limited herein. In the embodiment, the steel bracket 302 has a total length of 2.6 meters, a width of 2.2 meters, and a height of 1.8 meters, and is welded with 30 millimeter thick Q355 steel plates.

[0049] As shown, Figures 7-10 The mooring column 4 is fixed on the top of the dock wall 72 by a plurality of bolt assemblies. The mooring column 4 is provided with a column cap 41 for limiting. The mooring column 4 is also used with a rope sleeve 42 and a shackle 43. The rope sleeve 42 is a steel wire rope with a diameter of 32 millimeters, and is connected end to end after the rope sleeve 42 is sleeved on the mooring column 4 through the shackle 43. The shackle 43 can be opened and closed to externally connect the rope. In the embodiment, the maximum load capacity of the shackle 43 is 25 tons. A plurality of mooring columns 4 are arranged at intervals in the extension direction of the dock wall 72. The mooring columns 4 on the dock walls 72 on both sides of the dock 7 are symmetrically arranged about the center line of the dock 7.

[0050] The cable 5 is a steel wire rope with a diameter of 53 millimeters and a single length of 210 meters. For the convenience of description, the end of the cable 5 fixed on the steel caisson 6 is defined as a first end 51, and the other end is defined as a second end 52. Generally, the first end 51 is fixed on the drum of the winch 1, and the second end 52 is drawn out from the winch 1, passes through the turning saddle 3, and extends out from the steel caisson 6. As shown, Figure 1As shown, similar to the layout shown in the present embodiment, in some existing traction systems, multiple winches 1 are installed in the middle of the construction platform 62 to optimize the wiring of the power supply and simplify the configuration of the operators. In this way, the direction of the cable 5 winding and unwinding of the winch 1 cannot be collinear with the extension direction of the cable passage 35 on the turning saddle 3. In order to reduce the wear of the cable 5 and avoid the cable 5 from being stuck, the reversing wheel 2 is arranged near the intersection of the center line of the winch 1 and the turning saddle 3. The cable 5 from the winch 1 is partially wound on the reversing wheel 2, and the extension direction of the cable 5 is adjusted to the center line of the winch 1 and the turning saddle 3, thereby reducing the friction with the winch 1 and the turning saddle 3, and achieving smooth and stable operation of the traction system. It can be understood that due to the limitation of site conditions, the actual routing of the cable 5 does not completely coincide with the center line of the winch 1 and the turning saddle 3, but as long as the deflection angle is controlled within a reasonable range, it will not affect the actual operation of the traction system.

[0051] In order to move the steel caisson 6 in the extension direction of the dock 7, the second end 52 of the cable 5 extends from the turning saddle 3 to the mooring bitt 4 on the dock wall 72 on both sides. As shown in the figure, Figure 1 The second end 52 is provided with a ring-shaped rope ring 53 to quickly and stably connect with the shackle 43 on the mooring bitt 4. For the convenience of the following description, the direction of the steel caisson 6 towards the dock entrance 73 is defined as front, and the direction away from the dock entrance 73 is defined as back. The principle of the launching method is that when the steel caisson 6 is in a floating state, the front cable 5 is symmetrically connected with the two mooring bitts 4 on both sides in the direction of the steel caisson 6, and then the front winch 1 is started to simultaneously tighten the cable 5, so that the steel caisson 6 can be moved towards the dock entrance 73 by the principle of “action and reaction” between the dock wall 72 and the steel caisson 6. In this process, in order to prevent the rear of the steel caisson 6 from swinging, the rear cable 5 is symmetrically connected and tensioned with the two mooring bitts 4 behind the steel caisson 6, and at the same time the steel caisson 6 moves towards the dock entrance 73, the rear winch 1 is opened to slowly and synchronously loosen the cable 5. In this way, the tension on both sides of the steel caisson 6 is balanced, thereby avoiding the tail from swinging.

[0052] In combination with Figure 8The component numbering of the traction system is described below. In this embodiment, four traction systems are provided in the dock 7, namely traction system A, traction system B, traction system C, and traction system D. It should be understood that in other embodiments, the traction system may also have 6, 8, or more groups. In the launching direction of the steel caisson 6, traction systems A and B are located at the front of the construction platform 62, and are respectively located on the left and right sides of the construction platform 62; traction systems C and D are located at the rear of the construction platform 62, and are respectively located on the left and right sides of the construction platform 62. For traction system A, the components within the system are respectively labeled as: winch 1A, reversing wheel 2A, steering saddle 3A, and cable 5A. The component numbering of traction systems B, C, and D is the same as that of traction system A. In the direction of exiting the dock of the steel caisson 6, the mooring posts 4 on the left dock wall 72 are sequentially marked as L1, L2, L3, L4, L5... starting from the dock opening 73; the mooring posts 4 on the right dock wall 72 are sequentially marked as R1, R2, R3, R4, R5... starting from the dock opening 73.

[0053] The method will now be described in conjunction with the aforementioned hardware foundation and its designation. The method includes the following steps:

[0054] Step 1: Connect cable 5. (Example) Figure 8 As shown, on the front side of the steel caisson 6, connect cable 5A to shackle 43 on mooring post 4L1, and connect cable 5B to shackle 43 on mooring post 4R1; on the rear side of the steel caisson 6, connect cable 5C to shackle 43 on mooring post 4L6, and connect cable 5D to shackle 43 on mooring post 4R6. After all cables 5 are connected correctly, start each set of winches 1 to tighten the cables 5.

[0055] It should be explained that the cables 5C and 5D located on the rear side primarily serve to balance the lateral tension of the steel caisson 6. Their second ends 52 only need to be connected to the mooring posts 4 behind the steering saddles 3C and 3D, ensuring symmetrical connections on both sides. This will not affect subsequent water injection and buoyancy, or the movement of the steel caisson 6. Therefore, in other embodiments, the mooring posts 4 connected to cables 5C and 5D respectively should not be limited to L6 and R6. Corresponding to this step, in claim 1, the terms "front," "rear," "left," and "right" in step 1 refer to the direction of the steel caisson 6's departure from the dock.

[0056] Step 2: Water injection and floating. Water is injected into the dock chamber 71 until the water level reaches the predetermined level. During the water injection, the steel caisson 6 will gradually float up, so the difference between the top of the steel caisson 6 and the dock wall 72 is used to control the winch 1 to slowly release or wind the cable 5, so that the cable 5 is slightly tightened. At the same time, in order to make the steel caisson 6 have a stable moving path and posture during the floating, the center line of the steel caisson 6 is adjusted to coincide with the center line of the dock chamber 71 as much as possible.

[0057] In combination with step 2, it can be explained why the cable 5C and the cable 5D are not connected to the bollard 4 in front of the turning saddle 3C and the turning saddle 3D in step 1. If the cable 5C and the cable 5D are connected to the bollard 4 in front, the steel caisson 6 will move forward under the traction of the cable 5 during the water injection and floating. If the water level in the dock chamber 71 is not high, the bottom of the steel caisson 6 is prone to friction with the dock chamber 71 and structural damage.

[0058] Step 3: Traction and floating. When the water level in the dock chamber 71 reaches the predetermined level, the winch 1A and the winch 1B are started to synchronously tighten the cable 5A and the cable 5B at the same speed v1, and at the same time, the winch 1C and the winch 1D are started to synchronously release the cable 5C and the cable 5D at the same speed v2, so as to control the steel caisson 6 to move to the dock gate 73 at a speed not greater than 0.5 m / s. When the steel caisson 6 approaches the dock gate 73, the tightening speed of the cable 5A and the cable 5B and the releasing speed of the cable 5C and the cable 5D are controlled to slow down the steel caisson 6. When the steel caisson 6 reaches the dock gate 73 and stops moving, the cable 5 is tightened to stabilize the steel caisson 6.

[0059] Step 4: System transformation. When the steel caisson 6 waits for transportation at the dock gate 73, the operator needs to constantly start the winch 1 to adjust the posture of the steel caisson 6. At this time, the cable 5C and the cable 5D are long and have a small angle with the left and right sides of the steel caisson 6, so that the vertical component of the cable 5C and the cable 5D on the left and right sides of the steel caisson 6 is small under tension, which brings certain operation difficulty to stabilize the steel caisson 6. Therefore, in order to improve the stability of the steel caisson 6, the cable 5C and the cable 5D are connected to the closer bollard 4.

[0060] As shown in Figure 9 Two fiber ropes 8 are used to connect and tension the left and right sides of the steel caisson 6 to the bollard 4L3 and the bollard 4L4, respectively. Then, as shown in Figure 10As shown, the second end 52 of the cable 5C is released from the bitt 4L6 and replaced with the bitt 4L4; similarly, the second end 52 of the cable 5D is released from the bitt 4R6 and replaced with the bitt 4R4. After the cables 5C and 5D are symmetrically connected and tensioned, the fiber rope 8 is released, and the system transformation is completed. It should be understood that the fiber rope 8 is the auxiliary rope described in the claims.

[0061] Similarly, when replacing the connection points, the cables 5C and 5D can be connected with the bitts 4 close to and behind the turning saddles 3C and 3D. Therefore, in other embodiments, the cables 5C and 5D can be connected with the bitts 4L3 and 4L4, respectively.

[0062] Since the construction process of floating the steel caisson 6 by the tugboat is a common prior art and is not the focus of the present application, it will not be described here. At this point, the steel caisson 6 completes the construction of being launched.

[0063] In summary, the method provided by the embodiments of the present application uses the winch 1 carried by the steel caisson 6 to wind and unwind the cable 5 connected to the caisson wall 72, and uses the principle of “action and reaction” between objects to safely and stably pull the steel caisson forward and out of the dock. This method uses the self-contained traction system to replace the tugboat, cleverly avoiding the problem of lateral extrusion of the steel caisson 6 caused by improper main towing operation, limited space, etc. This method not only improves the safety of construction, but also reduces the cost of leasing.

[0064] Secondly, the at least four groups of traction systems cooperate at the four corners of the steel caisson 6 to control the precise movement of the steel caisson 6 in the four directions of front, back, left and right, and maintain dynamic balance. This method effectively solves the problem of left and right deviation and collision with the caisson wall 72 of the steel caisson 6 in a relatively narrow dock due to the abandonment of lateral auxiliary towing, and thus has high engineering applicability.

[0065] In addition, because this method can use the winch 1 to accurately control the caisson, the steel caisson 6 has higher braking performance when encountering an emergency or approaching the destination, which is lacking in most towing and launching methods.

[0066] Embodiment 2

[0067] As Figure 11As shown, the embodiment of the present application provides a large prefabricated structure undocking method based on self-owned traction system. The difference between the method provided in the embodiment 1 is that the hardware basis applied by the method is different. Specifically, the winch 1 is arranged on or near the center line of the turning saddle 3, and the winding and unwinding direction of the cable 5 is towards the turning saddle 3. Therefore, the traction system is not provided with the reversing wheel 2 and the matched second support, the fixing frame 21, so as to reverse the cable 5 between the winch 1 and the turning saddle 3.

[0068] In addition to the above difference, the rest of the method provided by the embodiment, including the specific undocking operation steps, is the same as the method provided in the embodiment 1.

[0069] The above is only the preferred specific embodiment of the present application, not the limitation of the patent range of the present application, and any technical equivalent transformation made by using the content of the present application is within the protection scope of the present application.

Claims

1. A method for launching a large precast structure based on a self-own traction system, characterized in that: Based on the following hardware basis: Dock, including dock chamber, dock wall, dock mouth; the dock wall extends on both sides of the dock chamber, and the dock mouth is located at one end of the dock chamber close to the water area; the prefabricated structure is located in the dock chamber and is docked out in the direction of the dock mouth; Towing system, including winch, turning saddle, a plurality of mooring bitts and cable; the winch is installed on the construction platform on the top of the prefabricated structure, used to wind and unwind the cable; the turning saddle is installed on the edge of the top of the prefabricated structure; the turning saddle is configured with a horn-shaped cable passing channel, and the horn mouth of the cable passing channel faces the outside of the prefabricated structure; the plurality of mooring bitts are installed on the top of the dock wall on both sides of the dock, and are arranged at intervals along the extension direction of the dock wall; the cable includes a first end and a second end, the first end is fixed to the winch, and the second end extends from the winch, passes through the cable passing channel of the turning saddle, and is finally connected with the mooring bitts; At least four groups of the towing system are arranged in the dock, including towing system A, towing system B, towing system C and towing system D; in the direction of the prefabricated structure out of the dock, the towing system A and the towing system B are arranged at the front of the construction platform and are respectively located on the left and right sides; the towing system C and the towing system D are arranged at the rear of the construction platform and are respectively located on the left and right sides; The method comprises the following steps: Step 1: connecting the cable; in the towing system A, the cable is connected with the left mooring bitt closest to the dock mouth; in the towing system B, the cable is connected with the right mooring bitt closest to the dock mouth; in the towing system C, the cable is connected with a mooring bitt behind and left of the turning saddle; in the towing system D, the cable is connected with a mooring bitt behind and right of the turning saddle; Step 2: water injection and floating; water is injected into the dock chamber until the water level height meets the dock-out condition; in the process of water injection, the winches of each group are started to wind and unwind the cables according to the height difference between the prefabricated structure and the top of the dock wall; Step 3: towing out of the dock; for the towing system A and the towing system B, the winches in the system are started to synchronously tighten the two cables in front, and at the same time, for the towing system C and the towing system D, the winches in the system are started to synchronously release the two cables behind, so as to tow the prefabricated structure to move to the dock mouth; Step 4: system transformation; At least two auxiliary ropes are used to connect and tension the left rear and right rear of the prefabricated structure with the adjacent mooring bitts respectively; then, in the towing system C, the second end of the cable is released from the original mooring bitt and connected to the adjacent mooring bitt behind and left of the turning saddle; in the towing system D, the second end of the cable is released from the original mooring bitt and connected to the adjacent mooring bitt behind and right of the turning saddle; further, the auxiliary ropes are released.

2. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: In step 3, when the prefabricated structure approaches the dock mouth, the winding speed of the winches in the towing system A and the towing system B and the unwinding speed of the winches in the towing system C and the towing system D are controlled to slow down the prefabricated structure.

3. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: In step 3, the moving speed of the prefabricated structure is not greater than 0.5 m / s.

4. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: In step 1, after the cables in each group of the traction system are connected correctly, start each group of winches to tighten the cables.

5. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: In step 2, when the prefabricated structure is floating, start each group of winches to coordinate the length of each group of cables to fine-tune the center line of the prefabricated structure to coincide with the center line of the dock.

6. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: In step 2, the top of the prefabricated structure is higher than the top of the dock wall; during the water injection process, start each group of winches to release each group of cables synchronously.

7. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: The winch has a direction of winding and unwinding the cable, which is different from the extension direction of the cable passage in the turning saddle; the traction system further comprises a reversing wheel; the reversing wheel is installed on the construction platform and located near the intersection of the center lines of the winch and the turning saddle; the reversing wheel has a rotational degree of freedom in the horizontal plane; after the cable is drawn out from the winch, it is partially wound around the reversing wheel and extends to the turning saddle.

8. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: The turning saddle comprises a bottom plate, side plates and a movable top plate; the bottom plate is trumpet-shaped and inclined or curved downward toward the trumpet mouth; two arc-shaped side plates are fixed to the left and right sides of the extension direction of the bottom plate and jointly form a trumpet-shaped cable passage with the top of the bottom plate; the two side plates and the bottom of the bottom plate form a support cavity, which is filled with concrete; the side plates are fixed with stiffening frames on the side away from the cable passage; the movable top plate is detachably connected to the top of the two stiffening frames to span above the cable passage.

9. A method for launching a large prefabricated structure based on a self- traction system according to claim 1, characterized in that: The traction system further comprises a rope sleeve and a shackle; the rope sleeve is sleeved on the bollard through the shackle; the shackle is openable; the second end of the cable is provided with a ring-shaped cable loop; in steps 1 to 3, the cable is connected to the bollard by threading the cable loop into the shackle.

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