Artificial island construction method by reclamation without cofferdam

Abstract

The present invention discloses a construction method for reclamation by hydraulic filling without cofferdam in artificial islands, which includes: setting up a pollution prevention screen outside the island construction area, and forming a north sandbank, an east sandbank, a south sandbank and a west sandbank by hydraulic filling in the island construction area; hydraulically filling inside the north sandbank to widen the top width of the north sandbank; laying sand blankets for the first time inside the east sandbank, the south sandbank and the west sandbank; concentrating hydraulic filling in the area enclosed by the sand blankets of the east sandbank, the south sandbank, the west sandbank laid for the first time and the north sandbank; laying sand blankets for the second time on the tops of the sand blankets of the east sandbank, the south sandbank and the west sandbank, and the sand blankets laid for the first time and the sand blankets laid for the second time jointly form a sand blanket cofferdam; concentrating hydraulic filling inside the sand blanket cofferdam; laying geotextiles, facing rubble, backfill cushion stones, backfill bottom protection stones, and installing fence panels. The present invention can not only prevent the construction inside the sandbank from polluting the open sea, but also provide a storage yard for sand materials nearby, and at the same time facilitate the construction of filling sand blankets.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial island construction. More specifically, the present invention relates to a method for reclamation by hydraulic filling without cofferdam for artificial islands. Background Art

[0002] In the subsequent planned dredging and backfilling project of Jazan Economic City in Saudi Arabia, the dredged surplus materials and unloading soil need to be discarded at the spoil ground designated by the owner, which is about 9 kilometers away from the project site. Moreover, the unqualified soil needs to be cleaned again. During the project implementation stage, in order to reduce the transportation distance, improve the construction efficiency of the cutter suction dredger and control the cost, our side combined the general layout of the project and the actual situation of the tight land use in the economic city, and proposed a plan to build an artificial island near the dredged soil, blowing the dredged surplus materials into the sea area north of the original land reclamation area to fill and build an artificial island. The owner can also obtain a larger land area for use. This not only avoids the problems of long blowing distance and low construction efficiency, but also realizes the reuse of the dredged materials, and provides additional port land for the owner. During the construction of the artificial island, due to the owner's adoption of American standard management requirements and relatively high construction environmental protection requirements, it is necessary to ensure that the water quality outside the artificial island meets the environmental protection requirements. At the same time, the given construction period is short. The existing artificial islands generally use steel pipe piles or steel sheet pile cofferdams to enclose the sea, and then use barges to transport earth and stone materials or use cutter suction dredgers for hydraulic filling. It is difficult to meet the construction period requirements. For this reason, our side proposed a method for reclamation by hydraulic filling without cofferdam for artificial islands, which can not only meet the construction period requirements but also meet the environmental protection requirements. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and provide at least the advantages described hereinafter.

[0004] Another object of the present invention is to provide a method for reclamation by hydraulic filling without cofferdam for artificial islands. By setting up a pollution prevention screen in the island building area, it can prevent the sand materials from escaping and polluting the sea area outside the island building area. By blowing the sand materials into the island building area to form a sand embankment, it can not only prevent the construction inside the sand embankment from polluting the outer sea, but also provide a storage yard for the sand materials nearby, and at the same time facilitate the construction of sand-filled geotextile bags.

[0005] To achieve these and other advantages in accordance with the present invention, there is provided a method for reclamation by hydraulic filling without cofferdam for artificial islands, which includes:

[0006] Step 1: Set up an anti-pollution screen around the island-building area. Use a cutter suction dredger to blow and fill sand materials into the island-building area. First, blow and fill to form the North Sand Dike close to the original breakwater, and then blow and fill in sequence to form the East Sand Dike, South Sand Dike, and West Sand Dike. The top elevations of the North Sand Dike, East Sand Dike, South Sand Dike, and West Sand Dike are above the water surface. During the blowing and filling process, determine the sediment diffusion range through bathymetric survey and detect the actual diffusion range to adjust the position of the blowing and filling pipe nozzle, so that the distance between the blowing and filling pipe nozzle and the boundary of the artificial island remains above the diffusion range. After the West Sand Dike and the North Sand Dike are closed, use an excavator or bulldozer to raise the elevation of all sand dikes to the design height, and set up a drainage outlet and a sluice box on the West Sand Dike, then remove the anti-pollution screen;

[0007] Step 2: Blow and fill along the inner side of the North Sand Dike to widen the top width of the North Sand Dike for the passage of mechanical equipment;

[0008] Step 3: Use a mattress laying barge to lay the first layer of sand mattresses on the inner sides of the East Sand Dike, South Sand Dike, and West Sand Dike in sequence. When laying the sand mattresses, the mattress laying barge extracts and fills sand from the corresponding sand dike and pours it into the sand mattresses. The first layer of sand mattresses has m layers, and the widths of the m layers of sand mattresses gradually decrease from bottom to top to form a trapezoid. The ends of adjacent sand mattresses in the extension direction of the sand dike overlap each other to prevent gaps from being left between the sand mattresses after the sand materials shrink;

[0009] Step 4: Concentrate the blowing and filling inside the area enclosed by the sand mattresses of the East Sand Dike, South Sand Dike, West Sand Dike laid for the first time and the North Sand Dike, so that the inside of this area is filled with sand materials;

[0010] Step 5: Use a mattress laying barge to lay the second layer of sand mattresses on the tops of the sand mattresses of the East Sand Dike, South Sand Dike, and West Sand Dike in sequence. When laying the sand mattresses, the mattress laying barge extracts and fills sand from the corresponding sand dike and pours it into the sand mattresses. The second layer of sand mattresses has n layers, and the widths of the n layers of sand mattresses gradually decrease from bottom to top to form a trapezoid. The sand mattresses laid for the first time and the sand mattresses laid for the second time jointly form a sand mattress cofferdam, and the outer sides of the sand mattresses laid for the first time facing the sand dike and the outer sides of the sand mattresses laid for the second time facing the sand dike form a common slope surface;

[0011] Step 6: Concentrate the blowing and filling inside the area enclosed by the sand mattresses of the East Sand Dike, South Sand Dike, and West Sand Dike laid for the second time and the North Sand Dike, so that the inside of this area is filled with sand materials;

[0012] Step 7: Lay geotextiles and armor blocks on the common slope surface and the tops of the sand mattresses laid for the second time in sequence. Then backfill sand materials inside the sand mattresses to the same height as the armor blocks. Next, continue to throw and fill armor blocks on the tops of the armor blocks to the design elevation. Then continue to backfill sand materials inside the sand mattresses to the design elevation;

[0013] Step 8: Throw and fill cushion stones on the armor blocks of the common slope surface and level them. Throw and fill bottom protection blocks at the toe of the common slope surface and level them. Then install cribbing plates on the surface of the cushion stones.

[0014] Preferably, the sand blanket is processed into a rectangle, the width of the sand blanket is increased by 3% margin compared to the designed width of the core of the sand blanket cofferdam, the filling thickness of the sand blanket is 60 - 80 cm, one side of the sand blanket is provided with multiple rows of filling cuffs communicating with the inside of the sand blanket, the diameter of the filling cuffs is 30 cm, and the length is 20 cm. Reinforcing straps are evenly spaced along the width direction at both ends of the sand blanket.

[0015] Preferably, the process of laying the sand blanket by a planking barge includes:

[0016] Using a positioning system and a detector to measure and recheck the seabed elevation of the sand blanket laying position;

[0017] Anchor and position the planking barge, then let the sand barge approach and tie it to the planking barge, and it will move with the movement of the planking barge during the construction process;

[0018] Flatten one end of the sand blanket wound on the drum of the planking barge on the deck of the planking barge, unwind the sand blanket so that the first row of filling cuffs at one end of the sand blanket is located on the slide plate beside the ship's side of the planking barge. Use the sand pump on the sand barge to extract the sand material of the sand embankment, and then insert the sand filling pipe into the filling cuff to fill the sand material extracted by the sand pump into the sand blanket;

[0019] After the sand blanket section where the first row of filling cuffs is located is filled, tie the first row of filling cuffs with a rope, and let it slide into the seabed by the self - weight of the sand blanket. Move the planking barge and the sand barge slightly along the extension direction of the sand embankment so that the second row of filling cuffs of the sand blanket is located on the slide plate, then insert the sand filling pipe into the second row of filling cuffs and start filling the sand material. After the sand blanket section where the second row of filling cuffs is located is filled, tie the second row of filling cuffs with a rope and let it slide into the seabed by the self - weight of the sand blanket. Repeat this process until the entire sand blanket is laid.

[0020] Preferably, the sand filling amount of the sand blanket is 75 - 85%. After each sand blanket is laid, use a measuring instrument to check the shape of the sand blanket. If obvious grooves are found and difficult to handle, fill them with sand bags.

[0021] Preferably, the laying method of the geotextile includes:

[0022] Wind the pre - sewn geotextile onto the drum of the square barge;

[0023] Use the positioning system to position the square barge at the toe position of the common slope surface, unwind the geotextile, and tie sand bags at the end of the geotextile and sink them into the sea;

[0024] Move the square barge towards the shore side of the sand blanket cofferdam to spread the geotextile, and tie heavy objects on the geotextile every 5 - 6 m to facilitate sinking.

[0025] Preferably, the installation method of the cribbing slab includes:

[0026] After the precast fence panels are completed, they are transported from the storage yard to the site and installed in an inclined lifting manner. The installation is carried out from the toe of the common slope to the top of the slope.

[0027] During the installation of the fence panels, underwater divers cooperate. The underwater divers transmit information to the water surface to direct the installation of the fence panels.

[0028] Precast concrete piers are placed at the toe and the top of the common slope respectively. The concrete piers at the bottom and the top of the slope are connected with wire ropes to form a control line along the slope direction.

[0029] Precast concrete piers are evenly spaced along the extension line of the toe of the common slope. Adjacent two concrete piers at the toe of the slope are connected with wire ropes to form a control line along the toe of the slope direction.

[0030] Precast trapezoidal blocks are evenly spaced between adjacent two concrete piers at the toe of the slope. Fence panels are installed on the slope side of adjacent two trapezoidal blocks, so that the trapezoidal blocks can position the fence panels and resist against the bottom of the fence panels to play a role in stabilizing the foot of the slope.

[0031] After the installation of the lower layer of fence panels is completed, riprap is immediately filled to the design elevation to prevent the fence panels from sliding unstably. While filling the riprap, the installation of the upper layer of fence panels is carried out simultaneously.

[0032] The present invention has at least the following beneficial effects: By setting up a pollution prevention screen in the island building area, it can prevent the sand and gravel from escaping and polluting the sea area outside the island building area. By blowing the sand and gravel into the island building area to form a sand dike, it can not only prevent the construction inside the sand dike from polluting the open sea, but also provide a storage yard for the sand and gravel nearby, and at the same time facilitate the construction of sand-filled bags. Compared with the existing construction methods of using steel pipe piles or steel sheet pile cofferdams for island building by reclamation, this application does not require pile foundation construction in the sea, only need to carry out blowing and paving operations, the construction difficulty is greatly reduced, the construction efficiency is greatly improved, the construction period is shortened, and it can meet the environmental protection requirements of the owner.

[0033] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a construction schematic diagram of Step 1 of the construction method for artificial island reclamation without cofferdam of the embodiment of the present invention;

[0035] Figure 2 It is a construction schematic diagram of Step 2 of the construction method for artificial island reclamation without cofferdam of the embodiment of the present invention;

[0036] Figure 3 It is a construction schematic diagram of Step 3 of the construction method for artificial island reclamation without cofferdam of the embodiment of the present invention;

[0037] Figure 4It is a construction schematic diagram of Step 4 of the artificial island reclamation construction method without cofferdam according to the embodiment of the present invention;

[0038] Figure 5 It is a construction schematic diagram of Step 5 of the artificial island reclamation construction method without cofferdam according to the embodiment of the present invention;

[0039] Figure 6 It is a construction schematic diagram of Step 7 of the artificial island reclamation construction method without cofferdam according to the embodiment of the present invention;

[0040] Figure 7 It is a construction schematic diagram of throwing and leveling cushion stones in Step 8 of the artificial island reclamation construction method without cofferdam according to the embodiment of the present invention;

[0041] Figure 8 It is a construction schematic diagram of installing fence plates on the surface of cushion stones in Step 8 of the artificial island reclamation construction method without cofferdam according to the embodiment of the present invention;

[0042] Figure 9 It is a top view structural schematic diagram of the sand quilt according to the embodiment of the present invention;

[0043] Figure 10 It is a front view structural schematic diagram of the sand quilt according to the embodiment of the present invention;

[0044] Figure 11 It is a top view structural schematic diagram of the mattress laying barge according to the embodiment of the present invention;

[0045] Figure 12 It is a construction schematic diagram of the mattress laying barge laying the sand quilt according to the embodiment of the present invention;

[0046] Figure 13 It is a construction schematic diagram of laying geotextiles according to the embodiment of the present invention;

[0047] Figure 14 It is a construction schematic diagram of arranging concrete piers according to the embodiment of the present invention. Detailed implementation manners

[0048] The following further elaborates the present invention in detail with reference to the accompanying drawings, so that those skilled in the art can implement it according to the description in the specification.

[0049] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation schemes are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained from commercial channels; in the description of the present invention, the orientation or positional relationship indicated by terms such as "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention.

[0050] The present invention provides a construction method for reclamation of artificial islands without cofferdams, which includes:

[0051] Step 1: Set up a pollution prevention screen outside the island building area, and use a cutter suction dredger to fill the sand into the island building area. First, fill and form the North Sand Dike close to the original breakwater, and then fill and form the East Sand Dike, South Sand Dike and West Sand Dike in sequence. The top elevations of the North Sand Dike, East Sand Dike, South Sand Dike and West Sand Dike are above the water surface. During the filling process, determine the sediment diffusion range through water depth measurement and detect the actual diffusion range to adjust the position of the filling pipe mouth so that the distance between the filling pipe mouth and the boundary of the artificial island remains above the diffusion range. After the West Sand Dike and the North Sand Dike are closed, use an excavator or a bulldozer to raise the elevation of all sand dikes to the designed height, and set a water discharge port and a sluice box on the West Sand Dike, and remove the pollution prevention screen;

[0052] Specifically, fill and form a sand cofferdam with a top height of 2.5 m above the water surface inside the pollution prevention screen. The filling is carried out in the order of 1→2→3→4 as shown in Figure 1 . During the filling process, detect the natural slope ratio formed by the sand dike under the action of wind and waves to determine the shortest distance between the sand dike and the revetment structure on the premise of not affecting the construction base of the revetment. Through actual measurement and monitoring, the filling port needs to be 200 m away from the inner side of the bottom of the revetment, and the slope of the water outlet filling is about 1:20. During the filling process, it is necessary to monitor the water depth on site in real time according to the filling progress.

[0053] Step 2: Fill and widen the top width of the North Sand Dike along the inner side of the North Sand Dike to provide passage for mechanical equipment;

[0054] Specifically, as shown in Figure 2 , widen the sand dike along the range of the No. 1 Sand Dike on the inner side of the sand dike so that the top width is about 15 m, which can provide passage for mechanical equipment.

[0055] Step 3: Use a mattress-laying barge to lay sand mattresses for the first time inside the inner sides of the East Sand Dike, South Sand Dike, and West Sand Dike respectively. When laying the sand mattresses, the mattress-laying barge extracts and fills sand from the corresponding sand dikes and pours it into the sand mattresses. The sand mattresses laid for the first time have m layers, and the width of the m-layer sand mattresses gradually decreases from bottom to top to form a trapezoid. The ends of two adjacent sand mattresses in the extension direction of the sand dike overlap with each other to prevent gaps from being left between the sand mattresses after the shrinkage of the sand material, as Figure 3 shown;

[0056] Specifically, the sand mattresses laid for the first time are filled to 2.5 m below the water surface. Since the elevation of the natural seabed mud surface at the construction site is -5.5 to -7 m, the number of sand mattress layers required for each section of the sand mattress dike and the width of the bottom sand mattress also gradually change. Taking the original mud surface elevation of -6.5 as an example, the width of the first-layer sand mattress is about 20 m, the height is about 0.6 m, and 7 layers of sand mattresses are required to be laid to -2.5 m.

[0057] Step 4: Concentrate the hydraulic filling inside the area enclosed by the sand mattresses of the East Sand Dike, South Sand Dike, and West Sand Dike laid for the first time and the North Sand Dike, so that the inside of this area is filled with sand material, as Figure 4 shown;

[0058] Specifically, after the sand mattresses laid for the first time are completed, the hydraulic filling can be concentrated inside the area enclosed by the sand mattresses and the North Sand Dike. At the same time, since an inverted triangular depression area will be formed between the sand mattresses and the hydraulic filling sand, an open-body barge can be used to level this depression area.

[0059] Step 5: Use a mattress-laying barge to lay sand mattresses for the second time on the tops of the sand mattresses of the East Sand Dike, South Sand Dike, and West Sand Dike respectively. When laying the sand mattresses, the mattress-laying barge extracts and fills sand from the corresponding sand dikes and pours it into the sand mattresses. The sand mattresses laid for the second time have n layers, and the width of the n-layer sand mattresses gradually decreases from bottom to top to form a trapezoid. The sand mattresses laid for the first time and the sand mattresses laid for the second time together form a sand mattress cofferdam, and the outer sides of the sand mattresses laid for the first time facing the sand dike and the outer sides of the sand mattresses laid for the second time facing the sand dike form a common slope surface, as Figure 5 shown;

[0060] Specifically, the sand mattresses laid for the second time are filled from 2.5 m below the water surface to 1 m above the water surface, and about 6 layers of sand mattresses are required. The number of sand mattress layers and other factors can be adjusted according to the actual situation on site.

[0061] Step 6: Concentrate the hydraulic filling inside the area enclosed by the sand mattresses of the East Sand Dike, South Sand Dike, and West Sand Dike laid for the second time and the North Sand Dike, so that the inside of this area is filled with sand material;

[0062] Step 7: Lay geotextiles and armor blocks on the common slope surface and the tops of the sand mattresses laid for the second time in sequence. Then, backfill sand material inside the sand mattresses to the same height as the armor blocks. Next, continue to dump armor blocks on the tops of the armor blocks until the design elevation is reached. Then, continue to backfill sand material inside the sand mattresses until the design elevation is reached, asFigure 6 as shown;

[0063] Step Eight: Fill and level the cushion stone on the co-planar surface of the facing stones, fill and level the bottom protection stones at the toe of the co-planar slope, and then install the fence plates on the surface of the cushion stone, as Figures 7 - 8 shown.

[0064] During the construction process of the above embodiments, by setting up a pollution prevention screen in the island building area, the escape of sand materials can be prevented from polluting the sea area outside the island building area. By blowing the sand materials into the island building area to form a sand embankment, it can not only prevent the construction inside the sand embankment from polluting the open sea, but also provide a nearby storage yard for the sand materials, and at the same time facilitate the construction of the sand-filled geotextile bags. Compared with the existing construction methods of using steel pipe piles or steel sheet pile cofferdams for island building by reclamation, this application does not require pile foundation construction in the sea, only requires filling and laying operations, greatly reducing the construction difficulty, greatly improving the construction efficiency, shortening the construction period, and meeting the environmental protection requirements of the owner.

[0065] In another embodiment, the geotextile bag is processed into a rectangle, the width of the geotextile bag is 3% more than the designed width of the core of the geotextile bag cofferdam, the filling thickness of the geotextile bag is 60 - 80 cm, one side of the geotextile bag is provided with multiple rows of filling cuffs communicating with the inside of the geotextile bag, the diameter of the filling cuff is 30 cm, and the length is 20 cm. Reinforcing belts are evenly spaced along the width direction at both ends of the geotextile bag, as Figures 9 - 10 shown.

[0066] Specifically, the geotextile bag uses 200 g / m 2 polypropylene woven fabric, which is an anti-aging material. The specification performance is shown in Table 1 below:

[0067] Table 1

[0068]

[0069] Note: 1. The indicators marked with "*" in the table are the indicators that must be achieved, and the allowable deviation of the remaining indicators is -5%;

[0070] The geotextile bags are spliced and sewn by the overlock method. The splicing part is folded in three layers with a width of 5 - 10 cm and sewn three times with a 35 - strand three - ply nylon thread industrial sewing machine (sew one first, then fold and sew two more). It is required that the sewing is firm and its strength is not less than 90% of the original fabric design strength. The distance between the threads is uniform, preferably controlled at about 1 cm. The sewing thread should be of uniform tightness, and the stitch spacing should be 12 - 13 stitches / 10 cm. Skipping stitches are prohibited. There should not be too many splicing seams on each geotextile bag, and the distance between adjacent splicing seams should be greater than 2 m. There are no splicing seams on the exposed part after the cross - section is formed. Considering that the longitudinal stagger seam of the geotextile bag is not less than 3 m, special - shaped bags need to be made for each layer according to the actual situation to meet the stagger seam requirements. As the cross - section of the upper - layer geotextile bag becomes smaller, the longitudinal production length increases accordingly.

[0071] The cuff is arranged on the surface of the sand quilt, and the cuff material is 150 g / m 2 woven fabric with a spacing of 3.5×3.5 m or adjusted accordingly according to the actual situation. The reinforcing belt uses a 5-cm-wide polypropylene reinforcing belt, and it is required to be sewn at least 2 times with a stitch pitch less than 10 mm.

[0072] After the sand quilt is sewn, it is folded into shape, stacked in a cool and dry place, and the size and filling position of the sand bag are marked. Geotextiles with a storage period exceeding 6 months or showing signs of aging and damage shall not be used.

[0073] In another embodiment, the paving ship is as Figure 11 shown, and there are drums, a winch for driving the drums, a skateboard hinged to the ship's side, a hanging bracket arranged on the deck, a cable passing around the hanging bracket for lifting and pulling the skateboard, and a winch connected to the cable for driving the skateboard to flip on the deck of the paving ship.

[0074] The process of laying the sand quilt using the paving ship includes:

[0075] Measuring and rechecking the seabed elevation of the sand quilt laying position using a positioning system and a detector;

[0076] Anchoring and positioning the paving ship, and then bringing the sand barge close and tying it to the paving ship, and it will move with the movement of the paving ship during the construction process;

[0077] Flatten one end of the sand quilt wound on the drum on the paving ship deck, unwind the sand quilt so that the first row of filling cuffs at one end of the sand quilt is located on the skateboard at the ship's side of the paving ship. Use the sand pump on the sand barge to extract the sand material from the sand bank, and then insert the sand filling pipe into the filling cuff to fill the sand material extracted by the sand pump into the sand quilt;

[0078] After the sand quilt section where the first row of filling cuffs is located is filled, tie the first row of filling cuffs with a rope, and let it slide into the seabed by the weight of the sand quilt. Move the paving ship and the sand barge slightly along the extension direction of the sand bank so that the second row of filling cuffs of the sand quilt is located on the skateboard, then insert the sand filling pipe into the second row of filling cuffs and start filling the sand material. After the sand quilt section where the second row of filling cuffs is located is filled, tie the second row of filling cuffs with a rope and let it slide into the seabed by the weight of the sand quilt. Repeat this cycle until the entire sand quilt is laid, as Figure 12 shown.

[0079] During the specific construction process, the sand filling amount of the sand quilt is 75 - 85%. After each sand quilt is laid, use a measuring instrument to check the shape of the sand quilt. If obvious grooves are found and difficult to handle, fill them with sand bags.

[0080] For each newly laid sandbag layer, it should overlap with the completed sandbags by 0.2 - 0.3 meters to prevent large gaps from remaining between the sandbags after the sand material shrinks. During the construction process, the filled sandbags are frequently measured to master the actual position, elevation, and slope formation of the sandbags and guide the smooth progress of the construction.

[0081] The construction control standards for the sand-filled cofferdam are shown in Table 2 below:

[0082] Table 2

[0083]

[0084] In the above embodiments, the sand-filled bags are integrally sewn to combine the sandbags into one to form a bagged sand-filled structure, reducing the gaps between the sandbags. The formed sand-filled cofferdam is denser. At the same time, compared with the original single sandbag, the weight of the sand-filled bag after filling with sand material far exceeds that of the single sandbag. Therefore, the ability to resist water flow scouring is stronger, and the probability of displacement after the formation of the sand-filled cofferdam decreases. In addition, during the construction of the sand-filled bag, the structure construction can be completed through one-time positioning without multiple positionings, and the filling and laying of the sand-filled bag are continuously constructed, with high construction efficiency.

[0085] As Figure 13 shown, in another embodiment, the laying method of the geotextile includes:

[0086] Wind the pre-sewn geotextile around the drum of the barge;

[0087] Use the positioning system to position the barge at the toe position of the common slope surface, unwind the geotextile, and tie sandbags to the end of the geotextile and sink them into the sea;

[0088] Move the barge towards the shore side of the sand-filled cofferdam for spreading, and tie heavy objects to the geotextile every 5 - 6 m to facilitate sinking.

[0089] In Step 7, after the geotextile is towed to the shore and covers the surface of the sandbag, leave enough length, and carry out the construction of the facing riprap above the sand-filled bag. After the first riprap construction reaches +1.64 m CD, tighten the geotextile against the riprap slope surface, and backfill the sand behind to the same elevation. Then, carry out the second riprap construction to +2.5 m CD, tighten the geotextile against the riprap slope surface again, and backfill the sand behind to +2.5 m CD before completing the geotextile construction to form the final construction section as Figure 6 shown.

[0090] In another embodiment, the installation method of the cribbing slab includes:

[0091] After the cribbing slab is precast, it is transported from the storage yard to the site and installed by the inclined lifting method. The installation is carried out from the toe of the common slope surface to the slope top. The bottom layer is installed by a 150-ton crane, and the top layer can be installed by an 80-t crane;

[0092] There are two sizes of the fence panels: 3.75*3m and 3.25*3m. When prefabricating, first prefabricate the fence panels of 3.25*3m. After the prefabrication of the fence panels of this size is completed, extend the bottom formwork and the side formwork to prefabricate the fence panels of 3.75*3m. The dimensional accuracy requirements of the fence panels are shown in Table 3 below:

[0093] Table 3

[0094]

[0095] When installing the fence panels, underwater divers are coordinated. The underwater divers transmit information to the water surface to direct the installation of the fence panels;

[0096] Place the precast concrete piers at the toe and the top of the common slope surface. Connect the concrete piers at the bottom and the top of the slope with wire to form a control line along the slope direction;

[0097] Place the precast concrete piers at equal intervals along the extension line of the toe of the common slope surface. Connect the adjacent two concrete piers at the toe of the slope with wire to form a control line along the toe of the slope direction;

[0098] Place the precast trapezoidal blocks at equal intervals between the adjacent two concrete piers at the toe of the slope. Install the fence panels on the slope side of the adjacent two trapezoidal blocks so that the trapezoidal blocks position the fence panels and resist the bottom of the fence panels to play a role in stabilizing the foot, as Figure 14 shown;

[0099] After the installation of the lower layer of fence panels is completed, immediately backfill the protective riprap to the design elevation to prevent the fence panels from sliding unstably. While backfilling the stones, install the upper layer of fence panels, as Figure 8 shown.

[0100] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A construction method for reclamation by hydraulic filling without cofferdam for artificial islands, characterized in that Including: Step 1: Set up an anti-pollution screen around the island-building area. Use a cutter suction dredger to blow and fill sand materials into the island-building area. First, blow and fill to form the North Sand Dike close to the original breakwater, and then blow and fill in sequence to form the East Sand Dike, South Sand Dike, and West Sand Dike. The top elevations of the North Sand Dike, East Sand Dike, South Sand Dike, and West Sand Dike are above the water surface. During the blowing and filling process, determine the sediment diffusion range through bathymetric measurement and detect the actual diffusion range to adjust the position of the blowing and filling pipe orifice, so that the distance between the blowing and filling pipe orifice and the artificial island boundary remains above the diffusion range. After the West Sand Dike and the North Sand Dike are closed, use an excavator or bulldozer to raise the elevation of all sand dikes to the design height, and set a water discharge port and a sluice box on the West Sand Dike, then remove the anti-pollution screen; Step 2: Blow and fill along the inner side of the North Sand Dike to widen the top width of the North Sand Dike for mechanical equipment to pass; Step 3: Use a mattress laying barge to lay sand mattresses for the first time on the inner sides of the East Sand Dike, South Sand Dike, and West Sand Dike in sequence. When laying the sand mattresses, the mattress laying barge extracts and fills sand from the corresponding sand dike and pours it into the sand mattresses. The sand mattresses laid for the first time have m layers, and the widths of the m-layer sand mattresses gradually decrease from bottom to top to form a trapezoid. The ends of adjacent sand mattresses in the sand dike extension direction overlap each other to prevent voids from being left between the sand mattresses after the sand materials shrink; Step 4: Blow and fill intensively inside the area enclosed by the sand mattresses of the East Sand Dike, South Sand Dike, West Sand Dike laid for the first time and the North Sand Dike, so that the inside of this area is filled with sand materials; Step 5: Use a mattress laying barge to lay sand mattresses for the second time on the tops of the sand mattresses of the East Sand Dike, South Sand Dike, and West Sand Dike in sequence. When laying the sand mattresses, the mattress laying barge extracts and fills sand from the corresponding sand dike and pours it into the sand mattresses. The sand mattresses laid for the second time have n layers, and the widths of the n-layer sand mattresses gradually decrease from bottom to top to form a trapezoid. The sand mattresses laid for the first time and the sand mattresses laid for the second time jointly form a sand mattress cofferdam, and the outer sides of the sand mattresses laid for the first time facing the sand dikes and the outer sides of the sand mattresses laid for the second time facing the sand dikes form a common slope surface; Step 6: Blow and fill intensively inside the area enclosed by the sand mattresses of the East Sand Dike, South Sand Dike, West Sand Dike laid for the second time and the North Sand Dike, so that the inside of this area is filled with sand materials; Step 7: Lay geotextiles and armor stones on the common slope surface and the tops of the sand mattresses laid for the second time in sequence. Then backfill sand materials inside the sand mattresses to the same height as the armor stones. Next, continue to throw and fill armor stones on the tops of the armor stones to the design elevation. Then continue to backfill sand materials inside the sand mattresses to the design elevation; Step 8: Throw and fill cushion stones on the armor stones of the common slope surface and level them. Throw and fill bottom protection stones at the foot of the common slope surface and level them. Then install cribbing plates on the surface of the cushion stones.

2. The artificial island reclamation construction method without cofferdam as claimed in claim 1, wherein, The sand mattress is processed into a rectangle. The width of the sand mattress is the designed width of the sand mattress cofferdam core plus a 3% margin. The filling thickness of the sand mattress is 60 - 80 cm. One side of the sand mattress is provided with multiple rows of filling cuffs communicating with the inside of the sand mattress. The diameter of the filling cuffs is 30 cm and the length is 20 cm. Reinforcing belts are evenly spaced along the width direction at both ends of the sand mattress.

3. The method for constructing artificial island by reclamation without cofferdam according to claim 2, characterized in that, The process of laying sand mattresses using a mattress laying barge includes: Using a positioning system and a detector to measure and review the seabed elevation of the sand mattress laying position; Anchor the laying ship and then bring the sand barge close to it and tie it together with the laying ship. During the construction process, the sand barge moves with the movement of the laying ship. One end of the sand blanket wound on the drum on the laying ship is flattened on the deck of the laying ship, and the sand blanket is unwound so that the first row of filling cuffs at one end of the sand blanket is located on the slide plate on the side of the laying ship. The sand pump on the sand barge is used to extract sand from the sand bank, and then the sand filling pipe is inserted into the filling cuff to fill the sand pumped by the sand pump into the sand blanket; After the sand quilt section where the first row of filling cuffs are located is filled, tie the first row of filling cuffs with ropes, and let the sand quilt slide to the seabed with its own weight. Move the laying ship and sand barge a little along the extension direction of the sand bank so that the second row of filling cuffs of the sand quilt are located on the slide, and then insert the sand filling pipe into the second row of filling cuffs and start filling with sand. After the sand quilt section where the second row of filling cuffs are located is filled, tie the second row of filling cuffs with ropes, and let the sand quilt slide to the seabed with its own weight. Repeat this cycle until the entire sand quilt is laid.

4. The method for constructing artificial island by reclamation without cofferdam according to claim 3, characterized in that The sand filling amount of the sand blanket is 75-85%. After each sand blanket is laid, the shape of the sand blanket is checked with a measuring instrument. If obvious grooves are found that are difficult to handle, sand bags are used to fill them.

5. The artificial island reclamation construction method without cofferdam as claimed in claim 1, wherein, The laying method of the geotextile comprises: Wind the pre-sewn geotextile onto the drum of the barge; Use the positioning system to position the barge at the foot of the common slope, unroll the geotextile, tie sandbags at the end of the geotextile and sink it into the sea; Move the square barge toward the bank of the sand cofferdam and spread it out, and tie heavy objects on the geotextile every 5 to 6 meters to facilitate sinking.

6. The artificial island reclamation construction method without cofferdam according to claim 1, characterized in that, The installation method of the fence panel includes: After the fence panels are prefabricated, they are transported from the yard to the site and installed by inclined hanging from the foot of the slope to the top of the slope. The fence panels are installed with the cooperation of underwater divers, who transmit information to the surface and direct the installation of the fence panels; Prefabricated concrete piers are placed at the foot and top of the common slope, and the concrete piers at the bottom and top of the slope are connected with lead wire to form a control line along the slope direction; Prefabricated concrete piers are placed evenly spaced along the slope foot extension line of the common slope surface. Two adjacent concrete piers on the slope foot are connected with lead wire to form a control line along the slope foot direction; Place prefabricated trapezoidal blocks evenly between two adjacent concrete piers at the foot of the slope, and install fence panels on the slope side of two adjacent trapezoidal blocks, so that the trapezoidal blocks can position the fence panels and press against the bottom of the fence panels to stabilize the feet; After the installation of the lower fence board is completed, immediately throw the guard stone to the designed elevation to prevent the fence board from becoming unstable and sliding down. While throwing the stone, install the upper fence board.

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