Obstacle-clearing and hole-fixing structure and construction method of support piles for soft land-sea alternating reclamation

Abstract

The present invention discloses a support pile clearing and fixing hole structure and construction method for soft land-sea interactive reclamation geology. The clearing and fixing hole structure includes a plurality of fixed holes formed by a pile skipping construction method. Adjacent fixed holes partially overlap. The fixed holes extend downward through an artificial fill layer and a reclamation layer to the lower layer of the soft land-sea interactive geology. The positions of the fixed holes are aligned one by one with the positions of the support piles. A fixing hole wall is provided on the inner wall of the fixing hole. The fixing hole wall is made of silicate cement dry-mixed mud. The formation process of the fixing hole wall is limited and shaped by a casing. A concrete guide wall is laid on the upper plane of the soft land-sea interactive reclamation geology. Positioning holes are formed on the concrete guide wall corresponding to the positions of the fixing holes. The construction method of the present invention utilizes the above-mentioned support pile clearing and fixing hole structure for soft land-sea interactive reclamation geology. The present invention can avoid problems such as hole collapse, pipe burst, and diameter shrinkage, and can ensure the verticality of the pile hole of the support pile.

Description

Technical Field

[0001] The present invention relates to the construction of support piles, and in particular to an obstacle-clearing and hole-fixing structure of support piles in soft land-sea alternating reclamation geology and a construction method thereof. Background Art

[0002] In the soft land-sea interaction reclamation geology, the upper layer 101 is generally composed of artificial fill, silty soil, silt, silty clay, silty fine sand, medium-coarse sand, gravel sand, etc.; the middle layer 102 is generally composed of crushed soil, crushed stone, pebble layer, small boulders, waste pile heads and reclamation construction waste and other obstacles; the lower layer 103 is generally composed of thick soft sea silt, silty soil, loose sand, etc. Figure 1 The diagram shows a weak land-sea reclamation geology. This type of geology typically has insufficient bearing capacity, uneven foundation soil, poor permeability, high porosity, high plasticity index, slow natural consolidation rate, and high compressibility. The soil is unevenly distributed over a depth of 30-90 meters. The lowest bedrock is exposed as strongly, moderately, and slightly weathered rock.

[0003] In this type of geology, due to the abundance of groundwater, "pipe bursts" will occur. During the process of driving the supporting pile holes, if the holes are not filled and fixed in time, the groundwater will carry the soft mud on the upper and lower wall layers of the pile holes to refill the hole diameter, and the middle layer of land reclamation construction waste, crushed stone, pebble layer, small boulders and other waste materials will cause the hole to collapse, causing the pile to shrink.

[0004] If the weak foundation is not solidified and filled, it can cause the pile driver to tilt, the pile hole to be skew, bend, shrink, collapse, or slurry leaking around the casing, as well as ground subsidence, during the later stages of pile foundation construction. Furthermore, the presence of waste pile heads, reclamation construction waste, small boulders, crushed soil, gravel, and pebbles in the middle of the stratum can cause drill bit sticking, bit breakage, and bit dropout, causing equipment damage and delays. Therefore, research on the clearing and hole-fixing structure and method technology for soft land-sea interactive reclamation geological support piles can avoid pile foundation accidents, be scientific and safe, energy-saving and environmentally friendly, ensure quality and safety, and save construction time. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a soft land-sea alternating land reclamation geological support pile obstacle clearing and hole fixing structure.

[0006] The second technical problem to be solved by the present invention is to provide a method for constructing support piles using the above-mentioned soft land-sea interactive reclamation geological support pile obstacle clearing and hole fixing structure.

[0007] The present invention can avoid problems such as hole collapse, pipe burst, diameter shrinkage, etc., and can ensure the verticality of the pile hole of the supporting pile.

[0008] To solve the above-mentioned first technical problem, the technical solution adopted by the present invention is as follows:

[0009] A support pile obstacle clearance and hole fixing structure for soft land-sea interactive reclamation geology is characterized by: comprising a plurality of solidified holes formed by a pile skipping construction method, with adjacent solidified holes partially overlapping, and the solidified holes extending downward to the lower layer of the soft land-sea interactive reclamation geology, the positions of the solidified holes being aligned one by one with the positions of the support piles, a solidified hole wall being provided on the inner wall of the solidified hole, the material of the solidified hole wall being silicate cement dry-mixed mud, the formation process of the solidified hole wall being limited and shaped by a casing, a concrete guide wall being laid on the upper plane of the soft land-sea interactive reclamation geology, and positioning holes being formed on the concrete guide wall corresponding to the positions of the solidified holes.

[0010] Optionally, the bottom of the solidified hole is more than 1 meter lower than the middle layer of the weak sea-land interactive reclamation geology.

[0011] Optionally, the thickness of the concrete guide wall is 0.4 meters.

[0012] To solve the above second technical problem, the technical solution adopted by the present invention is as follows:

[0013] A method for constructing support piles using the above-mentioned soft land-sea alternating reclamation geological support pile obstacle clearing and hole fixing structure is characterized by comprising the following steps:

[0014] Step 1: Press the first casing into the location of the solidified hole, remove the objects in the first casing, then backfill the first casing with Portland cement dry mix mud, and then remove the first casing to complete the clearing and backfilling of a solidified hole;

[0015] Step 2: Repeat step 1 and follow the pile skipping construction method to complete the clearing and backfilling of all the solidification holes in sequence. After that, all the solidification holes are filled with Portland cement dry mix mud;

[0016] Step 3: Lay a concrete guide wall on the upper plane of the soft land-sea interaction reclamation geology, and form positioning holes on the concrete guide wall at the positions corresponding to the solidification holes;

[0017] Step 4: At the location of the solidification hole, press in the second casing along the positioning hole. The diameter of the second casing is smaller than that of the first casing. The object in the second casing is dug out and then the second casing is removed to form a solidification hole. A solidification hole wall is formed on the inner wall of the solidification hole.

[0018] Step 5: Repeat step 4 and complete all the solidification holes in sequence according to the pile skipping construction method;

[0019] Step 6: Then construct support piles at the location of the solidified holes. According to the skipping pile construction method, complete the support piles at the locations of all solidified holes in sequence.

[0020] Optionally, the cement content in the silicate cement dry mix slurry is 8%.

[0021] Optionally, in step 1, the center line of the first casing coincides with the center line of the corresponding supporting pile, and the bottom surface of the hole formed by digging out the object in the first casing is smoothed.

[0022] Optionally, in step one, the bottom surface of the hole formed by excavating in the first casing is more than 1 meter lower than the middle layer of the weak sea-land interactive reclamation geology.

[0023] Optionally, the supporting piles include plain concrete supporting piles and reinforced concrete supporting piles, and the plain concrete supporting piles and reinforced concrete supporting piles are arranged alternately in sequence.

[0024] Optionally, in step one, the bottom surface of the first casing is not less than 2.5 m from the excavation surface during excavation.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention removes obstacles such as crushed stone, pebble layers, small boulders, waste pile heads and construction waste in artificial land reclamation in soft sea-land interactive land reclamation geology, providing a guarantee for the smooth construction of support piles. Solidified holes are first formed at the positions of the support piles, which can avoid problems such as hole collapse, pipe bursts, and diameter shrinkage, ensure the verticality of the pile holes of the support piles, and ensure that the subsequent interlocking pile casing construction can smoothly pass through the stone filling layer to form holes and take soil. The use of the skip pile construction method can prevent the pile hammer from slipping into the adjacent holes that have been completed.

[0027] 2. The present invention solves the problem of "piping burst" and prevents problems such as hole collapse and diameter shrinkage during pile construction.

[0028] 3. The present invention provides a concrete guide wall with positioning holes on it, so that the gap between the casing and the positioning holes remains uniform, solving problems such as unbalanced equipment construction caused by insufficient foundation bearing capacity and unstable foundation, and ensuring the positioning and verticality of the pile hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the upper, middle and lower layers of the weak sea-land interactive reclamation geology;

[0030] Figure 2 Schematic diagram of the obstacle removal and hole fixing structure after backfilling with Portland cement dry mix slurry according to the present invention;

[0031] Figure 3 It is a schematic diagram of the construction sequence of the pile jumping construction method of the present invention;

[0032] Figure 4 This is a schematic diagram of the distribution of pile hole bite connections;

[0033] Figure 5 is a schematic top view of a concrete guide wall of the present invention;

[0034] Figure 6 yes Figure 5 Schematic diagram of the cross section at NN in the middle;

[0035] Figure 7 It is a schematic diagram of the excavation process in the present invention;

[0036] Figure 8 It is a schematic diagram of the process of digging out the object in the second casing in the present invention;

[0037] Figure 9 It is a top view schematic diagram of the final structure of the present invention;

[0038] Figure 10 This is a schematic diagram of the final alternating plain concrete support piles and reinforced concrete support piles.

[0039] Meaning of the reference numerals in the figure:

[0040] 1-solidified hole; 2-solidified hole wall; 3-concrete guide wall; 4-first casing; 5-portland cement dry mix mud; 6-second casing; 7-grab bucket; 8-positioning hole; 9-reinforced concrete support pile; 10-plain concrete support pile; 101-upper layer; 102-middle layer; 103-lower layer. DETAILED DESCRIPTION

[0041] The present invention is further described below with reference to the embodiments.

[0042] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0043] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0044] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0045] Example:

[0046] In this embodiment, a support pile obstacle removal and fixing structure for soft land-sea interaction landfill includes multiple fixed holes 1 formed using a skip pile construction method. The multiple fixed holes 1 are arranged sequentially, with adjacent fixed holes 1 partially overlapping. The fixed holes 1 pass through artificial fill layers and landfill layers to the lower layer 103 of the soft land-sea interaction landfill, thereby clearing obstacles such as artificially reclaimed gravel, pebbles, small boulders, abandoned pile heads, and construction waste in the soft land-sea interaction landfill. The positions of the fixed holes 1 are aligned with the positions of the support piles to be produced, with the centers of the fixed holes 1 coinciding with the centers of the support piles. Fixed hole walls 2 are provided on the inner walls of the fixed holes 1. The fixed hole walls 2 are made of Portland cement dry mix slurry. The formation of the fixed hole walls 2 is limited and shaped by casing. A concrete guide wall 3 is laid on the upper surface of the soft land-sea interaction landfill, with positioning holes 8 formed on the concrete guide wall 3 corresponding to the positions of the fixed holes.

[0047] like Figure 3 The figure shows a schematic diagram of the pile skipping construction method, which is carried out in the order of hole a, hole b, hole c, hole d, hole e... In the figure, hole b is carried out by skipping hole c in the middle, and hole c is carried out between holes a and b. Figure 4 It is a schematic diagram of the distribution of the formed pile hole bite connection.

[0048] The bottom of the solidified hole 1 is more than 1 meter lower than the middle layer of the soft land-sea interactive reclamation geology, and the thickness of the concrete guide wall 3 is 0.4 meters.

[0049] This embodiment also discloses a method for constructing support piles using the above-mentioned soft land-sea alternating land reclamation geological support pile obstacle clearing and hole fixing structure, which includes the following steps:

[0050] Step 1: Press the first casing 4 into the position of the solidified hole 1, and dig out the objects in the first casing 4, so as to remove obstacles such as crushed stone, pebble layer, small isolated stone, waste pile head and construction waste in the soft land-sea interactive reclamation geology. The center line of the first casing 4 coincides with the center line of the corresponding support pile. The bottom surface of the hole formed by digging out the objects in the first casing 4 is smoothed. The bottom surface of the hole formed by digging in the first casing 4 is more than 1 meter lower than the middle layer of the soft land-sea interactive reclamation geology. The bottom surface of the first casing 4 is not less than 2.5m away from the excavation surface during excavation. Then, backfill the first casing 4 with silicate cement dry-mixed mud 5, limit and shape it through the first casing 4, and then take out the first casing 4, thereby completing the obstacle removal and backfilling of a solidified hole. Figure 2 As shown;

[0051] Step 2: Repeat step 1 and follow the pile skipping construction method to complete the clearing and backfilling of all the solidification holes in sequence. After that, all the solidification holes are filled with Portland cement dry mix mud;

[0052] Step 3: Lay a concrete guide wall 3 on the upper plane of the soft land-sea interactive reclamation geology, and form positioning holes 8 on the concrete guide wall 3 at the positions corresponding to the solidification holes. The solidification holes are located in the middle of the concrete guide wall, such as Figure 5 and Figure 6 As shown;

[0053] Step 4: At the location of the solidified hole, press in the second casing 6 along the positioning hole 8. The diameter of the second casing 6 is smaller than that of the first casing 4. Remove the object in the second casing 6, such as Figure 7 and Figure 8 As shown, the object in the second casing 6 includes the backfilled silicate cement dry mix slurry 5 mentioned above, and then the second casing 6 is removed to form a solidified hole 1. Since the diameter of the second casing 6 is smaller than that of the first casing, a solid hole wall 2 will be formed on the inner wall of the solidified hole;

[0054] Step 5: Repeat step 4 and complete all the solidified holes 1 in sequence according to the pile skipping construction method. Figure 9 As shown;

[0055] Step 6: Construction of support piles is then carried out at the locations of the solidified holes 1. Following the skip pile construction method, support piles are sequentially constructed at all the locations of the solidified holes. The support piles are constructed on the previously completed clearing and solidifying hole structure. Each solidified hole 1 is then drilled and filled with concrete to form the support piles.

[0056] The supporting piles include plain concrete supporting piles 10 and reinforced concrete supporting piles 9. Figure 10As shown, the plain concrete support piles 10 and the reinforced concrete support piles 9 are alternately arranged in sequence. The plain concrete support piles 10 are directly filled with concrete and do not contain steel bars.

[0057] The cement in the Portland cement dry mix slurry 5 of this embodiment is ordinary PC32.5 Portland cement, and the cement parameter is 8%, about 96kg / m3 (the slurry weight is 12KN / m3).

[0058] For the above-mentioned construction method, the following is a more specific implementation plan:

[0059] 1. Step 1 includes the following specific implementation plans:

[0060] (1) According to the staked-out pile position, the first casing 4 is placed. The first casing 4 is made of 12mm steel plate with an inner diameter of 1700mm. The soil around the center of the pile position and within 0.5m around the first casing is excavated, and the bottom of the pit is leveled. The center line of the casing coincides with the center line of the designed support pile position.

[0061] (2) Figure 2 As shown, the first casing 4 is buried at a depth of 1.5m and is 0.5m above the ground. The maximum allowable error in the plane is 50mm, and the vertical inclination is no more than 1%. The first casing was buried. The on-site inspection showed that the plane error of the casing was 10mm and the vertical inclination was 0.5%.

[0062] (3) Use a total station for precise positioning. The drilling rig should be positioned accurately, horizontally and stably. The allowable deviation between the center of the drilling rig turntable and the center of the first casing should not be greater than 20 mm. The construction elevation of the bored pile driver is the site level elevation (+6.00 m).

[0063] (4) Slurry preparation and drilling: Mainly for suspending drill cuttings, protecting the wall, and consolidating the wall. The surface elevation of the mud pool and sedimentation tank should be 0.5-1m lower than the first casing to facilitate smooth flow of the Portland cement dry-mix mud. Sediments in the sedimentation tank and mud pool should be regularly removed. Drilling should be carried out using the reverse circulation slag removal method; the mud liquid level in the hole should remain stable and should not be lower than 300mm below the construction ground.

[0064] (5) The clearance depth is 1m below the middle layer 102 of the weak sea-land interactive reclamation geology (exceeding 1m can determine whether the middle layer of the weak sea-land interactive reclamation geology has been passed).

[0065] (6) Hole solidification: PC32.5 ordinary Portland cement dry mix slurry with a cement content of 8%, approximately 96 kg / m3 (slurry weight is 12 kN / m3). Backfill material is used to solidify the holes. The solid hole structure exceeds the middle stratum by less than 1m. The subsequent concrete guide wall is constructed after the filled hole is stable.

[0066] 2. Production of concrete guide wall 3 in step 3

[0067] (1) Conduct survey according to the leveling points and the survey control network, lay out the center position of the pile, lay out the range line of the concrete guide wall 3, the center line of the control base pile and the starting pile position, set up the guide control line 2.5m away from the pile edge line, and draw the baseline to ensure that the pile position deviation is within 10mm. The pile top elevation is measured using a level. Figure 5 As shown, the positions of piles and concrete guide walls are laid out and made.

[0068] (2) The width of the concrete guide wall 3 is 5.5 meters and the thickness is 0.4 meters. The size of the positioning hole 8 on the concrete guide wall 3 is the diameter of the support pile plus 80 mm. The excavation or filling is leveled to an absolute elevation of 6 meters. The template reinforcement during the production of the concrete guide wall 3 is supported by φ48 steel pipes, with horizontal and transverse steel pipes pulled in opposite directions with a spacing of 0.8 meters. The steel bars of the concrete guide wall 3 are double-layer and bidirectional φ12@150 steel mesh. The concrete guide wall is cast with C20 concrete.

[0069] 3. Step 4 includes the following specific implementation plans:

[0070] (1) After the strength of the concrete guide wall 3 reaches 75%, reposition the stakeout line, determine the center of the pile, and place the point on the concrete guide wall as the drilling rig positioning control point. Move the casing drilling rig to the correct position, aligning the center of the casing station pipe holder with the center of the pile position, and control the verticality within 3‰.

[0071] (2) The second casing 6 is a double-walled steel casing with a thickness of 12 mm and a clearance diameter of 1.5 m. The steel casing is double-walled, and each section of the steel casing (2-6 m long) is connected by bolt joints. After the first section of the second casing is completely pressed into the soil (the second casing is 1.2 to 1.5 m higher than the guide wall surface for easy connection), the verticality is checked and the deviation is corrected and adjusted until the designed bottom mark of the hole is reached.

[0072] (3) After the drilling rig is in place, the first section of the second casing is hoisted into the jaws of the pile driver. After the verticality of the pile pipe is adjusted, the pile is pressed down to a depth of about 1.5 to 2.5 m. The depth of the super-deep excavation surface at the bottom of the second casing is always kept greater than 2.5 m.

[0073] (4) Strictly control the verticality of the first and second casings: The verticality of the second casing depends on the verticality at a depth of 5 to 6 meters at the beginning of the excavation. Select two mutually perpendicular directions on the ground and use a theodolite or a line cone to monitor the verticality of the second casing above the ground. If any deviation is found, correct it immediately. After each section of the second casing is pressed and before the next section is installed, use a "measuring ring" to check the verticality in the hole and correct the deviation. There are three methods for correction: using the drilling rig cylinder, B pile correction, and A pile correction.

[0074] (5) Use the grab bucket 7 to dig out the objects in the second casing, and use the grab bucket 7 to drop down and take the soil, such as Figure 7 shown.

[0075] When approaching the bottom of the hole, the grab bucket should be placed and grabbed gently to avoid disturbing the bottom soil layer. When the hole is completed, the outer pipe should be ahead by 0.5 to 1.5 meters. After the hole is completed, the hole diameter, depth and bottom condition should be checked with a detector, and the fallen soil and muddy water should be cleaned up and covered for protection.

[0076] (6) After the hole is completed, the bottom of the hole is inspected, loose soil is removed, and the hole depth and verticality are measured. The hole depth and verticality must meet the design requirements before proceeding to the next process.

[0077] The technical effects achieved by this embodiment are:

[0078] (1) The skipping pile clearing method removes obstacles such as artificial land reclamation gravel, pebble layers, small boulders, abandoned pile heads and construction waste; the pile holes need to be overlapped when using the skipping pile construction method to avoid hole collapse, pipe bursts, and pile hammers sliding into adjacent holes that have been completed, ensuring the verticality of the bite pile hole and the effect of the full-set pipe bite pile water-stop curtain.

[0079] (2) Use silicate cement dry-mixed mud for backfilling to ensure that the subsequent bite pile casing construction can smoothly pass through the middle layer of the soft sea-land interactive reclamation geology and drill holes to obtain soil.

[0080] (3) The bottom surface of the first casing should be no less than 2.5m from the excavation surface during excavation, which can prevent problems such as hole collapse and diameter shrinkage during pile construction;

[0081] (5) A concrete guide wall is set up, and positioning holes are set up on the concrete guide wall. When the first section of the casing is inserted into the positioning hole, the gap between the casing and the positioning hole can be kept uniform, which solves the problems of insufficient foundation bearing capacity, unstable foundation, and unbalanced equipment construction.

[0082] (6) The straightness of all casings configured with single-section casing and pile length is checked, the verticality of the drill pipe is controlled, and the verticality monitoring and inspection of the piles such as ground monitoring, in-hole inspection, and correction are applied during the drilling process to ensure the plane positioning and verticality of the interlocking piles.

[0083] The above embodiments of the present invention are not intended to limit the scope of protection of the present invention, and the implementation methods of the present invention are not limited thereto. All other modifications, replacements or changes made to the above structures of the present invention based on the above contents of the present invention, in accordance with common technical knowledge and customary means in this field, without departing from the above basic technical ideas of the present invention, should fall within the scope of protection of the present invention.

Claims

1. A method for constructing support piles using a soft land-sea alternating land reclamation geological support pile obstacle clearing and hole fixing structure, characterized in that: The soft land-sea interactive reclamation geological support pile obstacle clearing and fixing hole structure includes a plurality of solidified holes formed by a skipping pile construction method, wherein adjacent solidified holes partially overlap, and the solidified holes extend downward to the lower layer of the soft land-sea interactive reclamation geological surface. The positions of the solidified holes are aligned one by one with the positions of the support piles. A solidified hole wall is provided on the inner wall of the solidified hole, and the material of the solidified hole wall is silicate cement dry-mixed mud. The formation process of the solidified hole wall is limited and shaped by a casing. A concrete guide wall is laid on the upper plane of the soft land-sea interactive reclamation geological surface, and positioning holes are formed on the concrete guide wall corresponding to the positions of the solidified holes. The cement parameter in the silicate cement dry-mixed mud is 8%; The construction method comprises the following steps: Step 1: Pressing a first casing into the location of the solidified hole, excavating the object in the first casing, then backfilling the first casing with Portland cement dry mix slurry, and then removing the first casing, thereby completing the clearing and backfilling of a solidified hole; Step 2: Repeat step 1 and follow the pile skipping construction method to complete the clearing and backfilling of all the solidification holes in sequence. After that, all the solidification holes are filled with Portland cement dry mix mud; Step 3: laying the concrete guide wall on the upper plane of the soft land-sea interactive reclamation geology, and forming positioning holes on the concrete guide wall corresponding to the positions of the solidification holes; Step 4: At the location of the solidifying hole, a second casing is pressed in along the positioning hole, wherein the diameter of the second casing is smaller than that of the first casing. The object in the second casing is dug out, and then the second casing is removed to form the solidifying hole, and a solidifying hole wall is formed on the inner wall of the solidifying hole; Step 5: Repeat step 4 and complete all the solidification holes in sequence according to the pile skipping construction method; Step 6: construct support piles at the locations of the solidified holes, and complete the support piles at the locations of all the solidified holes in sequence according to the skipping pile construction method.

2. The construction method according to claim 1, characterized in that: In step 1, the center line of the first casing is aligned with the center line of the corresponding supporting pile, and the bottom surface of the hole formed by the object in the first casing is processed to be flat.

3. The construction method according to claim 1, wherein: In step 1, the bottom surface of the hole formed by excavating the first casing is more than 1 meter lower than the middle layer of the weak sea-land interactive reclamation geology.

4. The construction method according to claim 1, characterized in that: The supporting piles include plain concrete supporting piles and reinforced concrete supporting piles, and the plain concrete supporting piles and reinforced concrete supporting piles are alternately arranged in sequence.

5. The construction method according to claim 1, characterized in that: In step 1, the bottom surface of the first casing is not less than 2.5m away from the excavation surface during excavation.

6. The construction method according to claim 1, characterized in that: The bottom of the solidified hole is more than 1 meter lower than the middle layer of the weak sea-land interactive reclamation geology.

7. The construction method according to claim 1, characterized in that: The thickness of the concrete guide wall is 0.4 meters.

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