Caisson shipping wharf system, construction method and design method

Abstract

The invention relates to the technical field of wharf construction, in particular to a caisson shipping wharf system, a construction method and a design method. The caisson shipping wharf system comprises: a wharf platform, a coastline extending from a coastline on a coastal side; the upper ends of the foundation piles are fixedly embedded in the wharf platform, and the foundation piles are steel pipe piles; the steel sheet piles are arranged on the landside of the wharf platform, the lower portions of the steel sheet piles are fixedly embedded, and rock blocks are stacked on the sides, away from the wharf platform, of the upper portions of the steel sheet piles. The caisson shipping wharf system provided by the invention can be quickly constructed and formed and has relatively high bearing capacity, the steel pipe piles are adopted as main vertical supporting components of the wharf platform, relatively high bearing capacity can be realized at relatively low cost, and the bearing and shipping requirements of large structures such as caissons and the like are met; the steel sheet piles are arranged on the landside of the wharf platform, so that large transverse bearing capacity of the wharf platform can be achieved with low cost. The steel pipe piles and the steel sheet piles are convenient to dismantle, dismantling cost can be reduced, and therefore caisson shipping cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wharf construction, and in particular to a caisson shipping wharf system, a construction method and a design method. Background Art

[0002] The construction process of a gravity wharf usually includes the following steps: making caissons in a prefabrication yard; moving the caissons to the designed location on the coast; and constructing the caisson superstructure. Among them, the caissons are often moved to the designed location on the coast by work barges. The specific operations include: moving the caissons from the prefabrication yard to the shore shipping wharf, loading the caissons onto the work barges from the shipping wharf, and transporting and lowering the caissons by the work barges.

[0003] During the actual construction, the technical personnel found that in most construction plans, the shipping wharf is a temporary facility, which will be dismantled after the caisson is shipped. If it is built with cast-in-place piles according to the standards of permanent facilities, the shipping cost will be greatly increased, and the dismantling after shipping will be troublesome; if it is built with the standards of temporary facilities, the existing temporary wharf will be difficult to bear due to the huge weight of the caisson unit. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the background technology and provide a caisson shipping terminal system, construction method and design method, which has the advantages of low construction cost, large bearing capacity and convenient dismantling.

[0005] In a first aspect, the present invention provides a caisson shipping terminal system, comprising:

[0006] The wharf platform has a land side and a sea side which are arranged opposite to each other, and the sea side extends out from the coastline;

[0007] At least two foundation piles, the foundation piles support the dock platform, the upper ends of the foundation piles are embedded in the dock platform, and the foundation piles are steel pipe piles;

[0008] Steel sheet piles are arranged on the landward side of the wharf platform, the lower part of the steel sheet piles is embedded, and blocks of stone are piled on the upper part of the steel sheet piles away from the wharf platform.

[0009] The present invention provides a caisson shipping wharf system, which can be quickly constructed and has a large bearing capacity, and can be used for caisson shipping. Steel pipe piles are used as the main vertical supporting components of the wharf platform. The steel pipe piles have the characteristics of convenient installation, fast construction speed, and large bearing capacity. They can achieve a large bearing capacity at a relatively low cost and meet the bearing and shipping needs of large structures such as caissons. Steel sheet piles are arranged on the landward side of the wharf platform, and the steel sheet piles are embedded and fixed, and blocks of stone are piled on the other side, so that a large lateral bearing capacity of the wharf platform can be achieved at a relatively low cost. The steel pipe piles and steel sheet piles are easy to dismantle, which can reduce the dismantling cost and thus reduce the caisson shipping cost.

[0010] As a preferred embodiment of the present invention, it also includes a shipping channel connected to the dock platform, a transitional block stone layer is provided at the connection between the shipping channel and the dock platform, the surface layer of the shipping channel and the dock platform are both overlapped on the transitional block stone layer, and the transitional block stone layer is filled with blocks.

[0011] The transitional block stone layer is filled with blocks of stone, which have high hardness and small settlement. The transitional block stone layer can reduce the settlement of the connection between the dock platform and the shipping channel, so that large structures such as caissons can be smoothly transported to the dock platform.

[0012] As a preferred embodiment of the present invention, the surface layer of the shipping channel is inclined, and the dock platform is located at the lower end of the inclination; a crushed stone cushion layer is arranged between the dock platform and the transitional stone layer therebelow, and the crushed stone cushion layer is filled with crushed stones; the upper part of the steel sheet pile is embedded in the transitional stone layer.

[0013] As a preferred embodiment of the present invention, the foundation piles are arranged in rows along the offshore direction, and the foundation piles in a row closest to the seaward side are arranged densely.

[0014] The row of foundation piles closest to the sea side is densely packed, which can increase the vertical and lateral bearing capacity of the sea side of the wharf platform. By increasing the vertical bearing capacity, the wharf platform can meet the needs of semi-submersible barge overlap and facilitate the transportation of caissons by semi-submersible barges; by increasing the lateral bearing capacity, it can meet the needs of ship mooring and wharf platform collision prevention.

[0015] As a preferred solution of the present invention, a slope surface is provided below the dock platform, and a stone protection surface is provided on the surface of the slope surface; at least part of the foundation piles penetrate the stone protection surface.

[0016] As a preferred solution of the present invention, a semi-submersible barge overlapping platform is provided on the seaward side of the dock platform, and the upper surface of the semi-submersible barge overlapping platform is lower than the upper surface of the dock platform.

[0017] By setting up a semi-submersible barge overlapping platform, it is convenient to overlap and fix the semi-submersible barge, thereby facilitating the transportation of large structures such as caissons to the semi-submersible barge.

[0018] As a preferred embodiment of the present invention, a supporting steel plate is provided on the upper surface of the semi-submersible barge overlapping platform; a rubber pad is provided on the side wall of the dock platform facing the sea, and the rubber pad is located above the semi-submersible barge overlapping platform; the dock platform and the semi-submersible barge overlapping platform are arranged integrally.

[0019] As a preferred solution of the present invention, the dock platform is provided with a mooring post; the dock platform is thickened near the semi-submersible barge overlapping platform.

[0020] In a second aspect, the present invention provides a construction method for the caisson shipping terminal system as described above, comprising the following steps:

[0021] S1. Driving the foundation piles at the designed position, the foundation piles are steel pipe piles;

[0022] Excavating a transition groove, wherein the transition groove is located on the landward side of the designed position of the wharf platform;

[0023] Driving the steel sheet piles into the transition trough, and laying stone blocks on both sides of the steel sheet piles;

[0024] S2. The wharf platform is cast in situ, the top ends of the foundation piles are embedded in the bottom of the wharf platform, and the landward side of the wharf platform abuts against the steel sheet piles.

[0025] In a third aspect, the present invention provides a design method for the caisson shipping terminal system as described above, comprising the following steps:

[0026] A1. Determine the maximum bearing load of the dock platform based on the caisson;

[0027] A2. Develop the structure of the dock platform based on the maximum load-bearing capacity of the dock platform;

[0028] A3. Determine the deadweight of the dock platform based on the dock platform structure;

[0029] A4. Load combination based on the maximum bearing load of the wharf platform, the deadweight of the wharf platform, the lap load, the mooring force, the horizontal force of the caisson barge towing, and the earth pressure of the stone retaining wall of the caisson shipping channel on the wharf platform;

[0030] A5. Constructing a caisson shipping terminal system design model based on the terminal platform structure and load combination structure;

[0031] A6. Calculate whether the strength and stiffness of the steel pipe piles meet the design requirements based on the caisson shipping terminal system design model. If not, modify the terminal platform structure in step A2 and repeat steps A3-A6 until the strength and stiffness of the steel pipe piles meet the design requirements and obtain a terminal platform structure that meets the design requirements;

[0032] A7. Based on the wharf platform structure that meets the design requirements, calculate the shear bearing capacity of the wharf platform structure without stirrups or bent steel bars under local loads or concentrated reaction forces, and whether the overall stability of the slope meets the design requirements. If not, modify the wharf platform structure in step A2 and repeat steps A3-A6 until the strength and stiffness of the steel pipe piles meet the design requirements and a wharf platform structure that meets the design requirements is obtained.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a caisson shipping wharf system, which can be quickly constructed and has a large bearing capacity, and can be used for caisson shipping. Steel pipe piles are used as the main vertical supporting components of the wharf platform. The steel pipe piles have the characteristics of convenient installation, fast construction speed, and large bearing capacity. They can achieve a large bearing capacity at a relatively low cost and meet the bearing and shipping needs of large structures such as caissons. Steel sheet piles are arranged on the landward side of the wharf platform, and the steel sheet piles are embedded and fixed, and blocks of stone are piled on the other side, so that a large lateral bearing capacity of the wharf platform can be achieved at a relatively low cost. The steel pipe piles and steel sheet piles are easy to dismantle, which can reduce the dismantling cost and thus reduce the caisson shipping cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the caisson shipping terminal system of the present invention (side view);

[0036] Figure 2 for Figure 1 Enlarged view of part A in the middle;

[0037] Figure 3 for Figure 1 Enlarged view of middle part B;

[0038] Figure 4 It is a pile arrangement diagram of the caisson shipping terminal system of the present invention;

[0039] Figure 5 It is a structural schematic diagram of the caisson shipping terminal system of the present invention (top view);

[0040] Figure 6 Schematic diagram of airbag distribution;

[0041] Figure 7 This is a schematic diagram of airbag pressure calculation;

[0042] Figure 8 Schematic diagram of pile bottom reaction force when the caisson is located at the rear edge of the wharf platform 1;

[0043] Fig. 9 Schematic diagram of pile bottom reaction force when the caisson is located in the middle of the wharf platform 1;

[0044] Fig.10 Schematic diagram of pile bottom reaction force when the caisson is located at the front edge of the wharf platform 1;

[0045] Fig.11 This is the stress distribution diagram during the strength review of the steel pipe pile;

[0046] Fig.12 The results of slope stability analysis.

[0047] Markings in the figure:

[0048] 1- Dock platform;

[0049] 11-foundation piles; 12-steel sheet piles; 13-gravel cushion; 14-slope surface; 15-stone protection surface; 16-bollard; 17-landside; 18-seaside;

[0050] 2- Shipping channel;

[0051] 21-transitional block layer; 22-transitional trough;

[0052] 3- Semi-submersible barge docking platform;

[0053] 31-supporting steel plate; 32-rubber pad;

[0054] 4- Airbag. DETAILED DESCRIPTION

[0055] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0056] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0057] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0058] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0059] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0060] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0061] Example 1

[0062] See also Figures 1 to 5 The present embodiment provides a caisson shipping terminal system, including a terminal platform 1 and at least two foundation piles 11, the foundation piles 11 support the terminal platform 1, the upper ends of the foundation piles 11 are embedded in the terminal platform 1, and the foundation piles 11 are steel pipe piles; the landward side 17 of the terminal platform 1 is provided with steel sheet piles 12, the lower part of the steel sheet piles 12 is embedded, and blocks of stone are piled on the upper side of the steel sheet piles 12 away from the terminal platform 1.

[0063] The dock platform 1 is the upper structure of the shipping dock. One side of the dock platform 1 is connected to the caisson prefabrication yard, and the other side extends out of the coastline for a certain distance so that there is sufficient water depth below this side to meet the draft requirements of the working barge. The extended side can be defined as the seaward side 18; the caisson can be moved from the prefabrication yard to the dock platform 1 through air bags, and further moved on the dock platform 1 to the seaward side 18, and barged from the seaward side 18.

[0064] The foundation piles 11 are connected to the lower part of the wharf platform 1 and are used to support the wharf platform 1. The lower part of the foundation piles 11 is buried in the rock mass or soil mass. The deadweight and upper load of the wharf platform 1 can be transferred downward through the foundation piles 11. Figure 1 and Figure 5 As shown, a number of foundation piles 11 are arranged along the transverse and longitudinal directions of the dock platform 1, and some of the foundation piles 11 are located outside the coastline, and the upper parts of these foundation piles 11 are exposed to the sea water.

[0065] In order to meet the load-bearing requirements and facilitate later removal, the foundation piles 11 of this embodiment are steel pipe piles. Steel pipe piles have the advantages of fast construction speed, convenient underwater construction, and convenient later removal, and the overall construction cost is relatively low. In terms of load-bearing capacity, the bearing capacity of steel pipe piles is closer to the cast-in-place piles used in permanent docks, and is suitable for temporary shipping docks.

[0066] In order to meet the stability requirements when the caisson is shipped, the upper ends of the foundation piles 11 of this embodiment are embedded in the dock platform 1, and steel sheet piles 12 are provided on the land side 17 of the dock platform 1 opposite to the sea side 18, and blocks of stone are piled on the side of the steel sheet piles 12 away from the dock platform 1. The upper side of the steel sheet piles 12 abuts against the dock platform 1, and the lower part is embedded in the soil or rock. Through the squeezing of the steel sheet piles 12 and the blocks of stone, a large lateral force can be applied to the dock platform 1, thereby greatly improving the lateral bearing capacity of the shipping dock.

[0067] Therefore, the caisson shipping wharf system provided in the present embodiment can be quickly constructed and has a large bearing capacity, which can be used for caisson shipping. Steel pipe piles are used as the main vertical supporting components of the wharf platform 1. The steel pipe piles have the characteristics of convenient installation, fast construction speed and large bearing capacity. They can achieve a large bearing capacity at a relatively low cost and meet the bearing and shipping needs of large structures such as caissons. Steel sheet piles 12 are arranged on the landward side 17 of the wharf platform 1. The steel sheet piles 12 are embedded and have stones piled on the other side. The larger lateral bearing capacity of the wharf platform 1 can be achieved at a relatively low cost. The steel pipe piles and steel sheet piles 12 are easy to dismantle, which can reduce the dismantling cost and thus reduce the caisson shipping cost.

[0068] In some embodiments, the caisson shipping terminal system also includes a shipping channel 2, which connects the caisson prefabrication yard and the terminal platform 1. A transition block stone layer 21 is arranged below the intersection of the terminal platform 1 and the shipping channel 2. The surface layer of the shipping channel 2 and the terminal platform 1 are overlapped on the transition block stone layer 21, and the transition block stone layer 21 is filled with blocks.

[0069] The block stone has high hardness and small settlement. By setting a transition block stone layer 21 at the intersection, the settlement of the connection between the dock platform 1 and the shipping channel 2 can be reduced, which is beneficial to reducing the height difference between the surface of the dock platform 1 and the surface of the shipping channel 2 during the passage of the caisson, so that the caisson can move more smoothly from the shipping channel 2 to the dock platform 1.

[0070] Preferably, the upper portion of the steel sheet pile 12 is embedded in the transitional stone layer 21 , and the transitional stone layer 21 can reduce the deformation of the steel sheet pile 12 , thereby improving the lateral rigidity and stability of the wharf platform 1 .

[0071] Preferably, the surface layer of the shipping channel 2 is inclined, and the dock platform 1 is located at the lower end of the inclination; the inclined setting facilitates the movement of the caisson, and the inclination slope can be selected from 1:55 to 1:65, and is further preferably 1:60.

[0072] A crushed stone cushion layer 13 is further arranged between the wharf platform 1 and the transitional block stone layer 21 therebelow, and the crushed stone cushion layer 13 is filled with crushed stones.

[0073] In some embodiments, the foundation piles 11 are arranged in rows along the offshore direction, and the row of foundation piles 11 closest to the seaward side 18 is densely arranged.

[0074] The row of foundation piles 11 closest to the seaward side 18 is densely arranged. The densely arranged arrangement can improve the vertical and lateral bearing capacity of the seaward side 18 of the dock platform 1. By improving the vertical bearing capacity, the dock platform 1 can meet the needs of semi-submersible barge overlap, which is convenient for transporting caissons by semi-submersible barges; by improving the lateral bearing capacity, the needs of ship mooring and dock platform 1 anti-collision can be met.

[0075] Taking this embodiment as an example, five rows of foundation piles 11 are arranged in the offshore direction, the row closest to the seaward side 18 is provided with 8 foundation piles 11 , and the remaining four rows are provided with 4 foundation piles 11 each.

[0076] In some embodiments, a slope surface 14 is provided below the dock platform 1 , and a stone protection surface 15 is provided on the surface of the slope surface 14 ; at least part of the foundation piles 11 penetrate the stone protection surface 15 .

[0077] In some embodiments, a semi-submersible barge overlapping platform 3 is provided on the seaward side 18 , and the upper surface of the semi-submersible barge overlapping platform 3 is lower than the upper surface of the dock platform 1 .

[0078] By providing the semi-submersible barge overlapping platform 3, it is convenient to overlap and fix the semi-submersible barge, thereby facilitating the transportation of large structures such as caissons to the semi-submersible barge.

[0079] Preferably, the wharf platform 1 and the semi-submersible barge overlapping platform 3 are integrally arranged, a supporting steel plate 31 is provided on the upper surface of the semi-submersible barge overlapping platform 3, and a rubber pad 32 is provided on the side wall of the seaward side 18 of the wharf platform 1, and the rubber pad 32 is located above the semi-submersible barge overlapping platform 3.

[0080] Preferably, the dock platform 1 is provided with a mooring post 16 ; the dock platform 1 is thickened at a position close to the semi-submersible barge overlapping platform 3 .

[0081] Example 2

[0082] This embodiment provides a construction method for the caisson shipping terminal system as described in Embodiment 1, comprising the following steps:

[0083] S1. Drive the foundation pile 11 into the designed position, and the foundation pile 11 is a steel pipe pile;

[0084] Excavating a transition groove 22, the transition groove 22 is located at the landward side 17 of the designed position of the wharf platform 1, and two side slopes of the transition groove 22 are set;

[0085] The steel sheet piles 12 are driven into the transition groove 22, and blocks are laid on both sides of the steel sheet piles 12;

[0086] S2. Cast-in-place dock platform 1 , the top of foundation pile 11 is embedded in the bottom of dock platform 1 , and the landward side 17 of dock platform 1 abuts against steel sheet pile 12 .

[0087] Example 3

[0088] This embodiment provides a design method for a caisson shipping terminal system as claimed in any one of claims 1 to 8, characterized in that it comprises the following steps:

[0089] A1. Determine the maximum load-bearing capacity of the dock platform 1 according to the caisson;

[0090] A2. Develop the structure of the dock platform 1 based on the maximum load-bearing capacity of the dock platform 1;

[0091] A3. Determine the deadweight of the dock platform 1 based on the structure of the dock platform 1;

[0092] A4. Load combination based on the maximum bearing load of the wharf platform 1, the deadweight of the wharf platform 1, the lap load, the mooring force, the horizontal force of the caisson barge towing, and the earth pressure of the caisson shipping channel block stone retaining wall on the wharf platform;

[0093] A5. Constructing a caisson shipping terminal system design model based on the terminal platform 1 structure and the load combination structure;

[0094] A6. Calculate whether the strength and stiffness of the steel pipe piles meet the design requirements based on the caisson shipping terminal system design model. If not, modify the terminal platform 1 structure in step A2, and repeat steps A3-A6 until the strength and stiffness of the steel pipe piles meet the design requirements, and obtain a terminal platform 1 structure that meets the design requirements;

[0095] A7. Based on the wharf platform 1 structure that meets the design requirements, calculate the shear bearing capacity of the slab of the wharf platform 1 structure without stirrups or bent steel bars under local loads or concentrated reaction forces, and whether the overall stability of the slope meets the design requirements. If not, modify the wharf platform 1 structure in step A2, and repeat steps A3-A6 until the strength and stiffness of the steel pipe piles meet the design requirements, and obtain the wharf platform 1 structure that meets the design requirements.

[0096] The design method of the caisson shipping terminal system described in this embodiment proposes the structure of the terminal platform 1 based on the maximum bearing load of the terminal platform 1, and then uses the load combination component caisson shipping terminal system design model. The design model can systematically guide the design of the terminal platform 1 and the steel pipe piles, and can reasonably determine the structure of the terminal platform 1 and the steel pipe piles to meet the bearing requirements, and provide a theoretical basis for reducing the construction cost.

[0097] Take a caisson shipping project as an example:

[0098] The maximum load-bearing capacity of the wharf platform 1 is the load when the caisson is completely located on the wharf platform 1. For example, a caisson with a length (in the longitudinal direction) of 18.75 m has a weight of Qmax = 27770 kN. It is transported by 9 air bags 4 with a length of 16.75 m (effective length). Figure 6 As shown, the airbag 4 is arranged perpendicular to the longitudinal axis of the caisson, and the working height of the airbag 4 is 350 mm. At this time, the width of the pressure-bearing surface of a single airbag 4 is 1.021 m. When the airbag 4 is converted during transportation, the force applied to 9 airbags 4 is considered.

[0099] During the longitudinal movement of the caisson on the barge, the deadweight of the caisson acts entirely on the airbag 4. The effective length of a single airbag 4 is 16.75m, and the width of the pressure-bearing surface is 1.021m. Considering the forces of 9 airbags 4, the pressure of the bottom of the airbag 4 on the dock platform 1 is: 27770÷(16.75×1.021×9)=180.42kPa.

[0100] The design scheme of the transport channel 2 is as follows: a 5 cm gravel cushion layer 13 is laid on the bottom, a 20 t roller is used to compact the foundation and the gravel cushion layer 13, and a 20 cm thick C25 plain concrete layer is poured on the top; the shear bearing capacity of its inclined section can be determined by the following formula:

[0101]

[0102] Where:

[0103] V u - Design value of shear bearing capacity (N);

[0104] γ d -Structural coefficient, take 1.1;

[0105] β h - Section height influence coefficient;

[0106] f t -Design value of concrete axial tensile strength (N / mm^2);

[0107] b – width of rectangular section;

[0108] h0 - effective height of the section.

[0109] After calculation, the design value of the shear bearing capacity per unit width of the 200mm thick C25 plain concrete surface layer is Vu=228.6kN>180.42×1=180.42kN, and the shear bearing capacity meets the requirements.

[0110] The characteristic value of foundation bearing capacity after foundation treatment is ≥150kPa. The foundation bearing capacity verification is carried out according to the above standards. Please refer to Figure 7 :

[0111] The stress diffusion angle of the concrete and crushed stone cushion is 45°, and the pressure of the foundation below the cushion is:

[0112] P=180.42×1.021÷1.478+25×0.2+18×0.05=130.53kPa<150kPa, the foundation bearing capacity meets the requirements.

[0113] According to the local geological and hydrological conditions, the size and weight of the caisson on site are comprehensively considered to select the appropriate dock platform 1 structure type, so as to save investment as much as possible while ensuring the structural requirements. Under the action of the shipping load, verify whether the overall stability of the shipping dock and the bearing capacity of the foundation piles 11 meet the requirements for caisson shipping.

[0114] There are two schemes for this project; Scheme 1: 24m long and 27m wide along the coastline, with a high pile pier structure and a pier thickness of 1.5m. Five rows of φ1200mm (δ=18mm) steel pipe piles are set along the width direction, and the bearing layer at the pile end is strongly weathered granite. Slope excavation is adopted under the wharf, with an excavation slope of 1:3. A row of JU600*210*18 steel plate protection piles are set behind the wharf. The bottom of the piles penetrates the silty clay interlayer, and 2.5-3.5t blocks are used as retaining walls.

[0115] Plan 2: The shipping terminal plan 2 is 24m long and 27m wide along the coastline. It is a high pile pier structure with a thickness of 1.5m. Five rows of φ1200mm cast-in-place piles are set along the width direction, and the bearing layer at the pile end is strongly weathered granite; the lower part of the terminal is excavated in a sloped manner with an excavation slope of 1:3. A row of JU600*210*18 steel plate protection piles are set behind the terminal. The bottom of the piles penetrates the silty clay interlayer, and the steel sheet piles are backfilled with blocks of stone as a retaining wall.

[0116] The advantages of Plan 1 are: 1. Fast construction speed; 2. Easy to dismantle; 3. Lower project cost than Plan 2; Disadvantages: 1. Steel pipe piles have low rigidity and the overall deformation of the wharf is greater than that of Plan 2.

[0117] The advantages of Plan 2 are: 1. The durability of the wharf is better; 2. The overall rigidity of the wharf structure is greater and the deformation is smaller; the disadvantages are: 1. The construction speed of cast-in-place piles is slow; 2. Dismantling is difficult; 3. The project cost is higher than Plan 1.

[0118] After comprehensive comparative analysis, Plan 1 is recommended as the wharf structure plan.

[0119] The wharf structure calculation mainly includes the wharf platform structure calculation and the slope stability verification. The main calculation results of the recommended solution are as follows:

[0120] Midascivil was used to perform structural calculations for the wharf platform 1.

[0121] (1) Pier thickness 1.5m, material C35;

[0122] (2) Foundation pile 11 is a φ1200 steel pipe pile with a wall thickness of 18 mm, and is calculated based on the upper hinge and lower consolidation;

[0123] (3) Calculate using the m method

[0124] The soil spring of pile 11 is calculated according to the m method given in the foundation code: K = ab1mz.

[0125] Where: a—thickness of each soil layer;

[0126] b1—the calculated width of the pile;

[0127] m—proportional coefficient of foundation soil;

[0128] z—the distance between the midpoint of each soil layer and the ground.

[0129] The calculation width of the pile can be calculated as follows: When d ≥ 1.0m, b1 = k × k f ×(d+1)When d, b1=k×k f ×(1.5*d+0.5);

[0130] For single-row piles or multiple-row piles with L1 ≥ 0.6h1, k = 1.0;

[0131] For multiple rows of piles with L1<0.6h1, k=b2+(1-b2) / 0.6×L1 / h1;

[0132] Where b1 is the calculated width of the pile (m), b1≤2d;

[0133] d—pile diameter or the width of the pile perpendicular to the direction of horizontal external force (m);

[0134] k f —Pile shape conversion factor, depending on the horizontal force action surface (perpendicular to the horizontal force action direction), circular or circular end surface k f =0.9; rectangular section k f =1.0; for the combined section of round end and rectangle k f =(1-0.1*a / d);

[0135] k—inter-pile interaction coefficient parallel to the direction of horizontal force;

[0136] L1—clear distance between piles parallel to the direction of horizontal force action; when piles are arranged in a plum blossom shape, if the center distance c between two adjacent rows of piles is less than (d+1) m, it can be calculated based on the projection distance between the piles on the horizontal force action surface;

[0137] h1—Calculated buried depth of piles below the ground or local scour line, which can be taken as h1=3×(d+1), but shall not be greater than the buried depth h of piles below the ground or local scour line;

[0138] b2—A coefficient related to the number n of piles in a row parallel to the direction of action of the horizontal force. When n=1, b2=1.0; when n=2, b2=0.6; when n=3, b2=0.5; when n=4, b2=0.45.

[0139] Design loads include:

[0140] Deadweight: The deadweight of the wharf platform 1 includes the weight of internal steel bars and concrete;

[0141] Caisson pressure: The wharf platform is a rigid platform. The maximum weight of the shipped caisson is 2777t. The caisson size is 18.75m×16.75m×19m. The equivalent pressure of the caisson's deadweight on the wharf platform is:

[0142] p=2777×10÷18.75÷16.75=88.42kPa, the design pressure is 90kPa;

[0143] Lap load: 1200t; (1200t / 24m=500kN / m);

[0144] Mooring force: According to the requirements of the project department, two 350kN bollards are arranged at the front edge of the wharf platform 1;

[0145] Horizontal force of caisson barge-up: During the caisson barge-up process, when the caisson is located above the shipping wharf, under the traction of the winch, the rolling friction force of the airbag (the rolling friction coefficient of the airbag is taken as the empirical value of 0.05) is: 2777t×0.05=1388.5kN;

[0146] The soil pressure of two stones in the caisson unloading channel on the dock platform 1; the soil pressure is determined according to the density and height of the soil layer on site.

[0147] Combine loads: The ultimate limit state of load capacity is calculated based on the permanent combination of the effects of the permanent condition.

[0148] Load combinations:

[0149] ① Deadweight × 1.2 + average load × 1.4 + lap load × 1.2 + horizontal force of ship × 1.0 + 1.35 earth pressure;

[0150] ② Self-weight × 1.2 + average load × 1.4 + mooring force × 1.4 + lap load × 1.2 + horizontal force of caisson barge-on × 1.4.

[0151] Establish a finite element model and obtain the pile bottom reaction force of this project through the finite element model. Figure 8 , Fig. 9 , Fig.10 As shown, where: Figure 8 This is a schematic diagram of the pile bottom reaction force when the caisson is located at the rear edge of the wharf platform 1. Fig. 9 This is a schematic diagram of the pile bottom reaction force when the caisson is located in the middle of the wharf platform 1. Fig.10 It is a schematic diagram of the pile bottom reaction force when the caisson is located at the front edge of the wharf platform 1; it can be seen from the figure that the maximum value of the pile bottom reaction force is 3857.5kN.

[0152] The design value of the vertical ultimate bearing capacity of a single steel pipe pile is as follows:

[0153]

[0154] Table 1 Design value of vertical ultimate bearing capacity of single steel pipe pile

[0155] The bearing layer of the steel pipe pile is strongly weathered granite. The vertical ultimate bearing capacity of a single pile can reach 4183.52kN>3857.5kN. The design bearing capacity of pile 11 can meet the requirements.

[0156] Strength review of steel pipe piles, finite element analysis Fig.11 As shown, calculation shows that φ1200mm steel pipe piles (wall thickness 18mm) can meet the use requirements.

[0157] The buckling stability of the steel pipe piles was reviewed. As can be seen from the table below, the slenderness ratio and stability of the steel pipe piles meet the requirements.

[0158]

[0159] Table 2 Slenderness ratio review table of steel pipe piles

[0160] According to the review formula: The stability check table of steel pipe piles (Q345 steel) is as follows:

[0161]

[0162] Table 3 Steel pipe pile stability review table

[0163] It can be seen that the stability of steel pipe piles meets the requirements.

[0164] Carry out punching shear calculation for the wharf platform: Under the action of local load or concentrated reaction force, the punching shear bearing capacity of the plate without stirrups or bent steel bars shall meet the following requirements:

[0165] F1≤(0.7β h f t +0.25σ pc,m )ημ m h0

[0166] The coefficient η in the formula should be the smaller value of the following formula:

[0167]

[0168] Where:

[0169] β h —Cross-section height influence coefficient: when h is not greater than 800 mm, it is taken as 1; when h is not less than 2000 mm, it is taken as 0.9; in between, it is taken by linear interpolation;

[0170] f t —Design value of concrete axial tensile strength;

[0171] σ pc,m —The weighted average length of the effective precompression stress of concrete in two directions on the perimeter of the calculated section should be controlled within 1.0N / ㎡~3.5N / ㎡;

[0172] μ m —Calculate the perimeter of the section, taking the most unfavorable perimeter of the vertical section of the plate at a distance h0 / 2 from the perimeter of the local load or concentrated reaction surface;

[0173] h0—effective height of the section;

[0174] β s—When the area of ​​action of local load or concentrated load reaction force is rectangular, the ratio of the long side to the short side should not be greater than 4; when it is less than 2, take 2; for circular punching surface, take 2;

[0175] α s —Column position influence coefficient: the center column is 40; the side column is 30; the corner column is 20.

[0176] After calculation, the shear bearing capacity of the wharf platform is 9415kN>3857.5kN, and the shear bearing capacity meets the requirements.

[0177] Check the stability of the entire slope:

[0178] The average load of the slope stability is calculated according to the standard value of 90kpa, and the Ordinary analysis method of the "GeoStudioSlope" software is used to calculate the overall stability of the shipping terminal.

[0179] See also Fig.12 , Fig.12 The results of slope stability analysis.

[0180] Caissons shall not be stored on both sides of the shipping channel and shall be treated as empty. Correction of the partial coefficient of soil slope stability resistance may be considered.

[0181] The modified partial coefficient of soil slope stability resistance considering the side friction is: Ls = 45.39m; Lt = 24m; A = 667.4m2; The modified partial coefficient of resistance is: γ' R =0.991×(1+667.4 / (2×24×45.3))=1.29>1; Taking the correction into consideration, the slope stability can meet the specification requirements, and it is required that caissons shall not be stored on both sides of the shipping channel and shall be treated as empty.

[0182] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A caisson shipping terminal system, characterized in that: include: The wharf platform (1) has a land side (17) and a sea side (18) arranged opposite to each other, wherein the sea side (18) extends out from the coastline; at least two foundation piles (11), the foundation piles (11) supporting the dock platform (1), the upper ends of the foundation piles (11) being embedded in the dock platform (1), and the foundation piles (11) being steel pipe piles; The steel sheet piles (12) are arranged on the landward side (17) of the wharf platform (1), the lower part of the steel sheet piles (12) is embedded, and the upper part of the steel sheet piles (12) is piled with stones on the side away from the wharf platform (1).

2. The caisson shipping terminal system according to claim 1, characterized in that: It also comprises a shipping channel (2) connected to the wharf platform (1), a transitional block stone layer (21) is provided at the connection between the shipping channel (2) and the wharf platform (1), the surface layer of the shipping channel (2) and the wharf platform (1) are both overlapped on the transitional block stone layer (21), and the transitional block stone layer (21) is filled with blocks of stone.

3. The caisson shipping terminal system according to claim 2, characterized in that: The surface layer of the shipping channel (2) is arranged to be inclined, and the dock platform (1) is located at the lower end of the inclination; A crushed stone cushion layer (13) is provided between the wharf platform (1) and the transitional stone layer (21) therebelow, and the crushed stone cushion layer (13) is filled with crushed stones; The upper part of the steel sheet pile (12) is embedded in the transitional block stone layer (21).

4. The caisson shipping terminal system according to claim 1, characterized in that: The foundation piles (11) are arranged in rows along the offshore direction, and the row of foundation piles (11) closest to the seaward side (18) is densely arranged.

5. The caisson shipping terminal system according to claim 1, characterized in that: A slope surface (14) is provided below the dock platform (1), and a stone protection surface (15) is provided on the surface of the slope surface (14); at least part of the foundation piles (11) are penetrated by the stone protection surface (15).

6. The caisson shipping terminal system according to claim 1, characterized in that: A semi-submersible barge overlapping platform (3) is provided on the seaward side (18) of the dock platform (1), and the upper surface of the semi-submersible barge overlapping platform (3) is lower than the upper surface of the dock platform (1).

7. The caisson shipping terminal system according to claim 6, characterized in that: The upper surface of the semi-submersible barge overlapping platform (3) is provided with a supporting steel plate (31); The side wall of the seaward side (18) of the dock platform (1) is provided with a rubber pad (32), and the rubber pad (32) is located above the semi-submersible barge overlapping platform (3); The wharf platform (1) and the semi-submersible barge overlapping platform (3) are arranged integrally.

8. The caisson shipping terminal system according to claim 6, characterized in that: The dock platform (1) is provided with a mooring post (16); the dock platform (1) is thickened at a position close to the semi-submersible barge overlapping platform (3).

9. A construction method for a caisson shipping terminal system as claimed in any one of claims 1 to 8, characterized in that: The steps include: S1. driving the foundation pile (11) into the designed position, wherein the foundation pile (11) is a steel pipe pile; Excavating a transition groove (22), wherein the transition groove (22) is located on the landward side (17) of the designed position of the dock platform (1); Driving the steel sheet piles (12) into the transition groove (22), and laying stone blocks on both sides of the steel sheet piles (12); S2. The wharf platform (1) is cast in situ, the top end of the foundation pile (11) is embedded in the bottom of the wharf platform (1), and the landward side (17) of the wharf platform (1) abuts against the steel sheet pile (12).

10. A design method for a caisson shipping terminal system as claimed in any one of claims 1 to 8, characterized in that: The steps include: A1. Determine the maximum load-bearing capacity of the pier platform (1) according to the caisson; A2. The structure of the dock platform (1) is formulated based on the maximum load-bearing capacity of the dock platform (1); A3. Determine the deadweight of the dock platform (1) based on the structure of the dock platform (1); A4. Combining loads based on the maximum bearing load of the wharf platform (1), the deadweight of the wharf platform (1), the lap load, the mooring force, the horizontal force of the caisson barge towing, and the earth pressure of the stone retaining wall of the caisson shipping channel on the wharf platform; A5. A caisson shipping terminal system design model is constructed based on the terminal platform (1) structure and the load combination structure; A6. Calculate whether the strength and stiffness of the steel pipe piles meet the design requirements based on the caisson shipping terminal system design model. If not, modify the terminal platform (1) structure in step A2, and repeat steps A3-A6 until the strength and stiffness of the steel pipe piles meet the design requirements, and obtain a terminal platform (1) structure that meets the design requirements; A7. Based on the wharf platform (1) structure that meets the design requirements, calculate the shear bearing capacity of the slab of the wharf platform (1) structure without stirrups or bent steel bars under local loads or concentrated reaction forces, and whether the overall stability of the slope meets the design requirements. If not, modify the wharf platform (1) structure in step A2, and repeat steps A3-A6 until the strength and stiffness of the steel pipe piles meet the design requirements, and obtain a wharf platform (1) structure that meets the design requirements.

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