Offshore sand dam construction protection measure physical model test method and device

Abstract

The invention discloses an offshore sand dam construction protection measure physical model test method and device. The method comprises the steps that marine hydrological information of an engineering area and parameter information of a sand dam are obtained; designing a model scale according to the parameter information; according to the parameter information of the sand dam, a sand adding device is designed and calibrated, and an antifouling curtain model is designed; based on marine hydrological information, constructing a seabed model and calibrating dynamic conditions of a physical model test; and arranging a sand adding device and an anti-fouling curtain, operating power conditions, and obtaining topographic data of the sand dam model. According to the technical scheme provided by the invention, the parameter information of the to-be-added sand dam and the corresponding required sand adding device and antifouling curtain are calculated by obtaining the marine hydrological information of the engineering area, the sand dam model meeting the similarity criterion is constructed, and the sand loss rate in the sand dam construction process is simulated through the physical model test, so that the sand dam construction efficiency is improved. The defects that the construction precision is low and the cost of manpower and material resources is additionally increased due to the fact that the silt loss rate is high in the actual sand dam hydraulic reclamation process can be overcome.

Description

Technical Field

[0001] The invention relates to a physical model test method and device for offshore sand dam construction protection measures, belonging to the technical field of offshore engineering. Background Art

[0002] Offshore artificial sand dams simulate natural underwater sand dams on sandy coasts. On the one hand, they can break waves in advance to reduce the energy acting on the beach. On the other hand, the sand dam sediments are transported to the shore under the action of waves, playing the role of nearshore sand replenishment. They are marine ecological restoration engineering measures based on "natural solutions". In the actual construction process, since artificial offshore sand dams are generally located in shallow waters near the coast, they face problems such as high construction difficulty, short construction period, and lack of construction technology; at the same time, due to the influence of uninterrupted tides and waves, artificial offshore sand dams have difficulties such as high loss rate and difficult to control molding accuracy.

[0003] Sand filling is the main construction method for offshore sand dams at present, which relies on special filling ships and auxiliary equipment to blow sand into the target area to form sand dams. However, it is extremely difficult to fill sand dams with sand dams that meet the design requirements under tidal and wave conditions. The challenges faced during the construction process include not only how to accurately control the deposition location and accumulation form of the sand, but also how to solve the problem of sand loss caused by water flow and waves during the filling construction process. Due to the late start of domestic marine ecological restoration, the relevant research results on artificial sand dams are not rich enough, which makes it difficult to support the scientific construction of offshore sand dams in the ocean.

[0004] At present, although numerical simulation is widely used in the study of sediment transport and seabed evolution in marine environments, it cannot accurately simulate the complex sand blowing process and multi-component sediment transport process. The traditional method of building temporary cofferdams to protect sand dams will greatly increase the time and economic costs of construction. Therefore, it is urgent to propose an effective protection and simulation technology method for the offshore sand dam construction process to ensure the effect of offshore sand dam construction and reduce construction costs. Summary of the invention

[0005] Therefore, the object of the present invention is to provide a physical model test method and device for offshore sand dam construction protection measures, so as to ensure the effect of offshore sand dam construction and reduce construction costs.

[0006] In order to achieve the above-mentioned object, the present invention provides a physical model test method for offshore sand dam construction protection measures, comprising:

[0007] Obtain oceanographic information and sand bar parameter information of the project area;

[0008] Designing a model scale according to the ocean hydrological information and parameter information of the sand bar;

[0009] According to the parameter information of the sand dam, the sand adding device is designed and calibrated, and the anti-fouling curtain model is designed;

[0010] Based on the ocean hydrological information, construct a seabed model and calibrate the dynamic conditions of the physical model test;

[0011] The sand adding device and anti-fouling curtain are arranged, the power conditions are operated, and the topographic data of the sand dam model is obtained.

[0012] Furthermore, the ocean hydrological information includes wave, water level, tidal current and seabed topography information in the sand dam construction area;

[0013] The parameter information of the sand dam includes location information, size information, and sand filling particle size.

[0014] Furthermore, according to the ocean hydrological information and the parameter information of the sand bar, the model scale is designed, which specifically includes:

[0015] Determine the physical model test parameters of the required sand dam construction area according to the ocean hydrological information;

[0016] Determine the model scale through the physical model test parameters according to the test site conditions, test equipment, instrument performance and test requirements;

[0017] Determining test configuration parameters of the sand dam model according to the model scale;

[0018] According to the test configuration parameters, parameter information of the sand dam in the sand dam model is determined.

[0019] Furthermore, the sand adding device is designed and rated according to the parameter information of the sand dam, specifically including:

[0020] Add frequency converter and flow meter to water pipe;

[0021] Add a control valve to the sand bucket above the sink;

[0022] The amount of sand discharged is adjusted by the control valve according to the amount of water discharged from the water pipe.

[0023] Furthermore, based on the ocean hydrological information, a seabed model is constructed, which specifically includes:

[0024] The seabed model is set in the water tank according to the model scale and drawings.

[0025] Furthermore, the obtaining of the terrain data of the sand dam model specifically includes:

[0026] Arranging the sand-adding device and the anti-fouling curtain on the seabed model;

[0027] Run the wave machine and flow pump to generate the calibrated power conditions for the prefabrication time;

[0028] activating the Gaza device;

[0029] The formed sand dam model is scanned to generate point cloud data.

[0030] In a second aspect, the present invention further provides a physical model test device for protective measures during offshore sand dam construction, which is applied to the physical model test method for protective measures during offshore sand dam construction provided in the first aspect, comprising:

[0031] A parameter information determination module is used to obtain the ocean hydrological information and sand dam parameter information of the project area;

[0032] A scale setting module, used for designing a model scale according to the ocean hydrological information and parameter information of the sand bar;

[0033] A parameter information processing module is used to design and calibrate a sand adding device and design an anti-fouling curtain model according to the parameter information of the sand dam;

[0034] A model setting module, used to construct a seabed model and calibrate the dynamic conditions of the physical model test based on the ocean hydrological information;

[0035] The terrain data acquisition module is used to arrange the sand adding device and the anti-fouling curtain, operate the power conditions, and acquire the terrain data of the sand dam model.

[0036] Furthermore, the sand-adding device comprises:

[0037] Support plate;

[0038] A sand bucket is fixed to the top of the support plate, and an extension pipe at the bottom of the sand bucket is equipped with a control valve and passes through the support plate;

[0039] A water pipe, equipped with a flow meter, one end of which is connected to the extension pipe;

[0040] A water pump is connected to the other end of the water pipe, and the water pump is electrically connected to a frequency converter.

[0041] Furthermore, the anti-fouling curtain comprises:

[0042] At least two buoyancy rods are arranged in parallel in the sand dam model and perpendicular to the water flow direction;

[0043] Cables, along the direction of water flow, are respectively connected to the terminals of the buoyancy rods;

[0044] An anchor chain, one end of which is connected to the terminal of the buoyancy rod, and the other end of which is fixed to the bottom of the sand dam model through an anchor block;

[0045] A geotextile is used to wrap the buoyancy rod and the anchor chain.

[0046] By adopting the above technical scheme, the ocean hydrological information of the project area is obtained, and the parameter information of the sand dam model to be added and the corresponding required sand adding device and anti-fouling curtain are calculated, so as to construct a sand dam model that meets the similarity criteria, and then obtain the terrain data of the corresponding sand dam model, which can prevent the low construction accuracy and additional manpower and material costs caused by the high sediment loss rate during the actual sand dam filling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a physical model test method for offshore sand dam construction protection measures provided by the present invention;

[0048] Figure 2 A flow chart of designing a model scale in a physical model test method for offshore sand dam construction protection measures provided by the present invention;

[0049] Figure 3 A flow chart of designing and calibrating a sand adding device in a physical model test method for offshore sand dam construction protection measures provided by the present invention;

[0050] Figure 4 A flow chart of obtaining topographic data of a sand dam model in a physical model test method for offshore sand dam construction protection measures provided by the present invention;

[0051] Figure 5 A structural principle diagram of a physical model test device for offshore sand dam construction process and protective measures provided by the present invention;

[0052] Figure 6 A schematic diagram of the structure of a sand adding device in a physical model test device for an offshore sand dam construction process and protective measures provided by the present invention;

[0053] Figure 7 A schematic diagram of a control valve belonging to a physical model test device for an offshore sand dam construction process and protective measures provided by the present invention;

[0054] Figure 8 A schematic diagram of the structure of an anti-fouling curtain in a physical model test device for an offshore sand dam construction process and protective measures provided by the present invention;

[0055] Fig. 9 A schematic diagram of the structure of a sand dam model in a physical model test device for an offshore sand dam construction process and protective measures provided by the present invention;

[0056] Fig.10 A distribution diagram of filling points and measuring points in a physical model test device for an offshore sand dam construction process and protective measures provided by the present invention;

[0057] Fig.11 An elevation diagram of a sand dam with anti-fouling curtain in a physical model test device for an offshore sand dam construction process and protective measures provided by the present invention;

[0058] Fig.12 The invention provides an elevation diagram of a sand dam without an anti-fouling curtain in a physical model test device for an offshore sand dam construction process and protective measures.

[0059] In the figure: 1. Support plate; 2. Sand bucket; 3. Extension pipe; 4. Control valve; 5. Water pipe; 6. Flow meter; 7. Water pump; 8. Frequency converter; 9. Buoyancy rod; 10. Cable; 11. Anchor chain; 12. Anchor block; 13. Geotextile. DETAILED DESCRIPTION

[0060] The present invention is further described in detail below through the accompanying drawings and specific implementation methods. At present, the construction method of offshore sand dams mainly adopts the sand dam filling construction method, and there are the following technical problems: 1. Low precision; 2. Increased manpower and time costs in the construction process; 3. Additional increase in the construction cost of the sand dam, so there is a need for a physical model test method for offshore sand dam construction protection measures that ensures the effect of offshore sand dam construction and reduces construction costs.

[0061] Embodiment 1

[0062] like Figures 1 to 4 As shown, the present invention provides a physical model test method for offshore sand dam construction protection measures, comprising:

[0063] S10: Obtaining the ocean hydrological information of the project area and the parameter information of the sand dam, wherein the ocean hydrological information includes the wave, water level, tide and seabed topography information of the sand dam construction area; determining the parameter information of the required sand dam model; the parameter information of the sand dam includes the location information, size information and sand filling particle size.

[0064] S20: designing a model scale according to the ocean hydrological information and the parameter information of the sand bar; the corresponding specific steps include:

[0065] S21: Determine the physical model test parameters required for the sand dam construction area based on the marine hydrological information; the way to obtain the marine hydrological information includes but is not limited to using the wave numerical model to infer the design wave elements and design water level at the location of the beach restoration project based on the long-term measured wave, tide and wind data of the ocean station near the project area; for example, the acquired marine hydrological information includes the following: water depth of 4m, effective wave height of 1m, effective period of 4s, and flow rate of 0.5m / s as wave elements in the sand dam filling test.

[0066] S22: The model scale is determined through the physical model test parameters according to the test site conditions, test equipment, instrument performance and test requirements; here it is necessary to consider the effective size of the water tank to be placed, the performance of the wave maker, the wave energy coverage area, the test terrain, the main hydrodynamic driving factors, etc. The horizontal scale of this test is set to 1:8, the vertical scale is set to 1:8, and the model is a normal model.

[0067] S23: According to the model scale, determine the test configuration parameters of the sand dam model; in the process of determining the test configuration parameters, it is necessary to meet the gravity similarity criterion to correctly simulate the wave movement, and it is also necessary to meet the similarity of sediment initiation, sediment settlement, beach profile deformation and coastal sand transport to more accurately simulate the beach scouring and silting changes. According to the sediment initiation conditions:

[0068]

[0069] T min =8πKd 2 / v

[0070]

[0071] Among them, g is the acceleration due to gravity 9.81ms -2 , v is the viscosity coefficient of water 1.36×10 -6 m 2 s -1 The median particle size of engineering fill sand is 0.5 mm. After multiple experiments, natural sand with a median particle size of 0.19 mm was used as model sand.

[0072] S24: Determine the parameter information of the sand dam in the sand dam model according to the test configuration parameters. When the sand dam in the selected project area has a top width of 25m, a bottom width of 55m, a height of 1.5m, and a slope of 1:10; considering the model scale, the parameter information of the sand dam in the sand dam model can be a top width of 2.5m, a bottom width of 5m, a height of 0.25m, and a slope of 1:5.

[0073] S30: Designing and calibrating a sand adding device and an anti-fouling curtain model according to the parameter information of the sand dam; specifically including:

[0074] S31: Add a frequency converter and a flow meter to the water pipe; the frequency converter and the flow meter are used to accurately adjust the water flow to ensure that the flow scale requirements in the test are met.

[0075] S32: Add a control valve to the sand bucket above the water tank; the water tank is used to simulate the sea conditions in the working area. The sand bucket can be adjusted according to the parameters of the water tank, and the sand and mud dry materials fall by gravity and mix with the water flow. This design ensures the flexibility and adjustability of the operation and can meet the diverse test needs.

[0076] S33: According to the water output in the water pipe, the sand output is adjusted through the control valve. It should be noted that before the adjustment, the water flow rate and the sand flow rate need to be calculated respectively. For example, when the sand required for the on-site sand filling dam is about 0.85m 3 In the actual filling process, the minimum flow rate of water and sand is about 2500m 3 / h, where the ratio of water to sand is about 4:1. According to the 1:8 ratio, the flow rate of the sand-water mixture is 13.8m 3 / h, the water flow rate is 11.05m 3 / h, the flow rate of sand is 2.75m 3 / h.

[0077] In addition, it should be added that the anti-fouling curtain is constructed by using buoyancy bars and geotextiles, and using cables, anchor chains and anchor blocks as the fixing structure. The buoyancy bars and anchor chains are wrapped and fixed with geotextiles, and the buoyancy bars are ensured to be above the water surface and the anchor chains are at the bottom of the water. The anchor blocks are connected to the buoyancy bars and anchor chains with cables, and it is ensured that the anchor blocks will not move. The DYLY-108S tension sensor is arranged on the cable, with a measurement range of 0-50kN and an accuracy level of up to 0.5. It is used to measure the force on each cable.

[0078] S40: Based on the ocean hydrological information, construct a seabed model and calibrate the dynamic conditions of the physical model test; in addition, the process of constructing the seabed model specifically includes: setting the seabed model in the water tank according to the model scale and drawings.

[0079] S50: arranging the sand adding device and the anti-fouling curtain, operating the power condition, and obtaining the topographic data of the sand dam model; specifically including:

[0080] S51: Arranging the sand adding device and the anti-fouling curtain on the seabed model;

[0081] S52: operating the wave machine and the flow pump to generate the calibrated power conditions for a preset time; specifically, adding water to the aforementioned water tank to a predetermined water level, and during this operation, the flow and wave making equipment needs to be operated to meet the aforementioned power conditions.

[0082] For the wave maker to generate waves in the water tank, according to the test conditions, the test wave elements and spectrum shape meet the test accuracy requirements, that is, the irregular wave spectrum adopts the JONSWAP spectrum improved by Goda:

[0083]

[0084] Among them, H 1 / 3 is the effective wave height, T pis the peak period, f p is the spectrum peak frequency, and the spectrum peak enhancement factor γ is 3.3.

[0085] S53: Activate the sand adding device and use the anti-fouling curtain to reduce the loss of sand during the deposition process. When the sand adding device stops working, stop the aforementioned flow and wave making equipment. Multiple sand adding devices can be configured, and multiple filling points can be set in the project area.

[0086] S54: Scanning the formed sand dam model to form point cloud data. In an optional implementation, a three-dimensional laser scanner may be used to measure observation points set on both sides of the formed sand dam model, thereby obtaining point cloud data of the sand dam model.

[0087] In order to ensure the accuracy of the sand dam model, multiple groups of steps S10-S50 may be performed repeatedly.

[0088] The present invention provides a physical model test method for offshore sand dam construction protection measures, which obtains the ocean hydrological information of the project area, designs the corresponding required sand adding device and anti-fouling curtain according to the parameter information of the sand dam model to be added, and constructs a sand dam model with the same conditions as the actual project area, and then obtains the terrain data of the corresponding sand dam model through physical model testing, which provides a reference for the actual construction plan, thereby selecting a construction plan with lower sediment loss rate and higher precision during the actual sand dam filling process.

[0089] Embodiment 2

[0090] Based on the first embodiment, the present invention proposes a physical model test device for offshore sand dam construction process and protective measures, such as Figures 5 to 12 As shown, including:

[0091] Parameter information determination module 01, used to obtain the ocean hydrological information and sand dam parameter information of the project area;

[0092] The scale setting module 02 is used to design the model scale according to the ocean hydrological information and the parameter information of the sand bar;

[0093] The parameter information processing module 03 is used to design and calibrate the sand adding device and design the anti-fouling curtain model according to the parameter information of the sand dam; wherein the sand adding device includes:

[0094] Support plate 1;

[0095] A sand bucket 2 is fixed to the top of the support plate 1, and an extension pipe 3 at the bottom of the sand bucket 2 is equipped with a control valve 4 and passes through the support plate 1;

[0096] A water pipe 5 is provided with a flow meter 6, and one end of the water pipe 5 is connected to the extension pipe 3;

[0097] A water pump (submersible pump) 7 is connected to the other end of the water pipe 5, and the water pump 7 is electrically connected to a frequency converter 8. The water pump 7 in the device is equipped with a frequency converter 8 and a flow meter 6, which can accurately adjust the water flow rate according to demand to ensure that the flow rate scaling requirements in the test are met. When adding sand, the sand bucket 2 is placed on the support plate 1 above the water tank, and the dry sand and mud falls by gravity and mixes with the water flow. The amount and proportion of the above-mentioned mud and water need to be calculated in advance. For example, the sand required for on-site sand filling is about 0.85m 3 In the actual filling process, the minimum flow rate of water and sand is about 2500m 3 / h, where the ratio of water to sand is about 4:1. According to the 1:8 ratio, the flow rate of the sand-water mixture is 13.8m 3 / h, the water flow rate is 11.05m 3 / h, the flow rate of sand is 2.75m 3 / h.

[0098] The anti-fouling curtain comprises: at least two buoyancy rods 9, arranged in parallel in the sand dam model and perpendicular to the water flow direction;

[0099] The cables 10 are connected to the ends of the buoyancy rods 9 respectively along the water flow direction;

[0100] An anchor chain 11, one end of which is connected to the terminal end of the buoyancy rod 9, and the other end is fixed to the bottom of the sand dam model through an anchor block 12;

[0101] The geotextile 13 wraps the buoyancy rod 9 and the anchor chain 11. The geotextile 13 is a national standard filament of 500g, with good water permeability and will not hinder the passage of water. The buoyancy rod 9 and the anchor chain 11 are wrapped and fixed with the geotextile 13 to ensure that the buoyancy rod 99 is above the water surface and the anchor chain 11 is at the bottom of the water; the anchor block 12, the buoyancy rod 9 and the anchor chain 11 are connected with a cable 10 to fix the anchor block 12. A DYLY-108S tension sensor is arranged on the anchor block 12 cable 10, with a measurement range of 0-50kN and an accuracy level of up to 0.5.

[0102] Model setting module 04, used to construct a seabed model and calibrate the dynamic conditions of the physical model test based on the ocean hydrological information;

[0103] The terrain data acquisition module is used to arrange the sand adding device and the anti-fouling curtain, operate the power conditions, and obtain the terrain data of the sand dam model. The anti-fouling curtain and the sand adding device of the sand dam model are set on one side. For example, if the width of the water tank is 1.5m, the anti-fouling curtain and the sand adding device are set on the 0.9m wide side, and the water pump is set on the 0.6m wide side. The middle is separated by a partition to ensure that the submersible pumping and the sand dam filling do not interfere with each other during the test.

[0104] By establishing the sand dam model, it is found that when there is no anti-fouling curtain protection, the sand loss in the sand dam filling is 20.42%, and after the anti-fouling curtain protection, the sand loss in the sand dam filling is 2.60%. The sediment loss is reduced by 17.82%. The stress of the anti-fouling curtain cable is analyzed, and it is found that the stress of the wave-facing cable is greater than that of the cables in other positions, and the maximum stress is 8.44KN.

[0105] An offshore sand dam design device provided in an embodiment of the present invention adopts the technical means of the physical model test method of offshore sand dam construction protection measures to achieve the same technical effect, which will not be repeated here.

Claims

1. A physical model test method for offshore sand dam construction protection measures, characterized in that: include: Obtain oceanographic information and sand bar parameter information of the project area; Designing a model scale according to the ocean hydrological information and parameter information of the sand bar; According to the parameter information of the sand dam, the sand adding device is designed and calibrated, and the anti-fouling curtain model is designed; Based on the ocean hydrological information, construct a seabed model and calibrate the dynamic conditions of the physical model test; The sand adding device and anti-fouling curtain are arranged, the power conditions are operated, and the topographic data of the sand dam model is obtained.

2. The physical model test method for offshore sand dam construction protection measures according to claim 1, characterized in that: The ocean hydrological information includes wave, water level, tidal current and seabed topography information in the sand dam construction area; The parameter information of the sand dam includes location information, size information, and sand filling particle size.

3. The physical model test method for offshore sand dam construction protection measures according to claim 2, characterized in that: According to the ocean hydrological information and the parameter information of the sand bar, the model scale is designed, which specifically includes: Determine the physical model test parameters of the required sand dam construction area according to the ocean hydrological information; Determine the model scale through the physical model test parameters according to the test site conditions, test equipment, instrument performance and test requirements; Determining test configuration parameters of the sand dam model according to the model scale; According to the test configuration parameters, parameter information of the sand dam in the sand dam model is determined.

4. The physical model test method for offshore sand dam construction protection measures according to claim 3, characterized in that: The sand adding device is designed and rated according to the parameter information of the sand dam, specifically including: Add frequency converter and flow meter to water pipe; Add a control valve to the sand bucket above the sink; The amount of sand discharged is adjusted by the control valve according to the amount of water discharged from the water pipe.

5. The physical model test method for offshore sand dam construction protection measures according to claim 4, characterized in that: Based on the ocean hydrological information, constructing a seabed model specifically includes: The seabed model is set in the water tank according to the model scale and drawings.

6. The physical model test method for offshore sand dam construction protection measures according to claim 5, characterized in that: The step of obtaining the terrain data of the sand dam model specifically includes: Arranging the sand-adding device and the anti-fouling curtain on the seabed model; Run the wave machine and current pump to generate the calibrated power conditions for the prefabrication time; activating the Gaza device; The formed sand dam model is scanned to generate point cloud data.

7. A physical model test device for protective measures during offshore sand dam construction, applied to the physical model test method for protective measures during offshore sand dam construction as claimed in any one of claims 1 to 6, characterized in that: include: A parameter information determination module is used to obtain the ocean hydrological information and sand dam parameter information of the project area; A scale setting module, used for designing a model scale according to the ocean hydrological information and parameter information of the sand bar; A parameter information processing module is used to design and calibrate a sand adding device and design an anti-fouling curtain model according to the parameter information of the sand dam; A model setting module, used to construct a seabed model and calibrate the dynamic conditions of the physical model test based on the ocean hydrological information; The terrain data acquisition module is used to arrange the sand adding device and the anti-fouling curtain, operate the power conditions, and acquire the terrain data of the sand dam model.

8. The physical model test device for protective measures during offshore sand dam construction according to claim 7 is characterized in that: The Gaza device comprises: Support plate; A sand bucket is fixed to the top of the support plate, and an extension pipe at the bottom of the sand bucket is equipped with a control valve and passes through the support plate; A water pipe, equipped with a flow meter, one end of which is connected to the extension pipe; A water pump is connected to the other end of the water pipe, and the water pump is electrically connected to a frequency converter.

9. The physical model test device for protective measures during offshore sand dam construction process according to claim 7 is characterized in that: The anti-fouling curtain comprises: At least two buoyancy rods are arranged in parallel in the sand dam model and perpendicular to the water flow direction; Cables, along the direction of water flow, are respectively connected to the terminals of the buoyancy rods; An anchor chain, one end of which is connected to the terminal of the buoyancy rod, and the other end of which is fixed to the bottom of the sand dam model through an anchor block; A geotextile is used to wrap the buoyancy rod and the anchor chain.

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