A model and experimental method considering the construction process of estuary spur dike

Abstract

The present invention belongs to the technical field of estuary engineering, and specifically discloses a model and its test method for considering the construction process of estuary spur dikes, the model includes a water trough and a water flow regulating control end; gates are provided at the front and rear ends of the water trough, and a bottom slope is provided at the bottom end; a lower groove is provided in the middle of the water trough, a plurality of cylindrical support frames are embedded in the lower groove, and a spur dike model is provided on the top of the cylindrical support frame; a topographic instrument is provided on the top of the lower groove, and a propeller current meter and a water level sensor are provided on the front side of the lower groove in the water trough; the propeller current meter, the water level sensor, the gate, and the bottom slope are electrically connected to the water flow regulating control end respectively. The present invention adopts the above-mentioned model and its test method for considering the construction process of estuary spur dikes, the model and its test method can fully consider the dynamic changes in the construction process, and evaluate the scouring and silting of the riverbed during the construction of the spur dike under the complex hydrodynamic conditions of the reciprocating flow in the estuary, so as to provide certain technical support for the design and construction of temporary spur dike projects.

Description

Technical Field

[0001] The invention belongs to the technical field of estuary engineering, and in particular relates to a model considering the construction process of an estuary spur dike and a test method thereof. Background Art

[0002] In the dry construction of cofferdams used in seawall reinforcement projects, temporary spur dikes perpendicular to the shore are usually built first, and then longitudinal cofferdam construction is carried out. On the one hand, it can slow down the scouring of the cofferdam body by water flow and ensure the safety of the cofferdam; on the other hand, the spur dike can promote siltation in the area behind the dam, raise the riverbed to save the cost of cofferdam construction, and can also serve as a dam for the longitudinal cofferdam to speed up construction efficiency. The cofferdam will be dismantled after the reinforcement project is completed.

[0003] Currently available technologies are mostly targeted at long-term service spur dike projects. For temporary spur dike projects, the service life of the spur dike is relatively short, and there is little research on the time scale effect of the spur dike construction process on the surrounding water flow and riverbed sediment. Currently, there is no model test method that can consider the construction process of estuary spur dikes.

[0004] Therefore, there is a need to develop a model and test method for the estuary spur dike construction process that takes into account the model, which can effectively solve the problem that the existing spur dike engineering model test method cannot characterize the defects of the dynamic construction process of the spur dike. Summary of the invention

[0005] The purpose of the present invention is to provide a model and a test method for the construction process of an estuary spur dike. The model and the test method can fully consider the dynamic changes in the construction process, evaluate the scouring and silting of the riverbed during the construction of the spur dike under the complex hydrodynamic conditions of the reciprocating flow in the estuary, and provide certain technical support for the design and construction of temporary spur dike projects.

[0006] To achieve the above-mentioned purpose, the present invention provides a model that takes into account the construction process of an estuary spur dike, comprising a water trough and a water flow regulating control end; gates are provided at the front and rear ends of the water trough, and a bottom slope is provided at the bottom end, and the gates and the bottom slope are movably connected to the water trough; a lower groove is provided in the middle of the water trough, and a plurality of cylindrical support frames are pre-embedded in the lower groove, and a spur dike model is provided on the top of the cylindrical support frame; a topometer is provided on the top of the lower groove, and the two ends of the topometer are respectively connected to the left and right ends of the water trough; a propeller flowmeter and a water level sensor are provided on the front side of the lower groove in the water trough; the propeller flowmeter, the water level sensor, the gate and the bottom slope are respectively electrically connected to the water flow regulating control end.

[0007] Preferably, model sand made of resin material is provided in the lower groove.

[0008] Preferably, the spur dike model is of open design and is made of acrylic.

[0009] An experimental method for a model considering the construction process of an estuarine spur dike comprises the following steps:

[0010] Step S1, determining the water flow conditions of the test conditions according to the estuary hydrological data of the study area;

[0011] Step S2, making a spur dam model according to the spur dam design data;

[0012] Step S3, laying out the terrain of the test site and debugging the water flow;

[0013] Step S4, conducting a spur dike construction process test;

[0014] Step S5: The topograph measures the terrain and performs data processing.

[0015] Preferably, step S1 specifically comprises:

[0016] Step S11, collecting hydrological data of the study area, selecting representative water flow conditions during the spur dike construction period, and converting them into model scale;

[0017] Step S12: Select a number of consecutive tidal cycles to simulate the water flow conditions of the spur dike from construction to completion.

[0018] Preferably, step S2 specifically includes collecting spur dike construction design data, and making a plurality of spur dike models of different lengths and sizes based on actual spur dike construction conditions.

[0019] Preferably, step S3 specifically comprises:

[0020] Step S31, excavating a lower groove matching the size of the water tank in the middle of the water tank;

[0021] Step S32, laying model sand made of resin material in the lower groove, and at the same time pre-buried in the lower groove a plurality of cylindrical support frames with a height consistent with the model sand, and installing a spur dam model on the upper end of the cylindrical support frame;

[0022] When pre-buried cylindrical support frames, avoid arranging them at the dam head position of spur dam models of various lengths;

[0023] Step S33, installing a propeller flow meter and a water level sensor on the front side of the lower groove in the water tank; installing a topographic meter above the spur dike model;

[0024] Step S34, importing the water level and flow rate data under the model test water flow condition into the water flow regulation control terminal;

[0025] Step S35, respectively control the gate openings at the front and rear ends of the water tank and the bottom slope of the water tank through the water flow regulation control end, adjust the indicated flow rate of the propeller flow meter and the water level sensor in the water tank, so that the water tank reaches the set flow rate and water level value.

[0026] Preferably, step S4 is specifically to divide the continuous process of spur dike construction into a plurality of fixed-length spur dike models according to the test water flow conditions; and replace the length of the spur dike model after each tidal cycle in units of tidal cycles to achieve the change of the spur dike from short to long.

[0027] Preferably, in step S4, spur dike models of different lengths are sequentially replaced on the cylindrical support frame after each tidal cycle to simulate the dynamic process of spur dike construction; the contact area between each cylindrical support frame and the spur dike model is ≤0.003m².

[0028] Preferably, step S5 specifically comprises:

[0029] Step S51, before measuring the terrain with a topograph, a number of terrain measuring points are arranged, and the number of terrain measuring points is adjusted according to the length change of the spur dike model;

[0030] Step S52, the topographic instrument collects data by dotting. When in use, the total measurement length, starting point position, measurement interval, number of measurement points, dotting speed and section parameters are first set; according to the set parameters, the topographic instrument automatically calculates the appropriate motor torque, enters the semi-automatic operation mode, and starts to collect topographic data;

[0031] a. Before the experiment begins, use a topograph to perform initial topographic measurements;

[0032] b. After the experiment begins, according to the set water flow conditions, before replacing the spur dikes of different sizes every other cycle, use a topographic instrument to record the topographic changes at each stage;

[0033] Step S53: After the test is completed, the collected terrain data is processed.

[0034] The present invention adopts the above-mentioned model and test method considering the construction process of estuary spur dike, and the beneficial effects are as follows:

[0035] (1) The model and test method of the present invention can reflect the changes in the scouring and silting of the surrounding riverbed during the dynamic construction of the spur dike, which is more in line with the actual engineering construction conditions;

[0036] (2) In order to prevent the spur dike from becoming unstable due to water flow impact during the test, the present invention adopts an open spur dike model, which is convenient for adding weight directly into the spur dike during the test, and effectively prevents the test failure caused by the instability of the spur dike by increasing the deadweight;

[0037] (3) The test method of the present invention is easy to operate and feasible.

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the overall structure of a model considering the construction process of a spur dike at an estuary and an embodiment of a test method thereof of the present invention;

[0040] Figure 2 It is a structural schematic diagram of a spur dike model of an embodiment of a model and a test method thereof considering the construction process of a spur dike at an estuary according to the present invention;

[0041] Figure 3 The present invention is a structural schematic diagram of a cylindrical support frame layout of a model and a test method embodiment of the present invention considering the construction process of a estuary spur dike; wherein (a) is a spur dike model with a length of 14 cm installed on a cylindrical support frame; (b) is a spur dike model with a length of 49 cm installed on a cylindrical support frame;

[0042] Figure 4 The present invention provides a model taking into account the construction process of an estuary spur dike and a measurement point arrangement diagram of an embodiment of a test method thereof.

[0043] Reference numerals

[0044] 1. Water tank; 2. Water flow regulation control end; 3. Gate; 4. Lower groove; 5. Cylindrical support frame; 6. Spur dike model; 7. Topographic instrument; 8. Propeller flow meter; 9. Water level sensor; 10. Bottom slope. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0046] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0047] like Figure 1 As shown, a model considering the construction process of a spur dike at an estuary includes a water tank 1 and a water flow regulating control end 2. Gates 3 are provided at the front and rear ends of the water tank 1, and a bottom slope 10 is provided at the bottom end thereof. The gates 3 and the bottom slope 10 are movably connected to the water tank 1. By adjusting the opening of the gates 3 and the slope of the bottom slope 10 of the water tank 1, the set flow rate and water level value can be achieved in the water tank 1.

[0048] A lower groove 4 is provided in the middle of the water tank 1, and model sand made of resin material is provided in the lower groove 4. The model sand is selected with a sediment particle size gradation that meets the test requirements and is used to simulate the scouring and silting changes of the riverbed around the spur dike.

[0049] like Figure 2-Figure 3As shown, several cylindrical support frames 5 are embedded in the lower groove 4, and a spur dike model 6 is provided on the top of the cylindrical support frame 5. Considering that the failure of the experiment caused by the instability of the spur dike can be effectively prevented by increasing the deadweight during the experiment, the spur dike model 6 is designed to be open and made of acrylic. A topographic meter 7 is provided on the top of the lower groove 4, and the two ends of the topographic meter 7 are respectively connected to the left and right ends of the water tank 1. A propeller flowmeter 8 and a water level sensor 9 are provided on the front side of the lower groove 4 in the water tank 1. The propeller flowmeter 8, the water level sensor 9, the gate 3, and the bottom slope 10 are all electrically connected to the water flow regulation control end 2.

[0050] Example

[0051] An experimental method for a model considering the construction process of an estuarine spur dike comprises the following steps:

[0052] Step S1, determining the water flow conditions of the test conditions according to the estuary hydrological data of the study area.

[0053] Step S11: collect hydrological data of the study area, select representative water flow conditions during the spur dike construction period, and convert them into model scale.

[0054] Step S12: Select a number of consecutive tidal cycles to simulate the water flow conditions of the spur dike from construction to completion.

[0055] In this embodiment, a low tide period is selected as a representative, wherein the maximum flow velocity at high tide is 11 cm / s, and the maximum flow velocity at low tide is 7 cm / s.

[0056] Step S2: making a spur dam model 6 according to the spur dam design data.

[0057] The design data of spur dam construction were collected, and based on the actual spur dam construction situation, acrylic open trapezoidal spur dam models 6 with five sizes of 14 cm, 28 cm, 35 cm, 42 cm, and 49 cm were made to simulate the dynamic stage of spur dam construction.

[0058] Step S3: laying the terrain of the test site and adjusting the water flow.

[0059] Step S31, a lower groove 4 with a length of 3m, a width of 1.25m and a height of 30cm is excavated in the middle of a water tank 1 with a length of 60m, a width of 4m and a height of 1.2m as a moving bed test section.

[0060] Step S32, laying model sand made of resin material in the lower groove 4 to simulate the topographical features and scouring and silting of the actual riverbed. At the same time, four cylindrical support frames 5 with the same height as the model sand are pre-buried in the lower groove 4, and the spur dike model 6 is installed on the upper end of the cylindrical support frame 5. The cylindrical support frame 5 can be used to easily replace the spur dike model 6 of different lengths and sizes during the dynamic construction of the simulated spur dike, and the changes in the construction progress of the spur dike can be reflected.

[0061] When pre-buried cylindrical support frame 5 is arranged, avoid arranging it at the dam head position of spur dike models 6 of various lengths, so as to avoid the influence on the riverbed scouring process at the spur dike dam head during the test.

[0062] Step S33 , installing a propeller flow meter 8 and a water level sensor 9 on the front side of the lower groove 4 in the water tank 1 , and installing a topographic meter 7 above the spur dike model 6 .

[0063] Step S34, importing the water level and flow rate data under the model test water flow conditions into the water flow regulation control terminal 2.

[0064] Step S35, the water flow regulating control terminal 2 controls the opening of the gate 3 at the front and rear ends of the water tank 1 and the bottom slope 10 of the water tank 1, and adjusts the indicated flow rate of the propeller flow meter 8 and the water level sensor 9 in the water tank 1, so that the water tank 1 reaches the set flow rate and water level value. After the water flow conditions are adjusted, the experiment can be officially started.

[0065] Step S4, conducting a spur dike construction process test.

[0066] According to the test water flow conditions, the continuous process of spur dike construction is divided into several steps of fixed-length spur dike models 6. Taking the tidal cycle as a unit, the length of the spur dike model 6 is replaced every tidal cycle to achieve the change of the spur dike from short to long.

[0067] After each tidal cycle, the spur dike models 6 of different lengths and sizes are replaced in sequence on the cylindrical support frame 5 to simulate the dynamic process of spur dike construction. The contact area between each cylindrical support frame 5 and the spur dike model 6 is ≤ 0.003m², minimizing the potential impact of the contact area on the scouring result.

[0068] The model in this embodiment imitates the idea of ​​cascade constant flow widely used in engineering. According to the test water flow conditions, the continuous process of spur dike construction is divided into several fixed lengths of cascade. By replacing the length of the spur dike model 6 at regular intervals, the change of the spur dike from short to long is achieved, which can simulate the dynamic process of spur dike construction.

[0069] Step S5: The topographer 7 measures the terrain and performs data processing.

[0070] Step S51: The measurement points of this embodiment are arranged as follows: Figure 4 As shown, considering that the width of the drill bit of the topograph 7 is about 1.2 cm, in order to avoid the interference of the drill bit width of the topograph 7 on data collection while ensuring the density and accuracy of data collection, a measuring point is set every 3 cm, and 12-20 measuring points are set in the horizontal direction. 8-28 measuring points are set in each section in the vertical direction.

[0071] Step S52, the topographic instrument 7 collects data by dotting. When in use, the total measurement length, starting point position, measurement interval, number of measurement points, dotting speed and section parameters are set. According to the set parameters, the topographic instrument 7 automatically calculates the appropriate motor torque, enters the semi-automatic operation mode, and starts to collect topographic data.

[0072] a. Before the experiment begins, an initial topographic measurement is performed using a topographer 7.

[0073] b. After the experiment begins, according to the set water flow conditions, before replacing the spur dikes of different sizes every other cycle, a topographic instrument 7 is used to record the topographic changes at each stage.

[0074] Step S53: After the test is completed, the collected terrain data is processed.

[0075] Therefore, the present invention adopts the above-mentioned model and test method considering the construction process of estuary spur dikes. The model and test method can fully consider the dynamic changes in the construction process, and evaluate the scouring and silting of the riverbed during the construction of the spur dike under the complex hydrodynamic conditions of reciprocating flow in the estuary, thereby providing certain technical support for the design and construction of temporary spur dike projects.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A test method for a model considering the construction process of an estuary spur dike, characterized in that: The model includes a water trough and a water flow regulating control end; gates are provided at the front and rear ends of the water trough, and a bottom slope is provided at the bottom end, and the gates and the bottom slope are movably connected to the water trough; a lower groove is provided in the middle of the water trough, and a plurality of cylindrical support frames are embedded in the lower groove, and a spur dike model is provided on the top of the cylindrical support frame; a topographic instrument is provided on the top of the lower groove, and the two ends of the topographic instrument are respectively connected to the left and right ends of the water trough; a propeller flow meter and a water level sensor are provided on the front side of the lower groove in the water trough; the propeller flow meter, the water level sensor, the gate and the bottom slope are respectively electrically connected to the water flow regulating control end; The experimental method of the model includes the following steps: Step S1, determining the water flow conditions of the test conditions according to the estuary hydrological data of the study area; Step S11, collecting hydrological data of the study area, selecting representative water flow conditions during the spur dike construction period, and converting them into model scale; Step S12, selecting a number of consecutive tidal cycles to simulate the water flow conditions of the spur dike from construction to completion; Step S2, making a spur dam model according to the spur dam design data; Collect the design data of spur dike construction, and make several spur dike models of different lengths and sizes based on the actual spur dike construction situation; Step S3, laying out the terrain of the test site and debugging the water flow; Step S4, conducting a spur dike construction process test; The continuous process of spur dike construction is divided into several cascade fixed-length spur dike models according to the test water flow conditions. The length of the spur dike model is replaced after each tidal cycle, so that the spur dike changes from short to long. After each tidal cycle, spur dike models of different lengths and sizes are replaced in sequence on the cylindrical support frame to simulate the dynamic process of spur dike construction; the contact area between each cylindrical support frame and the spur dike model is ≤0.003m²; Step S5: The topograph measures the terrain and performs data processing.

2. A test method for a model considering the construction process of an estuary spur dike according to claim 1, characterized in that: Model sand made of resin material is arranged in the lower groove.

3. A test method for a model considering the construction process of an estuary spur dike according to claim 1, characterized in that: The spur dike model is of open design and is made of acrylic.

4. A test method for a model considering the construction process of an estuary spur dike according to claim 1, characterized in that: Step S3 specifically comprises: Step S31, excavating a lower groove matching the size of the water tank in the middle of the water tank; Step S32, laying model sand made of resin material in the lower groove, and at the same time pre-buried in the lower groove a plurality of cylindrical support frames with a height consistent with the model sand, and installing a spur dam model on the upper end of the cylindrical support frame; When pre-buried cylindrical support frames, avoid arranging them at the dam head position of spur dam models of various lengths; Step S33, installing a propeller flow meter and a water level sensor on the front side of the lower groove in the water tank; installing a topographic meter above the spur dike model; Step S34, importing the water level and flow rate data under the model test water flow condition into the water flow regulation control terminal; Step S35, respectively control the gate openings at the front and rear ends of the water tank and the bottom slope of the water tank through the water flow regulation control end, adjust the indicated flow rate of the propeller flow meter and the water level sensor in the water tank, so that the water tank reaches the set flow rate and water level value.

5. The test method of a model considering the construction process of an estuary spur dike according to claim 1, characterized in that: Step S5 specifically includes: Step S51, before measuring the terrain with a topograph, a number of terrain measuring points are arranged, and the number of terrain measuring points is adjusted according to the length change of the spur dike model; Step S52, the topographic instrument collects data by dotting. When in use, the total measurement length, starting point position, measurement interval, number of measurement points, dotting speed and section parameters are first set; according to the set parameters, the topographic instrument automatically calculates the appropriate motor torque, enters the semi-automatic operation mode, and starts to collect topographic data; a. Before the experiment begins, use a topograph to perform initial topographic measurements; b. After the experiment begins, according to the set water flow conditions, before replacing the spur dikes of different sizes every other cycle, use a topographic instrument to record the topographic changes at each stage; Step S53: After the test is completed, the collected terrain data is processed.

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