A local wave surge induced adjacent reef seabed topography evolution model test device and test method

Abstract

The application provides a local surge-induced adjacent reef seabed topography evolution model test device and test method, and the device comprises a soil box, a soil layer, a runner, a handle, a support, a fixing ring, a hose, an adjusting pipe, a pore pressure gauge, a displacement gauge and a partition plate. A constant pressure water head is set at one end to simulate a far-field water pressure, a hose fixed on the runner periodically rises and falls at the other end, a periodic surge pressure is formed in the soil layer on the right side of the partition plate, and the local scouring and far-field pressure seepage migration effects of the local surge on the adjacent reef seabed are simulated. The pore pressure gauge is used to determine the pore pressure change of the stratum to analyze the local scouring force and the far-field stratum seepage force change of the adjacent reef seabed, and the displacement gauge is used to determine the stratum displacement to analyze the local scouring deformation and the far-field pressure seepage migration law of the adjacent reef seabed. The influence of the local surge cycle, amplitude and pressure sudden increase point position on the surface morphology of the adjacent reef seabed is researched, and analysis basis is provided for the adjacent reef seabed topography evolution, far-sea island reef construction and erosion protection.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of research devices for the influence of swells on seabed, and particularly relates to a local swell-induced adjacent reef seabed topography evolution model test device and test method. BACKGROUND

[0002] Seawalls are located at the junction between the sea and land, and are a powerful barrier for coastline protection. Seawalls are subjected to short-crested waves all year round. At present, the observation and research of most short-crested waves in front of the dyke are still limited to their movement and dynamic characteristics, such as wave pressure and force on marine structures, thereby providing a basis for engineering design. When waves propagate in the sea, the stress induced by the waves causes dynamic fluctuations in seabed pressure, which causes excess pore water pressure in the soil body of the seabed and reduces the effective stress of the soil body, thereby causing the seabed to become unstable. Therefore, when designing and constructing marine engineering facilities, it is necessary to analyze the topography evolution of the foundation soil of the adjacent reef seabed under the action of wave loads.

[0003] It has been found through retrieval that the application No. CN202110635795.3 “A wave making device” provides a new design device for making waves, but this device is only a device for making waves by swinging a wave making plate, and does not study the influence of local swells hitting the adjacent reef seabed to induce seabed topography changes.

[0004] It has been found through retrieval that the paper “Analysis of dynamic response of seabed in front of dyke under wave action” studies the dynamic characteristics of the seabed in front of the dyke, but the paper only idealizes numerical simulation of waves, and does not further explore and develop research on displacement changes. Therefore, the existing technology is often only through motor wave making research and design, and does not involve the study of the local seabed erosion effect and far-field seepage force changes caused by manual runner wave making.

[0005] In recent years, the physical simulation research of adjacent reef seabed has developed rapidly, but these researches still have defects and deficiencies in reflecting the authenticity of actual swell load changes. Therefore, it is urgent to develop a wave making test equipment to study the influence of local swell period, amplitude and pressure sudden increase point position on the surface morphology of the adjacent reef seabed, and to provide analysis basis for adjacent reef seabed topography evolution, far sea island reef construction and erosion protection. SUMMARY

[0006] The present application aims to solve the deficiencies and defects of the prior art, and provides a local swell-induced adjacent reef seabed topography evolution model test device and test method. The runner wave making simulates the impact of swells on the coast, determines the influence of local swell period cycle on the adjacent reef seabed, and thereby evaluates the seabed pressure seepage migration caused by the development and diffusion process of the pore water pressure of the seabed.

[0007] A local surge induced adjacent reef seabed topography evolution model test device, including soil box 1, soil layer 2, runner 3, handle 4, support 5, fixed ring 6, hose 7, adjusting pipe 8, water tank 9, pore pressure gauge 10, displacement meter 11, baffle 12;

[0008] The rotating shaft of the runner 3 is fixed on the support 5, and the runner 3 is driven to rotate by the handle 4, and the support 5 can ensure the stable rotation of the runner;

[0009] The soil box 1 is made of organic glass, about 2m long and about 1m high, and a horizontal soil layer 2 is arranged inside to simulate the adjacent reef seabed, and the part above the soil layer 2 in the soil box is filled with water, and the soil layer 2 is immersed in water and tends to be saturated;

[0010] The baffle 12 is vertically placed at a distance of 0.15m from the right side of the soil box 1, which can limit the pressure change in the soil layer 2 on the right side of the baffle 12, form a local surge adjacent to the reef, and change the depth of the baffle 12 into the soil to adjust the position of the pressure surge point;

[0011] The hose 7 is filled with water, the left end is inserted into the soil box 1 and communicates with the water in the soil box 1, and the right end port is fixed on the runner 3 by the fixed ring 6 and can rotate with the runner 3;

[0012] The pore pressure gauge 10 and the displacement meter 11 are arranged uniformly in the soil layer 2 every 0.2-0.3m, and one layer is arranged every 0.2m in the depth direction, for monitoring the pore pressure change and displacement at each position;

[0013] The adjusting pipe 8 is a soft pipe, the left end is kept at a certain height to control the left water head and simulate the far-field water pressure, the left port is connected with the water tank 9, and the right port is connected with the soil box 1.

[0014] A local surge induced adjacent reef seabed topography evolution model test method, using the above-mentioned local surge induced adjacent reef seabed topography evolution model test device connection, the specific steps are as follows:

[0015] ①Preparation of clay with water content of 10%-30%, placed in the soil box 1, layered and compacted to form the soil layer 2, the soil box 1 is filled with water, and the soil layer 2 is immersed in water and tends to be saturated;

[0016] ②Connect the left water hole to the adjusting pipe 8, fix the height of the adjusting pipe 8, cause the water level difference, and the water in the soil box 1 can flow freely;

[0017] ③Insert the hose 7 into the soil box 1, fix the rotating shaft of the runner 3 on the support 5, and fix the support 5 on the ground;

[0018] ④Fill the hose 7 with water, and then fix the right port on the runner 3 by the fixed ring;

[0019] 5. By driving the rotating wheel 3 to rotate through the handle 4, the soft tube 7 is driven to circulate the water head to rise and fall, and a local surge pressure is generated on the soil layer 2 on the right side of the baffle;

[0020] 6. The data of the hole pressure gauge 10 and the displacement gauge 11 are observed to obtain the pressure seepage migration of the soil under the action of the local surge, and the surface morphology change caused by the erosion is observed.

[0021] 7. The rotating speed, height, diameter of the rotating wheel 3 and the soil insertion depth of the baffle 12 are changed, steps 1-6 are repeated, the influence of the local surge load with different frequencies and pressure ranges on the local erosion and far-field pressure seepage migration of the soil layer 2 is determined, and the influence law of the position change of the pressure sudden increase point is determined.

[0022] Further, a constant pressure water head is set at one end to simulate the far-field water pressure, and the soft tube fixed on the rotating wheel is periodically raised and lowered at the other end, thereby forming a periodic surge pressure in the soil layer on the right side of the baffle, simulating the local erosion and far-field pressure seepage migration of the adjacent reef seabed caused by the local surge. The hole pressure change of the stratum is measured by the hole pressure gauge to analyze the local erosion force and far-field stratum seepage force change of the adjacent reef seabed, and the stratum displacement is measured by the displacement gauge to analyze the local erosion deformation and far-field pressure seepage migration law of the adjacent reef seabed. The influence of the local surge cycle, amplitude and pressure sudden increase point position on the surface morphology of the adjacent reef seabed is studied, thereby providing analysis basis for the adjacent reef seabed topography evolution, far-sea island reef construction and erosion protection.

[0023] Advantages

[0024] The present application provides a local surge induced adjacent reef seabed topography evolution model test device and test method, which comprises a soil box, a soil layer, a rotating wheel, a handle, a support, a fixing ring, a soft tube, an adjusting tube, a hole pressure gauge, a displacement gauge and a baffle. A constant pressure water head is set at one end to simulate the far-field water pressure, and the soft tube fixed on the rotating wheel is periodically raised and lowered at the other end, thereby forming a periodic surge pressure in the soil layer on the right side of the baffle, simulating the local erosion and far-field pressure seepage migration of the adjacent reef seabed caused by the local surge. The hole pressure change of the stratum is measured by the hole pressure gauge to analyze the local erosion force and far-field stratum seepage force change of the adjacent reef seabed, and the stratum displacement is measured by the displacement gauge to analyze the local erosion deformation and far-field pressure seepage migration law of the adjacent reef seabed. The influence of the local surge cycle, amplitude and pressure sudden increase point position on the surface morphology of the adjacent reef seabed is studied, thereby providing analysis basis for the adjacent reef seabed topography evolution, far-sea island reef construction and erosion protection.

[0025] The advantages of the present application are as follows:

[0026] 1. The test device for generating surge by rotating wheel simulates the erosion effect of the local surge of the adjacent reef on the stratum near the reef, and causes the erosion deformation of the local seabed of the adjacent reef;

[0027] 2. The pore pressure and horizontal displacement of the seabed are finally determined by using a pore pressure gauge and a displacement gauge, and the local erosion deformation of the seabed of the adjacent reef and the migration law of the far-field pressure seepage are simulated and analyzed.

[0028] 3. The rotation speed, height, diameter of the runner and the insertion depth of the inserted plate are changed, the test is repeated, and the influence of the local surge period, amplitude and pressure sudden increase point position on the surface morphology of the seabed of the adjacent reef is researched, so as to provide analysis basis for the topographic evolution of the seabed of the adjacent reef, the construction and erosion protection of the far sea island reef. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a device structure schematic diagram of the application;

[0030] Figure 2 It is a top view of the soil box;

[0031] Label explanation: soil box 1, soil layer 2, runner 3, handle 4, support 5, fixed ring 6, hose 7, adjusting pipe 8, water tank 9, pore pressure gauge 10, displacement gauge 11, partition plate 12. DETAILED DESCRIPTION

[0032] The application will be further described below in combination with the drawings and examples.

[0033] As shown in the drawings, Figure 1 A local surge induced adjacent reef seabed topographic evolution model test device, which comprises a soil box 1, a soil layer 2, a runner 3, a handle 4, a support 5, a fixed ring 6, a hose 7, an adjusting pipe 8, a water tank 9, a pore pressure gauge 10, a displacement gauge 11 and a partition plate 12.

[0034] The rotating shaft of the runner 3 is fixed on the support 5, the runner 3 is driven to rotate through the handle 4, and the support 5 can ensure the stable rotation of the runner;

[0035] The soil box 1 is made of organic glass, about 2m long and about 1m high, and a horizontal soil layer 2 is arranged inside to simulate the adjacent reef seabed, and the part above the soil layer 2 in the soil box is filled with water, and the soil layer 2 is immersed in water and tends to be saturated;

[0036] The partition plate 12 is vertically placed at a distance of 0.15m from the right side of the soil box 1, can limit the pressure change in the soil layer 2 on the right side of the partition plate 12, form a local surge of the adjacent reef, and change the insertion depth of the partition plate 12 to adjust the position of the pressure sudden increase point;

[0037] The hose 7 is filled with water, the left end is inserted into the soil box 1 and communicates with the water in the soil box 1, and the right end is fixed on the runner 3 through the fixed ring 6 and can rotate with the runner 3;

[0038] The pore pressure gauge 10 and the displacement gauge 11 are arranged in the soil layer 2 at intervals of 0.2-0.3 m, and are arranged in layers at intervals of 0.2 m in the depth direction, for monitoring the pore pressure change and displacement at each position;

[0039] The adjusting pipe 8 is a soft pipe, the left end of which is kept at a certain height to control the water head on the left side, simulate the far-field water pressure, and is connected with the water tank 9 at the left port and connected with the soil tank 1 at the right port.

[0040] A local surge-induced adjacent reef seabed topography evolution model test method, which is connected with the above-mentioned local surge-induced adjacent reef seabed topography evolution model test device, and the specific steps are as follows:

[0041] ①Preparation of clay with a water content of 10%-30% and placement in the soil tank 1, layered compaction to form the soil layer 2, and the soil tank 1 is filled with water, and the soil layer 2 is saturated by water immersion;

[0042] ②Connect the left water hole to the adjusting pipe 8, fix the height of the adjusting pipe 8, cause the water level difference, and the water in the soil tank 1 can flow freely;

[0043] ③Insert the hose 7 into the soil tank 1, and fix the rotating shaft of the runner 3 on the support 5, and fix the support 5 on the ground;

[0044] ④Fill the hose 7 with water, and then fix the right port to the runner 3 through the fixing ring;

[0045] ⑤Drive the runner 3 to rotate through the handle 4, drive the water head of the hose 7 to circulate up and down, and generate local surge pressure on the right side of the soil layer 2 of the baffle;

[0046] ⑥Observe the data of the pore pressure gauge 10 and the displacement gauge 11 to obtain the pressure seepage migration of the soil body under the action of the local surge, and observe the surface morphology change caused by the erosion effect.

[0047] ⑦Change the rotating speed, height, diameter size of the runner 3 and the depth of the insertion plate 12, repeat steps ①-⑥, determine the influence of local surge load of different frequencies and pressure ranges on the local erosion and far-field pressure seepage migration of the soil layer 2, and determine the influence law of the position change of the pressure sudden increase point.

[0048] The above-mentioned is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principle of the present application, a number of improvements and substitutions can be made, which should be considered as the protection scope of the present application.

Claims

1. A model test device for localized swell-induced seabed topography evolution of adjacent reefs, characterized in that, Includes soil box (1), soil layer (2), wheel (3), handle (4), bracket (5), fixing ring (6), hose (7), regulating pipe (8), water tank (9), pore pressure gauge (10), displacement gauge (11), and partition (12); The rotating shaft of the rotating wheel (3) is fixed on the bracket (5), and the rotating wheel (3) is driven to rotate by the handle (4); The soil box (1) is made of plexiglass, 2m long and 1m high, with a horizontal soil layer (2) inside to simulate the seabed of the adjacent reef. The part above the soil layer inside the soil box is filled with water, and the soil layer (2) is saturated by water. The partition (12) is placed vertically 0.15m away from the right side of the soil box (1) to limit the pressure change in the soil layer (2) to the right side of the partition (12), forming a local swell on the adjacent reef. Changing the depth of the partition into the soil can adjust the position of the pressure surge point. The hose (7) is filled with water. Its left end is inserted into the soil box (1) and communicates with the water in the soil box (1). The right end of the hose is fixed to the rotating wheel (3) by a fixing ring (6) and can rotate with the rotating wheel (3). The pore pressure gauge (10) and displacement gauge (11) are arranged alternately in the same horizontal layer. The pore pressure gauge (10) and displacement gauge (11) are evenly arranged in the soil layer (2) at intervals of 0.2m to 0.3m. In the depth direction, the pore pressure gauge (10) and displacement gauge (11) are arranged in multiple layers, and the arrangement of each layer is consistent. The arrangement interval between two adjacent layers is 0.2m, which is used to monitor the pore pressure change and displacement at each location. The regulating pipe (8) is a soft pipe with a certain height on the left end to control the water head on the left side and simulate the far-field water pressure. The left port is connected to the water tank (9) and the right port is connected to the soil tank (1).

2. A model test method for the evolution of seabed topography of adjacent reefs induced by localized swells, characterized in that, The experimental apparatus for modeling seabed topography evolution induced by localized swells as described in claim 1 comprises the following specific steps: ① Prepare cohesive soil with a water content of 10% to 30%, place it in a soil box (1), compact it in layers to form a soil layer (2), fill the part above the soil layer in the soil box (1) with water, and the soil layer (2) is saturated by water. ② Connect the water hole on the left side to the regulating pipe (8), fix the height of the regulating pipe (8), create a water level difference, and the water in the soil box (1) can flow freely; ③ Insert the hose (7) into the soil box (1), fix the shaft of the rotating wheel (3) on the bracket (5), and fix the bracket (5) on the ground; ④ Fill the hose (7) with water, and then fix the right end of the hose to the wheel (3) with a fixing ring; ⑤ Drive the rotating wheel (3) to rotate by the handle (4), which will cause the water head of the hose (7) to rise and fall in a cycle, generating local surging pressure on the soil layer (2) on the right side of the partition. ⑥ Observe the data of the pore pressure gauge (10) and displacement gauge (11) to obtain the soil pressure seepage migration under the action of local surge waves, and observe the changes in landform caused by erosion. ⑦ Change the rotation speed, height and diameter of the impeller (3) and the depth of the partition (12) into the soil, repeat steps ① to ⑥, determine the influence of local surge loads of different frequencies and pressure ranges on the local erosion and far-field pressure seepage migration of the soil layer (2), and determine the influence law of the change of the position of the pressure surge point.

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