Permeable cover and model soil box for preventing soil leakage in underwater shaking table test

Abstract

The present invention provides a permeable cover plate for preventing soil leakage of an underwater vibration table test model soil box and an underwater vibration table test model soil box including the permeable cover plate for preventing soil leakage, and belongs to the technical field of test devices. The present invention includes a rigid cover plate with a hole in the middle; a flexible permeable dense net laid on the hole; a rigid structure connecting ring arranged in the hole and connected to the rigid cover plate through the flexible permeable dense net. The permeable cover plate of the present invention has the function of preventing the soil from rising due to the impact of the boundary soil on the side wall of the soil box, and the design of the flexible permeable dense net can ensure that the water pressure inside and outside the soil box is consistent and the structural displacement is not restricted. Compared with a completely flexible permeable dense net, the present invention can reduce the influence of surface undulation on the wave and flow field. The test model soil box can more accurately simulate the real seabed environment and avoid premature failure of the soil and damage to the test structure caused by soil leakage.

Description

Technical Field

[0001] The present invention relates to the technical field of test devices, and in particular to a permeable cover plate for preventing soil leakage of an underwater vibration table test model soil box and an underwater vibration table test model soil box comprising the permeable cover plate. Background Art

[0002] According to the existing earthquake damage investigation results, marine engineering structures are more susceptible to damage under the combined action of earthquakes, waves and currents, but the structural stress and failure mechanism is still unclear. In addition, under the action of dynamic loads, the pore water pressure in the seabed foundation soil increases and the effective stress decreases, resulting in the weakening and liquefaction of the seabed foundation soil; at the same time, the action of waves and currents will also cause scouring and damage to the seabed foundation soil. Under the combined action of earthquakes, waves and currents, the bearing capacity of the seabed foundation soil is complex, and the soil-structure interaction is obvious. Therefore, when exploring the stress mechanism of marine engineering structures under the combined action of earthquakes, waves and currents and conducting safety assessments on such structures, the influence of soil-structure interaction needs to be considered. At present, underwater shaking table model tests are one of the important means to study the stress mechanism of marine engineering structures under the combined action of earthquakes, waves and currents. When conducting structural shaking table tests considering soil-structure interaction, model soil boxes are often used to simulate the foundation soil. The technical methods for conducting the above two types of tests separately are relatively mature. However, there are still problems in the test when using the shaking table test model soil box to simulate the seabed foundation soil in the underwater shaking table model test.

[0003] In the underwater shaking table model test using a model soil box, the soil box is located below the water surface, the soil is in a saturated state, and the effective stress of the soil is smaller than that of the unsaturated soil. Under the action of dynamic loads, there are soil leakage phenomena such as the surface soil floating up or the boundary soil hitting the side wall of the soil box and rising up. The flowing water carries the rising soil out of the soil box, which eventually leads to a rapid reduction of the soil in the soil box and the loss of its original bearing capacity. In the real environment, although the soil surface will be scoured, other soil particles will be deposited, and there will be no large-scale loss of soil. Therefore, this phenomenon is not a normal test phenomenon and measures need to be taken to avoid it.

[0004] In summary, in order to simulate the real marine environment and ensure the effectiveness of the underwater shaking table test, it is necessary to design a new type of soil box to solve the problem of soil leakage when the model soil box is used to simulate the seabed foundation soil in the underwater shaking table model test. Summary of the invention

[0005] In view of this, in order to solve the technical problems of soil leakage such as the floating of the surface soil or the upward movement of the boundary soil body hitting the side wall of the soil box in the prior art, on the one hand, the present invention provides a permeable cover plate for preventing soil leakage of the model soil box of the underwater vibration table test. Compared with the completely rigid cover plate structure, the permeable cover plate has the function of preventing the upward movement of the soil body caused by the boundary soil body hitting the side wall of the soil box. At the same time, the design of the flexible permeable dense net can ensure that the water pressure inside and outside the soil box is consistent and the structural displacement is not restricted. Compared with the completely flexible permeable dense net, the present invention can reduce the influence of surface undulation on the wave flow field.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A water-permeable cover plate for preventing soil leakage from a model soil box for an underwater shaking table test, comprising:

[0008] A rigid cover plate with a hole in the middle;

[0009] A flexible water-permeable dense net, which is laid on the hole;

[0010] A rigid structure connecting ring is arranged in the hole and connected to the rigid cover plate through the flexible water-permeable net.

[0011] Preferably, the rigid structure connecting ring is formed by splicing two arc-shaped plates with connecting ears.

[0012] Preferably, the rigid structural connection ring and the flexible water-permeable net are connected via a structural connection ring connector;

[0013] The structural connection ring is provided on the side wall of the arc-shaped plate by a connection piece;

[0014] A rigid cover plate connector is provided near the hole, and the flexible water-permeable net is connected to the hole through the rigid cover plate connector.

[0015] Preferably, an elastic sealing strip is provided inside the rigid structure connecting ring.

[0016] Preferably, the flexible water-permeable dense net is made of high-density polyethylene or high-density polypropylene.

[0017] Preferably, the flexible water-permeable dense net is a net woven into knots.

[0018] Preferably, the rigid cover plate is provided with a rigid cover plate edge buckle for being snapped onto the soil box of the shaking table test model.

[0019] On the other hand, the present invention provides an underwater shaking table test model soil box for preventing soil leakage, comprising a rigid bottom plate, soil box side walls and the above-mentioned permeable cover plate;

[0020] The water-permeable cover plate for preventing soil leakage is covered on the box body formed by the rigid bottom plate and the side walls of the soil box.

[0021] Preferably, the model soil box is one of a rigid soil box, a flexible soil box or a layered shear type soil box, preferably a layered shear type soil box.

[0022] Preferably, the layered shear type soil box is composed of a multi-layer frame, and a water-permeable membrane is laid inside the layered shear type soil box to prevent soil particles from passing through the gaps of the multi-layer frame.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The permeable cover plate for preventing soil leakage of the model soil box for underwater vibration table test provided by the present invention is suitable for underwater vibration table model test, ensuring that during the underwater vibration table model test with the simulated soil box, the soil in the model soil box will not leak out due to impact on the side wall or water scouring, thereby avoiding premature damage to the structure caused by a rapid reduction in soil volume.

[0025] (2) Compared with a completely rigid cover structure, the water-permeable cover designed by the present invention can prevent the soil from rising due to the impact of the boundary soil on the side wall of the soil box. At the same time, the design of the flexible water-permeable net can ensure that the water pressure inside and outside the soil box is consistent and the structural displacement is not restricted. Compared with a completely flexible water-permeable net, the present invention can reduce the impact of surface undulation on the wave and flow field.

[0026] (3) The permeable cover plate designed by the present invention to prevent soil leakage can be combined with the existing model soil box used for waterless vibration table test through the rigid cover plate edge buckle, so that the molded soil box is transformed into a soil box that can be used for underwater vibration table test. At the same time, it is easy to disassemble and the original function of the soil box is not affected after disassembly.

[0027] (4) The rigid structural connecting ring designed in the present invention is formed by connecting two arc-shaped plates with connecting ears. After the structural model is installed, the flexible water-permeable dense net can be fixed on the structure to avoid the existence of the cover plate affecting the model installation.

[0028] (5) The present invention can change the size, shape and number of the arc-shaped plates according to the cross-sectional form at the water-soil interface of the structure, thereby ensuring that the present invention can be applied to underwater vibration table tests of various marine structures.

[0029] (6) The rigid structure connecting ring designed in the present invention is provided with an elastic sealing strip inside, which ensures a tight connection with the structure while avoiding excessive local stress and surface wear caused by the extrusion of the rigid structure connecting ring during the movement of the structure.

[0030] (7) Connectors are provided between the various parts of the present invention to ensure effective connection between the various parts while making the manufacturing, installation, and disassembly processes simple and convenient.

[0031] (8) The present invention is suitable for underwater shaking table model tests of marine structures taking into account soil-structure interaction, and the use of the soil box can more accurately simulate the real seabed environment and avoid premature failure of the soil and damage to the test structure caused by soil leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a soil box for an underwater shaking table test model for preventing soil leakage provided by the present invention;

[0033] Figure 2 A schematic diagram of the structure of a shaking table test model soil box provided by the present invention;

[0034] Figure 3 A schematic structural diagram of a water-permeable cover plate for preventing soil leakage provided by the present invention;

[0035] Figure 4 A cross-sectional view of a water-permeable cover plate for preventing soil leakage provided by the present invention;

[0036] Figure 5 A schematic diagram of the structure of the flexible water-permeable dense net provided by the present invention;

[0037] Figure 6 A schematic diagram of the structure of the rigid structure connecting ring provided by the present invention;

[0038] Figure 7 An exploded schematic diagram of the rigid structure connecting ring provided by the present invention;

[0039] Figure 8 A schematic diagram of the structure of the connecting piece for the structural connecting ring and the rigid cover plate provided by the present invention;

[0040] Fig. 9 It is a schematic diagram of the structure of the edge buckle of the rigid cover plate of the present invention;

[0041] Fig.10 A schematic diagram of the structure of a layered shear type model soil box provided by the present invention;

[0042] Fig.11 Another structural schematic diagram of the layered shear type model soil box provided by the present invention;

[0043] Fig.12 Schematic diagram of the movement of soil in the soil box of the shaking table test model Figure 1 ;

[0044] Fig.13 Schematic diagram of soil movement in the soil box of the shaking table test model Figure 2 .

[0045] In the figure, 1. soil box of shaking table test model; 2. permeable cover plate to prevent soil leakage; 3. rigid bottom plate; 4. side wall of soil box; 5. rigid cover plate; 6. flexible permeable dense net; 7. rigid structural connecting ring; 8. arc plate; 9. connecting ear; 10. bolt; 11. connecting piece for structural connecting ring; 12. elastic sealing strip; 13. connecting piece for rigid cover plate; 14. rigid cover plate edge buckle; 15. layered shear type model soil box; 16. multi-layer frame; 17. permeable membrane. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] like Figure 3-4 As shown, the present invention provides a water-permeable cover plate 2 for preventing soil leakage of an underwater vibration table test model soil box 1, comprising:

[0050] The rigid cover plate 5 has a hole in the middle. The rigid cover plate 5 is preferably made of a watertight rigid material. The size is slightly larger than the size of the top layer of the simulated soil box to ensure that it can cover the opening of the soil box and has no gaps at the border. The hole in the middle is used to place the flexible water-permeable dense net 6 to ensure water permeability. The edge of the rigid cover plate 5 is provided with a rigid cover plate edge buckle 14 to connect with the shaking table test model soil box 1.

[0051] like Figure 5 As shown, the flexible water-permeable dense net 6 is laid on the hole, wherein the flexible water-permeable dense net 6 selects a suitable aperture according to the soil particle gradation in the soil box to ensure water permeability and prevent the surface soil from floating up; preferably, it is made of high-density polyethylene or high-density polypropylene. In order to avoid the tearing of the dense net due to structural movement during the test, the selected material must have the characteristics of solidity, durability, high tensile strength, and good toughness. At the same time, net knots are set during the weaving process to avoid linear knot opening. Preferably, the flexible water-permeable dense net 6 is a net woven with net knots, laid on the hole of the rigid cover plate 5, and the size is slightly larger than the hole to ensure that the displacement of the test structure is not restricted. The flexible water-permeable dense net 6 should select a suitable aperture according to the type and gradation of the soil model. While ensuring that the water pressure inside and outside the soil box is consistent, prevent the surface soil from floating up in large quantities.

[0052] The flexible water-permeable net 6 is arranged at the opening of the rigid cover plate 5. On the one hand, it ensures that the cover plate does not affect the water pressure inside and outside the soil box, ensuring accurate simulation of the soil environment; on the other hand, it prevents the central soil from floating up under the action of dynamic load and reduces soil loss.

[0053] The rigid structure connecting ring 7 is arranged in the hole and connected to the rigid cover plate 5 through the flexible water-permeable dense net 6. It is preferably made of the same material as the rigid cover plate 5 and is made into an annular structure with the same cross-sectional shape as the test structure and slightly larger size.

[0054] like Figure 6-7 As shown, in the present invention, an embodiment of a rigid structure connecting ring 7 is provided, wherein the rigid structure connecting ring 7 is formed by splicing two arc-shaped plates 8 with connecting ears 9, and specifically can be:

[0055] The rigid structure connecting ring 7 is formed by two arc-shaped plates 8 with connecting ears 9 connected by bolts 10 (such as Figure 6 As shown), the edges of the rigid structure connecting ring 7 are evenly arranged with structural connecting ring connectors 11, the inner dimensions are slightly larger than the test model dimensions, and an elastic sealing strip 12 is preferably arranged inside.

[0056] like Figure 8-9 As shown, in the present invention, the rigid structure connecting ring 7 is connected to the flexible water-permeable net 6 through a structural connecting ring connecting member 11; the structural connecting ring connecting member 11 is arranged on the side wall of the arc plate 8;

[0057] A rigid cover plate connector 13 is provided near the hole, and the flexible water-permeable net 6 is connected to the hole through the rigid cover plate connector 13 .

[0058] Preferably, the edge of the rigid structure connection ring 7 is evenly arranged with the structural connection ring connector 11, and the steel wire rope is fixed to fix the flexible water-permeable dense net 6. The flexible water-permeable dense net 6 is strung with the steel wire rope, and the edge of the hole of the rigid cover plate 5 is evenly arranged with the rigid cover plate connector 13, and the steel wire rope is fixed to fix the flexible water-permeable dense net 6.

[0059] In the present invention, an elastic sealing strip 12 is provided inside the rigid structure connecting ring 7 to ensure a tight and reliable connection with the structure without causing damage to the structure.

[0060] In the present invention, the rigid cover plate 5 is provided with a rigid cover plate edge buckle 14 for being snapped onto the shaking table test model soil box 1 .

[0061] The permeable cover plate 2 for preventing soil leakage provided by the present invention is more advantageous than the methods of simply using a rigid cover plate 5 and simply using a flexible permeable dense net 6 to prevent soil leakage. Simply using a rigid cover plate 5, on the one hand, limits the translational displacement of the structure, and on the other hand, the rigid cover plate 5 is impermeable, and the water pressure inside and outside the soil box is different, which causes the soil model to simulate the real seabed soil environment with a reduced accuracy. Simply using a flexible permeable dense net 6, in order to ensure that the displacement of the structure is not restricted, the overall size should be larger than the cross-sectional size of the soil box, resulting in the flexible permeable dense net 6 partially bulging when the boundary soil hits the side wall 4 of the soil box and rises, affecting the wave flow field state near the structure, and then affecting the hydrodynamic effect on the structure. The permeable cover plate 2 for preventing soil leakage of the present invention, while preventing the boundary soil from hitting the side wall 4 of the soil box and rising, ensures that the water pressure inside and outside the soil box is consistent and the displacement of the structure is not restricted.

[0062] On the other hand, the present invention provides an underwater shaking table test model soil box 1 to prevent soil leakage. Figure 1-2 As shown, it includes a rigid bottom plate 3, a soil box side wall 4 and the above-mentioned permeable cover plate;

[0063] The water-permeable cover plate 2 for preventing soil leakage is covered on the box body formed by the rigid bottom plate 3 and the side wall 4 of the soil box.

[0064] The rigid bottom plate 3 should have a relatively high bearing capacity. Preferably, the rigid bottom plate 3 can be in the form of a double-layer steel plate with ribs.

[0065] like Figure 10-11As shown, in the present invention, the type and cross-section of the shaking table test model soil box 1 should be selected according to the test requirements. The model soil box is one of a rigid soil box, a flexible soil box or a layered shear type soil box, preferably a layered shear type soil box, which can better simulate the shear deformation conditions of the soil boundary. The cross-section of the model soil box can be quadrilateral, circular or polygonal.

[0066] The soil box 1 of the shaking table test model should be of appropriate size according to the size of the shaking table and the test model. Under the premise of saving costs, the size effect and boundary effect of the soil model should be small, and the soil box size / structure size should be ≥ 5. This can effectively simulate the constraint of the soil on the structure, and correctly reflect the stress state of the structure, ensuring the reliability of the test results.

[0067] In the present invention, the layered shear type soil box is composed of a multi-layer frame 16 , and a water-permeable membrane 17 is laid inside the layered shear type soil box to prevent soil particles from passing through the gaps of the multi-layer frame 16 .

[0068] The multi-layer frame 16 of the layered shear type model soil box 15 can move relative to each other. When the boundary soil hits the side wall 4 of the soil box, the impact force can be weakened and the volume of the rising soil can be reduced.

[0069] like Fig.11 As shown, the outer side of the multi-layer frame 16 is a quadrilateral, which has a better effect under single sport conditions compared to a circle or a polygon; the inner frame is an octagon, which improves the problem of poor lateral bearing capacity of the quadrilateral frame.

[0070] like Fig.11 As shown, a permeable membrane 17 is laid inside the layered shear type model soil box 15 to prevent soil particles from passing through the gaps of the multi-layer frame 16 and simulate the boundary permeability conditions of the soil body.

[0071] like Figure 12-13 As shown, a rigid cover plate edge buckle 14 is provided at the edge of the rigid cover plate 5 to connect with the top frame of the layered shear type model soil box 15 to prevent Fig.12 The phenomenon that the middle boundary soil hits the side wall 4 of the soil box and rises.

[0072] The construction process of the underwater vibration table test model soil box 1 for preventing soil leakage provided by the present invention is divided into the following steps:

[0073] (1) Arrange the test structure foundation and soil model in the shaking table test model soil box 1;

[0074] (2) Fix the rigid cover plate 5 on the shaking table test model soil box 1, and clamp the edge buckle of the rigid cover plate;

[0075] (3) After the structure is arranged and connected to the foundation, a flexible water-permeable mesh 6 is laid around the opening of the structure and connected to the rigid cover plate and the rigid structure connection ring 7 through the rigid cover plate connection piece 13 and the structure connection ring connection piece 11 respectively;

[0076] (4) Fix the rigid structure connecting ring 7 to the structure.

[0077] During the installation process, the rigid cover plate is first fixed to the simulated soil box using the edge buckles of the rigid steel plate. After the structural model is installed, the flexible water-permeable net 6 is connected to the rigid cover plate and the rigid structural connecting ring 7. Finally, the structural connecting ring is clamped to complete the overall installation work.

[0078] The above are only preferred specific implementations of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and improved concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A water-permeable cover plate for preventing soil leakage in a model soil box for an underwater shaking table test, characterized in that: include: A rigid cover plate with a hole cut into the middle; A flexible water-permeable dense net is laid on the hole, and its size is larger than the hole. The flexible water-permeable dense net has a suitable aperture selected according to the soil particle gradation in the soil box, so as to ensure that the water pressure inside and outside the soil box is consistent; A rigid structure connecting ring is arranged in the hole and connected to the rigid cover plate through the flexible water-permeable net.

2. A water-permeable cover plate for preventing soil leakage of a model soil box for an underwater shaking table test according to claim 1, characterized in that: The rigid structure connecting ring is formed by splicing two arc-shaped plates with connecting ears.

3. A water-permeable cover plate for preventing soil leakage of a model soil box for underwater shaking table test according to claim 2, characterized in that: The rigid structural connection ring and the flexible water-permeable dense net are connected with a connection piece through the structural connection ring; The structural connection ring is provided on the side wall of the arc-shaped plate by a connection piece; A rigid cover plate connector is provided near the hole, and the flexible water-permeable net is connected to the hole through the rigid cover plate connector.

4. The water-permeable cover plate for preventing soil leakage of a model soil box for an underwater shaking table test according to claim 1, characterized in that: An elastic sealing strip is arranged inside the rigid structure connecting ring.

5. The water-permeable cover plate for preventing soil leakage of the model soil box for underwater shaking table test according to claim 1, characterized in that: The flexible water-permeable dense net is made of high-density polyethylene or high-density polypropylene.

6. The water-permeable cover plate for preventing soil leakage of a model soil box for underwater shaking table test according to claim 1, characterized in that: The flexible water-permeable dense net is a net woven into a knotted net.

7. A water-permeable cover plate for preventing soil leakage of a model soil box for underwater shaking table test according to any one of claims 1 to 6, characterized in that: The rigid cover plate is provided with a rigid cover plate edge buckle for being clamped to the soil box of the shaking table test model.

8. An underwater shaking table test model soil box to prevent soil leakage, characterized in that: It comprises a rigid bottom plate, a soil box side wall and a permeable cover plate for preventing soil leakage according to any one of claims 1 to 7; The water-permeable cover plate for preventing soil leakage is covered on the box body formed by the rigid bottom plate and the side walls of the soil box.

9. The underwater shaking table test model soil box for preventing soil leakage according to claim 8, characterized in that: The model soil box is one of a rigid soil box, a flexible soil box or a layered shear type soil box.

10. The underwater shaking table test model soil box for preventing soil leakage according to claim 9, characterized in that: The model soil box is a layered shear type soil box.

11. The underwater shaking table test model soil box for preventing soil leakage according to claim 9, characterized in that: The layered shearing type soil box is composed of a multi-layer frame, and a water-permeable membrane is laid inside the layered shearing type soil box to prevent soil particles from passing through the gaps of the multi-layer frame.

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