Experimental simulation device and method for slope seabed

Abstract

The present invention relates to a preparation device and method for simulating seabed soil, and in particular to an experimental simulation device and method for a sloped seabed. The simulation device includes a soil trough, in which an inclined rigid top water filter layer is arranged, and the top water filter layer and the inner wall of the soil trough form a closed space for accommodating soil media; an injection port and a first drainage port are arranged on the top water filter layer, and a constraint mechanism is connected above the top water filter layer, and the constraint mechanism drives the top water filter layer to only undergo a vertical translational displacement. The present invention has an ingenious structural design and is easy to operate. It can simulate a sloped seabed formed by natural deposition, and can obtain a sloped seabed with different consolidation degrees or different slopes, which will be used for the study of transverse slope pipeline instability of deep-sea marine pipelines.

Description

Technical Field

[0001] The invention relates to a device and method for preparing simulated seabed soil, and in particular to a device and method for experimental simulation of a slope seabed. Background Art

[0002] As my country's offshore oil and gas resource exploitation moves towards the deep sea, submarine pipelines often encounter sloping seabed terrain. The existence of a sloping seabed will greatly reduce the in-situ stability of submarine structures, making them more susceptible to in-situ sliding instability under environmental loads. Given the complexity of deepwater environmental loads and seabed soil conditions, the in-situ stability of pipelines on deep-sea soft clay sloping seabeds has become a focus of attention in the field of marine engineering. Physical model experiments in the laboratory are an important means of conducting this research, and the preparation of soft clay sloping seabeds is one of its key links.

[0003] The existing seabed soil preparation devices and methods are mainly aimed at the horizontal seabed. At present, there is no relatively complete and reliable experimental simulation device for the slope seabed. Deep-sea soft clay sediments usually have typical characteristics such as small particle size, low density, and poor permeability. As a result, the self-weight consolidation of the reshaped clay takes a long time; the bed surface and consolidation degree distribution obtained by gravity consolidation or traditional vacuum consolidation are all in the horizontal direction, which is difficult to simulate the slope seabed formed by natural sedimentation. Summary of the invention

[0004] The present invention provides an experimental simulation device and method for a soft clay slope seabed, so as to alleviate the problem that the existing seabed soil preparation device and method are mainly aimed at the situation of a horizontal seabed and it is difficult to simulate a slope seabed formed by natural deposition.

[0005] In order to alleviate the above technical problems, the technical solution provided by the present invention is:

[0006] An experimental simulation device for a sloped seabed comprises an earth trough in which an inclined rigid top water filter layer is arranged, the top water filter layer and the inner wall of the earth trough forming a closed space for accommodating an earth medium; an injection port and a first drainage port are arranged on the top water filter layer, a constraint mechanism is connected above the top water filter layer, and the constraint mechanism is configured to drive the top water filter layer to undergo only a vertical translational displacement.

[0007] Furthermore, the constraint mechanism includes a constraint frame, which includes a horizontally arranged constraint frame cross bar and a first constraint frame longitudinal bar and a second constraint frame longitudinal bar of unequal length arranged at both ends of the constraint frame cross bar, and the lower ends of the first constraint frame longitudinal bar and the second constraint frame longitudinal bar are connected to the top water filtration layer.

[0008] Furthermore, the restraint mechanism also includes a mounting frame, which includes a horizontally arranged mounting frame cross bar and two equal-length mounting frame longitudinal bars arranged at both ends of the mounting frame cross bar. The mounting frame cross bar is perpendicular to the mounting frame longitudinal bar, and the bottom end of the mounting frame longitudinal bar is connected to the top of the side wall of the soil trough.

[0009] Furthermore, the restraint mechanism also includes a connecting member, which includes at least two connecting rods that are cross-arranged and rotatably connected, and two ends of the connecting rods are respectively hinged to the restraint frame cross bar and the mounting frame cross bar.

[0010] Furthermore, the top water filtration layer includes a geotextile laid on top of the soil medium, a sand water guide belt laid on top of the geotextile, a porous steel plate arranged in the sand water guide belt and a sealing cloth laid on top of the sand water guide belt, reinforcing ribs are arranged above the porous steel plate, and the porous steel plate is connected to the constraint mechanism.

[0011] Furthermore, a filter layer is arranged on the side and / or bottom of the soil trough, and the filter layer is connected to the second drainage outlet.

[0012] Furthermore, a pore pressure sensor and / or a scale and / or a glass observation window is arranged on the side wall.

[0013] Furthermore, it also includes a vacuum consolidation device, which is connected to the first drain port and / or the second drain port through a drainage conduit.

[0014] Furthermore, a vertical partition plate is arranged in the soil trough, and the partition plate divides the soil trough into separate areas isolated from each other.

[0015] A preparation method using the simulated slope seabed.

[0016] The beneficial effects of the experimental simulation device and method for soft clay slope seabed in the present invention are analyzed as follows:

[0017] The present invention establishes a relatively complete and reliable experimental simulation device for a sloped seabed. An inclined rigid top water filter layer is arranged inside a soil trough. The top water filter layer and the inner wall of the soil trough form a closed space for accommodating soil media. An injection port and a first drainage port are arranged on the top water filter layer. A constraint mechanism is connected above the top water filter layer. The constraint mechanism drives the top water filter layer to only undergo a vertical translational displacement.

[0018] The soil medium is filled in the soil trough through the injection port. When the counterweight is evenly piled on the top filter layer of the soil trough, the pore water in the soil permeates upward under the pressure, passes through the top filter layer, and flows out through the first drain port without taking away the soil in the soil trough. This is the same as the process in which the pore water in the soil seeps upward under the pressure of the soil body's own weight under natural conditions and is discharged to the free surface. It should be noted that the soil medium is clay or silt stirred into a mud state. The top filter layer is set as a rigid material to keep the upper surface of the soil body in a plane during the consolidation process. The constraint mechanism drives the top filter layer to only undergo a vertical translational displacement, thereby ensuring that the soil body maintains a fixed inclination slope during the settlement process. In summary, this device can realize the preparation of a slope seabed, and different degrees of consolidation can be obtained by controlling the loading amount or loading time of the piled material; and slope seabeds with different slopes can be obtained by adjusting the inclination angle of the top filter layer.

[0019] The invention has an ingenious structural design and is easy to operate. It can simulate a slope seabed formed by natural sedimentation and obtain slope seabeds with different consolidation degrees or different slopes, and will be used for the study of transverse slope pipeline instability in deep-sea marine pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic structural diagram of an experimental simulation device for a sloped seabed provided in an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of the top water filtration layer;

[0023] Figure 3 It is a schematic diagram of the structure of the lateral filter layer;

[0024] Figure 4 It is the structural schematic diagram of the bottom filter layer;

[0025] Figure 5 This is a schematic diagram of the structure of the soil trough separation area.

[0026] icon:

[0027] 100-soil trough; 200-top water filter layer; 300-reverse filter layer; 400-soil medium; 500-restraint mechanism;

[0028] 001-first drain port; 002-injection port; 003-overflow valve; 004-separation area; 005-second drain port;

[0029] 210-porous steel plate; 220-sealing cloth; 211-reinforcement rib; 230-geotextile; 240-sand water guide belt;

[0030] 510-constraint frame; 520-connector; 530-mounting frame; 531-mounting frame cross bar; 532-mounting frame longitudinal bar; 511-constraint frame cross bar; 512-first constraint frame longitudinal bar; 513-second constraint frame longitudinal bar; 521-connecting rod;

[0031] 600-pore pressure sensor; 700-glass observation window; 800-vacuum consolidation device; 900-ruler;

[0032] 810-negative pressure pump; 820-pressure gauge; 830-valve; 840-pressure servo control system;

[0033] 1000 - partition plate; 1100 - bottom plate; 1200 - side wall; 1210 - inner wall of side wall; 1220 - outer wall of side wall; 1300 - drainage duct; 1310 - first drainage duct; 1320 - second drainage duct. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described implementation is only a part of the implementation of the present invention, not all of the implementation. Based on the implementation of the present invention, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Physical quantities in formulas, if not separately marked, should be understood as basic quantities of the base units of the International System of Units, or derived quantities derived from the basic quantities through mathematical operations such as multiplication, division, differentiation or integration.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it 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.

[0037] As my country's offshore oil and gas resource exploitation moves towards the deep sea, submarine pipelines often encounter sloping seabed terrain. The existence of a sloping seabed will greatly reduce the in-situ stability of submarine structures, making them more susceptible to in-situ sliding instability under environmental loads. Given the complexity of deepwater environmental loads and seabed soil conditions, the in-situ stability of pipelines on deep-sea soft clay sloping seabeds has become a focus of attention in the field of marine engineering. Physical model experiments in the laboratory are an important means of conducting this research, and the preparation of soft clay sloping seabeds is one of its key links.

[0038] The existing seabed soil preparation devices and methods are mainly aimed at the horizontal seabed. At present, there is no relatively complete and reliable experimental simulation device for the slope seabed. Deep-sea soft clay sediments usually have typical characteristics such as small particle size, low density, and poor permeability. As a result, the self-weight consolidation of the reshaped clay takes a long time; the bed surface and consolidation degree distribution obtained by gravity consolidation or traditional vacuum consolidation are all in the horizontal direction, which is difficult to simulate the slope seabed formed by natural sedimentation.

[0039] In view of this, this embodiment provides an experimental simulation device for a sloped seabed, please refer to Figures 1 to 5 The device includes an earth trough 100, in which an inclined rigid top water filter layer 200 is arranged, and the top water filter layer 200 and the inner wall of the earth trough 100 form a closed space for accommodating an earth medium 400; an injection port 002 and a first drainage port 001 are arranged on the top water filter layer 200, and a constraint mechanism 500 is connected above the top water filter layer 200, and the constraint mechanism 500 drives the top water filter layer 200 to only undergo a vertical translational displacement.

[0040] The soil medium 400 is filled in the soil trough 100 through the injection port 002. When the counterweight is evenly piled on the top water filter layer 200 of the soil trough 100, the pore water in the soil penetrates upward under the action of pressure, and after passing through the top water filter layer 200, it flows out from the first drainage port 001 without taking away the soil in the soil trough 100. In addition, since the top water filter layer 200 provided on the soil medium 400 is a rigid material, it is ensured that the upper surface of the soil body remains flat during the consolidation process. The constraint mechanism 500 drives the inclined top water filter layer 200 to only undergo vertical translational displacement, which ensures that the soil body can maintain a fixed inclination slope during the settlement process. Therefore, the preparation of a sloped seabed can be achieved.

[0041] In an optional solution of the present embodiment, an overflow valve 003 is provided on the top water filter layer 200, and the overflow valve 003 is provided on the higher end of the top water filter layer 200, and the injection port 002 is located lower than the overflow valve 003, thereby ensuring that when the overflow valve 003 begins to bubble, the soil trough 100 is filled with soil medium 400.

[0042] In an optional solution of the present embodiment, the constraint mechanism 500 includes a constraint frame 510, and the constraint frame 510 includes a horizontally arranged constraint frame cross bar 511 and a first constraint frame longitudinal bar 512 and a second constraint frame longitudinal bar 513 of unequal length arranged at both ends of the constraint frame cross bar 511. Preferably, the first constraint longitudinal bar 512 and the second constraint frame longitudinal bar 513 are perpendicular to the constraint frame cross bar 511. The lower ends of the first constraint longitudinal bar 512 and the second constraint frame longitudinal bar 513 are connected to the top water filter layer 200, and the unequal lengths of the first constraint longitudinal bar 512 and the second constraint frame longitudinal bar 513 can keep the top water filter layer 200 at a certain inclination. Preferably, the constraint frame cross bar 511, the first constraint longitudinal bar 512 and the second constraint frame longitudinal bar 513 can be set as telescopic rods, and the inclination of the top water filter layer 200 can be controlled by adjusting their lengths and the positions connected to the top water filter layer 200.

[0043] In an optional solution of this embodiment, the restraint mechanism 500 further includes a mounting frame 530, which includes a horizontally arranged mounting frame cross bar 531 and two equal-length mounting frame longitudinal bars 532 arranged at both ends of the mounting frame cross bar 531, the mounting frame cross bar 531 is perpendicular to the mounting frame longitudinal bars 532, and the bottom ends of the mounting frame longitudinal bars 532 are connected to the top of the side wall 1200 of the soil trough 100. The mounting frame 530 is used to restrain the restraint frame 510, and its function is to prevent the restraint frame 510 from rotating and only allowing translational displacement in the vertical direction.

[0044] In an optional solution of this embodiment, the constraint mechanism 500 further includes a connecting member 520, and the connecting member 520 includes at least two connecting rods 521 that are cross-arranged and rotatably connected. Preferably, the two connecting rods 521 are arranged to be equal in length. The upper end of one connecting rod 521 is hinged to the mounting frame cross bar 531, and the lower end is slidably connected to the constraint frame cross bar 511; the upper end of the other connecting rod 521 is slidably connected to the mounting frame cross bar 531, and the lower end is hinged to the constraint frame cross bar 511. The above-mentioned scissor fork lifting structure can drive the top water filter layer 200 located below to move in the up and down directions.

[0045] In the optional solution of this embodiment, please refer to Figure 2 The rigid top water filter layer 200 includes a geotextile 230 laid on the soil medium 400 and a sand water guide belt 240 laid on the geotextile 230. The geotextile 230 allows pore water to be discharged into the sand water guide belt 240 through the geotextile 230, while preventing particles of the soil medium 400 from entering the sand water guide belt 240 to block the drainage channel; the sand water guide belt 240 can evenly transfer the pressure of the weight piled on the top water filter layer 200 to the upper surface of the soil medium 400, and the pore water in the soil medium 400 seeps upward under the action of pressure and is discharged upward through the geotextile 230 and the sand water guide belt 240.

[0046] Furthermore, a porous steel plate 210 is arranged inside the sand water guide belt 240, and the porous steel plate 210 is connected to the constraint mechanism 500, so that the top water filter layer 200 can only move in the up and down directions by driving the constraint mechanism 500. The porous steel plate 210 can also be set as other rigid materials, and its function is to ensure that the upper surface of the soil body remains in a plane during the consolidation process. A reinforcing rib 211 is arranged above the porous steel plate 210, and the structure of the reinforcing rib 211 is preferably set as an L-shape, and the horizontal side of the reinforcing rib 211 is fixed on the porous steel plate 210. In addition to increasing the bending rigidity of the porous steel plate 210, the vertical side of the reinforcing rib 211 also plays a fixing role on the sand water guide belt 240, preventing the sand water guide belt 240 laid on the inclined porous steel plate 210 from sliding.

[0047] Furthermore, the top water filter layer 200 also includes a sealing cloth 220 laid on the sand water guide belt 240, and the sealing cloth 220 is sealed at the connection with the inner wall of the soil trough 100 to ensure that the top water filter layer 200 and the inner wall of the soil trough 100 form a sealed space. The surface of the sealing cloth 220 is provided with a first drain port 001, and the position of the first drain port 001 is preferably set at the lower end of the top water filter layer 200. When the heap consolidation method is adopted, the first drain port 001 is directly exposed in the water tank, so that the discharged pore water directly flows into the water tank.

[0048] The working process of the top water filter layer 200 is described in detail as follows:

[0049] When the loading consolidation method is adopted, a counterweight such as saturated sand is piled above the top water filter layer 200, and the sand water guide belt 240 can evenly transfer the pressure to the upper surface of the soil medium 400. The pore water in the soil medium 400 seeps upward under the pressure and is discharged into the sand water guide belt 240 through the geotextile 230. The particles in the soil medium 400 cannot enter the sand guide belt 240 due to the obstruction of the geotextile 230. Because the sealing cloth 220 is sealed and connected to the inner wall of the soil trough 100 to form a closed space, the pore water can only be discharged through the first drainage port 001 on the surface of the sealing cloth 220. During the pore water discharge process, when the soil medium 400 undergoes consolidation and settlement, the top water filter layer, which is set to be inclined, can only undergo vertical translational displacement under the action of the constraint mechanism 500. Under the pressure of the top water filter layer 200, the soil can maintain a fixed slope, and under the action of the porous steel plate 210, the upper surface of the soil remains flat during the consolidation process. By controlling the loading amount and loading time of the counterweight on the top water filter layer 200, a slope seabed with different consolidation degrees can be obtained.

[0050] In an optional solution of this embodiment, a filter layer 300 may be provided on the inner wall of the soil trough 100, and the filter layer 300 is connected to the second drainage port 005. There are many ways to set the filter layer 300 on the inner wall of the soil trough 100, for example:

[0051] Method 1: Set a filter layer 300 at the bottom of the soil trough 100, please refer to Figure 4 The bottom filter layer 300 includes a sand water guide belt 240 laid on the bottom plate 1100 and a geotextile 230 laid on the sand water guide belt 240. The second drain port 005 can be set on the bottom plate 1100. The soil medium 400 is above the geotextile 230.

[0052] Method 2: Set a filter layer 300 on the side of the soil trough 100, please refer to Figure 3 The side wall 1200 includes a side wall inner wall 1210 with holes and a side wall outer wall 1220, a gap is formed between the side wall inner wall 1210 and the side wall outer wall 1220, the lateral filter layer 300 includes a geotextile 230 arranged between the soil medium 400 and the side wall inner wall 1210 and a sand water guide belt 240 arranged between the side wall inner wall 1210 and the side wall outer wall 1220, and the second drainage outlet 005 can be arranged on the side wall 1200.

[0053] Method three: a filter layer 300 is set at the bottom and side of the soil trough 100. The structure of the filter layer 300 can refer to the structures in the above two methods. Among them, the more preferred second drain outlet 005 is set at the bottom of the side wall 1200 and connected to the bottom filter layer 300. The pore water of the bottom filter layer 300 and the side filter layer 300 can be discharged through the second drain outlet 005 at the same time.

[0054] It should be noted that any one of the above three methods can be selected.

[0055] The working process of the bottom filter layer 300 is described in detail as follows:

[0056] When the loading consolidation method is adopted, a counterweight such as saturated sand is piled above the top water filter layer 200, and the sand water guide belt 240 can evenly transfer the pressure to the upper surface of the soil medium 400. The pore water in the soil medium 400 seeps downward under the action of pressure and is discharged into the sand water guide belt 240 through the geotextile 230. The particles in the soil medium 400 cannot enter the sand guide belt 240 due to the obstruction of the geotextile 230, and the pore water is discharged through the second drainage port 005.

[0057] The working process of the lateral filter layer 300 is described in detail as follows:

[0058] When the loading consolidation method is adopted, a counterweight such as saturated sand is piled on top of the top water filter layer 200. The sand water guide belt 240 can evenly transfer the pressure to the upper surface of the soil medium 400. The pore water in the soil medium 400 seeps outward under the action of pressure and is discharged into the sand water guide belt 240 after passing through the geotextile 230 and the holes on the inner wall 1210 of the side wall. The particles in the soil medium 400 cannot enter the sand guide belt 240 due to the obstruction of the geotextile 230, and the pore water is discharged through the second drainage port 005.

[0059] The soil trough 100 is provided with a lateral filter layer 300 and / or a bottom filter layer 300 to accelerate the consolidation speed of the soil and save experimental time.

[0060] In an optional solution of the present embodiment, a pore pressure sensor 600 is provided on the side wall 1200 of the soil trench 100. Furthermore, a plurality of pore pressure sensors 600 are provided on the side wall 1200 along the longitudinal direction to monitor the distribution and changes of excess pore water pressure at different depths during the consolidation process.

[0061] In an optional solution of the present embodiment, a scale 900 is provided on the side wall 1200 of the soil trough 100, and the compression state of the clay soil can be monitored through an observation device.

[0062] In an optional solution of this embodiment, a glass observation window 700 is provided on the side wall 1200 of the soil trough 100 and cannot be provided on the same side wall 1200 as the lateral filter layer 300. The glass observation window 700 can observe changes in the vertical section of the soil during the consolidation process.

[0063] In the optional scheme of this embodiment, a vacuum consolidation device 800 is also included. The vacuum consolidation device 800 includes a negative pressure pump 810, and the negative pressure pump 810 is connected to the first drain port 001 and / or the second drain port 005 through the drainage conduit 1300. Wherein, in the case where the soil trough 100 is provided with both the first drain port 001 and the second drain port 005, the negative pressure pump 810 is connected to the first drain port 001 through the first drainage conduit 1310, and the negative pressure pump 810 is connected to the second drain port 005 through the second drainage conduit 1320, and the first drainage conduit 1310 and the second drainage conduit 1320 are connected in parallel. Further, a pressure gauge 820 and a valve 830 are provided on the drainage conduit 1300. Further, the vacuum consolidation device 800 is also provided with a pressure servo control system 840, and the pressure servo control system 840 is respectively connected to the negative pressure pump 810, the pressure gauge 820 and the valve 830, so that the upper and lower drainage surfaces can be negatively loaded according to the predetermined pressure.

[0064] In the optional solution of this embodiment, please refer to Figure 5 A vertical partition plate 1000 is arranged in the soil trough 100, and the partition plate 1000 divides the soil trough 100 into mutually isolated separation zones 004. An inclined top water filter layer 200 is arranged in the separation zone 004, and the top water filter layer 200 and the inner wall of the separation zone 004 form a closed space for accommodating the soil medium 400; an injection port 002 and a first drainage port 001 are arranged on the top water filter layer 200, and a constraint mechanism 500 is connected above the top water filter layer 200, and the constraint mechanism 500 is configured to drive the top water filter layer 200 to only undergo vertical translational displacement. Each separation area 004 is equivalent to a small soil trough 100. Counterweights can be piled on the top of the filter layer 200 of each separation area 004, or the first drainage outlet 001 of each separation area 004 is connected to the vacuum consolidation device 800 through different drainage ducts 1300. Each separation area 004 is independent of each other and does not affect each other, and can be used to compare and observe the formation process of slope seabeds with different consolidation degrees.

[0065] The experimental simulation device for the slope seabed provided in this embodiment can be applied to both the vacuum consolidation method and the heap loading consolidation method. The heap loading consolidation method has a small loading amount and low requirements for test equipment, and is suitable for the consolidation of soils with relatively strong drainage performance; the vacuum consolidation method has a large loading amount, but requires equipment such as a negative pressure pump 810, and is suitable for the consolidation of soils with relatively strong viscosity. Specifically:

[0066] When the vacuum consolidation method is adopted, the negative pressure pump 810 and the valve 830 are turned on to maintain the reading of the pressure gauge 820 at the specified pressure. When the negative pressure pump is started, the sand water guide belt 240 can evenly transfer the negative pore water pressure to the upper surface of the soil medium 400. The pore water in the soil medium 400 seeps upward or downward under the action of pressure and is discharged into the sand water guide belt 240 through the geotextile 230. The particles in the soil medium 400 cannot enter the sand water guide belt 240 due to the obstruction of the geotextile 230. Because the sealing cloth 220 is sealed and connected to the inner wall of the soil trough 100 to form a closed space, the pore water can only be discharged through the first drainage port 001 on the surface of the sealing cloth 220 or the second drainage port 005 at the bottom of the soil trough 100. During the pore water discharge process, when the soil medium 400 undergoes consolidation and settlement, the top water filter layer 200, which is set to be inclined, can only undergo vertical translational displacement under the action of the constraint mechanism 500. Under the pressure of the top water filter layer 200, the soil can maintain a fixed slope, and under the action of the porous steel plate 210, the upper surface of the soil remains flat during the consolidation process. By controlling the negative pressure or the pressurization time, a slope seabed with different consolidation degrees can be obtained;

[0067] When the loading consolidation method is adopted, counterweights are evenly piled on top of the top water filter layer 200, and the consolidation pressure is controlled by the weight of the weights. The sand water guide belt 240 can evenly transfer the pressure to the upper surface of the soil medium 400. The pore water in the soil medium 400 seeps upward or downward under the action of pressure and is discharged into the sand water guide belt 240 through the geotextile 230. The particles in the soil medium 400 cannot enter the sand water guide belt 240 due to the obstruction of the geotextile 230. Because the sealing cloth 220 is sealed and connected to the inner wall of the soil trough 100 to form a closed space, the pore water can only be discharged through the first drainage port 001 on the surface of the sealing cloth 220 or the second drainage port 005 at the bottom of the soil trough 100. During the pore water discharge process, when the soil medium 400 undergoes consolidation and settlement, the top water filter layer 200, which is set to be inclined, can only undergo vertical translational displacement under the action of the constraint mechanism 500. Under the pressure of the top water filter layer 200, the soil can maintain a fixed slope, and under the action of the porous steel plate 210, the upper surface of the soil remains flat during the consolidation process. By controlling the loading amount and loading time of the counterweight on the top water filter layer 200, a slope seabed with different consolidation degrees can be obtained.

[0068] Embodiment 2

[0069] This embodiment provides a method for preparing a simulated slope seabed using the above device. Specifically, the method comprises the following steps:

[0070] S1: a lateral filter layer 300 is provided, a geotextile 230 is laid on the inner side of the side wall inner wall 1210, a sand water guide belt 240 is provided between the side wall inner wall 1210 and the side wall outer wall 1220, and a second drainage outlet 005 is provided at the bottom of the side wall 1200;

[0071] S2. Setting a bottom filter layer 300, laying a sand water guide belt 240 and a geotextile 230 on the bottom plate 1100 in sequence to form a filter layer 300, wherein the height of the sand water guide belt 240 should ensure that the second drainage outlet 005 at the bottom is completely buried, so that the pore water flowing out of the bottom filter layer 300 can be discharged through the second drainage outlet 005;

[0072] S3, setting a top water filter layer 200, laying a geotextile 230, a porous steel plate 210, a sand water guide belt 240 and a sealing cloth 220 in sequence to form a top water filter layer 200, wherein the sealing cloth 220 is sealed at the connection with the inner wall of the soil trough 100, and the first drainage port 001 on the sealing cloth 220 is directly exposed above the soil trough 100;

[0073] S4. Install the restraint mechanism 510, connect the restraint frame 510 of the restraint mechanism 510 to the porous steel plate 210, and support the mounting frame 530 of the restraint mechanism 510 on the top of the side wall 1200 of the soil trough 100.

[0074] S5, pumping the prepared soil medium 400 into the soil tank 100 through the injection port 002, wherein the soil medium 400 is selected to be muddy saturated clay soil, and the overflow valve 003 is kept open during the injection process. When the overflow valve 003 starts to bubble, the injection is stopped, and the overflow valve 003 and the injection port 002 are closed;

[0075] S61, when the vacuum consolidation method is used, the first drain port 001 and the second drain port 005 are connected to the negative pressure pump 810, the negative pressure pump 810 and the valve 830 are turned on, the vacuum consolidation is started, and the soil with different consolidation degrees is obtained by adjusting the pressurization time and negative pressure value;

[0076] S62. When the pile loading consolidation method is adopted, weights are evenly piled above the top water filter layer 200, and the first drain outlet 001 is directly exposed in the water tank. The pile loading consolidation begins, and soil with different consolidation degrees is obtained by controlling the loading amount and loading time of the weights.

[0077] Combining the first and second embodiments, this embodiment can achieve the following technical effects:

[0078] 1. The structure of the present invention is ingenious and easy to install;

[0079] 2. The present invention can simulate the slope seabed formed by natural sedimentation;

[0080] 3. The present invention can obtain slope seabeds with different slopes or different consolidation degrees;

[0081] 4. Compared with the traditional method, the present invention greatly improves the consolidation speed and saves experimental time;

[0082] 5. The present invention can be applied to both vacuum consolidation method and pile loading consolidation method, and thus can be applied to the consolidation of different types of soils.

Claims

1. An experimental simulation device for a sloped seabed, characterized in that: The simulation device comprises a soil trough (100), wherein an inclined rigid top water filter layer (200) is arranged in the soil trough (100), wherein the top water filter layer (200) and the inner wall of the soil trough (100) form a closed space for accommodating a soil medium (400); an injection port (002) and a first drainage port (001) are arranged on the top water filter layer (200), and a constraint mechanism (500) is connected above the top water filter layer (200), wherein the constraint mechanism (500) is configured to drive the top water filter layer (200) to only undergo a vertical translational displacement.

2. The experimental simulation device for the sloped seabed according to claim 1, characterized in that: The restraint mechanism (500) comprises a restraint frame (510), wherein the restraint frame (510) comprises a horizontally arranged restraint frame cross bar (511) and a first restraint frame longitudinal bar (512) and a second restraint frame longitudinal bar (513) of unequal lengths arranged at both ends of the restraint frame cross bar (511), wherein the lower ends of the first restraint frame longitudinal bar (512) and the second restraint frame longitudinal bar (513) are connected to the top water filtering layer (200).

3. The experimental simulation device for the sloped seabed according to claim 2, characterized in that: The restraining mechanism (500) further comprises a mounting frame (530), wherein the mounting frame (530) comprises a horizontally arranged mounting frame cross bar (531) and two mounting frame longitudinal bars (532) of equal length arranged at both ends of the mounting frame cross bar (531), the mounting frame cross bar (531) being perpendicular to the mounting frame longitudinal bars (532), and the bottom ends of the mounting frame longitudinal bars (532) being connected to the top of the side wall (1200) of the soil trough (100).

4. The experimental simulation device for the sloped seabed according to claim 3, characterized in that: The restraining mechanism (500) further comprises a connecting member (520), wherein the connecting member (520) comprises two connecting rods (521) which are cross-arranged and rotatably connected, and the two ends of the connecting rods (521) are respectively hinged to the restraining frame cross bar (511) and the mounting frame cross bar (531).

5. The experimental simulation device for the sloped seabed according to claim 1, characterized in that: The top water filter layer (200) comprises a geotextile (230) laid on top of the soil medium (400), a sand water guide belt (240) laid on top of the geotextile (230), a porous steel plate (210) arranged in the sand water guide belt (240), and a sealing cloth (220) laid on top of the sand water guide belt (240), wherein a reinforcing rib (211) is arranged above the porous steel plate (210), and the porous steel plate (210) is connected to the restraining mechanism (500).

6. The experimental simulation device for the sloped seabed according to claim 1, characterized in that: A filter layer (300) is provided on the side and / or the bottom of the soil trough (100), and the filter layer (300) is connected to the second drainage port (005).

7. The experimental simulation device for the sloped seabed according to claim 1, characterized in that: The side wall (1200) of the soil trough (100) is provided with a pore pressure sensor (600) and / or a scale (900) and / or a glass observation window (700).

8. The experimental simulation device for the sloped seabed according to claim 6, characterized in that: It also includes a vacuum consolidation device (800), wherein the vacuum consolidation device (800) is connected to the first drain port (001) and / or the second drain port (005) via a drainage conduit (1300).

9. The experimental simulation device for the sloped seabed according to claim 1, characterized in that: A vertical partition plate (1000) is arranged in the soil trough (100), and the partition plate (1000) divides the soil trough (100) into separate areas (004) that are isolated from each other.

10. A method for preparing a simulated slope seabed using the device according to any one of claims 1 to 9, comprising the following steps: S1: a lateral filter layer (300) is provided, a geotextile (230) is laid on the inner side of the side wall inner wall (1210), a sand water guide belt (240) is provided between the side wall inner wall (1210) and the side wall outer wall (1220), and a second drainage outlet (005) is provided at the bottom of the side wall (1200); S2, setting a bottom filter layer (300), laying a sand water guide belt (240) and a geotextile (230) on the bottom plate (1100) in sequence to form a filter layer (300), wherein the height of the sand water guide belt (240) should ensure that the second drainage outlet (005) at the bottom is completely buried, so that the pore water flowing out of the bottom filter layer (300) can be discharged through the second drainage outlet (005); S3, setting a top water filter layer (200), laying a geotextile (230), a porous steel plate (210), a sand water guide belt (240) and a sealing cloth (220) in sequence to form a top water filter layer (200), wherein: The connection between the sealing cloth (220) and the inner wall of the soil trough (100) is sealed, and the first drainage port (001) on the sealing cloth (220) is directly exposed above the soil trough (100); S4, installing the restraining mechanism (500), connecting the restraining frame (510) of the restraining mechanism (500) to the porous steel plate (210), and supporting the mounting frame (530) of the restraining mechanism (500) on the top of the side wall (1200) of the soil trough (100); S5, pumping the prepared soil medium (400) into the soil tank (100) through the injection port (002), wherein the soil medium (400) is selected to be slurry-like saturated clay soil, and the overflow valve (003) is kept open during the injection process. When the overflow valve (003) starts to emit slurry, the injection is stopped, and the overflow valve (003) and the injection port (002) are closed; S61. When the vacuum consolidation method is used, the first drain port (001) and the second drain port (005) are connected to the negative pressure pump (810), the negative pressure pump (810) and the valve (830) are turned on, the vacuum consolidation is started, and the soil with different consolidation degrees is obtained by adjusting the pressurization time and the negative pressure value; S62. When the pile loading consolidation method is adopted, weights are evenly piled above the top drainage layer (200), and the first drainage outlet (001) is directly exposed in the water tank. The pile loading consolidation begins, and soil with different consolidation degrees is obtained by controlling the loading amount and loading time of the weights.

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