Experimental simulation system and method for scour and settlement of platform pile shoe foundation on hard seabed

Abstract

The present invention discloses a system and method for simulating scour and settlement of a platform pile shoe foundation on a hard seabed, including: a data monitoring and acquisition system for monitoring the settlement of the foundation and the local scour phenomenon of the seabed during the scour process, an experimental preparation system, and an experimental flume system; wherein, the experimental preparation system includes a foundation model arrangement system, a seabed filling and leveling system, and an offshore platform foundation model system, and the density of the simulated seabed is controlled based on the seabed filling and leveling system; a hard seabed simulation system is laid inside the experimental flume system, a soil trough hydraulic lift is arranged at the bottom of the hard seabed simulation system, the offshore platform foundation model is arranged at the simulated seabed through the foundation model arrangement system, and the soil trough hydraulic lift is adjusted to simulate different seabed soil thicknesses.

Description

Technical Field

[0001] The present invention belongs to the technical field of ocean surveying, and particularly relates to a system and method for simulating scour and settlement experiments of a platform pile shoe foundation on a hard seabed. Background Art

[0002] In order to meet the increasing demand for energy in economic and social development, humans have started to move towards deep sea for the exploitation of fossil energy such as oil and natural gas. As an important tool for marine resource development, offshore platforms play an indispensable role in aspects such as offshore oil and gas exploration and development, submarine pipeline laying, and marine oil and gas resource exploitation, and are widely used worldwide.

[0003] A jack-up platform is a type of mobile offshore platform, which consists of an upper installation platform, liftable legs, and a platform foundation. During offshore installation operations, the foundation is sunk through the leg lifting to support on the seabed, and the hull is lifted above the sea level to meet the requirements of different water depth conditions for operation and construction accuracy. There are mainly two relatively common foundation forms for jack-up platforms: pile shoe foundation and mat foundation. Generally speaking, for a pile shoe foundation, the legs with pile shoes need to be deeply inserted into the mud to maintain stability and sufficient bearing capacity under the attack of sea waves and surges. The bearing capacity is related to the area of the pile shoe and the penetration depth into the mud.

[0004] During normal operations, if the pile shoe of the foundation penetrates shallowly or does not fully penetrate into the mud, the lateral resistance of the pile shoe foundation is basically provided by the frictional force at the bottom of the foundation. When the contact area at its bottom decreases, there is a risk of sliding instability. The marine environment is complex and changeable. Waves and currents not only exert a certain lateral load on marine structures, but also affect the seabed response around their foundations, generating local scour pits, causing certain stability and safety problems. The seawater flow at the pile shoe is strengthened or vortices appear, which will all enhance the movement of sediment, thus triggering the scour of sediment at the pile leg insertion. If the scour occurs below the bottom surface of the pile shoe, it may cause the sinking of single piles or group piles of the drilling platform, posing a great potential safety hazard.

[0005] On the coastlines of Liaodong, northern Hebei, northern Shandong, eastern Shandong, southern Shandong, northern Jiangsu, eastern Zhejiang, etc. in China, silty sediment is scattered. The port engineering of these coasts involves a large number of sediment problems. In previous projects and research, the main focus was on the scour of platform foundations on sandy seabeds, while the scour of silty and clay seabeds is more complex, which has important engineering significance for the development of local scour of offshore platform foundations on silty seabeds. Conducting physical model experiments on the local scour of offshore platform foundations in a large wave-current flume is one of the important methods to study the scour mechanism. The traditional measurement methods for the local scour of offshore platform foundations mainly include non-contact measurement means such as ultrasonic sensors, laser rangefinders, and topographic image processing. The above non-contact traditional measurement methods are suitable for use on sandy seabeds with low water turbidity.

[0006] Due to the layout form of the offshore platform foundation may cause a certain degree of occlusion to the terrain, there will be certain problems with the traditional non-contact measurement method, and it is impossible to carry out measurements under complex layout forms, the leveling and compaction of the seabed, the scour monitoring during the experiment, the topographic changes before and after the experiment, etc. Summary of the Invention

[0007] To solve the above technical problems, the present invention proposes a simulation system for the scour and settlement experiment of the platform pile shoe foundation on a hard seabed to solve the problems existing in the above prior art.

[0008] To achieve the above object, the present invention provides a simulation system for the scour and settlement experiment of the platform pile shoe foundation on a hard seabed, including:

[0009] A data monitoring and acquisition system, an experimental preparation system, and an experimental flume system for monitoring the foundation settlement and local scour phenomenon of the seabed during the scour process;

[0010] Among them, the experimental preparation system includes a foundation model layout system, a seabed filling and leveling system, and an offshore platform foundation model system, and controls the simulated seabed density based on the seabed filling and leveling system;

[0011] The inside of the experimental flume system is paved with a hard seabed simulation system, and a soil flume hydraulic lift is arranged at the bottom of the hard seabed simulation system. The offshore platform foundation model is arranged at the simulated seabed through the foundation model layout system, and the soil flume hydraulic lift is adjusted to simulate different seabed soil thicknesses.

[0012] Preferably, the data monitoring and acquisition system includes: a capacitive scour measurement system, a foundation settlement monitoring system, a seabed pore pressure monitoring system, a topographic scanning system, and a data acquisition and processing system.

[0013] Preferably, the topographic scanning system includes: a topographic scanner and a high-definition underwater camera;

[0014] The experimental scoured terrain is scanned by a terrain scanner, and the local scouring condition during the experiment is photographed by a high-definition underwater camera.

[0015] Preferably, the foundation settlement monitoring system includes: a laser rangefinder and a high-definition camera, and the sinking state of the model is monitored in real time by the laser rangefinder and the high-definition camera.

[0016] Preferably, the foundation model layout system includes longitudinal guide rails, transverse steel beams, longitudinal short steel beams and fixed steel clips;

[0017] Among them, there are two mutually parallel longitudinal guide rails, and the two longitudinal guide rails are respectively arranged on both sides of the top surface of the experimental water tank; two transverse steel beams are installed between the two longitudinal guide rails, and the longitudinal short steel beams are fixed between the two transverse steel beams by fixed steel clips.

[0018] Preferably, the seabed filling and leveling system includes: longitudinal guide rail sliders, transverse guide rails, stepping motors and transverse guide rail sliders;

[0019] Among them, two longitudinal guide rail sliders are respectively arranged above the two longitudinal guide rails, three transverse guide rails are installed in parallel between the two longitudinal guide rails, two transverse guide rail sliders are respectively installed on the transverse guide rails, and the transverse guide rail sliders are driven to move by a stepping motor.

[0020] Preferably, it further includes a vibration motor and a wave maker;

[0021] The soil material in the seabed model is shaken evenly by the vibration motor, the seabed model is leveled by controlling the scraping floor and the ramming device through the stepping motor, and a pre-pressure is applied to the seabed model by the wave maker to achieve the simulated density of the seabed.

[0022] To achieve the above technical objectives, the present invention also provides a simulation method for scouring and settlement experiments of a platform pile shoe foundation on a hard seabed, which is characterized in that, based on the simulation system for scouring and settlement experiments of a platform pile shoe foundation on a hard seabed, the method includes the following steps:

[0023] Build the framework of the experimental water tank system;

[0024] Install the data monitoring and acquisition system and the experimental preparation system on the framework of the experimental water tank system respectively;

[0025] Based on the hard seabed simulation system of the experimental water tank system, simulate the hard seabed;

[0026] Control the density of the hard seabed based on the seabed filling and leveling system of the experimental preparation system;

[0027] Based on the basic model layout system of the experimental preparation system, the offshore platform basic model is arranged at the simulated seabed, and the soil tank hydraulic lift at the bottom of the rigid seabed simulation system is adjusted to simulate different seabed soil thicknesses.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] The present invention provides a simulation system for scour and settlement experiments of a platform pile shoe foundation on a rigid seabed, including: a data monitoring and acquisition system for monitoring foundation settlement and local scour phenomena of the seabed during the scour process, an experimental preparation system, and an experimental water tank system; wherein, the experimental preparation system includes a basic model layout system, a seabed filling and leveling system, and an offshore platform basic model system, and the density of the simulated seabed is controlled based on the seabed filling and leveling system; a rigid seabed simulation system is laid inside the experimental water tank system, and a soil tank hydraulic lift is arranged at the bottom of the rigid seabed simulation system. The offshore platform basic model is arranged at the simulated seabed through the basic model layout system, and the soil tank hydraulic lift is adjusted to simulate different seabed soil thicknesses.

[0030] The present invention comprehensively applies the seabed filling and leveling system and innovatively designs the rigid seabed simulation system. The density of the simulated seabed can be controlled through the combined action of pre-pressure, a ground ramming machine, and a soil tank vibrator, solving the pain point of low repeatability of traditional experiments. The present invention designs the rigid seabed simulation system, which can monitor the pore pressure changes at different depths of the seabed soil during the scour process; through the adjustment of the bottom hydraulic lift, different thicknesses of the seabed can be simulated. The present invention can realize the monitoring of foundation settlement and local scour of the seabed during the scour process; and apply the three-dimensional laser scanning technology to reproduce the local scour landform of the seabed with high precision, full automation, and in real scene; comprehensively investigate the scour pit contour, the maximum depth of the ultimate equilibrium of the scour pit, the maximum width of the ultimate equilibrium of the scour pit, etc.

[0031] The present invention solves the problems such as the measurement problem under complex layout forms that cannot be carried out by conventional means, the leveling and compaction problems of the seabed, the scour monitoring during the experiment, and the topographic changes before and after the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0033] Figure 1 It is a schematic diagram of the experimental water tank and its partial structure of an embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of the platform basic model structure of an embodiment of the present invention;

[0035] Figure 3Schematic diagram of the leveling rammed earth component structure according to an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of the soil filling component structure according to an embodiment of the present invention;

[0037] Figure 5 Schematic diagram of the hard seabed simulation system according to an embodiment of the present invention;

[0038] Among them, 3. Experimental flume system; 111. Capacitive erosion sensor; 112. Variable damper; 113. Sensor power supply; 122. High-definition camera, 131. Positioning steel rod; 141. Terrain scanner; 142. High-definition underwater camera; 151. Display; 152. Control host; 23. Offshore platform foundation model system; 211. Longitudinal guide rail; 212. Transverse steel beam; 213. Longitudinal short steel beam; 215. Transverse lead screw; 216. Lead screw slider; 217. Vertical rod; 221. Longitudinal guide rail slider; 222. Transverse guide rail; 223. Stepper motor; 224. Transverse guide rail slider; 225. Soil filling component; 227. First power supply; 2251. Soil sample frame; 2252. Pushing screw; 2253. Coarse soil sample grille; 2261. Transverse scraping floor; 2262. Longitudinal scraping floor; 2263. Leveler; 231. Cylindrical pile leg; 232. Top load-bearing platform; 2321. Vibration excitation device; 233. Foundation pile shoe; 234. Scale; 32. Hard seabed simulation system; 321. Soil trough hydraulic lift; 322. Vibration motor; 331. Ultrasonic flowmeter; 332. Capacitive wave height meter. Detailed implementation manners

[0039] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0040] It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0041] Embodiment 1

[0042] As Figure 1 shown, in this embodiment, a hard seabed upper platform pile shoe foundation erosion and settlement experimental simulation system is provided, including: a data monitoring and acquisition system, an experimental preparation system, and an experimental flume system 3;

[0043] The data monitoring and acquisition system includes a capacitive erosion measurement system, a foundation settlement monitoring system, a seabed pore pressure monitoring system, a terrain scanning system, and a data acquisition and processing system.

[0044] Specifically, as Figure 2 shown, the capacitive scour measurement system includes a capacitive scour sensor 111, a variable damper 112, and a sensor power supply 113; the capacitive scour sensor 111 is assembled outside the basic model; the capacitive scour sensor 111 is electrically connected to the data acquisition system 15 through the variable damper 112, and the sensor power supply 113 is used to supply power to the capacitive scour sensor 111.

[0045] In this embodiment, the capacitive scour sensor 111 is powered by a 12V sensor power supply 113. The capacitive scour sensor 111 is inserted into the seabed to form a microcircuit with the seabed. As the scour develops, the depth-time history change of the scour pit is obtained through the change in capacitance.

[0046] The foundation settlement monitoring system includes a cylindrical pile leg, with two coatings having large color differences applied at intervals along the direction perpendicular to the scale; and high-definition video cameras 122 are symmetrically arranged around the basic model along the incoming wave direction of the experimental water tank to photograph the scale. The laser displacement sensor is used to interact with the data acquisition and processing system to realize the foundation settlement monitoring during the experiment.

[0047] The seabed pore pressure monitoring system includes a seabed soil tank, a positioning steel rod 131, and a pore pressure sensor. The positioning steel rod 131 is perpendicular to the bottom plate of the soil tank, and a steel wire extends outward at a certain distance at intervals, and a pore pressure sensor is arranged here. The pore pressure sensor is connected to the data acquisition and processing system.

[0048] The terrain scanning system includes a terrain scanner 141 and a high-definition underwater camera 142. The terrain scanner 141 and the high-definition underwater camera 142 are hoisted at the bottom of the vertical rod 217. The three-dimensional laser scanner can directly obtain high-density and high-precision point cloud data of the terrain surface. By summarizing and processing the point cloud data, a high-precision and high-resolution digital terrain model can be obtained. Before and after the experiment, the scour pit area is captured and scanned to obtain the local scour landform, and the three-dimensional modeling image of the local scour of the foundation is obtained through the image processing program using the data acquisition and processing system.

[0049] The data acquisition and processing system includes a display 151 and a control host 152; the control host 152 is electrically connected to the display 151, and the control host is used to complete data sorting and information interaction.

[0050] The experimental preparation system includes a basic model layout system, a seabed filling and leveling system, and an offshore platform basic model system 23.

[0051] Specifically, the basic model layout system includes: longitudinal guide rails 211, transverse steel beams 212, longitudinal short steel beams 213, and fixed steel clips 214; there are two mutually parallel longitudinal guide rails 211, and the two longitudinal guide rails 211 are respectively arranged on both sides of the top surface of the experimental water tank 3; two transverse steel beams 212 are installed between the two longitudinal guide rails 211; the two transverse steel beams 212 are fixed by fixed steel clips 214, and the longitudinal short steel beam 213 is fixedly installed with a circular ring bearing to restrain the cylindrical pile leg 231. Additionally, several transverse lead screws 215 and lead screw sliders 216 are provided between the two longitudinal guide rails 211; a vertical rod 217 is installed on each lead screw slider 216; a hydrological data collection device such as an ultrasonic current meter 331 and a capacitive wave height meter 332 is installed at the bottom of the vertical rod 217 to monitor the hydrology before and after the foundation.

[0052] As Figure 3 shown, the seabed filling and leveling system includes longitudinal guide rail sliders 221, transverse guide rails 222, stepping motors 223, and transverse guide rail sliders 224; there are two mutually parallel longitudinal guide rail sliders 221 provided on the longitudinal guide rails 211, which are respectively arranged on both sides of the top surface of the experimental water tank 3; relying on the longitudinal guide rail sliders 221, three transverse guide rails 222 are installed in parallel between the two longitudinal guide rails 211; two transverse guide rail sliders 224 are respectively installed on the transverse guide rails 222; anchor bolts are reserved above the transverse guide rail sliders 224 for fixing the filling component 225 and the leveling ramming component.

[0053] Among them, as Figure 4 shown, the filling component 225 includes a soil sample frame 2251, a feeding screw 2252, a coarse soil sample grid 2253, a motor, and a fixed anchor bolt platform; the motor is electrically connected to the first power supply 227. In this embodiment, the filling component 225 and the grader 2263 share one guide rail. During the experiment, first use the filling component 225 to fill the soil into the soil tank of the hard seabed simulation system 32, start the vibration motor 322 to shake the soil in the soil tank to ensure uniform filling, and then disassemble and replace the grader 2263 for ramming work during the subsequent leveling and ramming work.

[0054] Among them, the leveling rammed earth component includes a transverse scraping floor 2261, a longitudinal scraping floor 2262, and a land-leveler 2263; the land-leveler 2263 is installed at the bottom of the vertical rod 217. In this embodiment, the transverse scraping floor 2261 is used for leveling around the foundation, and the longitudinal scraping floor 2262 is used for leveling the entire simulated seabed within the rigid seabed simulation system 32. Further, there is a major problem in the current scour experiments, that is, after each group of experiments, the water needs to be drained and the seabed needs to be leveled manually. Firstly, there are large experimental errors and resource waste in doing so, and it is also very difficult to ensure that the flatness and density of the seabed are the same each time, so it is very difficult to ensure the repeatability of the experiments. In this embodiment, the soil tank hydraulic elevator 321 is used to lift the seabed to expose the soil tank above the water surface, and the transverse scraping floor 2261 and the longitudinal scraping floor 2262 driven by the stepping motor 223 are opened to perform large-scale leveling of the seabed and leveling near the foundation model. Then, the land-leveler 2263 is used in combination with the self-propelled ramming plate to compact the leveled simulated seabed, ensuring that the density of each group of experiments is basically consistent.

[0055] A capacitive scour measurement system and a foundation settlement monitoring system are installed in the offshore platform foundation model system 23; they are used to detect the local scour depth and sinking state of the offshore platform foundation model system 23, and are both electrically connected to the data acquisition system.

[0056] As Figure 2 shown, the offshore platform foundation model system 23 includes cylindrical pile legs 231, a top load-bearing platform 232, and foundation pile shoes 233. It is hoisted and inserted into the rigid seabed simulation system 32 through the foundation model layout system, and the cylindrical pile legs 231, the top load-bearing platform 232, and the foundation pile shoes 233 are bolted together and perpendicular to the experimental simulated seabed. The top load-bearing platform 232 is used to assemble counterweights and install a vibration excitation device 2321 to simulate the complex working conditions of the offshore platform. In this embodiment, the cylindrical pile legs 231 are made of stainless steel, the top load-bearing platform uses cast iron counterweights, and a laboratory overhead crane is used for hoisting.

[0057] A scale 234 is adhered to the top of the cylindrical pile leg 231 along the axial direction; the foundation settlement monitoring system is arranged on each of the cylindrical pile legs 231. In this embodiment, a high-definition video recorder 121 is used to record videos of the scale, and a laser displacement sensor 122 is used to monitor the foundation settlement condition; the capacitive scour sensor system is arranged on each of the foundation pile shoes.

[0058] The experimental water tank system 3 includes a marine environment simulation system, a rigid seabed simulation system 32, and a hydrological monitoring system.

[0059] The marine environment simulation system includes a wave maker and a current maker. The wave maker and the current maker are installed at the very front end of the wave-current flume. Waves are formed by the movement of the wave-pushing plate, and ocean currents are formed by the current pump. The wave-making and current-making elements are controlled by the main control host. A dissipation net is provided at the rear side of the wave maker to prevent water from splashing out during wave-making; a dissipation slope is provided at the end of the wave-current flume to eliminate the waves reaching the flume boundary and reduce the influence of the wave waveform caused by reflection. The two sides of the flume are glass walls with height scales, which are convenient for experimental observation and recording.

[0060] As Figure 5 shown, the rigid seabed simulation system 32 includes a soil trough hydraulic lift 321, a vibration motor 322, and a positioning steel rod 131. The soil trough hydraulic lift 321 is used to lift the soil trough for experimental preparation and can adjust the height to simulate seabeds of different thicknesses. The vibration motor 322 mainly exerts a lateral action during the process of filling and tamping the soil to prepare a dense seabed soil mass. The positioning steel rod 131 is installed at the bottom of the soil trough, and a pore pressure sensor is tied.

[0061] The hydrological monitoring system includes an ultrasonic current meter 331 and a capacitive wave height meter 332, which are mainly used to calibrate and monitor the wave-making and current-making in the experimental flume, and are arranged at multiple points before and after the basic model along the main wave-making direction.

[0062] In this embodiment, a rigid seabed simulation system 32 is laid in the experimental flume system 3; the offshore platform foundation model system 23 is arranged in the rigid seabed simulation system 32 through the foundation model layout system installed on the top in the rigid seabed simulation system 32; a seabed pore pressure monitoring system is installed in the soil trough to hold the simulated seabed and monitor the pore pressure response. In this embodiment, pore pressure sensors are set at the same positions in front of, behind, and on the sides of the foundation at different depths. The pore pressure sensors are used to hold the simulated seabed and monitor the pore pressure response at different depths in the seabed.

[0063] This embodiment proposes a detection method for the local scour topography of the offshore platform foundation using an underwater high-definition camera, a terrain scanner, and capacitive scour measurement, for detecting the scour pit contour, the maximum depth of the ultimate equilibrium of the scour pit, and the maximum width of the ultimate equilibrium of the scour pit in the scour experiment; the laying and leveling of the simulated seabed are facilitated through the seabed filling and leveling system, solving the pain point of low repeatability of traditional experiments.

[0064] Embodiment Two

[0065] This embodiment provides a method for simulating the scour and settlement experiment of the platform pile shoe foundation on a rigid seabed. Based on the rigid seabed platform pile shoe foundation scour and settlement experiment simulation system described in Embodiment One, the method includes the following steps:

[0066] Build the framework of the experimental flume system 3;

[0067] Install the data monitoring and acquisition system and the experimental preparation system on the frame of the experimental flume system 3 respectively;

[0068] Based on the hard seabed simulation system 32 of the experimental flume system 3, simulate the hard seabed;

[0069] Based on the seabed filling and leveling system of the experimental preparation system, control the compactness of the hard seabed;

[0070] Based on the basic model layout system of the experimental preparation system, arrange the offshore platform basic model system 23 at the simulated seabed, and adjust the soil tank hydraulic lift 321 at the bottom of the hard seabed simulation system 32 to simulate different seabed soil thicknesses.

[0071] In this embodiment, the specific implementation steps include:

[0072] Step 1: Install the longitudinal guide rail 211 and the superstructure. First, install devices such as the longitudinal guide rail 211, the transverse guide rail 222, the screw slider 216, the transverse lead screw 215, and the stepping motor 223 at the top ends of both sides of the experimental flume 3 to complete the construction of the main frame of the auxiliary system of the experimental flume system 3; install the seabed filling and leveling system, and connect the transverse scraping floor 2261, the longitudinal scraping floor 2262, and the leveling device 2263 to the screw slider 216 of the outer guide rail through the vertical rod 217. Assemble the hard seabed simulation system 32, assemble the positioning steel rod 131, install the pore pressure sensor and connect it to the control host. Lift and install the hard seabed simulation system 32 into the experimental flume 3.

[0073] Step 2: Fill the hard seabed simulation system 32 with soil. Fill the hard seabed simulation system 322 with water, assemble the soil filling component 225 and install it on the transverse guide rail slider 224. Use the overhead crane to lift the experimental soil sample and feed it into the soil sample frame 2251. Start the feeding screw 2252 and the stepping motor 223 to evenly put the soil material into the soil tank. Turn on the vibration motor 322 to shake the soil material in the soil tank evenly. Close the soil filling component 225, and control the scraping floor and the leveling device through the stepping motor 223 to level and compact the seabed. Use the wave maker to generate waves to apply pre-pressure to the seabed model and make the seabed soil saturated and consolidated for 24 hours to ensure that the model soil has the same compactness as the in-situ soil;

[0074] Step 3: Installation of the offshore platform foundation model system 23. Assemble the capacitive scour sensor 111 and connect the sensor power supply 113. The output signal of the capacitive scour sensor 111 is connected to the control host 152 via the variable damper 112. Assemble the cylindrical pile leg 231, the counterweight top load-bearing platform 232, and the foundation pile shoe 233 and hoist them into the experimental water tank system 3. Fix a transverse steel beam 212 in advance and fix the longitudinal short steel beam 213 at the predetermined position. Use the overhead crane to lift the offshore platform foundation model system 23 and control the relevant longitudinal sliding block 221 to slide to the predetermined scale through the stepping motor 223, slowly lower it and install the foundation model 23, install and fix another transverse steel beam 212, and fix the position of the foundation model, as Figure 1 shown. Use the overhead crane to hoist the counterweight to ensure uniform counterweight of the foundation model and stable center of gravity.

[0075] Step 4: Installation of the hydrological data acquisition device. In front of the foundation model 23 in the oncoming flow direction, arrange the ultrasonic current meter 331 and the capacitive wave height meter 332 into the water respectively through the vertical rod 217.

[0076] Step 5: Install the terrain scanner 141 and the high-definition underwater camera 142. The high-definition underwater camera 142 and the terrain scanner 141 are driven by the stepping motor 223 to drive the screw slider 216 and the transverse lead screw 215 to move back and forth, left and right in the water tank, and move vertically through the vertical rod 217. At the same time, connect the relevant image data to the control host 152 via the transmission line;

[0077] Step 6: The installation of the device is completed and the experiment is ready to start. Fill the experimental water tank system 3 with water to the target height, turn on the vibration excitation device 2321 to simulate the working load of the offshore platform. Turn on the wave maker and the current generator to generate the target wave height and period waves and the target flow velocity water flow. Scour phenomena begin to appear in the seabed soil near the foundation model, and the scour pits expand and deepen continuously from the middle to both sides. The scour pits finally reach the equilibrium state and the experiment is completed;

[0078] Step 7: Use the high-definition underwater camera 142 to capture the scour pits in front of and behind the foundation at fixed intervals during the experiment to analyze the expansion speed of the scour pit edge; and receive and record the scour pit depth data of the capacitive scour sensor 111 to analyze and obtain the expansion speed of the scour pit and the change of the scour pit depth with time;

[0079] Step 8: Turn off the switches of the current generator and the wave maker, drain the water until the seabed scour pits are exposed, use the stepping motor 223 to move the front and rear cameras away, control the terrain scanner 141 to perform terrain scanning and sampling to obtain the scanned image with piles. Use the overhead crane to load and unload the counterweight, pull out the offshore platform foundation model system 23, control the terrain scanner 141 to perform terrain scanning and sampling again, and use the control host to generate a three-dimensional scanning model.

[0080] Step Nine: Repeat Steps Two and Eight to conduct the next set of experimental conditions.

[0081] The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A simulation system for scouring and settlement of a pile shoe foundation on a hard seabed, characterized in that: include: Data monitoring and acquisition system, experimental preparation system and experimental flume system for monitoring foundation settlement and local seabed scouring during scouring; The experimental preparation system includes a basic model layout system, a seabed filling and leveling system and an offshore platform basic model system, and the seabed filling and leveling system is used to control the density of the simulated seabed; A hard seabed simulation system is laid inside the experimental water tank system, and a soil tank hydraulic lift is arranged at the bottom of the hard seabed simulation system. The offshore platform foundation model system is arranged at the simulated seabed through the foundation model arrangement system, and the soil tank hydraulic lift is adjusted to simulate different seabed soil thicknesses; The experimental water tank system includes a marine environment simulation system, a hard seabed simulation system, and a hydrological monitoring system. The marine environment simulation system includes a wave maker and a flow maker. The wave maker and the flow maker are installed at the front end of the wave and flow tank. Waves are formed by the movement of the wave pusher, and ocean currents are formed by the flow pump. The wave and flow elements are controlled by the control host. An energy dissipation net is provided on the rear side of the wave maker to prevent water from splashing when making waves. An energy dissipation slope is provided at the tail end of the wave and flow tank to eliminate waves reaching the tank boundary and reduce the impact of wave waveforms caused by reflection. Both sides of the tank are equipped with height The hard seabed simulation system includes a soil tank hydraulic lift, a vibration motor and a positioning steel rod. The soil tank hydraulic lift is used to lift the soil tank for experimental preparation, and the height can be adjusted to simulate seabeds of different thicknesses. The vibration motor mainly exerts lateral force during the filling and tamping process to prepare dense seabed soil. The positioning steel rod is installed at the bottom of the soil tank and the pore pressure sensor is tied. The hydrological monitoring system includes an ultrasonic flow meter and a capacitive wave height meter, which are mainly used to calibrate and monitor the wave and flow generation of the experimental water tank. They are arranged at multiple points in front and behind the basic model along the main wave generation direction. The basic model layout system includes longitudinal guide rails, transverse steel beams, longitudinal short steel beams and fixed steel clamps; Among them, the longitudinal guide rails are provided with two mutually parallel ones, and the two longitudinal guide rails are respectively arranged on both sides of the top surface of the experimental water tank; two transverse steel beams are installed between the two longitudinal guide rails, and the longitudinal short steel beam is fixed between the two transverse steel beams by fixing steel clips; The seabed filling and leveling system comprises: a longitudinal guide rail slider, a transverse guide rail, a stepper motor and a transverse guide rail slider; Among them, two longitudinal guide rail sliders are respectively arranged above the two longitudinal guide rails, three transverse guide rails are installed in parallel between the two longitudinal guide rails, two transverse guide rail sliders are respectively installed on the transverse guide rails, and the transverse guide rail sliders are driven to move by a stepper motor; Anchor bolts are reserved above the transverse guide rail sliders for fixing the filling assembly and the leveling and tamping assembly; the leveling and tamping assembly includes a transverse scraping floor, a longitudinal scraping floor and a leveler. The seabed is lifted by a soil trough hydraulic lift to expose the soil trough to the water surface, and the transverse scraping floor and longitudinal scraping floor driven by the stepper motor are turned on to perform large-scale leveling of the seabed and leveling near the foundation model. After that, the leveler is used in combination with a self-propelled tamping plate to compact the simulated seabed after leveling; The offshore platform foundation model system includes cylindrical pile legs, top load-bearing platform and foundation pile shoes. The piles are hoisted and placed in the hard seabed simulation system through the foundation model layout system, and the cylindrical pile legs, top load-bearing platform and foundation pile shoe anchor bolts are combined and vertical in the experimental simulation seabed. The top load-bearing platform is used to assemble counterweights and install vibration excitation devices to simulate the complex working conditions of the offshore platform. The cylindrical pile legs are made of stainless steel, the top load-bearing platform is made of cast iron counterweights, and is hoisted by a laboratory overhead crane; a scale is adhered to the top of the cylindrical pile legs along the axial direction; the cylindrical pile legs are all arranged with a foundation settlement monitoring system, a high-definition video recorder is used to record the scale video, and a laser displacement sensor is used to monitor the foundation settlement; the foundation pile shoes are all arranged with a capacitive scour sensor system; The soil in the seabed model is shaken evenly by the vibration motor, the scraper and tamper are controlled by the stepper motor to level the seabed model, and the wave maker is used to pre-press the seabed model to achieve the density of the simulated seabed; The data monitoring and acquisition system includes: a capacitive scour measurement system, a foundation settlement monitoring system, a seabed pore pressure monitoring system, a terrain scanning system and a data acquisition and processing system; The capacitive scour measurement system includes a capacitive scour sensor, a variable damper and a sensor power supply; the capacitive scour sensor is mounted on the outside of the basic model; the capacitive scour sensor is electrically connected to the data acquisition system through the variable damper, and the sensor power supply is used to power the capacitive scour sensor; The foundation settlement monitoring system includes: a laser rangefinder and a high-definition camera, which monitor the sinking state of the model in real time. The seabed pore pressure monitoring system includes a seabed soil trough, a positioning steel rod and a pore pressure sensor. The positioning steel rod is perpendicular to the bottom plate of the soil trough, and a steel wire is extended outward at a certain distance. The pore pressure sensor is arranged here, and the pore pressure sensor is connected to the data acquisition and processing system. The seabed pore pressure monitoring system includes a seabed soil trough, a positioning steel rod and a pore pressure sensor. The positioning steel rod is perpendicular to the bottom plate of the soil trough, and a steel wire is extended outward at a certain distance. The pore pressure sensor is arranged thereon, and the pore pressure sensor is connected to the data acquisition and processing system. The data acquisition and processing system includes a display and a control host; the control host is electrically connected to the display, and the control host is used to complete data sorting and information exchange; The terrain scanning system includes: a terrain scanner and a high-definition underwater camera; The experimental scouring terrain was scanned by a terrain scanner, and the local scouring conditions in the experiment were photographed by a high-definition underwater camera.

2. A simulation method for scouring and settlement experiment of a pile shoe foundation on a hard seabed, characterized in that: Based on the scouring and settlement experimental simulation system for the platform pile shoe foundation on the hard seabed according to claim 1, the method comprises the following steps: Build the experimental flume system framework; The data monitoring and acquisition system and the experimental preparation system are respectively installed on the experimental water tank system frame; A hard seabed simulation system based on the experimental flume system simulates a hard seabed; A seabed filling and leveling system based on the experimental preparation system controls the density of the hard seabed; The basic model arrangement system based on the experimental preparation system arranges the offshore platform basic model system at the simulated seabed, and adjusts the soil trough hydraulic lift at the bottom of the hard seabed simulation system to simulate different seabed soil thicknesses.

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