A flexible settlement detection device and test method for underwater subgrade indoor testing

Abstract

A flexible settlement detection device and method for underwater subgrade indoor testing, relating to the field of underwater subgrade settlement detection technology. The method involves determining the embedment position of the settlement plate and the position of the movable slider on the guide rail. During the layered filling of the subgrade, the flexible settlement plate and wire are embedded according to the filling position, and then the guide rail is removed. After the subgrade filling is completed, the wire is pulled out and fixed to the guide rail, completing the device installation. Pre-compaction data is read through the positioning plate, and the guide rail is removed again. After the subgrade is compacted, the guide rail is reinstalled, ensuring the internal wire is vertical, and post-compaction data is read to calculate the compaction settlement. This invention has strong anti-interference capabilities and adapts to complex underwater environments. Simultaneous multi-point detection enables simultaneous recording of settlement at multiple points, enhancing the comprehensiveness and accuracy of subgrade settlement information. It is easy to operate, reusable, and convenient for multiple rounds of indoor testing, especially suitable for large-scale model tests and simulated blasting compaction scenarios with severe disturbances.

Description

Technical Field

[0001] This invention relates to the field of underwater subgrade settlement detection technology, and in particular to an underwater subgrade indoor test flexible settlement detection device and test method. Background Technology

[0002] Underwater foundation settlement detection is a crucial step in ensuring the structural safety of hydraulic engineering projects, submarine pipelines, bridge foundations, and other structures. Due to the complex underwater environment, including turbid water and current disturbances, detection methods must combine traditional measurement techniques with modern sensor technology. Therefore, the most commonly used methods are water thallium measurement and sea-sweeping measurement.

[0003] In indoor settlement detection, commonly used methods include the settlement plate method, laser displacement detection method, and the emerging image processing technology. When simulating underwater rock-filled foundations in indoor experiments, laser displacement sensors are susceptible to light scattering caused by water turbidity, abrupt changes in reflective surfaces due to dynamic rock displacement, and vibration interference. Settlement plates may cause data distortion due to rock collisions, uneven foundation settlement, or fluctuations in pore water pressure. Image recognition technology faces challenges such as underwater light attenuation, obstruction by suspended particles, and complex surface textures of the foundation. Summary of the Invention

[0004] To address the aforementioned problems in existing indoor settlement monitoring methods, this invention proposes a flexible settlement detection device for underwater subgrade indoor testing. By combining a flexible settlement plate with a multi-point layout and water-powered guide wires, it can avoid the influence of wastewater generated by underwater blasting and eliminate settlement detection errors caused by rock collisions, making it suitable for small-scale underwater settlement detection. Another objective of this invention is to provide a method for conducting indoor flexible settlement detection tests on underwater subgrades using this device.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for indoor flexible settlement testing of underwater subgrade includes the following steps:

[0007] Step 1: Determine the thickness of the compacted base bed and fill the model box with sand.

[0008] Step 2: Determine the embedment depth and location of the three flexible settlement plates within the subgrade, and lay them out according to the settlement monitoring points designed for the experiment; simultaneously, determine the vertical positions of the three movable pulleys on the guide rails; one and two pulleys are respectively arranged in the guide grooves on both sides of the guide rails to achieve independent measurement of the three monitoring points at different elevations and to avoid spatial interference between the pulleys and the wires; when adjusting the position of the movable pulleys on the guide rails, ensure that the connecting steel wires led out from the settlement plates can remain vertical through the pulleys during installation, thereby establishing an accurate benchmark for subsequent settlement measurements;

[0009] Step 3: When filling in layers, follow the construction sequence from bottom to top. Start with the lowest-positioned settlement slab. According to the filling position, bury the settlement slab and its connected movable pulley and wire in it. Then loosen the positioning bolts of the movable pulley and slide it out of the guide groove of the guide rail together with the wire. Then remove the guide rail and carry out the filling of the next layer. Repeat this process to bury the middle and top layers of settlement slabs in sequence until the filling is complete.

[0010] Step 4: When the base bed filling is completed, reinstall the guide rail, and pass the iron wires corresponding to the three settlement plates through their respective movable pulleys in turn. Adjust the position of the movable pulleys on the guide rail to ensure that the three iron wires are in a vertical state. Then tighten the positioning bolts to fix the movable pulleys and complete the installation of the device.

[0011] Step 5: After the device is installed and straightened, wait for the water surface to calm down, read the data before tamping through the position of the positioning plate. After the data is read, loosen the positioning bolt of the movable pulley, separate the pulley from the wire, and remove the guide rail.

[0012] Step 6: According to the test plan, set up explosives for blasting and compaction;

[0013] Step 7: After the foundation bed is compacted, wait for the suspended matter in the water to settle, then reinstall the guide rails, ensuring that the internal iron wires are vertical. Observe the position of the positioning plate after it moves with the iron wires, read the data after compaction, and calculate the compaction settlement by the difference between the data before and after compaction.

[0014] An underwater submersible bed indoor test flexible settlement detection device includes a guide rail, a pulley mechanism, and a measuring mechanism. The guide rail has guide grooves cut into both sides for connecting the pulley mechanism. The pulley mechanism includes a movable pulley and a fixed pulley. The movable pulley is fixed in the guide groove by positioning bolts, and its movement and fixation on the guide rail plane are achieved by tightening and loosening the positioning bolts. The movable pulley is connected to a flexible settlement plate via a wire. The other end of the wire is connected to the measuring mechanism via the fixed pulley. The measuring mechanism includes a ruler, a counterweight, and a positioning plate. The counterweight and positioning plate are sequentially connected to the measuring end of the wire. The counterweight ensures the wire is vertical at the measuring end. The ruler is independently fixed, attached to the inner wall of the model box, and does not move with the wire or counterweight. Its scale faces outwards, corresponding to the position of the positioning plate, providing specific values ​​for changes in the position of the positioning plate.

[0015] One of the guide grooves connects two movable pulleys, and the other guide groove connects one movable pulley. This design is intended to achieve simultaneous and independent measurement of three monitoring points at different depths. Placing the three pulleys on both sides of the guide rail effectively prevents the three connected wires from colliding and tangling in the confined space, ensuring the independence of each measuring wire. In terms of the operational sequence, the installation follows a bottom-up principle (bottom layer, then middle layer, then top layer) to accommodate the layered filling construction process.

[0016] The downward-pointing wire is vertical.

[0017] The flexible settlement plate is made of iron sheet with an area between 100cm² and 400cm² and a mass between 200g and 800g, to ensure sufficient stability in the riprap bed and prevent it from being displaced by stones. When the flexible settlement plate is tilted, the point at its center represents the uniform elevation of the settlement plate area.

[0018] The guide rail is a 5mm thick, 76mm high and wide, and 1300mm long I-beam steel, and the guide groove is 10-20mm high and 1100mm long.

[0019] This invention is based on the principle of a flexible settlement plate and a water-cooled wire. The settlement plate changes position as the subgrade settles, causing the connected wire to move vertically. A pulley system transmits this displacement to a guide rail positioning plate. Finally, a ruler is used to read the position difference of the positioning plate before and after compaction, thus obtaining the settlement amount at the corresponding point. This device utilizes the excellent flexibility and stability of the wire, combined with a gravity counterweight to ensure verticality, effectively isolating external interference from the underwater environment such as silt disturbance, rock impacts, and blasting vibrations, thereby achieving accurate and reliable settlement detection.

[0020] This invention boasts strong anti-interference capabilities and adaptability to complex underwater environments. The flexible settlement plate, combined with the water-lift wire and settlement plate design, effectively avoids measurement errors caused by water turbidity, rock collisions, and vibration interference, surpassing traditional methods such as laser displacement sensors. Multi-point synchronous detection enables simultaneous recording of settlement at multiple points, enhancing the comprehensiveness and accuracy of subgrade settlement information. It is easy to operate and reusable; the guide rail and pulley structure standardizes the installation and reading process, and the positioning plate with a ruler facilitates reading. It can be repeatedly assembled, disassembled, and used, facilitating multiple rounds of indoor testing. The structure is simple and low-cost, requiring only ordinary iron wire, steel, and counterweight components for assembly. The process is simple, and the cost is far lower than high-precision electronic measuring equipment, making it particularly suitable for large-scale model testing. It is applicable to simulated violent disturbance scenarios such as blasting and compaction. The device design specifically considers the instantaneous disturbance caused by blasting and sewage interference, ensuring measurement stability and reliability even under severe conditions. Attached Figure Description

[0021] Figure 1 A three-dimensional view of the overall structure of the device of the present invention;

[0022] Figure 2 Front view of the overall structure of the device of the present invention;

[0023] Figure 3 Side view of the overall structure of the device of the present invention;

[0024] Figure 4 Schematic diagram illustrating the application effect of the device of the present invention;

[0025] In the diagram: 1—guide rail; 2—movable pulley; 3—fixed pulley; 4—ruler; 5—counterweight; 6—positioning plate; 7—flexible settling plate; 8—wire; 9—positioning bolt. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the specific embodiments.

[0027] Example 1

[0028] A flexible settlement detection device for indoor testing of underwater subgrade includes a guide rail 1, a pulley mechanism, and a measuring mechanism. The guide rail 1 has guide grooves cut into both sides for connecting the pulley mechanism. The pulley mechanism includes a movable pulley 2 and a fixed pulley 3. The movable pulley 2 is fixed in the guide groove by positioning bolts 9, and its movement and fixation on the plane of the guide rail 1 are achieved by tightening and loosening the positioning bolts 9. The movable pulley 2 is connected to a flexible settlement plate 7 via a wire 8. The other end of the wire 8 is connected to the measuring mechanism via the fixed pulley 3. The measuring mechanism includes a ruler 4, a counterweight 5, and a positioning plate 6. The counterweight 5 and the positioning plate 6 are sequentially connected to the measuring end of the wire 8. The counterweight 5 ensures that the wire 8 at the measuring end is vertically tensioned. The ruler 4 is independently fixed, attached to the inner wall of the model box, and does not move with the wire or counterweight. Its scale faces outwards, corresponding to the position of the positioning plate 6, providing specific values ​​for changes in the position of the positioning plate 6.

[0029] Two movable pulleys 2 are connected in one of the guide grooves, and one movable pulley 2 is connected in the other guide groove.

[0030] The downward-pointing line of the iron wire 8 is vertical.

[0031] The flexible settlement plate 7 is made of iron sheet with an area between 100cm² and 400cm² and a mass between 200g and 800g, to ensure sufficient stability in the riprap bed and prevent it from being displaced by stones. When the flexible settlement plate 7 is tilted, the point at its center represents the uniform elevation of the settlement plate area.

[0032] The guide rail 1 is a 5mm thick, 76mm high and wide, and 1300mm long steel bar, and the guide groove is 10-20mm high and 1100mm long.

[0033] Example 2

[0034] A method for indoor flexible settlement testing of underwater subgrade includes the following steps:

[0035] Step 1: Determine the thickness of the compacted base bed and fill the model box with sand.

[0036] Step 2: Determine the embedment depth and position of the three flexible settlement plates 7 in the subgrade, and lay them out according to the settlement monitoring points designed for the experiment; at the same time, determine the vertical position of the three movable pulleys 2 on the guide rail 1; one and two pulleys are respectively arranged in the guide grooves on both sides of the guide rail 1 to realize independent measurement of the three monitoring points at different elevations and avoid spatial interference between the pulleys and the wire 8; when adjusting the position of the movable pulleys 2 on the guide rail 1, ensure that the connecting steel wires led out from the settlement plates can be kept vertical through the pulleys during installation, thereby establishing an accurate benchmark for subsequent settlement measurement;

[0037] Step 3: When filling in layers, follow the construction sequence from bottom to top. Start with the lowest-positioned settlement plate. According to the filling position, bury the settlement plate and its connected movable pulley 2 and wire 8 in it. Then loosen the positioning bolt 9 of the movable pulley 2 and slide it out of the guide groove of the guide rail 1 together with the wire 8. Then remove the guide rail 1 and carry out the filling of the next layer. Repeat this process to bury the middle and top layer settlement plates in sequence until the filling is complete.

[0038] Step 4: When the base bed filling is completed, reinstall the guide rail 1, and pass the iron wires 8 corresponding to the three settlement plates through their respective movable pulleys 2 in sequence. Adjust the position of the movable pulleys 2 on the guide rail 1 to ensure that the three iron wires 8 are in a vertical state. Then tighten the positioning bolts 9 to fix the movable pulleys 2 and complete the installation of the device.

[0039] Step 5: After the device is installed and straightened, wait for the water surface to calm down, read the data before tamping through the position of the positioning plate 6. After the data is read, loosen the positioning bolt 9 of the movable pulley, separate the pulley from the wire 8, and remove the guide rail 1.

[0040] Step 6: According to the test plan, set up explosives for blasting and compaction;

[0041] Step 7: After the base bed is compacted, wait for the suspended matter in the water to settle, then reinstall the guide rail 1, ensuring that the internal iron wire 8 is vertical, and observe the position of the positioning plate 6 after it moves with the iron wire 8.

[0042] Read the post-compaction data and calculate the compaction settlement by comparing the pre-compaction and post-compaction data.

[0043] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be included within the scope of protection of the present invention.

Claims

1. A method for a flexible settlement test of an underwater foundation bed in a laboratory test, characterized by, Includes the following steps: Step 1: Determine the thickness of the compacted base bed and fill the model box with sand. Step 2: Determine the embedment depth and location of the three flexible settlement plates within the subgrade, and lay them out according to the settlement monitoring points designed for the experiment; simultaneously, determine the vertical positions of the three movable pulleys on the guide rails; one and two pulleys are respectively arranged in the guide grooves on both sides of the guide rails to independently measure the three monitoring points at different elevations and avoid spatial interference between the pulleys and the wires; when adjusting the position of the movable pulleys on the guide rails, ensure that the connecting steel wires led out from the settlement plates can remain vertical through the pulleys during installation, thereby establishing an accurate benchmark for subsequent settlement measurements; Step 3: When filling in layers, follow the construction sequence from bottom to top. Start with the lowest-positioned settlement slab. According to the filling position, bury the settlement slab and its connected movable pulley and wire in it. Then loosen the positioning bolts of the movable pulley and slide it out of the guide groove of the guide rail together with the wire. Then remove the guide rail and carry out the filling of the next layer. Repeat this process to bury the middle and top layers of settlement slabs in sequence until the filling is complete. Step 4: When the base bed filling is completed, reinstall the guide rail, and pass the iron wires corresponding to the three settlement plates through their respective movable pulleys in turn. Adjust the position of the movable pulleys on the guide rail to ensure that the three iron wires are in a vertical state. Then tighten the positioning bolts to fix the movable pulleys and complete the installation of the device. Step 5: After the device is installed and straightened, wait for the water surface to calm down, read the data before tamping through the position of the positioning plate. After the data is read, loosen the positioning bolt of the movable pulley, separate the pulley from the wire, and remove the guide rail. Step 6: According to the test plan, set up explosives for blasting and compaction; Step 7: After the foundation bed is compacted, wait for the suspended matter in the water to settle, then reinstall the guide rails, ensuring that the internal iron wires are vertical. Observe the position of the positioning plate after it moves with the iron wires, read the data after compaction, and calculate the compaction settlement by the difference between the data before and after compaction.

2. An indoor test flexible settlement detection device for underwater foundation bed, characterized in that, The system includes a guide rail, a pulley mechanism, and a measuring mechanism. The guide rail has guide grooves cut into both sides for connecting the pulley mechanism. The pulley mechanism includes a movable pulley and a fixed pulley. The movable pulley is fixed in the guide groove by positioning bolts, and its movement and fixation on the guide rail plane are achieved by tightening and loosening the positioning bolts. The movable pulley is connected to a flexible settling plate via a wire. The other end of the wire is connected to the measuring mechanism via the fixed pulley. The measuring mechanism includes a ruler, a counterweight, and a positioning plate. The counterweight and positioning plate are sequentially connected to the measuring end of the wire. The counterweight ensures the wire is vertical at the measuring end. The ruler is independently fixed, attached to the inner wall of the model box, and does not move with the wire or counterweight. Its scale faces outwards, corresponding to the position of the positioning plate, providing specific values ​​for changes in the position of the positioning plate.

3. The flexible settlement detection device for indoor test of underwater foundation bed according to claim 2, characterized in that, Two movable pulleys are connected in one of the guide grooves, and one movable pulley is connected in the other guide groove. The three pulleys are placed on both sides of the guide rail. In terms of operation sequence, the principle of burying from bottom to top, that is, first the bottom layer, then the middle layer, and finally the top layer, is followed to adapt to the construction process of layered filling.

4. The underwater subgrade indoor test flexible settlement detection device according to claim 2, characterized in that, The downward-pointing wire is vertical.

5. The underwater subgrade indoor test flexible settlement detection device according to claim 2, characterized in that, The flexible settlement plate is an iron sheet with an area of ​​100-400cm² and a mass of 200-800g. When the flexible settlement plate is tilted, the point at its center represents the uniform elevation of the settlement plate area.

6. The underwater subgrade indoor test flexible settlement detection device according to claim 2, characterized in that, The guide rail is a 5mm thick, 76mm high and wide, and 1300mm long I-beam steel, and the guide groove is 10-20mm high and 1100mm long.

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