A measurement system and method of use for laboratory pore pressure response and seabed liquefaction criteria testing

Abstract

This invention relates to a measurement system and method for laboratory-scale experiments on pore pressure response and seabed liquefaction. The measurement system includes a sand-fixing structure to suppress deformation of a model seabed. The sand-fixing structure includes a sand-fixing net, a second slide rail, a third slide rail, and a roller. The first side strip of the sand-fixing net is pulled by the position of the roller, and the second and third side strips slide relative to the second and third slide rails until the formed sand-fixing net covers the model seabed. The formed sand-fixing net is fixed to the second or third slide rail by a fixing clamp. A pore pressure gauge is fixed to the formed sand-fixing net to measure the pore pressure response and liquefaction conditions of the model seabed area covered by the sand-fixing net. This invention is applicable to standard experiments on pore pressure response and seabed liquefaction, and can effectively avoid the influence of seabed deformation on experimental data during the experiment.

Description

Technical Field

[0001] This invention relates to a measurement system and method for laboratory pore pressure response and seabed liquefaction standard experiments, belonging to the field of pore pressure measurement devices, and the pore pressure measurement device is suitable for pore pressure response and seabed liquefaction standard experiments. Background Technology

[0002] In the field of coastal and wave-related research, standard experiments are often required for derivation and verification. Standard experiments usually refer to verification experiments conducted under laboratory conditions. Compared with experiments under natural conditions, they are characterized by the ability to strictly control extraneous variables and manipulate independent variables in a planned manner to observe changes in dependent variables.

[0003] Standard experiments are frequently used in the study of the dynamic response of the seabed under long-period wave loads and soil liquefaction. When studying the dynamic response of the seabed, digital models and physical models can usually be used. For digital model studies, it is only necessary to set the corresponding attribute parameters in the software to ensure that the seabed does not erode or deform during the simulation process. However, it is difficult for physical models to achieve this. In physical models, sand ripples will inevitably appear on the surface of the model seabed after a period of wave load.

[0004] Research on soil liquefaction first clarifies that soil liquefaction refers to the process by which soil, under external cyclic loading, experiences an increase in pore water pressure, a decrease in effective stress between soil particles to zero, and a loss of shear strength, resulting in a liquid state. During liquefaction, sand and water mix to form a mud-like liquid, causing the soil to lose its supporting force, leading to building tilting, ground subsidence, and the rupture or uplift of underground pipelines. However, existing technologies, such as the application with publication number CN212905530 U, which provides a "real-time monitoring device for wave-induced seabed liquefaction depth," cannot effectively control the impact of seabed deformation and therefore fails to meet the requirements of standard laboratory experiments.

[0005] In other words, whether studying the dynamic response of the seabed or soil liquefaction, seabed deformation is not an effective variable for verifying pore pressure response and soil liquefaction. Therefore, the impact of seabed deformation should be minimized as much as possible. However, current experiments have not been able to completely ignore the problems caused by seabed deformation, resulting in biases in the experimental data. Summary of the Invention

[0006] This invention provides a measurement system and method for laboratory pore pressure response and seabed liquefaction standard experiments. It is applicable to pore pressure response and seabed liquefaction standard experiments and can effectively avoid the influence of seabed deformation on experimental data during the experiment.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A measurement system for laboratory pore pressure response and seabed liquefaction standard experiments includes a sand-fixing structure for suppressing model seabed deformation. The sand-fixing structure includes a sand-fixing net, a second slide rail, a third slide rail, and a roller. The aforementioned sand-fixing net is made of metal or plastic, and the pore size of the sand-fixing net is equal to the particle size of the sand on the model seabed.

[0009] The four sides of the sand-fixing net are defined as the first side strip, the second side strip, the third side strip, and the fourth side strip, arranged in the order of the first side strip, the second side strip, the fourth side strip, and the third side strip. The fourth side strip is connected to the roller and is parallel to the central axis of the roller. The second side strip and the third side strip are respectively embedded in the grooves of the second slide rail and the third slide rail, and are slidably connected to the corresponding slide rail. The second slide rail and the third slide rail are arranged in parallel.

[0010] The first side strip of the sand-fixing net is pulled by the position of the roller, and the second and third side strips slide relative to the second and third slide rails until the formed sand-fixing net can cover the model seabed. The formed sand-fixing net is fixed on the second or third slide rail by the fixing clip.

[0011] The measurement system also includes a pore pressure gauge, which is fixed to the shaped sand-fixing net and used to measure the pore pressure response and liquefaction conditions in the model seabed area covered by the sand-fixing net;

[0012] As a further preferred embodiment of the present invention, the measuring end of the aforementioned pore pressure gauge is buried in the model seabed covered by the sand-fixing net, and it is connected to the data box via a data cable;

[0013] As a further preferred embodiment of the present invention, the fixing clamp includes a clamping body portion, one end of the transverse portion of which extends outward and bends to form a slot, the slot being engaged on the first slide rail or the second slide rail, and the other end of the transverse portion being fixed to the side of the sand-fixing net.

[0014] Connect the hand-held block to the top of the horizontal section;

[0015] As a further preferred embodiment of the present invention, toothed fixing blocks are fixed at the center positions of both ends of the scroll, wherein the toothed fixing blocks are toothed structures arranged radially on the outside of the columnar blocks;

[0016] The ends of the first slide rail and the second slide rail are respectively matched with the toothed fixing blocks at the ends of the corresponding scrolls. When the scroll is rotated, its toothed structure meshes with the ends of the first or second slide rails and rotates.

[0017] The method of using the measurement system for laboratory pore pressure response and seabed liquefaction standard experiments specifically includes the following steps:

[0018] Step S1: Select metal or plastic to make a sand-fixing mesh with matching pore size according to the size of the soil particles in the model seabed;

[0019] Step S2: Connect the fourth strip of the sand-fixing net to the roll;

[0020] Step S3: Pull the first edge strip of the sand-fixing net located on the outside. The second and third edge strips of the sand-fixing net slide in the corresponding second and third slide rails. When the length of the sand-fixing net pulled out reaches the preset length for the experiment, use a fixing frame to fix the sand-fixing net on the second or third slide rail.

[0021] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

[0022] 1. The measurement system provided by this invention for laboratory pore pressure response and seabed liquefaction standard experiments can effectively reduce the impact of soil scour deformation on the experiment.

[0023] 2. The measurement system provided by this invention for laboratory pore pressure response and seabed liquefaction standard experiments is applicable to scenarios that fully meet the requirements of laboratory standard experiments, and also meets the experimental needs of soils with different particle sizes.

[0024] 3. The measurement system provided by this invention for laboratory pore pressure response and seabed liquefaction standard experiments is simple in structure, easy to install, widely applicable, and highly operable based on its usage method. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This is a schematic diagram of sand ripples appearing on a model seabed during an experiment using existing technology;

[0027] Figure 2 This is a schematic diagram showing that no sand ripples appeared on the surface of the model seabed during the experiment using the measurement system provided in this application;

[0028] Figure 3 This is a schematic diagram of the overall structure of a preferred embodiment provided by the present invention;

[0029] Figure 4 This is a schematic diagram of the structure after installing the orifice manometer in a preferred embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the connection between the sand-fixing net and the roller in a preferred embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the sand-fixing net structure in a preferred embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the fixing clip structure in a preferred embodiment of the present invention.

[0033] In the diagram: 1 is the sand-fixing net, 2 is the second slide rail, 3 is the third slide rail, 4 is the roller, 5 is the first side strip, 6 is the second side strip, 7 is the fourth side strip, and 8 is the third side strip. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of this application, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of the present invention.

[0035] Before describing the measurement system provided in this application, let's first explain the relevant knowledge involved in standard experiments. First, a wave is a physical phenomenon in which disturbances or physical information propagate in space. In fluid mechanics, a gravity wave refers to a wave within a liquid medium or between two media (such as the atmosphere and the ocean), whose restoring force comes from gravity or buoyancy. When a small mass of liquid leaves the surface or enters a region of different liquid density within a liquid, it will oscillate between equilibrium states in a wave-like manner under the influence of gravity. Ocean waves and tsunamis are manifestations of gravity waves. There are many quantities used to describe waves, among which wave height, wavelength, and period are three very important physical quantities used to describe waves.

[0036] Under the cyclic wave pressure exerted on the seabed surface by wave loads, the effective stress field and excess pore pressure field within the marine foundation or seabed soil vary with time and spatial location. Excess pore pressure within the soil may gradually accumulate, and the effective stress of the soil skeleton will correspondingly decrease. Liquefaction occurs when the effective stress of the soil decreases to zero. Clearly, as explained in the background section, seabed deformation is an irrelevant variable in standard experiments for verifying pore pressure response and soil liquefaction; therefore, it is necessary to minimize seabed deformation as much as possible.

[0037] In existing laboratory physical models, after a period of wave loading, it is inevitable that the surface of the model seabed will exhibit phenomena such as... Figure 1 To reduce the occurrence of sand streaks, as shown in the diagram, this application provides a measurement system for laboratory pore pressure response and seabed liquefaction standard experiments. Figure 3As shown, the overall structure includes a sand-fixing structure for suppressing deformation of the model seabed. The sand-fixing structure includes a sand-fixing net, a second slide rail, a third slide rail, and a scroll. The aforementioned sand-fixing net is made of metal or plastic. Using the aforementioned flexible material to make the sand-fixing net ensures that the sand-fixing net can be rolled up on the scroll at any time. The aperture size of the sand-fixing net is equal to the particle size of the sand on the model seabed, which ensures that the experimental results have good effects.

[0038] The applicant conducted relevant experiments regarding the selection of the mesh size for the sand-fixing mesh. In the preliminary experiment, the sand-fixing mesh was 80 mesh, i.e., the aperture was 0.178 mm, and the median particle size of the sand was 0.18 mm. Figure 2 As shown, after 200 wave cycles, the deformation of the sand surface is very small, and the value measured by the pore pressure gauge in the seabed sand is basically the same as that without the sand-fixing net. This indicates that the sand-fixing net has little effect on the pore water pressure. Therefore, the deformation of the seabed sand is effectively reduced while ensuring the reliability of the experimental data.

[0039] Figure 6 As shown, the four sides of the sand-fixing net are defined as the first side strip, the second side strip, the third side strip, and the fourth side strip, arranged in the order of the first side strip, the second side strip, the fourth side strip, and the third side strip. The fourth side strip is connected to the scroll and is parallel to the central axis of the scroll. The second and third side strips are respectively embedded in the grooves of the second and third slide rails, and are slidably connected to their corresponding slide rails. The second and third slide rails are arranged in parallel. The design of the second and third slide rails can control the stability of the sand-fixing net's movement, and considering the relevant designs of most experimental water tanks in scientific research institutions, the second and third slide rails can be easily fixed to the side wall of the experimental water tank. The first side strip of the sand-fixing net is pulled by the scroll position, and the second and third side strips slide relative to the second and third slide rails until the formed sand-fixing net can cover the model seabed. The formed sand-fixing net is fixed to the second or third slide rail by a fixing clip.

[0040] In the experiment, in order to ensure the smooth connection between the sand-fixing net and the roll, in this application, toothed fixing blocks are fixed at the center positions of both ends of the roll. The toothed fixing blocks are toothed structures arranged radially on the outside of the columnar blocks. The ends of the first slide rail and the second slide rail are matched with the toothed fixing blocks at the corresponding ends of the roll. When the roll is rotated, its toothed structure meshes with the ends of the first slide rail or the second slide rail and rotates.

[0041] The preferred embodiment also provides the specific structure of the fixing clip. Figure 7 As shown, it includes a clamping part, one end of which extends outward and bends to form a slot, which is engaged with the first or second slide rail, and the other end of the horizontal part is fixed to the side of the sand-fixing net; a hand-held block is connected to the top of the horizontal part to facilitate the operator to pull the sand-fixing net.

[0042] Figure 4 As shown, the measurement system also includes a pore pressure gauge, which is fixed to the shaped sand-fixing net and used to measure the pore pressure response and liquefaction conditions in the model seabed area covered by the sand-fixing net. The measuring end of the aforementioned pore pressure gauge is buried in the model seabed covered by the sand-fixing net and is connected to a data box via a data cable. The data box can read the pore pressure data at the measured location.

[0043] The present application also provides a method for using the measurement system for laboratory pore pressure response and seabed liquefaction standard experiments, specifically including the following steps:

[0044] Step S1: Select metal or plastic to make a sand-fixing mesh with matching pore size according to the size of the soil particles in the model seabed;

[0045] Step S2: Connect the fourth strip of the sand-fixing net to the roll;

[0046] Step S3: Pull the first edge strip of the sand-fixing net located on the outside. The second and third edge strips of the sand-fixing net slide in the corresponding second and third slide rails. When the length of the sand-fixing net pulled out reaches the preset length for the experiment, use a fixing frame to fix the sand-fixing net on the second or third slide rail.

[0047] In summary, the measurement system provided in this application for standard laboratory experiments on pore pressure response and seabed liquefaction reduces the deformation of the seabed by covering it with a sand-fixing net of appropriate pore size. The pore pressure gauge is fixed at the corresponding position of the sand-fixing net to measure the pore pressure response and liquefaction of the seabed below the sand-fixing net coverage area, thereby realizing the measurement of standard experiments on pore pressure response and seabed liquefaction.

[0048] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0049] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0050] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0051] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A measurement system for laboratory pore pressure response and seabed liquefaction standard experiments, characterized in that: It includes a sand-fixing structure to suppress deformation of the model seabed. The sand-fixing structure includes a sand-fixing net, a second slide rail, a third slide rail, and a roller. The aforementioned sand-fixing net is made of metal or plastic, and the size of the pores of the sand-fixing net is equal to the particle size of the sand on the model seabed. The four sides of the sand-fixing net are defined as the first side strip, the second side strip, the third side strip, and the fourth side strip, arranged in the order of the first side strip, the second side strip, the fourth side strip, and the third side strip. The fourth side strip is connected to the roller and is parallel to the central axis of the roller. The second side strip and the third side strip are respectively embedded in the grooves of the second slide rail and the third slide rail, and are slidably connected to the corresponding slide rail. The second slide rail and the third slide rail are arranged in parallel. The first side strip of the sand-fixing net is pulled by the position of the roller, and the second and third side strips slide relative to the second and third slide rails until the formed sand-fixing net can cover the model seabed. The formed sand-fixing net is fixed on the second or third slide rail by the fixing clip. The measurement system also includes a pore pressure gauge, which is fixed to the shaped sand-fixing net and used to measure the pore pressure response and liquefaction conditions in the model seabed area covered by the sand-fixing net; The fixing clamp includes a clamp body, one end of which extends outward and bends to form a slot, which is engaged with the first or second slide rail, and the other end of the horizontal part is fixed to the side of the sand-fixing net; a hand-held block is connected to the top of the horizontal part. Toothed fixing blocks are fixed at the center positions of both ends of the scroll. The toothed fixing blocks are formed by setting toothed structures along the radial direction on the outside of the columnar blocks. The ends of the first slide rail and the second slide rail are respectively matched with the toothed fixing blocks at the ends of the corresponding scrolls. When the scroll is rotated, its toothed structure meshes with the ends of the first or second slide rails and rotates.

2. The measurement system for laboratory pore pressure response and seabed liquefaction standard experiments according to claim 1, characterized in that: The measuring end of the aforementioned pore pressure gauge is buried in the model seabed covered by sand-fixing netting, and it is connected to the data box via a data cable.

3. The method of using the measurement system for laboratory pore pressure response and seabed liquefaction standard experiments as described in claim 1, characterized in that: Specifically, the following steps are included: Step S1: Select metal or plastic to make a sand-fixing mesh with matching pore size according to the size of the soil particles in the model seabed; Step S2: Connect the fourth strip of the sand-fixing net to the roll; Step S3: Pull the first edge strip of the sand-fixing net located on the outside. The second and third edge strips of the sand-fixing net slide in the corresponding second and third slide rails. When the length of the sand-fixing net pulled out reaches the preset length for the experiment, use a fixing frame to fix the sand-fixing net on the second or third slide rail.

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