Visualized test device and method for interaction between high-pressure rotary jet and soft soil

Abstract

The present application belongs to the technical field of geotechnical engineering and indoor test, and provides a visual test device and method for interaction between high-pressure rotary jet flow and soft soil, which comprises a detachable model box, a jet medium simulation system, a high-pressure rotary jet flow generation system, an overburden pressure simulation system, a data acquisition system and a tracing system.The test device has the advantages of high visual degree, detachability, easy assembly and easy production.The jet medium simulation system has significant shear thinning characteristics, and has a high degree of reduction of the non-Newtonian fluid properties of cement slurry, which not only overcomes the problem of easy blockage of the pipeline, but also avoids distortion defects.The trajectory of the fluorescent powder particles in the jet medium simulation system can be captured by a high-speed camera under the irradiation of the pulsating laser beam generated by the pulsating laser, so as to accurately reproduce the flow field information of the high-pressure rotary jet flow in the soft soil.

Description

Technical Field

[0001] This invention belongs to the technical fields of geotechnical engineering and indoor testing, and specifically relates to a visualization test device and method for the interaction between high-pressure swirling jets and soft soil. Background Technology

[0002] High-pressure jet grouting technology, as a widely used foundation treatment method, has the advantages of simple construction operation, wide applicability, and good durability of jet grouting reinforced bodies. It has been widely used in engineering fields such as foundation underpinning, foundation pit support, foundation reinforcement, and water-stop curtain.

[0003] Although high-pressure jet grouting technology has made significant progress in equipment development, construction techniques, and design calculations, core scientific issues such as the coupling mechanism between the high-pressure jet stream and the soil remain poorly understood. This has become a key technological bottleneck restricting the application expansion and intelligent, low-carbon, and green development of high-pressure jet grouting foundation treatment technology. The interaction between the high-pressure jet stream and the soil involves a series of complex physical and mechanical phenomena, such as the interaction between the high-speed jet and the porous medium (soil), seepage-stress coupling, and energy exchange between the high-speed jet and the surrounding fluid. Currently, research on the interaction between the high-pressure jet stream and the soil mainly relies on numerical simulation and field tests, lacking visual physical model test devices and methods. This hinders in-depth exploration of the pile formation response laws, such as the attenuation of high-speed jet pressure, the increase of cutting distance, and the evolution of the soil displacement field during high-pressure jet grouting pile formation. Therefore, it is necessary to further develop visualization test devices and methods for studying the interaction between high-pressure jet grouting and soft soil. This is of great theoretical and practical significance for revealing the coupling mechanism between high-pressure jet grouting and soil and promoting the development of high-pressure jet grouting foundation treatment technology towards intelligence, low carbonization, and greening. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides a visualization test device for the interaction between high-pressure vortex jet and soft soil, including a detachable model box, a jet medium simulation system, a high-pressure vortex jet generation system and an overlying soil pressure simulation system, a data acquisition system, and a tracer system;

[0006] The detachable model box includes a bottom panel, a left panel, a right panel, a front panel, and a rear panel. The bottom panel, left panel, and right panel are connected by integral welding. The front panel and rear panel are made of transparent tempered glass. The front panel and rear panel are connected to the bottom panel, left panel, and right panel by bolts. A through hole is provided on the central axis of the left panel, located at 1 / 4 of the distance from the bottom panel, for the high-pressure vortex jet of the high-pressure vortex jet generation system to enter the interior of the detachable model box.

[0007] The high-pressure vortex jet generation system includes a solution storage tank, a high-pressure pump, a first explosion-proof pipe, a second explosion-proof pipe, a high-pressure nozzle, a nozzle configuration adjuster, a pressure gauge, and an electromagnetic flowmeter. The solution storage tank stores the jet medium simulation system. The high-pressure pump pressurizes the jet medium simulation system to a predetermined high-pressure vortex jet injection pressure. The first and second explosion-proof pipes are made of stainless steel and can withstand a maximum pressure of not less than 14 MPa. The left end of the first explosion-proof pipe is connected to the solution storage tank, and its right end is connected to the high-pressure pump. The left end of the second explosion-proof pipe is connected to the high-pressure pump, and its right end is connected to the high-pressure nozzle. The high-pressure nozzle is made of brass, with one end connected to the second explosion-proof pipe and the other end embedded in a pre-drilled through hole on the left panel of the detachable model box. Its function is to transmit the high-pressure vortex jet, pressurized to a predetermined pressure by a high-pressure pump, to a detachable model box to cut and break soft soil. The nozzle structure adjuster is embedded in the high-pressure nozzle and is used to adjust the three key technical indicators of the high-pressure nozzle: nozzle diameter, linear aspect ratio, and narrow angle. The nozzle structure adjuster is 3D printed from transparent photosensitive resin material. The external dimensions of the nozzle structure adjuster are completely consistent with the internal dimensions of the high-pressure nozzle. The internal dimensions of the nozzle structure adjuster can be precisely 3D printed according to the experimental parameters. The pressure gauge is installed on the second explosion-proof pipe and its function is to monitor the high-pressure vortex jet pressure reached by the high-pressure pump. The electromagnetic flowmeter is installed on the second explosion-proof pipe and its function is to measure the reduction of the jet medium simulation system in the solution storage tank.

[0008] The jet medium simulation system includes purified water, sodium polyacrylate, and fluorescent powder particles; the purified water is used as a solvent; the sodium polyacrylate is used as a solute and is dissolved in the purified water.

[0009] The overburden pressure simulation system includes a reaction frame, a force transmission beam, a loading plate, and jacks. The reaction frame is a hollow rectangular steel pipe used to provide the supporting reaction force required to simulate overburden pressure. The force transmission beam is fixed to the left and right panels of the detachable model box by bolts and nuts, and its function is to fix the reaction frame to the detachable model box. The loading plate is a solid rectangular steel plate used to apply uniform pressure to the surface of the model soil inside the detachable model box. The reaction frame is placed between the force transmission beams, and the jacks are placed between the reaction frame and the loading plate, and their function is to provide a load source for simulating overburden pressure.

[0010] The data acquisition system includes a measuring frame, a piezoresistive pressure sensor, a first pulsed laser, and a second pulsed laser. The measuring frame is mounted on the left and right panels of the detachable model box, and is located at 3 / 4 of the distance from the bottom panel, for fixing the piezoresistive pressure sensor. The piezoresistive pressure sensor is arranged at equal intervals along a direction parallel to the axis of the high-pressure swirling jet, and its position is slightly offset from the axis of the high-pressure swirling jet on the horizontal plane to reduce the adverse effect on the pressure attenuation characteristics of the high-pressure swirling jet. The first pulsed laser is arranged in front of the front panel of the detachable model box to generate a pulsed laser beam perpendicular to the front panel of the detachable model box. The second pulsed laser is arranged in front of the right panel of the detachable model box to generate a pulsed laser beam parallel to the front panel of the detachable model box.

[0011] The data acquisition system also includes a strain gauge, an LED light source, a high-speed camera, a camera calibration plate, and a computer. The strain gauge is used to acquire data from a piezoresistive pressure sensor in real time. The LED light source is arranged around the high-speed camera, and its light source is stably focused on the front panel of the detachable model box to ensure the quality of the acquired digital images. The high-speed camera is mounted on the outside of the front panel of the detachable model box via a tripod and is used to record the development and evolution of the soil displacement field under the impact of high-pressure swirling jet flow during the scaled-down physical model test in real time. A certain number of control points are set in the camera calibration plate to correct the analysis errors caused by geometric distortion of the captured images. The computer is equipped with PIVlab and Tecplot programs based on a graphical user interface to analyze the acquired data images and obtain the soil velocity field.

[0012] The tracer system includes a nano-coating material, petroleum jelly, and a thin layer of fine sand tracer particles. The nano-coating material is uniformly coated on the inner wall of the front panel of the detachable model box to reduce the adhesion between the soft soil and the inner wall of the front panel of the detachable model box. The petroleum jelly is uniformly coated on the surface of the nano-coating material. The thin layer of fine sand tracer particles is uniformly dispersed on the surface of the petroleum jelly to move with the soil, thereby reflecting the development and evolution of the soil displacement field under the shearing action of the high-pressure vortex jet.

[0013] Furthermore, the gaps between the front panel, rear panel, bottom panel, left panel, and right panel are filled with waterproof foam to prevent the high-pressure vortex jet from leaking out of the gaps.

[0014] Furthermore, the length and height of the detachable model box are 8 to 10 times its width.

[0015] Furthermore, the thickness of the front panel and the rear panel is not less than 3cm.

[0016] Furthermore, the preparation process of the jet medium simulation system is as follows: add pure water to the solution storage tank to near the top height, add sodium polyacrylate with a mass fraction of 0.1% to 0.3%; then add phosphor particles with a diameter of 5 to 8 μm and a mass concentration of 0.1 g / ml, and stir evenly.

[0017] Furthermore, the piezoresistive pressure sensor is positioned at the same height as the through hole on the left panel of the detachable model box.

[0018] Furthermore, the piezoresistive pressure sensors are arranged at equal intervals along a direction parallel to the axis of the high-pressure swirling jet, and their positions are slightly offset from the axis of the high-pressure swirling jet on the horizontal plane.

[0019] Furthermore, the soft soil required for the experiment is saturated soft soil with fluidity, and the method for preparing the saturated soft soil with fluidity is as follows:

[0020] (1) Sampling was taken from the engineering site in the soft soil area;

[0021] (2) The liquid limit value of soft soil was determined using a combined liquid and plastic limit tester;

[0022] (3) The soft soil samples were placed in batches in a 4-8KW oven for testing and dried. The drying temperature was set to 100-120℃ and the drying time was 24h to obtain dried soft soil test blocks.

[0023] (4) The dry soft soil test block is initially crushed, and then the initially crushed soft soil test block is further crushed by a pulverizer to obtain soft soil powder;

[0024] (5) Prepare five groups of indoor saturated quick shear samples with different moisture contents from soft soil powder, and conduct indoor saturated quick shear tests to obtain the most suitable moisture content corresponding to the maximum fluidity (i.e. the minimum cohesion).

[0025] (6) Add the soft soil powder and water with the optimal moisture content to a mixer simultaneously, and vacuum mix for 2 hours to obtain the saturated soft soil with fluidity required for the model test. The drying temperature is 100-120℃. This invention provides a visualization test method for the interaction between high-pressure vortex jet and soft soil. The method is applicable to the visualization test device for the interaction between high-pressure vortex jet and soft soil described above. The test method includes:

[0026] Preparation of saturated soft soil:

[0027] (1) Samples were taken from the engineering site in the soft soil area; (2) The liquid limit value of the soft soil was determined using a combined liquid and plastic limit tester; (3) The soft soil samples were placed in batches in a 4-8KW oven for drying, with the drying temperature set at 100-120℃ and the drying time at 24h, to obtain dried soft soil test blocks; (4) The dried soft soil test blocks were initially crushed, and then further crushed using a pulverizer to obtain soft soil powder; (5) The soft soil powder was prepared into 5 groups of indoor saturated quick-shear test samples with different moisture contents, and indoor saturated quick-shear tests were carried out to obtain the optimal moisture content corresponding to the maximum fluidity (i.e., the minimum cohesion); (6) The soft soil powder and water with the optimal moisture content were added to a mixer at the same time, and vacuum stirred for 2h to obtain the fluid saturated soft soil required for the model test. The drying temperature was 100-120℃.

[0028] Detachable model box assembly: Connect the bottom panel, left panel, right panel, front panel, and rear panel together;

[0029] Tracer system installation: Nano-coating material, petroleum jelly, and thin layer of fine sand tracer particles are uniformly applied to the inner wall of the front panel of the detachable model box.

[0030] Backfilling and installation of the measuring frame: The prepared saturated soft soil is filled into the detachable model box in layers until the surface of the filled soil reaches the predetermined installation position of the measuring frame, at which point the backfilling is stopped; the measuring frame is installed at the predetermined positions on the left and right panels of the detachable model box, specifically 3 / 4 of the distance from the bottom panel;

[0031] Piezoresistive pressure sensor installation: Fix the piezoresistive pressure sensors at equal intervals along the axis of the measuring frame, adjust the height of the piezoresistive pressure sensors so that they are at the same height as the through holes reserved on the left panel of the detachable model box; connect the other end of the wiring of the piezoresistive pressure sensor to the strain gauge.

[0032] Filling with excess soil: Continue to fill the prepared saturated soft soil in layers into the removable model box until the surface of the filled soil is slightly lower than the top of the removable model box, then the filling is finished.

[0033] Installation of the overburden pressure simulation system: Place a loading plate on the fill surface, and then install the jack, force transmission beam, and reaction frame in sequence. Fix the reaction frame to the force transmission beam, and fix the force transmission beam to the left and right panels of the detachable model box to complete the installation of the overburden pressure simulation system.

[0034] Installation of the high-pressure vortex jet generation system: Based on the three technical parameters of the high-pressure nozzle required for the experiment—nozzle diameter, linear aspect ratio, and narrow angle—a nozzle structure adjuster matching the internal dimensions of the high-pressure nozzle was 3D printed using transparent photosensitive resin material and embedded into the high-pressure nozzle. The high-pressure nozzle was then inserted into the pre-drilled through hole on the left panel of the detachable model box and fixed in place. The left end of the high-pressure nozzle was connected to the second explosion-proof pipe, and a pressure gauge and an electromagnetic flowmeter were installed on the second explosion-proof pipe. Then, the high-pressure pump, the first explosion-proof pipe, and the solution storage tank were installed in sequence to complete the installation of the high-pressure vortex jet generation system.

[0035] Preparation of the jet medium simulation system: Add pure water to the solution storage tank until it is close to the top height, then add sodium polyacrylate with a mass fraction of 0.2%; then add phosphor particles with a diameter of 6μm and a mass concentration of 0.1g / ml, stir evenly, and the jet medium simulation system is prepared.

[0036] High-speed camera installation and calibration: The high-speed camera is fixed to the front of the detachable model box using a tripod, and LED light sources are arranged around it to ensure that the light sources are stably focused on the front panel of the detachable model box, so as to ensure the quality of the acquired digital images; the high-speed camera connected to the computer is calibrated using a camera calibration board, and the analysis error caused by geometric distortion of the captured images is corrected.

[0037] Pulsating laser placement: A first pulsed laser and a second pulsed laser are placed in front of the front panel and right panel of the detachable model box, respectively. The orientation is adjusted so that the pulsed laser beams emitted by the first pulsed laser and the second pulsed laser are perpendicular to and parallel to the front panel of the detachable model box, respectively.

[0038] Overburden pressure load application: Use jacks to steadily apply pressure to the reaction frame in the overburden pressure simulation system until the pressure value of the loading plate acting on the saturated soft soil surface reaches the predetermined value.

[0039] The test was started by connecting the high-pressure pump power supply, setting the pressure value of the high-pressure vortex jet, and turning on the strain gauge, high-speed camera, LED light source, first pulse laser, second pulse laser, and computer. A visualization model test of the interaction between the high-pressure vortex jet and saturated soft soil was conducted under the conditions that the pressure of the high-pressure vortex jet was the set pressure value and the overlying soil pressure was the predetermined value. During the test, data such as the pressure decay law of the high-pressure vortex jet and the development and evolution law of the soil displacement field were collected and recorded in real time, and the growth of the distance that the high-pressure vortex jet cuts the soil was observed.

[0040] Shutdown and cleaning: When the distance of the high-pressure vortex jet cutting the soil remains basically stable, turn off the power of the high-pressure pump, stop the model test, remove the overlying soil pressure simulation system, excavate the saturated soft soil inside the detachable model box, clean the detachable model box, and analyze the test data.

[0041] A quantitative model was established: Data collected by piezoresistive pressure sensors during the experiment was analyzed and processed to obtain experimental data on the attenuation law of high-pressure swirling jet pressure with distance and time. The data processing method for the attenuation law of high-pressure swirling jet pressure with distance is as follows: Using the horizontal distance between the piezoresistive pressure sensor and the high-pressure nozzle as the abscissa, and the pressure collected by different piezoresistive pressure sensors at multiple times (10s, 20s, 30s, 40s, 50s) after reaching the predetermined initial pressure value of the high-pressure swirling jet as the ordinate, a scatter plot was drawn. Multiple spline curves were used to fit the scatter plots to establish an empirical formula characterizing the relationship between high-pressure swirling jet pressure and distance. The data processing method for the attenuation law of high-pressure swirling jet pressure with time is as follows: Using multiple times (10s, 20s, 30s, 40s, 50s) after reaching the pressure value of the high-pressure swirling jet as the abscissa, and the pressure collected by piezoresistive pressure sensors at different distances from the high-pressure nozzle as the ordinate, a scatter plot was drawn. Multiple spline curves were used to fit the scatter plots to establish an empirical formula characterizing the relationship between high-pressure swirling jet pressure and time.

[0042] Analysis of Evolution Laws: Data acquired by high-speed cameras during the experiment were processed to obtain the development and evolution of the soil displacement field and the distribution law of the high-pressure vortex jet flow field. The specific method is as follows: The soil displacement field data was imported into PIVlab and Tecplot software to plot the soil displacement and high-pressure vortex jet flow field contour maps at multiple different times (10s, 20s, 30s, 40s, and 50s) after the predetermined initial pressure of the high-pressure vortex jet flow. The box-counting method was used to calculate the fractal dimension values ​​of the soil displacement contour maps and the high-pressure vortex jet flow field contour maps at different times.

[0043] The present invention has the following beneficial effects:

[0044] (1) The test device of the present invention has the advantages of high visualization, detachability, convenient assembly and easy manufacturing, and overcomes the shortcomings of traditional scaled physical model test devices that cannot accurately reproduce the development and evolution law of soil displacement field under high pressure jet shearing action.

[0045] (2) The ingenious collaboration of components such as the detachable model box, the high-pressure vortex jet generation system, and the overlying soil pressure simulation system in this invention realizes controllable parameter testing technology, which can conveniently and efficiently carry out sensitivity test research on various key parameters (including high-pressure vortex jet pressure, overlying soil pressure, undrained shear strength of soil, and nozzle shape).

[0046] (3) The jet medium simulation system of the present invention has significant shear thinning characteristics and high reproduction of the non-Newtonian fluid characteristics of cement slurry. It not only overcomes the problem of easy pipe blockage when using cement slurry for testing, but also avoids the distortion defect when using pure water to simulate high pressure vortex jet flow. In addition, the trajectory of the phosphor particles in the jet medium simulation system of the present invention can be captured by a high-speed camera under the irradiation of the pulsed laser beam emitted by the pulsed laser, thereby accurately reproducing the flow field information of high pressure vortex jet flow in soft soil.

[0047] (4) The nozzle structure adjuster of the present invention is made of transparent photosensitive resin material, which is not only high in strength but also highly malleable. It can be easily made into a nozzle shape with precise dimensions through 3D printing technology. It is used in conjunction with a high-pressure nozzle to efficiently realize the parameter sensitivity test research of different nozzle shapes.

[0048] (5) The present invention arranges piezoresistive pressure sensors at equal intervals along the direction parallel to the axis of the high-pressure swirling jet, and adjusts the measuring frame fixed at a specific position on the left and right panels of the detachable model box so that the position of the piezoresistive pressure sensors is slightly deviated from the axis of the high-pressure swirling jet on the horizontal plane. This not only reduces the adverse effect on the pressure attenuation characteristics of the high-pressure swirling jet, but also achieves high-precision capture of the pressure evolution characteristics of the high-pressure swirling jet as it moves away from the high-pressure nozzle.

[0049] (6) This invention innovatively utilizes nano-coating materials, petroleum jelly, and thin-layer fine sand tracer particles, and applies them evenly to the inner wall of the front panel of the detachable model box in a specific order. Based on the principle of the combined effect of nano-penetration and lubrication and friction reduction, it effectively solves the tricky problem of "wall smearing" in the application of particle image velocimetry technology in the physical model test of soft soil scale-down, thereby visually realizing the accurate capture of the real displacement field movement law of soil during the interaction between high-pressure vortex jet and soft soil. Attached Figure Description

[0050] Figure 1 This is the front view of the detachable model box of the present invention.

[0051] Figure 2 This is a left view of the detachable model box of the present invention.

[0052] Figure 3 This is a top view of the detachable model box of the present invention.

[0053] Figure 4 This is a schematic diagram of the jet medium simulation system of the present invention.

[0054] Figure 5 This is a schematic diagram of the high-pressure swirling jet generation system of the present invention.

[0055] Figure 6 This is a front view of the nozzle configuration adjuster of the present invention.

[0056] Figure 7 This is a left view of the nozzle configuration adjuster of the present invention.

[0057] Figure 8 This is a top view of the nozzle structure adjuster of the present invention.

[0058] Figure 9 This is a schematic diagram of the overlying soil pressure simulation system of the present invention.

[0059] Figure 10 This is a schematic diagram of the data acquisition system of the present invention.

[0060] Figure 11 This is a schematic diagram of the tracer system of the present invention.

[0061] Figure 12 This is a schematic diagram of the completed assembly of the visualization test device of the present invention.

[0062] Figure 13 This is a flowchart of the visualization test method of the present invention.

[0063] In the diagram: Detachable model box 1, bottom panel 1-1, left panel 1-2, right panel 1-3, front panel 1-4, rear panel 1-5, bolt 1-6, through hole 1-2-1, jet medium simulation system 2, pure water 2-1, sodium polyacrylate 2-2, fluorescent powder particles 2-3, high-pressure vortex jet generation system 3, solution storage tank 3-1, high-pressure pump 3-2, first explosion-proof pipe 3-3, second explosion-proof pipe 3-4, high-pressure nozzle 3-5, nozzle structure adjuster 3-5-2, pressure gauge 3-6, electromagnetic flowmeter 3-7, high pressure 3-5-1 Swirling jet stream, 4 Overlying soil pressure simulation system, 4-1 Reaction frame, 4-2 Force transmission beam, 4-3 Loading plate, 4-4 Jack, 5 Data acquisition system, 5-1 Strain gauge, 5-2 Measuring frame, 5-3 Piezoresistive pressure sensor, 5-4 LED light source, 5-5 High-speed camera, 5-6 Camera calibration board, 5-7 Computer, 5-5-1 Tripod, 5-8 First pulsed laser, 5-9 Second pulsed laser, 6 Tracer system, 6-1 Nano-coating material, 6-2 Vaseline, 6-3 Thin-layer fine sand tracer particles. Detailed Implementation

[0064] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments are only specific illustrations of the invention and should not be regarded as limitations on the invention. The purpose of the embodiments is to enable those skilled in the art to better understand and reproduce the technical solution of the present invention. The scope of protection of the present invention should still be determined by the scope defined in the claims.

[0065] like Figure 1-12 As shown, this invention provides a visualization experimental device for the interaction between high-pressure vortex jet and soft soil. The device comprises six parts: a detachable model box 1, a jet medium simulation system 2, a high-pressure vortex jet generation system 3, an overburden pressure simulation system 4, a data acquisition system 5, and a tracer system 6.

[0066] like Figure 1-3As shown, the detachable model box 1 includes a bottom panel 1-1, a left panel 1-2, a right panel 1-3, a front panel 1-4, a rear panel 1-5, and bolts 1-6. The overall dimensions of the detachable model box 1 are determined based on similarity theory, and considering the elimination of boundary effects as much as possible, its length and height are 8 to 10 times its width. The bottom panel 1-1, left panel 1-2, and right panel 1-3 are made of steel and are connected by integral welding. The front panel 1-4 and rear panel 1-5 are made of transparent tempered glass with a thickness of not less than 3 cm to facilitate the creation of a model. Visual acquisition of volume displacement field information; the front panel 1-4 and the rear panel 1-5 are connected to the bottom panel 1-1, the left panel 1-2, and the right panel 1-3 by bolts 1-6; the gaps between the front panel 1-4, the rear panel 1-5 and the bottom panel 1-1, the left panel 1-2, and the right panel 1-3 are filled with waterproof foam to prevent the high-pressure vortex jet from leaking out of the gaps; a through hole 1-2-1 is reserved on the central axis of the left panel 1-2, and the through hole 1-2-1 is located at 1 / 4 of the distance from the bottom panel to provide a channel for the high-pressure vortex jet to enter the interior of the detachable model box 1.

[0067] like Figure 4 As shown, the jet medium simulation system 2 includes pure water 2-1, sodium polyacrylate 2-2, and phosphor particles 2-3. The trajectory of the phosphor particles can be captured by a high-speed camera under the irradiation of a pulsed laser beam emitted by a pulsed laser, thereby accurately reproducing the flow field information of the high-pressure swirling jet in soft soil. The pure water 2-1 is used as a solvent; the sodium polyacrylate 2-2 is used as a solute and is dissolved in the pure water 2-1; the mass fraction of the sodium polyacrylate 2-2 is 0.1% to 0.3%; the phosphor particles 2-3 are uniformly distributed in the mixture of sodium polyacrylate 2-2 and pure water 2-1; the mass concentration of the phosphor particles 2-3 in the mixture of sodium polyacrylate 2-2 and pure water 2-1 is 0.1 g / ml; the diameter of the phosphor particles 2-3 is 5 to 8 μm.

[0068] like Figure 5As shown, the high-pressure vortex jet generation system 3 includes a solution storage tank 3-1, a high-pressure pump 3-2, a first explosion-proof pipe 3-3, a second explosion-proof pipe 3-4, a high-pressure nozzle 3-5, a nozzle configuration adjuster 3-5-2, a pressure gauge 3-6, and an electromagnetic flowmeter 3-7. The solution storage tank 3-1 is used to store the jet medium simulation system 2. The high-pressure pump 3-2 is used to pressurize the jet medium simulation system 2 to a predetermined high-pressure vortex jet injection pressure. The first explosion-proof pipe 3-3 and the second explosion-proof pipe 3-4 are made of stainless steel, and their maximum withstand pressure is not less than 14 MPa. The left end of the first explosion-proof pipe 3-3 is connected to the solution storage tank 3-1, and its right end is connected to the high-pressure pump 3-2; the left end of the second explosion-proof pipe 3-4 is connected to the high-pressure pump 3-2, and its right end is connected to the high-pressure nozzle 3-5; the high-pressure nozzle 3-5 is made of brass, one end of which is connected to the second explosion-proof pipe 3-4, and the other end is embedded in the through hole 1-2-1 reserved on the left panel 1-2 of the detachable model box 1; the function of the high-pressure nozzle 3-5 is to transmit the high-pressure vortex jet 3-5-1, which has been pressurized to a predetermined pressure by the high-pressure pump 3-2, to the detachable model box 1 to cut and break the soft soil; Figure 6-8 As shown, the nozzle structure adjuster 3-5-2 is embedded in the high-pressure nozzle 3-5 and is used to adjust the three key technical indicators of the high-pressure nozzle 3-5: nozzle diameter, linear aspect ratio, and narrow angle. The nozzle structure adjuster 3-5-2 is 3D printed from transparent photosensitive resin material. The external dimensions of the nozzle structure adjuster 3-5-2 are completely consistent with the internal dimensions of the high-pressure nozzle 3-5. The internal dimensions of the nozzle structure adjuster 3-5-2 can be precisely 3D printed according to the test parameters. The pressure gauge 3-6 is installed on the second explosion-proof pipe 3-4 and its function is to monitor the high-pressure vortex jet pressure achieved by the high-pressure pump 3-2. The electromagnetic flowmeter 3-7 is installed on the second explosion-proof pipe 3-4 and its function is to measure the reduction of the jet medium simulation system 2 in the solution storage tank 3-1.

[0069] like Figure 9 As shown, the overburden pressure simulation system 4 includes a reaction frame 4-1, a force transmission beam 4-2, a loading plate 4-3, and a jack 4-4. The reaction frame 4-1 is a hollow rectangular steel pipe used to provide the supporting reaction force required to simulate overburden pressure. The force transmission beam 4-2 is fixed to the left panel 1-2 and right panel 1-3 of the detachable model box 1 by bolts and nuts, and its function is to fix the reaction frame 4-1 to the detachable model box 1. The loading plate 4-3 is a solid rectangular steel plate used to apply uniform pressure to the surface of the model soil inside the detachable model box 1. The jack 4-4 is set between the reaction frame 4-1 and the loading plate 4-3, and its function is to provide a load source for simulating overburden pressure.

[0070] like Figure 10As shown, the data acquisition system 5 includes a strain gauge 5-1, a measuring frame 5-2, a piezoresistive pressure sensor 5-3, an LED light source 5-4, a high-speed camera 5-5, a camera calibration plate 5-6, a computer 5-7, a first pulsed laser 5-8, and a second pulsed laser 5-9. The strain gauge 5-1 is used to acquire data from the piezoresistive pressure sensor 5-3 in real time. The measuring frame 5-2 is mounted on the left panel 1-2 and right panel 1-3 of the detachable model box 1, located at 3 / 4 of the distance from the bottom panel, and is used to fix the piezoresistive pressure sensor 5-3. The piezoresistive pressure sensors 5-3 are arranged at equal intervals along a direction parallel to the axis of the high-pressure swirling jet 3-5-1, and their positions are slightly offset from the axis of the high-pressure swirling jet 3-5-1 on the horizontal plane to reduce the adverse effect on the pressure attenuation characteristics of the high-pressure swirling jet 3-5-1. The LED light source 5-4 is arranged around the high-speed camera 5-5, and its light source is stably focused on the front panel 1-2 of the detachable model box 1. 4. To ensure the quality of the acquired digital images; the high-speed camera 5-5 is set outside the front panel 1-4 of the detachable model box 1 via a tripod 5-5-1, and is used to record in real time the development and evolution of the soil displacement field under the punching action of the high-pressure swirling jet 3-5-1 during the scaled-down physical model test; a certain number of control points are set in the camera calibration plate 5-6 to correct the analysis error caused by the geometric distortion of the captured images; the computer 5-7 is equipped with PIVlab and Tecplot programs based on a graphical user interface, and is used to analyze the acquired data images and obtain the soil velocity field; the first pulsed laser 5-8 is arranged in front of the front panel 1-4 of the detachable model box 1, and is used to generate a pulsed laser beam perpendicular to the front panel 1-4 of the detachable model box 1; the second pulsed laser 5-9 is arranged in front of the right panel 1-3 of the detachable model box 1, and is used to generate a pulsed laser beam parallel to the front panel 1-4 of the detachable model box 1.

[0071] like Figure 11 As shown, the tracer system 6 includes a nano-coating material 6-1, petroleum jelly 6-2, and a thin layer of fine sand tracer particles 6-3. The nano-coating material 6-1 is uniformly coated on the inner wall of the front panel 1-4 of the detachable model box 1 to reduce the adhesion between the soft soil and the inner wall of the front panel 1-4 of the detachable model box 1. The petroleum jelly 6-2 is uniformly coated on the surface of the nano-coating material 6-1. The thin layer of fine sand tracer particles 6-3 is uniformly dispersed on the surface of the petroleum jelly 6-2 to move with the soil, thereby reflecting the development and evolution of the soil displacement field under the shearing action of the high-pressure vortex jet 3-5-1.

[0072] In some preferred embodiments, the soft soil required for the test is saturated soft soil with fluidity, and the method for preparing the saturated soft soil with fluidity is as follows:

[0073] (1) Sampling was taken from the engineering site in the soft soil area;

[0074] (2) The liquid limit value of soft soil was determined using a combined liquid and plastic limit tester;

[0075] (3) The soft soil samples were placed in batches in a 4-8KW oven for testing and dried. The drying temperature was set to 100-120℃ and the drying time was 24h to obtain dried soft soil test blocks.

[0076] (4) The dry soft soil test block is initially crushed, and then the initially crushed soft soil test block is further crushed by a pulverizer to obtain soft soil powder;

[0077] (5) Prepare five groups of indoor saturated quick shear samples with different moisture contents from soft soil powder, and conduct indoor saturated quick shear tests to obtain the most suitable moisture content corresponding to the maximum fluidity (i.e. the minimum cohesion).

[0078] (6) Add the soft soil powder and water with the optimal moisture content to a mixer simultaneously, and vacuum mix for 2 hours to obtain the saturated soft soil with fluidity required for the model test. The drying temperature is 100-120℃. Figure 13 As shown, this invention provides a visual experimental method for the interaction between high-pressure swirling jets and soft soil. The method is applicable to the aforementioned experimental apparatus and includes the following steps:

[0079] S1 Preparation of saturated soft soil: (1) Samples were taken from the engineering site in the soft soil area; (2) The liquid limit value of the soft soil was determined by a liquid limit and plastic limit combined tester; (3) The soft soil samples were placed in batches in an oven with a power of 4-8KW for the test and dried. The drying temperature was set at 100-120℃ and the drying time was 24h to obtain dried soft soil blocks; (4) The dried soft soil blocks were initially crushed and then further crushed by a pulverizer to obtain soft soil powder; (5) The soft soil powder was prepared into 5 groups of indoor saturated quick shear samples with different moisture contents. The 5 groups of moisture contents were 1.1, 1.3, 1.5, 1.7 and 1.9 times the liquid limit value, respectively. Indoor saturated quick shear tests were carried out to obtain the most suitable moisture content corresponding to the maximum fluidity (i.e. the minimum cohesion); (6) The soft soil powder and water with the most suitable moisture content were added to the mixer at the same time and vacuum stirred for 2h to obtain the saturated soft soil with fluidity required for the model test. Drying temperature is 100-120℃. S2 Detachable model box 1 Assembly: Connect bottom panel 1-1, left panel 1-2, right panel 1-3, front panel 1-4, and rear panel 1-5 together;

[0080] S3 tracer system installation: Nano-coating material 6-1, Vaseline 6-2, and thin-layer fine sand tracer particles 6-3 are uniformly applied to the inner walls of the front panel 1-4 of the detachable model box 1.

[0081] S4 Soil filling and measuring frame installation: The prepared saturated soft soil is filled into the detachable model box 1 in layers until the surface of the filled soil reaches the predetermined installation position of the measuring frame, at which point the soil filling is stopped; the measuring frame 5-2 is installed at the predetermined positions on the left panel 1-2 and right panel 1-3 of the detachable model box, specifically at 3 / 4 of the distance from the bottom panel 1-1.

[0082] S5 Piezoresistive Pressure Sensor Installation: Fix the piezoresistive pressure sensors 5-3 at equal intervals along the axis of the measuring frame. Adjust the height of the piezoresistive pressure sensors 5-3 so that they are at the same height as the through hole reserved on the left panel of the detachable model box. Connect the other end of the wiring of the piezoresistive pressure sensor 5-3 to the strain gauge 5-1.

[0083] S6 Residual Soil Filling: Continue to fill the prepared saturated soft soil in layers into the detachable model box 1 until the surface of the filled soil is slightly lower than the top of the detachable model box, then the filling is finished.

[0084] Installation of the S7 overburden pressure simulation system: Place the loading plate 4-3 on the fill surface, and then install the jack 4-4, force transmission beam 4-2, and reaction frame 4-1 in sequence. Fix the reaction frame 4-1 to the force transmission beam 4-2, and fix the force transmission beam 4-2 to the left panel 1-2 and right panel 1-3 of the detachable model box 1 to complete the installation of the overburden pressure simulation system.

[0085] Installation of the S8 high-pressure vortex jet generation system: Based on the three technical parameters of the high-pressure nozzle 3-5 required for the experiment—nozzle diameter, linear aspect ratio, and narrow angle—a nozzle structure adjuster 3-5-2 matching the internal dimensions of the high-pressure nozzle 3-5 was 3D printed using transparent photosensitive resin material. The nozzle structure adjuster 3-5-2 was then embedded into the high-pressure nozzle 3-5. The high-pressure nozzle 3-5 was inserted into the pre-drilled through hole on the left panel of the detachable model box and fixed in place. The left end of the high-pressure nozzle 3-5 was connected to the second explosion-proof pipe 3-4. A pressure gauge 3-6 and an electromagnetic flowmeter 3-7 were installed on the second explosion-proof pipe 3-4. Then, the high-pressure pump 3-2, the first explosion-proof pipe 3-3, and the solution storage tank 3-1 were installed in sequence to complete the installation of the high-pressure vortex jet generation system.

[0086] Preparation of S9 jet medium simulation system: Add pure water 2-1 to solution storage tank 3-1 until it is close to the top height, then add sodium polyacrylate 2-2 with a mass fraction of 0.2%; then add phosphor particles 2-3 with a diameter of 6μm and a mass concentration of 0.1g / ml, stir evenly, and the jet medium simulation system is prepared.

[0087] S10 High-Speed ​​Camera Installation and Calibration: The high-speed camera 5-5 is fixed to the front of the detachable model box using a tripod 5-5-1, and LED light sources 5-4 are arranged around it to ensure that the light sources are stably focused on the front panel 1-4 of the detachable model box 1, so as to ensure the quality of the acquired digital images; the high-speed camera 5-5 connected to the computer 5-7 is calibrated using a camera calibration plate 5-6, and the analysis error caused by the geometric distortion of the captured images is corrected.

[0088] S11 Pulsating Laser Layout: The first pulsed laser 5-8 and the second pulsed laser 5-9 are respectively arranged in front of the front panel 1-4 and the right panel 1-3 of the detachable model box. The orientation is adjusted so that the pulsed laser beams emitted by the first pulsed laser 5-8 and the second pulsed laser 5-9 are perpendicular to and parallel to the front panel of the detachable model box 1, respectively.

[0089] S12 Overburden pressure load application: Use jack 4-4 to steadily apply pressure to the reaction frame 4-1 in the overburden pressure simulation system until the pressure value of the loading plate 4-3 acting on the saturated soft soil surface reaches the predetermined value.

[0090] The S13 starting device begins the test: the high-pressure pump power is turned on, the pressure of the high-pressure vortex jet is set, and the strain gauge 5-1, high-speed camera 5-5, LED light source 5-4, first pulsed laser 5-8, second pulsed laser 5-9 and computer 5-7 are turned on. A visualization model test of the interaction between the high-pressure vortex jet and saturated soft soil is conducted under the conditions that the pressure of the high-pressure vortex jet is the set pressure and the pressure of the overlying soil is the predetermined value. During the test, data such as the pressure decay law of the high-pressure vortex jet and the development and evolution law of the soil displacement field are collected and recorded in real time, and the growth of the distance that the high-pressure vortex jet cuts the soil is observed.

[0091] S14 Shutdown Cleaning: When the distance of the high-pressure vortex jet cutting the soil remains basically stable, turn off the power of the high-pressure pump, stop the model test, remove the overlying soil pressure simulation system, excavate the saturated soft soil inside the detachable model box, clean the detachable model box 1, and analyze the test data.

[0092] S15 Establishing a quantitative model: Analyzing and processing the data collected by the piezoresistive pressure sensor 5-3 during the experiment, and obtaining experimental data on the attenuation law of high-pressure vortex jet pressure with distance and time; the data processing method for the attenuation law of high-pressure vortex jet pressure with distance is as follows: taking the horizontal distance between the piezoresistive pressure sensor 5-3 and the high-pressure nozzle as the abscissa, and taking the pressure collected by the piezoresistive pressure sensor 5-3 at multiple different times such as 10s, 20s, 30s, 40s, and 50s after the predetermined initial value of high-pressure vortex jet pressure as the ordinate, a scatter plot is drawn, and multiple spline curves are used to fit the scatter plot to establish an empirical formula characterizing the relationship between high-pressure vortex jet pressure and distance. The data processing method for the pressure decay law of high-pressure vortex jet over time is as follows: using multiple different times such as 10s, 20s, 30s, 40s, and 50s after the pressure value of the high-pressure vortex jet is reached as the abscissa, and using the pressure collected by the piezoresistive pressure sensor 5-3 at different distances from the high-pressure nozzle 3-5 as the ordinate, a scatter plot is drawn. Multiple spline curves are used to fit the scatter plots to establish an empirical formula characterizing the relationship between the pressure of the high-pressure vortex jet and time.

[0093] S16 Analysis of Evolution Laws: Data collected by the high-speed camera 5-5 during the experiment was processed to obtain the development and evolution of the soil displacement field and the distribution law of the high-pressure vortex jet flow field. The specific method is as follows: The soil displacement field data was imported into PIVlab and Tecplot software to plot the soil displacement and high-pressure vortex jet flow field contour maps at multiple different times (10s, 20s, 30s, 40s, and 50s) after reaching the predetermined initial pressure of the high-pressure vortex jet. The box-counting method was used to calculate the fractal dimension values ​​of the soil displacement contour lines and the high-pressure vortex jet flow field contour lines at different times.

[0094] Example

[0095] This method is used to conduct a visualization experiment on the interaction between high-pressure vortex jet and coastal soft soil under the conditions of high-pressure vortex jet pressure of 2 MPa and overlying soil pressure of 50 kPa. The specific steps are as follows:

[0096] On-site sampling: Coastal soft soil samples were taken at a vehicle depot construction site in a coastal area in accordance with the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019).

[0097] Liquid limit determination: The liquid limit of soft soil was determined using a combined liquid and plastic limit tester; Indoor drying: The collected coastal soft soil samples were placed in batches in a 4-8KW oven for drying. The drying temperature was set to 105℃ and the drying time was 24h. The dried soft soil test blocks were obtained.

[0098] Powder preparation: The dried coastal soft soil test blocks were initially crushed manually, and then the crushed soft soil test blocks were further crushed using a pulverizer to obtain coastal soft soil powder;

[0099] Selecting the optimal moisture content for soft soil powder: Five groups of indoor saturated quick-shear samples with different moisture contents were prepared from the soft soil powder. The five moisture contents were 1.1, 1.3, 1.5, 1.7, and 1.9 times the liquid limit, respectively. Indoor saturated quick-shear tests were conducted to obtain the optimal moisture content corresponding to the maximum fluidity. Soft soil saturation: Coastal soft soil powder and water with the optimal moisture content were added to a mixer simultaneously and vacuum-mixed for 2 hours to obtain the fluid saturated soft soil required for the model test. Assembly of the detachable model box: The bottom panel 1-1, left panel 1-2, right panel 1-3, front panel 1-4, and rear panel 1-5 were connected together to complete the assembly of the detachable model box 1.

[0100] Tracer system installation: Nano-coating material 6-1, Vaseline 6-2, and thin-layer fine sand tracer particles 6-3 are uniformly applied to the inner wall of the front panel 1-4 of the detachable model box 1.

[0101] Backfilling and installation of measuring frame: The prepared saturated coastal soft soil is filled into the detachable model box 1 in layers until the surface of the filled soil reaches the predetermined installation position of the measuring frame 5-2 and then the backfilling is stopped; the measuring frame 5-2 is installed at the predetermined positions on the left panel 1-2 and right panel 1-3 of the detachable model box 1, specifically at 3 / 4 of the distance from the bottom panel.

[0102] Piezoresistive pressure sensor installation: Fix piezoresistive pressure sensors 5-3 at equal intervals along the axis of the measuring frame 5-2, adjust the height of the piezoresistive pressure sensors 5-3 so that they are at the same height as the through hole 1-2-1 reserved on the left panel 1-2 of the detachable model box 1; connect the other end of the wiring of the piezoresistive pressure sensor 5-3 to the strain gauge 5-1.

[0103] Filling with excess soil: Continue to fill the prepared saturated coastal soft soil into the detachable model box 1 in layers until the surface of the filled soil is slightly lower than the top of the detachable model box 1, and then the filling is completed.

[0104] Installation of the overburden pressure simulation system: Place the loading plate 4-3 on the fill surface, and then install the jack 4-4, force transmission beam 4-2, and reaction frame 4-1 in sequence. Fix the reaction frame 4-1 to the force transmission beam 4-2, and fix the force transmission beam 4-2 to the left panel 1-2 and right panel 1-3 of the detachable model box 1 to complete the installation of the overburden pressure simulation system 4.

[0105] Installation of the high-pressure vortex jet generation system: Based on the three technical parameters of the high-pressure nozzle required for the experiment, namely the nozzle diameter (5mm), linear aspect ratio (5), and narrow angle (13°), a nozzle structure adjuster 3-5-2 was fabricated using transparent photosensitive resin material and embedded into the high-pressure nozzle 3-5. The high-pressure nozzle 3-5 was inserted into the pre-drilled through hole 1-2-1 on the left panel 1-2 of the detachable model box 1 and fixed. The left end of the high-pressure nozzle 3-5 was connected to the second explosion-proof pipe 3-4. A pressure gauge 3-6 and an electromagnetic flowmeter 3-7 were installed on the second explosion-proof pipe 3-4. Then, the high-pressure pump 3-2, the first explosion-proof pipe 3-4, and the solution storage tank 3-1 were installed in sequence to complete the installation of the high-pressure vortex jet generation system 3.

[0106] Preparation of the jet medium simulation system: Add pure water 2-1 to the solution storage tank 3-1 until it is close to the top height, then add sodium polyacrylate 2-2 with a mass fraction of 0.2%; then add phosphor particles 2-3 with a diameter of 6μm and a mass concentration of 0.1g / ml, stir evenly, and the jet medium simulation system 2 is prepared.

[0107] High-speed camera installation and calibration: The high-speed camera 5-5 is fixed to the front of the front panel 1-4 of the detachable model box 1 using a tripod 5-5-1, and LED light sources 5-4 are arranged around it to ensure that the light sources are stably focused on the front panel 1-4 of the detachable model box 1, so as to ensure the quality of the acquired digital images; the high-speed camera 5-5 connected to the computer 5-7 is calibrated using a camera calibration plate 5-6, and the analysis error caused by the geometric distortion of the captured images is corrected.

[0108] Pulsating laser placement: A first pulsed laser 5-8 and a second pulsed laser 5-9 are respectively placed in front of the front panel 1-4 and right panel 1-3 of the detachable model box 1. The orientation is adjusted so that the pulsed laser beams emitted by the first pulsed laser 5-8 and the second pulsed laser 5-9 are perpendicular to and parallel to the front panel 1-4 of the detachable model box 1, respectively.

[0109] Applying overburden pressure load: Use jack 4-4 to steadily apply pressure to the reaction frame 4-1 in the overburden pressure simulation system 4 until the pressure value of the loading plate 4-3 acting on the saturated coastal soft soil surface reaches the predetermined value of 50 kPa.

[0110] Start the system to begin the test: Connect the power supply to the high-pressure pump 3-2, set the pressure of the high-pressure vortex jet 3-5-1 to 2MPa, turn on the strain gauge 5-1, high-speed camera 5-5, LED light source 5-4, first pulsed laser 5-8, second pulsed laser 5-9 and computer 5-7, and begin the visualization model test of the interaction between the high-pressure vortex jet and coastal soft soil under the conditions of a high-pressure vortex jet pressure of 2MPa and an overlying soil pressure of 50kPa. During the test, data such as the pressure decay law of the high-pressure vortex jet and the development and evolution law of the soil displacement field are collected and recorded in real time, and the growth of the distance that the high-pressure vortex jet cuts the soil is observed.

[0111] Shutdown and cleaning: When the distance of the high-pressure vortex jet cutting the soil remains basically stable, turn off the power of the high-pressure pump 3-2, stop the model test, remove the overlying soil pressure simulation system 4, excavate the coastal soft soil inside the detachable model box 1, clean the detachable model box 1, and analyze the test data.

[0112] A quantitative model was established: Data collected by piezoresistive pressure sensors during the experiment was analyzed and processed to obtain experimental data on the attenuation law of high-pressure swirling jet pressure with distance and time. The data processing method for the attenuation law of high-pressure swirling jet pressure with distance is as follows: A scatter plot was drawn with the horizontal distance between the piezoresistive pressure sensor and the high-pressure nozzle as the x-axis, and the pressure collected by different piezoresistive pressure sensors at 10s, 20s, 30s, 40s, and 50s after reaching the predetermined initial pressure value of the high-pressure swirling jet as the y-axis. Multiple spline curves were used to fit the scatter plots to establish an empirical formula characterizing the relationship between high-pressure swirling jet pressure and distance. The data processing method for the attenuation law of high-pressure swirling jet pressure with time is as follows: A scatter plot was drawn with the pressure collected by piezoresistive pressure sensors at different distances from the high-pressure nozzle at 10s, 20s, 30s, 40s, and 50s after reaching 2MPa as the x-axis, and the pressure collected by piezoresistive pressure sensors at different distances from the high-pressure nozzle as the y-axis. Multiple spline curves were used to fit the scatter plots to establish an empirical formula characterizing the relationship between high-pressure swirling jet pressure and time.

[0113] Analysis of Evolution Laws: Data collected by high-speed cameras during the experiment were processed to obtain the development and evolution of the soil displacement field and the distribution law of the high-pressure vortex jet flow field. The specific method is as follows: The soil displacement field data was imported into PIVlab and Tecplot software to plot the soil displacement contour maps at 10s, 20s, 30s, 40s, and 50s after reaching 2MPa. The box-ring method was used to calculate the fractal dimension values ​​of the soil displacement contour maps and the high-pressure vortex jet flow field contour maps at different times.

[0114] It should be noted that any technical features not described in detail in this invention can be implemented using any existing technology.

[0115] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

Claims

1. A high-pressure rotary jet flow and soft soil interaction visualization test device, characterized in that, The detachable model box, the jet medium simulation system, the high-pressure rotary jet generation system, the overburden pressure simulation system, a data acquisition system and a tracer system are included. The detachable model box comprises a bottom panel, a left panel, a right panel, a front panel and a rear panel, the bottom panel, the left panel and the right panel are connected in an integral welding manner, the front panel and the rear panel are made of transparent tempered glass, and the front panel and the rear panel are connected with the bottom panel, the left panel and the right panel through bolts. The high-pressure rotary jet generation system comprises a solution storage tank, a high-pressure pump, a first explosion-proof pipe, a second explosion-proof pipe, a high-pressure nozzle, a nozzle structure regulator, a pressure gauge and an electromagnetic flowmeter. The high-pressure pump is used to pressurize the jet medium simulation system to a predetermined high-pressure rotary jet injection pressure. The jet medium simulation system comprises pure water, sodium polyacrylate and fluorescent powder particles. The overburden pressure simulation system comprises a counterforce frame, a force transmission beam, a loading plate and a jack. The data acquisition system comprises a measurement frame, a piezoresistive pressure sensor, a first pulsating laser and a second pulsating laser. The tracer system comprises nano-coated materials, vaseline and thin-layer fine sand tracer particles. The soft soil required for the test is saturated soft soil with fluidity, and the method for preparing the saturated soft soil with fluidity is as follows: (1) sampling from an engineering site in a soft soil area; (2) The liquid limit value of the soft soil is measured by using a liquid-plastic limit combined tester; (3) The retrieved soft soil sample is placed in batches in a 4-8KW power oven for drying, the drying temperature is set to 100-120 DEG C, and the drying time is 24 hours, so as to obtain the dried soft soil test block; (4) The dried soft soil test block is initially knocked and then further crushed by using a crusher to obtain the soft soil powder; (5) The soft soil powder is prepared into five groups of indoor saturated quick shear samples with different water contents, indoor saturated quick shear tests are carried out, and the most suitable water content corresponding to the maximum fluidity is obtained; (6) The soft soil powder and water with the most suitable water content are simultaneously added into a mixer, vacuum stirring is carried out for 2 hours, and the saturated soft soil with fluidity required by the model test is obtained.

2. The high-pressure rotary jet flow and soft soil interaction visualization test device according to claim 1, characterized in that, The gaps between the front panel, the back panel, the bottom panel, the left panel and the right panel are filled with waterproof foam to prevent the high-pressure rotary jet flow from flowing out of the gaps.

3. The device for visualizing the interaction of a high-pressure rotational jet with soft soil according to claim 1, characterized in that The length and height of the detachable model box are 8-10 times of the width.

4. The device for visualizing the interaction of a high-pressure rotational jet with soft soil according to claim 1, characterized in that The thickness of the front panel and the back panel is not less than 3 cm.

5. The device for visualizing the interaction of a high-pressure rotational jet with soft soil according to claim 1, characterized in that The preparation process of the jet medium simulation system is as follows: pure water is added to the solution storage tank to near the top, and 0.1%-0.3% sodium polyacrylate is added; then, 5-8 μm diameter fluorescent powder particles with a mass concentration of 0.1 g / ml are added and stirred uniformly.

6. The device for visualizing the interaction of a high-pressure rotational jet with soft soil according to claim 1, characterized in that The height of the piezoresistive pressure sensor is kept at the same height as the through hole on the left panel of the detachable model box.

7. The device for visualizing the interaction of a high-pressure rotational jet with soft soil according to claim 1, characterized in that The piezoresistive pressure sensors are arranged at equal intervals along the direction parallel to the axis of the high-pressure rotary jet flow, and the positions are slightly deviated from the axis of the high-pressure rotary jet flow on the horizontal plane.

8. A method for visualizing the interaction of a high-pressure rotary jet with soft soil, characterized in that The method is suitable for the visualization test device for the interaction between the high-pressure rotary jet flow and the soft soil according to any one of claims 1-7, and the test method comprises: Preparation of the saturated soft soil with fluidity: (1) Sampling from the engineering site in the soft soil area; (2) Measuring the liquid limit value of the soft soil by using a liquid-plastic limit combined tester; (3) Placing the retrieved soft soil sample in batches in a 4-8KW power oven for drying, setting the drying temperature to 100-120 DEG C, and drying for 24 hours to obtain the dried soft soil test block; (4) Initially knocking the dried soft soil test block and then further crushing the initially knocked soft soil test block by using a crusher to obtain the soft soil powder; (5) Preparing the soft soil powder into five groups of indoor saturated quick shear samples with different water contents, carrying out indoor saturated quick shear tests, and obtaining the most suitable water content corresponding to the maximum fluidity; (6) Simultaneously adding the soft soil powder and water with the most suitable water content into a mixer, vacuum stirring for 2 hours, obtaining the saturated soft soil with fluidity required by the model test, and setting the drying temperature to 100-120 DEG C; Assembling the detachable model box: connecting the bottom panel, the left panel, the right panel, the front panel and the back panel together; Tracing system laying: uniformly applying nano-coated film material, vaseline and thin-layer fine sand tracer particles on the inner wall of the front panel of the detachable model box in sequence; Soil filling and installation of measuring frame: The prepared saturated soft soil is filled in the detachable model box layer by layer until the surface of the filled soil reaches the predetermined installation position of the measuring frame, and the soil filling is paused; the measuring frame is installed at the predetermined position of the left panel and the right panel of the detachable model box; Installation of piezoresistive pressure sensor: The piezoresistive pressure sensor is fixed on the measuring frame at equal intervals along the axial direction, and the height of the piezoresistive pressure sensor is adjusted to be at the same height as the through hole reserved on the left panel of the detachable model box; the other end of the wire of the piezoresistive pressure sensor is connected to the strain gauge; Remaining soil filling: The prepared saturated soft soil is continuously filled in the detachable model box layer by layer until the surface of the filled soil is slightly lower than the top position of the detachable model box, and the soil filling is completed; Installation of overburden pressure simulation system: The loading plate is placed on the surface of the filled soil, and then the jack, the force transmission beam and the reaction frame are installed in sequence, the reaction frame is fixed on the force transmission beam, the force transmission beam is fixed on the left panel and the right panel of the detachable model box, and the installation of the overburden pressure simulation system is completed; Installation of high-pressure rotary jet flow generation system: The nozzle structure regulator matching the internal size of the high-pressure nozzle is made by 3D printing with transparent photosensitive resin material, and the nozzle structure regulator is embedded in the high-pressure nozzle; the high-pressure nozzle is inserted into the through hole reserved on the left panel of the detachable model box and fixed; the left end of the high-pressure nozzle is connected to the second explosion-proof pipe, and the pressure gauge and the electromagnetic flowmeter are installed on the second explosion-proof pipe; then the high-pressure pump, the first explosion-proof pipe and the solution storage tank are installed in sequence, and the installation of the high-pressure rotary jet flow generation system is completed; Preparation of jet medium simulation system: Pure water is added to the solution storage tank to near the top height, then 0.2% sodium polyacrylate is added; then 6μm diameter, 0.1g / ml mass concentration of fluorescent powder particles are added and stirred uniformly to prepare the jet medium simulation system; Installation and calibration of high-speed camera: The high-speed camera is fixed in front of the front panel of the detachable model box through a tripod, and LED light sources are arranged around it to ensure that the light sources are stably focused on the front panel of the detachable model box to ensure the quality of the digital images collected; the high-speed camera connected to the computer is calibrated using a camera calibration board, and the analysis error caused by geometric distortion of the photographed pictures is corrected; Pulsed laser arrangement: The first pulsed laser and the second pulsed laser are arranged in front of the front panel and the right panel of the detachable model box respectively, and the orientation is adjusted so that the pulsed laser beams emitted by the first pulsed laser and the second pulsed laser are perpendicular and parallel to the front panel of the detachable model box respectively; Application of overburden pressure load: The jack is used to stably apply pressure to the reaction frame in the overburden pressure simulation system until the pressure value of the loading plate acting on the surface of the saturated soft soil reaches the predetermined value. The starting device starts the test: turn on the high-pressure pump power supply, set the pressure value of the high-pressure jet, open the strain gauge, high-speed camera, LED light source, first pulsating laser, second pulsating laser, and computer, and perform the visual model test of the interaction between the high-pressure jet and saturated soft soil under the condition that the high-pressure jet pressure is the set pressure value of the high-pressure jet and the overburden pressure is a predetermined value. In the test process, real-time collection and recording of data such as the pressure decay law of the high-pressure jet and the development and evolution law of the soil displacement field are performed, and the growth of the distance at which the high-pressure jet cuts the soil is observed. Shutdown and cleaning: when the distance at which the high-pressure jet cuts the soil basically remains stable, the high-pressure pump power supply is turned off, the model test is stopped, the overburden pressure simulation system is removed, the saturated soft soil inside the detachable model box is dug out, the detachable model box is cleaned, and the test data are analyzed. Establishing a quantitative model: the data collected by the piezoresistive pressure sensor in the test process are analyzed and processed to obtain the test data of the decay law of the high-pressure jet pressure with distance and time. Analyzing the evolution law: the data collected by the high-speed camera in the test process are processed to obtain the development and evolution of the soil displacement field and the distribution law of the high-pressure jet flow field.

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