Sandy gravel stratum grouting simulation test system and method based on three-dimensional forming technology

Abstract

The invention provides a sand-gravel stratum grouting simulation test system and method based on a three-dimensional forming technology, and relates to the technical field of grouting simulation tests.The sand-gravel stratum simulation module identifies an underground geologic structure and a stratum interface of a sand-gravel stratum to be simulated based on drilling geophysical prospecting data and geological prospecting information; obtaining stratum interface refined characterization, stratum permeability attribute characterization and stratum water-rich degree attribute characterization; on the basis of refined representation of stratum interfaces, three-dimensional forming printing is conducted on the stratum interfaces, the stratum interfaces are fixed in a test model cylinder, stratum media are filled layer by layer according to stratum permeability attribute representation and stratum water-rich degree attribute representation, and construction of a sandy gravel stratum model is completed; based on the structural analysis of the to-be-simulated sandy gravel stratum, the stratum interface and the filling medium are printed through the three-dimensional forming technology, the sandy gravel stratum model is constructed, and the reliability and accuracy of a sandy gravel stratum grouting simulation test are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of grouting simulation test, and in particular relates to a sand and gravel stratum grouting simulation test system and method based on three-dimensional molding technology. Background Art

[0002] In the current tunnel construction, water damage has become a prominent problem, which not only seriously affects the quality and progress of the project, but also may cause a significant increase in project costs and even lead to serious engineering safety accidents. In order to effectively meet this challenge, grouting technology is widely used in water damage prevention and control in tunnel construction. By injecting slurry into the ground and utilizing its transformation process from liquid to solid, it can effectively block the water flow channel and reinforce the stratum, thereby ensuring the safety and reliability of tunnel construction.

[0003] However, due to the complexity and variability of the geological environment, the geological conditions in different regions have different requirements for grouting technology. Sand and gravel strata are a common geological structure in river alluvial plains and piedmont alluvial fans. They are composed of pebbles and sandstones of different sizes. The particle sizes of the stratum components vary greatly, the structure is loose, and it has complex and changeable permeability and physical and mechanical behavior. In addition, the disturbance caused by groundwater recharge and construction activities has brought a series of engineering construction challenges to grouting management.

[0004] At present, the main methods for studying the grouting mechanism of gravel formations are numerical simulation and grouting test. The application of numerical simulation methods is limited by the relevant theories and numerical calculations that are still in the development stage. For grouting tests, the existing test models are often difficult to accurately restore the changes in parameters such as different depths, thicknesses and formations in actual projects, and cannot effectively meet the needs of large-scale formation restoration, and cannot monitor and finely analyze the three-dimensional process of slurry diffusion in real time, especially in the characterization of formation interfaces. The accurate characterization of formation interfaces has a great influence on the exploration of grouting mechanisms in gravel formations, but the existing technology mainly relies on a single drilling or geophysical exploration method, which cannot accurately identify the interface characteristics in complex formations and is difficult to meet the refined requirements of complex formation interface characteristics in engineering projects. In terms of filling the medium of gravel formations, the existing filling methods are difficult to accurately simulate the pore structure, particle grading and permeability of the in-situ soil, resulting in obvious differences between the test model and the actual formation conditions; therefore, the existing simulation test technology for grouting in gravel formations has defects, which affects the reliability and accuracy of the grouting test results. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a sand and gravel formation grouting simulation test system and method based on three-dimensional molding technology. Based on the structural analysis of the sand and gravel formation to be simulated, the formation interface and filling medium are printed by three-dimensional molding technology to construct a sand and gravel formation model, thereby improving the reliability and accuracy of the sand and gravel formation grouting simulation test.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present invention provides a sand and gravel formation grouting simulation test system based on three-dimensional molding technology.

[0008] The sand-pebble formation grouting simulation test system based on three-dimensional molding technology includes a sand-pebble formation simulation module for constructing a sand-pebble formation model and an anti-segregation double-liquid grouting module for grouting into the sand-pebble formation model;

[0009] The sand and gravel formation simulation module identifies the underground geological structure and formation interface of the sand and gravel formation to be simulated based on drilling geophysical data and geological exploration information, and obtains a refined representation of the formation interface, a representation of the formation permeability attribute, and a representation of the formation water-rich degree attribute. Based on the refined representation of the formation interface, each formation interface is three-dimensionally printed and fixed in a test model cylinder, and according to the representation of the formation permeability attribute and the representation of the formation water-rich degree attribute, the formation medium is filled layer by layer to complete the construction of the sand and gravel formation model.

[0010] Furthermore, the identification of the underground geological structure and the stratum interface of the sandy gravel stratum to be simulated obtains a refined representation of the stratum interface, a representation of the stratum permeability attribute, and a representation of the stratum water-richness attribute, specifically:

[0011] By drilling and coring the simulated sand and gravel strata, the porosity and permeability of the strata at different depths are analyzed, and the characteristic points of the interface are determined according to the strata attribute differences and attribute difference thresholds within different height ranges, so as to form a preliminary fitting strata interface.

[0012] Based on the analysis of seismic wave signals, the underground geological structure and stratigraphic interfaces are identified based on the preliminary fitted stratigraphic interfaces, and the stratigraphic types, porosity, permeability and water-richness of the optimized stratigraphic interfaces and between the stratigraphic interfaces are obtained.

[0013] Furthermore, the three-dimensional printing of the interfaces of various layers is specifically as follows:

[0014] Based on the optimized interfaces of each stratum, the stratum skeleton is digitally modeled through 3D modeling technology, and the stratum interfaces in the model are three-dimensionally printed.

[0015] Furthermore, the test model cylinder is assembled from a plurality of different stratigraphic units from bottom to top, and the stratigraphic units are divided by stratigraphic interfaces;

[0016] The inner wall of the cylinder is made of a high-pressure-resistant silicone composite material with a gel inner ring. The inner ring is provided with closely arranged sliding grooves to accurately fix and adjust the position of the three-dimensionally formed stratum interface.

[0017] A stereoscopic observation window made of high-strength transparent material is provided on the test model cylinder to observe the three-dimensional local diffusion and flow of the slurry during the grouting process.

[0018] Furthermore, the fixing in the test model cylinder is based on the relative heights of the various stratum interfaces, and the printed stratum interfaces are embedded in the slidable grooves of the test model cylinder.

[0019] Furthermore, the filling of the formation medium layer by layer is carried out by selecting the filling medium to fill the formation units between each interface according to the formation type, porosity, permeability and water richness between each interface of the sand and gravel formation.

[0020] Furthermore, the filling medium includes two types:

[0021] Using in-situ formation media of the sand-pebble formation to be simulated;

[0022] The formation medium is printed using 3D printing technology based on porosity, permeability and water richness.

[0023] Furthermore, the anti-segregation dual-liquid grouting module includes two constant-speed dual-liquid piston grouting pumps, a grout storage tank and a grouting pipeline;

[0024] The bottom of the constant speed dual-liquid piston grouting pump is provided with a sonic vibration device and a pressurized air nozzle. When the cement slurry enters the slurry storage tank, the sonic vibration device and the pressurized air nozzle are started synchronously to ensure that the cement slurry always maintains uniform distribution and stability during the grouting process.

[0025] Furthermore, it also includes an information collection module and a data analysis module;

[0026] The information acquisition module uses sensors to collect data during the grouting process;

[0027] The data analysis module analyzes the data collected by the sensor.

[0028] The second aspect of the present invention provides a sand and gravel formation grouting simulation test method based on three-dimensional molding technology.

[0029] The sand and gravel stratum grouting simulation test method based on three-dimensional molding technology includes:

[0030] Based on the drilling geophysical data and geological exploration information, the underground geological structure and stratigraphic interface of the sand and gravel strata to be simulated are identified, and the refined representation of the stratigraphic interface, the stratigraphic permeability attribute representation and the stratigraphic water-rich degree attribute representation are obtained; based on the refined representation of the stratigraphic interface, each stratigraphic interface is three-dimensionally printed and fixed in the test model cylinder, and according to the stratigraphic permeability attribute representation and the stratigraphic water-rich degree attribute representation, the stratigraphic medium is filled layer by layer to complete the construction of the sand and gravel strata model;

[0031] Grouting was injected into the constructed sand-pebble stratum model to conduct a grouting simulation test of the sand-pebble stratum.

[0032] The third aspect of the present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps in the sand and gravel formation grouting simulation test system based on three-dimensional molding technology as described in the first aspect of the present invention.

[0033] The fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps in the sand and gravel formation grouting simulation test system based on three-dimensional molding technology as described in the first aspect of the present invention are implemented.

[0034] One or more of the above technical solutions have the following beneficial effects:

[0035] (1) The present invention realizes large-scale restoration and fine characterization of sand and gravel formation conditions of different engineering scales, such as different depths, formation thicknesses, formation types, water-richness, and permeability properties, by providing height-adjustable formation units and unit height adjustment mechanisms at different heights of the sand and gravel formation model; one quarter of the sand and gravel formation model is set as a stereoscopic observation window made of high-strength transparent material, and is equipped with scales and marks to realize three-dimensional local intuitive visualization of the slurry during the grouting process.

[0036] (2) The present invention proposes a method for finely characterizing the interface between sand and gravel strata based on the combination of drilling and geophysical exploration. The method comprises: coring the target area by drilling, analyzing the porosity and permeability of the strata at different depths, and determining the characteristic points of the interface based on the comparison between the strata attribute differences within different height ranges and the attribute difference thresholds, thereby forming a preliminary fitting strata interface. Based on the analysis of seismic wave signals, the underground geological structure and strata interface are identified. Taking the primary interface as a reference, the interface fitted by the drilling method is optimized and adjusted using the data processing results, thereby achieving accurate characterization and restoration of the strata porosity, permeability and water richness between the strata interfaces.

[0037] (3) The present invention proposes an in-situ sand and gravel formation medium filling method based on three-dimensional molding technology. The formation microstructure is obtained through microscopy and CT scanning, the pore structure model is digitally established, and the printing parameters (such as interface thickness, material, etc.) are precisely controlled to achieve high-precision formation structure reproduction, significantly improve the accuracy and controllability in sand and gravel formation experiments, and ensure the reliability of the experimental results.

[0038] (4) The dual-liquid grouting pump used in the present invention is provided with a sonic vibration device and a pressurized air nozzle at the bottom. When the cement slurry enters the slurry storage tank, the sonic vibration device and the pressurized air nozzle are started synchronously to ensure that the cement slurry always maintains uniform distribution and stability during the grouting process, reduce the segregation of the cement slurry due to the time effect, and avoid the occurrence of problems such as uneven strength and reduced durability of cement stone in the injected area.

[0039] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0041] Figure 1 It is a structural diagram of the sand and gravel formation grouting simulation test system of the first embodiment.

[0042] Figure 2 This is a structural diagram of the anti-segregation double-liquid grouting module of the first embodiment.

[0043] Figure 3 This is a method flow chart of the second embodiment.

[0044] Among them, 1. Information acquisition module; 2. Information acquisition cable; 3. Stereoscopic observation window; 4. Upper bottom plate of the cylinder; 5. Grouting hole; 6. Formation unit; 7. Flow meter; 8. Constant speed double-liquid piston grouting pump; 10. Slurry pipeline; 11. Slurry preparation tank; 13. Image acquisition unit; 14. Slurry storage tank; 15. Data analysis module; 16. Grouting pipeline; 17. Acoustic vibration device. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] Embodiment 1

[0048] In one embodiment of the present disclosure, a sand and gravel formation grouting simulation test system based on three-dimensional molding technology is provided. Figure 1 As shown, it includes a sand and gravel formation simulation module, an anti-segregation double-liquid grouting module, an information acquisition module and a data analysis module, which are described in detail below.

[0049] 1. Sand and gravel formation simulation module

[0050] The invention is used for constructing a sand-pebble stratum model, and comprises a test model cylinder, a stratum structure analysis unit, a stratum interface three-dimensional molding unit, and a stratum setting unit.

[0051] 1. Test model cylinder

[0052] The cylinder is assembled from multiple different stratum units 6 from bottom to top, and the stratum units are divided by stratum interfaces. The inner wall of the cylinder adopts a gel inner ring made of high-pressure resistant silicone composite material to ensure stability and durability under high-pressure conditions.

[0053] The inner ring is provided with closely arranged sliding grooves for accurately fixing and adjusting the position of the three-dimensionally formed stratum interface.

[0054] The stratum interface is precisely positioned three-dimensionally by adjusting the height of the groove according to the stratum position relationship obtained by the stratum structure analysis unit, and is placed and fixed at the corresponding position of the test model.

[0055] A stereoscopic observation window 3 made of high-strength transparent material is provided on the test model cylinder for observing the three-dimensional local diffusion and flow of the slurry during the grouting process. In the present embodiment, one quarter of the outer surface of the cylinder is made of high-strength transparent material to form a stereoscopic observation window 3, which is equipped with precise scales and markings to facilitate intuitive visualization of the three-dimensional local diffusion and flow of the slurry during the grouting process.

[0056] 2. Stratigraphic structural analysis unit

[0057] Based on drilling geophysical data and geological exploration information, the underground geological structure and stratigraphic interface of the sand and gravel stratum to be simulated are identified, and the refined characterization of the stratigraphic interface, the characterization of the stratigraphic permeability properties and the characterization data of the stratigraphic water-richness properties are obtained.

[0058] The fine characterization of the formation interface here includes data such as the position and shape of the interface, medium type, etc. The characterization of the formation permeability attributes includes data such as porosity, pore structure and distribution, and the characterization of the formation water-richness attributes includes data such as water-richness, water saturation, and dynamic water flow rate. The specific process is as follows:

[0059] Drilling and coring were carried out on the simulated sand and gravel strata to analyze the depths of different strata and the relative depths between strata, and the medium type, permeability, porosity, pore structure and distribution of strata at different depths were obtained.

[0060] According to the difference of stratum attributes within each stratum depth range and the set attribute difference threshold, the height exceeding the threshold is determined as the characteristic point of the stratum interface.

[0061] Through surface surveys and geological survey reports, drilling sites that potentially contain key stratigraphic interfaces are selected as drilling locations, and multiple feature points are obtained. The preliminary stratigraphic interfaces are preliminarily fitted, and the porosity, permeability, water richness and other data between the interfaces are recorded. The water richness, water saturation and dynamic water flow rate inside the formation are inferred based on the water output of all boreholes.

[0062] Vibrations are stimulated in the target stratum area, and the seismic recorder records the signals of the seismic waves reflected underground and returning to the surface. The existing technologies are used to sequentially perform data cleaning, dynamic and static correction, velocity analysis, residual static correction, profile stacking and migration, inversion analysis, and stratum interface identification on the seismic signals to obtain images or numerical data such as depth profiles, seismic reflection profiles, velocity models, and three-dimensional geological models.

[0063] According to the processing results, the underground geological structure and stratigraphic interface are comprehensively analyzed and evaluated to obtain the position and shape of the stratigraphic interface, identify the underground geological structure and stratigraphic interface, and optimize and adjust it based on the preliminary interface to achieve accurate capture and identification of each stratigraphic interface.

[0064] 3. Three-dimensional modeling unit of stratum interface

[0065] The stratum skeleton is digitally modeled through 3D modeling technology. The model size is scaled according to the actual stratum. The model is layered (i.e., the strata are divided and the interfaces are arranged at different stratum heights). The printing path of each layer is generated, and the printing parameters are set during the slicing process, including the printing material and printing speed set according to the permeability and porosity of the strata above and below the interface. The 3D molding machine is further prepared to ensure the cleanliness of the print bed and level it as needed. The appropriate printing material is loaded and the sliced ​​file is uploaded to the 3D molding machine to complete the printing of the stratum interface.

[0066] 4. Strata Setting Unit

[0067] According to the scale ratio of the actual stratum, the relative height of each stratum interface is determined, and the three-dimensional stratum interface is accurately embedded in the slidable groove on the inner ring of the gelatin. After the stratum interface is fixed, the sand and gravel are filled layer by layer according to the parameters such as the stratum type, porosity, permeability and water richness between the interfaces of the sand and gravel stratum, and finally the sand and gravel stratum model is constructed.

[0068] The filling medium can be arranged and filled with the in-situ sand and gravel stratum medium of the area to be simulated. If the clay content of the in-situ stratum is high and it is difficult to ensure the properties of the in-situ soil during the arrangement process, the stratum medium is printed using 3D printing technology. The specific steps are as follows:

[0069] The simulated strata are scanned under a microscope and CT scans to obtain the microstructure images and stratum structures of the natural strata, which are digitized to establish an accurate pore structure model; the settings include printing material and printing speed according to the permeability and porosity of the strata, and further preparation of the 3D modeling machine to ensure the cleanliness of the print bed, and level it as needed, load the printing material, upload the sliced ​​file to the 3D modeling machine, complete the printing of the 3D medium model, and arrange the strata on the printed model.

[0070] 2. Anti-segregation double liquid grouting module

[0071] Used for grouting into constructed sand and gravel formation models, such as Figure 2 As shown, it includes two constant speed dual-liquid piston grouting pumps 8, a grout storage tank 14 and a grouting pipeline 16.

[0072] Specifically, the top of the grouting pump 8 is connected to a slurry delivery pipeline 10, and the prepared slurry in the slurry preparation tank 11 can be transmitted to the slurry storage tank 14 of the grouting pump 8 through this pipeline. The grouting pump slurry storage tank 14 is used to store the slurry before the start of the test. The upper part of the slurry storage tank 14 is a piston-type grouting pump 8; the suction of the piston provides power for the slurry injection, ensuring that the slurry is smoothly injected into the grouting holes 5 of the sand and gravel formation model; the grouting pipeline 16 adopts a transparent hose to ensure a certain pressure bearing capacity and visibility.

[0073] The grouting pump 8 is provided with an acoustic vibration device 17 and a pressurized air nozzle in the grouting tank 14, which are evenly arranged at the bottom and around the tank. When the cement slurry enters the grouting tank 14, the acoustic vibration device 17 and the pressurized air nozzle are started synchronously to ensure that the cement slurry always maintains uniform distribution and stability during the grouting process. Through the start and stop of each function of the anti-segregation dual-liquid grouting module and the gear adjustment, accurate control during the grouting process is ensured, and finally efficient and accurate grouting is achieved throughout the entire experimental process.

[0074] 3. Information Collection Module 1

[0075] Sensors are used to collect data during the grouting process, including pressure sensors, soil pressure boxes, seepage pressure sensors, and temperature sensors.

[0076] Soil pressure cell: arranged around the inner wall of the test model cylinder and inside the upper bottom plate 4, used to monitor the pressure changes inside the model;

[0077] Seepage pressure sensor: buried in the sand and gravel formation, used to monitor the pore water pressure inside the medium in real time;

[0078] It also includes an image acquisition unit 13, which acquires a local slurry penetration image sequence in the formation based on the stereoscopic observation window 3 through a camera arranged at the test model cylinder.

[0079] The above-mentioned collected data are all transmitted to the data analysis module 1 in real time through the information collection cable 2, so as to reveal the diffusion mechanism of the grouting slurry in the sand and gravel formation.

[0080] 4. Data Analysis Module 15

[0081] The data collected by the sensor are analyzed, including a pressure analysis unit and a slurry diffusion analysis unit.

[0082] Pressure analysis unit: Based on the pressure data collected by pressure sensors, soil pressure boxes, and seepage pressure sensors, the soil pressure, grouting pressure, and pore water pressure of the formation grouting process are analyzed, and the change law of the grouting pressure at the orifice mixing position and the change law of the confining pressure and seepage pressure inside the medium are analyzed;

[0083] Grout diffusion analysis unit: Based on the stereoscopic observation window, the local grout penetration image sequence in the stratum is obtained, and the grout vein distribution is revealed by excavation to reveal the suitable pressure range and grout diffusion form for grouting and plugging in sandy and gravel strata under the influence of different porosity, permeability and water richness.

[0084] Embodiment 2

[0085] In one embodiment of the present disclosure, a sand and gravel formation grouting simulation test method based on three-dimensional molding technology is provided. Figure 3 As shown, including:

[0086] Based on the drilling geophysical data and geological exploration information, the underground geological structure and stratigraphic interface of the sand and gravel strata to be simulated are identified, and the refined representation of the stratigraphic interface, the stratigraphic permeability attribute representation and the stratigraphic water-rich degree attribute representation are obtained; based on the refined representation of the stratigraphic interface, each stratigraphic interface is three-dimensionally printed and fixed in the test model cylinder, and according to the stratigraphic permeability attribute representation and the stratigraphic water-rich degree attribute representation, the stratigraphic medium is filled layer by layer to complete the construction of the sand and gravel strata model;

[0087] Grouting was injected into the constructed sand-pebble stratum model to conduct a grouting simulation test of the sand-pebble stratum.

[0088] Embodiment 3

[0089] The purpose of this embodiment is to provide a computer-readable storage medium.

[0090] A computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps in the sand and gravel formation grouting simulation test system based on three-dimensional molding technology as described in the first embodiment of the present disclosure.

[0091] Embodiment 4

[0092] The purpose of this embodiment is to provide an electronic device.

[0093] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps in the sand and gravel formation grouting simulation test system based on three-dimensional molding technology as described in the first embodiment of the present disclosure are implemented.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology is characterized by: It includes a sand-pebble formation simulation module for constructing a sand-pebble formation model and an anti-segregation double-liquid grouting module for grouting into the sand-pebble formation model; The sand and gravel formation simulation module identifies the underground geological structure and formation interface of the sand and gravel formation to be simulated based on drilling geophysical data and geological exploration information, and obtains a refined representation of the formation interface, a representation of the formation permeability attribute, and a representation of the formation water-rich degree attribute. Based on the refined representation of the formation interface, each formation interface is three-dimensionally printed and fixed in a test model cylinder, and according to the representation of the formation permeability attribute and the representation of the formation water-rich degree attribute, the formation medium is filled layer by layer to complete the construction of the sand and gravel formation model.

2. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology according to claim 1 is characterized in that: The identification of the underground geological structure and the stratum interface of the sandy and gravel stratum to be simulated, and obtaining the refined representation of the stratum interface, the stratum permeability attribute representation and the stratum water-rich degree attribute representation are specifically as follows: By drilling and coring the simulated sand and gravel strata, the porosity and permeability of the strata at different depths are analyzed, and the characteristic points of the interface are determined according to the strata attribute differences and attribute difference thresholds within different height ranges, so as to form a preliminary fitting strata interface. Based on the analysis of seismic wave signals, the underground geological structure and stratigraphic interfaces are identified based on the preliminary fitted stratigraphic interfaces, and the stratigraphic types, porosity, permeability and water-richness of the optimized stratigraphic interfaces and between the stratigraphic interfaces are obtained.

3. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology as claimed in claim 2 is characterized in that: The three-dimensional printing of the interfaces of various strata is specifically as follows: Based on the optimized interfaces of each stratum, the stratum skeleton is digitally modeled through 3D modeling technology, and the stratum interfaces in the model are three-dimensionally printed.

4. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology according to claim 1 is characterized in that: The test model cylinder is assembled from a plurality of different stratigraphic units from bottom to top, and the stratigraphic units are divided by stratigraphic interfaces; The inner wall of the cylinder is made of a high-pressure-resistant silicone composite material with a gel inner ring. The inner ring is provided with closely arranged sliding grooves to accurately fix and adjust the position of the three-dimensionally formed stratum interface. A stereoscopic observation window made of high-strength transparent material is provided on the test model cylinder to observe the three-dimensional local diffusion and flow of the slurry during the grouting process.

5. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology as claimed in claim 4 is characterized in that: The fixing in the test model cylinder is based on the relative heights of the various stratum interfaces, and the printed stratum interface is embedded in the slidable groove of the test model cylinder.

6. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology according to claim 1 is characterized in that: The filling of the formation medium layer by layer is to select the filling medium to fill the formation units between the interfaces according to the formation type, porosity, permeability and water-richness between the interfaces of the sand and gravel formation.

7. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology according to claim 1 is characterized in that: The filling medium includes two types: Using in-situ formation media of the sand-pebble formation to be simulated; The formation medium is printed using 3D printing technology based on porosity, permeability and water richness.

8. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology as claimed in claim 1 is characterized in that: The anti-segregation double-liquid grouting module includes two constant-speed double-liquid piston grouting pumps, a grout storage tank and a grouting pipeline; The bottom of the constant speed dual-liquid piston grouting pump is provided with a sonic vibration device and a pressurized air nozzle. When the cement slurry enters the slurry storage tank, the sonic vibration device and the pressurized air nozzle are started synchronously to ensure that the cement slurry always maintains uniform distribution and stability during the grouting process.

9. The sand and gravel stratum grouting simulation test system based on three-dimensional molding technology as claimed in claim 1, characterized in that: It also includes an information collection module and a data analysis module; The information acquisition module uses sensors to collect data during the grouting process; The data analysis module analyzes the data collected by the sensor.

10. A grouting simulation test method for sand and gravel formations based on three-dimensional molding technology, characterized in that: include: Based on the drilling geophysical data and geological exploration information, the underground geological structure and stratigraphic interface of the sand and gravel strata to be simulated are identified, and the refined representation of the stratigraphic interface, the stratigraphic permeability attribute representation and the stratigraphic water-rich degree attribute representation are obtained; based on the refined representation of the stratigraphic interface, each stratigraphic interface is three-dimensionally printed and fixed in the test model cylinder, and according to the stratigraphic permeability attribute representation and the stratigraphic water-rich degree attribute representation, the stratigraphic medium is filled layer by layer to complete the construction of the sand and gravel strata model; Grouting was injected into the constructed sand-pebble stratum model to conduct a grouting simulation test of the sand-pebble stratum.

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