Method for preparing surrounding rock-sprayed concrete lining physical model considering interface characteristics

Abstract

The invention provides a surrounding rock-sprayed concrete lining physical model preparation method considering interface characteristics, and belongs to the technical field of tunnel and underground construction engineering, the preparation method comprises the following steps: assembling a surrounding rock-concrete composite layer mold based on an interface roughness mold, an outer ring mold and an inner ring mold; based on the surrounding rock-concrete composite layer mold, a surrounding rock-sprayed concrete composite layer test piece is poured; mounting and fixing the surrounding rock-sprayed concrete composite layer test piece on a loading device; applying a load to the surrounding rock-sprayed concrete composite layer test piece through a loading device until the surrounding rock-sprayed concrete composite layer test piece is damaged; acquiring test data in the test process, and drawing a load-displacement curve and a strain-displacement curve based on the test data. Through the interface roughness mold, the modular loading device and the data acquisition module, the real mechanical property of the tunnel surrounding rock is accurately reflected, and a scientific basis is provided for mechanical property research of the tunnel surrounding rock-sprayed concrete lining.

Description

Technical Field

[0001] This application belongs to the technical field of tunnel and underground construction engineering, and specifically relates to a method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics. Background Art

[0002] With the rapid development of transportation infrastructure construction, deep - tunnel projects are increasing day by day. Deep - buried tunnels face complex geological conditions such as high ground stress, high osmotic pressure, high ground temperature, and dynamic disturbances, which easily lead to damage phenomena such as spalling and disintegration of the surrounding rock, seriously threatening the safety of tunnel lining structures and the lives and property of construction workers.

[0003] To address the rockburst impact problem in deep - tunnel engineering, the engineering community mainly adopts reinforcement measures such as steel mesh support, bolt support, and shotcrete support. Among them, shotcrete support shows significant advantages in controlling the deformation of the surrounding rock and resisting rockburst impact because it can effectively avoid stress concentration at the support interface and improve the interface bonding performance.

[0004] At present, there are mainly three types of methods for testing the mechanical properties of tunnel linings: full - numerical calculation methods, scaled - down structure tests, and small - scale full - scale tests. However, there are obvious deficiencies in the existing technology for simulating the mechanical properties of the surrounding rock - shotcrete composite lining: traditional ordinary tunnel lining mechanical property tests are difficult to simulate the mechanical response of the real tunnel surrounding rock - shotcrete composite interface; for the tunnel surrounding rock - shotcrete composite layer structure, single numerical simulation has many limitations, and it is difficult to simulate its real mechanical response under dynamic impact, and there are large deviations in the simulation of the interface of the structural composite layer. The numerical simulation method obviously cannot accurately reflect the real stress and deformation characteristics of the structure. The existing testing methods seriously restrict the development of the surrounding rock - shotcrete composite lining technology, and there is an urgent need to develop new test methods to accurately simulate and test the real mechanical properties of the composite lining interface. Summary of the Invention

[0005] Therefore, the purpose of this application is to provide a method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics, and to solve at least one technical problem existing in the prior art.

[0006] To solve the above problems, this application provides a method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics, including: Assembling a surrounding - rock - concrete composite layer mold based on an interface roughness mold, an outer - ring mold, and an inner - ring mold; Pouring a surrounding - rock - shotcrete composite layer specimen based on the surrounding - rock - concrete composite layer mold; Installing and fixing the surrounding - rock - shotcrete composite layer specimen on a loading device; Apply a load to the surrounding rock - shotcrete composite layer specimen through a loading device until the surrounding rock - shotcrete composite layer specimen is damaged; Obtain the test data during the test, and draw a load - displacement curve and a strain - displacement curve based on the test data.

[0007] Optionally, the step of casting the surrounding rock - shotcrete composite layer specimen based on the surrounding rock - concrete composite layer mold includes: The interface roughness mold and the outer ring mold form a casting area for the surrounding rock specimen. Cast the surrounding rock specimen in the casting area for the surrounding rock specimen; after the surrounding rock specimen is demolded, place it in a curing room for curing; Put the fabricated surrounding rock specimen back into the surrounding rock - concrete composite layer mold. The surrounding rock specimen and the inner ring mold form a casting area for the concrete specimen. Cast the concrete specimen in the casting area for the concrete specimen to form a surrounding rock - shotcrete composite layer specimen; after the surrounding rock - shotcrete composite layer specimen is demolded, place it in a curing room for curing.

[0008] Optionally, before the step of installing and fixing the surrounding rock - shotcrete composite layer specimen on the loading device, it further includes: Assemble the loading device: According to the size of the surrounding rock - shotcrete composite layer specimen, assemble the peripheral loading frame of the loading device; install the loading part and the spring columns on the inner side wall of the peripheral loading frame; fix the rubber plates on each of the spring columns one by one.

[0009] Optionally, the step of installing and fixing the surrounding rock - shotcrete composite layer specimen on the loading device includes: Install the surrounding rock - shotcrete composite layer specimen between the rubber plates of the loading device; adjust the position of the surrounding rock - shotcrete composite layer specimen on the rubber plates and fix the surrounding rock - shotcrete composite layer specimen.

[0010] Optionally, there are at least two loading parts, and the models of the two loading parts are different.

[0011] Optionally, before the step of applying a load to the surrounding rock - shotcrete composite layer specimen through the loading device until the surrounding rock - shotcrete composite layer specimen is damaged, it further includes: Install the data acquisition module on the surface of the surrounding rock - shotcrete composite layer specimen; Connect the data acquisition module and the loading part to the host computer.

[0012] Optionally, the data acquisition module includes a pressure sensor, a displacement sensor, and a strain gauge. The pressure sensor is used to collect load data, the displacement sensor is used to collect displacement data, and the strain gauge is used to collect strain data. The measurement ends of the pressure sensor, the displacement sensor, and the strain gauge are installed on the surface of the surrounding rock-shotcrete composite layer specimen. The transmission ends of the pressure sensor, the displacement sensor, and the strain gauge are connected to the host computer for transmitting load, displacement, and strain data to the host computer.

[0013] Optionally, the pressure sensor is arranged between the loading end of the loading part and the surface of the surrounding rock-shotcrete composite layer specimen. The displacement sensors are symmetrically arranged on both sides of the surrounding rock-shotcrete composite layer specimen in the loading direction. The strain gauges are arranged at intervals along the circumference of the surrounding rock-shotcrete composite layer specimen.

[0014] Optionally, before the step of assembling the surrounding rock-concrete composite layer mold based on the interface roughness mold, the outer ring mold, and the inner ring mold, it further includes; Obtain the interface line shape of the tunnel surrounding rock interface, and draw a three-dimensional model of the interface roughness mold based on the interface line shape; Manufacture the interface roughness mold based on the three-dimensional model of the interface roughness mold.

[0015] Optionally, the step of obtaining the interface line shape of the tunnel surrounding rock interface and drawing a three-dimensional model of the interface roughness mold based on the interface line shape includes: Obtain the surface topography of the tunnel surrounding rock interface, extract the interface line shape data of the surrounding rock interface, and draw the interface line shape of the tunnel surrounding rock interface based on the interface line shape data of the surrounding rock interface; According to the interface line shape of the tunnel surrounding rock interface, draw a three-dimensional model of the interface roughness mold through three-dimensional modeling software.

[0016] By means of the above technical solution, the invention of the present application has at least the following beneficial effects: The embodiment of the present application provides a method for preparing a physical model of a surrounding rock-shotcrete lining composite layer considering interface characteristics. By designing an interface roughness mold, a modular loading device, and a data acquisition module, it effectively solves the problems of simulation distortion, equipment limitations, and dynamic response evaluation in the background technology, accurately reflects the true mechanical properties of the tunnel surrounding rock, and provides a scientific and reliable test method for the mechanical property research of the tunnel surrounding rock-shotcrete composite lining. Description of the Drawings

[0017] Figure 1 Flow chart of the method for preparing a physical model of a surrounding rock-shotcrete lining composite layer considering interface characteristics according to the embodiment of the present application Figure 1 ; Figure 2 Preparation method flow of surrounding rock - shotcrete lining composite layer considering interface characteristics in the embodiment of the present application Figure 2 ; Figure 3 Schematic diagram of the casting process of the surrounding rock - shotcrete composite layer specimen in the embodiment of the present application; Figure 4 Schematic diagram of the loading device loading the surrounding rock - shotcrete composite layer specimen in the embodiment of the present application.

[0018] The reference numerals are represented as: 1. Outer loading frame; 2. Loading jack; 3. Spring column; 4. Rubber plate; 5. Interface roughness mold; 6. Outer ring mold; 7. Inner ring mold; 8. Surrounding rock specimen; 9. Concrete specimen. Specific embodiments

[0019] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0020] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0021] In the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] The following describes the preferred embodiments of the present invention with reference to the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0023] With reference to Figure 1 、 Figure 3 and Figure 4 shown, according to an embodiment of the present application, a method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics is provided, including: Step S11, assembling a surrounding rock - concrete composite layer mold based on an interface roughness mold 5, an outer ring mold 6, and an inner ring mold 7.

[0024] Among them, the interface roughness mold 5 is made based on the scanning data of the actual tunnel surrounding rock, and its surface shape is consistent with the real tunnel surrounding rock interface; The outer ring mold 6 and the inner ring mold 7 adopt a detachable design for easy demolding.

[0025] Step S12, pouring a surrounding rock - shotcrete composite layer specimen based on the surrounding rock - concrete composite layer mold.

[0026] The concrete for pouring the surrounding rock specimen 8 is different from the concrete for pouring the concrete specimen 9; the concrete for pouring the surrounding rock specimen 8 uses a rock - like material.

[0027] Step S13, installing and fixing the surrounding rock - shotcrete composite layer specimen on the loading device.

[0028] Step S14, applying a load to the surrounding rock - shotcrete composite layer specimen through the loading device until the surrounding rock - shotcrete composite layer specimen is damaged.

[0029] Among them, the loading adopts a displacement - control mode, and the loading speed is set to 0.5 mm / min; the loading continues until obvious cracks or interface peeling occur in the surrounding rock - shotcrete composite layer specimen.

[0030] Step S15, obtaining the test data during the test process, and drawing a load - displacement curve and a strain - displacement curve based on the test data.

[0031] By designing the interface roughness mold 5, the modular loading device, and the data acquisition module, the problems of simulation distortion, equipment limitations, and dynamic response evaluation existing in the background technology are effectively solved, accurately reflecting the true mechanical properties of the tunnel surrounding rock, and providing a scientific and reliable test method for the mechanical property research of the tunnel surrounding rock - shotcrete composite lining.

[0032] As a refinement and extension of the specific implementation manner of the above - mentioned embodiment, in order to completely illustrate the specific implementation process of this embodiment, as shown, another method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics is provided, and this method includes: Figure 2 shown, another method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics is provided, and this method includes: Step S21, obtaining the interface linear shape of the tunnel surrounding rock interface, and drawing the interface roughness mold three-dimensional model based on the interface linear shape.

[0033] Step S21.1 obtains the surface morphology of the tunnel surrounding rock interface, extracts the surrounding rock interface linear data, and draws the interface linear shape of the tunnel surrounding rock interface based on the surrounding rock interface linear data.

[0034] Specifically: use a 3D laser scanner to scan the actual tunnel surrounding rock interface to obtain high-precision surrounding rock interface linear data; at the same time, use a mirror-assisted scanning system to depict the interface line shape of the tunnel surrounding rock interface.

[0035] The 3D laser scanner can quickly obtain 3D point cloud data of the actual tunnel surrounding rock surface with an accuracy of millimeter or even sub-millimeter level, ensuring that details such as interface roughness and undulating morphology are fully recorded. The mirror-assisted scanning system can make up for the blind spots of laser scanning in shadow areas or complex geometric parts (such as depressions and holes), supplement data through multi-angle reflection, and avoid information loss. The two jointly quantitatively depict the interface shape of the surrounding rock-shotcrete composite layer specimen, and can generate a complete digital model of the surrounding rock interface, providing a high-fidelity basis for subsequent mold production.

[0036] Step S21.2, based on the interface line shape of the tunnel surrounding rock interface, draw a three-dimensional model of the interface roughness mold using three-dimensional modeling software.

[0037] Specifically, the interface linearity of the tunnel surrounding rock interface is imported into the 3D modeling software to generate a 3D model of the interface roughness mold.

[0038] In this embodiment, the three-dimensional modeling software is SOLIDWORKS modeling software.

[0039] Step S22, manufacturing the interface roughness mold 5 based on the interface roughness mold three-dimensional model.

[0040] Specifically, a JGMaker A5S 3D printer is used to print the interface roughness mold 5, and a high-strength polymer material is selected as the material.

[0041] The interface roughness mold 5 is made based on the scanning data of the actual tunnel surrounding rock. Its surface shape is consistent with the real tunnel surrounding rock interface, including macroscopic undulations and microscopic roughness, and can accurately reproduce the bite effect, friction behavior and stress distribution of the surrounding rock-concrete interface. It avoids the mechanical property deviation caused by traditional simplified molds (such as artificial roughening or standard waveforms), and the test results are closer to engineering reality.

[0042] The real interface morphology directly affects the shear strength, bonding performance and failure mode of the composite structure. The high-fidelity mold ensures that the test can reflect the interaction mechanism between the surrounding rock and the lining in the actual tunnel.

[0043] The interface roughness mold 5 based on real scanned data solves the pain point that traditional methods cannot restore the complex morphology of rock masses, enabling physical tests to more realistically reflect the mechanical behavior of the surrounding rock-concrete composite structure and providing a more accurate reference basis for tunnel design and construction.

[0044] Step S23: Assemble the surrounding rock-concrete composite layer mold based on the interface roughness mold 5, the outer ring mold 6, and the inner ring mold 7.

[0045] The outer ring mold 6 and the inner ring mold 7 adopt a detachable design for easy demolding.

[0046] Step S24: Pour the surrounding rock-shotcrete composite layer specimen based on the surrounding rock-concrete composite layer mold.

[0047] The cast concrete of the surrounding rock specimen 8 is different from that of the concrete specimen 9; the cast concrete of the surrounding rock specimen 8 uses a rock-like material.

[0048] Step S24.1: The interface roughness mold 5 and the outer ring mold 6 form the casting area for the surrounding rock specimen. Pour the surrounding rock specimen 8 in the casting area for the surrounding rock specimen; after the surrounding rock specimen 8 is demolded, place it in the curing room for curing.

[0049] Specifically, first prepare and pour the surrounding rock specimen 8 in the casting area for the surrounding rock specimen according to the set mix ratio (different specimen sizes can be selected according to actual situations). After standing for 24 hours, demold the surrounding rock specimen 8 and place it in the standard curing room for 28 days; Strictly prepare the rock-like material (such as gypsum-based or cement-based simulation materials) according to the design mix ratio, which can accurately reproduce the mechanical properties of specific surrounding rocks (such as compressive strength, elastic modulus), and avoid the discreteness of test data caused by uneven materials.

[0050] Through the curing treatment, the rock-like material is fully hydrated to reach the design strength; simulate the working condition of the long-term interaction between the surrounding rock and the lining in tunnel engineering, and reflect the influence of time on the interface bonding performance.

[0051] Step S24.2: Re-place the fabricated surrounding rock specimen 8 into the surrounding rock-concrete composite layer mold. The surrounding rock specimen 8 and the inner ring mold 7 form the casting area for the concrete specimen. Pour the concrete specimen 9 in the casting area for the concrete specimen to form the surrounding rock-shotcrete composite layer specimen; after the surrounding rock-shotcrete composite layer specimen is demolded, place it in the curing room for curing.

[0052] Specifically: Re-put the surrounding rock specimen 8 into the surrounding rock-concrete composite layer mold. At this time, the surrounding rock specimen 8 and the inner ring mold 7 form a casting area for the concrete specimen. Pour the concrete specimen 9 in the casting area of the concrete specimen according to the set mix ratio to form a surrounding rock-sprayed concrete composite layer specimen. After standing for 24 hours, demold the surrounding rock-sprayed concrete composite layer specimen and place it in a standard curing room for 28 days to complete the casting of the surrounding rock-sprayed concrete composite layer specimen.

[0053] Through the step-by-step casting process, the interfacial bonding state between the surrounding rock and the concrete in the actual project can be accurately reproduced. The surrounding rock specimen 8, as part of the mold, ensures perfect fit with the surface of the surrounding rock during concrete casting, maintains the integrity of the interfacial roughness characteristics, and truly reflects the interaction mechanism between the surrounding rock and the concrete.

[0054] Step S25: Assemble the loading device.

[0055] According to the size of the surrounding rock-sprayed concrete composite layer specimen, assemble the outer loading frame 1 of the loading device; install the loading part and the spring column 3 on the inner side wall of the outer loading frame 1; fix the rubber plates 4 on each spring column 3 one by one.

[0056] Specifically, according to the size of the cast surrounding rock-sprayed concrete composite layer specimen, assemble multiple loading frames to form the outer loading frame 1. Fix each loading frame with screws. Install the loading part on the inner wall of one of the loading frames, and install the spring column 3 under each of the remaining loading frames. Fix the support at the end of the spring column 3 on the inner wall of the outer loading frame 1 with screws. That is to say, fix the spring column 3 on the inner wall of the outer loading frame 1, and fix the rubber plate 4 on the end of the spring column 3 one by one through bolts.

[0057] The design of the modular loading device allows adapting to different sizes of surrounding rock-sprayed concrete composite layer specimens (from small laboratory specimens to full-scale models) by increasing or decreasing the number of loading frames. The pre-tightening force of the spring column 3 can be adjusted by screws to achieve precise hierarchical control of the load; the flexible contact of the rubber plate 4 ensures uniform load distribution and avoids stress concentration. The multi-directional spring column 3 can simultaneously simulate the radial pressure and tangential restraint of the surrounding rock. The elastic deformation characteristics of the rubber plate 4 can reproduce the rheological characteristics of the surrounding rock. By differentially pre-tightening the spring columns 3 at different positions, a non-uniform stress field can be constructed. The spring-rubber combination system breaks through the limitations of traditional rigid loading and can more truly reflect the dynamic interaction between the tunnel support structure and the surrounding rock.

[0058] There are at least two loading parts, and the models of the two loading parts are different. In this embodiment, the loading part is the loading jack 2. By setting different models of loading jacks 2, the mechanical property tests of the surrounding rock-sprayed concrete composite layer specimens with different loading requirements can be handled.

[0059] Step S26: Install and fix the surrounding rock - shotcrete composite layer specimen on the loading device.

[0060] Specifically: Install the surrounding rock - shotcrete composite layer specimen between the rubber plates 4 of the loading device; adjust the position of the surrounding rock - shotcrete composite layer specimen on the rubber plates 4 and fix the surrounding rock - shotcrete composite layer specimen. Accurately simulate the engineering boundary conditions to ensure the authenticity of load transfer.

[0061] Step S27: Install the data acquisition module.

[0062] Step S27.1: Install the data acquisition module on the surface of the surrounding rock - shotcrete composite layer specimen.

[0063] Specifically, the data acquisition module includes a pressure sensor, a displacement sensor, and strain gauges. The pressure sensor is used to collect load data, the displacement sensor is used to collect displacement data, and the strain gauges are used to collect strain data; the measuring ends of the pressure sensor, the displacement sensor, and the strain gauges are installed on the surface of the surrounding rock - shotcrete composite layer specimen.

[0064] The pressure sensor is set between the loading end of the loading part and the surface of the surrounding rock - shotcrete composite layer specimen; directly record the true transferred load to eliminate interference factors such as system friction and measure the pure interface acting force.

[0065] The displacement sensors are symmetrically arranged on both sides of the surrounding rock - shotcrete composite layer specimen in the loading direction; bilateral measurement eliminates the specimen deflection error.

[0066] The strain gauges are arranged at intervals along the circumferential direction of the surrounding rock - shotcrete composite layer specimen; the interval arrangement forms a strain field monitoring network to capture the non - uniformity of the circumferential strain distribution, locate the initial cracking position and development path.

[0067] Step S27.2: Connect the data acquisition module and the loading part to the upper computer.

[0068] Specifically, the transmission ends of the pressure sensor, the displacement sensor, and the strain gauges are connected to the upper computer, which is used to transmit the load, displacement, and strain data to the upper computer.

[0069] Step S28: Apply a load to the surrounding rock - shotcrete composite layer specimen through the loading device until the surrounding rock - shotcrete composite layer specimen is damaged.

[0070] Among them, the loading adopts the displacement control mode, and the loading speed is set to 0.5 mm / min; the loading continues until obvious cracks or interface peeling occur on the surrounding rock - shotcrete composite layer specimen.

[0071] Step S29: Obtain the test data during the test process, and draw the load-displacement curve and the strain-displacement curve based on the test data.

[0072] Specifically: The load data applied by the loading part is detected in real time through a pressure sensor; the displacement data is detected in real time through a position sensor; the strain data of the surrounding rock-sprayed concrete composite layer specimen is detected in real time through a strain gauge; the data collected by the pressure sensor, displacement sensor and strain gauge are transmitted to the host computer to obtain the load-displacement curve and the strain-displacement curve.

[0073] Through 3D laser scanning and mold manufacturing technology, the interface shape of the real tunnel surrounding rock is accurately reproduced to ensure that the interface characteristics of the specimen are consistent with the actual project, so as to more realistically simulate the mechanical response of the composite interface.

[0074] A modular loading device (adjustable loading frame, spring column 3, rubber plate 4 and double loading jack 2) is provided, which can adapt to different sizes of specimens and loading conditions, solves the problems of universality and flexibility of test equipment, and realizes the mechanical property tests of surrounding rock-sprayed concrete composite layer specimens with different specimen sizes and different load sizes.

[0075] Through step-by-step pouring (surrounding rock specimen 8 and concrete specimen 9) and standard curing, the bond strength of the composite layer interface is ensured to be close to the actual working condition. Combined with the pressure sensor, displacement sensor and strain gauge, the load-displacement and strain-displacement curves are accurately measured, providing reliable data for evaluating the impact resistance of the support structure.

[0076] A loading system using a rubber plate 4 for buffering and a spring column 3 for supporting is adopted to simulate the dynamic action of soil pressure on the tunnel. At the same time, loading is carried out through the displacement control mode, which more realistically reflects the failure mechanism of the composite lining under dynamic loads.

[0077] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0078] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present application, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics, characterized in that, Including: Assembling a surrounding rock-concrete composite layer mold based on an interface roughness mold (5), an outer ring mold (6) and an inner ring mold (7); Pouring a surrounding rock-sprayed concrete composite layer specimen based on the surrounding rock-concrete composite layer mold; Installing and fixing the surrounding rock-sprayed concrete composite layer specimen on a loading device; Applying a load to the surrounding rock-sprayed concrete composite layer specimen through the loading device until the surrounding rock-sprayed concrete composite layer specimen is damaged; Obtaining test data during the test process and drawing a load-displacement curve and a strain-displacement curve based on the test data.

2. The method for preparing a physical model of surrounding rock - shotcrete lining considering interface characteristics according to claim 1, wherein, The step of pouring the surrounding rock-sprayed concrete composite layer specimen based on the surrounding rock-concrete composite layer mold includes: The interface roughness mold (5) and the outer ring mold (6) form a surrounding rock specimen pouring area, and a surrounding rock specimen (8) is poured in the surrounding rock specimen pouring area; after the surrounding rock specimen (8) is demolded, it is placed in a curing chamber for curing; The made surrounding rock specimen (8) is re-placed into the surrounding rock-concrete composite layer mold. The surrounding rock specimen (8) and the inner ring mold (7) form a concrete specimen pouring area, and a concrete specimen (9) is poured in the concrete specimen pouring area to form a surrounding rock-sprayed concrete composite layer specimen; after the surrounding rock-sprayed concrete composite layer specimen is demolded, it is placed in a curing chamber for curing.

3. The method for preparing a surrounding rock-shotcrete lining physical model considering interface characteristics according to claim 1, characterized in that Before the step of installing and fixing the surrounding rock-sprayed concrete composite layer specimen on the loading device, it further includes: Assembling the loading device: According to the size of the surrounding rock-sprayed concrete composite layer specimen, assembling the peripheral loading frame (1) of the loading device; installing the loading part and the spring column (3) on the inner side wall of the peripheral loading frame (1); fixing the rubber plates (4) one by one on each of the spring columns (3).

4. The method for preparing a physical model of surrounding rock-shotcrete lining considering interface characteristics according to claim 3, characterized in that, The step of installing and fixing the surrounding rock-sprayed concrete composite layer specimen on the loading device includes: Installing the surrounding rock-sprayed concrete composite layer specimen between the rubber plates (4) of the loading device; adjusting the position of the surrounding rock-sprayed concrete composite layer specimen on the rubber plates (4) and fixing the surrounding rock-sprayed concrete composite layer specimen.

5. The method for preparing a physical model of surrounding rock-shotcrete lining considering interface characteristics according to claim 3, characterized in that, There are at least two loading parts, and the models of the two loading parts are different.

6. The method for preparing a physical model of surrounding rock-shotcrete lining considering interface characteristics according to claim 1, characterized in that, Before the step of applying a load to the surrounding rock-sprayed concrete composite layer specimen through the loading device until the surrounding rock-sprayed concrete composite layer specimen is damaged, it further includes: Installing a data acquisition module on the surface of the surrounding rock-sprayed concrete composite layer specimen; Connecting the data acquisition module and the loading part to a host computer.

7. The method for preparing a physical model of surrounding rock-shotcrete lining considering interface characteristics according to claim 6, characterized in that, The data acquisition module includes a pressure sensor, a displacement sensor and a strain gauge. The pressure sensor is used to collect load data, the displacement sensor is used to collect displacement data, and the strain gauge is used to collect strain data; the measuring ends of the pressure sensor, the displacement sensor and the strain gauge are installed on the surface of the surrounding rock-sprayed concrete composite layer specimen; the transmission ends of the pressure sensor, the displacement sensor and the strain gauge are connected to the host computer for transmitting the load, displacement and strain data to the host computer.

8. The method for preparing a surrounding rock-shotcrete lining physical model considering interface characteristics according to claim 7, characterized in that The pressure sensor is disposed between the loading end of the loading part and the surface of the surrounding rock-shotcrete composite layer specimen; the displacement sensors are symmetrically arranged on both sides of the surrounding rock-shotcrete composite layer specimen in the loading direction; the strain gauges are arranged at intervals along the circumferential direction of the surrounding rock-shotcrete composite layer specimen.

9. The method for preparing a physical model of surrounding rock-shotcrete lining considering interface characteristics according to claim 1, characterized in that, Before the step of assembling the surrounding rock-concrete composite layer mold based on the interface roughness mold (5), the outer ring mold (6) and the inner ring mold (7), it further includes; Obtaining the interface line shape of the tunnel surrounding rock interface and drawing a three-dimensional model of the interface roughness mold based on the interface line shape; Manufacturing the interface roughness mold (5) based on the three-dimensional model of the interface roughness mold.

10. The method for preparing a physical model of surrounding rock-shotcrete lining considering interface characteristics according to claim 9, characterized in that, The step of obtaining the interface line shape of the tunnel surrounding rock interface and drawing a three-dimensional model of the interface roughness mold based on the interface line shape includes: Obtaining the surface topography of the tunnel surrounding rock interface, extracting the surrounding rock interface line shape data, and drawing the interface line shape of the tunnel surrounding rock interface based on the surrounding rock interface line shape data; Drawing a three-dimensional model of the interface roughness mold through three-dimensional modeling software according to the interface line shape of the tunnel surrounding rock interface.

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