A method for correcting the bearing capacity of rock anchors in field scaled model tests

Abstract

The present invention discloses a method for correcting the bearing capacity results of a rock anchor anchoring field scaled model test, which belongs to the field of field rock mass mechanics testing and includes conducting a rock anchor anchoring field scaled model test; obtaining the rock anchor anchoring bearing capacity test value and the bearing body failure contour; calculating the rock anchor anchoring bearing body volume and gravity; performing a force analysis on the rock anchor anchoring bearing body; drawing a force analysis diagram of the rock anchor anchoring bearing body; amplifying the gravity component on the rock anchor anchoring bearing body force analysis diagram and redrawing the corrected force analysis diagram; and obtaining a rock anchor anchoring bearing capacity correction value. The present invention reveals the mechanical mechanism of rock anchor anchoring and has the advantages of being theoretically reliable and simple to operate. By correcting the bearing capacity obtained from the rock anchor anchoring field scaled model test, the problem of conservative bearing capacity test results can be solved, the authenticity of the results can be improved, the guiding significance of the test to the project can be enhanced, and the promotion and application of the rock anchor anchoring field scaled model test in engineering practice can be promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of on-site rock mass mechanics testing, and in particular to a method for correcting the bearing capacity of a rock anchor on-site scaled model test. Background Art

[0002] Since the beginning of the new era, my country's economy has experienced rapid growth. To meet the people's ever-growing needs for a better life, the construction of transportation infrastructure such as highways and high-speed railways has been in full swing. A large number of suspension bridges, spanning major rivers and deep ravines, have sprung up across China. Anchors are a crucial foundational load-bearing structure for suspension bridges. In the past, due to economic and technological constraints, suspension bridge anchors typically employed gravity anchors and tunnel anchors, accumulating extensive engineering experience and research achievements in these systems. Compared to gravity and tunnel anchors, rock anchors are a new type of anchor structure. Reinforced concrete anchor plates are cast on the surface of a mountain. After excavation, anchor holes are excavated and reinforced concrete anchor plates are cast within the mountain. Dozens of holes are drilled between the front and rear anchor plates to embed prestressed anchor cables. By applying prestress to the rock mass clamped by the front and rear anchor plates, a load-bearing structure is formed to bear the tension of the suspension bridge's main cables. It has the significant advantages of small engineering volume, economy and environmental protection, and fully utilizes the bearing capacity of the rock mass. However, the structure is novel and the mechanical mechanism is complex. At present, there are not many cases of using rock anchoring schemes abroad, and China has only begun to explore the use of this anchoring scheme. How to demonstrate the bearing capacity and safety and stability of rock anchoring is a technical direction that urgently needs to be focused on.

[0003] Currently, the bearing capacity and safety and stability evaluation of rock anchors are typically conducted using theoretical calculations and analysis, field scaled model tests, and numerical simulations. Drawing on the research history and experience of tunnel anchors, conducting field scaled model tests of rock anchors is a reliable method for intuitively assessing their bearing capacity. However, field scaled model tests of rock anchors are based on the similarity principle of elastic mechanics. This requires that the model and prototype be constructed from the same material, with the model's geometric dimensions scaled down proportionally from the prototype's structural dimensions. Test loads are applied to the model based on similarity relationships, but this ignores the effect of the scaled model's inherent gravity failing to meet the similarity relationship. According to the similarity principle, the gravity of the scaled rock anchor model is significantly reduced compared to theoretical values. However, gravity is a resisting force for the entire rock anchor load system, resulting in bearing capacity results from field scaled model tests being lower than the actual value. How to reduce the discrepancies between rock anchor field scaled model testing techniques and the true description of the mechanical properties of prototype rock anchors, improve the fidelity of bearing capacity results, and enhance the guiding significance of rock anchor field scaled model testing for engineering projects is particularly urgent and important. An extensive literature review has revealed no reports on improvements to rock anchor field scaled model testing techniques or corrections to results. Due to the limitations of field rock mechanics testing methods, improvements in field scaled model construction and loading techniques are difficult to implement. Therefore, developing a theoretically derived method for post-test bearing capacity correction is of great value. Summary of the Invention

[0004] In order to solve the problem in the prior art that the bearing capacity results obtained from the existing rock anchor anchorage on-site scaled model test are too conservative, the present invention provides a bearing capacity correction method for the rock anchor anchorage on-site scaled model test.

[0005] To achieve the above technical solution, the present invention provides a method for correcting the bearing capacity of a rock anchor anchorage in a scaled model test on site, comprising the following steps:

[0006] S1: Construct a scaled model of rock anchor and conduct on-site scaled model test of rock anchor;

[0007] S2: Obtain the rock anchor bearing capacity test value and bearing body failure contour;

[0008] S3: Calculate the volume and gravity of the rock anchor bearing body;

[0009] S4: Conduct stress analysis on the rock anchor bearing body;

[0010] S5: Draw the force analysis diagram of the rock anchor bearing body;

[0011] S6: Enlarge the gravity component on the force analysis diagram of the rock anchor bearing body and redraw the corrected force analysis diagram;

[0012] S7: Obtain the correction value of the rock anchor bearing capacity.

[0013] Furthermore, step S1 includes the following sub-steps:

[0014] S1.1: Design a scaled model of the rock anchor according to the similarity principle of elastic mechanics. Select a location with representative engineering geological conditions in the actual bridge rock anchor project area and construct a rock anchor model with a scale ratio of 1:N according to the similarity principle. When physical force is ignored, the similarity relationship between the model and the prototype is:

[0015] Geometric dimensions: ;

[0016] Elastic modulus: ;

[0017] strength: ;

[0018] Load: ;

[0019] S1.2: Install loading and measuring equipment;

[0020] S1.3: Load and measure a scaled model of the rock anchor until failure, and plot the load-displacement curve.

[0021] Furthermore, step S2 includes the following sub-steps:

[0022] S2.1: Obtain the maximum applied load from the load-displacement curve measured during the loading process of the scaled rock anchor model and determine it as the bearing capacity of the scaled rock anchor model;

[0023] S2.2: By analyzing the time and space of the surface cracks exposed inside and outside the rock anchor model, generalize the failure mode of the rock anchor and the failure profile of the bearing body.

[0024] Furthermore, step S3 includes the following sub-steps:

[0025] S3.1: Draw the three-dimensional shape of the rock anchor bearing body by generalizing the failure contour of the rock anchor bearing body, and calculate the volume of the rock anchor bearing body;

[0026] S3.2: Based on the calculated volume of the rock anchor bearing body, consult the geological survey data to obtain the density of the rock anchor rock mass, and calculate the gravity of the rock anchor bearing body using the following formula:

[0027] ;

[0028] Furthermore, step S4 includes the following sub-steps:

[0029] S4.1: Take the rock anchor bearing body as an independent unit and treat it as a rigid body;

[0030] S4.2: Analyze the additional loads applied to the anchorage bearing element during test loading. , the weight W of the rock anchor bearing body itself and the resistance of the external rock mass to the rock anchor bearing body ;

[0031] S4.3: Label the additional loads obtained in step S2 whose magnitude and direction are known. .

[0032] S4.4: Mark the rock anchor bearing body's own weight W, obtained in step S3 and with known magnitude and direction;

[0033] Furthermore, step S5 includes the following sub-steps:

[0034] S5.1: It is assumed that when the rock anchor system fails, all external forces acting on the rock anchor bearing body reach a state of mechanical equilibrium;

[0035] S5.2: Draw a force analysis diagram for the rock anchor bearing body and include and W are drawn end to end;

[0036] S5.3: According to the triangle closure condition principle of the external force on the system in limit equilibrium, obtain the resistance of the external rock mass to the rock anchor bearing body .

[0037] Furthermore, step S6 includes the following sub-steps:

[0038] S6.1: On the force analysis diagram obtained in step S5.3, magnify the weight W of the rock anchor bearing body by N times and use Marking

[0039] S6.2: Determine the new resultant force F by graphical construction;

[0040] S6.3: Decompose the resultant force F along the direction of loading and perpendicular to the direction of the rock anchor test. and .

[0041] S6.4: The resistance of the original external rock mass to the rock anchor bearing body and the increase in the resistance of the external rock mass to the rock anchor bearing body after amplifying gravity According to the graphical method, the vector summation is performed to obtain the total resistance of the external rock mass to the rock anchor bearing body after the gravity is amplified. ;

[0042] S6.5: Based on the obtained 、 and Redraw the revised force analysis diagram.

[0043] Furthermore, step S7 includes the following sub-steps:

[0044] S7.1: Compare the load analysis diagrams before and after correction. and , known The size of the size;

[0045] S7.2: The revised load analysis diagram will be redrawn Determined as the correction value of the rock anchor bearing capacity.

[0046] In summary, the present invention has the following beneficial effects compared to the prior art:

[0047] Based on theoretical analysis and mechanical deduction, the present invention adopts a graphical method to correct the bearing capacity results of the on-site scaled model test of rock anchor anchorage, thereby solving the problem of conservative bearing capacity test results. This can improve the authenticity of the results, enhance the guiding significance of the test to the project, and further promote the promotion and application of the on-site scaled model test of rock anchor anchorage in engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings described herein are used to provide a further understanding of the present invention and constitute a part 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 an improper limitation of the present invention. In the drawings:

[0049] Figure 1 A flow chart of a method for correcting the bearing capacity of a rock anchor in a field scaled model test provided by the present invention;

[0050] Figure 2 Schematic diagram of conducting on-site scale model test of rock anchor in an embodiment of the present invention;

[0051] Figure 3 The following is an effect diagram of the bearing body failure contour obtained from the on-site scale model test of the rock anchor in the embodiment of the present invention;

[0052] Figure 4 FIG1 is a force analysis diagram of the rock anchor bearing body in an embodiment of the present invention;

[0053] Figure 5 This is a force analysis diagram of the modified rock anchor bearing body in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0055] 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 invention. As used herein, unless the context clearly indicates otherwise, the singular form can also include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0056] See also Figure 1 As shown, the present invention provides a method for correcting the bearing capacity of a rock anchor anchorage in a scaled model test on site, comprising the steps of:

[0057] S1: Construct a scaled model of rock anchor and conduct on-site scaled model test of rock anchor;

[0058] S2: Obtain the rock anchor bearing capacity test value and bearing body failure contour;

[0059] S3: Calculate the volume and gravity of the rock anchor bearing body;

[0060] S4: Conduct stress analysis on the rock anchor bearing body;

[0061] S5: Draw the force analysis diagram of the rock anchor bearing body;

[0062] S6: Enlarge the gravity component on the force analysis diagram of the rock anchor bearing body and redraw the corrected force analysis diagram;

[0063] S7: Obtain the correction value of the rock anchor bearing capacity.

[0064] As a preferred embodiment, step S1 includes the following sub-steps:

[0065] S1.1: Design a scaled model of the rock anchor according to the similarity principle of elastic mechanics. Select a location with representative engineering geological conditions in the actual bridge rock anchor project area and construct a rock anchor model with a scale ratio of 1:N according to the similarity principle. When physical force is ignored, the similarity relationship between the model and the prototype is:

[0066] Geometric dimensions: ;

[0067] Elastic modulus: ;

[0068] strength: ;

[0069] Load: ;

[0070] Where: and are the structural geometric length dimensions of the model and prototype respectively; and are the elastic moduli of the model and prototype materials, respectively; and are the strength characteristic values ​​of the model and prototype, respectively; and are the load values ​​applied to the model and prototype respectively; N For scale ratio.

[0071] S1.2: Install loading and measuring equipment;

[0072] S1.3: Load and measure a scaled model of the rock anchor until failure, and plot the load-displacement curve.

[0073] As a preference, step S2 includes the following sub-steps:

[0074] S2.1: Obtain the maximum applied load from the load-displacement curve measured during the loading process of the scaled rock anchor model and determine it as the bearing capacity of the scaled rock anchor model;

[0075] S2.2: By analyzing the time and space of the surface cracks exposed inside and outside the rock anchor model, generalize the failure mode of the rock anchor and the failure profile of the bearing body.

[0076] As a preference, step S3 includes the following sub-steps:

[0077] S3.1: Draw the three-dimensional shape of the rock anchor bearing body by generalizing the failure contour of the rock anchor bearing body, and calculate the volume of the rock anchor bearing body;

[0078] S3.2: Based on the calculated volume of the rock anchor bearing body, consult the geological survey data to obtain the density of the rock anchor rock mass, and calculate the gravity of the rock anchor bearing body using the following formula:

[0079] ;

[0080] Where: W is the weight of the rock anchor bearing body, V is the volume of the rock anchor bearing body, ρ is the density of the rock mass where the rock anchor is anchored, g is the acceleration due to gravity.

[0081] As a preference, step S4 includes the following sub-steps:

[0082] S4.1: Take the rock anchor bearing body as an independent unit and treat it as a rigid body;

[0083] S4.2: Analyze the additional loads applied to the anchorage bearing element during test loading. , the weight W of the rock anchor bearing body itself and the resistance of the external rock mass to the rock anchor bearing body , these three forces constitute all the external forces on the rock anchor bearing body, among which It includes the tensile stress, compressive stress and shear stress on the four surfaces of the rock anchor bearing body failure contour;

[0084] S4.3: Label the additional loads obtained in step S2 whose magnitude and direction are known. .

[0085] S4.4: Mark the rock anchor bearing body's own weight W, obtained in step S3 and with known magnitude and direction;

[0086] As a preference, step S5 includes the following sub-steps:

[0087] S5.1: Assume that when the rock anchor system fails, all failure surfaces on the failure contour of the rock anchor bearing body reach the limit state at the same time. According to the limit equilibrium principle, all external forces acting on the rock anchor bearing body reach the mechanical equilibrium state.

[0088] S5.2: Draw a force analysis diagram for the rock anchor bearing body and include and W are drawn end to end;

[0089] S5.3: According to the triangle closure condition principle of the external force on the system in limit equilibrium, obtain the resistance of the external rock mass to the rock anchor bearing body The resistance is the total vector sum of all forces exerted by the external rock mass on the rock anchor bearing body, without distinguishing the stress distribution and stress resultant on each failure surface of the rock anchor bearing body.

[0090] As a preference, step S6 includes the following sub-steps:

[0091] S6.1: According to the principle of similarity, the gravity of the rock anchor model only needs to be reduced times, actually reduced times, which is reduced by N. On the force analysis diagram obtained in step S5.3, the weight W of the rock anchor bearing body itself is magnified by N times and used Marking

[0092] S6.2: Assume that the failure mode of the rock anchor model remains unchanged after the self-weight stress increases, that is, the failure contour of the rock anchor bearing body remains unchanged. Also, according to the principle that the external force on the system meets the triangle closure condition at the limit equilibrium, the amplified rock anchor bearing body weight is known to be The size and direction of the external rock mass and the resistance of the rock anchor bearing body The magnitude and direction of the new resultant force F can be obtained by graphical construction;

[0093] S6.3: The resultant force F consists of two parts: one is the additional load that the rock anchor model can withstand after the gravity is amplified, and the other is the increase in the resistance of the external rock mass to the rock anchor bearing body after the gravity is amplified. The resultant force F is decomposed along the loading direction of the rock anchor test and its perpendicular direction. and .

[0094] S6.4: The resistance of the original external rock mass to the rock anchor bearing body and the increase in the resistance of the external rock mass to the rock anchor bearing body after amplifying gravity According to the graphical method, the vector summation is performed to obtain the total resistance of the external rock mass to the rock anchor bearing body after the gravity is amplified. ,contrast and , Size ratio The magnitude of the stress distribution on the rock anchor bearing body is large, but in different directions. Its essence is the influence of the rock anchor model on the various distributed stresses on the failure contour surface of the rock anchor bearing body after the deadweight stress increases.

[0095] S6.5: Based on the obtained 、 and Redraw the revised force analysis diagram.

[0096] As a preference, step S7 includes the following sub-steps:

[0097] S7.1: Compare the load analysis diagrams before and after correction. and , known The size of the size;

[0098] S7.2: The revised load analysis diagram will be redrawn Determined as the correction value of the rock anchor bearing capacity.

[0099] In order to prove the reliability of the results obtained in the model correction process of the rock anchor anchorage field scale model test bearing capacity correction method provided by the present invention, this method is demonstrated through the following examples:

[0100] A bridge has a main span of 1,488 mm and a maximum single main cable tension of 324,346 kN. A rock anchor system was used on one bank of the bridge, with the bedrock consisting of slightly weathered dacite. The anchor axis has an inclination of 37° to the horizontal, with an oblique length of 40 m and a maximum burial depth of 48.4 m after excavation. Each anchor features 34 high-precision prestressed anchor holes arranged in a plum blossom pattern, each containing several φ15.2 mm epoxy steel strand cables. Both the front and rear anchor plates are constructed of C55 reinforced concrete.

[0101] like Figure 2 As shown, a slightly weathered dacite formation was used as the surrounding rock for the model anchor near the bridge anchorage project. The surface and rear anchor chamber rock mass were excavated at a scale of 1:10, similar to the actual bridge rock anchor. The rock anchor body had an oblique length of 4m, a 37° inclination with respect to the horizontal, and a 58° azimuth, consistent with the actual bridge anchorage. The maximum vertical depth of the model anchor was 4.84m. Two C55 reinforced concrete anchor plates, measuring 1.3m wide, 1.4m high, and 0.4m thick, were then cast on the front anchor surface. A single C55 reinforced concrete anchor plate, measuring 6.2m wide, 1.5m high, and 0.4m thick, was cast on the rear anchor surface. Finally, twelve 76mm diameter holes were drilled in two rows and six columns in the front and rear anchor plates to apply prestressing force. Seven unbonded φ15.2mm prestressed steel strands were installed in each borehole. Twelve 150-ton hollow hydraulic jacks were installed on the front anchor surface, along with the prestressed steel strands, to form the prestressing loading system. Twenty-eight 300-ton hydraulic jacks were installed on the rear anchor surface to form the rear anchor surface thrust loading system. Fourteen surface extensometers were installed on the front and rear anchor surfaces, and six borehole multi-point extensometers were installed deep within the rock mass to test rock anchor deformation.

[0102] Loading and measurement were performed on a scaled rock anchor model. At 45,408 kN, the first visible crack appeared on the surface. At 71,356 kN, the number and width of surface cracks increased, but the pressure and deformation remained stable. During the loading period from 71,356 kN to 77,843 kN, deformation increased rapidly, and the pressure dropped sharply as the deformation increased. The pressure fluctuated violently and could not remain stable. Simultaneously, the concrete of the rear anchor plate broke and failed at the jacking point. The load-displacement curve revealed that the rock anchor model had a bearing capacity of 71,356 kN, with an upward angle of 37 degrees.

[0103] During the loading process, many surface cracks appeared in the scaled model of rock anchor. Through the temporal and spatial analysis of the cracks, it was generalized into a failure mode in which the rear edge tensile crack surface penetrates, the crack surfaces on both sides track the steep-angle joints and the tensile shear fracture penetrates, and the bottom sliding surface tracks the slip of the gently-angled joints to form an overall failure. The rock anchor failure profile and the rock anchor bearing body were obtained, such as Figure 3 As shown in the figure, the volume of the rock anchor bearing body is calculated to be 107m 3 .

[0104] According to the geological survey report, the density of the slightly weathered dacite rock mass is 2550kg / m 3 The weight of the rock anchor bearing body is calculated to be 2672kN, and the direction is vertically downward.

[0105] like Figure 4As shown in the figure, the stress analysis of the rock anchor bearing body is carried out. Under the limit equilibrium state, the rock anchor bearing body is subjected to a gravity of 2672kN in the vertical downward direction, and an additional load of 71356kN, which is 11 times the design load, in the upward direction of 37°. The stress analysis diagram of the rock anchor bearing body is drawn, and the resistance of the external rock mass to the rock anchor bearing body is obtained by graphical method, which is 69781kN in the downward direction of 35°.

[0106] like Figure 5 As shown in the figure, the gravity component on the force analysis diagram of the rock anchor bearing body is magnified 10 times, and the revised force analysis diagram is redrawn. The additional load on the rock anchor bearing body is obtained by graphical method to be 85828kN.

[0107] The revised rock anchor bearing capacity is determined to be 85,828 kN, or 13.2 times the design load. This represents a 20% increase in bearing capacity compared to the pre-correction value, providing guidance for the safety assessment and optimized design of rock anchors. This revised bearing capacity increase is essentially due to the increase in the rock anchor's own gravity resistance component, and does not account for the increase in shear strength on the failure profile due to the increased gravity. Objectively, due to the complex stress distribution on the shear failure profile, the increase in shear strength on the failure profile due to the increased gravity is difficult to accurately calculate.

[0108] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for correcting the bearing capacity of a rock anchor in a field scale model test, characterized in that: Including steps: S1: Construct a scaled model of rock anchor and conduct on-site scaled model test of rock anchor; S2: Obtain the rock anchor bearing capacity test value and bearing body failure contour; S3: Calculate the volume and gravity of the rock anchor bearing body; S4: Conduct stress analysis on the rock anchor bearing body; Step S4 includes the following sub-steps: S4.1: Take the rock anchor bearing body as an independent unit and treat it as a rigid body; S4.2: Analyze the additional loads applied to the anchorage bearing element during test loading. , the weight W of the rock anchor bearing body itself and the resistance of the external rock mass to the rock anchor bearing body ; S4.3: Label the additional loads obtained in step S2 whose magnitude and direction are known. ; S4.4: Mark the magnitude and direction of the rock anchor bearing body's own weight W obtained in step S3; S5: Draw the force analysis diagram of the rock anchor bearing body; Step S5 includes the following sub-steps: S5.1: It is assumed that when the rock anchor system fails, all external forces acting on the rock anchor bearing body reach a state of mechanical equilibrium; S5.2: Draw a force analysis diagram for the rock anchor bearing body and include and W are drawn end to end; S5.3: According to the triangle closure condition principle of the external force on the system in limit equilibrium, obtain the resistance of the external rock mass to the rock anchor bearing body ; S6: Enlarge the gravity component on the force analysis diagram of the rock anchor bearing body and redraw the corrected force analysis diagram; Step S6 includes the following sub-steps: S6.1: On the force analysis diagram obtained in step S5.3, magnify the weight W of the rock anchor bearing body by N times and use Marking S6.2: Determine the new resultant force F by graphical construction; S6.3: Decompose the resultant force F along the direction of loading and perpendicular to the direction of the rock anchor test. and ; S6.4: The resistance of the original external rock mass to the rock anchor bearing body and the increase in the resistance of the external rock mass to the rock anchor bearing body after amplifying gravity According to the graphical method, the vector summation is performed to obtain the total resistance of the external rock mass to the rock anchor bearing body after the gravity is amplified. ; S6.5: Based on the obtained 、 and Redraw the revised force analysis diagram; S7: Obtain the correction value of the rock anchor bearing capacity; Step S7 includes the following sub-steps: S7.1: Compare the load analysis diagrams before and after correction. and , known The size of the size; S7.2: The revised load analysis diagram will be redrawn Determined as the correction value of the rock anchor bearing capacity.

2. The method for correcting the bearing capacity of a rock anchor anchorage in a field scaled model test according to claim 1, characterized in that: Step S1 includes the following sub-steps: S1.1: Design a scaled model of the rock anchor according to the similarity principle of elastic mechanics. Select a location with representative engineering geological conditions in the actual bridge rock anchor project area and construct a rock anchor model with a scale ratio of 1:N according to the similarity principle. When physical force is ignored, the similarity relationship between the model and the prototype is: Geometric dimensions: ; Elastic modulus: ; strength: ; Load: ; S1.2: Install loading and measuring equipment; S1.3: Load and measure a scaled model of the rock anchor until failure, and plot the load-displacement curve.

3. The method for correcting the bearing capacity of a rock anchor anchorage in a scaled model test on site according to claim 1, characterized in that: Step S2 includes the following sub-steps: S2.1: Obtain the maximum applied load from the load-displacement curve measured during the loading process of the scaled rock anchor model and determine it as the bearing capacity of the scaled rock anchor model; S2.2: By analyzing the time and space of the surface cracks exposed inside and outside the rock anchor model, generalize the failure mode of the rock anchor and the failure profile of the bearing body.

4. The method for correcting the bearing capacity of a rock anchor anchorage in a field scale model test according to claim 1, characterized in that: Step S3 includes the following sub-steps: S3.1: Draw the three-dimensional shape of the rock anchor bearing body through the generalized rock anchor bearing body failure contour and calculate the volume of the rock anchor bearing body V ; S3.2: Based on the calculated rock anchor bearing volume, consult geological survey data to obtain the density of the rock anchor rock mass. ρ The following formula is used to calculate the gravity of the rock anchor bearing body: 。

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